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Commit 64ac24e7 authored by Matthew Wilcox's avatar Matthew Wilcox Committed by Matthew Wilcox
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Generic semaphore implementation 

Semaphores are no longer performance-critical, so a generic C
implementation is better for maintainability, debuggability and
extensibility.  Thanks to Peter Zijlstra for fixing the lockdep
warning.  Thanks to Harvey Harrison for pointing out that the
unlikely() was unnecessary.
Signed-off-by: default avatarMatthew Wilcox <willy@linux.intel.com>
Acked-by: default avatarIngo Molnar <mingo@elte.hu>
parent e48b3dee
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Showing with 314 additions and 7679 deletions
arch/alpha/kernel/Makefile
View file @ 64ac24e7
......@@ -7,7 +7,7 @@ EXTRA_AFLAGS := $(KBUILD_CFLAGS)
EXTRA_CFLAGS := -Werror -Wno-sign-compare
obj-y := entry.o traps.o process.o init_task.o osf_sys.o irq.o \
irq_alpha.o signal.o setup.o ptrace.o time.o semaphore.o \
irq_alpha.o signal.o setup.o ptrace.o time.o \
alpha_ksyms.o systbls.o err_common.o io.o
obj-$(CONFIG_VGA_HOSE) += console.o
......
arch/alpha/kernel/alpha_ksyms.c
View file @ 64ac24e7
......@@ -77,15 +77,6 @@ EXPORT_SYMBOL(__do_clear_user);
EXPORT_SYMBOL(__strncpy_from_user);
EXPORT_SYMBOL(__strnlen_user);
/* Semaphore helper functions. */
EXPORT_SYMBOL(__down_failed);
EXPORT_SYMBOL(__down_failed_interruptible);
EXPORT_SYMBOL(__up_wakeup);
EXPORT_SYMBOL(down);
EXPORT_SYMBOL(down_interruptible);
EXPORT_SYMBOL(down_trylock);
EXPORT_SYMBOL(up);
/*
* SMP-specific symbols.
*/
......
arch/alpha/kernel/semaphore.c deleted 100644 → 0
View file @ e48b3dee
/*
* Alpha semaphore implementation.
*
* (C) Copyright 1996 Linus Torvalds
* (C) Copyright 1999, 2000 Richard Henderson
*/
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/init.h>
/*
* This is basically the PPC semaphore scheme ported to use
* the Alpha ll/sc sequences, so see the PPC code for
* credits.
*/
/*
* Atomically update sem->count.
* This does the equivalent of the following:
*
* old_count = sem->count;
* tmp = MAX(old_count, 0) + incr;
* sem->count = tmp;
* return old_count;
*/
static inline int __sem_update_count(struct semaphore *sem, int incr)
{
long old_count, tmp = 0;
__asm__ __volatile__(
"1: ldl_l %0,%2\n"
" cmovgt %0,%0,%1\n"
" addl %1,%3,%1\n"
" stl_c %1,%2\n"
" beq %1,2f\n"
" mb\n"
".subsection 2\n"
"2: br 1b\n"
".previous"
: "=&r" (old_count), "=&r" (tmp), "=m" (sem->count)
: "Ir" (incr), "1" (tmp), "m" (sem->count));
return old_count;
}
/*
* Perform the "down" function. Return zero for semaphore acquired,
* return negative for signalled out of the function.
*
* If called from down, the return is ignored and the wait loop is
* not interruptible. This means that a task waiting on a semaphore
* using "down()" cannot be killed until someone does an "up()" on
* the semaphore.
*
* If called from down_interruptible, the return value gets checked
* upon return. If the return value is negative then the task continues
* with the negative value in the return register (it can be tested by
* the caller).
*
* Either form may be used in conjunction with "up()".
*/
void __sched
__down_failed(struct semaphore *sem)
{
struct task_struct *tsk = current;
DECLARE_WAITQUEUE(wait, tsk);
#ifdef CONFIG_DEBUG_SEMAPHORE
printk("%s(%d): down failed(%p)\n",
tsk->comm, task_pid_nr(tsk), sem);
#endif
tsk->state = TASK_UNINTERRUPTIBLE;
wmb();
add_wait_queue_exclusive(&sem->wait, &wait);
/*
* Try to get the semaphore. If the count is > 0, then we've
* got the semaphore; we decrement count and exit the loop.
* If the count is 0 or negative, we set it to -1, indicating
* that we are asleep, and then sleep.
*/
while (__sem_update_count(sem, -1) <= 0) {
schedule();
set_task_state(tsk, TASK_UNINTERRUPTIBLE);
}
remove_wait_queue(&sem->wait, &wait);
tsk->state = TASK_RUNNING;
/*
* If there are any more sleepers, wake one of them up so
* that it can either get the semaphore, or set count to -1
* indicating that there are still processes sleeping.
*/
wake_up(&sem->wait);
#ifdef CONFIG_DEBUG_SEMAPHORE
printk("%s(%d): down acquired(%p)\n",
tsk->comm, task_pid_nr(tsk), sem);
#endif
}
int __sched
__down_failed_interruptible(struct semaphore *sem)
{
struct task_struct *tsk = current;
DECLARE_WAITQUEUE(wait, tsk);
long ret = 0;
#ifdef CONFIG_DEBUG_SEMAPHORE
printk("%s(%d): down failed(%p)\n",
tsk->comm, task_pid_nr(tsk), sem);
#endif
tsk->state = TASK_INTERRUPTIBLE;
wmb();
add_wait_queue_exclusive(&sem->wait, &wait);
while (__sem_update_count(sem, -1) <= 0) {
if (signal_pending(current)) {
/*
* A signal is pending - give up trying.
* Set sem->count to 0 if it is negative,
* since we are no longer sleeping.
*/
__sem_update_count(sem, 0);
ret = -EINTR;
break;
}
schedule();
set_task_state(tsk, TASK_INTERRUPTIBLE);
}
remove_wait_queue(&sem->wait, &wait);
tsk->state = TASK_RUNNING;
wake_up(&sem->wait);
#ifdef CONFIG_DEBUG_SEMAPHORE
printk("%s(%d): down %s(%p)\n",
current->comm, task_pid_nr(current),
(ret < 0 ? "interrupted" : "acquired"), sem);
#endif
return ret;
}
void
__up_wakeup(struct semaphore *sem)
{
/*
* Note that we incremented count in up() before we came here,
* but that was ineffective since the result was <= 0, and
* any negative value of count is equivalent to 0.
* This ends up setting count to 1, unless count is now > 0
* (i.e. because some other cpu has called up() in the meantime),
* in which case we just increment count.
*/
__sem_update_count(sem, 1);
wake_up(&sem->wait);
}
void __sched
down(struct semaphore *sem)
{
#ifdef WAITQUEUE_DEBUG
CHECK_MAGIC(sem->__magic);
#endif
#ifdef CONFIG_DEBUG_SEMAPHORE
printk("%s(%d): down(%p) <count=%d> from %p\n",
current->comm, task_pid_nr(current), sem,
atomic_read(&sem->count), __builtin_return_address(0));
#endif
__down(sem);
}
int __sched
down_interruptible(struct semaphore *sem)
{
#ifdef WAITQUEUE_DEBUG
CHECK_MAGIC(sem->__magic);
#endif
#ifdef CONFIG_DEBUG_SEMAPHORE
printk("%s(%d): down(%p) <count=%d> from %p\n",
current->comm, task_pid_nr(current), sem,
atomic_read(&sem->count), __builtin_return_address(0));
#endif
return __down_interruptible(sem);
}
int
down_trylock(struct semaphore *sem)
{
int ret;
#ifdef WAITQUEUE_DEBUG
CHECK_MAGIC(sem->__magic);
#endif
ret = __down_trylock(sem);
#ifdef CONFIG_DEBUG_SEMAPHORE
printk("%s(%d): down_trylock %s from %p\n",
current->comm, task_pid_nr(current),
ret ? "failed" : "acquired",
__builtin_return_address(0));
#endif
return ret;
}
void
up(struct semaphore *sem)
{
#ifdef WAITQUEUE_DEBUG
CHECK_MAGIC(sem->__magic);
#endif
#ifdef CONFIG_DEBUG_SEMAPHORE
printk("%s(%d): up(%p) <count=%d> from %p\n",
current->comm, task_pid_nr(current), sem,
atomic_read(&sem->count), __builtin_return_address(0));
#endif
__up(sem);
}
arch/arm/kernel/Makefile
View file @ 64ac24e7
......@@ -7,7 +7,7 @@ AFLAGS_head.o := -DTEXT_OFFSET=$(TEXT_OFFSET)
# Object file lists.
obj-y := compat.o entry-armv.o entry-common.o irq.o \
process.o ptrace.o semaphore.o setup.o signal.o \
process.o ptrace.o setup.o signal.o \
sys_arm.o stacktrace.o time.o traps.o
obj-$(CONFIG_ISA_DMA_API) += dma.o
......
arch/arm/kernel/semaphore.c deleted 100644 → 0
View file @ e48b3dee
/*
* ARM semaphore implementation, taken from
*
* i386 semaphore implementation.
*
* (C) Copyright 1999 Linus Torvalds
*
* Modified for ARM by Russell King
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <asm/semaphore.h>
/*
* Semaphores are implemented using a two-way counter:
* The "count" variable is decremented for each process
* that tries to acquire the semaphore, while the "sleeping"
* variable is a count of such acquires.
*
* Notably, the inline "up()" and "down()" functions can
* efficiently test if they need to do any extra work (up
* needs to do something only if count was negative before
* the increment operation.
*
* "sleeping" and the contention routine ordering is
* protected by the semaphore spinlock.
*
* Note that these functions are only called when there is
* contention on the lock, and as such all this is the
* "non-critical" part of the whole semaphore business. The
* critical part is the inline stuff in <asm/semaphore.h>
* where we want to avoid any extra jumps and calls.
*/
/*
* Logic:
* - only on a boundary condition do we need to care. When we go
* from a negative count to a non-negative, we wake people up.
* - when we go from a non-negative count to a negative do we
* (a) synchronize with the "sleeper" count and (b) make sure
* that we're on the wakeup list before we synchronize so that
* we cannot lose wakeup events.
*/
void __up(struct semaphore *sem)
{
wake_up(&sem->wait);
}
static DEFINE_SPINLOCK(semaphore_lock);
void __sched __down(struct semaphore * sem)
{
struct task_struct *tsk = current;
DECLARE_WAITQUEUE(wait, tsk);
tsk->state = TASK_UNINTERRUPTIBLE;
add_wait_queue_exclusive(&sem->wait, &wait);
spin_lock_irq(&semaphore_lock);
sem->sleepers++;
for (;;) {
int sleepers = sem->sleepers;
/*
* Add "everybody else" into it. They aren't
* playing, because we own the spinlock.
*/
if (!atomic_add_negative(sleepers - 1, &sem->count)) {
sem->sleepers = 0;
break;
}
sem->sleepers = 1; /* us - see -1 above */
spin_unlock_irq(&semaphore_lock);
schedule();
tsk->state = TASK_UNINTERRUPTIBLE;
spin_lock_irq(&semaphore_lock);
}
spin_unlock_irq(&semaphore_lock);
remove_wait_queue(&sem->wait, &wait);
tsk->state = TASK_RUNNING;
wake_up(&sem->wait);
}
int __sched __down_interruptible(struct semaphore * sem)
{
int retval = 0;
struct task_struct *tsk = current;
DECLARE_WAITQUEUE(wait, tsk);
tsk->state = TASK_INTERRUPTIBLE;
add_wait_queue_exclusive(&sem->wait, &wait);
spin_lock_irq(&semaphore_lock);
sem->sleepers ++;
for (;;) {
int sleepers = sem->sleepers;
/*
* With signals pending, this turns into
* the trylock failure case - we won't be
* sleeping, and we* can't get the lock as
* it has contention. Just correct the count
* and exit.
*/
if (signal_pending(current)) {
retval = -EINTR;
sem->sleepers = 0;
atomic_add(sleepers, &sem->count);
break;
}
/*
* Add "everybody else" into it. They aren't
* playing, because we own the spinlock. The
* "-1" is because we're still hoping to get
* the lock.
*/
if (!atomic_add_negative(sleepers - 1, &sem->count)) {
sem->sleepers = 0;
break;
}
sem->sleepers = 1; /* us - see -1 above */
spin_unlock_irq(&semaphore_lock);
schedule();
tsk->state = TASK_INTERRUPTIBLE;
spin_lock_irq(&semaphore_lock);
}
spin_unlock_irq(&semaphore_lock);
tsk->state = TASK_RUNNING;
remove_wait_queue(&sem->wait, &wait);
wake_up(&sem->wait);
return retval;
}
/*
* Trylock failed - make sure we correct for
* having decremented the count.
*
* We could have done the trylock with a
* single "cmpxchg" without failure cases,
* but then it wouldn't work on a 386.
*/
int __down_trylock(struct semaphore * sem)
{
int sleepers;
unsigned long flags;
spin_lock_irqsave(&semaphore_lock, flags);
sleepers = sem->sleepers + 1;
sem->sleepers = 0;
/*
* Add "everybody else" and us into it. They aren't
* playing, because we own the spinlock.
*/
if (!atomic_add_negative(sleepers, &sem->count))
wake_up(&sem->wait);
spin_unlock_irqrestore(&semaphore_lock, flags);
return 1;
}
/*
* The semaphore operations have a special calling sequence that
* allow us to do a simpler in-line version of them. These routines
* need to convert that sequence back into the C sequence when
* there is contention on the semaphore.
*
* ip contains the semaphore pointer on entry. Save the C-clobbered
* registers (r0 to r3 and lr), but not ip, as we use it as a return
* value in some cases..
* To remain AAPCS compliant (64-bit stack align) we save r4 as well.
*/
asm(" .section .sched.text,\"ax\",%progbits \n\
.align 5 \n\
.globl __down_failed \n\
__down_failed: \n\
stmfd sp!, {r0 - r4, lr} \n\
mov r0, ip \n\
bl __down \n\
ldmfd sp!, {r0 - r4, pc} \n\
\n\
.align 5 \n\
.globl __down_interruptible_failed \n\
__down_interruptible_failed: \n\
stmfd sp!, {r0 - r4, lr} \n\
mov r0, ip \n\
bl __down_interruptible \n\
mov ip, r0 \n\
ldmfd sp!, {r0 - r4, pc} \n\
\n\
.align 5 \n\
.globl __down_trylock_failed \n\
__down_trylock_failed: \n\
stmfd sp!, {r0 - r4, lr} \n\
mov r0, ip \n\
bl __down_trylock \n\
mov ip, r0 \n\
ldmfd sp!, {r0 - r4, pc} \n\
\n\
.align 5 \n\
.globl __up_wakeup \n\
__up_wakeup: \n\
stmfd sp!, {r0 - r4, lr} \n\
mov r0, ip \n\
bl __up \n\
ldmfd sp!, {r0 - r4, pc} \n\
");
EXPORT_SYMBOL(__down_failed);
EXPORT_SYMBOL(__down_interruptible_failed);
EXPORT_SYMBOL(__down_trylock_failed);
EXPORT_SYMBOL(__up_wakeup);
arch/avr32/kernel/Makefile
View file @ 64ac24e7
......@@ -6,7 +6,7 @@ extra-y := head.o vmlinux.lds
obj-$(CONFIG_SUBARCH_AVR32B) += entry-avr32b.o
obj-y += syscall_table.o syscall-stubs.o irq.o
obj-y += setup.o traps.o semaphore.o ocd.o ptrace.o
obj-y += setup.o traps.o ocd.o ptrace.o
obj-y += signal.o sys_avr32.o process.o time.o
obj-y += init_task.o switch_to.o cpu.o
obj-$(CONFIG_MODULES) += module.o avr32_ksyms.o
......
arch/avr32/kernel/semaphore.c deleted 100644 → 0
View file @ e48b3dee
/*
* AVR32 sempahore implementation.
*
* Copyright (C) 2004-2006 Atmel Corporation
*
* Based on linux/arch/i386/kernel/semaphore.c
* Copyright (C) 1999 Linus Torvalds
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/module.h>
#include <asm/semaphore.h>
#include <asm/atomic.h>
/*
* Semaphores are implemented using a two-way counter:
* The "count" variable is decremented for each process
* that tries to acquire the semaphore, while the "sleeping"
* variable is a count of such acquires.
*
* Notably, the inline "up()" and "down()" functions can
* efficiently test if they need to do any extra work (up
* needs to do something only if count was negative before
* the increment operation.
*
* "sleeping" and the contention routine ordering is protected
* by the spinlock in the semaphore's waitqueue head.
*
* Note that these functions are only called when there is
* contention on the lock, and as such all this is the
* "non-critical" part of the whole semaphore business. The
* critical part is the inline stuff in <asm/semaphore.h>
* where we want to avoid any extra jumps and calls.
*/
/*
* Logic:
* - only on a boundary condition do we need to care. When we go
* from a negative count to a non-negative, we wake people up.
* - when we go from a non-negative count to a negative do we
* (a) synchronize with the "sleeper" count and (b) make sure
* that we're on the wakeup list before we synchronize so that
* we cannot lose wakeup events.
*/
void __up(struct semaphore *sem)
{
wake_up(&sem->wait);
}
EXPORT_SYMBOL(__up);
void __sched __down(struct semaphore *sem)
{
struct task_struct *tsk = current;
DECLARE_WAITQUEUE(wait, tsk);
unsigned long flags;
tsk->state = TASK_UNINTERRUPTIBLE;
spin_lock_irqsave(&sem->wait.lock, flags);
add_wait_queue_exclusive_locked(&sem->wait, &wait);
sem->sleepers++;
for (;;) {
int sleepers = sem->sleepers;
/*
* Add "everybody else" into it. They aren't
* playing, because we own the spinlock in
* the wait_queue_head.
*/
if (atomic_add_return(sleepers - 1, &sem->count) >= 0) {
sem->sleepers = 0;
break;
}
sem->sleepers = 1; /* us - see -1 above */
spin_unlock_irqrestore(&sem->wait.lock, flags);
schedule();
spin_lock_irqsave(&sem->wait.lock, flags);
tsk->state = TASK_UNINTERRUPTIBLE;
}
remove_wait_queue_locked(&sem->wait, &wait);
wake_up_locked(&sem->wait);
spin_unlock_irqrestore(&sem->wait.lock, flags);
tsk->state = TASK_RUNNING;
}
EXPORT_SYMBOL(__down);
int __sched __down_interruptible(struct semaphore *sem)
{
int retval = 0;
struct task_struct *tsk = current;
DECLARE_WAITQUEUE(wait, tsk);
unsigned long flags;
tsk->state = TASK_INTERRUPTIBLE;
spin_lock_irqsave(&sem->wait.lock, flags);
add_wait_queue_exclusive_locked(&sem->wait, &wait);
sem->sleepers++;
for (;;) {
int sleepers = sem->sleepers;
/*
* With signals pending, this turns into the trylock
* failure case - we won't be sleeping, and we can't
* get the lock as it has contention. Just correct the
* count and exit.
*/
if (signal_pending(current)) {
retval = -EINTR;
sem->sleepers = 0;
atomic_add(sleepers, &sem->count);
break;
}
/*
* Add "everybody else" into it. They aren't
* playing, because we own the spinlock in
* the wait_queue_head.
*/
if (atomic_add_return(sleepers - 1, &sem->count) >= 0) {
sem->sleepers = 0;
break;
}
sem->sleepers = 1; /* us - see -1 above */
spin_unlock_irqrestore(&sem->wait.lock, flags);
schedule();
spin_lock_irqsave(&sem->wait.lock, flags);
tsk->state = TASK_INTERRUPTIBLE;
}
remove_wait_queue_locked(&sem->wait, &wait);
wake_up_locked(&sem->wait);
spin_unlock_irqrestore(&sem->wait.lock, flags);
tsk->state = TASK_RUNNING;
return retval;
}
EXPORT_SYMBOL(__down_interruptible);
arch/blackfin/Kconfig
View file @ 64ac24e7
......@@ -31,10 +31,6 @@ config ZONE_DMA
bool
default y
config SEMAPHORE_SLEEPERS
bool
default y
config GENERIC_FIND_NEXT_BIT
bool
default y
......
arch/blackfin/kernel/bfin_ksyms.c
View file @ 64ac24e7
......@@ -42,11 +42,6 @@ EXPORT_SYMBOL(ip_fast_csum);
EXPORT_SYMBOL(kernel_thread);
EXPORT_SYMBOL(__up);
EXPORT_SYMBOL(__down);
EXPORT_SYMBOL(__down_trylock);
EXPORT_SYMBOL(__down_interruptible);
EXPORT_SYMBOL(is_in_rom);
EXPORT_SYMBOL(bfin_return_from_exception);
......
arch/cris/kernel/Makefile
View file @ 64ac24e7
......@@ -5,8 +5,7 @@
extra-y := vmlinux.lds
obj-y := process.o traps.o irq.o ptrace.o setup.o \
time.o sys_cris.o semaphore.o
obj-y := process.o traps.o irq.o ptrace.o setup.o time.o sys_cris.o
obj-$(CONFIG_MODULES) += crisksyms.o
obj-$(CONFIG_MODULES) += module.o
......
arch/cris/kernel/crisksyms.c
View file @ 64ac24e7
......@@ -9,7 +9,6 @@
#include <linux/string.h>
#include <linux/tty.h>
#include <asm/semaphore.h>
#include <asm/processor.h>
#include <asm/uaccess.h>
#include <asm/checksum.h>
......@@ -49,12 +48,6 @@ EXPORT_SYMBOL(__negdi2);
EXPORT_SYMBOL(__ioremap);
EXPORT_SYMBOL(iounmap);
/* Semaphore functions */
EXPORT_SYMBOL(__up);
EXPORT_SYMBOL(__down);
EXPORT_SYMBOL(__down_interruptible);
EXPORT_SYMBOL(__down_trylock);
/* Userspace access functions */
EXPORT_SYMBOL(__copy_user_zeroing);
EXPORT_SYMBOL(__copy_user);
......
arch/cris/kernel/semaphore.c deleted 100644 → 0
View file @ e48b3dee
/*
* Generic semaphore code. Buyer beware. Do your own
* specific changes in <asm/semaphore-helper.h>
*/
#include <linux/sched.h>
#include <asm/semaphore-helper.h>
/*
* Semaphores are implemented using a two-way counter:
* The "count" variable is decremented for each process
* that tries to sleep, while the "waking" variable is
* incremented when the "up()" code goes to wake up waiting
* processes.
*
* Notably, the inline "up()" and "down()" functions can
* efficiently test if they need to do any extra work (up
* needs to do something only if count was negative before
* the increment operation.
*
* waking_non_zero() (from asm/semaphore.h) must execute
* atomically.
*
* When __up() is called, the count was negative before
* incrementing it, and we need to wake up somebody.
*
* This routine adds one to the count of processes that need to
* wake up and exit. ALL waiting processes actually wake up but
* only the one that gets to the "waking" field first will gate
* through and acquire the semaphore. The others will go back
* to sleep.
*
* Note that these functions are only called when there is
* contention on the lock, and as such all this is the
* "non-critical" part of the whole semaphore business. The
* critical part is the inline stuff in <asm/semaphore.h>
* where we want to avoid any extra jumps and calls.
*/
void __up(struct semaphore *sem)
{
wake_one_more(sem);
wake_up(&sem->wait);
}
/*
* Perform the "down" function. Return zero for semaphore acquired,
* return negative for signalled out of the function.
*
* If called from __down, the return is ignored and the wait loop is
* not interruptible. This means that a task waiting on a semaphore
* using "down()" cannot be killed until someone does an "up()" on
* the semaphore.
*
* If called from __down_interruptible, the return value gets checked
* upon return. If the return value is negative then the task continues
* with the negative value in the return register (it can be tested by
* the caller).
*
* Either form may be used in conjunction with "up()".
*
*/
#define DOWN_VAR \
struct task_struct *tsk = current; \
wait_queue_t wait; \
init_waitqueue_entry(&wait, tsk);
#define DOWN_HEAD(task_state) \
\
\
tsk->state = (task_state); \
add_wait_queue(&sem->wait, &wait); \
\
/* \
* Ok, we're set up. sem->count is known to be less than zero \
* so we must wait. \
* \
* We can let go the lock for purposes of waiting. \
* We re-acquire it after awaking so as to protect \
* all semaphore operations. \
* \
* If "up()" is called before we call waking_non_zero() then \
* we will catch it right away. If it is called later then \
* we will have to go through a wakeup cycle to catch it. \
* \
* Multiple waiters contend for the semaphore lock to see \
* who gets to gate through and who has to wait some more. \
*/ \
for (;;) {
#define DOWN_TAIL(task_state) \
tsk->state = (task_state); \
} \
tsk->state = TASK_RUNNING; \
remove_wait_queue(&sem->wait, &wait);
void __sched __down(struct semaphore * sem)
{
DOWN_VAR
DOWN_HEAD(TASK_UNINTERRUPTIBLE)
if (waking_non_zero(sem))
break;
schedule();
DOWN_TAIL(TASK_UNINTERRUPTIBLE)
}
int __sched __down_interruptible(struct semaphore * sem)
{
int ret = 0;
DOWN_VAR
DOWN_HEAD(TASK_INTERRUPTIBLE)
ret = waking_non_zero_interruptible(sem, tsk);
if (ret)
{
if (ret == 1)
/* ret != 0 only if we get interrupted -arca */
ret = 0;
break;
}
schedule();
DOWN_TAIL(TASK_INTERRUPTIBLE)
return ret;
}
int __down_trylock(struct semaphore * sem)
{
return waking_non_zero_trylock(sem);
}
arch/frv/kernel/Makefile
View file @ 64ac24e7
......@@ -9,7 +9,7 @@ extra-y:= head.o init_task.o vmlinux.lds
obj-y := $(heads-y) entry.o entry-table.o break.o switch_to.o kernel_thread.o \
kernel_execve.o process.o traps.o ptrace.o signal.o dma.o \
sys_frv.o time.o semaphore.o setup.o frv_ksyms.o \
sys_frv.o time.o setup.o frv_ksyms.o \
debug-stub.o irq.o sleep.o uaccess.o
obj-$(CONFIG_GDBSTUB) += gdb-stub.o gdb-io.o
......
arch/frv/kernel/frv_ksyms.c
View file @ 64ac24e7
......@@ -12,7 +12,6 @@
#include <asm/pgalloc.h>
#include <asm/irq.h>
#include <asm/io.h>
#include <asm/semaphore.h>
#include <asm/checksum.h>
#include <asm/hardirq.h>
#include <asm/cacheflush.h>
......
arch/frv/kernel/semaphore.c deleted 100644 → 0
View file @ e48b3dee
/* semaphore.c: FR-V semaphores
*
* Copyright (C) 2003 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
* - Derived from lib/rwsem-spinlock.c
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/sched.h>
#include <linux/module.h>
#include <asm/semaphore.h>
struct sem_waiter {
struct list_head list;
struct task_struct *task;
};
#ifdef CONFIG_DEBUG_SEMAPHORE
void semtrace(struct semaphore *sem, const char *str)
{
if (sem->debug)
printk("[%d] %s({%d,%d})\n",
current->pid,
str,
sem->counter,
list_empty(&sem->wait_list) ? 0 : 1);
}
#else
#define semtrace(SEM,STR) do { } while(0)
#endif
/*
* wait for a token to be granted from a semaphore
* - entered with lock held and interrupts disabled
*/
void __down(struct semaphore *sem, unsigned long flags)
{
struct task_struct *tsk = current;
struct sem_waiter waiter;
semtrace(sem, "Entering __down");
/* set up my own style of waitqueue */
waiter.task = tsk;
get_task_struct(tsk);
list_add_tail(&waiter.list, &sem->wait_list);
/* we don't need to touch the semaphore struct anymore */
spin_unlock_irqrestore(&sem->wait_lock, flags);
/* wait to be given the semaphore */
set_task_state(tsk, TASK_UNINTERRUPTIBLE);
for (;;) {
if (list_empty(&waiter.list))
break;
schedule();
set_task_state(tsk, TASK_UNINTERRUPTIBLE);
}
tsk->state = TASK_RUNNING;
semtrace(sem, "Leaving __down");
}
EXPORT_SYMBOL(__down);
/*
* interruptibly wait for a token to be granted from a semaphore
* - entered with lock held and interrupts disabled
*/
int __down_interruptible(struct semaphore *sem, unsigned long flags)
{
struct task_struct *tsk = current;
struct sem_waiter waiter;
int ret;
semtrace(sem,"Entering __down_interruptible");
/* set up my own style of waitqueue */
waiter.task = tsk;
get_task_struct(tsk);
list_add_tail(&waiter.list, &sem->wait_list);
/* we don't need to touch the semaphore struct anymore */
set_task_state(tsk, TASK_INTERRUPTIBLE);
spin_unlock_irqrestore(&sem->wait_lock, flags);
/* wait to be given the semaphore */
ret = 0;
for (;;) {
if (list_empty(&waiter.list))
break;
if (unlikely(signal_pending(current)))
goto interrupted;
schedule();
set_task_state(tsk, TASK_INTERRUPTIBLE);
}
out:
tsk->state = TASK_RUNNING;
semtrace(sem, "Leaving __down_interruptible");
return ret;
interrupted:
spin_lock_irqsave(&sem->wait_lock, flags);
if (!list_empty(&waiter.list)) {
list_del(&waiter.list);
ret = -EINTR;
}
spin_unlock_irqrestore(&sem->wait_lock, flags);
if (ret == -EINTR)
put_task_struct(current);
goto out;
}
EXPORT_SYMBOL(__down_interruptible);
/*
* release a single token back to a semaphore
* - entered with lock held and interrupts disabled
*/
void __up(struct semaphore *sem)
{
struct task_struct *tsk;
struct sem_waiter *waiter;
semtrace(sem,"Entering __up");
/* grant the token to the process at the front of the queue */
waiter = list_entry(sem->wait_list.next, struct sem_waiter, list);
/* We must be careful not to touch 'waiter' after we set ->task = NULL.
* It is allocated on the waiter's stack and may become invalid at
* any time after that point (due to a wakeup from another source).
*/
list_del_init(&waiter->list);
tsk = waiter->task;
mb();
waiter->task = NULL;
wake_up_process(tsk);
put_task_struct(tsk);
semtrace(sem,"Leaving __up");
}
EXPORT_SYMBOL(__up);
arch/h8300/kernel/Makefile
View file @ 64ac24e7
......@@ -5,7 +5,7 @@
extra-y := vmlinux.lds
obj-y := process.o traps.o ptrace.o irq.o \
sys_h8300.o time.o semaphore.o signal.o \
sys_h8300.o time.o signal.o \
setup.o gpio.o init_task.o syscalls.o \
entry.o
......
arch/h8300/kernel/h8300_ksyms.c
View file @ 64ac24e7
......@@ -12,7 +12,6 @@
#include <asm/pgalloc.h>
#include <asm/irq.h>
#include <asm/io.h>
#include <asm/semaphore.h>
#include <asm/checksum.h>
#include <asm/current.h>
#include <asm/gpio.h>
......
arch/h8300/kernel/semaphore.c deleted 100644 → 0
View file @ e48b3dee
/*
* Generic semaphore code. Buyer beware. Do your own
* specific changes in <asm/semaphore-helper.h>
*/
#include <linux/sched.h>
#include <linux/init.h>
#include <asm/semaphore-helper.h>
#ifndef CONFIG_RMW_INSNS
spinlock_t semaphore_wake_lock;
#endif
/*
* Semaphores are implemented using a two-way counter:
* The "count" variable is decremented for each process
* that tries to sleep, while the "waking" variable is
* incremented when the "up()" code goes to wake up waiting
* processes.
*
* Notably, the inline "up()" and "down()" functions can
* efficiently test if they need to do any extra work (up
* needs to do something only if count was negative before
* the increment operation.
*
* waking_non_zero() (from asm/semaphore.h) must execute
* atomically.
*
* When __up() is called, the count was negative before
* incrementing it, and we need to wake up somebody.
*
* This routine adds one to the count of processes that need to
* wake up and exit. ALL waiting processes actually wake up but
* only the one that gets to the "waking" field first will gate
* through and acquire the semaphore. The others will go back
* to sleep.
*
* Note that these functions are only called when there is
* contention on the lock, and as such all this is the
* "non-critical" part of the whole semaphore business. The
* critical part is the inline stuff in <asm/semaphore.h>
* where we want to avoid any extra jumps and calls.
*/
void __up(struct semaphore *sem)
{
wake_one_more(sem);
wake_up(&sem->wait);
}
/*
* Perform the "down" function. Return zero for semaphore acquired,
* return negative for signalled out of the function.
*
* If called from __down, the return is ignored and the wait loop is
* not interruptible. This means that a task waiting on a semaphore
* using "down()" cannot be killed until someone does an "up()" on
* the semaphore.
*
* If called from __down_interruptible, the return value gets checked
* upon return. If the return value is negative then the task continues
* with the negative value in the return register (it can be tested by
* the caller).
*
* Either form may be used in conjunction with "up()".
*
*/
#define DOWN_HEAD(task_state) \
\
\
current->state = (task_state); \
add_wait_queue(&sem->wait, &wait); \
\
/* \
* Ok, we're set up. sem->count is known to be less than zero \
* so we must wait. \
* \
* We can let go the lock for purposes of waiting. \
* We re-acquire it after awaking so as to protect \
* all semaphore operations. \
* \
* If "up()" is called before we call waking_non_zero() then \
* we will catch it right away. If it is called later then \
* we will have to go through a wakeup cycle to catch it. \
* \
* Multiple waiters contend for the semaphore lock to see \
* who gets to gate through and who has to wait some more. \
*/ \
for (;;) {
#define DOWN_TAIL(task_state) \
current->state = (task_state); \
} \
current->state = TASK_RUNNING; \
remove_wait_queue(&sem->wait, &wait);
void __sched __down(struct semaphore * sem)
{
DECLARE_WAITQUEUE(wait, current);
DOWN_HEAD(TASK_UNINTERRUPTIBLE)
if (waking_non_zero(sem))
break;
schedule();
DOWN_TAIL(TASK_UNINTERRUPTIBLE)
}
int __sched __down_interruptible(struct semaphore * sem)
{
DECLARE_WAITQUEUE(wait, current);
int ret = 0;
DOWN_HEAD(TASK_INTERRUPTIBLE)
ret = waking_non_zero_interruptible(sem, current);
if (ret)
{
if (ret == 1)
/* ret != 0 only if we get interrupted -arca */
ret = 0;
break;
}
schedule();
DOWN_TAIL(TASK_INTERRUPTIBLE)
return ret;
}
int __down_trylock(struct semaphore * sem)
{
return waking_non_zero_trylock(sem);
}
arch/ia64/kernel/Makefile
View file @ 64ac24e7
......@@ -6,7 +6,7 @@ extra-y := head.o init_task.o vmlinux.lds
obj-y := acpi.o entry.o efi.o efi_stub.o gate-data.o fsys.o ia64_ksyms.o irq.o irq_ia64.o \
irq_lsapic.o ivt.o machvec.o pal.o patch.o process.o perfmon.o ptrace.o sal.o \
salinfo.o semaphore.o setup.o signal.o sys_ia64.o time.o traps.o unaligned.o \
salinfo.o setup.o signal.o sys_ia64.o time.o traps.o unaligned.o \
unwind.o mca.o mca_asm.o topology.o
obj-$(CONFIG_IA64_BRL_EMU) += brl_emu.o
......
arch/ia64/kernel/ia64_ksyms.c
View file @ 64ac24e7
......@@ -19,12 +19,6 @@ EXPORT_SYMBOL_GPL(empty_zero_page);
EXPORT_SYMBOL(ip_fast_csum); /* hand-coded assembly */
EXPORT_SYMBOL(csum_ipv6_magic);
#include <asm/semaphore.h>
EXPORT_SYMBOL(__down);
EXPORT_SYMBOL(__down_interruptible);
EXPORT_SYMBOL(__down_trylock);
EXPORT_SYMBOL(__up);
#include <asm/page.h>
EXPORT_SYMBOL(clear_page);
......
arch/ia64/kernel/semaphore.c deleted 100644 → 0
View file @ e48b3dee
/*
* IA-64 semaphore implementation (derived from x86 version).
*
* Copyright (C) 1999-2000, 2002 Hewlett-Packard Co
* David Mosberger-Tang <davidm@hpl.hp.com>
*/
/*
* Semaphores are implemented using a two-way counter: The "count"
* variable is decremented for each process that tries to acquire the
* semaphore, while the "sleepers" variable is a count of such
* acquires.
*
* Notably, the inline "up()" and "down()" functions can efficiently
* test if they need to do any extra work (up needs to do something
* only if count was negative before the increment operation.
*
* "sleeping" and the contention routine ordering is protected
* by the spinlock in the semaphore's waitqueue head.
*
* Note that these functions are only called when there is contention
* on the lock, and as such all this is the "non-critical" part of the
* whole semaphore business. The critical part is the inline stuff in
* <asm/semaphore.h> where we want to avoid any extra jumps and calls.
*/
#include <linux/sched.h>
#include <linux/init.h>
#include <asm/errno.h>
#include <asm/semaphore.h>
/*
* Logic:
* - Only on a boundary condition do we need to care. When we go
* from a negative count to a non-negative, we wake people up.
* - When we go from a non-negative count to a negative do we
* (a) synchronize with the "sleepers" count and (b) make sure
* that we're on the wakeup list before we synchronize so that
* we cannot lose wakeup events.
*/
void
__up (struct semaphore *sem)
{
wake_up(&sem->wait);
}
void __sched __down (struct semaphore *sem)
{
struct task_struct *tsk = current;
DECLARE_WAITQUEUE(wait, tsk);
unsigned long flags;
tsk->state = TASK_UNINTERRUPTIBLE;
spin_lock_irqsave(&sem->wait.lock, flags);
add_wait_queue_exclusive_locked(&sem->wait, &wait);
sem->sleepers++;
for (;;) {
int sleepers = sem->sleepers;
/*
* Add "everybody else" into it. They aren't
* playing, because we own the spinlock in
* the wait_queue_head.
*/
if (!atomic_add_negative(sleepers - 1, &sem->count)) {
sem->sleepers = 0;
break;
}
sem->sleepers = 1; /* us - see -1 above */
spin_unlock_irqrestore(&sem->wait.lock, flags);
schedule();
spin_lock_irqsave(&sem->wait.lock, flags);
tsk->state = TASK_UNINTERRUPTIBLE;
}
remove_wait_queue_locked(&sem->wait, &wait);
wake_up_locked(&sem->wait);
spin_unlock_irqrestore(&sem->wait.lock, flags);
tsk->state = TASK_RUNNING;
}
int __sched __down_interruptible (struct semaphore * sem)
{
int retval = 0;
struct task_struct *tsk = current;
DECLARE_WAITQUEUE(wait, tsk);
unsigned long flags;
tsk->state = TASK_INTERRUPTIBLE;
spin_lock_irqsave(&sem->wait.lock, flags);
add_wait_queue_exclusive_locked(&sem->wait, &wait);
sem->sleepers ++;
for (;;) {
int sleepers = sem->sleepers;
/*
* With signals pending, this turns into
* the trylock failure case - we won't be
* sleeping, and we* can't get the lock as
* it has contention. Just correct the count
* and exit.
*/
if (signal_pending(current)) {
retval = -EINTR;
sem->sleepers = 0;
atomic_add(sleepers, &sem->count);
break;
}
/*
* Add "everybody else" into it. They aren't
* playing, because we own the spinlock in
* wait_queue_head. The "-1" is because we're
* still hoping to get the semaphore.
*/
if (!atomic_add_negative(sleepers - 1, &sem->count)) {
sem->sleepers = 0;
break;
}
sem->sleepers = 1; /* us - see -1 above */
spin_unlock_irqrestore(&sem->wait.lock, flags);
schedule();
spin_lock_irqsave(&sem->wait.lock, flags);
tsk->state = TASK_INTERRUPTIBLE;
}
remove_wait_queue_locked(&sem->wait, &wait);
wake_up_locked(&sem->wait);
spin_unlock_irqrestore(&sem->wait.lock, flags);
tsk->state = TASK_RUNNING;
return retval;
}
/*
* Trylock failed - make sure we correct for having decremented the
* count.
*/
int
__down_trylock (struct semaphore *sem)
{
unsigned long flags;
int sleepers;
spin_lock_irqsave(&sem->wait.lock, flags);
sleepers = sem->sleepers + 1;
sem->sleepers = 0;
/*
* Add "everybody else" and us into it. They aren't
* playing, because we own the spinlock in the
* wait_queue_head.
*/
if (!atomic_add_negative(sleepers, &sem->count)) {
wake_up_locked(&sem->wait);
}
spin_unlock_irqrestore(&sem->wait.lock, flags);
return 1;
}
arch/m32r/kernel/Makefile
View file @ 64ac24e7
......@@ -5,7 +5,7 @@
extra-y := head.o init_task.o vmlinux.lds
obj-y := process.o entry.o traps.o align.o irq.o setup.o time.o \
m32r_ksyms.o sys_m32r.o semaphore.o signal.o ptrace.o
m32r_ksyms.o sys_m32r.o signal.o ptrace.o
obj-$(CONFIG_SMP) += smp.o smpboot.o
obj-$(CONFIG_MODULES) += module.o
......
arch/m32r/kernel/m32r_ksyms.c
View file @ 64ac24e7
......@@ -7,7 +7,6 @@
#include <linux/interrupt.h>
#include <linux/string.h>
#include <asm/semaphore.h>
#include <asm/processor.h>
#include <asm/uaccess.h>
#include <asm/checksum.h>
......@@ -22,10 +21,6 @@ EXPORT_SYMBOL(dump_fpu);
EXPORT_SYMBOL(__ioremap);
EXPORT_SYMBOL(iounmap);
EXPORT_SYMBOL(kernel_thread);
EXPORT_SYMBOL(__down);
EXPORT_SYMBOL(__down_interruptible);
EXPORT_SYMBOL(__up);
EXPORT_SYMBOL(__down_trylock);
/* Networking helper routines. */
/* Delay loops */
......
arch/m32r/kernel/semaphore.c deleted 100644 → 0
View file @ e48b3dee
/*
* linux/arch/m32r/semaphore.c
* orig : i386 2.6.4
*
* M32R semaphore implementation.
*
* Copyright (c) 2002 - 2004 Hitoshi Yamamoto
*/
/*
* i386 semaphore implementation.
*
* (C) Copyright 1999 Linus Torvalds
*
* Portions Copyright 1999 Red Hat, Inc.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* rw semaphores implemented November 1999 by Benjamin LaHaise <bcrl@kvack.org>
*/
#include <linux/sched.h>
#include <linux/err.h>
#include <linux/init.h>
#include <asm/semaphore.h>
/*
* Semaphores are implemented using a two-way counter:
* The "count" variable is decremented for each process
* that tries to acquire the semaphore, while the "sleeping"
* variable is a count of such acquires.
*
* Notably, the inline "up()" and "down()" functions can
* efficiently test if they need to do any extra work (up
* needs to do something only if count was negative before
* the increment operation.
*
* "sleeping" and the contention routine ordering is protected
* by the spinlock in the semaphore's waitqueue head.
*
* Note that these functions are only called when there is
* contention on the lock, and as such all this is the
* "non-critical" part of the whole semaphore business. The
* critical part is the inline stuff in <asm/semaphore.h>
* where we want to avoid any extra jumps and calls.
*/
/*
* Logic:
* - only on a boundary condition do we need to care. When we go
* from a negative count to a non-negative, we wake people up.
* - when we go from a non-negative count to a negative do we
* (a) synchronize with the "sleeper" count and (b) make sure
* that we're on the wakeup list before we synchronize so that
* we cannot lose wakeup events.
*/
asmlinkage void __up(struct semaphore *sem)
{
wake_up(&sem->wait);
}
asmlinkage void __sched __down(struct semaphore * sem)
{
struct task_struct *tsk = current;
DECLARE_WAITQUEUE(wait, tsk);
unsigned long flags;
tsk->state = TASK_UNINTERRUPTIBLE;
spin_lock_irqsave(&sem->wait.lock, flags);
add_wait_queue_exclusive_locked(&sem->wait, &wait);
sem->sleepers++;
for (;;) {
int sleepers = sem->sleepers;
/*
* Add "everybody else" into it. They aren't
* playing, because we own the spinlock in
* the wait_queue_head.
*/
if (!atomic_add_negative(sleepers - 1, &sem->count)) {
sem->sleepers = 0;
break;
}
sem->sleepers = 1; /* us - see -1 above */
spin_unlock_irqrestore(&sem->wait.lock, flags);
schedule();
spin_lock_irqsave(&sem->wait.lock, flags);
tsk->state = TASK_UNINTERRUPTIBLE;
}
remove_wait_queue_locked(&sem->wait, &wait);
wake_up_locked(&sem->wait);
spin_unlock_irqrestore(&sem->wait.lock, flags);
tsk->state = TASK_RUNNING;
}
asmlinkage int __sched __down_interruptible(struct semaphore * sem)
{
int retval = 0;
struct task_struct *tsk = current;
DECLARE_WAITQUEUE(wait, tsk);
unsigned long flags;
tsk->state = TASK_INTERRUPTIBLE;
spin_lock_irqsave(&sem->wait.lock, flags);
add_wait_queue_exclusive_locked(&sem->wait, &wait);
sem->sleepers++;
for (;;) {
int sleepers = sem->sleepers;
/*
* With signals pending, this turns into
* the trylock failure case - we won't be
* sleeping, and we* can't get the lock as
* it has contention. Just correct the count
* and exit.
*/
if (signal_pending(current)) {
retval = -EINTR;
sem->sleepers = 0;
atomic_add(sleepers, &sem->count);
break;
}
/*
* Add "everybody else" into it. They aren't
* playing, because we own the spinlock in
* wait_queue_head. The "-1" is because we're
* still hoping to get the semaphore.
*/
if (!atomic_add_negative(sleepers - 1, &sem->count)) {
sem->sleepers = 0;
break;
}
sem->sleepers = 1; /* us - see -1 above */
spin_unlock_irqrestore(&sem->wait.lock, flags);
schedule();
spin_lock_irqsave(&sem->wait.lock, flags);
tsk->state = TASK_INTERRUPTIBLE;
}
remove_wait_queue_locked(&sem->wait, &wait);
wake_up_locked(&sem->wait);
spin_unlock_irqrestore(&sem->wait.lock, flags);
tsk->state = TASK_RUNNING;
return retval;
}
/*
* Trylock failed - make sure we correct for
* having decremented the count.
*
* We could have done the trylock with a
* single "cmpxchg" without failure cases,
* but then it wouldn't work on a 386.
*/
asmlinkage int __down_trylock(struct semaphore * sem)
{
int sleepers;
unsigned long flags;
spin_lock_irqsave(&sem->wait.lock, flags);
sleepers = sem->sleepers + 1;
sem->sleepers = 0;
/*
* Add "everybody else" and us into it. They aren't
* playing, because we own the spinlock in the
* wait_queue_head.
*/
if (!atomic_add_negative(sleepers, &sem->count)) {
wake_up_locked(&sem->wait);
}
spin_unlock_irqrestore(&sem->wait.lock, flags);
return 1;
}
arch/m68k/kernel/Makefile
View file @ 64ac24e7
......@@ -10,7 +10,7 @@ endif
extra-y += vmlinux.lds
obj-y := entry.o process.o traps.o ints.o signal.o ptrace.o module.o \
sys_m68k.o time.o semaphore.o setup.o m68k_ksyms.o devres.o
sys_m68k.o time.o setup.o m68k_ksyms.o devres.o
devres-y = ../../../kernel/irq/devres.o
......
arch/m68k/kernel/m68k_ksyms.c
View file @ 64ac24e7
#include <linux/module.h>
#include <asm/semaphore.h>
asmlinkage long long __ashldi3 (long long, int);
asmlinkage long long __ashrdi3 (long long, int);
......@@ -15,8 +14,3 @@ EXPORT_SYMBOL(__ashrdi3);
EXPORT_SYMBOL(__lshrdi3);
EXPORT_SYMBOL(__muldi3);
EXPORT_SYMBOL(__down_failed);
EXPORT_SYMBOL(__down_failed_interruptible);
EXPORT_SYMBOL(__down_failed_trylock);
EXPORT_SYMBOL(__up_wakeup);
arch/m68k/kernel/semaphore.c deleted 100644 → 0
View file @ e48b3dee
/*
* Generic semaphore code. Buyer beware. Do your own
* specific changes in <asm/semaphore-helper.h>
*/
#include <linux/sched.h>
#include <linux/init.h>
#include <asm/semaphore-helper.h>
#ifndef CONFIG_RMW_INSNS
spinlock_t semaphore_wake_lock;
#endif
/*
* Semaphores are implemented using a two-way counter:
* The "count" variable is decremented for each process
* that tries to sleep, while the "waking" variable is
* incremented when the "up()" code goes to wake up waiting
* processes.
*
* Notably, the inline "up()" and "down()" functions can
* efficiently test if they need to do any extra work (up
* needs to do something only if count was negative before
* the increment operation.
*
* waking_non_zero() (from asm/semaphore.h) must execute
* atomically.
*
* When __up() is called, the count was negative before
* incrementing it, and we need to wake up somebody.
*
* This routine adds one to the count of processes that need to
* wake up and exit. ALL waiting processes actually wake up but
* only the one that gets to the "waking" field first will gate
* through and acquire the semaphore. The others will go back
* to sleep.
*
* Note that these functions are only called when there is
* contention on the lock, and as such all this is the
* "non-critical" part of the whole semaphore business. The
* critical part is the inline stuff in <asm/semaphore.h>
* where we want to avoid any extra jumps and calls.
*/
void __up(struct semaphore *sem)
{
wake_one_more(sem);
wake_up(&sem->wait);
}
/*
* Perform the "down" function. Return zero for semaphore acquired,
* return negative for signalled out of the function.
*
* If called from __down, the return is ignored and the wait loop is
* not interruptible. This means that a task waiting on a semaphore
* using "down()" cannot be killed until someone does an "up()" on
* the semaphore.
*
* If called from __down_interruptible, the return value gets checked
* upon return. If the return value is negative then the task continues
* with the negative value in the return register (it can be tested by
* the caller).
*
* Either form may be used in conjunction with "up()".
*
*/
#define DOWN_HEAD(task_state) \
\
\
current->state = (task_state); \
add_wait_queue(&sem->wait, &wait); \
\
/* \
* Ok, we're set up. sem->count is known to be less than zero \
* so we must wait. \
* \
* We can let go the lock for purposes of waiting. \
* We re-acquire it after awaking so as to protect \
* all semaphore operations. \
* \
* If "up()" is called before we call waking_non_zero() then \
* we will catch it right away. If it is called later then \
* we will have to go through a wakeup cycle to catch it. \
* \
* Multiple waiters contend for the semaphore lock to see \
* who gets to gate through and who has to wait some more. \
*/ \
for (;;) {
#define DOWN_TAIL(task_state) \
current->state = (task_state); \
} \
current->state = TASK_RUNNING; \
remove_wait_queue(&sem->wait, &wait);
void __sched __down(struct semaphore * sem)
{
DECLARE_WAITQUEUE(wait, current);
DOWN_HEAD(TASK_UNINTERRUPTIBLE)
if (waking_non_zero(sem))
break;
schedule();
DOWN_TAIL(TASK_UNINTERRUPTIBLE)
}
int __sched __down_interruptible(struct semaphore * sem)
{
DECLARE_WAITQUEUE(wait, current);
int ret = 0;
DOWN_HEAD(TASK_INTERRUPTIBLE)
ret = waking_non_zero_interruptible(sem, current);
if (ret)
{
if (ret == 1)
/* ret != 0 only if we get interrupted -arca */
ret = 0;
break;
}
schedule();
DOWN_TAIL(TASK_INTERRUPTIBLE)
return ret;
}
int __down_trylock(struct semaphore * sem)
{
return waking_non_zero_trylock(sem);
}
arch/m68k/lib/Makefile
View file @ 64ac24e7
......@@ -5,4 +5,4 @@
EXTRA_AFLAGS := -traditional
lib-y := ashldi3.o ashrdi3.o lshrdi3.o muldi3.o \
checksum.o string.o semaphore.o uaccess.o
checksum.o string.o uaccess.o
arch/m68k/lib/semaphore.S deleted 100644 → 0
View file @ e48b3dee
/*
* linux/arch/m68k/lib/semaphore.S
*
* Copyright (C) 1996 Linus Torvalds
*
* m68k version by Andreas Schwab
*/
#include <linux/linkage.h>
#include <asm/semaphore.h>
/*
* The semaphore operations have a special calling sequence that
* allow us to do a simpler in-line version of them. These routines
* need to convert that sequence back into the C sequence when
* there is contention on the semaphore.
*/
ENTRY(__down_failed)
moveml %a0/%d0/%d1,-(%sp)
movel %a1,-(%sp)
jbsr __down
movel (%sp)+,%a1
moveml (%sp)+,%a0/%d0/%d1
rts
ENTRY(__down_failed_interruptible)
movel %a0,-(%sp)
movel %d1,-(%sp)
movel %a1,-(%sp)
jbsr __down_interruptible
movel (%sp)+,%a1
movel (%sp)+,%d1
movel (%sp)+,%a0
rts
ENTRY(__down_failed_trylock)
movel %a0,-(%sp)
movel %d1,-(%sp)
movel %a1,-(%sp)
jbsr __down_trylock
movel (%sp)+,%a1
movel (%sp)+,%d1
movel (%sp)+,%a0
rts
ENTRY(__up_wakeup)
moveml %a0/%d0/%d1,-(%sp)
movel %a1,-(%sp)
jbsr __up
movel (%sp)+,%a1
moveml (%sp)+,%a0/%d0/%d1
rts
arch/m68knommu/kernel/Makefile
View file @ 64ac24e7
......@@ -5,7 +5,7 @@
extra-y := vmlinux.lds
obj-y += dma.o entry.o init_task.o irq.o m68k_ksyms.o process.o ptrace.o \
semaphore.o setup.o signal.o syscalltable.o sys_m68k.o time.o traps.o
setup.o signal.o syscalltable.o sys_m68k.o time.o traps.o
obj-$(CONFIG_MODULES) += module.o
obj-$(CONFIG_COMEMPCI) += comempci.o
arch/m68knommu/kernel/m68k_ksyms.c
View file @ 64ac24e7
......@@ -13,7 +13,6 @@
#include <asm/pgalloc.h>
#include <asm/irq.h>
#include <asm/io.h>
#include <asm/semaphore.h>
#include <asm/checksum.h>
#include <asm/current.h>
......@@ -39,11 +38,6 @@ EXPORT_SYMBOL(csum_partial_copy_nocheck);
EXPORT_SYMBOL(memcpy);
EXPORT_SYMBOL(memset);
EXPORT_SYMBOL(__down_failed);
EXPORT_SYMBOL(__down_failed_interruptible);
EXPORT_SYMBOL(__down_failed_trylock);
EXPORT_SYMBOL(__up_wakeup);
/*
* libgcc functions - functions that are used internally by the
* compiler... (prototypes are not correct though, but that
......
arch/m68knommu/kernel/semaphore.c deleted 100644 → 0
View file @ e48b3dee
/*
* Generic semaphore code. Buyer beware. Do your own
* specific changes in <asm/semaphore-helper.h>
*/
#include <linux/sched.h>
#include <linux/err.h>
#include <linux/init.h>
#include <asm/semaphore-helper.h>
#ifndef CONFIG_RMW_INSNS
spinlock_t semaphore_wake_lock;
#endif
/*
* Semaphores are implemented using a two-way counter:
* The "count" variable is decremented for each process
* that tries to sleep, while the "waking" variable is
* incremented when the "up()" code goes to wake up waiting
* processes.
*
* Notably, the inline "up()" and "down()" functions can
* efficiently test if they need to do any extra work (up
* needs to do something only if count was negative before
* the increment operation.
*
* waking_non_zero() (from asm/semaphore.h) must execute
* atomically.
*
* When __up() is called, the count was negative before
* incrementing it, and we need to wake up somebody.
*
* This routine adds one to the count of processes that need to
* wake up and exit. ALL waiting processes actually wake up but
* only the one that gets to the "waking" field first will gate
* through and acquire the semaphore. The others will go back
* to sleep.
*
* Note that these functions are only called when there is
* contention on the lock, and as such all this is the
* "non-critical" part of the whole semaphore business. The
* critical part is the inline stuff in <asm/semaphore.h>
* where we want to avoid any extra jumps and calls.
*/
void __up(struct semaphore *sem)
{
wake_one_more(sem);
wake_up(&sem->wait);
}
/*
* Perform the "down" function. Return zero for semaphore acquired,
* return negative for signalled out of the function.
*
* If called from __down, the return is ignored and the wait loop is
* not interruptible. This means that a task waiting on a semaphore
* using "down()" cannot be killed until someone does an "up()" on
* the semaphore.
*
* If called from __down_interruptible, the return value gets checked
* upon return. If the return value is negative then the task continues
* with the negative value in the return register (it can be tested by
* the caller).
*
* Either form may be used in conjunction with "up()".
*
*/
#define DOWN_HEAD(task_state) \
\
\
current->state = (task_state); \
add_wait_queue(&sem->wait, &wait); \
\
/* \
* Ok, we're set up. sem->count is known to be less than zero \
* so we must wait. \
* \
* We can let go the lock for purposes of waiting. \
* We re-acquire it after awaking so as to protect \
* all semaphore operations. \
* \
* If "up()" is called before we call waking_non_zero() then \
* we will catch it right away. If it is called later then \
* we will have to go through a wakeup cycle to catch it. \
* \
* Multiple waiters contend for the semaphore lock to see \
* who gets to gate through and who has to wait some more. \
*/ \
for (;;) {
#define DOWN_TAIL(task_state) \
current->state = (task_state); \
} \
current->state = TASK_RUNNING; \
remove_wait_queue(&sem->wait, &wait);
void __sched __down(struct semaphore * sem)
{
DECLARE_WAITQUEUE(wait, current);
DOWN_HEAD(TASK_UNINTERRUPTIBLE)
if (waking_non_zero(sem))
break;
schedule();
DOWN_TAIL(TASK_UNINTERRUPTIBLE)
}
int __sched __down_interruptible(struct semaphore * sem)
{
DECLARE_WAITQUEUE(wait, current);
int ret = 0;
DOWN_HEAD(TASK_INTERRUPTIBLE)
ret = waking_non_zero_interruptible(sem, current);
if (ret)
{
if (ret == 1)
/* ret != 0 only if we get interrupted -arca */
ret = 0;
break;
}
schedule();
DOWN_TAIL(TASK_INTERRUPTIBLE)
return ret;
}
int __down_trylock(struct semaphore * sem)
{
return waking_non_zero_trylock(sem);
}
arch/m68knommu/lib/Makefile
View file @ 64ac24e7
......@@ -4,4 +4,4 @@
lib-y := ashldi3.o ashrdi3.o lshrdi3.o \
muldi3.o mulsi3.o divsi3.o udivsi3.o modsi3.o umodsi3.o \
checksum.o semaphore.o memcpy.o memset.o delay.o
checksum.o memcpy.o memset.o delay.o
arch/m68knommu/lib/semaphore.S deleted 100644 → 0
View file @ e48b3dee
/*
* linux/arch/m68k/lib/semaphore.S
*
* Copyright (C) 1996 Linus Torvalds
*
* m68k version by Andreas Schwab
*
* MAR/1999 -- modified to support ColdFire (gerg@snapgear.com)
*/
#include <linux/linkage.h>
#include <asm/semaphore.h>
/*
* "down_failed" is called with the eventual return address
* in %a0, and the address of the semaphore in %a1. We need
* to increment the number of waiters on the semaphore,
* call "__down()", and then eventually return to try again.
*/
ENTRY(__down_failed)
#ifdef CONFIG_COLDFIRE
subl #12,%sp
moveml %a0/%d0/%d1,(%sp)
#else
moveml %a0/%d0/%d1,-(%sp)
#endif
movel %a1,-(%sp)
jbsr __down
movel (%sp)+,%a1
movel (%sp)+,%d0
movel (%sp)+,%d1
rts
ENTRY(__down_failed_interruptible)
movel %a0,-(%sp)
movel %d1,-(%sp)
movel %a1,-(%sp)
jbsr __down_interruptible
movel (%sp)+,%a1
movel (%sp)+,%d1
rts
ENTRY(__up_wakeup)
#ifdef CONFIG_COLDFIRE
subl #12,%sp
moveml %a0/%d0/%d1,(%sp)
#else
moveml %a0/%d0/%d1,-(%sp)
#endif
movel %a1,-(%sp)
jbsr __up
movel (%sp)+,%a1
movel (%sp)+,%d0
movel (%sp)+,%d1
rts
ENTRY(__down_failed_trylock)
movel %a0,-(%sp)
movel %d1,-(%sp)
movel %a1,-(%sp)
jbsr __down_trylock
movel (%sp)+,%a1
movel (%sp)+,%d1
movel (%sp)+,%a0
rts
arch/mips/kernel/Makefile
View file @ 64ac24e7
......@@ -5,7 +5,7 @@
extra-y := head.o init_task.o vmlinux.lds
obj-y += cpu-probe.o branch.o entry.o genex.o irq.o process.o \
ptrace.o reset.o semaphore.o setup.o signal.o syscall.o \
ptrace.o reset.o setup.o signal.o syscall.o \
time.o topology.o traps.o unaligned.o
obj-$(CONFIG_CEVT_BCM1480) += cevt-bcm1480.o
......
arch/mips/kernel/semaphore.c deleted 100644 → 0
View file @ e48b3dee
/*
* MIPS-specific semaphore code.
*
* Copyright (C) 1999 Cort Dougan <cort@cs.nmt.edu>
* Copyright (C) 2004 Ralf Baechle <ralf@linux-mips.org>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* April 2001 - Reworked by Paul Mackerras <paulus@samba.org>
* to eliminate the SMP races in the old version between the updates
* of `count' and `waking'. Now we use negative `count' values to
* indicate that some process(es) are waiting for the semaphore.
*/
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/init.h>
#include <asm/atomic.h>
#include <asm/cpu-features.h>
#include <asm/errno.h>
#include <asm/semaphore.h>
#include <asm/war.h>
/*
* Atomically update sem->count.
* This does the equivalent of the following:
*
* old_count = sem->count;
* tmp = MAX(old_count, 0) + incr;
* sem->count = tmp;
* return old_count;
*
* On machines without lld/scd we need a spinlock to make the manipulation of
* sem->count and sem->waking atomic. Scalability isn't an issue because
* this lock is used on UP only so it's just an empty variable.
*/
static inline int __sem_update_count(struct semaphore *sem, int incr)
{
int old_count, tmp;
if (cpu_has_llsc && R10000_LLSC_WAR) {
__asm__ __volatile__(
" .set mips3 \n"
"1: ll %0, %2 # __sem_update_count \n"
" sra %1, %0, 31 \n"
" not %1 \n"
" and %1, %0, %1 \n"
" addu %1, %1, %3 \n"
" sc %1, %2 \n"
" beqzl %1, 1b \n"
" .set mips0 \n"
: "=&r" (old_count), "=&r" (tmp), "=m" (sem->count)
: "r" (incr), "m" (sem->count));
} else if (cpu_has_llsc) {
__asm__ __volatile__(
" .set mips3 \n"
"1: ll %0, %2 # __sem_update_count \n"
" sra %1, %0, 31 \n"
" not %1 \n"
" and %1, %0, %1 \n"
" addu %1, %1, %3 \n"
" sc %1, %2 \n"
" beqz %1, 1b \n"
" .set mips0 \n"
: "=&r" (old_count), "=&r" (tmp), "=m" (sem->count)
: "r" (incr), "m" (sem->count));
} else {
static DEFINE_SPINLOCK(semaphore_lock);
unsigned long flags;
spin_lock_irqsave(&semaphore_lock, flags);
old_count = atomic_read(&sem->count);
tmp = max_t(int, old_count, 0) + incr;
atomic_set(&sem->count, tmp);
spin_unlock_irqrestore(&semaphore_lock, flags);
}
return old_count;
}
void __up(struct semaphore *sem)
{
/*
* Note that we incremented count in up() before we came here,
* but that was ineffective since the result was <= 0, and
* any negative value of count is equivalent to 0.
* This ends up setting count to 1, unless count is now > 0
* (i.e. because some other cpu has called up() in the meantime),
* in which case we just increment count.
*/
__sem_update_count(sem, 1);
wake_up(&sem->wait);
}
EXPORT_SYMBOL(__up);
/*
* Note that when we come in to __down or __down_interruptible,
* we have already decremented count, but that decrement was
* ineffective since the result was < 0, and any negative value
* of count is equivalent to 0.
* Thus it is only when we decrement count from some value > 0
* that we have actually got the semaphore.
*/
void __sched __down(struct semaphore *sem)
{
struct task_struct *tsk = current;
DECLARE_WAITQUEUE(wait, tsk);
__set_task_state(tsk, TASK_UNINTERRUPTIBLE);
add_wait_queue_exclusive(&sem->wait, &wait);
/*
* Try to get the semaphore. If the count is > 0, then we've
* got the semaphore; we decrement count and exit the loop.
* If the count is 0 or negative, we set it to -1, indicating
* that we are asleep, and then sleep.
*/
while (__sem_update_count(sem, -1) <= 0) {
schedule();
set_task_state(tsk, TASK_UNINTERRUPTIBLE);
}
remove_wait_queue(&sem->wait, &wait);
__set_task_state(tsk, TASK_RUNNING);
/*
* If there are any more sleepers, wake one of them up so
* that it can either get the semaphore, or set count to -1
* indicating that there are still processes sleeping.
*/
wake_up(&sem->wait);
}
EXPORT_SYMBOL(__down);
int __sched __down_interruptible(struct semaphore * sem)
{
int retval = 0;
struct task_struct *tsk = current;
DECLARE_WAITQUEUE(wait, tsk);
__set_task_state(tsk, TASK_INTERRUPTIBLE);
add_wait_queue_exclusive(&sem->wait, &wait);
while (__sem_update_count(sem, -1) <= 0) {
if (signal_pending(current)) {
/*
* A signal is pending - give up trying.
* Set sem->count to 0 if it is negative,
* since we are no longer sleeping.
*/
__sem_update_count(sem, 0);
retval = -EINTR;
break;
}
schedule();
set_task_state(tsk, TASK_INTERRUPTIBLE);
}
remove_wait_queue(&sem->wait, &wait);
__set_task_state(tsk, TASK_RUNNING);
wake_up(&sem->wait);
return retval;
}
EXPORT_SYMBOL(__down_interruptible);
arch/mn10300/kernel/Makefile
View file @ 64ac24e7
......@@ -3,7 +3,7 @@
#
extra-y := head.o init_task.o vmlinux.lds
obj-y := process.o semaphore.o signal.o entry.o fpu.o traps.o irq.o \
obj-y := process.o signal.o entry.o fpu.o traps.o irq.o \
ptrace.o setup.o time.o sys_mn10300.o io.o kthread.o \
switch_to.o mn10300_ksyms.o kernel_execve.o
......
arch/mn10300/kernel/semaphore.c deleted 100644 → 0
View file @ e48b3dee
/* MN10300 Semaphore implementation
*
* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public Licence
* as published by the Free Software Foundation; either version
* 2 of the Licence, or (at your option) any later version.
*/
#include <linux/sched.h>
#include <linux/module.h>
#include <asm/semaphore.h>
struct sem_waiter {
struct list_head list;
struct task_struct *task;
};
#if SEMAPHORE_DEBUG
void semtrace(struct semaphore *sem, const char *str)
{
if (sem->debug)
printk(KERN_DEBUG "[%d] %s({%d,%d})\n",
current->pid,
str,
atomic_read(&sem->count),
list_empty(&sem->wait_list) ? 0 : 1);
}
#else
#define semtrace(SEM, STR) do { } while (0)
#endif
/*
* wait for a token to be granted from a semaphore
* - entered with lock held and interrupts disabled
*/
void __down(struct semaphore *sem, unsigned long flags)
{
struct task_struct *tsk = current;
struct sem_waiter waiter;
semtrace(sem, "Entering __down");
/* set up my own style of waitqueue */
waiter.task = tsk;
get_task_struct(tsk);
list_add_tail(&waiter.list, &sem->wait_list);
/* we don't need to touch the semaphore struct anymore */
spin_unlock_irqrestore(&sem->wait_lock, flags);
/* wait to be given the semaphore */
set_task_state(tsk, TASK_UNINTERRUPTIBLE);
for (;;) {
if (!waiter.task)
break;
schedule();
set_task_state(tsk, TASK_UNINTERRUPTIBLE);
}
tsk->state = TASK_RUNNING;
semtrace(sem, "Leaving __down");
}
EXPORT_SYMBOL(__down);
/*
* interruptibly wait for a token to be granted from a semaphore
* - entered with lock held and interrupts disabled
*/
int __down_interruptible(struct semaphore *sem, unsigned long flags)
{
struct task_struct *tsk = current;
struct sem_waiter waiter;
int ret;
semtrace(sem, "Entering __down_interruptible");
/* set up my own style of waitqueue */
waiter.task = tsk;
get_task_struct(tsk);
list_add_tail(&waiter.list, &sem->wait_list);
/* we don't need to touch the semaphore struct anymore */
set_task_state(tsk, TASK_INTERRUPTIBLE);
spin_unlock_irqrestore(&sem->wait_lock, flags);
/* wait to be given the semaphore */
ret = 0;
for (;;) {
if (!waiter.task)
break;
if (unlikely(signal_pending(current)))
goto interrupted;
schedule();
set_task_state(tsk, TASK_INTERRUPTIBLE);
}
out:
tsk->state = TASK_RUNNING;
semtrace(sem, "Leaving __down_interruptible");
return ret;
interrupted:
spin_lock_irqsave(&sem->wait_lock, flags);
list_del(&waiter.list);
spin_unlock_irqrestore(&sem->wait_lock, flags);
ret = 0;
if (!waiter.task) {
put_task_struct(current);
ret = -EINTR;
}
goto out;
}
EXPORT_SYMBOL(__down_interruptible);
/*
* release a single token back to a semaphore
* - entered with lock held and interrupts disabled
*/
void __up(struct semaphore *sem)
{
struct task_struct *tsk;
struct sem_waiter *waiter;
semtrace(sem, "Entering __up");
/* grant the token to the process at the front of the queue */
waiter = list_entry(sem->wait_list.next, struct sem_waiter, list);
/* We must be careful not to touch 'waiter' after we set ->task = NULL.
* It is an allocated on the waiter's stack and may become invalid at
* any time after that point (due to a wakeup from another source).
*/
list_del_init(&waiter->list);
tsk = waiter->task;
smp_mb();
waiter->task = NULL;
wake_up_process(tsk);
put_task_struct(tsk);
semtrace(sem, "Leaving __up");
}
EXPORT_SYMBOL(__up);
arch/parisc/kernel/Makefile
View file @ 64ac24e7
......@@ -9,7 +9,7 @@ AFLAGS_pacache.o := -traditional
obj-y := cache.o pacache.o setup.o traps.o time.o irq.o \
pa7300lc.o syscall.o entry.o sys_parisc.o firmware.o \
ptrace.o hardware.o inventory.o drivers.o semaphore.o \
ptrace.o hardware.o inventory.o drivers.o \
signal.o hpmc.o real2.o parisc_ksyms.o unaligned.o \
process.o processor.o pdc_cons.o pdc_chassis.o unwind.o \
topology.o
......
arch/parisc/kernel/parisc_ksyms.c
View file @ 64ac24e7
......@@ -69,11 +69,6 @@ EXPORT_SYMBOL(memcpy_toio);
EXPORT_SYMBOL(memcpy_fromio);
EXPORT_SYMBOL(memset_io);
#include <asm/semaphore.h>
EXPORT_SYMBOL(__up);
EXPORT_SYMBOL(__down_interruptible);
EXPORT_SYMBOL(__down);
extern void $$divI(void);
extern void $$divU(void);
extern void $$remI(void);
......
arch/parisc/kernel/semaphore.c deleted 100644 → 0
View file @ e48b3dee
/*
* Semaphore implementation Copyright (c) 2001 Matthew Wilcox, Hewlett-Packard
*/
#include <linux/sched.h>
#include <linux/spinlock.h>
#include <linux/errno.h>
#include <linux/init.h>
/*
* Semaphores are complex as we wish to avoid using two variables.
* `count' has multiple roles, depending on its value. If it is positive
* or zero, there are no waiters. The functions here will never be
* called; see <asm/semaphore.h>
*
* When count is -1 it indicates there is at least one task waiting
* for the semaphore.
*
* When count is less than that, there are '- count - 1' wakeups
* pending. ie if it has value -3, there are 2 wakeups pending.
*
* Note that these functions are only called when there is contention
* on the lock, and as such all this is the "non-critical" part of the
* whole semaphore business. The critical part is the inline stuff in
* <asm/semaphore.h> where we want to avoid any extra jumps and calls.
*/
void __up(struct semaphore *sem)
{
sem->count--;
wake_up(&sem->wait);
}
#define wakers(count) (-1 - count)
#define DOWN_HEAD \
int ret = 0; \
DECLARE_WAITQUEUE(wait, current); \
\
/* Note that someone is waiting */ \
if (sem->count == 0) \
sem->count = -1; \
\
/* protected by the sentry still -- use unlocked version */ \
wait.flags = WQ_FLAG_EXCLUSIVE; \
__add_wait_queue_tail(&sem->wait, &wait); \
lost_race: \
spin_unlock_irq(&sem->sentry); \
#define DOWN_TAIL \
spin_lock_irq(&sem->sentry); \
if (wakers(sem->count) == 0 && ret == 0) \
goto lost_race; /* Someone stole our wakeup */ \
__remove_wait_queue(&sem->wait, &wait); \
current->state = TASK_RUNNING; \
if (!waitqueue_active(&sem->wait) && (sem->count < 0)) \
sem->count = wakers(sem->count);
#define UPDATE_COUNT \
sem->count += (sem->count < 0) ? 1 : - 1;
void __sched __down(struct semaphore * sem)
{
DOWN_HEAD
for(;;) {
set_task_state(current, TASK_UNINTERRUPTIBLE);
/* we can _read_ this without the sentry */
if (sem->count != -1)
break;
schedule();
}
DOWN_TAIL
UPDATE_COUNT
}
int __sched __down_interruptible(struct semaphore * sem)
{
DOWN_HEAD
for(;;) {
set_task_state(current, TASK_INTERRUPTIBLE);
/* we can _read_ this without the sentry */
if (sem->count != -1)
break;
if (signal_pending(current)) {
ret = -EINTR;
break;
}
schedule();
}
DOWN_TAIL
if (!ret) {
UPDATE_COUNT
}
return ret;
}
arch/powerpc/kernel/Makefile
View file @ 64ac24e7
......@@ -12,7 +12,7 @@ CFLAGS_prom_init.o += -fPIC
CFLAGS_btext.o += -fPIC
endif
obj-y := semaphore.o cputable.o ptrace.o syscalls.o \
obj-y := cputable.o ptrace.o syscalls.o \
irq.o align.o signal_32.o pmc.o vdso.o \
init_task.o process.o systbl.o idle.o \
signal.o
......
arch/powerpc/kernel/ppc_ksyms.c
View file @ 64ac24e7
......@@ -15,7 +15,6 @@
#include <linux/bitops.h>
#include <asm/page.h>
#include <asm/semaphore.h>
#include <asm/processor.h>
#include <asm/cacheflush.h>
#include <asm/uaccess.h>
......
arch/powerpc/kernel/semaphore.c deleted 100644 → 0
View file @ e48b3dee
/*
* PowerPC-specific semaphore code.
*
* Copyright (C) 1999 Cort Dougan <cort@cs.nmt.edu>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* April 2001 - Reworked by Paul Mackerras <paulus@samba.org>
* to eliminate the SMP races in the old version between the updates
* of `count' and `waking'. Now we use negative `count' values to
* indicate that some process(es) are waiting for the semaphore.
*/
#include <linux/sched.h>
#include <linux/init.h>
#include <linux/module.h>
#include <asm/atomic.h>
#include <asm/semaphore.h>
#include <asm/errno.h>
/*
* Atomically update sem->count.
* This does the equivalent of the following:
*
* old_count = sem->count;
* tmp = MAX(old_count, 0) + incr;
* sem->count = tmp;
* return old_count;
*/
static inline int __sem_update_count(struct semaphore *sem, int incr)
{
int old_count, tmp;
__asm__ __volatile__("\n"
"1: lwarx %0,0,%3\n"
" srawi %1,%0,31\n"
" andc %1,%0,%1\n"
" add %1,%1,%4\n"
PPC405_ERR77(0,%3)
" stwcx. %1,0,%3\n"
" bne 1b"
: "=&r" (old_count), "=&r" (tmp), "=m" (sem->count)
: "r" (&sem->count), "r" (incr), "m" (sem->count)
: "cc");
return old_count;
}
void __up(struct semaphore *sem)
{
/*
* Note that we incremented count in up() before we came here,
* but that was ineffective since the result was <= 0, and
* any negative value of count is equivalent to 0.
* This ends up setting count to 1, unless count is now > 0
* (i.e. because some other cpu has called up() in the meantime),
* in which case we just increment count.
*/
__sem_update_count(sem, 1);
wake_up(&sem->wait);
}
EXPORT_SYMBOL(__up);
/*
* Note that when we come in to __down or __down_interruptible,
* we have already decremented count, but that decrement was
* ineffective since the result was < 0, and any negative value
* of count is equivalent to 0.
* Thus it is only when we decrement count from some value > 0
* that we have actually got the semaphore.
*/
void __sched __down(struct semaphore *sem)
{
struct task_struct *tsk = current;
DECLARE_WAITQUEUE(wait, tsk);
__set_task_state(tsk, TASK_UNINTERRUPTIBLE);
add_wait_queue_exclusive(&sem->wait, &wait);
/*
* Try to get the semaphore. If the count is > 0, then we've
* got the semaphore; we decrement count and exit the loop.
* If the count is 0 or negative, we set it to -1, indicating
* that we are asleep, and then sleep.
*/
while (__sem_update_count(sem, -1) <= 0) {
schedule();
set_task_state(tsk, TASK_UNINTERRUPTIBLE);
}
remove_wait_queue(&sem->wait, &wait);
__set_task_state(tsk, TASK_RUNNING);
/*
* If there are any more sleepers, wake one of them up so
* that it can either get the semaphore, or set count to -1
* indicating that there are still processes sleeping.
*/
wake_up(&sem->wait);
}
EXPORT_SYMBOL(__down);
int __sched __down_interruptible(struct semaphore * sem)
{
int retval = 0;
struct task_struct *tsk = current;
DECLARE_WAITQUEUE(wait, tsk);
__set_task_state(tsk, TASK_INTERRUPTIBLE);
add_wait_queue_exclusive(&sem->wait, &wait);
while (__sem_update_count(sem, -1) <= 0) {
if (signal_pending(current)) {
/*
* A signal is pending - give up trying.
* Set sem->count to 0 if it is negative,
* since we are no longer sleeping.
*/
__sem_update_count(sem, 0);
retval = -EINTR;
break;
}
schedule();
set_task_state(tsk, TASK_INTERRUPTIBLE);
}
remove_wait_queue(&sem->wait, &wait);
__set_task_state(tsk, TASK_RUNNING);
wake_up(&sem->wait);
return retval;
}
EXPORT_SYMBOL(__down_interruptible);
arch/ppc/kernel/semaphore.c deleted 100644 → 0
View file @ e48b3dee
/*
* PowerPC-specific semaphore code.
*
* Copyright (C) 1999 Cort Dougan <cort@cs.nmt.edu>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* April 2001 - Reworked by Paul Mackerras <paulus@samba.org>
* to eliminate the SMP races in the old version between the updates
* of `count' and `waking'. Now we use negative `count' values to
* indicate that some process(es) are waiting for the semaphore.
*/
#include <linux/sched.h>
#include <linux/init.h>
#include <asm/atomic.h>
#include <asm/semaphore.h>
#include <asm/errno.h>
/*
* Atomically update sem->count.
* This does the equivalent of the following:
*
* old_count = sem->count;
* tmp = MAX(old_count, 0) + incr;
* sem->count = tmp;
* return old_count;
*/
static inline int __sem_update_count(struct semaphore *sem, int incr)
{
int old_count, tmp;
__asm__ __volatile__("\n"
"1: lwarx %0,0,%3\n"
" srawi %1,%0,31\n"
" andc %1,%0,%1\n"
" add %1,%1,%4\n"
PPC405_ERR77(0,%3)
" stwcx. %1,0,%3\n"
" bne 1b"
: "=&r" (old_count), "=&r" (tmp), "=m" (sem->count)
: "r" (&sem->count), "r" (incr), "m" (sem->count)
: "cc");
return old_count;
}
void __up(struct semaphore *sem)
{
/*
* Note that we incremented count in up() before we came here,
* but that was ineffective since the result was <= 0, and
* any negative value of count is equivalent to 0.
* This ends up setting count to 1, unless count is now > 0
* (i.e. because some other cpu has called up() in the meantime),
* in which case we just increment count.
*/
__sem_update_count(sem, 1);
wake_up(&sem->wait);
}
/*
* Note that when we come in to __down or __down_interruptible,
* we have already decremented count, but that decrement was
* ineffective since the result was < 0, and any negative value
* of count is equivalent to 0.
* Thus it is only when we decrement count from some value > 0
* that we have actually got the semaphore.
*/
void __sched __down(struct semaphore *sem)
{
struct task_struct *tsk = current;
DECLARE_WAITQUEUE(wait, tsk);
tsk->state = TASK_UNINTERRUPTIBLE;
add_wait_queue_exclusive(&sem->wait, &wait);
smp_wmb();
/*
* Try to get the semaphore. If the count is > 0, then we've
* got the semaphore; we decrement count and exit the loop.
* If the count is 0 or negative, we set it to -1, indicating
* that we are asleep, and then sleep.
*/
while (__sem_update_count(sem, -1) <= 0) {
schedule();
tsk->state = TASK_UNINTERRUPTIBLE;
}
remove_wait_queue(&sem->wait, &wait);
tsk->state = TASK_RUNNING;
/*
* If there are any more sleepers, wake one of them up so
* that it can either get the semaphore, or set count to -1
* indicating that there are still processes sleeping.
*/
wake_up(&sem->wait);
}
int __sched __down_interruptible(struct semaphore * sem)
{
int retval = 0;
struct task_struct *tsk = current;
DECLARE_WAITQUEUE(wait, tsk);
tsk->state = TASK_INTERRUPTIBLE;
add_wait_queue_exclusive(&sem->wait, &wait);
smp_wmb();
while (__sem_update_count(sem, -1) <= 0) {
if (signal_pending(current)) {
/*
* A signal is pending - give up trying.
* Set sem->count to 0 if it is negative,
* since we are no longer sleeping.
*/
__sem_update_count(sem, 0);
retval = -EINTR;
break;
}
schedule();
tsk->state = TASK_INTERRUPTIBLE;
}
tsk->state = TASK_RUNNING;
remove_wait_queue(&sem->wait, &wait);
wake_up(&sem->wait);
return retval;
}
arch/s390/kernel/Makefile
View file @ 64ac24e7
......@@ -11,7 +11,7 @@ CFLAGS_smp.o := -Wno-nonnull
obj-y := bitmap.o traps.o time.o process.o base.o early.o \
setup.o sys_s390.o ptrace.o signal.o cpcmd.o ebcdic.o \
semaphore.o s390_ext.o debug.o irq.o ipl.o dis.o diag.o
s390_ext.o debug.o irq.o ipl.o dis.o diag.o
obj-y += $(if $(CONFIG_64BIT),entry64.o,entry.o)
obj-y += $(if $(CONFIG_64BIT),reipl64.o,reipl.o)
......
arch/s390/kernel/s390_ksyms.c
View file @ 64ac24e7
......@@ -26,13 +26,6 @@ EXPORT_SYMBOL(_ni_bitmap);
EXPORT_SYMBOL(_zb_findmap);
EXPORT_SYMBOL(_sb_findmap);
/*
* semaphore ops
*/
EXPORT_SYMBOL(__up);
EXPORT_SYMBOL(__down);
EXPORT_SYMBOL(__down_interruptible);
/*
* binfmt_elf loader
*/
......
arch/s390/kernel/semaphore.c deleted 100644 → 0
View file @ e48b3dee
/*
* linux/arch/s390/kernel/semaphore.c
*
* S390 version
* Copyright (C) 1998-2000 IBM Corporation
* Author(s): Martin Schwidefsky
*
* Derived from "linux/arch/i386/kernel/semaphore.c
* Copyright (C) 1999, Linus Torvalds
*
*/
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <asm/semaphore.h>
/*
* Atomically update sem->count. Equivalent to:
* old_val = sem->count.counter;
* new_val = ((old_val >= 0) ? old_val : 0) + incr;
* sem->count.counter = new_val;
* return old_val;
*/
static inline int __sem_update_count(struct semaphore *sem, int incr)
{
int old_val, new_val;
asm volatile(
" l %0,0(%3)\n"
"0: ltr %1,%0\n"
" jhe 1f\n"
" lhi %1,0\n"
"1: ar %1,%4\n"
" cs %0,%1,0(%3)\n"
" jl 0b\n"
: "=&d" (old_val), "=&d" (new_val), "=m" (sem->count)
: "a" (&sem->count), "d" (incr), "m" (sem->count)
: "cc");
return old_val;
}
/*
* The inline function up() incremented count but the result
* was <= 0. This indicates that some process is waiting on
* the semaphore. The semaphore is free and we'll wake the
* first sleeping process, so we set count to 1 unless some
* other cpu has called up in the meantime in which case
* we just increment count by 1.
*/
void __up(struct semaphore *sem)
{
__sem_update_count(sem, 1);
wake_up(&sem->wait);
}
/*
* The inline function down() decremented count and the result
* was < 0. The wait loop will atomically test and update the
* semaphore counter following the rules:
* count > 0: decrement count, wake up queue and exit.
* count <= 0: set count to -1, go to sleep.
*/
void __sched __down(struct semaphore * sem)
{
struct task_struct *tsk = current;
DECLARE_WAITQUEUE(wait, tsk);
__set_task_state(tsk, TASK_UNINTERRUPTIBLE);
add_wait_queue_exclusive(&sem->wait, &wait);
while (__sem_update_count(sem, -1) <= 0) {
schedule();
set_task_state(tsk, TASK_UNINTERRUPTIBLE);
}
remove_wait_queue(&sem->wait, &wait);
__set_task_state(tsk, TASK_RUNNING);
wake_up(&sem->wait);
}
/*
* Same as __down() with an additional test for signals.
* If a signal is pending the count is updated as follows:
* count > 0: wake up queue and exit.
* count <= 0: set count to 0, wake up queue and exit.
*/
int __sched __down_interruptible(struct semaphore * sem)
{
int retval = 0;
struct task_struct *tsk = current;
DECLARE_WAITQUEUE(wait, tsk);
__set_task_state(tsk, TASK_INTERRUPTIBLE);
add_wait_queue_exclusive(&sem->wait, &wait);
while (__sem_update_count(sem, -1) <= 0) {
if (signal_pending(current)) {
__sem_update_count(sem, 0);
retval = -EINTR;
break;
}
schedule();
set_task_state(tsk, TASK_INTERRUPTIBLE);
}
remove_wait_queue(&sem->wait, &wait);
__set_task_state(tsk, TASK_RUNNING);
wake_up(&sem->wait);
return retval;
}
arch/sh/kernel/Makefile_32
View file @ 64ac24e7
......@@ -5,7 +5,7 @@
extra-y := head_32.o init_task.o vmlinux.lds
obj-y := debugtraps.o io.o io_generic.o irq.o machvec.o process_32.o \
ptrace_32.o semaphore.o setup.o signal_32.o sys_sh.o sys_sh32.o \
ptrace_32.o setup.o signal_32.o sys_sh.o sys_sh32.o \
syscalls_32.o time_32.o topology.o traps.o traps_32.o
obj-y += cpu/ timers/
......
arch/sh/kernel/Makefile_64
View file @ 64ac24e7
extra-y := head_64.o init_task.o vmlinux.lds
obj-y := debugtraps.o io.o io_generic.o irq.o machvec.o process_64.o \
ptrace_64.o semaphore.o setup.o signal_64.o sys_sh.o sys_sh64.o \
ptrace_64.o setup.o signal_64.o sys_sh.o sys_sh64.o \
syscalls_64.o time_64.o topology.o traps.o traps_64.o
obj-y += cpu/ timers/
......
arch/sh/kernel/semaphore.c deleted 100644 → 0
View file @ e48b3dee
/*
* Just taken from alpha implementation.
* This can't work well, perhaps.
*/
/*
* Generic semaphore code. Buyer beware. Do your own
* specific changes in <asm/semaphore-helper.h>
*/
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/wait.h>
#include <linux/init.h>
#include <asm/semaphore.h>
#include <asm/semaphore-helper.h>
DEFINE_SPINLOCK(semaphore_wake_lock);
/*
* Semaphores are implemented using a two-way counter:
* The "count" variable is decremented for each process
* that tries to sleep, while the "waking" variable is
* incremented when the "up()" code goes to wake up waiting
* processes.
*
* Notably, the inline "up()" and "down()" functions can
* efficiently test if they need to do any extra work (up
* needs to do something only if count was negative before
* the increment operation.
*
* waking_non_zero() (from asm/semaphore.h) must execute
* atomically.
*
* When __up() is called, the count was negative before
* incrementing it, and we need to wake up somebody.
*
* This routine adds one to the count of processes that need to
* wake up and exit. ALL waiting processes actually wake up but
* only the one that gets to the "waking" field first will gate
* through and acquire the semaphore. The others will go back
* to sleep.
*
* Note that these functions are only called when there is
* contention on the lock, and as such all this is the
* "non-critical" part of the whole semaphore business. The
* critical part is the inline stuff in <asm/semaphore.h>
* where we want to avoid any extra jumps and calls.
*/
void __up(struct semaphore *sem)
{
wake_one_more(sem);
wake_up(&sem->wait);
}
/*
* Perform the "down" function. Return zero for semaphore acquired,
* return negative for signalled out of the function.
*
* If called from __down, the return is ignored and the wait loop is
* not interruptible. This means that a task waiting on a semaphore
* using "down()" cannot be killed until someone does an "up()" on
* the semaphore.
*
* If called from __down_interruptible, the return value gets checked
* upon return. If the return value is negative then the task continues
* with the negative value in the return register (it can be tested by
* the caller).
*
* Either form may be used in conjunction with "up()".
*
*/
#define DOWN_VAR \
struct task_struct *tsk = current; \
wait_queue_t wait; \
init_waitqueue_entry(&wait, tsk);
#define DOWN_HEAD(task_state) \
\
\
tsk->state = (task_state); \
add_wait_queue(&sem->wait, &wait); \
\
/* \
* Ok, we're set up. sem->count is known to be less than zero \
* so we must wait. \
* \
* We can let go the lock for purposes of waiting. \
* We re-acquire it after awaking so as to protect \
* all semaphore operations. \
* \
* If "up()" is called before we call waking_non_zero() then \
* we will catch it right away. If it is called later then \
* we will have to go through a wakeup cycle to catch it. \
* \
* Multiple waiters contend for the semaphore lock to see \
* who gets to gate through and who has to wait some more. \
*/ \
for (;;) {
#define DOWN_TAIL(task_state) \
tsk->state = (task_state); \
} \
tsk->state = TASK_RUNNING; \
remove_wait_queue(&sem->wait, &wait);
void __sched __down(struct semaphore * sem)
{
DOWN_VAR
DOWN_HEAD(TASK_UNINTERRUPTIBLE)
if (waking_non_zero(sem))
break;
schedule();
DOWN_TAIL(TASK_UNINTERRUPTIBLE)
}
int __sched __down_interruptible(struct semaphore * sem)
{
int ret = 0;
DOWN_VAR
DOWN_HEAD(TASK_INTERRUPTIBLE)
ret = waking_non_zero_interruptible(sem, tsk);
if (ret)
{
if (ret == 1)
/* ret != 0 only if we get interrupted -arca */
ret = 0;
break;
}
schedule();
DOWN_TAIL(TASK_INTERRUPTIBLE)
return ret;
}
int __down_trylock(struct semaphore * sem)
{
return waking_non_zero_trylock(sem);
}
arch/sh/kernel/sh_ksyms_32.c
View file @ 64ac24e7
......@@ -9,7 +9,6 @@
#include <linux/pci.h>
#include <linux/irq.h>
#include <asm/sections.h>
#include <asm/semaphore.h>
#include <asm/processor.h>
#include <asm/uaccess.h>
#include <asm/checksum.h>
......@@ -48,12 +47,6 @@ EXPORT_SYMBOL(__copy_user);
EXPORT_SYMBOL(get_vm_area);
#endif
/* semaphore exports */
EXPORT_SYMBOL(__up);
EXPORT_SYMBOL(__down);
EXPORT_SYMBOL(__down_interruptible);
EXPORT_SYMBOL(__down_trylock);
EXPORT_SYMBOL(__udelay);
EXPORT_SYMBOL(__ndelay);
EXPORT_SYMBOL(__const_udelay);
......
arch/sh/kernel/sh_ksyms_64.c
View file @ 64ac24e7
......@@ -16,7 +16,6 @@
#include <linux/in6.h>
#include <linux/interrupt.h>
#include <linux/screen_info.h>
#include <asm/semaphore.h>
#include <asm/processor.h>
#include <asm/uaccess.h>
#include <asm/checksum.h>
......@@ -37,9 +36,6 @@ EXPORT_SYMBOL(csum_partial_copy_nocheck);
EXPORT_SYMBOL(screen_info);
#endif
EXPORT_SYMBOL(__down);
EXPORT_SYMBOL(__down_trylock);
EXPORT_SYMBOL(__up);
EXPORT_SYMBOL(__put_user_asm_l);
EXPORT_SYMBOL(__get_user_asm_l);
EXPORT_SYMBOL(copy_page);
......
arch/sparc/kernel/Makefile
View file @ 64ac24e7
......@@ -12,7 +12,7 @@ obj-y := entry.o wof.o wuf.o etrap.o rtrap.o traps.o $(IRQ_OBJS) \
sys_sparc.o sunos_asm.o systbls.o \
time.o windows.o cpu.o devices.o sclow.o \
tadpole.o tick14.o ptrace.o sys_solaris.o \
unaligned.o una_asm.o muldiv.o semaphore.o \
unaligned.o una_asm.o muldiv.o \
prom.o of_device.o devres.o
devres-y = ../../../kernel/irq/devres.o
......
arch/sparc/kernel/semaphore.c deleted 100644 → 0
View file @ e48b3dee
/* $Id: semaphore.c,v 1.7 2001/04/18 21:06:05 davem Exp $ */
/* sparc32 semaphore implementation, based on i386 version */
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <asm/semaphore.h>
/*
* Semaphores are implemented using a two-way counter:
* The "count" variable is decremented for each process
* that tries to acquire the semaphore, while the "sleeping"
* variable is a count of such acquires.
*
* Notably, the inline "up()" and "down()" functions can
* efficiently test if they need to do any extra work (up
* needs to do something only if count was negative before
* the increment operation.
*
* "sleeping" and the contention routine ordering is
* protected by the semaphore spinlock.
*
* Note that these functions are only called when there is
* contention on the lock, and as such all this is the
* "non-critical" part of the whole semaphore business. The
* critical part is the inline stuff in <asm/semaphore.h>
* where we want to avoid any extra jumps and calls.
*/
/*
* Logic:
* - only on a boundary condition do we need to care. When we go
* from a negative count to a non-negative, we wake people up.
* - when we go from a non-negative count to a negative do we
* (a) synchronize with the "sleeper" count and (b) make sure
* that we're on the wakeup list before we synchronize so that
* we cannot lose wakeup events.
*/
void __up(struct semaphore *sem)
{
wake_up(&sem->wait);
}
static DEFINE_SPINLOCK(semaphore_lock);
void __sched __down(struct semaphore * sem)
{
struct task_struct *tsk = current;
DECLARE_WAITQUEUE(wait, tsk);
tsk->state = TASK_UNINTERRUPTIBLE;
add_wait_queue_exclusive(&sem->wait, &wait);
spin_lock_irq(&semaphore_lock);
sem->sleepers++;
for (;;) {
int sleepers = sem->sleepers;
/*
* Add "everybody else" into it. They aren't
* playing, because we own the spinlock.
*/
if (!atomic24_add_negative(sleepers - 1, &sem->count)) {
sem->sleepers = 0;
break;
}
sem->sleepers = 1; /* us - see -1 above */
spin_unlock_irq(&semaphore_lock);
schedule();
tsk->state = TASK_UNINTERRUPTIBLE;
spin_lock_irq(&semaphore_lock);
}
spin_unlock_irq(&semaphore_lock);
remove_wait_queue(&sem->wait, &wait);
tsk->state = TASK_RUNNING;
wake_up(&sem->wait);
}
int __sched __down_interruptible(struct semaphore * sem)
{
int retval = 0;
struct task_struct *tsk = current;
DECLARE_WAITQUEUE(wait, tsk);
tsk->state = TASK_INTERRUPTIBLE;
add_wait_queue_exclusive(&sem->wait, &wait);
spin_lock_irq(&semaphore_lock);
sem->sleepers ++;
for (;;) {
int sleepers = sem->sleepers;
/*
* With signals pending, this turns into
* the trylock failure case - we won't be
* sleeping, and we* can't get the lock as
* it has contention. Just correct the count
* and exit.
*/
if (signal_pending(current)) {
retval = -EINTR;
sem->sleepers = 0;
atomic24_add(sleepers, &sem->count);
break;
}
/*
* Add "everybody else" into it. They aren't
* playing, because we own the spinlock. The
* "-1" is because we're still hoping to get
* the lock.
*/
if (!atomic24_add_negative(sleepers - 1, &sem->count)) {
sem->sleepers = 0;
break;
}
sem->sleepers = 1; /* us - see -1 above */
spin_unlock_irq(&semaphore_lock);
schedule();
tsk->state = TASK_INTERRUPTIBLE;
spin_lock_irq(&semaphore_lock);
}
spin_unlock_irq(&semaphore_lock);
tsk->state = TASK_RUNNING;
remove_wait_queue(&sem->wait, &wait);
wake_up(&sem->wait);
return retval;
}
/*
* Trylock failed - make sure we correct for
* having decremented the count.
*/
int __down_trylock(struct semaphore * sem)
{
int sleepers;
unsigned long flags;
spin_lock_irqsave(&semaphore_lock, flags);
sleepers = sem->sleepers + 1;
sem->sleepers = 0;
/*
* Add "everybody else" and us into it. They aren't
* playing, because we own the spinlock.
*/
if (!atomic24_add_negative(sleepers, &sem->count))
wake_up(&sem->wait);
spin_unlock_irqrestore(&semaphore_lock, flags);
return 1;
}
arch/sparc/kernel/sparc_ksyms.c
View file @ 64ac24e7
......@@ -107,11 +107,6 @@ EXPORT_SYMBOL(___rw_read_try);
EXPORT_SYMBOL(___rw_read_exit);
EXPORT_SYMBOL(___rw_write_enter);
#endif
/* semaphores */
EXPORT_SYMBOL(__up);
EXPORT_SYMBOL(__down);
EXPORT_SYMBOL(__down_trylock);
EXPORT_SYMBOL(__down_interruptible);
EXPORT_SYMBOL(sparc_valid_addr_bitmap);
EXPORT_SYMBOL(phys_base);
......
arch/sparc64/kernel/Makefile
View file @ 64ac24e7
......@@ -10,7 +10,7 @@ extra-y := head.o init_task.o vmlinux.lds
obj-y := process.o setup.o cpu.o idprom.o \
traps.o auxio.o una_asm.o sysfs.o iommu.o \
irq.o ptrace.o time.o sys_sparc.o signal.o \
unaligned.o central.o pci.o starfire.o semaphore.o \
unaligned.o central.o pci.o starfire.o \
power.o sbus.o sparc64_ksyms.o chmc.o \
visemul.o prom.o of_device.o hvapi.o sstate.o mdesc.o
......
arch/sparc64/kernel/semaphore.c deleted 100644 → 0
View file @ e48b3dee
/* semaphore.c: Sparc64 semaphore implementation.
*
* This is basically the PPC semaphore scheme ported to use
* the sparc64 atomic instructions, so see the PPC code for
* credits.
*/
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/init.h>
/*
* Atomically update sem->count.
* This does the equivalent of the following:
*
* old_count = sem->count;
* tmp = MAX(old_count, 0) + incr;
* sem->count = tmp;
* return old_count;
*/
static inline int __sem_update_count(struct semaphore *sem, int incr)
{
int old_count, tmp;
__asm__ __volatile__("\n"
" ! __sem_update_count old_count(%0) tmp(%1) incr(%4) &sem->count(%3)\n"
"1: ldsw [%3], %0\n"
" mov %0, %1\n"
" cmp %0, 0\n"
" movl %%icc, 0, %1\n"
" add %1, %4, %1\n"
" cas [%3], %0, %1\n"
" cmp %0, %1\n"
" membar #StoreLoad | #StoreStore\n"
" bne,pn %%icc, 1b\n"
" nop\n"
: "=&r" (old_count), "=&r" (tmp), "=m" (sem->count)
: "r" (&sem->count), "r" (incr), "m" (sem->count)
: "cc");
return old_count;
}
static void __up(struct semaphore *sem)
{
__sem_update_count(sem, 1);
wake_up(&sem->wait);
}
void up(struct semaphore *sem)
{
/* This atomically does:
* old_val = sem->count;
* new_val = sem->count + 1;
* sem->count = new_val;
* if (old_val < 0)
* __up(sem);
*
* The (old_val < 0) test is equivalent to
* the more straightforward (new_val <= 0),
* but it is easier to test the former because
* of how the CAS instruction works.
*/
__asm__ __volatile__("\n"
" ! up sem(%0)\n"
" membar #StoreLoad | #LoadLoad\n"
"1: lduw [%0], %%g1\n"
" add %%g1, 1, %%g7\n"
" cas [%0], %%g1, %%g7\n"
" cmp %%g1, %%g7\n"
" bne,pn %%icc, 1b\n"
" addcc %%g7, 1, %%g0\n"
" membar #StoreLoad | #StoreStore\n"
" ble,pn %%icc, 3f\n"
" nop\n"
"2:\n"
" .subsection 2\n"
"3: mov %0, %%g1\n"
" save %%sp, -160, %%sp\n"
" call %1\n"
" mov %%g1, %%o0\n"
" ba,pt %%xcc, 2b\n"
" restore\n"
" .previous\n"
: : "r" (sem), "i" (__up)
: "g1", "g2", "g3", "g7", "memory", "cc");
}
static void __sched __down(struct semaphore * sem)
{
struct task_struct *tsk = current;
DECLARE_WAITQUEUE(wait, tsk);
tsk->state = TASK_UNINTERRUPTIBLE;
add_wait_queue_exclusive(&sem->wait, &wait);
while (__sem_update_count(sem, -1) <= 0) {
schedule();
tsk->state = TASK_UNINTERRUPTIBLE;
}
remove_wait_queue(&sem->wait, &wait);
tsk->state = TASK_RUNNING;
wake_up(&sem->wait);
}
void __sched down(struct semaphore *sem)
{
might_sleep();
/* This atomically does:
* old_val = sem->count;
* new_val = sem->count - 1;
* sem->count = new_val;
* if (old_val < 1)
* __down(sem);
*
* The (old_val < 1) test is equivalent to
* the more straightforward (new_val < 0),
* but it is easier to test the former because
* of how the CAS instruction works.
*/
__asm__ __volatile__("\n"
" ! down sem(%0)\n"
"1: lduw [%0], %%g1\n"
" sub %%g1, 1, %%g7\n"
" cas [%0], %%g1, %%g7\n"
" cmp %%g1, %%g7\n"
" bne,pn %%icc, 1b\n"
" cmp %%g7, 1\n"
" membar #StoreLoad | #StoreStore\n"
" bl,pn %%icc, 3f\n"
" nop\n"
"2:\n"
" .subsection 2\n"
"3: mov %0, %%g1\n"
" save %%sp, -160, %%sp\n"
" call %1\n"
" mov %%g1, %%o0\n"
" ba,pt %%xcc, 2b\n"
" restore\n"
" .previous\n"
: : "r" (sem), "i" (__down)
: "g1", "g2", "g3", "g7", "memory", "cc");
}
int down_trylock(struct semaphore *sem)
{
int ret;
/* This atomically does:
* old_val = sem->count;
* new_val = sem->count - 1;
* if (old_val < 1) {
* ret = 1;
* } else {
* sem->count = new_val;
* ret = 0;
* }
*
* The (old_val < 1) test is equivalent to
* the more straightforward (new_val < 0),
* but it is easier to test the former because
* of how the CAS instruction works.
*/
__asm__ __volatile__("\n"
" ! down_trylock sem(%1) ret(%0)\n"
"1: lduw [%1], %%g1\n"
" sub %%g1, 1, %%g7\n"
" cmp %%g1, 1\n"
" bl,pn %%icc, 2f\n"
" mov 1, %0\n"
" cas [%1], %%g1, %%g7\n"
" cmp %%g1, %%g7\n"
" bne,pn %%icc, 1b\n"
" mov 0, %0\n"
" membar #StoreLoad | #StoreStore\n"
"2:\n"
: "=&r" (ret)
: "r" (sem)
: "g1", "g7", "memory", "cc");
return ret;
}
static int __sched __down_interruptible(struct semaphore * sem)
{
int retval = 0;
struct task_struct *tsk = current;
DECLARE_WAITQUEUE(wait, tsk);
tsk->state = TASK_INTERRUPTIBLE;
add_wait_queue_exclusive(&sem->wait, &wait);
while (__sem_update_count(sem, -1) <= 0) {
if (signal_pending(current)) {
__sem_update_count(sem, 0);
retval = -EINTR;
break;
}
schedule();
tsk->state = TASK_INTERRUPTIBLE;
}
tsk->state = TASK_RUNNING;
remove_wait_queue(&sem->wait, &wait);
wake_up(&sem->wait);
return retval;
}
int __sched down_interruptible(struct semaphore *sem)
{
int ret = 0;
might_sleep();
/* This atomically does:
* old_val = sem->count;
* new_val = sem->count - 1;
* sem->count = new_val;
* if (old_val < 1)
* ret = __down_interruptible(sem);
*
* The (old_val < 1) test is equivalent to
* the more straightforward (new_val < 0),
* but it is easier to test the former because
* of how the CAS instruction works.
*/
__asm__ __volatile__("\n"
" ! down_interruptible sem(%2) ret(%0)\n"
"1: lduw [%2], %%g1\n"
" sub %%g1, 1, %%g7\n"
" cas [%2], %%g1, %%g7\n"
" cmp %%g1, %%g7\n"
" bne,pn %%icc, 1b\n"
" cmp %%g7, 1\n"
" membar #StoreLoad | #StoreStore\n"
" bl,pn %%icc, 3f\n"
" nop\n"
"2:\n"
" .subsection 2\n"
"3: mov %2, %%g1\n"
" save %%sp, -160, %%sp\n"
" call %3\n"
" mov %%g1, %%o0\n"
" ba,pt %%xcc, 2b\n"
" restore\n"
" .previous\n"
: "=r" (ret)
: "0" (ret), "r" (sem), "i" (__down_interruptible)
: "g1", "g2", "g3", "g7", "memory", "cc");
return ret;
}
arch/sparc64/kernel/sparc64_ksyms.c
View file @ 64ac24e7
......@@ -130,12 +130,6 @@ EXPORT_SYMBOL(_mcount);
EXPORT_SYMBOL(sparc64_get_clock_tick);
/* semaphores */
EXPORT_SYMBOL(down);
EXPORT_SYMBOL(down_trylock);
EXPORT_SYMBOL(down_interruptible);
EXPORT_SYMBOL(up);
/* RW semaphores */
EXPORT_SYMBOL(__down_read);
EXPORT_SYMBOL(__down_read_trylock);
......
arch/um/Kconfig.i386
View file @ 64ac24e7
......@@ -19,10 +19,6 @@ config 64BIT
bool
default n
config SEMAPHORE_SLEEPERS
bool
default y
config 3_LEVEL_PGTABLES
bool "Three-level pagetables (EXPERIMENTAL)"
default n
......
arch/um/Kconfig.x86_64
View file @ 64ac24e7
......@@ -11,10 +11,6 @@ config RWSEM_GENERIC_SPINLOCK
bool
default y
config SEMAPHORE_SLEEPERS
bool
default y
config 3_LEVEL_PGTABLES
bool
default y
......
arch/um/sys-i386/ksyms.c
View file @ 64ac24e7
#include "linux/module.h"
#include "linux/in6.h"
#include "linux/rwsem.h"
#include "asm/byteorder.h"
#include "asm/delay.h"
#include "asm/semaphore.h"
#include "asm/uaccess.h"
#include "asm/checksum.h"
#include "asm/errno.h"
EXPORT_SYMBOL(__down_failed);
EXPORT_SYMBOL(__down_failed_interruptible);
EXPORT_SYMBOL(__down_failed_trylock);
EXPORT_SYMBOL(__up_wakeup);
/* Networking helper routines. */
EXPORT_SYMBOL(csum_partial);
arch/um/sys-ppc/Makefile
View file @ 64ac24e7
......@@ -3,7 +3,7 @@ OBJ = built-in.o
.S.o:
$(CC) $(KBUILD_AFLAGS) -D__ASSEMBLY__ -D__UM_PPC__ -c $< -o $*.o
OBJS = ptrace.o sigcontext.o semaphore.o checksum.o miscthings.o misc.o \
OBJS = ptrace.o sigcontext.o checksum.o miscthings.o misc.o \
ptrace_user.o sysrq.o
EXTRA_AFLAGS := -DCONFIG_PPC32 -I. -I$(srctree)/arch/ppc/kernel
......@@ -20,10 +20,6 @@ ptrace_user.o: ptrace_user.c
sigcontext.o: sigcontext.c
$(CC) $(USER_CFLAGS) $(EXTRA_CFLAGS) -c -o $@ $<
semaphore.c:
rm -f $@
ln -s $(srctree)/arch/ppc/kernel/$@ $@
checksum.S:
rm -f $@
ln -s $(srctree)/arch/ppc/lib/$@ $@
......@@ -66,4 +62,4 @@ misc.o: misc.S ppc_defs.h
$(CC) $(EXTRA_AFLAGS) $(KBUILD_AFLAGS) -D__ASSEMBLY__ -D__UM_PPC__ -c $< -o $*.o
rm -f asm
clean-files := $(OBJS) ppc_defs.h checksum.S semaphore.c mk_defs.c
clean-files := $(OBJS) ppc_defs.h checksum.S mk_defs.c
arch/um/sys-x86_64/ksyms.c
View file @ 64ac24e7
#include "linux/module.h"
#include "linux/in6.h"
#include "linux/rwsem.h"
#include "asm/byteorder.h"
#include "asm/semaphore.h"
#include "asm/uaccess.h"
#include "asm/checksum.h"
#include "asm/errno.h"
EXPORT_SYMBOL(__down_failed);
EXPORT_SYMBOL(__down_failed_interruptible);
EXPORT_SYMBOL(__down_failed_trylock);
EXPORT_SYMBOL(__up_wakeup);
#include "asm/string.h"
/*XXX: we need them because they would be exported by x86_64 */
EXPORT_SYMBOL(__memcpy);
arch/v850/kernel/Makefile
View file @ 64ac24e7
......@@ -11,7 +11,7 @@
extra-y := head.o init_task.o vmlinux.lds
obj-y += intv.o entry.o process.o syscalls.o time.o semaphore.o setup.o \
obj-y += intv.o entry.o process.o syscalls.o time.o setup.o \
signal.o irq.o mach.o ptrace.o bug.o
obj-$(CONFIG_MODULES) += module.o v850_ksyms.o
# chip-specific code
......
arch/v850/kernel/semaphore.c deleted 100644 → 0
View file @ e48b3dee
/*
* arch/v850/kernel/semaphore.c -- Semaphore support
*
* Copyright (C) 1998-2000 IBM Corporation
* Copyright (C) 1999 Linus Torvalds
*
* This file is subject to the terms and conditions of the GNU General
* Public License. See the file COPYING in the main directory of this
* archive for more details.
*
* This file is a copy of the s390 version, arch/s390/kernel/semaphore.c
* Author(s): Martin Schwidefsky
* which was derived from the i386 version, linux/arch/i386/kernel/semaphore.c
*/
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/init.h>
#include <asm/semaphore.h>
/*
* Semaphores are implemented using a two-way counter:
* The "count" variable is decremented for each process
* that tries to acquire the semaphore, while the "sleeping"
* variable is a count of such acquires.
*
* Notably, the inline "up()" and "down()" functions can
* efficiently test if they need to do any extra work (up
* needs to do something only if count was negative before
* the increment operation.
*
* "sleeping" and the contention routine ordering is
* protected by the semaphore spinlock.
*
* Note that these functions are only called when there is
* contention on the lock, and as such all this is the
* "non-critical" part of the whole semaphore business. The
* critical part is the inline stuff in <asm/semaphore.h>
* where we want to avoid any extra jumps and calls.
*/
/*
* Logic:
* - only on a boundary condition do we need to care. When we go
* from a negative count to a non-negative, we wake people up.
* - when we go from a non-negative count to a negative do we
* (a) synchronize with the "sleeper" count and (b) make sure
* that we're on the wakeup list before we synchronize so that
* we cannot lose wakeup events.
*/
void __up(struct semaphore *sem)
{
wake_up(&sem->wait);
}
static DEFINE_SPINLOCK(semaphore_lock);
void __sched __down(struct semaphore * sem)
{
struct task_struct *tsk = current;
DECLARE_WAITQUEUE(wait, tsk);
tsk->state = TASK_UNINTERRUPTIBLE;
add_wait_queue_exclusive(&sem->wait, &wait);
spin_lock_irq(&semaphore_lock);
sem->sleepers++;
for (;;) {
int sleepers = sem->sleepers;
/*
* Add "everybody else" into it. They aren't
* playing, because we own the spinlock.
*/
if (!atomic_add_negative(sleepers - 1, &sem->count)) {
sem->sleepers = 0;
break;
}
sem->sleepers = 1; /* us - see -1 above */
spin_unlock_irq(&semaphore_lock);
schedule();
tsk->state = TASK_UNINTERRUPTIBLE;
spin_lock_irq(&semaphore_lock);
}
spin_unlock_irq(&semaphore_lock);
remove_wait_queue(&sem->wait, &wait);
tsk->state = TASK_RUNNING;
wake_up(&sem->wait);
}
int __sched __down_interruptible(struct semaphore * sem)
{
int retval = 0;
struct task_struct *tsk = current;
DECLARE_WAITQUEUE(wait, tsk);
tsk->state = TASK_INTERRUPTIBLE;
add_wait_queue_exclusive(&sem->wait, &wait);
spin_lock_irq(&semaphore_lock);
sem->sleepers ++;
for (;;) {
int sleepers = sem->sleepers;
/*
* With signals pending, this turns into
* the trylock failure case - we won't be
* sleeping, and we* can't get the lock as
* it has contention. Just correct the count
* and exit.
*/
if (signal_pending(current)) {
retval = -EINTR;
sem->sleepers = 0;
atomic_add(sleepers, &sem->count);
break;
}
/*
* Add "everybody else" into it. They aren't
* playing, because we own the spinlock. The
* "-1" is because we're still hoping to get
* the lock.
*/
if (!atomic_add_negative(sleepers - 1, &sem->count)) {
sem->sleepers = 0;
break;
}
sem->sleepers = 1; /* us - see -1 above */
spin_unlock_irq(&semaphore_lock);
schedule();
tsk->state = TASK_INTERRUPTIBLE;
spin_lock_irq(&semaphore_lock);
}
spin_unlock_irq(&semaphore_lock);
tsk->state = TASK_RUNNING;
remove_wait_queue(&sem->wait, &wait);
wake_up(&sem->wait);
return retval;
}
/*
* Trylock failed - make sure we correct for
* having decremented the count.
*/
int __down_trylock(struct semaphore * sem)
{
unsigned long flags;
int sleepers;
spin_lock_irqsave(&semaphore_lock, flags);
sleepers = sem->sleepers + 1;
sem->sleepers = 0;
/*
* Add "everybody else" and us into it. They aren't
* playing, because we own the spinlock.
*/
if (!atomic_add_negative(sleepers, &sem->count))
wake_up(&sem->wait);
spin_unlock_irqrestore(&semaphore_lock, flags);
return 1;
}
arch/v850/kernel/v850_ksyms.c
View file @ 64ac24e7
......@@ -11,7 +11,6 @@
#include <asm/pgalloc.h>
#include <asm/irq.h>
#include <asm/io.h>
#include <asm/semaphore.h>
#include <asm/checksum.h>
#include <asm/current.h>
......@@ -34,12 +33,6 @@ EXPORT_SYMBOL (memset);
EXPORT_SYMBOL (memcpy);
EXPORT_SYMBOL (memmove);
/* semaphores */
EXPORT_SYMBOL (__down);
EXPORT_SYMBOL (__down_interruptible);
EXPORT_SYMBOL (__down_trylock);
EXPORT_SYMBOL (__up);
/*
* libgcc functions - functions that are used internally by the
* compiler... (prototypes are not correct though, but that
......
arch/x86/Kconfig
View file @ 64ac24e7
......@@ -53,9 +53,6 @@ config STACKTRACE_SUPPORT
config HAVE_LATENCYTOP_SUPPORT
def_bool y
config SEMAPHORE_SLEEPERS
def_bool y
config FAST_CMPXCHG_LOCAL
bool
default y
......
arch/x86/kernel/i386_ksyms_32.c
View file @ 64ac24e7
#include <linux/module.h>
#include <asm/semaphore.h>
#include <asm/checksum.h>
#include <asm/desc.h>
#include <asm/pgtable.h>
EXPORT_SYMBOL(__down_failed);
EXPORT_SYMBOL(__down_failed_interruptible);
EXPORT_SYMBOL(__down_failed_trylock);
EXPORT_SYMBOL(__up_wakeup);
/* Networking helper routines. */
EXPORT_SYMBOL(csum_partial_copy_generic);
......
arch/x86/kernel/x8664_ksyms_64.c
View file @ 64ac24e7
......@@ -4,7 +4,6 @@
#include <linux/module.h>
#include <linux/smp.h>
#include <asm/semaphore.h>
#include <asm/processor.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
......@@ -12,11 +11,6 @@
EXPORT_SYMBOL(kernel_thread);
EXPORT_SYMBOL(__down_failed);
EXPORT_SYMBOL(__down_failed_interruptible);
EXPORT_SYMBOL(__down_failed_trylock);
EXPORT_SYMBOL(__up_wakeup);
EXPORT_SYMBOL(__get_user_1);
EXPORT_SYMBOL(__get_user_2);
EXPORT_SYMBOL(__get_user_4);
......
arch/x86/lib/semaphore_32.S
View file @ 64ac24e7
......@@ -30,89 +30,6 @@
* value or just clobbered..
*/
.section .sched.text, "ax"
ENTRY(__down_failed)
CFI_STARTPROC
FRAME
pushl %edx
CFI_ADJUST_CFA_OFFSET 4
CFI_REL_OFFSET edx,0
pushl %ecx
CFI_ADJUST_CFA_OFFSET 4
CFI_REL_OFFSET ecx,0
call __down
popl %ecx
CFI_ADJUST_CFA_OFFSET -4
CFI_RESTORE ecx
popl %edx
CFI_ADJUST_CFA_OFFSET -4
CFI_RESTORE edx
ENDFRAME
ret
CFI_ENDPROC
ENDPROC(__down_failed)
ENTRY(__down_failed_interruptible)
CFI_STARTPROC
FRAME
pushl %edx
CFI_ADJUST_CFA_OFFSET 4
CFI_REL_OFFSET edx,0
pushl %ecx
CFI_ADJUST_CFA_OFFSET 4
CFI_REL_OFFSET ecx,0
call __down_interruptible
popl %ecx
CFI_ADJUST_CFA_OFFSET -4
CFI_RESTORE ecx
popl %edx
CFI_ADJUST_CFA_OFFSET -4
CFI_RESTORE edx
ENDFRAME
ret
CFI_ENDPROC
ENDPROC(__down_failed_interruptible)
ENTRY(__down_failed_trylock)
CFI_STARTPROC
FRAME
pushl %edx
CFI_ADJUST_CFA_OFFSET 4
CFI_REL_OFFSET edx,0
pushl %ecx
CFI_ADJUST_CFA_OFFSET 4
CFI_REL_OFFSET ecx,0
call __down_trylock
popl %ecx
CFI_ADJUST_CFA_OFFSET -4
CFI_RESTORE ecx
popl %edx
CFI_ADJUST_CFA_OFFSET -4
CFI_RESTORE edx
ENDFRAME
ret
CFI_ENDPROC
ENDPROC(__down_failed_trylock)
ENTRY(__up_wakeup)
CFI_STARTPROC
FRAME
pushl %edx
CFI_ADJUST_CFA_OFFSET 4
CFI_REL_OFFSET edx,0
pushl %ecx
CFI_ADJUST_CFA_OFFSET 4
CFI_REL_OFFSET ecx,0
call __up
popl %ecx
CFI_ADJUST_CFA_OFFSET -4
CFI_RESTORE ecx
popl %edx
CFI_ADJUST_CFA_OFFSET -4
CFI_RESTORE edx
ENDFRAME
ret
CFI_ENDPROC
ENDPROC(__up_wakeup)
/*
* rw spinlock fallbacks
......
arch/x86/lib/thunk_64.S
View file @ 64ac24e7
......@@ -41,11 +41,6 @@
thunk rwsem_downgrade_thunk,rwsem_downgrade_wake
#endif
thunk __down_failed,__down
thunk_retrax __down_failed_interruptible,__down_interruptible
thunk_retrax __down_failed_trylock,__down_trylock
thunk __up_wakeup,__up
#ifdef CONFIG_TRACE_IRQFLAGS
thunk trace_hardirqs_on_thunk,trace_hardirqs_on
thunk trace_hardirqs_off_thunk,trace_hardirqs_off
......
arch/xtensa/kernel/Makefile
View file @ 64ac24e7
......@@ -5,7 +5,7 @@
extra-y := head.o vmlinux.lds
obj-y := align.o entry.o irq.o coprocessor.o process.o ptrace.o semaphore.o \
obj-y := align.o entry.o irq.o coprocessor.o process.o ptrace.o \
setup.o signal.o syscall.o time.o traps.o vectors.o platform.o \
pci-dma.o init_task.o io.o
......
arch/xtensa/kernel/semaphore.c deleted 100644 → 0
View file @ e48b3dee
/*
* arch/xtensa/kernel/semaphore.c
*
* Generic semaphore code. Buyer beware. Do your own specific changes
* in <asm/semaphore-helper.h>
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 2001 - 2005 Tensilica Inc.
*
* Joe Taylor <joe@tensilica.com, joetylr@yahoo.com>
* Chris Zankel <chris@zankel.net>
* Marc Gauthier<marc@tensilica.com, marc@alumni.uwaterloo.ca>
* Kevin Chea
*/
#include <linux/sched.h>
#include <linux/wait.h>
#include <linux/init.h>
#include <asm/semaphore.h>
#include <asm/errno.h>
/*
* These two _must_ execute atomically wrt each other.
*/
static __inline__ void wake_one_more(struct semaphore * sem)
{
atomic_inc((atomic_t *)&sem->sleepers);
}
static __inline__ int waking_non_zero(struct semaphore *sem)
{
unsigned long flags;
int ret = 0;
spin_lock_irqsave(&semaphore_wake_lock, flags);
if (sem->sleepers > 0) {
sem->sleepers--;
ret = 1;
}
spin_unlock_irqrestore(&semaphore_wake_lock, flags);
return ret;
}
/*
* waking_non_zero_interruptible:
* 1 got the lock
* 0 go to sleep
* -EINTR interrupted
*
* We must undo the sem->count down_interruptible() increment while we are
* protected by the spinlock in order to make atomic this atomic_inc() with the
* atomic_read() in wake_one_more(), otherwise we can race. -arca
*/
static __inline__ int waking_non_zero_interruptible(struct semaphore *sem,
struct task_struct *tsk)
{
unsigned long flags;
int ret = 0;
spin_lock_irqsave(&semaphore_wake_lock, flags);
if (sem->sleepers > 0) {
sem->sleepers--;
ret = 1;
} else if (signal_pending(tsk)) {
atomic_inc(&sem->count);
ret = -EINTR;
}
spin_unlock_irqrestore(&semaphore_wake_lock, flags);
return ret;
}
/*
* waking_non_zero_trylock:
* 1 failed to lock
* 0 got the lock
*
* We must undo the sem->count down_trylock() increment while we are
* protected by the spinlock in order to make atomic this atomic_inc() with the
* atomic_read() in wake_one_more(), otherwise we can race. -arca
*/
static __inline__ int waking_non_zero_trylock(struct semaphore *sem)
{
unsigned long flags;
int ret = 1;
spin_lock_irqsave(&semaphore_wake_lock, flags);
if (sem->sleepers <= 0)
atomic_inc(&sem->count);
else {
sem->sleepers--;
ret = 0;
}
spin_unlock_irqrestore(&semaphore_wake_lock, flags);
return ret;
}
DEFINE_SPINLOCK(semaphore_wake_lock);
/*
* Semaphores are implemented using a two-way counter:
* The "count" variable is decremented for each process
* that tries to sleep, while the "waking" variable is
* incremented when the "up()" code goes to wake up waiting
* processes.
*
* Notably, the inline "up()" and "down()" functions can
* efficiently test if they need to do any extra work (up
* needs to do something only if count was negative before
* the increment operation.
*
* waking_non_zero() (from asm/semaphore.h) must execute
* atomically.
*
* When __up() is called, the count was negative before
* incrementing it, and we need to wake up somebody.
*
* This routine adds one to the count of processes that need to
* wake up and exit. ALL waiting processes actually wake up but
* only the one that gets to the "waking" field first will gate
* through and acquire the semaphore. The others will go back
* to sleep.
*
* Note that these functions are only called when there is
* contention on the lock, and as such all this is the
* "non-critical" part of the whole semaphore business. The
* critical part is the inline stuff in <asm/semaphore.h>
* where we want to avoid any extra jumps and calls.
*/
void __up(struct semaphore *sem)
{
wake_one_more(sem);
wake_up(&sem->wait);
}
/*
* Perform the "down" function. Return zero for semaphore acquired,
* return negative for signalled out of the function.
*
* If called from __down, the return is ignored and the wait loop is
* not interruptible. This means that a task waiting on a semaphore
* using "down()" cannot be killed until someone does an "up()" on
* the semaphore.
*
* If called from __down_interruptible, the return value gets checked
* upon return. If the return value is negative then the task continues
* with the negative value in the return register (it can be tested by
* the caller).
*
* Either form may be used in conjunction with "up()".
*
*/
#define DOWN_VAR \
struct task_struct *tsk = current; \
wait_queue_t wait; \
init_waitqueue_entry(&wait, tsk);
#define DOWN_HEAD(task_state) \
\
\
tsk->state = (task_state); \
add_wait_queue(&sem->wait, &wait); \
\
/* \
* Ok, we're set up. sem->count is known to be less than zero \
* so we must wait. \
* \
* We can let go the lock for purposes of waiting. \
* We re-acquire it after awaking so as to protect \
* all semaphore operations. \
* \
* If "up()" is called before we call waking_non_zero() then \
* we will catch it right away. If it is called later then \
* we will have to go through a wakeup cycle to catch it. \
* \
* Multiple waiters contend for the semaphore lock to see \
* who gets to gate through and who has to wait some more. \
*/ \
for (;;) {
#define DOWN_TAIL(task_state) \
tsk->state = (task_state); \
} \
tsk->state = TASK_RUNNING; \
remove_wait_queue(&sem->wait, &wait);
void __sched __down(struct semaphore * sem)
{
DOWN_VAR
DOWN_HEAD(TASK_UNINTERRUPTIBLE)
if (waking_non_zero(sem))
break;
schedule();
DOWN_TAIL(TASK_UNINTERRUPTIBLE)
}
int __sched __down_interruptible(struct semaphore * sem)
{
int ret = 0;
DOWN_VAR
DOWN_HEAD(TASK_INTERRUPTIBLE)
ret = waking_non_zero_interruptible(sem, tsk);
if (ret)
{
if (ret == 1)
/* ret != 0 only if we get interrupted -arca */
ret = 0;
break;
}
schedule();
DOWN_TAIL(TASK_INTERRUPTIBLE)
return ret;
}
int __down_trylock(struct semaphore * sem)
{
return waking_non_zero_trylock(sem);
}
arch/xtensa/kernel/xtensa_ksyms.c
View file @ 64ac24e7
......@@ -26,7 +26,6 @@
#include <asm/io.h>
#include <asm/page.h>
#include <asm/pgalloc.h>
#include <asm/semaphore.h>
#ifdef CONFIG_BLK_DEV_FD
#include <asm/floppy.h>
#endif
......@@ -71,14 +70,6 @@ EXPORT_SYMBOL(__umodsi3);
EXPORT_SYMBOL(__udivdi3);
EXPORT_SYMBOL(__umoddi3);
/*
* Semaphore operations
*/
EXPORT_SYMBOL(__down);
EXPORT_SYMBOL(__down_interruptible);
EXPORT_SYMBOL(__down_trylock);
EXPORT_SYMBOL(__up);
#ifdef CONFIG_NET
/*
* Networking support
......
include/asm-alpha/semaphore.h
View file @ 64ac24e7
#ifndef _ALPHA_SEMAPHORE_H
#define _ALPHA_SEMAPHORE_H
/*
* SMP- and interrupt-safe semaphores..
*
* (C) Copyright 1996 Linus Torvalds
* (C) Copyright 1996, 2000 Richard Henderson
*/
#include <asm/current.h>
#include <asm/system.h>
#include <asm/atomic.h>
#include <linux/compiler.h>
#include <linux/wait.h>
#include <linux/rwsem.h>
struct semaphore {
atomic_t count;
wait_queue_head_t wait;
};
#define __SEMAPHORE_INITIALIZER(name, n) \
{ \
.count = ATOMIC_INIT(n), \
.wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait), \
}
#define __DECLARE_SEMAPHORE_GENERIC(name,count) \
struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
static inline void sema_init(struct semaphore *sem, int val)
{
/*
* Logically,
* *sem = (struct semaphore)__SEMAPHORE_INITIALIZER((*sem),val);
* except that gcc produces better initializing by parts yet.
*/
atomic_set(&sem->count, val);
init_waitqueue_head(&sem->wait);
}
static inline void init_MUTEX (struct semaphore *sem)
{
sema_init(sem, 1);
}
static inline void init_MUTEX_LOCKED (struct semaphore *sem)
{
sema_init(sem, 0);
}
extern void down(struct semaphore *);
extern void __down_failed(struct semaphore *);
extern int down_interruptible(struct semaphore *);
extern int __down_failed_interruptible(struct semaphore *);
extern int down_trylock(struct semaphore *);
extern void up(struct semaphore *);
extern void __up_wakeup(struct semaphore *);
/*
* Hidden out of line code is fun, but extremely messy. Rely on newer
* compilers to do a respectable job with this. The contention cases
* are handled out of line in arch/alpha/kernel/semaphore.c.
*/
static inline void __down(struct semaphore *sem)
{
long count;
might_sleep();
count = atomic_dec_return(&sem->count);
if (unlikely(count < 0))
__down_failed(sem);
}
static inline int __down_interruptible(struct semaphore *sem)
{
long count;
might_sleep();
count = atomic_dec_return(&sem->count);
if (unlikely(count < 0))
return __down_failed_interruptible(sem);
return 0;
}
/*
* down_trylock returns 0 on success, 1 if we failed to get the lock.
*/
static inline int __down_trylock(struct semaphore *sem)
{
long ret;
/* "Equivalent" C:
do {
ret = ldl_l;
--ret;
if (ret < 0)
break;
ret = stl_c = ret;
} while (ret == 0);
*/
__asm__ __volatile__(
"1: ldl_l %0,%1\n"
" subl %0,1,%0\n"
" blt %0,2f\n"
" stl_c %0,%1\n"
" beq %0,3f\n"
" mb\n"
"2:\n"
".subsection 2\n"
"3: br 1b\n"
".previous"
: "=&r" (ret), "=m" (sem->count)
: "m" (sem->count));
return ret < 0;
}
static inline void __up(struct semaphore *sem)
{
if (unlikely(atomic_inc_return(&sem->count) <= 0))
__up_wakeup(sem);
}
#if !defined(CONFIG_DEBUG_SEMAPHORE)
extern inline void down(struct semaphore *sem)
{
__down(sem);
}
extern inline int down_interruptible(struct semaphore *sem)
{
return __down_interruptible(sem);
}
extern inline int down_trylock(struct semaphore *sem)
{
return __down_trylock(sem);
}
extern inline void up(struct semaphore *sem)
{
__up(sem);
}
#endif
#endif
#include <linux/semaphore.h>
include/asm-arm/semaphore-helper.h deleted 100644 → 0
View file @ e48b3dee
#ifndef ASMARM_SEMAPHORE_HELPER_H
#define ASMARM_SEMAPHORE_HELPER_H
/*
* These two _must_ execute atomically wrt each other.
*/
static inline void wake_one_more(struct semaphore * sem)
{
unsigned long flags;
spin_lock_irqsave(&semaphore_wake_lock, flags);
if (atomic_read(&sem->count) <= 0)
sem->waking++;
spin_unlock_irqrestore(&semaphore_wake_lock, flags);
}
static inline int waking_non_zero(struct semaphore *sem)
{
unsigned long flags;
int ret = 0;
spin_lock_irqsave(&semaphore_wake_lock, flags);
if (sem->waking > 0) {
sem->waking--;
ret = 1;
}
spin_unlock_irqrestore(&semaphore_wake_lock, flags);
return ret;
}
/*
* waking non zero interruptible
* 1 got the lock
* 0 go to sleep
* -EINTR interrupted
*
* We must undo the sem->count down_interruptible() increment while we are
* protected by the spinlock in order to make this atomic_inc() with the
* atomic_read() in wake_one_more(), otherwise we can race. -arca
*/
static inline int waking_non_zero_interruptible(struct semaphore *sem,
struct task_struct *tsk)
{
unsigned long flags;
int ret = 0;
spin_lock_irqsave(&semaphore_wake_lock, flags);
if (sem->waking > 0) {
sem->waking--;
ret = 1;
} else if (signal_pending(tsk)) {
atomic_inc(&sem->count);
ret = -EINTR;
}
spin_unlock_irqrestore(&semaphore_wake_lock, flags);
return ret;
}
/*
* waking_non_zero_try_lock:
* 1 failed to lock
* 0 got the lock
*
* We must undo the sem->count down_interruptible() increment while we are
* protected by the spinlock in order to make this atomic_inc() with the
* atomic_read() in wake_one_more(), otherwise we can race. -arca
*/
static inline int waking_non_zero_trylock(struct semaphore *sem)
{
unsigned long flags;
int ret = 1;
spin_lock_irqsave(&semaphore_wake_lock, flags);
if (sem->waking <= 0)
atomic_inc(&sem->count);
else {
sem->waking--;
ret = 0;
}
spin_unlock_irqrestore(&semaphore_wake_lock, flags);
return ret;
}
#endif
include/asm-arm/semaphore.h
View file @ 64ac24e7
/*
* linux/include/asm-arm/semaphore.h
*/
#ifndef __ASM_ARM_SEMAPHORE_H
#define __ASM_ARM_SEMAPHORE_H
#include <linux/linkage.h>
#include <linux/spinlock.h>
#include <linux/wait.h>
#include <linux/rwsem.h>
#include <asm/atomic.h>
#include <asm/locks.h>
struct semaphore {
atomic_t count;
int sleepers;
wait_queue_head_t wait;
};
#define __SEMAPHORE_INIT(name, cnt) \
{ \
.count = ATOMIC_INIT(cnt), \
.wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait), \
}
#define __DECLARE_SEMAPHORE_GENERIC(name,count) \
struct semaphore name = __SEMAPHORE_INIT(name,count)
#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
static inline void sema_init(struct semaphore *sem, int val)
{
atomic_set(&sem->count, val);
sem->sleepers = 0;
init_waitqueue_head(&sem->wait);
}
static inline void init_MUTEX(struct semaphore *sem)
{
sema_init(sem, 1);
}
static inline void init_MUTEX_LOCKED(struct semaphore *sem)
{
sema_init(sem, 0);
}
/*
* special register calling convention
*/
asmlinkage void __down_failed(void);
asmlinkage int __down_interruptible_failed(void);
asmlinkage int __down_trylock_failed(void);
asmlinkage void __up_wakeup(void);
extern void __down(struct semaphore * sem);
extern int __down_interruptible(struct semaphore * sem);
extern int __down_trylock(struct semaphore * sem);
extern void __up(struct semaphore * sem);
/*
* This is ugly, but we want the default case to fall through.
* "__down" is the actual routine that waits...
*/
static inline void down(struct semaphore * sem)
{
might_sleep();
__down_op(sem, __down_failed);
}
/*
* This is ugly, but we want the default case to fall through.
* "__down_interruptible" is the actual routine that waits...
*/
static inline int down_interruptible (struct semaphore * sem)
{
might_sleep();
return __down_op_ret(sem, __down_interruptible_failed);
}
static inline int down_trylock(struct semaphore *sem)
{
return __down_op_ret(sem, __down_trylock_failed);
}
/*
* Note! This is subtle. We jump to wake people up only if
* the semaphore was negative (== somebody was waiting on it).
* The default case (no contention) will result in NO
* jumps for both down() and up().
*/
static inline void up(struct semaphore * sem)
{
__up_op(sem, __up_wakeup);
}
#endif
#include <linux/semaphore.h>
include/asm-avr32/semaphore.h
View file @ 64ac24e7
/*
* SMP- and interrupt-safe semaphores.
*
* Copyright (C) 2006 Atmel Corporation
*
* Based on include/asm-i386/semaphore.h
* Copyright (C) 1996 Linus Torvalds
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#ifndef __ASM_AVR32_SEMAPHORE_H
#define __ASM_AVR32_SEMAPHORE_H
#include <linux/linkage.h>
#include <asm/system.h>
#include <asm/atomic.h>
#include <linux/wait.h>
#include <linux/rwsem.h>
struct semaphore {
atomic_t count;
int sleepers;
wait_queue_head_t wait;
};
#define __SEMAPHORE_INITIALIZER(name, n) \
{ \
.count = ATOMIC_INIT(n), \
.wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \
}
#define __DECLARE_SEMAPHORE_GENERIC(name,count) \
struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
static inline void sema_init (struct semaphore *sem, int val)
{
atomic_set(&sem->count, val);
sem->sleepers = 0;
init_waitqueue_head(&sem->wait);
}
static inline void init_MUTEX (struct semaphore *sem)
{
sema_init(sem, 1);
}
static inline void init_MUTEX_LOCKED (struct semaphore *sem)
{
sema_init(sem, 0);
}
void __down(struct semaphore * sem);
int __down_interruptible(struct semaphore * sem);
void __up(struct semaphore * sem);
/*
* This is ugly, but we want the default case to fall through.
* "__down_failed" is a special asm handler that calls the C
* routine that actually waits. See arch/i386/kernel/semaphore.c
*/
static inline void down(struct semaphore * sem)
{
might_sleep();
if (unlikely(atomic_dec_return (&sem->count) < 0))
__down (sem);
}
/*
* Interruptible try to acquire a semaphore. If we obtained
* it, return zero. If we were interrupted, returns -EINTR
*/
static inline int down_interruptible(struct semaphore * sem)
{
int ret = 0;
might_sleep();
if (unlikely(atomic_dec_return (&sem->count) < 0))
ret = __down_interruptible (sem);
return ret;
}
/*
* Non-blockingly attempt to down() a semaphore.
* Returns zero if we acquired it
*/
static inline int down_trylock(struct semaphore * sem)
{
return atomic_dec_if_positive(&sem->count) < 0;
}
/*
* Note! This is subtle. We jump to wake people up only if
* the semaphore was negative (== somebody was waiting on it).
* The default case (no contention) will result in NO
* jumps for both down() and up().
*/
static inline void up(struct semaphore * sem)
{
if (unlikely(atomic_inc_return (&sem->count) <= 0))
__up (sem);
}
#endif /*__ASM_AVR32_SEMAPHORE_H */
#include <linux/semaphore.h>
include/asm-blackfin/semaphore-helper.h deleted 100644 → 0
View file @ e48b3dee
/* Based on M68K version, Lineo Inc. May 2001 */
#ifndef _BFIN_SEMAPHORE_HELPER_H
#define _BFIN_SEMAPHORE_HELPER_H
/*
* SMP- and interrupt-safe semaphores helper functions.
*
* (C) Copyright 1996 Linus Torvalds
*
*/
#include <asm/errno.h>
/*
* These two _must_ execute atomically wrt each other.
*/
static inline void wake_one_more(struct semaphore *sem)
{
atomic_inc(&sem->waking);
}
static inline int waking_non_zero(struct semaphore *sem)
{
int ret;
unsigned long flags = 0;
spin_lock_irqsave(&semaphore_wake_lock, flags);
ret = 0;
if (atomic_read(&sem->waking) > 0) {
atomic_dec(&sem->waking);
ret = 1;
}
spin_unlock_irqrestore(&semaphore_wake_lock, flags);
return ret;
}
/*
* waking_non_zero_interruptible:
* 1 got the lock
* 0 go to sleep
* -EINTR interrupted
*/
static inline int waking_non_zero_interruptible(struct semaphore *sem,
struct task_struct *tsk)
{
int ret = 0;
unsigned long flags = 0;
spin_lock_irqsave(&semaphore_wake_lock, flags);
if (atomic_read(&sem->waking) > 0) {
atomic_dec(&sem->waking);
ret = 1;
} else if (signal_pending(tsk)) {
atomic_inc(&sem->count);
ret = -EINTR;
}
spin_unlock_irqrestore(&semaphore_wake_lock, flags);
return ret;
}
/*
* waking_non_zero_trylock:
* 1 failed to lock
* 0 got the lock
*/
static inline int waking_non_zero_trylock(struct semaphore *sem)
{
int ret = 1;
unsigned long flags = 0;
spin_lock_irqsave(&semaphore_wake_lock, flags);
if (atomic_read(&sem->waking) > 0) {
atomic_dec(&sem->waking);
ret = 0;
} else
atomic_inc(&sem->count);
spin_unlock_irqrestore(&semaphore_wake_lock, flags);
return ret;
}
#endif /* _BFIN_SEMAPHORE_HELPER_H */
include/asm-blackfin/semaphore.h
View file @ 64ac24e7
#ifndef _BFIN_SEMAPHORE_H
#define _BFIN_SEMAPHORE_H
#ifndef __ASSEMBLY__
#include <linux/linkage.h>
#include <linux/wait.h>
#include <linux/spinlock.h>
#include <linux/rwsem.h>
#include <asm/atomic.h>
/*
* Interrupt-safe semaphores..
*
* (C) Copyright 1996 Linus Torvalds
*
* BFIN version by akbar hussain Lineo Inc April 2001
*
*/
struct semaphore {
atomic_t count;
int sleepers;
wait_queue_head_t wait;
};
#define __SEMAPHORE_INITIALIZER(name, n) \
{ \
.count = ATOMIC_INIT(n), \
.sleepers = 0, \
.wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \
}
#define __DECLARE_SEMAPHORE_GENERIC(name,count) \
struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
static inline void sema_init(struct semaphore *sem, int val)
{
*sem = (struct semaphore)__SEMAPHORE_INITIALIZER(*sem, val);
}
static inline void init_MUTEX(struct semaphore *sem)
{
sema_init(sem, 1);
}
static inline void init_MUTEX_LOCKED(struct semaphore *sem)
{
sema_init(sem, 0);
}
asmlinkage void __down(struct semaphore *sem);
asmlinkage int __down_interruptible(struct semaphore *sem);
asmlinkage int __down_trylock(struct semaphore *sem);
asmlinkage void __up(struct semaphore *sem);
extern spinlock_t semaphore_wake_lock;
/*
* This is ugly, but we want the default case to fall through.
* "down_failed" is a special asm handler that calls the C
* routine that actually waits.
*/
static inline void down(struct semaphore *sem)
{
might_sleep();
if (atomic_dec_return(&sem->count) < 0)
__down(sem);
}
static inline int down_interruptible(struct semaphore *sem)
{
int ret = 0;
might_sleep();
if (atomic_dec_return(&sem->count) < 0)
ret = __down_interruptible(sem);
return (ret);
}
static inline int down_trylock(struct semaphore *sem)
{
int ret = 0;
if (atomic_dec_return(&sem->count) < 0)
ret = __down_trylock(sem);
return ret;
}
/*
* Note! This is subtle. We jump to wake people up only if
* the semaphore was negative (== somebody was waiting on it).
* The default case (no contention) will result in NO
* jumps for both down() and up().
*/
static inline void up(struct semaphore *sem)
{
if (atomic_inc_return(&sem->count) <= 0)
__up(sem);
}
#endif /* __ASSEMBLY__ */
#endif /* _BFIN_SEMAPHORE_H */
#include <linux/semaphore.h>
include/asm-cris/semaphore-helper.h deleted 100644 → 0
View file @ e48b3dee
/* $Id: semaphore-helper.h,v 1.3 2001/03/26 15:00:33 orjanf Exp $
*
* SMP- and interrupt-safe semaphores helper functions. Generic versions, no
* optimizations whatsoever...
*
*/
#ifndef _ASM_SEMAPHORE_HELPER_H
#define _ASM_SEMAPHORE_HELPER_H
#include <asm/atomic.h>
#include <linux/errno.h>
#define read(a) ((a)->counter)
#define inc(a) (((a)->counter)++)
#define dec(a) (((a)->counter)--)
#define count_inc(a) ((*(a))++)
/*
* These two _must_ execute atomically wrt each other.
*/
static inline void wake_one_more(struct semaphore * sem)
{
atomic_inc(&sem->waking);
}
static inline int waking_non_zero(struct semaphore *sem)
{
unsigned long flags;
int ret = 0;
local_irq_save(flags);
if (read(&sem->waking) > 0) {
dec(&sem->waking);
ret = 1;
}
local_irq_restore(flags);
return ret;
}
static inline int waking_non_zero_interruptible(struct semaphore *sem,
struct task_struct *tsk)
{
int ret = 0;
unsigned long flags;
local_irq_save(flags);
if (read(&sem->waking) > 0) {
dec(&sem->waking);
ret = 1;
} else if (signal_pending(tsk)) {
inc(&sem->count);
ret = -EINTR;
}
local_irq_restore(flags);
return ret;
}
static inline int waking_non_zero_trylock(struct semaphore *sem)
{
int ret = 1;
unsigned long flags;
local_irq_save(flags);
if (read(&sem->waking) <= 0)
inc(&sem->count);
else {
dec(&sem->waking);
ret = 0;
}
local_irq_restore(flags);
return ret;
}
#endif /* _ASM_SEMAPHORE_HELPER_H */
include/asm-cris/semaphore.h
View file @ 64ac24e7
/* $Id: semaphore.h,v 1.3 2001/05/08 13:54:09 bjornw Exp $ */
/* On the i386 these are coded in asm, perhaps we should as well. Later.. */
#ifndef _CRIS_SEMAPHORE_H
#define _CRIS_SEMAPHORE_H
#define RW_LOCK_BIAS 0x01000000
#include <linux/wait.h>
#include <linux/spinlock.h>
#include <linux/rwsem.h>
#include <asm/system.h>
#include <asm/atomic.h>
/*
* CRIS semaphores, implemented in C-only so far.
*/
struct semaphore {
atomic_t count;
atomic_t waking;
wait_queue_head_t wait;
};
#define __SEMAPHORE_INITIALIZER(name, n) \
{ \
.count = ATOMIC_INIT(n), \
.waking = ATOMIC_INIT(0), \
.wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \
}
#define __DECLARE_SEMAPHORE_GENERIC(name,count) \
struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
static inline void sema_init(struct semaphore *sem, int val)
{
*sem = (struct semaphore)__SEMAPHORE_INITIALIZER((*sem),val);
}
static inline void init_MUTEX (struct semaphore *sem)
{
sema_init(sem, 1);
}
static inline void init_MUTEX_LOCKED (struct semaphore *sem)
{
sema_init(sem, 0);
}
extern void __down(struct semaphore * sem);
extern int __down_interruptible(struct semaphore * sem);
extern int __down_trylock(struct semaphore * sem);
extern void __up(struct semaphore * sem);
/* notice - we probably can do cli/sti here instead of saving */
static inline void down(struct semaphore * sem)
{
unsigned long flags;
int failed;
might_sleep();
/* atomically decrement the semaphores count, and if its negative, we wait */
cris_atomic_save(sem, flags);
failed = --(sem->count.counter) < 0;
cris_atomic_restore(sem, flags);
if(failed) {
__down(sem);
}
}
/*
* This version waits in interruptible state so that the waiting
* process can be killed. The down_interruptible routine
* returns negative for signalled and zero for semaphore acquired.
*/
static inline int down_interruptible(struct semaphore * sem)
{
unsigned long flags;
int failed;
might_sleep();
/* atomically decrement the semaphores count, and if its negative, we wait */
cris_atomic_save(sem, flags);
failed = --(sem->count.counter) < 0;
cris_atomic_restore(sem, flags);
if(failed)
failed = __down_interruptible(sem);
return(failed);
}
static inline int down_trylock(struct semaphore * sem)
{
unsigned long flags;
int failed;
cris_atomic_save(sem, flags);
failed = --(sem->count.counter) < 0;
cris_atomic_restore(sem, flags);
if(failed)
failed = __down_trylock(sem);
return(failed);
}
/*
* Note! This is subtle. We jump to wake people up only if
* the semaphore was negative (== somebody was waiting on it).
* The default case (no contention) will result in NO
* jumps for both down() and up().
*/
static inline void up(struct semaphore * sem)
{
unsigned long flags;
int wakeup;
/* atomically increment the semaphores count, and if it was negative, we wake people */
cris_atomic_save(sem, flags);
wakeup = ++(sem->count.counter) <= 0;
cris_atomic_restore(sem, flags);
if(wakeup) {
__up(sem);
}
}
#endif
#include <linux/semaphore.h>
include/asm-frv/semaphore.h
View file @ 64ac24e7
/* semaphore.h: semaphores for the FR-V
*
* Copyright (C) 2003 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#ifndef _ASM_SEMAPHORE_H
#define _ASM_SEMAPHORE_H
#define RW_LOCK_BIAS 0x01000000
#ifndef __ASSEMBLY__
#include <linux/linkage.h>
#include <linux/wait.h>
#include <linux/spinlock.h>
#include <linux/rwsem.h>
/*
* the semaphore definition
* - if counter is >0 then there are tokens available on the semaphore for down to collect
* - if counter is <=0 then there are no spare tokens, and anyone that wants one must wait
* - if wait_list is not empty, then there are processes waiting for the semaphore
*/
struct semaphore {
unsigned counter;
spinlock_t wait_lock;
struct list_head wait_list;
#ifdef CONFIG_DEBUG_SEMAPHORE
unsigned __magic;
#endif
};
#ifdef CONFIG_DEBUG_SEMAPHORE
# define __SEM_DEBUG_INIT(name) , (long)&(name).__magic
#else
# define __SEM_DEBUG_INIT(name)
#endif
#define __SEMAPHORE_INITIALIZER(name,count) \
{ count, SPIN_LOCK_UNLOCKED, LIST_HEAD_INIT((name).wait_list) __SEM_DEBUG_INIT(name) }
#define __DECLARE_SEMAPHORE_GENERIC(name,count) \
struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
static inline void sema_init (struct semaphore *sem, int val)
{
*sem = (struct semaphore) __SEMAPHORE_INITIALIZER(*sem, val);
}
static inline void init_MUTEX (struct semaphore *sem)
{
sema_init(sem, 1);
}
static inline void init_MUTEX_LOCKED (struct semaphore *sem)
{
sema_init(sem, 0);
}
extern void __down(struct semaphore *sem, unsigned long flags);
extern int __down_interruptible(struct semaphore *sem, unsigned long flags);
extern void __up(struct semaphore *sem);
static inline void down(struct semaphore *sem)
{
unsigned long flags;
#ifdef CONFIG_DEBUG_SEMAPHORE
CHECK_MAGIC(sem->__magic);
#endif
spin_lock_irqsave(&sem->wait_lock, flags);
if (likely(sem->counter > 0)) {
sem->counter--;
spin_unlock_irqrestore(&sem->wait_lock, flags);
}
else {
__down(sem, flags);
}
}
static inline int down_interruptible(struct semaphore *sem)
{
unsigned long flags;
int ret = 0;
#ifdef CONFIG_DEBUG_SEMAPHORE
CHECK_MAGIC(sem->__magic);
#endif
spin_lock_irqsave(&sem->wait_lock, flags);
if (likely(sem->counter > 0)) {
sem->counter--;
spin_unlock_irqrestore(&sem->wait_lock, flags);
}
else {
ret = __down_interruptible(sem, flags);
}
return ret;
}
/*
* non-blockingly attempt to down() a semaphore.
* - returns zero if we acquired it
*/
static inline int down_trylock(struct semaphore *sem)
{
unsigned long flags;
int success = 0;
#ifdef CONFIG_DEBUG_SEMAPHORE
CHECK_MAGIC(sem->__magic);
#endif
spin_lock_irqsave(&sem->wait_lock, flags);
if (sem->counter > 0) {
sem->counter--;
success = 1;
}
spin_unlock_irqrestore(&sem->wait_lock, flags);
return !success;
}
static inline void up(struct semaphore *sem)
{
unsigned long flags;
#ifdef CONFIG_DEBUG_SEMAPHORE
CHECK_MAGIC(sem->__magic);
#endif
spin_lock_irqsave(&sem->wait_lock, flags);
if (!list_empty(&sem->wait_list))
__up(sem);
else
sem->counter++;
spin_unlock_irqrestore(&sem->wait_lock, flags);
}
static inline int sem_getcount(struct semaphore *sem)
{
return sem->counter;
}
#endif /* __ASSEMBLY__ */
#endif
#include <linux/semaphore.h>
include/asm-h8300/semaphore-helper.h deleted 100644 → 0
View file @ e48b3dee
#ifndef _H8300_SEMAPHORE_HELPER_H
#define _H8300_SEMAPHORE_HELPER_H
/*
* SMP- and interrupt-safe semaphores helper functions.
*
* (C) Copyright 1996 Linus Torvalds
*
* based on
* m68k version by Andreas Schwab
*/
#include <linux/errno.h>
/*
* These two _must_ execute atomically wrt each other.
*/
static inline void wake_one_more(struct semaphore * sem)
{
atomic_inc((atomic_t *)&sem->sleepers);
}
static inline int waking_non_zero(struct semaphore *sem)
{
int ret;
unsigned long flags;
spin_lock_irqsave(&semaphore_wake_lock, flags);
ret = 0;
if (sem->sleepers > 0) {
sem->sleepers--;
ret = 1;
}
spin_unlock_irqrestore(&semaphore_wake_lock, flags);
return ret;
}
/*
* waking_non_zero_interruptible:
* 1 got the lock
* 0 go to sleep
* -EINTR interrupted
*/
static inline int waking_non_zero_interruptible(struct semaphore *sem,
struct task_struct *tsk)
{
int ret;
unsigned long flags;
spin_lock_irqsave(&semaphore_wake_lock, flags);
ret = 0;
if (sem->sleepers > 0) {
sem->sleepers--;
ret = 1;
} else if (signal_pending(tsk)) {
atomic_inc(&sem->count);
ret = -EINTR;
}
spin_unlock_irqrestore(&semaphore_wake_lock, flags);
return ret;
}
/*
* waking_non_zero_trylock:
* 1 failed to lock
* 0 got the lock
*/
static inline int waking_non_zero_trylock(struct semaphore *sem)
{
int ret;
unsigned long flags;
spin_lock_irqsave(&semaphore_wake_lock, flags);
ret = 1;
if (sem->sleepers <= 0)
atomic_inc(&sem->count);
else {
sem->sleepers--;
ret = 0;
}
spin_unlock_irqrestore(&semaphore_wake_lock, flags);
return ret;
}
#endif
include/asm-h8300/semaphore.h
View file @ 64ac24e7
#ifndef _H8300_SEMAPHORE_H
#define _H8300_SEMAPHORE_H
#define RW_LOCK_BIAS 0x01000000
#ifndef __ASSEMBLY__
#include <linux/linkage.h>
#include <linux/wait.h>
#include <linux/spinlock.h>
#include <linux/rwsem.h>
#include <asm/system.h>
#include <asm/atomic.h>
/*
* Interrupt-safe semaphores..
*
* (C) Copyright 1996 Linus Torvalds
*
* H8/300 version by Yoshinori Sato
*/
struct semaphore {
atomic_t count;
int sleepers;
wait_queue_head_t wait;
};
#define __SEMAPHORE_INITIALIZER(name, n) \
{ \
.count = ATOMIC_INIT(n), \
.sleepers = 0, \
.wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \
}
#define __DECLARE_SEMAPHORE_GENERIC(name,count) \
struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
static inline void sema_init (struct semaphore *sem, int val)
{
*sem = (struct semaphore)__SEMAPHORE_INITIALIZER(*sem, val);
}
static inline void init_MUTEX (struct semaphore *sem)
{
sema_init(sem, 1);
}
static inline void init_MUTEX_LOCKED (struct semaphore *sem)
{
sema_init(sem, 0);
}
asmlinkage void __down_failed(void /* special register calling convention */);
asmlinkage int __down_failed_interruptible(void /* params in registers */);
asmlinkage int __down_failed_trylock(void /* params in registers */);
asmlinkage void __up_wakeup(void /* special register calling convention */);
asmlinkage void __down(struct semaphore * sem);
asmlinkage int __down_interruptible(struct semaphore * sem);
asmlinkage int __down_trylock(struct semaphore * sem);
asmlinkage void __up(struct semaphore * sem);
extern spinlock_t semaphore_wake_lock;
/*
* This is ugly, but we want the default case to fall through.
* "down_failed" is a special asm handler that calls the C
* routine that actually waits. See arch/m68k/lib/semaphore.S
*/
static inline void down(struct semaphore * sem)
{
register atomic_t *count asm("er0");
might_sleep();
count = &(sem->count);
__asm__ __volatile__(
"stc ccr,r3l\n\t"
"orc #0x80,ccr\n\t"
"mov.l %2, er1\n\t"
"dec.l #1,er1\n\t"
"mov.l er1,%0\n\t"
"bpl 1f\n\t"
"ldc r3l,ccr\n\t"
"mov.l %1,er0\n\t"
"jsr @___down\n\t"
"bra 2f\n"
"1:\n\t"
"ldc r3l,ccr\n"
"2:"
: "=m"(*count)
: "g"(sem),"m"(*count)
: "cc", "er1", "er2", "er3");
}
static inline int down_interruptible(struct semaphore * sem)
{
register atomic_t *count asm("er0");
might_sleep();
count = &(sem->count);
__asm__ __volatile__(
"stc ccr,r1l\n\t"
"orc #0x80,ccr\n\t"
"mov.l %3, er2\n\t"
"dec.l #1,er2\n\t"
"mov.l er2,%1\n\t"
"bpl 1f\n\t"
"ldc r1l,ccr\n\t"
"mov.l %2,er0\n\t"
"jsr @___down_interruptible\n\t"
"bra 2f\n"
"1:\n\t"
"ldc r1l,ccr\n\t"
"sub.l %0,%0\n\t"
"2:\n\t"
: "=r" (count),"=m" (*count)
: "g"(sem),"m"(*count)
: "cc", "er1", "er2", "er3");
return (int)count;
}
static inline int down_trylock(struct semaphore * sem)
{
register atomic_t *count asm("er0");
count = &(sem->count);
__asm__ __volatile__(
"stc ccr,r3l\n\t"
"orc #0x80,ccr\n\t"
"mov.l %3,er2\n\t"
"dec.l #1,er2\n\t"
"mov.l er2,%0\n\t"
"bpl 1f\n\t"
"ldc r3l,ccr\n\t"
"jmp @3f\n\t"
LOCK_SECTION_START(".align 2\n\t")
"3:\n\t"
"mov.l %2,er0\n\t"
"jsr @___down_trylock\n\t"
"jmp @2f\n\t"
LOCK_SECTION_END
"1:\n\t"
"ldc r3l,ccr\n\t"
"sub.l %1,%1\n"
"2:"
: "=m" (*count),"=r"(count)
: "g"(sem),"m"(*count)
: "cc", "er1","er2", "er3");
return (int)count;
}
/*
* Note! This is subtle. We jump to wake people up only if
* the semaphore was negative (== somebody was waiting on it).
* The default case (no contention) will result in NO
* jumps for both down() and up().
*/
static inline void up(struct semaphore * sem)
{
register atomic_t *count asm("er0");
count = &(sem->count);
__asm__ __volatile__(
"stc ccr,r3l\n\t"
"orc #0x80,ccr\n\t"
"mov.l %2,er1\n\t"
"inc.l #1,er1\n\t"
"mov.l er1,%0\n\t"
"ldc r3l,ccr\n\t"
"sub.l er2,er2\n\t"
"cmp.l er2,er1\n\t"
"bgt 1f\n\t"
"mov.l %1,er0\n\t"
"jsr @___up\n"
"1:"
: "=m"(*count)
: "g"(sem),"m"(*count)
: "cc", "er1", "er2", "er3");
}
#endif /* __ASSEMBLY__ */
#endif
#include <linux/semaphore.h>
include/asm-ia64/semaphore.h
View file @ 64ac24e7
#ifndef _ASM_IA64_SEMAPHORE_H
#define _ASM_IA64_SEMAPHORE_H
/*
* Copyright (C) 1998-2000 Hewlett-Packard Co
* Copyright (C) 1998-2000 David Mosberger-Tang <davidm@hpl.hp.com>
*/
#include <linux/wait.h>
#include <linux/rwsem.h>
#include <asm/atomic.h>
struct semaphore {
atomic_t count;
int sleepers;
wait_queue_head_t wait;
};
#define __SEMAPHORE_INITIALIZER(name, n) \
{ \
.count = ATOMIC_INIT(n), \
.sleepers = 0, \
.wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \
}
#define __DECLARE_SEMAPHORE_GENERIC(name,count) \
struct semaphore name = __SEMAPHORE_INITIALIZER(name, count)
#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name, 1)
static inline void
sema_init (struct semaphore *sem, int val)
{
*sem = (struct semaphore) __SEMAPHORE_INITIALIZER(*sem, val);
}
static inline void
init_MUTEX (struct semaphore *sem)
{
sema_init(sem, 1);
}
static inline void
init_MUTEX_LOCKED (struct semaphore *sem)
{
sema_init(sem, 0);
}
extern void __down (struct semaphore * sem);
extern int __down_interruptible (struct semaphore * sem);
extern int __down_trylock (struct semaphore * sem);
extern void __up (struct semaphore * sem);
/*
* Atomically decrement the semaphore's count. If it goes negative,
* block the calling thread in the TASK_UNINTERRUPTIBLE state.
*/
static inline void
down (struct semaphore *sem)
{
might_sleep();
if (ia64_fetchadd(-1, &sem->count.counter, acq) < 1)
__down(sem);
}
/*
* Atomically decrement the semaphore's count. If it goes negative,
* block the calling thread in the TASK_INTERRUPTIBLE state.
*/
static inline int
down_interruptible (struct semaphore * sem)
{
int ret = 0;
might_sleep();
if (ia64_fetchadd(-1, &sem->count.counter, acq) < 1)
ret = __down_interruptible(sem);
return ret;
}
static inline int
down_trylock (struct semaphore *sem)
{
int ret = 0;
if (ia64_fetchadd(-1, &sem->count.counter, acq) < 1)
ret = __down_trylock(sem);
return ret;
}
static inline void
up (struct semaphore * sem)
{
if (ia64_fetchadd(1, &sem->count.counter, rel) <= -1)
__up(sem);
}
#endif /* _ASM_IA64_SEMAPHORE_H */
#include <linux/semaphore.h>
include/asm-m32r/semaphore.h
View file @ 64ac24e7
#ifndef _ASM_M32R_SEMAPHORE_H
#define _ASM_M32R_SEMAPHORE_H
#include <linux/linkage.h>
#ifdef __KERNEL__
/*
* SMP- and interrupt-safe semaphores..
*
* Copyright (C) 1996 Linus Torvalds
* Copyright (C) 2004, 2006 Hirokazu Takata <takata at linux-m32r.org>
*/
#include <linux/wait.h>
#include <linux/rwsem.h>
#include <asm/assembler.h>
#include <asm/system.h>
#include <asm/atomic.h>
struct semaphore {
atomic_t count;
int sleepers;
wait_queue_head_t wait;
};
#define __SEMAPHORE_INITIALIZER(name, n) \
{ \
.count = ATOMIC_INIT(n), \
.sleepers = 0, \
.wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \
}
#define __DECLARE_SEMAPHORE_GENERIC(name,count) \
struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
static inline void sema_init (struct semaphore *sem, int val)
{
/*
* *sem = (struct semaphore)__SEMAPHORE_INITIALIZER((*sem),val);
*
* i'd rather use the more flexible initialization above, but sadly
* GCC 2.7.2.3 emits a bogus warning. EGCS doesnt. Oh well.
*/
atomic_set(&sem->count, val);
sem->sleepers = 0;
init_waitqueue_head(&sem->wait);
}
static inline void init_MUTEX (struct semaphore *sem)
{
sema_init(sem, 1);
}
static inline void init_MUTEX_LOCKED (struct semaphore *sem)
{
sema_init(sem, 0);
}
asmlinkage void __down_failed(void /* special register calling convention */);
asmlinkage int __down_failed_interruptible(void /* params in registers */);
asmlinkage int __down_failed_trylock(void /* params in registers */);
asmlinkage void __up_wakeup(void /* special register calling convention */);
asmlinkage void __down(struct semaphore * sem);
asmlinkage int __down_interruptible(struct semaphore * sem);
asmlinkage int __down_trylock(struct semaphore * sem);
asmlinkage void __up(struct semaphore * sem);
/*
* Atomically decrement the semaphore's count. If it goes negative,
* block the calling thread in the TASK_UNINTERRUPTIBLE state.
*/
static inline void down(struct semaphore * sem)
{
might_sleep();
if (unlikely(atomic_dec_return(&sem->count) < 0))
__down(sem);
}
/*
* Interruptible try to acquire a semaphore. If we obtained
* it, return zero. If we were interrupted, returns -EINTR
*/
static inline int down_interruptible(struct semaphore * sem)
{
int result = 0;
might_sleep();
if (unlikely(atomic_dec_return(&sem->count) < 0))
result = __down_interruptible(sem);
return result;
}
/*
* Non-blockingly attempt to down() a semaphore.
* Returns zero if we acquired it
*/
static inline int down_trylock(struct semaphore * sem)
{
unsigned long flags;
long count;
int result = 0;
local_irq_save(flags);
__asm__ __volatile__ (
"# down_trylock \n\t"
DCACHE_CLEAR("%0", "r4", "%1")
M32R_LOCK" %0, @%1; \n\t"
"addi %0, #-1; \n\t"
M32R_UNLOCK" %0, @%1; \n\t"
: "=&r" (count)
: "r" (&sem->count)
: "memory"
#ifdef CONFIG_CHIP_M32700_TS1
, "r4"
#endif /* CONFIG_CHIP_M32700_TS1 */
);
local_irq_restore(flags);
if (unlikely(count < 0))
result = __down_trylock(sem);
return result;
}
/*
* Note! This is subtle. We jump to wake people up only if
* the semaphore was negative (== somebody was waiting on it).
* The default case (no contention) will result in NO
* jumps for both down() and up().
*/
static inline void up(struct semaphore * sem)
{
if (unlikely(atomic_inc_return(&sem->count) <= 0))
__up(sem);
}
#endif /* __KERNEL__ */
#endif /* _ASM_M32R_SEMAPHORE_H */
#include <linux/semaphore.h>
include/asm-m68k/semaphore-helper.h deleted 100644 → 0
View file @ e48b3dee
#ifndef _M68K_SEMAPHORE_HELPER_H
#define _M68K_SEMAPHORE_HELPER_H
/*
* SMP- and interrupt-safe semaphores helper functions.
*
* (C) Copyright 1996 Linus Torvalds
*
* m68k version by Andreas Schwab
*/
#include <linux/errno.h>
/*
* These two _must_ execute atomically wrt each other.
*/
static inline void wake_one_more(struct semaphore * sem)
{
atomic_inc(&sem->waking);
}
#ifndef CONFIG_RMW_INSNS
extern spinlock_t semaphore_wake_lock;
#endif
static inline int waking_non_zero(struct semaphore *sem)
{
int ret;
#ifndef CONFIG_RMW_INSNS
unsigned long flags;
spin_lock_irqsave(&semaphore_wake_lock, flags);
ret = 0;
if (atomic_read(&sem->waking) > 0) {
atomic_dec(&sem->waking);
ret = 1;
}
spin_unlock_irqrestore(&semaphore_wake_lock, flags);
#else
int tmp1, tmp2;
__asm__ __volatile__
("1: movel %1,%2\n"
" jle 2f\n"
" subql #1,%2\n"
" casl %1,%2,%3\n"
" jne 1b\n"
" moveq #1,%0\n"
"2:"
: "=d" (ret), "=d" (tmp1), "=d" (tmp2)
: "m" (sem->waking), "0" (0), "1" (sem->waking));
#endif
return ret;
}
/*
* waking_non_zero_interruptible:
* 1 got the lock
* 0 go to sleep
* -EINTR interrupted
*/
static inline int waking_non_zero_interruptible(struct semaphore *sem,
struct task_struct *tsk)
{
int ret;
#ifndef CONFIG_RMW_INSNS
unsigned long flags;
spin_lock_irqsave(&semaphore_wake_lock, flags);
ret = 0;
if (atomic_read(&sem->waking) > 0) {
atomic_dec(&sem->waking);
ret = 1;
} else if (signal_pending(tsk)) {
atomic_inc(&sem->count);
ret = -EINTR;
}
spin_unlock_irqrestore(&semaphore_wake_lock, flags);
#else
int tmp1, tmp2;
__asm__ __volatile__
("1: movel %1,%2\n"
" jle 2f\n"
" subql #1,%2\n"
" casl %1,%2,%3\n"
" jne 1b\n"
" moveq #1,%0\n"
" jra %a4\n"
"2:"
: "=d" (ret), "=d" (tmp1), "=d" (tmp2)
: "m" (sem->waking), "i" (&&next), "0" (0), "1" (sem->waking));
if (signal_pending(tsk)) {
atomic_inc(&sem->count);
ret = -EINTR;
}
next:
#endif
return ret;
}
/*
* waking_non_zero_trylock:
* 1 failed to lock
* 0 got the lock
*/
static inline int waking_non_zero_trylock(struct semaphore *sem)
{
int ret;
#ifndef CONFIG_RMW_INSNS
unsigned long flags;
spin_lock_irqsave(&semaphore_wake_lock, flags);
ret = 1;
if (atomic_read(&sem->waking) > 0) {
atomic_dec(&sem->waking);
ret = 0;
} else
atomic_inc(&sem->count);
spin_unlock_irqrestore(&semaphore_wake_lock, flags);
#else
int tmp1, tmp2;
__asm__ __volatile__
("1: movel %1,%2\n"
" jle 2f\n"
" subql #1,%2\n"
" casl %1,%2,%3\n"
" jne 1b\n"
" moveq #0,%0\n"
"2:"
: "=d" (ret), "=d" (tmp1), "=d" (tmp2)
: "m" (sem->waking), "0" (1), "1" (sem->waking));
if (ret)
atomic_inc(&sem->count);
#endif
return ret;
}
#endif
include/asm-m68k/semaphore.h
View file @ 64ac24e7
#ifndef _M68K_SEMAPHORE_H
#define _M68K_SEMAPHORE_H
#define RW_LOCK_BIAS 0x01000000
#ifndef __ASSEMBLY__
#include <linux/linkage.h>
#include <linux/wait.h>
#include <linux/spinlock.h>
#include <linux/rwsem.h>
#include <linux/stringify.h>
#include <asm/system.h>
#include <asm/atomic.h>
/*
* Interrupt-safe semaphores..
*
* (C) Copyright 1996 Linus Torvalds
*
* m68k version by Andreas Schwab
*/
struct semaphore {
atomic_t count;
atomic_t waking;
wait_queue_head_t wait;
};
#define __SEMAPHORE_INITIALIZER(name, n) \
{ \
.count = ATOMIC_INIT(n), \
.waking = ATOMIC_INIT(0), \
.wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \
}
#define __DECLARE_SEMAPHORE_GENERIC(name,count) \
struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
static inline void sema_init(struct semaphore *sem, int val)
{
*sem = (struct semaphore)__SEMAPHORE_INITIALIZER(*sem, val);
}
static inline void init_MUTEX (struct semaphore *sem)
{
sema_init(sem, 1);
}
static inline void init_MUTEX_LOCKED (struct semaphore *sem)
{
sema_init(sem, 0);
}
asmlinkage void __down_failed(void /* special register calling convention */);
asmlinkage int __down_failed_interruptible(void /* params in registers */);
asmlinkage int __down_failed_trylock(void /* params in registers */);
asmlinkage void __up_wakeup(void /* special register calling convention */);
asmlinkage void __down(struct semaphore * sem);
asmlinkage int __down_interruptible(struct semaphore * sem);
asmlinkage int __down_trylock(struct semaphore * sem);
asmlinkage void __up(struct semaphore * sem);
/*
* This is ugly, but we want the default case to fall through.
* "down_failed" is a special asm handler that calls the C
* routine that actually waits. See arch/m68k/lib/semaphore.S
*/
static inline void down(struct semaphore *sem)
{
register struct semaphore *sem1 __asm__ ("%a1") = sem;
might_sleep();
__asm__ __volatile__(
"| atomic down operation\n\t"
"subql #1,%0@\n\t"
"jmi 2f\n\t"
"1:\n"
LOCK_SECTION_START(".even\n\t")
"2:\tpea 1b\n\t"
"jbra __down_failed\n"
LOCK_SECTION_END
: /* no outputs */
: "a" (sem1)
: "memory");
}
static inline int down_interruptible(struct semaphore *sem)
{
register struct semaphore *sem1 __asm__ ("%a1") = sem;
register int result __asm__ ("%d0");
might_sleep();
__asm__ __volatile__(
"| atomic interruptible down operation\n\t"
"subql #1,%1@\n\t"
"jmi 2f\n\t"
"clrl %0\n"
"1:\n"
LOCK_SECTION_START(".even\n\t")
"2:\tpea 1b\n\t"
"jbra __down_failed_interruptible\n"
LOCK_SECTION_END
: "=d" (result)
: "a" (sem1)
: "memory");
return result;
}
static inline int down_trylock(struct semaphore *sem)
{
register struct semaphore *sem1 __asm__ ("%a1") = sem;
register int result __asm__ ("%d0");
__asm__ __volatile__(
"| atomic down trylock operation\n\t"
"subql #1,%1@\n\t"
"jmi 2f\n\t"
"clrl %0\n"
"1:\n"
LOCK_SECTION_START(".even\n\t")
"2:\tpea 1b\n\t"
"jbra __down_failed_trylock\n"
LOCK_SECTION_END
: "=d" (result)
: "a" (sem1)
: "memory");
return result;
}
/*
* Note! This is subtle. We jump to wake people up only if
* the semaphore was negative (== somebody was waiting on it).
* The default case (no contention) will result in NO
* jumps for both down() and up().
*/
static inline void up(struct semaphore *sem)
{
register struct semaphore *sem1 __asm__ ("%a1") = sem;
__asm__ __volatile__(
"| atomic up operation\n\t"
"addql #1,%0@\n\t"
"jle 2f\n"
"1:\n"
LOCK_SECTION_START(".even\n\t")
"2:\t"
"pea 1b\n\t"
"jbra __up_wakeup\n"
LOCK_SECTION_END
: /* no outputs */
: "a" (sem1)
: "memory");
}
#endif /* __ASSEMBLY__ */
#endif
#include <linux/semaphore.h>
include/asm-m68knommu/semaphore-helper.h deleted 100644 → 0
View file @ e48b3dee
#ifndef _M68K_SEMAPHORE_HELPER_H
#define _M68K_SEMAPHORE_HELPER_H
/*
* SMP- and interrupt-safe semaphores helper functions.
*
* (C) Copyright 1996 Linus Torvalds
*
* m68k version by Andreas Schwab
*/
/*
* These two _must_ execute atomically wrt each other.
*/
static inline void wake_one_more(struct semaphore * sem)
{
atomic_inc(&sem->waking);
}
static inline int waking_non_zero(struct semaphore *sem)
{
int ret;
unsigned long flags;
spin_lock_irqsave(&semaphore_wake_lock, flags);
ret = 0;
if (atomic_read(&sem->waking) > 0) {
atomic_dec(&sem->waking);
ret = 1;
}
spin_unlock_irqrestore(&semaphore_wake_lock, flags);
return ret;
}
/*
* waking_non_zero_interruptible:
* 1 got the lock
* 0 go to sleep
* -EINTR interrupted
*/
static inline int waking_non_zero_interruptible(struct semaphore *sem,
struct task_struct *tsk)
{
int ret;
unsigned long flags;
spin_lock_irqsave(&semaphore_wake_lock, flags);
ret = 0;
if (atomic_read(&sem->waking) > 0) {
atomic_dec(&sem->waking);
ret = 1;
} else if (signal_pending(tsk)) {
atomic_inc(&sem->count);
ret = -EINTR;
}
spin_unlock_irqrestore(&semaphore_wake_lock, flags);
return ret;
}
/*
* waking_non_zero_trylock:
* 1 failed to lock
* 0 got the lock
*/
static inline int waking_non_zero_trylock(struct semaphore *sem)
{
int ret;
unsigned long flags;
spin_lock_irqsave(&semaphore_wake_lock, flags);
ret = 1;
if (atomic_read(&sem->waking) > 0) {
atomic_dec(&sem->waking);
ret = 0;
} else
atomic_inc(&sem->count);
spin_unlock_irqrestore(&semaphore_wake_lock, flags);
return ret;
}
#endif
include/asm-m68knommu/semaphore.h
View file @ 64ac24e7
#ifndef _M68K_SEMAPHORE_H
#define _M68K_SEMAPHORE_H
#define RW_LOCK_BIAS 0x01000000
#ifndef __ASSEMBLY__
#include <linux/linkage.h>
#include <linux/wait.h>
#include <linux/spinlock.h>
#include <linux/rwsem.h>
#include <asm/system.h>
#include <asm/atomic.h>
/*
* Interrupt-safe semaphores..
*
* (C) Copyright 1996 Linus Torvalds
*
* m68k version by Andreas Schwab
*/
struct semaphore {
atomic_t count;
atomic_t waking;
wait_queue_head_t wait;
};
#define __SEMAPHORE_INITIALIZER(name, n) \
{ \
.count = ATOMIC_INIT(n), \
.waking = ATOMIC_INIT(0), \
.wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \
}
#define __DECLARE_SEMAPHORE_GENERIC(name,count) \
struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
static inline void sema_init (struct semaphore *sem, int val)
{
*sem = (struct semaphore)__SEMAPHORE_INITIALIZER(*sem, val);
}
static inline void init_MUTEX (struct semaphore *sem)
{
sema_init(sem, 1);
}
static inline void init_MUTEX_LOCKED (struct semaphore *sem)
{
sema_init(sem, 0);
}
asmlinkage void __down_failed(void /* special register calling convention */);
asmlinkage int __down_failed_interruptible(void /* params in registers */);
asmlinkage int __down_failed_trylock(void /* params in registers */);
asmlinkage void __up_wakeup(void /* special register calling convention */);
asmlinkage void __down(struct semaphore * sem);
asmlinkage int __down_interruptible(struct semaphore * sem);
asmlinkage int __down_trylock(struct semaphore * sem);
asmlinkage void __up(struct semaphore * sem);
extern spinlock_t semaphore_wake_lock;
/*
* This is ugly, but we want the default case to fall through.
* "down_failed" is a special asm handler that calls the C
* routine that actually waits. See arch/m68k/lib/semaphore.S
*/
static inline void down(struct semaphore * sem)
{
might_sleep();
__asm__ __volatile__(
"| atomic down operation\n\t"
"movel %0, %%a1\n\t"
"lea %%pc@(1f), %%a0\n\t"
"subql #1, %%a1@\n\t"
"jmi __down_failed\n"
"1:"
: /* no outputs */
: "g" (sem)
: "cc", "%a0", "%a1", "memory");
}
static inline int down_interruptible(struct semaphore * sem)
{
int ret;
might_sleep();
__asm__ __volatile__(
"| atomic down operation\n\t"
"movel %1, %%a1\n\t"
"lea %%pc@(1f), %%a0\n\t"
"subql #1, %%a1@\n\t"
"jmi __down_failed_interruptible\n\t"
"clrl %%d0\n"
"1: movel %%d0, %0\n"
: "=d" (ret)
: "g" (sem)
: "cc", "%d0", "%a0", "%a1", "memory");
return(ret);
}
static inline int down_trylock(struct semaphore * sem)
{
register struct semaphore *sem1 __asm__ ("%a1") = sem;
register int result __asm__ ("%d0");
__asm__ __volatile__(
"| atomic down trylock operation\n\t"
"subql #1,%1@\n\t"
"jmi 2f\n\t"
"clrl %0\n"
"1:\n"
".section .text.lock,\"ax\"\n"
".even\n"
"2:\tpea 1b\n\t"
"jbra __down_failed_trylock\n"
".previous"
: "=d" (result)
: "a" (sem1)
: "memory");
return result;
}
/*
* Note! This is subtle. We jump to wake people up only if
* the semaphore was negative (== somebody was waiting on it).
* The default case (no contention) will result in NO
* jumps for both down() and up().
*/
static inline void up(struct semaphore * sem)
{
__asm__ __volatile__(
"| atomic up operation\n\t"
"movel %0, %%a1\n\t"
"lea %%pc@(1f), %%a0\n\t"
"addql #1, %%a1@\n\t"
"jle __up_wakeup\n"
"1:"
: /* no outputs */
: "g" (sem)
: "cc", "%a0", "%a1", "memory");
}
#endif /* __ASSEMBLY__ */
#endif
#include <linux/semaphore.h>
include/asm-mips/semaphore.h
View file @ 64ac24e7
/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 1996 Linus Torvalds
* Copyright (C) 1998, 99, 2000, 01, 04 Ralf Baechle
* Copyright (C) 1999, 2000, 01 Silicon Graphics, Inc.
* Copyright (C) 2000, 01 MIPS Technologies, Inc.
*
* In all honesty, little of the old MIPS code left - the PPC64 variant was
* just looking nice and portable so I ripped it. Credits to whoever wrote
* it.
*/
#ifndef __ASM_SEMAPHORE_H
#define __ASM_SEMAPHORE_H
/*
* Remove spinlock-based RW semaphores; RW semaphore definitions are
* now in rwsem.h and we use the generic lib/rwsem.c implementation.
* Rework semaphores to use atomic_dec_if_positive.
* -- Paul Mackerras (paulus@samba.org)
*/
#ifdef __KERNEL__
#include <asm/atomic.h>
#include <asm/system.h>
#include <linux/wait.h>
#include <linux/rwsem.h>
struct semaphore {
/*
* Note that any negative value of count is equivalent to 0,
* but additionally indicates that some process(es) might be
* sleeping on `wait'.
*/
atomic_t count;
wait_queue_head_t wait;
};
#define __SEMAPHORE_INITIALIZER(name, n) \
{ \
.count = ATOMIC_INIT(n), \
.wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \
}
#define __DECLARE_SEMAPHORE_GENERIC(name, count) \
struct semaphore name = __SEMAPHORE_INITIALIZER(name, count)
#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name, 1)
static inline void sema_init(struct semaphore *sem, int val)
{
atomic_set(&sem->count, val);
init_waitqueue_head(&sem->wait);
}
static inline void init_MUTEX(struct semaphore *sem)
{
sema_init(sem, 1);
}
static inline void init_MUTEX_LOCKED(struct semaphore *sem)
{
sema_init(sem, 0);
}
extern void __down(struct semaphore * sem);
extern int __down_interruptible(struct semaphore * sem);
extern void __up(struct semaphore * sem);
static inline void down(struct semaphore * sem)
{
might_sleep();
/*
* Try to get the semaphore, take the slow path if we fail.
*/
if (unlikely(atomic_dec_return(&sem->count) < 0))
__down(sem);
}
static inline int down_interruptible(struct semaphore * sem)
{
int ret = 0;
might_sleep();
if (unlikely(atomic_dec_return(&sem->count) < 0))
ret = __down_interruptible(sem);
return ret;
}
static inline int down_trylock(struct semaphore * sem)
{
return atomic_dec_if_positive(&sem->count) < 0;
}
static inline void up(struct semaphore * sem)
{
if (unlikely(atomic_inc_return(&sem->count) <= 0))
__up(sem);
}
#endif /* __KERNEL__ */
#endif /* __ASM_SEMAPHORE_H */
#include <linux/semaphore.h>
include/asm-mn10300/semaphore.h
View file @ 64ac24e7
/* MN10300 Semaphores
*
* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public Licence
* as published by the Free Software Foundation; either version
* 2 of the Licence, or (at your option) any later version.
*/
#ifndef _ASM_SEMAPHORE_H
#define _ASM_SEMAPHORE_H
#ifndef __ASSEMBLY__
#include <linux/linkage.h>
#include <linux/wait.h>
#include <linux/spinlock.h>
#include <linux/rwsem.h>
#define SEMAPHORE_DEBUG 0
/*
* the semaphore definition
* - if count is >0 then there are tokens available on the semaphore for down
* to collect
* - if count is <=0 then there are no spare tokens, and anyone that wants one
* must wait
* - if wait_list is not empty, then there are processes waiting for the
* semaphore
*/
struct semaphore {
atomic_t count; /* it's not really atomic, it's
* just that certain modules
* expect to be able to access
* it directly */
spinlock_t wait_lock;
struct list_head wait_list;
#if SEMAPHORE_DEBUG
unsigned __magic;
#endif
};
#if SEMAPHORE_DEBUG
# define __SEM_DEBUG_INIT(name) , (long)&(name).__magic
#else
# define __SEM_DEBUG_INIT(name)
#endif
#define __SEMAPHORE_INITIALIZER(name, init_count) \
{ \
.count = ATOMIC_INIT(init_count), \
.wait_lock = __SPIN_LOCK_UNLOCKED((name).wait_lock), \
.wait_list = LIST_HEAD_INIT((name).wait_list) \
__SEM_DEBUG_INIT(name) \
}
#define __DECLARE_SEMAPHORE_GENERIC(name,count) \
struct semaphore name = __SEMAPHORE_INITIALIZER(name, count)
#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name, 1)
#define DECLARE_MUTEX_LOCKED(name) __DECLARE_SEMAPHORE_GENERIC(name, 0)
static inline void sema_init(struct semaphore *sem, int val)
{
*sem = (struct semaphore) __SEMAPHORE_INITIALIZER(*sem, val);
}
static inline void init_MUTEX(struct semaphore *sem)
{
sema_init(sem, 1);
}
static inline void init_MUTEX_LOCKED(struct semaphore *sem)
{
sema_init(sem, 0);
}
extern void __down(struct semaphore *sem, unsigned long flags);
extern int __down_interruptible(struct semaphore *sem, unsigned long flags);
extern void __up(struct semaphore *sem);
static inline void down(struct semaphore *sem)
{
unsigned long flags;
int count;
#if SEMAPHORE_DEBUG
CHECK_MAGIC(sem->__magic);
#endif
spin_lock_irqsave(&sem->wait_lock, flags);
count = atomic_read(&sem->count);
if (likely(count > 0)) {
atomic_set(&sem->count, count - 1);
spin_unlock_irqrestore(&sem->wait_lock, flags);
} else {
__down(sem, flags);
}
}
static inline int down_interruptible(struct semaphore *sem)
{
unsigned long flags;
int count, ret = 0;
#if SEMAPHORE_DEBUG
CHECK_MAGIC(sem->__magic);
#endif
spin_lock_irqsave(&sem->wait_lock, flags);
count = atomic_read(&sem->count);
if (likely(count > 0)) {
atomic_set(&sem->count, count - 1);
spin_unlock_irqrestore(&sem->wait_lock, flags);
} else {
ret = __down_interruptible(sem, flags);
}
return ret;
}
/*
* non-blockingly attempt to down() a semaphore.
* - returns zero if we acquired it
*/
static inline int down_trylock(struct semaphore *sem)
{
unsigned long flags;
int count, success = 0;
#if SEMAPHORE_DEBUG
CHECK_MAGIC(sem->__magic);
#endif
spin_lock_irqsave(&sem->wait_lock, flags);
count = atomic_read(&sem->count);
if (likely(count > 0)) {
atomic_set(&sem->count, count - 1);
success = 1;
}
spin_unlock_irqrestore(&sem->wait_lock, flags);
return !success;
}
static inline void up(struct semaphore *sem)
{
unsigned long flags;
#if SEMAPHORE_DEBUG
CHECK_MAGIC(sem->__magic);
#endif
spin_lock_irqsave(&sem->wait_lock, flags);
if (!list_empty(&sem->wait_list))
__up(sem);
else
atomic_set(&sem->count, atomic_read(&sem->count) + 1);
spin_unlock_irqrestore(&sem->wait_lock, flags);
}
static inline int sem_getcount(struct semaphore *sem)
{
return atomic_read(&sem->count);
}
#endif /* __ASSEMBLY__ */
#endif
#include <linux/semaphore.h>
include/asm-parisc/semaphore-helper.h deleted 100644 → 0
View file @ e48b3dee
#ifndef _ASM_PARISC_SEMAPHORE_HELPER_H
#define _ASM_PARISC_SEMAPHORE_HELPER_H
/*
* SMP- and interrupt-safe semaphores helper functions.
*
* (C) Copyright 1996 Linus Torvalds
* (C) Copyright 1999 Andrea Arcangeli
*/
/*
* These two _must_ execute atomically wrt each other.
*
* This is trivially done with load_locked/store_cond,
* which we have. Let the rest of the losers suck eggs.
*/
static __inline__ void wake_one_more(struct semaphore * sem)
{
atomic_inc((atomic_t *)&sem->waking);
}
static __inline__ int waking_non_zero(struct semaphore *sem)
{
unsigned long flags;
int ret = 0;
spin_lock_irqsave(&semaphore_wake_lock, flags);
if (sem->waking > 0) {
sem->waking--;
ret = 1;
}
spin_unlock_irqrestore(&semaphore_wake_lock, flags);
return ret;
}
/*
* waking_non_zero_interruptible:
* 1 got the lock
* 0 go to sleep
* -EINTR interrupted
*
* We must undo the sem->count down_interruptible() increment while we are
* protected by the spinlock in order to make atomic this atomic_inc() with the
* atomic_read() in wake_one_more(), otherwise we can race. -arca
*/
static __inline__ int waking_non_zero_interruptible(struct semaphore *sem,
struct task_struct *tsk)
{
unsigned long flags;
int ret = 0;
spin_lock_irqsave(&semaphore_wake_lock, flags);
if (sem->waking > 0) {
sem->waking--;
ret = 1;
} else if (signal_pending(tsk)) {
atomic_inc(&sem->count);
ret = -EINTR;
}
spin_unlock_irqrestore(&semaphore_wake_lock, flags);
return ret;
}
/*
* waking_non_zero_trylock:
* 1 failed to lock
* 0 got the lock
*
* We must undo the sem->count down_trylock() increment while we are
* protected by the spinlock in order to make atomic this atomic_inc() with the
* atomic_read() in wake_one_more(), otherwise we can race. -arca
*/
static __inline__ int waking_non_zero_trylock(struct semaphore *sem)
{
unsigned long flags;
int ret = 1;
spin_lock_irqsave(&semaphore_wake_lock, flags);
if (sem->waking <= 0)
atomic_inc(&sem->count);
else {
sem->waking--;
ret = 0;
}
spin_unlock_irqrestore(&semaphore_wake_lock, flags);
return ret;
}
#endif /* _ASM_PARISC_SEMAPHORE_HELPER_H */
include/asm-parisc/semaphore.h
View file @ 64ac24e7
/* SMP- and interrupt-safe semaphores.
* PA-RISC version by Matthew Wilcox
*
* Linux/PA-RISC Project (http://www.parisc-linux.org/)
* Copyright (C) 1996 Linus Torvalds
* Copyright (C) 1999-2001 Matthew Wilcox < willy at debian d0T org >
* Copyright (C) 2000 Grant Grundler < grundler a debian org >
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#ifndef _ASM_PARISC_SEMAPHORE_H
#define _ASM_PARISC_SEMAPHORE_H
#include <linux/spinlock.h>
#include <linux/wait.h>
#include <linux/rwsem.h>
#include <asm/system.h>
/*
* The `count' is initialised to the number of people who are allowed to
* take the lock. (Normally we want a mutex, so this is `1'). if
* `count' is positive, the lock can be taken. if it's 0, no-one is
* waiting on it. if it's -1, at least one task is waiting.
*/
struct semaphore {
spinlock_t sentry;
int count;
wait_queue_head_t wait;
};
#define __SEMAPHORE_INITIALIZER(name, n) \
{ \
.sentry = SPIN_LOCK_UNLOCKED, \
.count = n, \
.wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \
}
#define __DECLARE_SEMAPHORE_GENERIC(name,count) \
struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
static inline void sema_init (struct semaphore *sem, int val)
{
*sem = (struct semaphore)__SEMAPHORE_INITIALIZER((*sem),val);
}
static inline void init_MUTEX (struct semaphore *sem)
{
sema_init(sem, 1);
}
static inline void init_MUTEX_LOCKED (struct semaphore *sem)
{
sema_init(sem, 0);
}
static inline int sem_getcount(struct semaphore *sem)
{
return sem->count;
}
asmlinkage void __down(struct semaphore * sem);
asmlinkage int __down_interruptible(struct semaphore * sem);
asmlinkage void __up(struct semaphore * sem);
/* Semaphores can be `tried' from irq context. So we have to disable
* interrupts while we're messing with the semaphore. Sorry.
*/
static inline void down(struct semaphore * sem)
{
might_sleep();
spin_lock_irq(&sem->sentry);
if (sem->count > 0) {
sem->count--;
} else {
__down(sem);
}
spin_unlock_irq(&sem->sentry);
}
static inline int down_interruptible(struct semaphore * sem)
{
int ret = 0;
might_sleep();
spin_lock_irq(&sem->sentry);
if (sem->count > 0) {
sem->count--;
} else {
ret = __down_interruptible(sem);
}
spin_unlock_irq(&sem->sentry);
return ret;
}
/*
* down_trylock returns 0 on success, 1 if we failed to get the lock.
* May not sleep, but must preserve irq state
*/
static inline int down_trylock(struct semaphore * sem)
{
unsigned long flags;
int count;
spin_lock_irqsave(&sem->sentry, flags);
count = sem->count - 1;
if (count >= 0)
sem->count = count;
spin_unlock_irqrestore(&sem->sentry, flags);
return (count < 0);
}
/*
* Note! This is subtle. We jump to wake people up only if
* the semaphore was negative (== somebody was waiting on it).
*/
static inline void up(struct semaphore * sem)
{
unsigned long flags;
spin_lock_irqsave(&sem->sentry, flags);
if (sem->count < 0) {
__up(sem);
} else {
sem->count++;
}
spin_unlock_irqrestore(&sem->sentry, flags);
}
#endif /* _ASM_PARISC_SEMAPHORE_H */
#include <linux/semaphore.h>
include/asm-powerpc/semaphore.h
View file @ 64ac24e7
#ifndef _ASM_POWERPC_SEMAPHORE_H
#define _ASM_POWERPC_SEMAPHORE_H
/*
* Remove spinlock-based RW semaphores; RW semaphore definitions are
* now in rwsem.h and we use the generic lib/rwsem.c implementation.
* Rework semaphores to use atomic_dec_if_positive.
* -- Paul Mackerras (paulus@samba.org)
*/
#ifdef __KERNEL__
#include <asm/atomic.h>
#include <asm/system.h>
#include <linux/wait.h>
#include <linux/rwsem.h>
struct semaphore {
/*
* Note that any negative value of count is equivalent to 0,
* but additionally indicates that some process(es) might be
* sleeping on `wait'.
*/
atomic_t count;
wait_queue_head_t wait;
};
#define __SEMAPHORE_INITIALIZER(name, n) \
{ \
.count = ATOMIC_INIT(n), \
.wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \
}
#define __DECLARE_SEMAPHORE_GENERIC(name, count) \
struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name, 1)
static inline void sema_init (struct semaphore *sem, int val)
{
atomic_set(&sem->count, val);
init_waitqueue_head(&sem->wait);
}
static inline void init_MUTEX (struct semaphore *sem)
{
sema_init(sem, 1);
}
static inline void init_MUTEX_LOCKED (struct semaphore *sem)
{
sema_init(sem, 0);
}
extern void __down(struct semaphore * sem);
extern int __down_interruptible(struct semaphore * sem);
extern void __up(struct semaphore * sem);
static inline void down(struct semaphore * sem)
{
might_sleep();
/*
* Try to get the semaphore, take the slow path if we fail.
*/
if (unlikely(atomic_dec_return(&sem->count) < 0))
__down(sem);
}
static inline int down_interruptible(struct semaphore * sem)
{
int ret = 0;
might_sleep();
if (unlikely(atomic_dec_return(&sem->count) < 0))
ret = __down_interruptible(sem);
return ret;
}
static inline int down_trylock(struct semaphore * sem)
{
return atomic_dec_if_positive(&sem->count) < 0;
}
static inline void up(struct semaphore * sem)
{
if (unlikely(atomic_inc_return(&sem->count) <= 0))
__up(sem);
}
#endif /* __KERNEL__ */
#endif /* _ASM_POWERPC_SEMAPHORE_H */
#include <linux/semaphore.h>
include/asm-s390/semaphore.h
View file @ 64ac24e7
/*
* include/asm-s390/semaphore.h
*
* S390 version
* Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
*
* Derived from "include/asm-i386/semaphore.h"
* (C) Copyright 1996 Linus Torvalds
*/
#ifndef _S390_SEMAPHORE_H
#define _S390_SEMAPHORE_H
#include <asm/system.h>
#include <asm/atomic.h>
#include <linux/wait.h>
#include <linux/rwsem.h>
struct semaphore {
/*
* Note that any negative value of count is equivalent to 0,
* but additionally indicates that some process(es) might be
* sleeping on `wait'.
*/
atomic_t count;
wait_queue_head_t wait;
};
#define __SEMAPHORE_INITIALIZER(name,count) \
{ ATOMIC_INIT(count), __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) }
#define __DECLARE_SEMAPHORE_GENERIC(name,count) \
struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
static inline void sema_init (struct semaphore *sem, int val)
{
atomic_set(&sem->count, val);
init_waitqueue_head(&sem->wait);
}
static inline void init_MUTEX (struct semaphore *sem)
{
sema_init(sem, 1);
}
static inline void init_MUTEX_LOCKED (struct semaphore *sem)
{
sema_init(sem, 0);
}
asmlinkage void __down(struct semaphore * sem);
asmlinkage int __down_interruptible(struct semaphore * sem);
asmlinkage int __down_trylock(struct semaphore * sem);
asmlinkage void __up(struct semaphore * sem);
static inline void down(struct semaphore * sem)
{
might_sleep();
if (atomic_dec_return(&sem->count) < 0)
__down(sem);
}
static inline int down_interruptible(struct semaphore * sem)
{
int ret = 0;
might_sleep();
if (atomic_dec_return(&sem->count) < 0)
ret = __down_interruptible(sem);
return ret;
}
static inline int down_trylock(struct semaphore * sem)
{
int old_val, new_val;
/*
* This inline assembly atomically implements the equivalent
* to the following C code:
* old_val = sem->count.counter;
* if ((new_val = old_val) > 0)
* sem->count.counter = --new_val;
* In the ppc code this is called atomic_dec_if_positive.
*/
asm volatile(
" l %0,0(%3)\n"
"0: ltr %1,%0\n"
" jle 1f\n"
" ahi %1,-1\n"
" cs %0,%1,0(%3)\n"
" jl 0b\n"
"1:"
: "=&d" (old_val), "=&d" (new_val), "=m" (sem->count.counter)
: "a" (&sem->count.counter), "m" (sem->count.counter)
: "cc", "memory");
return old_val <= 0;
}
static inline void up(struct semaphore * sem)
{
if (atomic_inc_return(&sem->count) <= 0)
__up(sem);
}
#endif
#include <linux/semaphore.h>
include/asm-sh/semaphore-helper.h deleted 100644 → 0
View file @ e48b3dee
#ifndef __ASM_SH_SEMAPHORE_HELPER_H
#define __ASM_SH_SEMAPHORE_HELPER_H
/*
* SMP- and interrupt-safe semaphores helper functions.
*
* (C) Copyright 1996 Linus Torvalds
* (C) Copyright 1999 Andrea Arcangeli
*/
/*
* These two _must_ execute atomically wrt each other.
*
* This is trivially done with load_locked/store_cond,
* which we have. Let the rest of the losers suck eggs.
*/
static __inline__ void wake_one_more(struct semaphore * sem)
{
atomic_inc((atomic_t *)&sem->sleepers);
}
static __inline__ int waking_non_zero(struct semaphore *sem)
{
unsigned long flags;
int ret = 0;
spin_lock_irqsave(&semaphore_wake_lock, flags);
if (sem->sleepers > 0) {
sem->sleepers--;
ret = 1;
}
spin_unlock_irqrestore(&semaphore_wake_lock, flags);
return ret;
}
/*
* waking_non_zero_interruptible:
* 1 got the lock
* 0 go to sleep
* -EINTR interrupted
*
* We must undo the sem->count down_interruptible() increment while we are
* protected by the spinlock in order to make atomic this atomic_inc() with the
* atomic_read() in wake_one_more(), otherwise we can race. -arca
*/
static __inline__ int waking_non_zero_interruptible(struct semaphore *sem,
struct task_struct *tsk)
{
unsigned long flags;
int ret = 0;
spin_lock_irqsave(&semaphore_wake_lock, flags);
if (sem->sleepers > 0) {
sem->sleepers--;
ret = 1;
} else if (signal_pending(tsk)) {
atomic_inc(&sem->count);
ret = -EINTR;
}
spin_unlock_irqrestore(&semaphore_wake_lock, flags);
return ret;
}
/*
* waking_non_zero_trylock:
* 1 failed to lock
* 0 got the lock
*
* We must undo the sem->count down_trylock() increment while we are
* protected by the spinlock in order to make atomic this atomic_inc() with the
* atomic_read() in wake_one_more(), otherwise we can race. -arca
*/
static __inline__ int waking_non_zero_trylock(struct semaphore *sem)
{
unsigned long flags;
int ret = 1;
spin_lock_irqsave(&semaphore_wake_lock, flags);
if (sem->sleepers <= 0)
atomic_inc(&sem->count);
else {
sem->sleepers--;
ret = 0;
}
spin_unlock_irqrestore(&semaphore_wake_lock, flags);
return ret;
}
#endif /* __ASM_SH_SEMAPHORE_HELPER_H */
include/asm-sh/semaphore.h
View file @ 64ac24e7
#ifndef __ASM_SH_SEMAPHORE_H
#define __ASM_SH_SEMAPHORE_H
#include <linux/linkage.h>
#ifdef __KERNEL__
/*
* SMP- and interrupt-safe semaphores.
*
* (C) Copyright 1996 Linus Torvalds
*
* SuperH verison by Niibe Yutaka
* (Currently no asm implementation but generic C code...)
*/
#include <linux/spinlock.h>
#include <linux/rwsem.h>
#include <linux/wait.h>
#include <asm/system.h>
#include <asm/atomic.h>
struct semaphore {
atomic_t count;
int sleepers;
wait_queue_head_t wait;
};
#define __SEMAPHORE_INITIALIZER(name, n) \
{ \
.count = ATOMIC_INIT(n), \
.sleepers = 0, \
.wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \
}
#define __DECLARE_SEMAPHORE_GENERIC(name,count) \
struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
static inline void sema_init (struct semaphore *sem, int val)
{
/*
* *sem = (struct semaphore)__SEMAPHORE_INITIALIZER((*sem),val);
*
* i'd rather use the more flexible initialization above, but sadly
* GCC 2.7.2.3 emits a bogus warning. EGCS doesn't. Oh well.
*/
atomic_set(&sem->count, val);
sem->sleepers = 0;
init_waitqueue_head(&sem->wait);
}
static inline void init_MUTEX (struct semaphore *sem)
{
sema_init(sem, 1);
}
static inline void init_MUTEX_LOCKED (struct semaphore *sem)
{
sema_init(sem, 0);
}
#if 0
asmlinkage void __down_failed(void /* special register calling convention */);
asmlinkage int __down_failed_interruptible(void /* params in registers */);
asmlinkage int __down_failed_trylock(void /* params in registers */);
asmlinkage void __up_wakeup(void /* special register calling convention */);
#endif
asmlinkage void __down(struct semaphore * sem);
asmlinkage int __down_interruptible(struct semaphore * sem);
asmlinkage int __down_trylock(struct semaphore * sem);
asmlinkage void __up(struct semaphore * sem);
extern spinlock_t semaphore_wake_lock;
static inline void down(struct semaphore * sem)
{
might_sleep();
if (atomic_dec_return(&sem->count) < 0)
__down(sem);
}
static inline int down_interruptible(struct semaphore * sem)
{
int ret = 0;
might_sleep();
if (atomic_dec_return(&sem->count) < 0)
ret = __down_interruptible(sem);
return ret;
}
static inline int down_trylock(struct semaphore * sem)
{
int ret = 0;
if (atomic_dec_return(&sem->count) < 0)
ret = __down_trylock(sem);
return ret;
}
/*
* Note! This is subtle. We jump to wake people up only if
* the semaphore was negative (== somebody was waiting on it).
*/
static inline void up(struct semaphore * sem)
{
if (atomic_inc_return(&sem->count) <= 0)
__up(sem);
}
#endif
#endif /* __ASM_SH_SEMAPHORE_H */
#include <linux/semaphore.h>
include/asm-sparc/semaphore.h
View file @ 64ac24e7
#ifndef _SPARC_SEMAPHORE_H
#define _SPARC_SEMAPHORE_H
/* Dinky, good for nothing, just barely irq safe, Sparc semaphores. */
#ifdef __KERNEL__
#include <asm/atomic.h>
#include <linux/wait.h>
#include <linux/rwsem.h>
struct semaphore {
atomic24_t count;
int sleepers;
wait_queue_head_t wait;
};
#define __SEMAPHORE_INITIALIZER(name, n) \
{ \
.count = ATOMIC24_INIT(n), \
.sleepers = 0, \
.wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \
}
#define __DECLARE_SEMAPHORE_GENERIC(name,count) \
struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
static inline void sema_init (struct semaphore *sem, int val)
{
atomic24_set(&sem->count, val);
sem->sleepers = 0;
init_waitqueue_head(&sem->wait);
}
static inline void init_MUTEX (struct semaphore *sem)
{
sema_init(sem, 1);
}
static inline void init_MUTEX_LOCKED (struct semaphore *sem)
{
sema_init(sem, 0);
}
extern void __down(struct semaphore * sem);
extern int __down_interruptible(struct semaphore * sem);
extern int __down_trylock(struct semaphore * sem);
extern void __up(struct semaphore * sem);
static inline void down(struct semaphore * sem)
{
register volatile int *ptr asm("g1");
register int increment asm("g2");
might_sleep();
ptr = &(sem->count.counter);
increment = 1;
__asm__ __volatile__(
"mov %%o7, %%g4\n\t"
"call ___atomic24_sub\n\t"
" add %%o7, 8, %%o7\n\t"
"tst %%g2\n\t"
"bl 2f\n\t"
" nop\n"
"1:\n\t"
".subsection 2\n"
"2:\n\t"
"save %%sp, -64, %%sp\n\t"
"mov %%g1, %%l1\n\t"
"mov %%g5, %%l5\n\t"
"call %3\n\t"
" mov %%g1, %%o0\n\t"
"mov %%l1, %%g1\n\t"
"ba 1b\n\t"
" restore %%l5, %%g0, %%g5\n\t"
".previous\n"
: "=&r" (increment)
: "0" (increment), "r" (ptr), "i" (__down)
: "g3", "g4", "g7", "memory", "cc");
}
static inline int down_interruptible(struct semaphore * sem)
{
register volatile int *ptr asm("g1");
register int increment asm("g2");
might_sleep();
ptr = &(sem->count.counter);
increment = 1;
__asm__ __volatile__(
"mov %%o7, %%g4\n\t"
"call ___atomic24_sub\n\t"
" add %%o7, 8, %%o7\n\t"
"tst %%g2\n\t"
"bl 2f\n\t"
" clr %%g2\n"
"1:\n\t"
".subsection 2\n"
"2:\n\t"
"save %%sp, -64, %%sp\n\t"
"mov %%g1, %%l1\n\t"
"mov %%g5, %%l5\n\t"
"call %3\n\t"
" mov %%g1, %%o0\n\t"
"mov %%l1, %%g1\n\t"
"mov %%l5, %%g5\n\t"
"ba 1b\n\t"
" restore %%o0, %%g0, %%g2\n\t"
".previous\n"
: "=&r" (increment)
: "0" (increment), "r" (ptr), "i" (__down_interruptible)
: "g3", "g4", "g7", "memory", "cc");
return increment;
}
static inline int down_trylock(struct semaphore * sem)
{
register volatile int *ptr asm("g1");
register int increment asm("g2");
ptr = &(sem->count.counter);
increment = 1;
__asm__ __volatile__(
"mov %%o7, %%g4\n\t"
"call ___atomic24_sub\n\t"
" add %%o7, 8, %%o7\n\t"
"tst %%g2\n\t"
"bl 2f\n\t"
" clr %%g2\n"
"1:\n\t"
".subsection 2\n"
"2:\n\t"
"save %%sp, -64, %%sp\n\t"
"mov %%g1, %%l1\n\t"
"mov %%g5, %%l5\n\t"
"call %3\n\t"
" mov %%g1, %%o0\n\t"
"mov %%l1, %%g1\n\t"
"mov %%l5, %%g5\n\t"
"ba 1b\n\t"
" restore %%o0, %%g0, %%g2\n\t"
".previous\n"
: "=&r" (increment)
: "0" (increment), "r" (ptr), "i" (__down_trylock)
: "g3", "g4", "g7", "memory", "cc");
return increment;
}
static inline void up(struct semaphore * sem)
{
register volatile int *ptr asm("g1");
register int increment asm("g2");
ptr = &(sem->count.counter);
increment = 1;
__asm__ __volatile__(
"mov %%o7, %%g4\n\t"
"call ___atomic24_add\n\t"
" add %%o7, 8, %%o7\n\t"
"tst %%g2\n\t"
"ble 2f\n\t"
" nop\n"
"1:\n\t"
".subsection 2\n"
"2:\n\t"
"save %%sp, -64, %%sp\n\t"
"mov %%g1, %%l1\n\t"
"mov %%g5, %%l5\n\t"
"call %3\n\t"
" mov %%g1, %%o0\n\t"
"mov %%l1, %%g1\n\t"
"ba 1b\n\t"
" restore %%l5, %%g0, %%g5\n\t"
".previous\n"
: "=&r" (increment)
: "0" (increment), "r" (ptr), "i" (__up)
: "g3", "g4", "g7", "memory", "cc");
}
#endif /* __KERNEL__ */
#endif /* !(_SPARC_SEMAPHORE_H) */
#include <linux/semaphore.h>
include/asm-sparc64/semaphore.h
View file @ 64ac24e7
#ifndef _SPARC64_SEMAPHORE_H
#define _SPARC64_SEMAPHORE_H
/* These are actually reasonable on the V9.
*
* See asm-ppc/semaphore.h for implementation commentary,
* only sparc64 specific issues are commented here.
*/
#ifdef __KERNEL__
#include <asm/atomic.h>
#include <asm/system.h>
#include <linux/wait.h>
#include <linux/rwsem.h>
struct semaphore {
atomic_t count;
wait_queue_head_t wait;
};
#define __SEMAPHORE_INITIALIZER(name, count) \
{ ATOMIC_INIT(count), \
__WAIT_QUEUE_HEAD_INITIALIZER((name).wait) }
#define __DECLARE_SEMAPHORE_GENERIC(name, count) \
struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name, 1)
static inline void sema_init (struct semaphore *sem, int val)
{
atomic_set(&sem->count, val);
init_waitqueue_head(&sem->wait);
}
static inline void init_MUTEX (struct semaphore *sem)
{
sema_init(sem, 1);
}
static inline void init_MUTEX_LOCKED (struct semaphore *sem)
{
sema_init(sem, 0);
}
extern void up(struct semaphore *sem);
extern void down(struct semaphore *sem);
extern int down_trylock(struct semaphore *sem);
extern int down_interruptible(struct semaphore *sem);
#endif /* __KERNEL__ */
#endif /* !(_SPARC64_SEMAPHORE_H) */
#include <linux/semaphore.h>
include/asm-um/semaphore.h
View file @ 64ac24e7
#ifndef __UM_SEMAPHORE_H
#define __UM_SEMAPHORE_H
#include "asm/arch/semaphore.h"
#endif
#include <linux/semaphore.h>
include/asm-v850/semaphore.h
View file @ 64ac24e7
#ifndef __V850_SEMAPHORE_H__
#define __V850_SEMAPHORE_H__
#include <linux/linkage.h>
#include <linux/spinlock.h>
#include <linux/wait.h>
#include <linux/rwsem.h>
#include <asm/atomic.h>
struct semaphore {
atomic_t count;
int sleepers;
wait_queue_head_t wait;
};
#define __SEMAPHORE_INITIALIZER(name,count) \
{ ATOMIC_INIT (count), 0, \
__WAIT_QUEUE_HEAD_INITIALIZER ((name).wait) }
#define __DECLARE_SEMAPHORE_GENERIC(name,count) \
struct semaphore name = __SEMAPHORE_INITIALIZER (name,count)
#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC (name,1)
static inline void sema_init (struct semaphore *sem, int val)
{
*sem = (struct semaphore)__SEMAPHORE_INITIALIZER((*sem),val);
}
static inline void init_MUTEX (struct semaphore *sem)
{
sema_init (sem, 1);
}
static inline void init_MUTEX_LOCKED (struct semaphore *sem)
{
sema_init (sem, 0);
}
/*
* special register calling convention
*/
asmlinkage void __down_failed (void);
asmlinkage int __down_interruptible_failed (void);
asmlinkage int __down_trylock_failed (void);
asmlinkage void __up_wakeup (void);
extern void __down (struct semaphore * sem);
extern int __down_interruptible (struct semaphore * sem);
extern int __down_trylock (struct semaphore * sem);
extern void __up (struct semaphore * sem);
static inline void down (struct semaphore * sem)
{
might_sleep();
if (atomic_dec_return (&sem->count) < 0)
__down (sem);
}
static inline int down_interruptible (struct semaphore * sem)
{
int ret = 0;
might_sleep();
if (atomic_dec_return (&sem->count) < 0)
ret = __down_interruptible (sem);
return ret;
}
static inline int down_trylock (struct semaphore *sem)
{
int ret = 0;
if (atomic_dec_return (&sem->count) < 0)
ret = __down_trylock (sem);
return ret;
}
static inline void up (struct semaphore * sem)
{
if (atomic_inc_return (&sem->count) <= 0)
__up (sem);
}
#endif /* __V850_SEMAPHORE_H__ */
#include <linux/semaphore.h>
include/asm-x86/semaphore.h
View file @ 64ac24e7
#ifdef CONFIG_X86_32
# include "semaphore_32.h"
#else
# include "semaphore_64.h"
#endif
#include <linux/semaphore.h>
include/asm-x86/semaphore_32.h deleted 100644 → 0
View file @ e48b3dee
#ifndef _I386_SEMAPHORE_H
#define _I386_SEMAPHORE_H
#include <linux/linkage.h>
#ifdef __KERNEL__
/*
* SMP- and interrupt-safe semaphores..
*
* (C) Copyright 1996 Linus Torvalds
*
* Modified 1996-12-23 by Dave Grothe <dave@gcom.com> to fix bugs in
* the original code and to make semaphore waits
* interruptible so that processes waiting on
* semaphores can be killed.
* Modified 1999-02-14 by Andrea Arcangeli, split the sched.c helper
* functions in asm/sempahore-helper.h while fixing a
* potential and subtle race discovered by Ulrich Schmid
* in down_interruptible(). Since I started to play here I
* also implemented the `trylock' semaphore operation.
* 1999-07-02 Artur Skawina <skawina@geocities.com>
* Optimized "0(ecx)" -> "(ecx)" (the assembler does not
* do this). Changed calling sequences from push/jmp to
* traditional call/ret.
* Modified 2001-01-01 Andreas Franck <afranck@gmx.de>
* Some hacks to ensure compatibility with recent
* GCC snapshots, to avoid stack corruption when compiling
* with -fomit-frame-pointer. It's not sure if this will
* be fixed in GCC, as our previous implementation was a
* bit dubious.
*
* If you would like to see an analysis of this implementation, please
* ftp to gcom.com and download the file
* /pub/linux/src/semaphore/semaphore-2.0.24.tar.gz.
*
*/
#include <asm/system.h>
#include <asm/atomic.h>
#include <linux/wait.h>
#include <linux/rwsem.h>
struct semaphore {
atomic_t count;
int sleepers;
wait_queue_head_t wait;
};
#define __SEMAPHORE_INITIALIZER(name, n) \
{ \
.count = ATOMIC_INIT(n), \
.sleepers = 0, \
.wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \
}
#define __DECLARE_SEMAPHORE_GENERIC(name,count) \
struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
static inline void sema_init (struct semaphore *sem, int val)
{
/*
* *sem = (struct semaphore)__SEMAPHORE_INITIALIZER((*sem),val);
*
* i'd rather use the more flexible initialization above, but sadly
* GCC 2.7.2.3 emits a bogus warning. EGCS doesn't. Oh well.
*/
atomic_set(&sem->count, val);
sem->sleepers = 0;
init_waitqueue_head(&sem->wait);
}
static inline void init_MUTEX (struct semaphore *sem)
{
sema_init(sem, 1);
}
static inline void init_MUTEX_LOCKED (struct semaphore *sem)
{
sema_init(sem, 0);
}
extern asmregparm void __down_failed(atomic_t *count_ptr);
extern asmregparm int __down_failed_interruptible(atomic_t *count_ptr);
extern asmregparm int __down_failed_trylock(atomic_t *count_ptr);
extern asmregparm void __up_wakeup(atomic_t *count_ptr);
/*
* This is ugly, but we want the default case to fall through.
* "__down_failed" is a special asm handler that calls the C
* routine that actually waits. See arch/i386/kernel/semaphore.c
*/
static inline void down(struct semaphore * sem)
{
might_sleep();
__asm__ __volatile__(
"# atomic down operation\n\t"
LOCK_PREFIX "decl %0\n\t" /* --sem->count */
"jns 2f\n"
"\tlea %0,%%eax\n\t"
"call __down_failed\n"
"2:"
:"+m" (sem->count)
:
:"memory","ax");
}
/*
* Interruptible try to acquire a semaphore. If we obtained
* it, return zero. If we were interrupted, returns -EINTR
*/
static inline int down_interruptible(struct semaphore * sem)
{
int result;
might_sleep();
__asm__ __volatile__(
"# atomic interruptible down operation\n\t"
"xorl %0,%0\n\t"
LOCK_PREFIX "decl %1\n\t" /* --sem->count */
"jns 2f\n\t"
"lea %1,%%eax\n\t"
"call __down_failed_interruptible\n"
"2:"
:"=&a" (result), "+m" (sem->count)
:
:"memory");
return result;
}
/*
* Non-blockingly attempt to down() a semaphore.
* Returns zero if we acquired it
*/
static inline int down_trylock(struct semaphore * sem)
{
int result;
__asm__ __volatile__(
"# atomic interruptible down operation\n\t"
"xorl %0,%0\n\t"
LOCK_PREFIX "decl %1\n\t" /* --sem->count */
"jns 2f\n\t"
"lea %1,%%eax\n\t"
"call __down_failed_trylock\n\t"
"2:\n"
:"=&a" (result), "+m" (sem->count)
:
:"memory");
return result;
}
/*
* Note! This is subtle. We jump to wake people up only if
* the semaphore was negative (== somebody was waiting on it).
*/
static inline void up(struct semaphore * sem)
{
__asm__ __volatile__(
"# atomic up operation\n\t"
LOCK_PREFIX "incl %0\n\t" /* ++sem->count */
"jg 1f\n\t"
"lea %0,%%eax\n\t"
"call __up_wakeup\n"
"1:"
:"+m" (sem->count)
:
:"memory","ax");
}
#endif
#endif
include/asm-x86/semaphore_64.h deleted 100644 → 0
View file @ e48b3dee
#ifndef _X86_64_SEMAPHORE_H
#define _X86_64_SEMAPHORE_H
#include <linux/linkage.h>
#ifdef __KERNEL__
/*
* SMP- and interrupt-safe semaphores..
*
* (C) Copyright 1996 Linus Torvalds
*
* Modified 1996-12-23 by Dave Grothe <dave@gcom.com> to fix bugs in
* the original code and to make semaphore waits
* interruptible so that processes waiting on
* semaphores can be killed.
* Modified 1999-02-14 by Andrea Arcangeli, split the sched.c helper
* functions in asm/sempahore-helper.h while fixing a
* potential and subtle race discovered by Ulrich Schmid
* in down_interruptible(). Since I started to play here I
* also implemented the `trylock' semaphore operation.
* 1999-07-02 Artur Skawina <skawina@geocities.com>
* Optimized "0(ecx)" -> "(ecx)" (the assembler does not
* do this). Changed calling sequences from push/jmp to
* traditional call/ret.
* Modified 2001-01-01 Andreas Franck <afranck@gmx.de>
* Some hacks to ensure compatibility with recent
* GCC snapshots, to avoid stack corruption when compiling
* with -fomit-frame-pointer. It's not sure if this will
* be fixed in GCC, as our previous implementation was a
* bit dubious.
*
* If you would like to see an analysis of this implementation, please
* ftp to gcom.com and download the file
* /pub/linux/src/semaphore/semaphore-2.0.24.tar.gz.
*
*/
#include <asm/system.h>
#include <asm/atomic.h>
#include <asm/rwlock.h>
#include <linux/wait.h>
#include <linux/rwsem.h>
#include <linux/stringify.h>
struct semaphore {
atomic_t count;
int sleepers;
wait_queue_head_t wait;
};
#define __SEMAPHORE_INITIALIZER(name, n) \
{ \
.count = ATOMIC_INIT(n), \
.sleepers = 0, \
.wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \
}
#define __DECLARE_SEMAPHORE_GENERIC(name,count) \
struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
static inline void sema_init (struct semaphore *sem, int val)
{
/*
* *sem = (struct semaphore)__SEMAPHORE_INITIALIZER((*sem),val);
*
* i'd rather use the more flexible initialization above, but sadly
* GCC 2.7.2.3 emits a bogus warning. EGCS doesn't. Oh well.
*/
atomic_set(&sem->count, val);
sem->sleepers = 0;
init_waitqueue_head(&sem->wait);
}
static inline void init_MUTEX (struct semaphore *sem)
{
sema_init(sem, 1);
}
static inline void init_MUTEX_LOCKED (struct semaphore *sem)
{
sema_init(sem, 0);
}
asmlinkage void __down_failed(void /* special register calling convention */);
asmlinkage int __down_failed_interruptible(void /* params in registers */);
asmlinkage int __down_failed_trylock(void /* params in registers */);
asmlinkage void __up_wakeup(void /* special register calling convention */);
asmlinkage void __down(struct semaphore * sem);
asmlinkage int __down_interruptible(struct semaphore * sem);
asmlinkage int __down_trylock(struct semaphore * sem);
asmlinkage void __up(struct semaphore * sem);
/*
* This is ugly, but we want the default case to fall through.
* "__down_failed" is a special asm handler that calls the C
* routine that actually waits. See arch/x86_64/kernel/semaphore.c
*/
static inline void down(struct semaphore * sem)
{
might_sleep();
__asm__ __volatile__(
"# atomic down operation\n\t"
LOCK_PREFIX "decl %0\n\t" /* --sem->count */
"jns 1f\n\t"
"call __down_failed\n"
"1:"
:"=m" (sem->count)
:"D" (sem)
:"memory");
}
/*
* Interruptible try to acquire a semaphore. If we obtained
* it, return zero. If we were interrupted, returns -EINTR
*/
static inline int down_interruptible(struct semaphore * sem)
{
int result;
might_sleep();
__asm__ __volatile__(
"# atomic interruptible down operation\n\t"
"xorl %0,%0\n\t"
LOCK_PREFIX "decl %1\n\t" /* --sem->count */
"jns 2f\n\t"
"call __down_failed_interruptible\n"
"2:\n"
:"=&a" (result), "=m" (sem->count)
:"D" (sem)
:"memory");
return result;
}
/*
* Non-blockingly attempt to down() a semaphore.
* Returns zero if we acquired it
*/
static inline int down_trylock(struct semaphore * sem)
{
int result;
__asm__ __volatile__(
"# atomic interruptible down operation\n\t"
"xorl %0,%0\n\t"
LOCK_PREFIX "decl %1\n\t" /* --sem->count */
"jns 2f\n\t"
"call __down_failed_trylock\n\t"
"2:\n"
:"=&a" (result), "=m" (sem->count)
:"D" (sem)
:"memory","cc");
return result;
}
/*
* Note! This is subtle. We jump to wake people up only if
* the semaphore was negative (== somebody was waiting on it).
* The default case (no contention) will result in NO
* jumps for both down() and up().
*/
static inline void up(struct semaphore * sem)
{
__asm__ __volatile__(
"# atomic up operation\n\t"
LOCK_PREFIX "incl %0\n\t" /* ++sem->count */
"jg 1f\n\t"
"call __up_wakeup\n"
"1:"
:"=m" (sem->count)
:"D" (sem)
:"memory");
}
#endif /* __KERNEL__ */
#endif
include/asm-xtensa/semaphore.h
View file @ 64ac24e7
/*
* linux/include/asm-xtensa/semaphore.h
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 2001 - 2005 Tensilica Inc.
*/
#ifndef _XTENSA_SEMAPHORE_H
#define _XTENSA_SEMAPHORE_H
#include <asm/atomic.h>
#include <asm/system.h>
#include <linux/wait.h>
#include <linux/rwsem.h>
struct semaphore {
atomic_t count;
int sleepers;
wait_queue_head_t wait;
};
#define __SEMAPHORE_INITIALIZER(name,n) \
{ \
.count = ATOMIC_INIT(n), \
.sleepers = 0, \
.wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \
}
#define __DECLARE_SEMAPHORE_GENERIC(name,count) \
struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
static inline void sema_init (struct semaphore *sem, int val)
{
atomic_set(&sem->count, val);
sem->sleepers = 0;
init_waitqueue_head(&sem->wait);
}
static inline void init_MUTEX (struct semaphore *sem)
{
sema_init(sem, 1);
}
static inline void init_MUTEX_LOCKED (struct semaphore *sem)
{
sema_init(sem, 0);
}
asmlinkage void __down(struct semaphore * sem);
asmlinkage int __down_interruptible(struct semaphore * sem);
asmlinkage int __down_trylock(struct semaphore * sem);
asmlinkage void __up(struct semaphore * sem);
extern spinlock_t semaphore_wake_lock;
static inline void down(struct semaphore * sem)
{
might_sleep();
if (atomic_sub_return(1, &sem->count) < 0)
__down(sem);
}
static inline int down_interruptible(struct semaphore * sem)
{
int ret = 0;
might_sleep();
if (atomic_sub_return(1, &sem->count) < 0)
ret = __down_interruptible(sem);
return ret;
}
static inline int down_trylock(struct semaphore * sem)
{
int ret = 0;
if (atomic_sub_return(1, &sem->count) < 0)
ret = __down_trylock(sem);
return ret;
}
/*
* Note! This is subtle. We jump to wake people up only if
* the semaphore was negative (== somebody was waiting on it).
*/
static inline void up(struct semaphore * sem)
{
if (atomic_add_return(1, &sem->count) <= 0)
__up(sem);
}
#endif /* _XTENSA_SEMAPHORE_H */
#include <linux/semaphore.h>
include/linux/semaphore.h 0 → 100644
View file @ 64ac24e7
/*
* Copyright (c) 2008 Intel Corporation
* Author: Matthew Wilcox <willy@linux.intel.com>
*
* Distributed under the terms of the GNU GPL, version 2
*
* Counting semaphores allow up to <n> tasks to acquire the semaphore
* simultaneously.
*/
#ifndef __LINUX_SEMAPHORE_H
#define __LINUX_SEMAPHORE_H
#include <linux/list.h>
#include <linux/spinlock.h>
/*
* The spinlock controls access to the other members of the semaphore.
* 'count' is decremented by every task which calls down*() and incremented
* by every call to up(). Thus, if it is positive, it indicates how many
* more tasks may acquire the lock. If it is negative, it indicates how
* many tasks are waiting for the lock. Tasks waiting for the lock are
* kept on the wait_list.
*/
struct semaphore {
spinlock_t lock;
int count;
struct list_head wait_list;
};
#define __SEMAPHORE_INITIALIZER(name, n) \
{ \
.lock = __SPIN_LOCK_UNLOCKED((name).lock), \
.count = n, \
.wait_list = LIST_HEAD_INIT((name).wait_list), \
}
#define __DECLARE_SEMAPHORE_GENERIC(name, count) \
struct semaphore name = __SEMAPHORE_INITIALIZER(name, count)
#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name, 1)
static inline void sema_init(struct semaphore *sem, int val)
{
static struct lock_class_key __key;
*sem = (struct semaphore) __SEMAPHORE_INITIALIZER(*sem, val);
lockdep_init_map(&sem->lock.dep_map, "semaphore->lock", &__key, 0);
}
#define init_MUTEX(sem) sema_init(sem, 1)
#define init_MUTEX_LOCKED(sem) sema_init(sem, 0)
/*
* Attempt to acquire the semaphore. If another task is already holding the
* semaphore, sleep until the semaphore is released.
*/
extern void down(struct semaphore *sem);
/*
* As down(), except the sleep may be interrupted by a signal. If it is,
* this function will return -EINTR.
*/
extern int __must_check down_interruptible(struct semaphore *sem);
/*
* As down(), except this function will not sleep. It will return 0 if it
* acquired the semaphore and 1 if the semaphore was contended. This
* function may be called from any context, including interrupt and softirq.
*/
extern int __must_check down_trylock(struct semaphore *sem);
/*
* Release the semaphore. Unlike mutexes, up() may be called from any
* context and even by tasks which have never called down().
*/
extern void up(struct semaphore *sem);
#endif /* __LINUX_SEMAPHORE_H */
kernel/Makefile
View file @ 64ac24e7
......@@ -8,7 +8,7 @@ obj-y = sched.o fork.o exec_domain.o panic.o printk.o profile.o \
signal.o sys.o kmod.o workqueue.o pid.o \
rcupdate.o extable.o params.o posix-timers.o \
kthread.o wait.o kfifo.o sys_ni.o posix-cpu-timers.o mutex.o \
hrtimer.o rwsem.o nsproxy.o srcu.o \
hrtimer.o rwsem.o nsproxy.o srcu.o semaphore.o \
notifier.o ksysfs.o pm_qos_params.o
obj-$(CONFIG_SYSCTL) += sysctl_check.o
......
kernel/semaphore.c 0 → 100644
View file @ 64ac24e7
/*
* Copyright (c) 2008 Intel Corporation
* Author: Matthew Wilcox <willy@linux.intel.com>
*
* Distributed under the terms of the GNU GPL, version 2
*/
#include <linux/compiler.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/semaphore.h>
#include <linux/spinlock.h>
/*
* Some notes on the implementation:
*
* down_trylock() and up() can be called from interrupt context.
* So we have to disable interrupts when taking the lock.
*
* The ->count variable, if positive, defines how many more tasks can
* acquire the semaphore. If negative, it represents how many tasks are
* waiting on the semaphore (*). If zero, no tasks are waiting, and no more
* tasks can acquire the semaphore.
*
* (*) Except for the window between one task calling up() and the task
* sleeping in a __down_common() waking up. In order to avoid a third task
* coming in and stealing the second task's wakeup, we leave the ->count
* negative. If we have a more complex situation, the ->count may become
* zero or negative (eg a semaphore with count = 2, three tasks attempt to
* acquire it, one sleeps, two finish and call up(), the second task to call
* up() notices that the list is empty and just increments count).
*/
static noinline void __down(struct semaphore *sem);
static noinline int __down_interruptible(struct semaphore *sem);
static noinline void __up(struct semaphore *sem);
void down(struct semaphore *sem)
{
unsigned long flags;
spin_lock_irqsave(&sem->lock, flags);
if (unlikely(sem->count-- <= 0))
__down(sem);
spin_unlock_irqrestore(&sem->lock, flags);
}
EXPORT_SYMBOL(down);
int down_interruptible(struct semaphore *sem)
{
unsigned long flags;
int result = 0;
spin_lock_irqsave(&sem->lock, flags);
if (unlikely(sem->count-- <= 0))
result = __down_interruptible(sem);
spin_unlock_irqrestore(&sem->lock, flags);
return result;
}
EXPORT_SYMBOL(down_interruptible);
/**
* down_trylock - try to acquire the semaphore, without waiting
* @sem: the semaphore to be acquired
*
* Try to acquire the semaphore atomically. Returns 0 if the mutex has
* been acquired successfully and 1 if it is contended.
*
* NOTE: This return value is inverted from both spin_trylock and
* mutex_trylock! Be careful about this when converting code.
*
* Unlike mutex_trylock, this function can be used from interrupt context,
* and the semaphore can be released by any task or interrupt.
*/
int down_trylock(struct semaphore *sem)
{
unsigned long flags;
int count;
spin_lock_irqsave(&sem->lock, flags);
count = sem->count - 1;
if (likely(count >= 0))
sem->count = count;
spin_unlock_irqrestore(&sem->lock, flags);
return (count < 0);
}
EXPORT_SYMBOL(down_trylock);
void up(struct semaphore *sem)
{
unsigned long flags;
spin_lock_irqsave(&sem->lock, flags);
if (likely(sem->count >= 0))
sem->count++;
else
__up(sem);
spin_unlock_irqrestore(&sem->lock, flags);
}
EXPORT_SYMBOL(up);
/* Functions for the contended case */
struct semaphore_waiter {
struct list_head list;
struct task_struct *task;
int up;
};
/*
* Wake up a process waiting on a semaphore. We need to call this from both
* __up and __down_common as it's possible to race a task into the semaphore
* if it comes in at just the right time between two tasks calling up() and
* a third task waking up. This function assumes the wait_list is already
* checked for being non-empty.
*/
static noinline void __sched __up_down_common(struct semaphore *sem)
{
struct semaphore_waiter *waiter = list_first_entry(&sem->wait_list,
struct semaphore_waiter, list);
list_del(&waiter->list);
waiter->up = 1;
wake_up_process(waiter->task);
}
/*
* Because this function is inlined, the 'state' parameter will be constant,
* and thus optimised away by the compiler.
*/
static inline int __sched __down_common(struct semaphore *sem, long state)
{
int result = 0;
struct task_struct *task = current;
struct semaphore_waiter waiter;
list_add_tail(&waiter.list, &sem->wait_list);
waiter.task = task;
waiter.up = 0;
for (;;) {
if (state == TASK_INTERRUPTIBLE && signal_pending(task))
goto interrupted;
__set_task_state(task, state);
spin_unlock_irq(&sem->lock);
schedule();
spin_lock_irq(&sem->lock);
if (waiter.up)
goto woken;
}
interrupted:
list_del(&waiter.list);
result = -EINTR;
woken:
/*
* Account for the process which woke us up. For the case where
* we're interrupted, we need to increment the count on our own
* behalf. I don't believe we can hit the case where the
* sem->count hits zero, *and* there's a second task sleeping,
* but it doesn't hurt, that's not a commonly exercised path and
* it's not a performance path either.
*/
if (unlikely((++sem->count >= 0) && !list_empty(&sem->wait_list)))
__up_down_common(sem);
return result;
}
static noinline void __sched __down(struct semaphore *sem)
{
__down_common(sem, TASK_UNINTERRUPTIBLE);
}
static noinline int __sched __down_interruptible(struct semaphore *sem)
{
return __down_common(sem, TASK_INTERRUPTIBLE);
}
static noinline void __sched __up(struct semaphore *sem)
{
if (unlikely(list_empty(&sem->wait_list)))
sem->count++;
else
__up_down_common(sem);
}
lib/Makefile
View file @ 64ac24e7
......@@ -29,7 +29,6 @@ obj-$(CONFIG_DEBUG_LOCKING_API_SELFTESTS) += locking-selftest.o
obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock_debug.o
lib-$(CONFIG_RWSEM_GENERIC_SPINLOCK) += rwsem-spinlock.o
lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem.o
lib-$(CONFIG_SEMAPHORE_SLEEPERS) += semaphore-sleepers.o
lib-$(CONFIG_GENERIC_FIND_NEXT_BIT) += find_next_bit.o
obj-$(CONFIG_GENERIC_HWEIGHT) += hweight.o
obj-$(CONFIG_LOCK_KERNEL) += kernel_lock.o
......
lib/semaphore-sleepers.c deleted 100644 → 0
View file @ e48b3dee
/*
* i386 and x86-64 semaphore implementation.
*
* (C) Copyright 1999 Linus Torvalds
*
* Portions Copyright 1999 Red Hat, Inc.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* rw semaphores implemented November 1999 by Benjamin LaHaise <bcrl@kvack.org>
*/
#include <linux/sched.h>
#include <linux/err.h>
#include <linux/init.h>
#include <asm/semaphore.h>
/*
* Semaphores are implemented using a two-way counter:
* The "count" variable is decremented for each process
* that tries to acquire the semaphore, while the "sleeping"
* variable is a count of such acquires.
*
* Notably, the inline "up()" and "down()" functions can
* efficiently test if they need to do any extra work (up
* needs to do something only if count was negative before
* the increment operation.
*
* "sleeping" and the contention routine ordering is protected
* by the spinlock in the semaphore's waitqueue head.
*
* Note that these functions are only called when there is
* contention on the lock, and as such all this is the
* "non-critical" part of the whole semaphore business. The
* critical part is the inline stuff in <asm/semaphore.h>
* where we want to avoid any extra jumps and calls.
*/
/*
* Logic:
* - only on a boundary condition do we need to care. When we go
* from a negative count to a non-negative, we wake people up.
* - when we go from a non-negative count to a negative do we
* (a) synchronize with the "sleeper" count and (b) make sure
* that we're on the wakeup list before we synchronize so that
* we cannot lose wakeup events.
*/
void __up(struct semaphore *sem)
{
wake_up(&sem->wait);
}
void __sched __down(struct semaphore *sem)
{
struct task_struct *tsk = current;
DECLARE_WAITQUEUE(wait, tsk);
unsigned long flags;
tsk->state = TASK_UNINTERRUPTIBLE;
spin_lock_irqsave(&sem->wait.lock, flags);
add_wait_queue_exclusive_locked(&sem->wait, &wait);
sem->sleepers++;
for (;;) {
int sleepers = sem->sleepers;
/*
* Add "everybody else" into it. They aren't
* playing, because we own the spinlock in
* the wait_queue_head.
*/
if (!atomic_add_negative(sleepers - 1, &sem->count)) {
sem->sleepers = 0;
break;
}
sem->sleepers = 1; /* us - see -1 above */
spin_unlock_irqrestore(&sem->wait.lock, flags);
schedule();
spin_lock_irqsave(&sem->wait.lock, flags);
tsk->state = TASK_UNINTERRUPTIBLE;
}
remove_wait_queue_locked(&sem->wait, &wait);
wake_up_locked(&sem->wait);
spin_unlock_irqrestore(&sem->wait.lock, flags);
tsk->state = TASK_RUNNING;
}
int __sched __down_interruptible(struct semaphore *sem)
{
int retval = 0;
struct task_struct *tsk = current;
DECLARE_WAITQUEUE(wait, tsk);
unsigned long flags;
tsk->state = TASK_INTERRUPTIBLE;
spin_lock_irqsave(&sem->wait.lock, flags);
add_wait_queue_exclusive_locked(&sem->wait, &wait);
sem->sleepers++;
for (;;) {
int sleepers = sem->sleepers;
/*
* With signals pending, this turns into
* the trylock failure case - we won't be
* sleeping, and we* can't get the lock as
* it has contention. Just correct the count
* and exit.
*/
if (signal_pending(current)) {
retval = -EINTR;
sem->sleepers = 0;
atomic_add(sleepers, &sem->count);
break;
}
/*
* Add "everybody else" into it. They aren't
* playing, because we own the spinlock in
* wait_queue_head. The "-1" is because we're
* still hoping to get the semaphore.
*/
if (!atomic_add_negative(sleepers - 1, &sem->count)) {
sem->sleepers = 0;
break;
}
sem->sleepers = 1; /* us - see -1 above */
spin_unlock_irqrestore(&sem->wait.lock, flags);
schedule();
spin_lock_irqsave(&sem->wait.lock, flags);
tsk->state = TASK_INTERRUPTIBLE;
}
remove_wait_queue_locked(&sem->wait, &wait);
wake_up_locked(&sem->wait);
spin_unlock_irqrestore(&sem->wait.lock, flags);
tsk->state = TASK_RUNNING;
return retval;
}
/*
* Trylock failed - make sure we correct for
* having decremented the count.
*
* We could have done the trylock with a
* single "cmpxchg" without failure cases,
* but then it wouldn't work on a 386.
*/
int __down_trylock(struct semaphore *sem)
{
int sleepers;
unsigned long flags;
spin_lock_irqsave(&sem->wait.lock, flags);
sleepers = sem->sleepers + 1;
sem->sleepers = 0;
/*
* Add "everybody else" and us into it. They aren't
* playing, because we own the spinlock in the
* wait_queue_head.
*/
if (!atomic_add_negative(sleepers, &sem->count)) {
wake_up_locked(&sem->wait);
}
spin_unlock_irqrestore(&sem->wait.lock, flags);
return 1;
}
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