Commit 97245d00 authored by Linus Torvalds's avatar Linus Torvalds Committed by Ingo Molnar

x86/entry: Get rid of pt_regs_to_thread_info()

It was a nice optimization while it lasted, but thread_info is moving
and this optimization will no longer work.

Quoting Linus:

    Oh Gods, Andy. That pt_regs_to_thread_info() thing made me want
    to do unspeakable acts on a poor innocent wax figure that looked
    _exactly_ like you.

[ Changelog written by Andy. ]
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarAndy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jann Horn <jann@thejh.net>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/6376aa81c68798cc81631673f52bd91a3e078944.1473801993.git.luto@kernel.orgSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent b9d989c7
...@@ -31,13 +31,6 @@ ...@@ -31,13 +31,6 @@
#define CREATE_TRACE_POINTS #define CREATE_TRACE_POINTS
#include <trace/events/syscalls.h> #include <trace/events/syscalls.h>
static struct thread_info *pt_regs_to_thread_info(struct pt_regs *regs)
{
unsigned long top_of_stack =
(unsigned long)(regs + 1) + TOP_OF_KERNEL_STACK_PADDING;
return (struct thread_info *)(top_of_stack - THREAD_SIZE);
}
#ifdef CONFIG_CONTEXT_TRACKING #ifdef CONFIG_CONTEXT_TRACKING
/* Called on entry from user mode with IRQs off. */ /* Called on entry from user mode with IRQs off. */
__visible inline void enter_from_user_mode(void) __visible inline void enter_from_user_mode(void)
...@@ -71,7 +64,7 @@ static long syscall_trace_enter(struct pt_regs *regs) ...@@ -71,7 +64,7 @@ static long syscall_trace_enter(struct pt_regs *regs)
{ {
u32 arch = in_ia32_syscall() ? AUDIT_ARCH_I386 : AUDIT_ARCH_X86_64; u32 arch = in_ia32_syscall() ? AUDIT_ARCH_I386 : AUDIT_ARCH_X86_64;
struct thread_info *ti = pt_regs_to_thread_info(regs); struct thread_info *ti = current_thread_info();
unsigned long ret = 0; unsigned long ret = 0;
bool emulated = false; bool emulated = false;
u32 work; u32 work;
...@@ -173,18 +166,17 @@ static void exit_to_usermode_loop(struct pt_regs *regs, u32 cached_flags) ...@@ -173,18 +166,17 @@ static void exit_to_usermode_loop(struct pt_regs *regs, u32 cached_flags)
/* Disable IRQs and retry */ /* Disable IRQs and retry */
local_irq_disable(); local_irq_disable();
cached_flags = READ_ONCE(pt_regs_to_thread_info(regs)->flags); cached_flags = READ_ONCE(current_thread_info()->flags);
if (!(cached_flags & EXIT_TO_USERMODE_LOOP_FLAGS)) if (!(cached_flags & EXIT_TO_USERMODE_LOOP_FLAGS))
break; break;
} }
} }
/* Called with IRQs disabled. */ /* Called with IRQs disabled. */
__visible inline void prepare_exit_to_usermode(struct pt_regs *regs) __visible inline void prepare_exit_to_usermode(struct pt_regs *regs)
{ {
struct thread_info *ti = pt_regs_to_thread_info(regs); struct thread_info *ti = current_thread_info();
u32 cached_flags; u32 cached_flags;
if (IS_ENABLED(CONFIG_PROVE_LOCKING) && WARN_ON(!irqs_disabled())) if (IS_ENABLED(CONFIG_PROVE_LOCKING) && WARN_ON(!irqs_disabled()))
...@@ -247,7 +239,7 @@ static void syscall_slow_exit_work(struct pt_regs *regs, u32 cached_flags) ...@@ -247,7 +239,7 @@ static void syscall_slow_exit_work(struct pt_regs *regs, u32 cached_flags)
*/ */
__visible inline void syscall_return_slowpath(struct pt_regs *regs) __visible inline void syscall_return_slowpath(struct pt_regs *regs)
{ {
struct thread_info *ti = pt_regs_to_thread_info(regs); struct thread_info *ti = current_thread_info();
u32 cached_flags = READ_ONCE(ti->flags); u32 cached_flags = READ_ONCE(ti->flags);
CT_WARN_ON(ct_state() != CONTEXT_KERNEL); CT_WARN_ON(ct_state() != CONTEXT_KERNEL);
...@@ -270,7 +262,7 @@ __visible inline void syscall_return_slowpath(struct pt_regs *regs) ...@@ -270,7 +262,7 @@ __visible inline void syscall_return_slowpath(struct pt_regs *regs)
#ifdef CONFIG_X86_64 #ifdef CONFIG_X86_64
__visible void do_syscall_64(struct pt_regs *regs) __visible void do_syscall_64(struct pt_regs *regs)
{ {
struct thread_info *ti = pt_regs_to_thread_info(regs); struct thread_info *ti = current_thread_info();
unsigned long nr = regs->orig_ax; unsigned long nr = regs->orig_ax;
enter_from_user_mode(); enter_from_user_mode();
...@@ -303,7 +295,7 @@ __visible void do_syscall_64(struct pt_regs *regs) ...@@ -303,7 +295,7 @@ __visible void do_syscall_64(struct pt_regs *regs)
*/ */
static __always_inline void do_syscall_32_irqs_on(struct pt_regs *regs) static __always_inline void do_syscall_32_irqs_on(struct pt_regs *regs)
{ {
struct thread_info *ti = pt_regs_to_thread_info(regs); struct thread_info *ti = current_thread_info();
unsigned int nr = (unsigned int)regs->orig_ax; unsigned int nr = (unsigned int)regs->orig_ax;
#ifdef CONFIG_IA32_EMULATION #ifdef CONFIG_IA32_EMULATION
......
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