Commit 3bd95dfb authored by Brian Gerst's avatar Brian Gerst Committed by H. Peter Anvin

x86, 64-bit: Move kernel_thread to C

Prepare for merging with 32-bit.
Signed-off-by: default avatarBrian Gerst <brgerst@gmail.com>
LKML-Reference: <1260380084-3707-2-git-send-email-brgerst@gmail.com>
Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
parent fc380cee
...@@ -1166,63 +1166,20 @@ bad_gs: ...@@ -1166,63 +1166,20 @@ bad_gs:
jmp 2b jmp 2b
.previous .previous
/* ENTRY(kernel_thread_helper)
* Create a kernel thread.
*
* C extern interface:
* extern long kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
*
* asm input arguments:
* rdi: fn, rsi: arg, rdx: flags
*/
ENTRY(kernel_thread)
CFI_STARTPROC
FAKE_STACK_FRAME $child_rip
SAVE_ALL
# rdi: flags, rsi: usp, rdx: will be &pt_regs
movq %rdx,%rdi
orq kernel_thread_flags(%rip),%rdi
movq $-1, %rsi
movq %rsp, %rdx
xorl %r8d,%r8d
xorl %r9d,%r9d
# clone now
call do_fork
movq %rax,RAX(%rsp)
xorl %edi,%edi
/*
* It isn't worth to check for reschedule here,
* so internally to the x86_64 port you can rely on kernel_thread()
* not to reschedule the child before returning, this avoids the need
* of hacks for example to fork off the per-CPU idle tasks.
* [Hopefully no generic code relies on the reschedule -AK]
*/
RESTORE_ALL
UNFAKE_STACK_FRAME
ret
CFI_ENDPROC
END(kernel_thread)
ENTRY(child_rip)
pushq $0 # fake return address pushq $0 # fake return address
CFI_STARTPROC CFI_STARTPROC
/* /*
* Here we are in the child and the registers are set as they were * Here we are in the child and the registers are set as they were
* at kernel_thread() invocation in the parent. * at kernel_thread() invocation in the parent.
*/ */
movq %rdi, %rax call *%rsi
movq %rsi, %rdi
call *%rax
# exit # exit
mov %eax, %edi mov %eax, %edi
call do_exit call do_exit
ud2 # padding for call trace ud2 # padding for call trace
CFI_ENDPROC CFI_ENDPROC
END(child_rip) END(kernel_thread_helper)
/* /*
* execve(). This function needs to use IRET, not SYSRET, to set up all state properly. * execve(). This function needs to use IRET, not SYSRET, to set up all state properly.
......
...@@ -59,8 +59,6 @@ asmlinkage extern void ret_from_fork(void); ...@@ -59,8 +59,6 @@ asmlinkage extern void ret_from_fork(void);
DEFINE_PER_CPU(unsigned long, old_rsp); DEFINE_PER_CPU(unsigned long, old_rsp);
static DEFINE_PER_CPU(unsigned char, is_idle); static DEFINE_PER_CPU(unsigned char, is_idle);
unsigned long kernel_thread_flags = CLONE_VM | CLONE_UNTRACED;
static ATOMIC_NOTIFIER_HEAD(idle_notifier); static ATOMIC_NOTIFIER_HEAD(idle_notifier);
void idle_notifier_register(struct notifier_block *n) void idle_notifier_register(struct notifier_block *n)
...@@ -231,6 +229,35 @@ void show_regs(struct pt_regs *regs) ...@@ -231,6 +229,35 @@ void show_regs(struct pt_regs *regs)
show_trace(NULL, regs, (void *)(regs + 1), regs->bp); show_trace(NULL, regs, (void *)(regs + 1), regs->bp);
} }
/*
* This gets run with %si containing the
* function to call, and %di containing
* the "args".
*/
extern void kernel_thread_helper(void);
/*
* Create a kernel thread
*/
int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
{
struct pt_regs regs;
memset(&regs, 0, sizeof(regs));
regs.si = (unsigned long) fn;
regs.di = (unsigned long) arg;
regs.orig_ax = -1;
regs.ip = (unsigned long) kernel_thread_helper;
regs.cs = __KERNEL_CS;
regs.flags = X86_EFLAGS_IF;
/* Ok, create the new process.. */
return do_fork(flags | CLONE_VM | CLONE_UNTRACED, ~0UL, &regs, 0, NULL, NULL);
}
EXPORT_SYMBOL(kernel_thread);
void release_thread(struct task_struct *dead_task) void release_thread(struct task_struct *dead_task)
{ {
if (dead_task->mm) { if (dead_task->mm) {
......
...@@ -17,8 +17,6 @@ ...@@ -17,8 +17,6 @@
EXPORT_SYMBOL(mcount); EXPORT_SYMBOL(mcount);
#endif #endif
EXPORT_SYMBOL(kernel_thread);
EXPORT_SYMBOL(__get_user_1); EXPORT_SYMBOL(__get_user_1);
EXPORT_SYMBOL(__get_user_2); EXPORT_SYMBOL(__get_user_2);
EXPORT_SYMBOL(__get_user_4); EXPORT_SYMBOL(__get_user_4);
......
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