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x86, 32-bit: Use same regs as 64-bit for kernel_thread_helper
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The arg should be in %eax, but that is clobbered by the return value
of clone.  The function pointer can be in any register.  Also, don't
push args onto the stack, since regparm(3) is the normal calling
convention now.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
LKML-Reference: <1260380084-3707-4-git-send-email-brgerst@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
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Brian Gerst authored and H. Peter Anvin committed Dec 10, 2009
1 parent fa4b8f8 commit e840227
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Showing 2 changed files with 6 additions and 10 deletions.
8 changes: 2 additions & 6 deletions arch/x86/kernel/entry_32.S
Original file line number Diff line number Diff line change
Expand Up @@ -1047,12 +1047,8 @@ END(spurious_interrupt_bug)
ENTRY(kernel_thread_helper)
pushl $0 # fake return address for unwinder
CFI_STARTPROC
movl %edx,%eax
push %edx
CFI_ADJUST_CFA_OFFSET 4
call *%ebx
push %eax
CFI_ADJUST_CFA_OFFSET 4
movl %edi,%eax
call *%esi
call do_exit
ud2 # padding for call trace
CFI_ENDPROC
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8 changes: 4 additions & 4 deletions arch/x86/kernel/process_32.c
Original file line number Diff line number Diff line change
Expand Up @@ -193,8 +193,8 @@ void show_regs(struct pt_regs *regs)
}

/*
* This gets run with %bx containing the
* function to call, and %dx containing
* This gets run with %si containing the
* function to call, and %di containing
* the "args".
*/
extern void kernel_thread_helper(void);
Expand All @@ -208,8 +208,8 @@ int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)

memset(&regs, 0, sizeof(regs));

regs.bx = (unsigned long) fn;
regs.dx = (unsigned long) arg;
regs.si = (unsigned long) fn;
regs.di = (unsigned long) arg;

regs.ds = __USER_DS;
regs.es = __USER_DS;
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