x86, 32-bit: Use same regs as 64-bit for kernel_thread_helper

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>

diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S
index cb12b9b..44a8e0d 100644 (file)
--- a/arch/x86/kernel/entry_32.S
+++ b/arch/x86/kernel/entry_32.S
@@ -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

diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index 506d5a7..bd874d2 100644 (file)
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -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);
@@ -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;