[PATCH] i386: Account spinlocks to the caller during profiling for !FP kernels

This ports the algorithm from x86-64 (with improvements) to i386.
Previously this only worked for frame pointer enabled kernels.
But spinlocks have a very simple stack frame that can be manually
analyzed. Do this.

Signed-off-by: Andi Kleen <ak@suse.de>

1 files changed, 19 insertions, 4 deletions

diff --git a/arch/i386/kernel/time.c b/arch/i386/kernel/time.c
index edd00f6cee37..5af802ef00b2 100644
--- a/arch/i386/kernel/time.c
+++ b/arch/i386/kernel/time.c
@@ -130,18 +130,33 @@ static int set_rtc_mmss(unsigned long nowtime)
 
 int timer_ack;
 
-#if defined(CONFIG_SMP) && defined(CONFIG_FRAME_POINTER)
 unsigned long profile_pc(struct pt_regs *regs)
 {
         unsigned long pc = instruction_pointer(regs);
 
-        if (!user_mode_vm(regs) && in_lock_functions(pc))
+#ifdef CONFIG_SMP
+        if (!user_mode_vm(regs) && in_lock_functions(pc)) {
+#ifdef CONFIG_FRAME_POINTER
                 return *(unsigned long *)(regs->ebp + 4);
-
+#else
+                unsigned long *sp;
+                if ((regs->xcs & 3) == 0)
+                        sp = (unsigned long *)&regs->esp;
+                else
+                        sp = (unsigned long *)regs->esp;
+                /* Return address is either directly at stack pointer
+                   or above a saved eflags. Eflags has bits 22-31 zero,
+                   kernel addresses don't. */
+                if (sp[0] >> 22)
+                        return sp[0];
+                if (sp[1] >> 22)
+                        return sp[1];
+#endif
+        }
+#endif
         return pc;
 }
 EXPORT_SYMBOL(profile_pc);
-#endif
 
 /*
  * This is the same as the above, except we _also_ save the current