commit 0cb91a2293648507886563ccb91979cfc94d6a4b
author Andi Kleen <ak@suse.de> Tue Sep 26 10:52:28 2006 +0200
committer Andi Kleen <andi@basil.nowhere.org> Tue Sep 26 10:52:28 2006 +0200
tree f2a994f8b874e3c81c5519d445a0c5fa5522e4b5
parent c16b63e09d9d03158e0a92e961234e94c4862620

[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>

arch/i386/kernel/time.c

diff --git a/arch/i386/kernel/time.c b/arch/i386/kernel/time.c
index edd00f6..5af802e 100644
--- a/arch/i386/kernel/time.c
+++ b/arch/i386/kernel/time.c
@@ -130,18 +130,33 @@
 
 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