[PATCH for review] [34/145] i386: Account spinlocks to the caller during profiling for !FP kernels

Andi Kleen
2006-08-10T20:16:10Z

r

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 | 23 +++++++++++++++++++----
include/asm-i386/ptrace.h | 4 ----
kernel/spinlock.c | 5 +++++
3 files changed, 24 insertions(+), 8 deletions(-)

Index: linux/arch/i386/kernel/time.c
===================================================================
--- linux.orig/arch/i386/kernel/time.c
+++ linux/arch/i386/kernel/time.c
@@ -130,18 +130,33 @@ static int set_rtc_mmss(unsigned long no

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
Index: linux/include/asm-i386/ptrace.h
===================================================================
--- linux.orig/include/asm-i386/ptrace.h
+++ linux/include/asm-i386/ptrace.h
@@ -80,11 +80,7 @@ static inline int user_mode_vm(struct pt
return ((regs->xcs & 3) | (regs->eflags & VM_MASK)) != 0;
}
#define instruction_pointer(regs) ((regs)->eip)
-#if defined(CONFIG_SMP) && defined(CONFIG_FRAME_POINTER)
extern unsigned long profile_pc(struct pt_regs *regs);
-#else
-#define profile_pc(regs) instruction_pointer(regs)
-#endif
#endif /* __KERNEL__ */

#endif
Index: linux/kernel/spinlock.c
===================================================================
--- linux.orig/kernel/spinlock.c
+++ linux/kernel/spinlock.c
@@ -7,6 +7,11 @@
*
* This file contains the spinlock/rwlock implementations for the
* SMP and the DEBUG_SPINLOCK cases. (UP-nondebug inlines them)
+ *
+ * Note that some architectures have special knowledge about the
+ * stack frames of these functions in their profile_pc. If you
+ * change anything significant here that could change the stack
+ * frame contact the architecture maintainers.
*/

#include <linux/linkage.h>