[ARM] Add stacktrace support and make oprofile use it

Add support for stacktrace.  Use the new stacktrace code with
oprofile instead of it's version; there's no point having
multiple versions of stacktracing in the kernel.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 17 insertions, 52 deletions

diff --git a/arch/arm/oprofile/backtrace.c b/arch/arm/oprofile/backtrace.c
index 7c22c12618cc..f5ebf30151fa 100644
--- a/arch/arm/oprofile/backtrace.c
+++ b/arch/arm/oprofile/backtrace.c
@@ -19,6 +19,19 @@
 #include <asm/ptrace.h>
 #include <asm/uaccess.h>
 
+#include "../kernel/stacktrace.h"
+
+static int report_trace(struct stackframe *frame, void *d)
+{
+        unsigned int *depth = d;
+
+        if (*depth) {
+                oprofile_add_trace(frame->lr);
+                (*depth)--;
+        }
+
+        return *depth == 0;
+}
 
 /*
  * The registers we're interested in are at the end of the variable
@@ -32,21 +45,6 @@ struct frame_tail {
         unsigned long lr;
 } __attribute__((packed));
 
-
-#ifdef CONFIG_FRAME_POINTER
-static struct frame_tail* kernel_backtrace(struct frame_tail *tail)
-{
-        oprofile_add_trace(tail->lr);
-
-        /* frame pointers should strictly progress back up the stack
-         * (towards higher addresses) */
-        if (tail >= tail->fp)
-                return NULL;
-
-        return tail->fp-1;
-}
-#endif
-
 static struct frame_tail* user_backtrace(struct frame_tail *tail)
 {
         struct frame_tail buftail[2];
@@ -67,47 +65,14 @@ static struct frame_tail* user_backtrace(struct frame_tail *tail)
         return buftail[0].fp-1;
 }
 
-/*
- * |             | /\ Higher addresses
- * |             |
- * --------------- stack base (address of current_thread_info)
- * | thread info |
- * .             .
- * |    stack    |
- * --------------- saved regs->ARM_fp value if valid (frame_tail address)
- * .             .
- * --------------- struct pt_regs stored on stack (struct pt_regs *)
- * |             |
- * .             .
- * |             |
- * --------------- %esp
- * |             |
- * |             | \/ Lower addresses
- *
- * Thus, &pt_regs <-> stack base restricts the valid(ish) fp values
- */
-static int valid_kernel_stack(struct frame_tail *tail, struct pt_regs *regs)
-{
-        unsigned long tailaddr = (unsigned long)tail;
-        unsigned long stack = (unsigned long)regs;
-        unsigned long stack_base = (stack & ~(THREAD_SIZE - 1)) + THREAD_SIZE;
-
-        return (tailaddr > stack) && (tailaddr < stack_base);
-}
-
 void arm_backtrace(struct pt_regs * const regs, unsigned int depth)
 {
-        struct frame_tail *tail;
-
-        tail = ((struct frame_tail *) regs->ARM_fp) - 1;
+        struct frame_tail *tail = ((struct frame_tail *) regs->ARM_fp) - 1;
 
         if (!user_mode(regs)) {
-
-#ifdef CONFIG_FRAME_POINTER
-                while (depth-- && tail && valid_kernel_stack(tail, regs)) {
-                        tail = kernel_backtrace(tail);
-                }
-#endif
+                unsigned long base = ((unsigned long)regs) & ~(THREAD_SIZE - 1);
+                walk_stackframe(regs->ARM_fp, base, base + THREAD_SIZE,
+                                report_trace, &depth);
                 return;
         }