Merge commit '85082fd7cbe3173198aac0eb5e85ab1edcc6352c' into test-build
[linux-2.6.git] / arch / powerpc / kernel / stacktrace.c
1 /*
2  * Stack trace utility
3  *
4  * Copyright 2008 Christoph Hellwig, IBM Corp.
5  *
6  *
7  *      This program is free software; you can redistribute it and/or
8  *      modify it under the terms of the GNU General Public License
9  *      as published by the Free Software Foundation; either version
10  *      2 of the License, or (at your option) any later version.
11  */
12
13 #include <linux/module.h>
14 #include <linux/sched.h>
15 #include <linux/stacktrace.h>
16 #include <asm/ptrace.h>
17 #include <asm/processor.h>
18
19 /*
20  * Save stack-backtrace addresses into a stack_trace buffer.
21  */
22 static void save_context_stack(struct stack_trace *trace, unsigned long sp,
23                         struct task_struct *tsk, int savesched)
24 {
25         for (;;) {
26                 unsigned long *stack = (unsigned long *) sp;
27                 unsigned long newsp, ip;
28
29                 if (!validate_sp(sp, tsk, STACK_FRAME_OVERHEAD))
30                         return;
31
32                 newsp = stack[0];
33                 ip = stack[STACK_FRAME_LR_SAVE];
34
35                 if (savesched || !in_sched_functions(ip)) {
36                         if (!trace->skip)
37                                 trace->entries[trace->nr_entries++] = ip;
38                         else
39                                 trace->skip--;
40                 }
41
42                 if (trace->nr_entries >= trace->max_entries)
43                         return;
44
45                 sp = newsp;
46         }
47 }
48
49 void save_stack_trace(struct stack_trace *trace)
50 {
51         unsigned long sp;
52
53         asm("mr %0,1" : "=r" (sp));
54
55         save_context_stack(trace, sp, current, 1);
56 }
57 EXPORT_SYMBOL_GPL(save_stack_trace);
58
59 void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
60 {
61         save_context_stack(trace, tsk->thread.regs->gpr[1], tsk, 0);
62 }
63 EXPORT_SYMBOL_GPL(save_stack_trace_tsk);