Merge commit 'origin/master'
[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 <linux/module.h>
17 #include <asm/ptrace.h>
18 #include <asm/processor.h>
19
20 /*
21  * Save stack-backtrace addresses into a stack_trace buffer.
22  */
23 static void save_context_stack(struct stack_trace *trace, unsigned long sp,
24                         struct task_struct *tsk, int savesched)
25 {
26         for (;;) {
27                 unsigned long *stack = (unsigned long *) sp;
28                 unsigned long newsp, ip;
29
30                 if (!validate_sp(sp, tsk, STACK_FRAME_OVERHEAD))
31                         return;
32
33                 newsp = stack[0];
34                 ip = stack[STACK_FRAME_LR_SAVE];
35
36                 if (savesched || !in_sched_functions(ip)) {
37                         if (!trace->skip)
38                                 trace->entries[trace->nr_entries++] = ip;
39                         else
40                                 trace->skip--;
41                 }
42
43                 if (trace->nr_entries >= trace->max_entries)
44                         return;
45
46                 sp = newsp;
47         }
48 }
49
50 void save_stack_trace(struct stack_trace *trace)
51 {
52         unsigned long sp;
53
54         asm("mr %0,1" : "=r" (sp));
55
56         save_context_stack(trace, sp, current, 1);
57 }
58 EXPORT_SYMBOL_GPL(save_stack_trace);
59
60 void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
61 {
62         save_context_stack(trace, tsk->thread.regs->gpr[1], tsk, 0);
63 }
64 EXPORT_SYMBOL_GPL(save_stack_trace_tsk);