Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes...
[linux-2.6] / arch / mips / kernel / stacktrace.c
1 /*
2  * arch/mips/kernel/stacktrace.c
3  *
4  * Stack trace management functions
5  *
6  *  Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
7  */
8 #include <linux/sched.h>
9 #include <linux/stacktrace.h>
10 #include <linux/module.h>
11 #include <asm/stacktrace.h>
12
13 /*
14  * Save stack-backtrace addresses into a stack_trace buffer:
15  */
16 static void save_raw_context_stack(struct stack_trace *trace,
17         unsigned long reg29)
18 {
19         unsigned long *sp = (unsigned long *)reg29;
20         unsigned long addr;
21
22         while (!kstack_end(sp)) {
23                 addr = *sp++;
24                 if (__kernel_text_address(addr)) {
25                         if (trace->skip > 0)
26                                 trace->skip--;
27                         else
28                                 trace->entries[trace->nr_entries++] = addr;
29                         if (trace->nr_entries >= trace->max_entries)
30                                 break;
31                 }
32         }
33 }
34
35 static void save_context_stack(struct stack_trace *trace,
36         struct task_struct *tsk, struct pt_regs *regs)
37 {
38         unsigned long sp = regs->regs[29];
39 #ifdef CONFIG_KALLSYMS
40         unsigned long ra = regs->regs[31];
41         unsigned long pc = regs->cp0_epc;
42
43         if (raw_show_trace || !__kernel_text_address(pc)) {
44                 unsigned long stack_page =
45                         (unsigned long)task_stack_page(tsk);
46                 if (stack_page && sp >= stack_page &&
47                     sp <= stack_page + THREAD_SIZE - 32)
48                         save_raw_context_stack(trace, sp);
49                 return;
50         }
51         do {
52                 if (trace->skip > 0)
53                         trace->skip--;
54                 else
55                         trace->entries[trace->nr_entries++] = pc;
56                 if (trace->nr_entries >= trace->max_entries)
57                         break;
58                 pc = unwind_stack(tsk, &sp, pc, &ra);
59         } while (pc);
60 #else
61         save_raw_context_stack(trace, sp);
62 #endif
63 }
64
65 /*
66  * Save stack-backtrace addresses into a stack_trace buffer.
67  */
68 void save_stack_trace(struct stack_trace *trace)
69 {
70         save_stack_trace_tsk(current, trace);
71 }
72 EXPORT_SYMBOL_GPL(save_stack_trace);
73
74 void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
75 {
76         struct pt_regs dummyregs;
77         struct pt_regs *regs = &dummyregs;
78
79         WARN_ON(trace->nr_entries || !trace->max_entries);
80
81         if (tsk != current) {
82                 regs->regs[29] = tsk->thread.reg29;
83                 regs->regs[31] = 0;
84                 regs->cp0_epc = tsk->thread.reg31;
85         } else
86                 prepare_frametrace(regs);
87         save_context_stack(trace, tsk, regs);
88 }
89 EXPORT_SYMBOL_GPL(save_stack_trace_tsk);