[ARM] traps: don't call undef hook functions with spinlock held
[linux-2.6] / arch / arm / kernel / stacktrace.c
1 #include <linux/module.h>
2 #include <linux/sched.h>
3 #include <linux/stacktrace.h>
4
5 #include "stacktrace.h"
6
7 int walk_stackframe(unsigned long fp, unsigned long low, unsigned long high,
8                     int (*fn)(struct stackframe *, void *), void *data)
9 {
10         struct stackframe *frame;
11
12         do {
13                 /*
14                  * Check current frame pointer is within bounds
15                  */
16                 if (fp < (low + 12) || fp + 4 >= high)
17                         break;
18
19                 frame = (struct stackframe *)(fp - 12);
20
21                 if (fn(frame, data))
22                         break;
23
24                 /*
25                  * Update the low bound - the next frame must always
26                  * be at a higher address than the current frame.
27                  */
28                 low = fp + 4;
29                 fp = frame->fp;
30         } while (fp);
31
32         return 0;
33 }
34 EXPORT_SYMBOL(walk_stackframe);
35
36 #ifdef CONFIG_STACKTRACE
37 struct stack_trace_data {
38         struct stack_trace *trace;
39         unsigned int no_sched_functions;
40         unsigned int skip;
41 };
42
43 static int save_trace(struct stackframe *frame, void *d)
44 {
45         struct stack_trace_data *data = d;
46         struct stack_trace *trace = data->trace;
47         unsigned long addr = frame->lr;
48
49         if (data->no_sched_functions && in_sched_functions(addr))
50                 return 0;
51         if (data->skip) {
52                 data->skip--;
53                 return 0;
54         }
55
56         trace->entries[trace->nr_entries++] = addr;
57
58         return trace->nr_entries >= trace->max_entries;
59 }
60
61 void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
62 {
63         struct stack_trace_data data;
64         unsigned long fp, base;
65
66         data.trace = trace;
67         data.skip = trace->skip;
68         base = (unsigned long)task_stack_page(tsk);
69
70         if (tsk != current) {
71 #ifdef CONFIG_SMP
72                 /*
73                  * What guarantees do we have here that 'tsk'
74                  * is not running on another CPU?
75                  */
76                 BUG();
77 #else
78                 data.no_sched_functions = 1;
79                 fp = thread_saved_fp(tsk);
80 #endif
81         } else {
82                 data.no_sched_functions = 0;
83                 asm("mov %0, fp" : "=r" (fp));
84         }
85
86         walk_stackframe(fp, base, base + THREAD_SIZE, save_trace, &data);
87         if (trace->nr_entries < trace->max_entries)
88                 trace->entries[trace->nr_entries++] = ULONG_MAX;
89 }
90
91 void save_stack_trace(struct stack_trace *trace)
92 {
93         save_stack_trace_tsk(current, trace);
94 }
95 EXPORT_SYMBOL_GPL(save_stack_trace);
96 #endif