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 skip;
  40 };
  41
  42 static int save_trace(struct stackframe *frame, void *d)
  43 {
  44         struct stack_trace_data *data = d;
  45         struct stack_trace *trace = data->trace;
  46
  47         if (data->skip) {
  48                 data->skip--;
  49                 return 0;
  50         }
  51
  52         trace->entries[trace->nr_entries++] = frame->lr;
  53
  54         return trace->nr_entries >= trace->max_entries;
  55 }
  56
  57 void save_stack_trace(struct stack_trace *trace)
  58 {
  59         struct stack_trace_data data;
  60         unsigned long fp, base;
  61
  62         data.trace = trace;
  63         data.skip = trace->skip;
  64         base = (unsigned long)task_stack_page(current);
  65         asm("mov %0, fp" : "=r" (fp));
  66
  67         walk_stackframe(fp, base, base + THREAD_SIZE, save_trace, &data);
  68 }
  69 #endif