release/src-rt-6.x.4708/linux/linux-2.6.36/arch/blackfin/kernel/stacktrace.c

   1 /*
   2  * Blackfin stacktrace code (mostly copied from avr32)
   3  *
   4  * Copyright 2009 Analog Devices Inc.
   5  * Licensed under the GPL-2 or later.
   6  */
   7
   8 #include <linux/sched.h>
   9 #include <linux/stacktrace.h>
  10 #include <linux/thread_info.h>
  11 #include <linux/module.h>
  12
  13 register unsigned long current_frame_pointer asm("FP");
  14
  15 struct stackframe {
  16         unsigned long fp;
  17         unsigned long rets;
  18 };
  19
  20 /*
  21  * Save stack-backtrace addresses into a stack_trace buffer.
  22  */
  23 void save_stack_trace(struct stack_trace *trace)
  24 {
  25         unsigned long low, high;
  26         unsigned long fp;
  27         struct stackframe *frame;
  28         int skip = trace->skip;
  29
  30         low = (unsigned long)task_stack_page(current);
  31         high = low + THREAD_SIZE;
  32         fp = current_frame_pointer;
  33
  34         while (fp >= low && fp <= (high - sizeof(*frame))) {
  35                 frame = (struct stackframe *)fp;
  36
  37                 if (skip) {
  38                         skip--;
  39                 } else {
  40                         trace->entries[trace->nr_entries++] = frame->rets;
  41                         if (trace->nr_entries >= trace->max_entries)
  42                                 break;
  43                 }
  44
  45                 /*
  46                  * The next frame must be at a higher address than the
  47                  * current frame.
  48                  */
  49                 low = fp + sizeof(*frame);
  50                 fp = frame->fp;
  51         }
  52 }
  53 EXPORT_SYMBOL_GPL(save_stack_trace);