LXR linux/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
  13register unsigned long current_frame_pointer asm("FP");
  14
  15struct stackframe {
  16        unsigned long fp;
  17        unsigned long rets;
  18};
  19
  20/*
  21 * Save stack-backtrace addresses into a stack_trace buffer.
  22 */
  23void 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}
  53EXPORT_SYMBOL_GPL(save_stack_trace);
  54