/*
   * Stack trace management functions
   *
   * Copyright (C) 2007 Atmel Corporation
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   */
  #include <linux/sched.h>
  #include <linux/stacktrace.h>
  #include <linux/thread_info.h>

  #include <linux/module.h>

  
  register unsigned long current_frame_pointer asm("r7");
  
  struct stackframe {
  	unsigned long lr;
  	unsigned long fp;
  };
  
  /*
   * Save stack-backtrace addresses into a stack_trace buffer.
   */
  void save_stack_trace(struct stack_trace *trace)
  {
  	unsigned long low, high;
  	unsigned long fp;
  	struct stackframe *frame;
  	int skip = trace->skip;
  
  	low = (unsigned long)task_stack_page(current);
  	high = low + THREAD_SIZE;
  	fp = current_frame_pointer;
  
  	while (fp >= low && fp <= (high - 8)) {
  		frame = (struct stackframe *)fp;
  
  		if (skip) {
  			skip--;
  		} else {
  			trace->entries[trace->nr_entries++] = frame->lr;
  			if (trace->nr_entries >= trace->max_entries)
  				break;
  		}
  
  		/*
  		 * The next frame must be at a higher address than the
  		 * current frame.
  		 */
  		low = fp + 8;
  		fp = frame->fp;
  	}
  }

  EXPORT_SYMBOL_GPL(save_stack_trace);