#include <linux/module.h>#include <linux/sched.h>#include <linux/stacktrace.h> #include "stacktrace.h" int walk_stackframe(unsigned long fp, unsigned long low, unsigned long high,		    int (*fn)(struct stackframe *, void *), void *data){	struct stackframe *frame; 	do {		/*		 * Check current frame pointer is within bounds		 */		if (fp < (low + 12) || fp + 4 >= high)			break; 		frame = (struct stackframe *)(fp - 12); 		if (fn(frame, data))			break; 		/*		 * Update the low bound - the next frame must always		 * be at a higher address than the current frame.		 */		low = fp + 4;		fp = frame->fp;	} while (fp); 	return 0;}EXPORT_SYMBOL(walk_stackframe); #ifdef CONFIG_STACKTRACEstruct stack_trace_data {	struct stack_trace *trace;	unsigned int skip;}; static int save_trace(struct stackframe *frame, void *d){	struct stack_trace_data *data = d;	struct stack_trace *trace = data->trace; 	if (data->skip) {		data->skip--;		return 0;	} 	trace->entries[trace->nr_entries++] = frame->lr; 	return trace->nr_entries >= trace->max_entries;} void save_stack_trace(struct stack_trace *trace){	struct stack_trace_data data;	unsigned long fp, base; 	data.trace = trace;	data.skip = trace->skip;	base = (unsigned long)task_stack_page(current);	asm("mov %0, fp" : "=r" (fp)); 	walk_stackframe(fp, base, base + THREAD_SIZE, save_trace, &data);}#endif