// SPDX-License-Identifier: GPL-2.0// Copyright (C) 2005-2017 Andes Technology Corporation #include <linux/sched/debug.h>#include <linux/sched/task_stack.h>#include <linux/stacktrace.h>#include <linux/ftrace.h> void save_stack_trace(struct stack_trace *trace){	save_stack_trace_tsk(current, trace);}EXPORT_SYMBOL_GPL(save_stack_trace); void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace){	unsigned long *fpn;	int skip = trace->skip;	int savesched;	int graph_idx = 0; 	if (tsk == current) {		__asm__ __volatile__("\tori\t%0, $fp, #0\n":"=r"(fpn));		savesched = 1;	} else {		fpn = (unsigned long *)thread_saved_fp(tsk);		savesched = 0;	} 	while (!kstack_end(fpn) && !((unsigned long)fpn & 0x3)	       && (fpn >= (unsigned long *)TASK_SIZE)) {		unsigned long lpp, fpp; 		lpp = fpn[LP_OFFSET];		fpp = fpn[FP_OFFSET];		if (!__kernel_text_address(lpp))			break;		else			lpp = ftrace_graph_ret_addr(tsk, &graph_idx, lpp, NULL); 		if (savesched || !in_sched_functions(lpp)) {			if (skip) {				skip--;			} else {				trace->entries[trace->nr_entries++] = lpp;				if (trace->nr_entries >= trace->max_entries)					break;			}		}		fpn = (unsigned long *)fpp;	}}EXPORT_SYMBOL_GPL(save_stack_trace_tsk);