// SPDX-License-Identifier: GPL-2.0 #include <linux/sched/debug.h>#include <linux/sched/task_stack.h>#include <linux/stacktrace.h>#include <linux/ftrace.h>#include <linux/ptrace.h> #ifdef CONFIG_FRAME_POINTER struct stackframe {	unsigned long fp;	unsigned long ra;}; void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs,			     bool (*fn)(unsigned long, void *), void *arg){	unsigned long fp, sp, pc; 	if (regs) {		fp = frame_pointer(regs);		sp = user_stack_pointer(regs);		pc = instruction_pointer(regs);	} else if (task == NULL || task == current) {		const register unsigned long current_sp __asm__ ("sp");		const register unsigned long current_fp __asm__ ("r8");		fp = current_fp;		sp = current_sp;		pc = (unsigned long)walk_stackframe;	} else {		/* task blocked in __switch_to */		fp = thread_saved_fp(task);		sp = thread_saved_sp(task);		pc = thread_saved_lr(task);	} 	for (;;) {		unsigned long low, high;		struct stackframe *frame; 		if (unlikely(!__kernel_text_address(pc) || fn(pc, arg)))			break; 		/* Validate frame pointer */		low = sp;		high = ALIGN(sp, THREAD_SIZE);		if (unlikely(fp < low || fp > high || fp & 0x3))			break;		/* Unwind stack frame */		frame = (struct stackframe *)fp;		sp = fp;		fp = frame->fp;		pc = ftrace_graph_ret_addr(current, NULL, frame->ra,					   (unsigned long *)(fp - 8));	}} #else /* !CONFIG_FRAME_POINTER */ static void notrace walk_stackframe(struct task_struct *task,	struct pt_regs *regs, bool (*fn)(unsigned long, void *), void *arg){	unsigned long sp, pc;	unsigned long *ksp; 	if (regs) {		sp = user_stack_pointer(regs);		pc = instruction_pointer(regs);	} else if (task == NULL || task == current) {		const register unsigned long current_sp __asm__ ("sp");		sp = current_sp;		pc = (unsigned long)walk_stackframe;	} else {		/* task blocked in __switch_to */		sp = thread_saved_sp(task);		pc = thread_saved_lr(task);	} 	if (unlikely(sp & 0x3))		return; 	ksp = (unsigned long *)sp;	while (!kstack_end(ksp)) {		if (__kernel_text_address(pc) && unlikely(fn(pc, arg)))			break;		pc = (*ksp++) - 0x4;	}}#endif /* CONFIG_FRAME_POINTER */ static bool print_trace_address(unsigned long pc, void *arg){	print_ip_sym((const char *)arg, pc);	return false;} void show_stack(struct task_struct *task, unsigned long *sp, const char *loglvl){	pr_cont("Call Trace:\n");	walk_stackframe(task, NULL, print_trace_address, (void *)loglvl);} static bool save_wchan(unsigned long pc, void *arg){	if (!in_sched_functions(pc)) {		unsigned long *p = arg;		*p = pc;		return true;	}	return false;} unsigned long get_wchan(struct task_struct *task){	unsigned long pc = 0; 	if (likely(task && task != current && task->state != TASK_RUNNING))		walk_stackframe(task, NULL, save_wchan, &pc);	return pc;} #ifdef CONFIG_STACKTRACEstatic bool __save_trace(unsigned long pc, void *arg, bool nosched){	struct stack_trace *trace = arg; 	if (unlikely(nosched && in_sched_functions(pc)))		return false;	if (unlikely(trace->skip > 0)) {		trace->skip--;		return false;	} 	trace->entries[trace->nr_entries++] = pc;	return (trace->nr_entries >= trace->max_entries);} static bool save_trace(unsigned long pc, void *arg){	return __save_trace(pc, arg, false);} /* * Save stack-backtrace addresses into a stack_trace buffer. */void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace){	walk_stackframe(tsk, NULL, save_trace, trace);}EXPORT_SYMBOL_GPL(save_stack_trace_tsk); void save_stack_trace(struct stack_trace *trace){	save_stack_trace_tsk(NULL, trace);}EXPORT_SYMBOL_GPL(save_stack_trace); #endif /* CONFIG_STACKTRACE */