// SPDX-License-Identifier: GPL-2.0-only/* * Copyright (C) 2008 ARM Limited * Copyright (C) 2014 Regents of the University of California */ #include <linux/export.h>#include <linux/kallsyms.h>#include <linux/sched.h>#include <linux/sched/debug.h>#include <linux/sched/task_stack.h>#include <linux/stacktrace.h>#include <linux/ftrace.h> #include <asm/stacktrace.h> register unsigned long sp_in_global __asm__("sp"); #ifdef CONFIG_FRAME_POINTER void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs,			     bool (*fn)(void *, unsigned long), 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 == current) {		fp = (unsigned long)__builtin_frame_address(1);		sp = (unsigned long)__builtin_frame_address(0);		pc = (unsigned long)__builtin_return_address(0);	} else {		/* task blocked in __switch_to */		fp = task->thread.s[0];		sp = task->thread.sp;		pc = task->thread.ra;	} 	for (;;) {		unsigned long low, high;		struct stackframe *frame; 		if (unlikely(!__kernel_text_address(pc) || !fn(arg, pc)))			break; 		/* Validate frame pointer */		low = sp + sizeof(struct stackframe);		high = ALIGN(sp, THREAD_SIZE);		if (unlikely(fp < low || fp > high || fp & 0x7))			break;		/* Unwind stack frame */		frame = (struct stackframe *)fp - 1;		sp = fp;		if (regs && (regs->epc == pc) && (frame->fp & 0x7)) {			fp = frame->ra;			pc = regs->ra;		} else {			fp = frame->fp;			pc = ftrace_graph_ret_addr(current, NULL, frame->ra,						   (unsigned long *)(fp - 8));		} 	}} #else /* !CONFIG_FRAME_POINTER */ void notrace walk_stackframe(struct task_struct *task,	struct pt_regs *regs, bool (*fn)(void *, unsigned long), 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) {		sp = sp_in_global;		pc = (unsigned long)walk_stackframe;	} else {		/* task blocked in __switch_to */		sp = task->thread.sp;		pc = task->thread.ra;	} 	if (unlikely(sp & 0x7))		return; 	ksp = (unsigned long *)sp;	while (!kstack_end(ksp)) {		if (__kernel_text_address(pc) && unlikely(!fn(arg, pc)))			break;		pc = (*ksp++) - 0x4;	}} #endif /* CONFIG_FRAME_POINTER */ static bool print_trace_address(void *arg, unsigned long pc){	const char *loglvl = arg; 	print_ip_sym(loglvl, pc);	return true;} noinline void dump_backtrace(struct pt_regs *regs, struct task_struct *task,		    const char *loglvl){	walk_stackframe(task, regs, print_trace_address, (void *)loglvl);} void show_stack(struct task_struct *task, unsigned long *sp, const char *loglvl){	pr_cont("%sCall Trace:\n", loglvl);	dump_backtrace(NULL, task, loglvl);} static bool save_wchan(void *arg, unsigned long pc){	if (!in_sched_functions(pc)) {		unsigned long *p = arg;		*p = pc;		return false;	}	return true;} 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_STACKTRACE noinline void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie,		     struct task_struct *task, struct pt_regs *regs){	walk_stackframe(task, regs, consume_entry, cookie);} #endif /* CONFIG_STACKTRACE */