// SPDX-License-Identifier: GPL-2.0/* * Stack trace management functions * * Copyright (C) 2022 Loongson Technology Corporation Limited */#include <linux/sched.h>#include <linux/stacktrace.h>#include <linux/uaccess.h> #include <asm/stacktrace.h>#include <asm/unwind.h> void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie,		     struct task_struct *task, struct pt_regs *regs){	unsigned long addr;	struct pt_regs dummyregs;	struct unwind_state state; 	if (!regs) {		regs = &dummyregs; 		if (task == current) {			regs->regs[3] = (unsigned long)__builtin_frame_address(0);			regs->csr_era = (unsigned long)__builtin_return_address(0);		} else {			regs->regs[3] = thread_saved_fp(task);			regs->csr_era = thread_saved_ra(task);		}		regs->regs[1] = 0;		regs->regs[22] = 0;	} 	for (unwind_start(&state, task, regs);	     !unwind_done(&state); unwind_next_frame(&state)) {		addr = unwind_get_return_address(&state);		if (!addr || !consume_entry(cookie, addr))			break;	}} int arch_stack_walk_reliable(stack_trace_consume_fn consume_entry,			     void *cookie, struct task_struct *task){	unsigned long addr;	struct pt_regs dummyregs;	struct pt_regs *regs = &dummyregs;	struct unwind_state state; 	if (task == current) {		regs->regs[3] = (unsigned long)__builtin_frame_address(0);		regs->csr_era = (unsigned long)__builtin_return_address(0);		regs->regs[22] = 0;	} else {		regs->regs[3] = thread_saved_fp(task);		regs->csr_era = thread_saved_ra(task);		regs->regs[22] = task->thread.reg22;	}	regs->regs[1] = 0; 	for (unwind_start(&state, task, regs);	     !unwind_done(&state) && !unwind_error(&state); unwind_next_frame(&state)) {		addr = unwind_get_return_address(&state); 		/*		 * A NULL or invalid return address probably means there's some		 * generated code which __kernel_text_address() doesn't know about.		 */		if (!addr)			return -EINVAL; 		if (!consume_entry(cookie, addr))			return -EINVAL;	} 	/* Check for stack corruption */	if (unwind_error(&state))		return -EINVAL; 	return 0;} static intcopy_stack_frame(unsigned long fp, struct stack_frame *frame){	int ret = 1;	unsigned long err;	unsigned long __user *user_frame_tail; 	user_frame_tail = (unsigned long *)(fp - sizeof(struct stack_frame));	if (!access_ok(user_frame_tail, sizeof(*frame)))		return 0; 	pagefault_disable();	err = (__copy_from_user_inatomic(frame, user_frame_tail, sizeof(*frame)));	if (err || (unsigned long)user_frame_tail >= frame->fp)		ret = 0;	pagefault_enable(); 	return ret;} void arch_stack_walk_user(stack_trace_consume_fn consume_entry, void *cookie,			  const struct pt_regs *regs){	unsigned long fp = regs->regs[22]; 	while (fp && !((unsigned long)fp & 0xf)) {		struct stack_frame frame; 		frame.fp = 0;		frame.ra = 0;		if (!copy_stack_frame(fp, &frame))			break;		if (!frame.ra)			break;		if (!consume_entry(cookie, frame.ra))			break;		fp = frame.fp;	}}