// SPDX-License-Identifier: GPL-2.0-only /* * This code come from arch/arm64/kernel/return_address.c * * Copyright (C) 2023 SiFive. */ #include <linux/export.h> #include <linux/kprobes.h> #include <linux/stacktrace.h> struct return_address_data { unsigned int level; void *addr; }; static bool save_return_addr(void *d, unsigned long pc) { struct return_address_data *data = d; if (!data->level) { data->addr = (void *)pc; return false; } --data->level; return true; } NOKPROBE_SYMBOL(save_return_addr); noinline void *return_address(unsigned int level) { struct return_address_data data; data.level = level + 3; data.addr = NULL; arch_stack_walk(save_return_addr, &data, current, NULL); if (!data.level) return data.addr; else return NULL; } EXPORT_SYMBOL_GPL(return_address); NOKPROBE_SYMBOL(return_address);