1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * arch/arm/kernel/return_address.c 4 * 5 * Copyright (C) 2009 Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de> 6 * for Pengutronix 7 */ 8 #include <linux/export.h> 9 #include <linux/ftrace.h> 10 11 #if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND) 12 #include <linux/sched.h> 13 14 #include <asm/stacktrace.h> 15 16 struct return_address_data { 17 unsigned int level; 18 void *addr; 19 }; 20 save_return_addr(struct stackframe * frame,void * d)21static int save_return_addr(struct stackframe *frame, void *d) 22 { 23 struct return_address_data *data = d; 24 25 if (!data->level) { 26 data->addr = (void *)frame->pc; 27 28 return 1; 29 } else { 30 --data->level; 31 return 0; 32 } 33 } 34 return_address(unsigned int level)35void *return_address(unsigned int level) 36 { 37 struct return_address_data data; 38 struct stackframe frame; 39 40 data.level = level + 2; 41 data.addr = NULL; 42 43 frame.fp = (unsigned long)__builtin_frame_address(0); 44 frame.sp = current_stack_pointer; 45 frame.lr = (unsigned long)__builtin_return_address(0); 46 frame.pc = (unsigned long)return_address; 47 48 walk_stackframe(&frame, save_return_addr, &data); 49 50 if (!data.level) 51 return data.addr; 52 else 53 return NULL; 54 } 55 56 #endif /* if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND) */ 57 58 EXPORT_SYMBOL_GPL(return_address); 59