arch/riscv/kernel/return_address.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * This code come from arch/arm64/kernel/return_address.c
   4  *
   5  * Copyright (C) 2023 SiFive.
   6  */
   7
   8 #include <linux/export.h>
   9 #include <linux/kprobes.h>
  10 #include <linux/stacktrace.h>
  11
  12 struct return_address_data {
  13         unsigned int level;
  14         void *addr;
  15 };
  16
  17 static bool save_return_addr(void *d, unsigned long pc)
  18 {
  19         struct return_address_data *data = d;
  20
  21         if (!data->level) {
  22                 data->addr = (void *)pc;
  23                 return false;
  24         }
  25
  26         --data->level;
  27
  28         return true;
  29 }
  30 NOKPROBE_SYMBOL(save_return_addr);
  31
  32 noinline void *return_address(unsigned int level)
  33 {
  34         struct return_address_data data;
  35
  36         data.level = level + 3;
  37         data.addr = NULL;
  38
  39         arch_stack_walk(save_return_addr, &data, current, NULL);
  40
  41         if (!data.level)
  42                 return data.addr;
  43         else
  44                 return NULL;
  45
  46 }
  47 EXPORT_SYMBOL_GPL(return_address);
  48 NOKPROBE_SYMBOL(return_address);