arch/loongarch/kernel/unwind_guess.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2022 Loongson Technology Corporation Limited
   4  */
   5 #include <linux/kernel.h>
   6
   7 #include <asm/unwind.h>
   8
   9 unsigned long unwind_get_return_address(struct unwind_state *state)
  10 {
  11         if (unwind_done(state))
  12                 return 0;
  13         else if (state->first)
  14                 return state->pc;
  15
  16         return *(unsigned long *)(state->sp);
  17 }
  18 EXPORT_SYMBOL_GPL(unwind_get_return_address);
  19
  20 void unwind_start(struct unwind_state *state, struct task_struct *task,
  21                     struct pt_regs *regs)
  22 {
  23         memset(state, 0, sizeof(*state));
  24
  25         if (regs) {
  26                 state->sp = regs->regs[3];
  27                 state->pc = regs->csr_era;
  28         }
  29
  30         state->task = task;
  31         state->first = true;
  32
  33         get_stack_info(state->sp, state->task, &state->stack_info);
  34
  35         if (!unwind_done(state) && !__kernel_text_address(state->pc))
  36                 unwind_next_frame(state);
  37 }
  38 EXPORT_SYMBOL_GPL(unwind_start);
  39
  40 bool unwind_next_frame(struct unwind_state *state)
  41 {
  42         struct stack_info *info = &state->stack_info;
  43         unsigned long addr;
  44
  45         if (unwind_done(state))
  46                 return false;
  47
  48         if (state->first)
  49                 state->first = false;
  50
  51         do {
  52                 for (state->sp += sizeof(unsigned long);
  53                      state->sp < info->end;
  54                      state->sp += sizeof(unsigned long)) {
  55                         addr = *(unsigned long *)(state->sp);
  56
  57                         if (__kernel_text_address(addr))
  58                                 return true;
  59                 }
  60
  61                 state->sp = info->next_sp;
  62
  63         } while (!get_stack_info(state->sp, state->task, info));
  64
  65         return false;
  66 }
  67 EXPORT_SYMBOL_GPL(unwind_next_frame);