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         } else if (task && task != current) {
  29                 state->sp = thread_saved_fp(task);
  30                 state->pc = thread_saved_ra(task);
  31         } else {
  32                 state->sp = (unsigned long)__builtin_frame_address(0);
  33                 state->pc = (unsigned long)__builtin_return_address(0);
  34         }
  35
  36         state->task = task;
  37         state->first = true;
  38
  39         get_stack_info(state->sp, state->task, &state->stack_info);
  40
  41         if (!unwind_done(state) && !__kernel_text_address(state->pc))
  42                 unwind_next_frame(state);
  43 }
  44 EXPORT_SYMBOL_GPL(unwind_start);
  45
  46 bool unwind_next_frame(struct unwind_state *state)
  47 {
  48         struct stack_info *info = &state->stack_info;
  49         unsigned long addr;
  50
  51         if (unwind_done(state))
  52                 return false;
  53
  54         if (state->first)
  55                 state->first = false;
  56
  57         do {
  58                 for (state->sp += sizeof(unsigned long);
  59                      state->sp < info->end;
  60                      state->sp += sizeof(unsigned long)) {
  61                         addr = *(unsigned long *)(state->sp);
  62
  63                         if (__kernel_text_address(addr))
  64                                 return true;
  65                 }
  66
  67                 state->sp = info->next_sp;
  68
  69         } while (!get_stack_info(state->sp, state->task, info));
  70
  71         return false;
  72 }
  73 EXPORT_SYMBOL_GPL(unwind_next_frame);