arch/loongarch/include/asm/unwind.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * Most of this ideas comes from x86.
   4  *
   5  * Copyright (C) 2022 Loongson Technology Corporation Limited
   6  */
   7 #ifndef _ASM_UNWIND_H
   8 #define _ASM_UNWIND_H
   9
  10 #include <linux/sched.h>
  11 #include <linux/ftrace.h>
  12
  13 #include <asm/ptrace.h>
  14 #include <asm/stacktrace.h>
  15
  16 enum unwinder_type {
  17         UNWINDER_GUESS,
  18         UNWINDER_PROLOGUE,
  19 };
  20
  21 struct unwind_state {
  22         char type; /* UNWINDER_XXX */
  23         struct stack_info stack_info;
  24         struct task_struct *task;
  25         bool first, error, reset;
  26         int graph_idx;
  27         unsigned long sp, pc, ra;
  28 };
  29
  30 bool default_next_frame(struct unwind_state *state);
  31
  32 void unwind_start(struct unwind_state *state,
  33                   struct task_struct *task, struct pt_regs *regs);
  34 bool unwind_next_frame(struct unwind_state *state);
  35 unsigned long unwind_get_return_address(struct unwind_state *state);
  36
  37 static inline bool unwind_done(struct unwind_state *state)
  38 {
  39         return state->stack_info.type == STACK_TYPE_UNKNOWN;
  40 }
  41
  42 static inline bool unwind_error(struct unwind_state *state)
  43 {
  44         return state->error;
  45 }
  46
  47 #define GRAPH_FAKE_OFFSET (sizeof(struct pt_regs) - offsetof(struct pt_regs, regs[1]))
  48
  49 static inline unsigned long unwind_graph_addr(struct unwind_state *state,
  50                                         unsigned long pc, unsigned long cfa)
  51 {
  52         return ftrace_graph_ret_addr(state->task, &state->graph_idx,
  53                                      pc, (unsigned long *)(cfa - GRAPH_FAKE_OFFSET));
  54 }
  55
  56 static __always_inline void __unwind_start(struct unwind_state *state,
  57                                         struct task_struct *task, struct pt_regs *regs)
  58 {
  59         memset(state, 0, sizeof(*state));
  60         if (regs) {
  61                 state->sp = regs->regs[3];
  62                 state->pc = regs->csr_era;
  63                 state->ra = regs->regs[1];
  64         } else if (task && task != current) {
  65                 state->sp = thread_saved_fp(task);
  66                 state->pc = thread_saved_ra(task);
  67                 state->ra = 0;
  68         } else {
  69                 state->sp = (unsigned long)__builtin_frame_address(0);
  70                 state->pc = (unsigned long)__builtin_return_address(0);
  71                 state->ra = 0;
  72         }
  73         state->task = task;
  74         get_stack_info(state->sp, state->task, &state->stack_info);
  75         state->pc = unwind_graph_addr(state, state->pc, state->sp);
  76 }
  77
  78 static __always_inline unsigned long __unwind_get_return_address(struct unwind_state *state)
  79 {
  80         return unwind_done(state) ? 0 : state->pc;
  81 }
  82 #endif /* _ASM_UNWIND_H */