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         UNWINDER_ORC,
  20 };
  21
  22 struct unwind_state {
  23         char type; /* UNWINDER_XXX */
  24         struct stack_info stack_info;
  25         struct task_struct *task;
  26         bool first, error, reset;
  27         int graph_idx;
  28         unsigned long sp, fp, pc, ra;
  29 };
  30
  31 bool default_next_frame(struct unwind_state *state);
  32
  33 void unwind_start(struct unwind_state *state,
  34                   struct task_struct *task, struct pt_regs *regs);
  35 bool unwind_next_frame(struct unwind_state *state);
  36 unsigned long unwind_get_return_address(struct unwind_state *state);
  37
  38 static inline bool unwind_done(struct unwind_state *state)
  39 {
  40         return state->stack_info.type == STACK_TYPE_UNKNOWN;
  41 }
  42
  43 static inline bool unwind_error(struct unwind_state *state)
  44 {
  45         return state->error;
  46 }
  47
  48 #define GRAPH_FAKE_OFFSET (sizeof(struct pt_regs) - offsetof(struct pt_regs, regs[1]))
  49
  50 static inline unsigned long unwind_graph_addr(struct unwind_state *state,
  51                                         unsigned long pc, unsigned long cfa)
  52 {
  53         return ftrace_graph_ret_addr(state->task, &state->graph_idx,
  54                                      pc, (unsigned long *)(cfa - GRAPH_FAKE_OFFSET));
  55 }
  56
  57 static __always_inline void __unwind_start(struct unwind_state *state,
  58                                         struct task_struct *task, struct pt_regs *regs)
  59 {
  60         memset(state, 0, sizeof(*state));
  61         if (regs) {
  62                 state->sp = regs->regs[3];
  63                 state->pc = regs->csr_era;
  64                 state->ra = regs->regs[1];
  65                 state->fp = regs->regs[22];
  66         } else if (task && task != current) {
  67                 state->sp = thread_saved_fp(task);
  68                 state->pc = thread_saved_ra(task);
  69                 state->ra = 0;
  70                 state->fp = 0;
  71         } else {
  72                 state->sp = (unsigned long)__builtin_frame_address(0);
  73                 state->pc = (unsigned long)__builtin_return_address(0);
  74                 state->ra = 0;
  75                 state->fp = 0;
  76         }
  77         state->task = task;
  78         get_stack_info(state->sp, state->task, &state->stack_info);
  79         state->pc = unwind_graph_addr(state, state->pc, state->sp);
  80 }
  81
  82 static __always_inline unsigned long __unwind_get_return_address(struct unwind_state *state)
  83 {
  84         if (unwind_done(state))
  85                 return 0;
  86
  87         return __kernel_text_address(state->pc) ? state->pc : 0;
  88 }
  89
  90 #ifdef CONFIG_UNWINDER_ORC
  91 void unwind_init(void);
  92 void unwind_module_init(struct module *mod, void *orc_ip, size_t orc_ip_size, void *orc, size_t orc_size);
  93 #else
  94 static inline void unwind_init(void) {}
  95 static inline void unwind_module_init(struct module *mod, void *orc_ip, size_t orc_ip_size, void *orc, size_t orc_size) {}
  96 #endif
  97
  98 #endif /* _ASM_UNWIND_H */