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 */
99
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