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
16enum unwinder_type {
17	UNWINDER_GUESS,
18	UNWINDER_PROLOGUE,
19};
20
21struct 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
30bool default_next_frame(struct unwind_state *state);
31
32void unwind_start(struct unwind_state *state,
33		  struct task_struct *task, struct pt_regs *regs);
34bool unwind_next_frame(struct unwind_state *state);
35unsigned long unwind_get_return_address(struct unwind_state *state);
36
37static inline bool unwind_done(struct unwind_state *state)
38{
39	return state->stack_info.type == STACK_TYPE_UNKNOWN;
40}
41
42static 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
49static 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
56static __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
78static __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 */

 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
16enum unwinder_type {
17	UNWINDER_GUESS,
18	UNWINDER_PROLOGUE,
19};
20
21struct 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
30bool default_next_frame(struct unwind_state *state);
31
32void unwind_start(struct unwind_state *state,
33		  struct task_struct *task, struct pt_regs *regs);
34bool unwind_next_frame(struct unwind_state *state);
35unsigned long unwind_get_return_address(struct unwind_state *state);
36
37static inline bool unwind_done(struct unwind_state *state)
38{
39	return state->stack_info.type == STACK_TYPE_UNKNOWN;
40}
41
42static 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
49static 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
56static __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
78static __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 */