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744d0b8b | 1 | /* SPDX-License-Identifier: LGPL-2.1-only OR MIT */ |
784b0012 MD |
2 | /* |
3 | * rseq.h | |
4 | * | |
5 | * (C) Copyright 2016-2018 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
6 | */ | |
7 | ||
8 | #ifndef RSEQ_H | |
9 | #define RSEQ_H | |
10 | ||
11 | #include <stdint.h> | |
12 | #include <stdbool.h> | |
13 | #include <pthread.h> | |
14 | #include <signal.h> | |
15 | #include <sched.h> | |
16 | #include <errno.h> | |
17 | #include <stdio.h> | |
18 | #include <stdlib.h> | |
19 | #include <sched.h> | |
2d533093 | 20 | #include <rseq/rseq-abi.h> |
dd76f2d6 | 21 | #include <rseq/compiler.h> |
784b0012 MD |
22 | |
23 | /* | |
24 | * Empty code injection macros, override when testing. | |
25 | * It is important to consider that the ASM injection macros need to be | |
26 | * fully reentrant (e.g. do not modify the stack). | |
27 | */ | |
28 | #ifndef RSEQ_INJECT_ASM | |
29 | #define RSEQ_INJECT_ASM(n) | |
30 | #endif | |
31 | ||
32 | #ifndef RSEQ_INJECT_C | |
33 | #define RSEQ_INJECT_C(n) | |
34 | #endif | |
35 | ||
36 | #ifndef RSEQ_INJECT_INPUT | |
37 | #define RSEQ_INJECT_INPUT | |
38 | #endif | |
39 | ||
40 | #ifndef RSEQ_INJECT_CLOBBER | |
41 | #define RSEQ_INJECT_CLOBBER | |
42 | #endif | |
43 | ||
44 | #ifndef RSEQ_INJECT_FAILED | |
45 | #define RSEQ_INJECT_FAILED | |
46 | #endif | |
47 | ||
96b6ce39 MD |
48 | |
49 | /* | |
50 | * User code can define RSEQ_GET_ABI_OVERRIDE to override the | |
51 | * rseq_get_abi() implementation, for instance to use glibc's symbols | |
52 | * directly. | |
53 | */ | |
54 | #ifndef RSEQ_GET_ABI_OVERRIDE | |
55 | ||
56 | # include <rseq/rseq-thread-pointer.h> | |
57 | ||
58 | # ifdef __cplusplus | |
60a27517 | 59 | extern "C" { |
96b6ce39 | 60 | # endif |
60a27517 | 61 | |
9698c399 MD |
62 | /* Offset from the thread pointer to the rseq area. */ |
63 | extern int rseq_offset; | |
64 | /* Size of the registered rseq area. 0 if the registration was | |
65 | unsuccessful. */ | |
66 | extern unsigned int rseq_size; | |
67 | /* Flags used during rseq registration. */ | |
68 | extern unsigned int rseq_flags; | |
784b0012 | 69 | |
2d533093 | 70 | static inline struct rseq_abi *rseq_get_abi(void) |
96b6ce39 | 71 | { |
2d533093 | 72 | return (struct rseq_abi *) ((uintptr_t) rseq_thread_pointer() + rseq_offset); |
60a27517 | 73 | } |
96b6ce39 MD |
74 | |
75 | # ifdef __cplusplus | |
76 | } | |
77 | # endif | |
78 | ||
79 | #endif /* RSEQ_GET_ABI_OVERRIDE */ | |
60a27517 | 80 | |
784b0012 MD |
81 | #define rseq_likely(x) __builtin_expect(!!(x), 1) |
82 | #define rseq_unlikely(x) __builtin_expect(!!(x), 0) | |
83 | #define rseq_barrier() __asm__ __volatile__("" : : : "memory") | |
84 | ||
85 | #define RSEQ_ACCESS_ONCE(x) (*(__volatile__ __typeof__(x) *)&(x)) | |
86 | #define RSEQ_WRITE_ONCE(x, v) __extension__ ({ RSEQ_ACCESS_ONCE(x) = (v); }) | |
87 | #define RSEQ_READ_ONCE(x) RSEQ_ACCESS_ONCE(x) | |
88 | ||
89 | #define __rseq_str_1(x) #x | |
90 | #define __rseq_str(x) __rseq_str_1(x) | |
91 | ||
92 | #define rseq_log(fmt, args...) \ | |
93 | fprintf(stderr, fmt "(in %s() at " __FILE__ ":" __rseq_str(__LINE__)"\n", \ | |
94 | ## args, __func__) | |
95 | ||
96 | #define rseq_bug(fmt, args...) \ | |
97 | do { \ | |
98 | rseq_log(fmt, ##args); \ | |
99 | abort(); \ | |
100 | } while (0) | |
101 | ||
102 | #if defined(__x86_64__) || defined(__i386__) | |
103 | #include <rseq/rseq-x86.h> | |
510fdec0 | 104 | #elif defined(__ARMEL__) || defined(__ARMEB__) |
784b0012 | 105 | #include <rseq/rseq-arm.h> |
d78a16c2 MD |
106 | #elif defined (__AARCH64EL__) |
107 | #include <rseq/rseq-arm64.h> | |
784b0012 MD |
108 | #elif defined(__PPC__) |
109 | #include <rseq/rseq-ppc.h> | |
110 | #elif defined(__mips__) | |
111 | #include <rseq/rseq-mips.h> | |
4969e3fa MD |
112 | #elif defined(__s390__) |
113 | #include <rseq/rseq-s390.h> | |
784b0012 MD |
114 | #else |
115 | #error unsupported target | |
116 | #endif | |
117 | ||
15260018 | 118 | #ifdef __cplusplus |
60a27517 MG |
119 | extern "C" { |
120 | #endif | |
121 | ||
784b0012 MD |
122 | /* |
123 | * Register rseq for the current thread. This needs to be called once | |
124 | * by any thread which uses restartable sequences, before they start | |
125 | * using restartable sequences, to ensure restartable sequences | |
126 | * succeed. A restartable sequence executed from a non-registered | |
127 | * thread will always fail. | |
128 | */ | |
129 | int rseq_register_current_thread(void); | |
130 | ||
131 | /* | |
132 | * Unregister rseq for current thread. | |
133 | */ | |
134 | int rseq_unregister_current_thread(void); | |
135 | ||
136 | /* | |
137 | * Restartable sequence fallback for reading the current CPU number. | |
138 | */ | |
139 | int32_t rseq_fallback_current_cpu(void); | |
140 | ||
52e82b87 MD |
141 | int rseq_available(void); |
142 | ||
784b0012 MD |
143 | /* |
144 | * Values returned can be either the current CPU number, -1 (rseq is | |
145 | * uninitialized), or -2 (rseq initialization has failed). | |
146 | */ | |
147 | static inline int32_t rseq_current_cpu_raw(void) | |
148 | { | |
9698c399 | 149 | return RSEQ_READ_ONCE(rseq_get_abi()->cpu_id); |
784b0012 MD |
150 | } |
151 | ||
152 | /* | |
153 | * Returns a possible CPU number, which is typically the current CPU. | |
154 | * The returned CPU number can be used to prepare for an rseq critical | |
155 | * section, which will confirm whether the cpu number is indeed the | |
156 | * current one, and whether rseq is initialized. | |
157 | * | |
158 | * The CPU number returned by rseq_cpu_start should always be validated | |
159 | * by passing it to a rseq asm sequence, or by comparing it to the | |
160 | * return value of rseq_current_cpu_raw() if the rseq asm sequence | |
161 | * does not need to be invoked. | |
162 | */ | |
163 | static inline uint32_t rseq_cpu_start(void) | |
164 | { | |
9698c399 | 165 | return RSEQ_READ_ONCE(rseq_get_abi()->cpu_id_start); |
784b0012 MD |
166 | } |
167 | ||
168 | static inline uint32_t rseq_current_cpu(void) | |
169 | { | |
170 | int32_t cpu; | |
171 | ||
172 | cpu = rseq_current_cpu_raw(); | |
173 | if (rseq_unlikely(cpu < 0)) | |
174 | cpu = rseq_fallback_current_cpu(); | |
175 | return cpu; | |
176 | } | |
177 | ||
178 | static inline void rseq_clear_rseq_cs(void) | |
179 | { | |
2d533093 | 180 | RSEQ_WRITE_ONCE(rseq_get_abi()->rseq_cs.arch.ptr, 0); |
784b0012 MD |
181 | } |
182 | ||
183 | /* | |
184 | * rseq_prepare_unload() should be invoked by each thread executing a rseq | |
185 | * critical section at least once between their last critical section and | |
186 | * library unload of the library defining the rseq critical section | |
2d533093 | 187 | * (struct rseq_ab_cs). This also applies to use of rseq in code generated by |
784b0012 MD |
188 | * JIT: rseq_prepare_unload() should be invoked at least once by each |
189 | * thread executing a rseq critical section before reclaim of the memory | |
2d533093 | 190 | * holding the struct rseq_abi_cs. |
784b0012 MD |
191 | */ |
192 | static inline void rseq_prepare_unload(void) | |
193 | { | |
194 | rseq_clear_rseq_cs(); | |
195 | } | |
196 | ||
15260018 | 197 | #ifdef __cplusplus |
60a27517 MG |
198 | } |
199 | #endif | |
200 | ||
784b0012 | 201 | #endif /* RSEQ_H_ */ |