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1 | /* SPDX-License-Identifier: GPL-2.0-or-later WITH Linux-syscall-note */ |
2 | /* SPDX-FileCopyrightText: 2015-2022 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> */ | |
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3 | |
4 | /* | |
2d533093 | 5 | * rseq/rseq-abi.h |
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6 | * |
7 | * Restartable sequences system call API | |
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8 | */ |
9 | ||
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10 | #ifndef _RSEQ_ABI_H |
11 | #define _RSEQ_ABI_H | |
12 | ||
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13 | #include <linux/types.h> |
14 | #include <asm/byteorder.h> | |
15 | ||
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16 | enum rseq_abi_cpu_id_state { |
17 | RSEQ_ABI_CPU_ID_UNINITIALIZED = -1, | |
18 | RSEQ_ABI_CPU_ID_REGISTRATION_FAILED = -2, | |
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19 | }; |
20 | ||
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21 | enum rseq_abi_flags { |
22 | RSEQ_ABI_FLAG_UNREGISTER = (1 << 0), | |
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23 | }; |
24 | ||
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25 | enum rseq_abi_cs_flags_bit { |
26 | RSEQ_ABI_CS_FLAG_NO_RESTART_ON_PREEMPT_BIT = 0, | |
27 | RSEQ_ABI_CS_FLAG_NO_RESTART_ON_SIGNAL_BIT = 1, | |
28 | RSEQ_ABI_CS_FLAG_NO_RESTART_ON_MIGRATE_BIT = 2, | |
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29 | }; |
30 | ||
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31 | enum rseq_abi_cs_flags { |
32 | RSEQ_ABI_CS_FLAG_NO_RESTART_ON_PREEMPT = | |
33 | (1U << RSEQ_ABI_CS_FLAG_NO_RESTART_ON_PREEMPT_BIT), | |
34 | RSEQ_ABI_CS_FLAG_NO_RESTART_ON_SIGNAL = | |
35 | (1U << RSEQ_ABI_CS_FLAG_NO_RESTART_ON_SIGNAL_BIT), | |
36 | RSEQ_ABI_CS_FLAG_NO_RESTART_ON_MIGRATE = | |
37 | (1U << RSEQ_ABI_CS_FLAG_NO_RESTART_ON_MIGRATE_BIT), | |
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38 | }; |
39 | ||
40 | /* | |
2d533093 | 41 | * struct rseq_abi_cs is aligned on 4 * 8 bytes to ensure it is always |
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42 | * contained within a single cache-line. It is usually declared as |
43 | * link-time constant data. | |
44 | */ | |
2d533093 | 45 | struct rseq_abi_cs { |
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46 | /* Version of this structure. */ |
47 | __u32 version; | |
2d533093 | 48 | /* enum rseq_abi_cs_flags */ |
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49 | __u32 flags; |
50 | __u64 start_ip; | |
51 | /* Offset from start_ip. */ | |
52 | __u64 post_commit_offset; | |
53 | __u64 abort_ip; | |
54 | } __attribute__((aligned(4 * sizeof(__u64)))); | |
55 | ||
56 | /* | |
2d533093 | 57 | * struct rseq_abi is aligned on 4 * 8 bytes to ensure it is always |
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58 | * contained within a single cache-line. |
59 | * | |
2d533093 | 60 | * A single struct rseq_abi per thread is allowed. |
7fc5861f | 61 | */ |
2d533093 | 62 | struct rseq_abi { |
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63 | /* |
64 | * Restartable sequences cpu_id_start field. Updated by the | |
65 | * kernel. Read by user-space with single-copy atomicity | |
66 | * semantics. This field should only be read by the thread which | |
67 | * registered this data structure. Aligned on 32-bit. Always | |
68 | * contains a value in the range of possible CPUs, although the | |
69 | * value may not be the actual current CPU (e.g. if rseq is not | |
70 | * initialized). This CPU number value should always be compared | |
71 | * against the value of the cpu_id field before performing a rseq | |
72 | * commit or returning a value read from a data structure indexed | |
73 | * using the cpu_id_start value. | |
74 | */ | |
75 | __u32 cpu_id_start; | |
76 | /* | |
77 | * Restartable sequences cpu_id field. Updated by the kernel. | |
78 | * Read by user-space with single-copy atomicity semantics. This | |
79 | * field should only be read by the thread which registered this | |
80 | * data structure. Aligned on 32-bit. Values | |
81 | * RSEQ_CPU_ID_UNINITIALIZED and RSEQ_CPU_ID_REGISTRATION_FAILED | |
82 | * have a special semantic: the former means "rseq uninitialized", | |
83 | * and latter means "rseq initialization failed". This value is | |
84 | * meant to be read within rseq critical sections and compared | |
85 | * with the cpu_id_start value previously read, before performing | |
86 | * the commit instruction, or read and compared with the | |
87 | * cpu_id_start value before returning a value loaded from a data | |
88 | * structure indexed using the cpu_id_start value. | |
89 | */ | |
90 | __u32 cpu_id; | |
91 | /* | |
92 | * Restartable sequences rseq_cs field. | |
93 | * | |
94 | * Contains NULL when no critical section is active for the current | |
95 | * thread, or holds a pointer to the currently active struct rseq_cs. | |
96 | * | |
97 | * Updated by user-space, which sets the address of the currently | |
98 | * active rseq_cs at the beginning of assembly instruction sequence | |
99 | * block, and set to NULL by the kernel when it restarts an assembly | |
100 | * instruction sequence block, as well as when the kernel detects that | |
101 | * it is preempting or delivering a signal outside of the range | |
102 | * targeted by the rseq_cs. Also needs to be set to NULL by user-space | |
103 | * before reclaiming memory that contains the targeted struct rseq_cs. | |
104 | * | |
105 | * Read and set by the kernel. Set by user-space with single-copy | |
106 | * atomicity semantics. This field should only be updated by the | |
107 | * thread which registered this data structure. Aligned on 64-bit. | |
108 | */ | |
109 | union { | |
110 | __u64 ptr64; | |
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111 | |
112 | /* | |
113 | * The "arch" field provides architecture accessor for | |
114 | * the ptr field based on architecture pointer size and | |
115 | * endianness. | |
116 | */ | |
7fc5861f | 117 | struct { |
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118 | #ifdef __LP64__ |
119 | __u64 ptr; | |
120 | #elif defined(__BYTE_ORDER) ? (__BYTE_ORDER == __BIG_ENDIAN) : defined(__BIG_ENDIAN) | |
7fc5861f | 121 | __u32 padding; /* Initialized to zero. */ |
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122 | __u32 ptr; |
123 | #else | |
124 | __u32 ptr; | |
7fc5861f | 125 | __u32 padding; /* Initialized to zero. */ |
7fc5861f | 126 | #endif |
2d533093 | 127 | } arch; |
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128 | } rseq_cs; |
129 | ||
130 | /* | |
131 | * Restartable sequences flags field. | |
132 | * | |
133 | * This field should only be updated by the thread which | |
134 | * registered this data structure. Read by the kernel. | |
135 | * Mainly used for single-stepping through rseq critical sections | |
136 | * with debuggers. | |
137 | * | |
2d533093 | 138 | * - RSEQ_ABI_CS_FLAG_NO_RESTART_ON_PREEMPT |
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139 | * Inhibit instruction sequence block restart on preemption |
140 | * for this thread. | |
2d533093 | 141 | * - RSEQ_ABI_CS_FLAG_NO_RESTART_ON_SIGNAL |
7fc5861f MJ |
142 | * Inhibit instruction sequence block restart on signal |
143 | * delivery for this thread. | |
2d533093 | 144 | * - RSEQ_ABI_CS_FLAG_NO_RESTART_ON_MIGRATE |
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145 | * Inhibit instruction sequence block restart on migration for |
146 | * this thread. | |
147 | */ | |
148 | __u32 flags; | |
149 | } __attribute__((aligned(4 * sizeof(__u64)))); | |
150 | ||
151 | /* | |
152 | * Define the rseq system call number if not yet available in | |
153 | * the system headers. | |
154 | */ | |
155 | #ifdef __x86_64__ | |
156 | ||
157 | #ifndef __NR_rseq | |
158 | #define __NR_rseq 334 | |
159 | #endif | |
160 | ||
161 | #elif defined(__i386__) | |
162 | ||
163 | #ifndef __NR_rseq | |
164 | #define __NR_rseq 386 | |
165 | #endif | |
166 | ||
167 | #elif defined(__AARCH64EL__) | |
168 | ||
169 | #ifndef __NR_rseq | |
170 | #define __NR_rseq 293 | |
171 | #endif | |
172 | ||
173 | #elif defined(__ARMEL__) | |
174 | ||
175 | #ifndef __NR_rseq | |
176 | #define __NR_rseq 398 | |
177 | #endif | |
178 | ||
179 | #elif defined(__PPC__) | |
180 | ||
181 | #ifndef __NR_rseq | |
182 | #define __NR_rseq 387 | |
183 | #endif | |
184 | ||
185 | #elif defined(__s390__) | |
186 | ||
187 | #ifndef __NR_rseq | |
188 | #define __NR_rseq 383 | |
189 | #endif | |
190 | ||
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191 | #elif defined(__riscv) |
192 | ||
193 | #ifndef __NR_rseq | |
194 | #define __NR_rseq 293 | |
195 | #endif | |
196 | ||
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197 | #endif |
198 | ||
2d533093 | 199 | #endif /* _RSEQ_ABI_H */ |