1 /* SPDX-License-Identifier: GPL-2.0-or-later * 1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /********************************************* 2 /******************************************************************************
3 * 3 *
4 * Copyright © International Business Machi 4 * Copyright © International Business Machines Corp., 2009
5 * 5 *
6 * DESCRIPTION 6 * DESCRIPTION
7 * Glibc independent futex library for te 7 * Glibc independent futex library for testing kernel functionality.
8 * 8 *
9 * AUTHOR 9 * AUTHOR
10 * Darren Hart <dvhart@linux.intel.com> 10 * Darren Hart <dvhart@linux.intel.com>
11 * 11 *
12 * HISTORY 12 * HISTORY
13 * 2009-Nov-6: Initial version by Darren 13 * 2009-Nov-6: Initial version by Darren Hart <dvhart@linux.intel.com>
14 * 14 *
15 ********************************************* 15 *****************************************************************************/
16 16
17 #ifndef _FUTEXTEST_H 17 #ifndef _FUTEXTEST_H
18 #define _FUTEXTEST_H 18 #define _FUTEXTEST_H
19 19
20 #include <unistd.h> 20 #include <unistd.h>
21 #include <sys/syscall.h> 21 #include <sys/syscall.h>
22 #include <sys/types.h> 22 #include <sys/types.h>
23 #include <linux/futex.h> 23 #include <linux/futex.h>
24 24
25 typedef volatile u_int32_t futex_t; 25 typedef volatile u_int32_t futex_t;
26 #define FUTEX_INITIALIZER 0 26 #define FUTEX_INITIALIZER 0
27 27
28 /* Define the newer op codes if the system hea 28 /* Define the newer op codes if the system header file is not up to date. */
29 #ifndef FUTEX_WAIT_BITSET 29 #ifndef FUTEX_WAIT_BITSET
30 #define FUTEX_WAIT_BITSET 9 30 #define FUTEX_WAIT_BITSET 9
31 #endif 31 #endif
32 #ifndef FUTEX_WAKE_BITSET 32 #ifndef FUTEX_WAKE_BITSET
33 #define FUTEX_WAKE_BITSET 10 33 #define FUTEX_WAKE_BITSET 10
34 #endif 34 #endif
35 #ifndef FUTEX_WAIT_REQUEUE_PI 35 #ifndef FUTEX_WAIT_REQUEUE_PI
36 #define FUTEX_WAIT_REQUEUE_PI 11 36 #define FUTEX_WAIT_REQUEUE_PI 11
37 #endif 37 #endif
38 #ifndef FUTEX_CMP_REQUEUE_PI 38 #ifndef FUTEX_CMP_REQUEUE_PI
39 #define FUTEX_CMP_REQUEUE_PI 12 39 #define FUTEX_CMP_REQUEUE_PI 12
40 #endif 40 #endif
41 #ifndef FUTEX_WAIT_REQUEUE_PI_PRIVATE 41 #ifndef FUTEX_WAIT_REQUEUE_PI_PRIVATE
42 #define FUTEX_WAIT_REQUEUE_PI_PRIVATE (FUTEX 42 #define FUTEX_WAIT_REQUEUE_PI_PRIVATE (FUTEX_WAIT_REQUEUE_PI | \
43 FUTEX 43 FUTEX_PRIVATE_FLAG)
44 #endif 44 #endif
45 #ifndef FUTEX_REQUEUE_PI_PRIVATE 45 #ifndef FUTEX_REQUEUE_PI_PRIVATE
46 #define FUTEX_CMP_REQUEUE_PI_PRIVATE (FUTEX 46 #define FUTEX_CMP_REQUEUE_PI_PRIVATE (FUTEX_CMP_REQUEUE_PI | \
47 FUTEX 47 FUTEX_PRIVATE_FLAG)
48 #endif 48 #endif
49 49
50 /** 50 /**
51 * futex() - SYS_futex syscall wrapper 51 * futex() - SYS_futex syscall wrapper
52 * @uaddr: address of first futex 52 * @uaddr: address of first futex
53 * @op: futex op code 53 * @op: futex op code
54 * @val: typically expected value of ua 54 * @val: typically expected value of uaddr, but varies by op
55 * @timeout: typically an absolute struct t 55 * @timeout: typically an absolute struct timespec (except where noted
56 * otherwise). Overloaded by some 56 * otherwise). Overloaded by some ops
57 * @uaddr2: address of second futex for so 57 * @uaddr2: address of second futex for some ops\
58 * @val3: varies by op 58 * @val3: varies by op
59 * @opflags: flags to be bitwise OR'd with 59 * @opflags: flags to be bitwise OR'd with op, such as FUTEX_PRIVATE_FLAG
60 * 60 *
61 * futex() is used by all the following futex 61 * futex() is used by all the following futex op wrappers. It can also be
62 * used for misuse and abuse testing. Generall 62 * used for misuse and abuse testing. Generally, the specific op wrappers
63 * should be used instead. It is a macro inste 63 * should be used instead. It is a macro instead of an static inline function as
64 * some of the types over overloaded (timeout 64 * some of the types over overloaded (timeout is used for nr_requeue for
65 * example). 65 * example).
66 * 66 *
67 * These argument descriptions are the default 67 * These argument descriptions are the defaults for all
68 * like-named arguments in the following wrapp 68 * like-named arguments in the following wrappers except where noted below.
69 */ 69 */
70 #define futex(uaddr, op, val, timeout, uaddr2, 70 #define futex(uaddr, op, val, timeout, uaddr2, val3, opflags) \
71 syscall(SYS_futex, uaddr, op | opflags 71 syscall(SYS_futex, uaddr, op | opflags, val, timeout, uaddr2, val3)
72 72
73 /** 73 /**
74 * futex_wait() - block on uaddr with optional 74 * futex_wait() - block on uaddr with optional timeout
75 * @timeout: relative timeout 75 * @timeout: relative timeout
76 */ 76 */
77 static inline int 77 static inline int
78 futex_wait(futex_t *uaddr, futex_t val, struct 78 futex_wait(futex_t *uaddr, futex_t val, struct timespec *timeout, int opflags)
79 { 79 {
80 return futex(uaddr, FUTEX_WAIT, val, t 80 return futex(uaddr, FUTEX_WAIT, val, timeout, NULL, 0, opflags);
81 } 81 }
82 82
83 /** 83 /**
84 * futex_wake() - wake one or more tasks block 84 * futex_wake() - wake one or more tasks blocked on uaddr
85 * @nr_wake: wake up to this many tasks 85 * @nr_wake: wake up to this many tasks
86 */ 86 */
87 static inline int 87 static inline int
88 futex_wake(futex_t *uaddr, int nr_wake, int op 88 futex_wake(futex_t *uaddr, int nr_wake, int opflags)
89 { 89 {
90 return futex(uaddr, FUTEX_WAKE, nr_wak 90 return futex(uaddr, FUTEX_WAKE, nr_wake, NULL, NULL, 0, opflags);
91 } 91 }
92 92
93 /** 93 /**
94 * futex_wait_bitset() - block on uaddr with b 94 * futex_wait_bitset() - block on uaddr with bitset
95 * @bitset: bitset to be used with futex_w 95 * @bitset: bitset to be used with futex_wake_bitset
96 */ 96 */
97 static inline int 97 static inline int
98 futex_wait_bitset(futex_t *uaddr, futex_t val, 98 futex_wait_bitset(futex_t *uaddr, futex_t val, struct timespec *timeout,
99 u_int32_t bitset, int opflag 99 u_int32_t bitset, int opflags)
100 { 100 {
101 return futex(uaddr, FUTEX_WAIT_BITSET, 101 return futex(uaddr, FUTEX_WAIT_BITSET, val, timeout, NULL, bitset,
102 opflags); 102 opflags);
103 } 103 }
104 104
105 /** 105 /**
106 * futex_wake_bitset() - wake one or more task 106 * futex_wake_bitset() - wake one or more tasks blocked on uaddr with bitset
107 * @bitset: bitset to compare with that us 107 * @bitset: bitset to compare with that used in futex_wait_bitset
108 */ 108 */
109 static inline int 109 static inline int
110 futex_wake_bitset(futex_t *uaddr, int nr_wake, 110 futex_wake_bitset(futex_t *uaddr, int nr_wake, u_int32_t bitset, int opflags)
111 { 111 {
112 return futex(uaddr, FUTEX_WAKE_BITSET, 112 return futex(uaddr, FUTEX_WAKE_BITSET, nr_wake, NULL, NULL, bitset,
113 opflags); 113 opflags);
114 } 114 }
115 115
116 /** 116 /**
117 * futex_lock_pi() - block on uaddr as a PI mu 117 * futex_lock_pi() - block on uaddr as a PI mutex
118 * @detect: whether (1) or not (0) to perf 118 * @detect: whether (1) or not (0) to perform deadlock detection
119 */ 119 */
120 static inline int 120 static inline int
121 futex_lock_pi(futex_t *uaddr, struct timespec 121 futex_lock_pi(futex_t *uaddr, struct timespec *timeout, int detect,
122 int opflags) 122 int opflags)
123 { 123 {
124 return futex(uaddr, FUTEX_LOCK_PI, det 124 return futex(uaddr, FUTEX_LOCK_PI, detect, timeout, NULL, 0, opflags);
125 } 125 }
126 126
127 /** 127 /**
128 * futex_unlock_pi() - release uaddr as a PI m 128 * futex_unlock_pi() - release uaddr as a PI mutex, waking the top waiter
129 */ 129 */
130 static inline int 130 static inline int
131 futex_unlock_pi(futex_t *uaddr, int opflags) 131 futex_unlock_pi(futex_t *uaddr, int opflags)
132 { 132 {
133 return futex(uaddr, FUTEX_UNLOCK_PI, 0 133 return futex(uaddr, FUTEX_UNLOCK_PI, 0, NULL, NULL, 0, opflags);
134 } 134 }
135 135
136 /** 136 /**
137 * futex_wake_op() - FIXME: COME UP WITH A GOO 137 * futex_wake_op() - FIXME: COME UP WITH A GOOD ONE LINE DESCRIPTION
138 */ 138 */
139 static inline int 139 static inline int
140 futex_wake_op(futex_t *uaddr, futex_t *uaddr2, 140 futex_wake_op(futex_t *uaddr, futex_t *uaddr2, int nr_wake, int nr_wake2,
141 int wake_op, int opflags) 141 int wake_op, int opflags)
142 { 142 {
143 return futex(uaddr, FUTEX_WAKE_OP, nr_ 143 return futex(uaddr, FUTEX_WAKE_OP, nr_wake, nr_wake2, uaddr2, wake_op,
144 opflags); 144 opflags);
145 } 145 }
146 146
147 /** 147 /**
148 * futex_requeue() - requeue without expected 148 * futex_requeue() - requeue without expected value comparison, deprecated
149 * @nr_wake: wake up to this many tasks 149 * @nr_wake: wake up to this many tasks
150 * @nr_requeue: requeue up to this many tasks 150 * @nr_requeue: requeue up to this many tasks
151 * 151 *
152 * Due to its inherently racy implementation, 152 * Due to its inherently racy implementation, futex_requeue() is deprecated in
153 * favor of futex_cmp_requeue(). 153 * favor of futex_cmp_requeue().
154 */ 154 */
155 static inline int 155 static inline int
156 futex_requeue(futex_t *uaddr, futex_t *uaddr2, 156 futex_requeue(futex_t *uaddr, futex_t *uaddr2, int nr_wake, int nr_requeue,
157 int opflags) 157 int opflags)
158 { 158 {
159 return futex(uaddr, FUTEX_REQUEUE, nr_ 159 return futex(uaddr, FUTEX_REQUEUE, nr_wake, nr_requeue, uaddr2, 0,
160 opflags); 160 opflags);
161 } 161 }
162 162
163 /** 163 /**
164 * futex_cmp_requeue() - requeue tasks from ua 164 * futex_cmp_requeue() - requeue tasks from uaddr to uaddr2
165 * @nr_wake: wake up to this many tasks 165 * @nr_wake: wake up to this many tasks
166 * @nr_requeue: requeue up to this many tasks 166 * @nr_requeue: requeue up to this many tasks
167 */ 167 */
168 static inline int 168 static inline int
169 futex_cmp_requeue(futex_t *uaddr, futex_t val, 169 futex_cmp_requeue(futex_t *uaddr, futex_t val, futex_t *uaddr2, int nr_wake,
170 int nr_requeue, int opflags) 170 int nr_requeue, int opflags)
171 { 171 {
172 return futex(uaddr, FUTEX_CMP_REQUEUE, 172 return futex(uaddr, FUTEX_CMP_REQUEUE, nr_wake, nr_requeue, uaddr2,
173 val, opflags); 173 val, opflags);
174 } 174 }
175 175
176 /** 176 /**
177 * futex_wait_requeue_pi() - block on uaddr an 177 * futex_wait_requeue_pi() - block on uaddr and prepare to requeue to uaddr2
178 * @uaddr: non-PI futex source 178 * @uaddr: non-PI futex source
179 * @uaddr2: PI futex target 179 * @uaddr2: PI futex target
180 * 180 *
181 * This is the first half of the requeue_pi me 181 * This is the first half of the requeue_pi mechanism. It shall always be
182 * paired with futex_cmp_requeue_pi(). 182 * paired with futex_cmp_requeue_pi().
183 */ 183 */
184 static inline int 184 static inline int
185 futex_wait_requeue_pi(futex_t *uaddr, futex_t 185 futex_wait_requeue_pi(futex_t *uaddr, futex_t val, futex_t *uaddr2,
186 struct timespec *timeout 186 struct timespec *timeout, int opflags)
187 { 187 {
188 return futex(uaddr, FUTEX_WAIT_REQUEUE 188 return futex(uaddr, FUTEX_WAIT_REQUEUE_PI, val, timeout, uaddr2, 0,
189 opflags); 189 opflags);
190 } 190 }
191 191
192 /** 192 /**
193 * futex_cmp_requeue_pi() - requeue tasks from 193 * futex_cmp_requeue_pi() - requeue tasks from uaddr to uaddr2 (PI aware)
194 * @uaddr: non-PI futex source 194 * @uaddr: non-PI futex source
195 * @uaddr2: PI futex target 195 * @uaddr2: PI futex target
196 * @nr_wake: wake up to this many tasks 196 * @nr_wake: wake up to this many tasks
197 * @nr_requeue: requeue up to this many tasks 197 * @nr_requeue: requeue up to this many tasks
198 */ 198 */
199 static inline int 199 static inline int
200 futex_cmp_requeue_pi(futex_t *uaddr, futex_t v 200 futex_cmp_requeue_pi(futex_t *uaddr, futex_t val, futex_t *uaddr2, int nr_wake,
201 int nr_requeue, int opfla 201 int nr_requeue, int opflags)
202 { 202 {
203 return futex(uaddr, FUTEX_CMP_REQUEUE_ 203 return futex(uaddr, FUTEX_CMP_REQUEUE_PI, nr_wake, nr_requeue, uaddr2,
204 val, opflags); 204 val, opflags);
205 } 205 }
206 206
207 /** 207 /**
208 * futex_cmpxchg() - atomic compare and exchan 208 * futex_cmpxchg() - atomic compare and exchange
209 * @uaddr: The address of the futex to be 209 * @uaddr: The address of the futex to be modified
210 * @oldval: The expected value of the fute 210 * @oldval: The expected value of the futex
211 * @newval: The new value to try and assig 211 * @newval: The new value to try and assign the futex
212 * 212 *
213 * Implement cmpxchg using gcc atomic builtins 213 * Implement cmpxchg using gcc atomic builtins.
214 * http://gcc.gnu.org/onlinedocs/gcc-4.1.0/gcc 214 * http://gcc.gnu.org/onlinedocs/gcc-4.1.0/gcc/Atomic-Builtins.html
215 * 215 *
216 * Return the old futex value. 216 * Return the old futex value.
217 */ 217 */
218 static inline u_int32_t 218 static inline u_int32_t
219 futex_cmpxchg(futex_t *uaddr, u_int32_t oldval 219 futex_cmpxchg(futex_t *uaddr, u_int32_t oldval, u_int32_t newval)
220 { 220 {
221 return __sync_val_compare_and_swap(uad 221 return __sync_val_compare_and_swap(uaddr, oldval, newval);
222 } 222 }
223 223
224 /** 224 /**
225 * futex_dec() - atomic decrement of the futex 225 * futex_dec() - atomic decrement of the futex value
226 * @uaddr: The address of the futex to be 226 * @uaddr: The address of the futex to be modified
227 * 227 *
228 * Return the new futex value. 228 * Return the new futex value.
229 */ 229 */
230 static inline u_int32_t 230 static inline u_int32_t
231 futex_dec(futex_t *uaddr) 231 futex_dec(futex_t *uaddr)
232 { 232 {
233 return __sync_sub_and_fetch(uaddr, 1); 233 return __sync_sub_and_fetch(uaddr, 1);
234 } 234 }
235 235
236 /** 236 /**
237 * futex_inc() - atomic increment of the futex 237 * futex_inc() - atomic increment of the futex value
238 * @uaddr: the address of the futex to be 238 * @uaddr: the address of the futex to be modified
239 * 239 *
240 * Return the new futex value. 240 * Return the new futex value.
241 */ 241 */
242 static inline u_int32_t 242 static inline u_int32_t
243 futex_inc(futex_t *uaddr) 243 futex_inc(futex_t *uaddr)
244 { 244 {
245 return __sync_add_and_fetch(uaddr, 1); 245 return __sync_add_and_fetch(uaddr, 1);
246 } 246 }
247 247
248 /** 248 /**
249 * futex_set() - atomic decrement of the futex 249 * futex_set() - atomic decrement of the futex value
250 * @uaddr: the address of the futex to be 250 * @uaddr: the address of the futex to be modified
251 * @newval: New value for the atomic_t 251 * @newval: New value for the atomic_t
252 * 252 *
253 * Return the new futex value. 253 * Return the new futex value.
254 */ 254 */
255 static inline u_int32_t 255 static inline u_int32_t
256 futex_set(futex_t *uaddr, u_int32_t newval) 256 futex_set(futex_t *uaddr, u_int32_t newval)
257 { 257 {
258 *uaddr = newval; 258 *uaddr = newval;
259 return newval; 259 return newval;
260 } 260 }
261 261
262 #endif 262 #endif
263 263
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