1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux 1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
2 #ifndef _UAPI_LINUX_FUTEX_H 2 #ifndef _UAPI_LINUX_FUTEX_H
3 #define _UAPI_LINUX_FUTEX_H 3 #define _UAPI_LINUX_FUTEX_H
4 4
5 #include <linux/compiler.h> 5 #include <linux/compiler.h>
6 #include <linux/types.h> 6 #include <linux/types.h>
7 7
8 /* Second argument to futex syscall */ 8 /* Second argument to futex syscall */
9 9
10 10
11 #define FUTEX_WAIT 0 11 #define FUTEX_WAIT 0
12 #define FUTEX_WAKE 1 12 #define FUTEX_WAKE 1
13 #define FUTEX_FD 2 13 #define FUTEX_FD 2
14 #define FUTEX_REQUEUE 3 14 #define FUTEX_REQUEUE 3
15 #define FUTEX_CMP_REQUEUE 4 15 #define FUTEX_CMP_REQUEUE 4
16 #define FUTEX_WAKE_OP 5 16 #define FUTEX_WAKE_OP 5
17 #define FUTEX_LOCK_PI 6 17 #define FUTEX_LOCK_PI 6
18 #define FUTEX_UNLOCK_PI 7 18 #define FUTEX_UNLOCK_PI 7
19 #define FUTEX_TRYLOCK_PI 8 19 #define FUTEX_TRYLOCK_PI 8
20 #define FUTEX_WAIT_BITSET 9 20 #define FUTEX_WAIT_BITSET 9
21 #define FUTEX_WAKE_BITSET 10 21 #define FUTEX_WAKE_BITSET 10
22 #define FUTEX_WAIT_REQUEUE_PI 11 22 #define FUTEX_WAIT_REQUEUE_PI 11
23 #define FUTEX_CMP_REQUEUE_PI 12 23 #define FUTEX_CMP_REQUEUE_PI 12
24 #define FUTEX_LOCK_PI2 13 24 #define FUTEX_LOCK_PI2 13
25 25
26 #define FUTEX_PRIVATE_FLAG 128 26 #define FUTEX_PRIVATE_FLAG 128
27 #define FUTEX_CLOCK_REALTIME 256 27 #define FUTEX_CLOCK_REALTIME 256
28 #define FUTEX_CMD_MASK ~(FUTEX_PRIVAT 28 #define FUTEX_CMD_MASK ~(FUTEX_PRIVATE_FLAG | FUTEX_CLOCK_REALTIME)
29 29
30 #define FUTEX_WAIT_PRIVATE (FUTEX_WAIT | 30 #define FUTEX_WAIT_PRIVATE (FUTEX_WAIT | FUTEX_PRIVATE_FLAG)
31 #define FUTEX_WAKE_PRIVATE (FUTEX_WAKE | 31 #define FUTEX_WAKE_PRIVATE (FUTEX_WAKE | FUTEX_PRIVATE_FLAG)
32 #define FUTEX_REQUEUE_PRIVATE (FUTEX_REQUEUE 32 #define FUTEX_REQUEUE_PRIVATE (FUTEX_REQUEUE | FUTEX_PRIVATE_FLAG)
33 #define FUTEX_CMP_REQUEUE_PRIVATE (FUTEX_CMP_R 33 #define FUTEX_CMP_REQUEUE_PRIVATE (FUTEX_CMP_REQUEUE | FUTEX_PRIVATE_FLAG)
34 #define FUTEX_WAKE_OP_PRIVATE (FUTEX_WAKE_OP 34 #define FUTEX_WAKE_OP_PRIVATE (FUTEX_WAKE_OP | FUTEX_PRIVATE_FLAG)
35 #define FUTEX_LOCK_PI_PRIVATE (FUTEX_LOCK_PI 35 #define FUTEX_LOCK_PI_PRIVATE (FUTEX_LOCK_PI | FUTEX_PRIVATE_FLAG)
36 #define FUTEX_LOCK_PI2_PRIVATE (FUTEX_LOCK_PI 36 #define FUTEX_LOCK_PI2_PRIVATE (FUTEX_LOCK_PI2 | FUTEX_PRIVATE_FLAG)
37 #define FUTEX_UNLOCK_PI_PRIVATE (FUTEX_UNLOCK_ 37 #define FUTEX_UNLOCK_PI_PRIVATE (FUTEX_UNLOCK_PI | FUTEX_PRIVATE_FLAG)
38 #define FUTEX_TRYLOCK_PI_PRIVATE (FUTEX_TRYLOC 38 #define FUTEX_TRYLOCK_PI_PRIVATE (FUTEX_TRYLOCK_PI | FUTEX_PRIVATE_FLAG)
39 #define FUTEX_WAIT_BITSET_PRIVATE (FUTEX 39 #define FUTEX_WAIT_BITSET_PRIVATE (FUTEX_WAIT_BITSET | FUTEX_PRIVATE_FLAG)
40 #define FUTEX_WAKE_BITSET_PRIVATE (FUTEX 40 #define FUTEX_WAKE_BITSET_PRIVATE (FUTEX_WAKE_BITSET | FUTEX_PRIVATE_FLAG)
41 #define FUTEX_WAIT_REQUEUE_PI_PRIVATE (FUTEX 41 #define FUTEX_WAIT_REQUEUE_PI_PRIVATE (FUTEX_WAIT_REQUEUE_PI | \
42 FUTEX 42 FUTEX_PRIVATE_FLAG)
43 #define FUTEX_CMP_REQUEUE_PI_PRIVATE (FUTEX 43 #define FUTEX_CMP_REQUEUE_PI_PRIVATE (FUTEX_CMP_REQUEUE_PI | \
44 FUTEX 44 FUTEX_PRIVATE_FLAG)
45 45
46 /* 46 /*
47 * Flags for futex2 syscalls. !! 47 * Flags to specify the bit length of the futex word for futex2 syscalls.
48 * !! 48 * Currently, only 32 is supported.
49 * NOTE: these are not pure flags, they can al <<
50 * <<
51 * union { <<
52 * u32 flags; <<
53 * struct { <<
54 * u32 size : 2, <<
55 * numa : 1, <<
56 * : 4, <<
57 * private : 1; <<
58 * }; <<
59 * }; <<
60 */ 49 */
61 #define FUTEX2_SIZE_U8 0x00 !! 50 #define FUTEX_32 2
62 #define FUTEX2_SIZE_U16 0x01 <<
63 #define FUTEX2_SIZE_U32 0x02 <<
64 #define FUTEX2_SIZE_U64 0x03 <<
65 #define FUTEX2_NUMA 0x04 <<
66 /* 0x08 */ <<
67 /* 0x10 */ <<
68 /* 0x20 */ <<
69 /* 0x40 */ <<
70 #define FUTEX2_PRIVATE FUTEX_PRIVATE_ <<
71 <<
72 #define FUTEX2_SIZE_MASK 0x03 <<
73 <<
74 /* do not use */ <<
75 #define FUTEX_32 FUTEX2_SIZE_U3 <<
76 51
77 /* 52 /*
78 * Max numbers of elements in a futex_waitv ar 53 * Max numbers of elements in a futex_waitv array
79 */ 54 */
80 #define FUTEX_WAITV_MAX 128 55 #define FUTEX_WAITV_MAX 128
81 56
82 /** 57 /**
83 * struct futex_waitv - A waiter for vectorize 58 * struct futex_waitv - A waiter for vectorized wait
84 * @val: Expected value at uaddr 59 * @val: Expected value at uaddr
85 * @uaddr: User address to wait on 60 * @uaddr: User address to wait on
86 * @flags: Flags for this waiter 61 * @flags: Flags for this waiter
87 * @__reserved: Reserved member to preserve da 62 * @__reserved: Reserved member to preserve data alignment. Should be 0.
88 */ 63 */
89 struct futex_waitv { 64 struct futex_waitv {
90 __u64 val; 65 __u64 val;
91 __u64 uaddr; 66 __u64 uaddr;
92 __u32 flags; 67 __u32 flags;
93 __u32 __reserved; 68 __u32 __reserved;
94 }; 69 };
95 70
96 /* 71 /*
97 * Support for robust futexes: the kernel clea 72 * Support for robust futexes: the kernel cleans up held futexes at
98 * thread exit time. 73 * thread exit time.
99 */ 74 */
100 75
101 /* 76 /*
102 * Per-lock list entry - embedded in user-spac 77 * Per-lock list entry - embedded in user-space locks, somewhere close
103 * to the futex field. (Note: user-space uses 78 * to the futex field. (Note: user-space uses a double-linked list to
104 * achieve O(1) list add and remove, but the k 79 * achieve O(1) list add and remove, but the kernel only needs to know
105 * about the forward link) 80 * about the forward link)
106 * 81 *
107 * NOTE: this structure is part of the syscall 82 * NOTE: this structure is part of the syscall ABI, and must not be
108 * changed. 83 * changed.
109 */ 84 */
110 struct robust_list { 85 struct robust_list {
111 struct robust_list __user *next; 86 struct robust_list __user *next;
112 }; 87 };
113 88
114 /* 89 /*
115 * Per-thread list head: 90 * Per-thread list head:
116 * 91 *
117 * NOTE: this structure is part of the syscall 92 * NOTE: this structure is part of the syscall ABI, and must only be
118 * changed if the change is first communicated 93 * changed if the change is first communicated with the glibc folks.
119 * (When an incompatible change is done, we'll 94 * (When an incompatible change is done, we'll increase the structure
120 * size, which glibc will detect) 95 * size, which glibc will detect)
121 */ 96 */
122 struct robust_list_head { 97 struct robust_list_head {
123 /* 98 /*
124 * The head of the list. Points back t 99 * The head of the list. Points back to itself if empty:
125 */ 100 */
126 struct robust_list list; 101 struct robust_list list;
127 102
128 /* 103 /*
129 * This relative offset is set by user 104 * This relative offset is set by user-space, it gives the kernel
130 * the relative position of the futex 105 * the relative position of the futex field to examine. This way
131 * we keep userspace flexible, to free 106 * we keep userspace flexible, to freely shape its data-structure,
132 * without hardcoding any particular o 107 * without hardcoding any particular offset into the kernel:
133 */ 108 */
134 long futex_offset; 109 long futex_offset;
135 110
136 /* 111 /*
137 * The death of the thread may race wi 112 * The death of the thread may race with userspace setting
138 * up a lock's links. So to handle thi 113 * up a lock's links. So to handle this race, userspace first
139 * sets this field to the address of t 114 * sets this field to the address of the to-be-taken lock,
140 * then does the lock acquire, and the 115 * then does the lock acquire, and then adds itself to the
141 * list, and then clears this field. H 116 * list, and then clears this field. Hence the kernel will
142 * always have full knowledge of all l 117 * always have full knowledge of all locks that the thread
143 * _might_ have taken. We check the ow 118 * _might_ have taken. We check the owner TID in any case,
144 * so only truly owned locks will be h 119 * so only truly owned locks will be handled.
145 */ 120 */
146 struct robust_list __user *list_op_pen 121 struct robust_list __user *list_op_pending;
147 }; 122 };
148 123
149 /* 124 /*
150 * Are there any waiters for this robust futex 125 * Are there any waiters for this robust futex:
151 */ 126 */
152 #define FUTEX_WAITERS 0x80000000 127 #define FUTEX_WAITERS 0x80000000
153 128
154 /* 129 /*
155 * The kernel signals via this bit that a thre 130 * The kernel signals via this bit that a thread holding a futex
156 * has exited without unlocking the futex. The 131 * has exited without unlocking the futex. The kernel also does
157 * a FUTEX_WAKE on such futexes, after setting 132 * a FUTEX_WAKE on such futexes, after setting the bit, to wake
158 * up any possible waiters: 133 * up any possible waiters:
159 */ 134 */
160 #define FUTEX_OWNER_DIED 0x40000000 135 #define FUTEX_OWNER_DIED 0x40000000
161 136
162 /* 137 /*
163 * The rest of the robust-futex field is for t 138 * The rest of the robust-futex field is for the TID:
164 */ 139 */
165 #define FUTEX_TID_MASK 0x3fffffff 140 #define FUTEX_TID_MASK 0x3fffffff
166 141
167 /* 142 /*
168 * This limit protects against a deliberately 143 * This limit protects against a deliberately circular list.
169 * (Not worth introducing an rlimit for it) 144 * (Not worth introducing an rlimit for it)
170 */ 145 */
171 #define ROBUST_LIST_LIMIT 2048 146 #define ROBUST_LIST_LIMIT 2048
172 147
173 /* 148 /*
174 * bitset with all bits set for the FUTEX_xxx_ 149 * bitset with all bits set for the FUTEX_xxx_BITSET OPs to request a
175 * match of any bit. 150 * match of any bit.
176 */ 151 */
177 #define FUTEX_BITSET_MATCH_ANY 0xffffffff 152 #define FUTEX_BITSET_MATCH_ANY 0xffffffff
178 153
179 154
180 #define FUTEX_OP_SET 0 /* *(i 155 #define FUTEX_OP_SET 0 /* *(int *)UADDR2 = OPARG; */
181 #define FUTEX_OP_ADD 1 /* *(i 156 #define FUTEX_OP_ADD 1 /* *(int *)UADDR2 += OPARG; */
182 #define FUTEX_OP_OR 2 /* *(i 157 #define FUTEX_OP_OR 2 /* *(int *)UADDR2 |= OPARG; */
183 #define FUTEX_OP_ANDN 3 /* *(i 158 #define FUTEX_OP_ANDN 3 /* *(int *)UADDR2 &= ~OPARG; */
184 #define FUTEX_OP_XOR 4 /* *(i 159 #define FUTEX_OP_XOR 4 /* *(int *)UADDR2 ^= OPARG; */
185 160
186 #define FUTEX_OP_OPARG_SHIFT 8 /* Use 161 #define FUTEX_OP_OPARG_SHIFT 8 /* Use (1 << OPARG) instead of OPARG. */
187 162
188 #define FUTEX_OP_CMP_EQ 0 /* if 163 #define FUTEX_OP_CMP_EQ 0 /* if (oldval == CMPARG) wake */
189 #define FUTEX_OP_CMP_NE 1 /* if 164 #define FUTEX_OP_CMP_NE 1 /* if (oldval != CMPARG) wake */
190 #define FUTEX_OP_CMP_LT 2 /* if 165 #define FUTEX_OP_CMP_LT 2 /* if (oldval < CMPARG) wake */
191 #define FUTEX_OP_CMP_LE 3 /* if 166 #define FUTEX_OP_CMP_LE 3 /* if (oldval <= CMPARG) wake */
192 #define FUTEX_OP_CMP_GT 4 /* if 167 #define FUTEX_OP_CMP_GT 4 /* if (oldval > CMPARG) wake */
193 #define FUTEX_OP_CMP_GE 5 /* if 168 #define FUTEX_OP_CMP_GE 5 /* if (oldval >= CMPARG) wake */
194 169
195 /* FUTEX_WAKE_OP will perform atomically 170 /* FUTEX_WAKE_OP will perform atomically
196 int oldval = *(int *)UADDR2; 171 int oldval = *(int *)UADDR2;
197 *(int *)UADDR2 = oldval OP OPARG; 172 *(int *)UADDR2 = oldval OP OPARG;
198 if (oldval CMP CMPARG) 173 if (oldval CMP CMPARG)
199 wake UADDR2; */ 174 wake UADDR2; */
200 175
201 #define FUTEX_OP(op, oparg, cmp, cmparg) \ 176 #define FUTEX_OP(op, oparg, cmp, cmparg) \
202 (((op & 0xf) << 28) | ((cmp & 0xf) << 24) 177 (((op & 0xf) << 28) | ((cmp & 0xf) << 24) \
203 | ((oparg & 0xfff) << 12) | (cmparg & 0xfff 178 | ((oparg & 0xfff) << 12) | (cmparg & 0xfff))
204 179
205 #endif /* _UAPI_LINUX_FUTEX_H */ 180 #endif /* _UAPI_LINUX_FUTEX_H */
206 181
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