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6f52b16c | 1 | /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ |
607ca46e DH |
2 | #ifndef _UAPI_LINUX_FUTEX_H |
3 | #define _UAPI_LINUX_FUTEX_H | |
4 | ||
5 | #include <linux/compiler.h> | |
6 | #include <linux/types.h> | |
7 | ||
8 | /* Second argument to futex syscall */ | |
9 | ||
10 | ||
11 | #define FUTEX_WAIT 0 | |
12 | #define FUTEX_WAKE 1 | |
13 | #define FUTEX_FD 2 | |
14 | #define FUTEX_REQUEUE 3 | |
15 | #define FUTEX_CMP_REQUEUE 4 | |
16 | #define FUTEX_WAKE_OP 5 | |
17 | #define FUTEX_LOCK_PI 6 | |
18 | #define FUTEX_UNLOCK_PI 7 | |
19 | #define FUTEX_TRYLOCK_PI 8 | |
20 | #define FUTEX_WAIT_BITSET 9 | |
21 | #define FUTEX_WAKE_BITSET 10 | |
22 | #define FUTEX_WAIT_REQUEUE_PI 11 | |
23 | #define FUTEX_CMP_REQUEUE_PI 12 | |
bf22a697 | 24 | #define FUTEX_LOCK_PI2 13 |
607ca46e DH |
25 | |
26 | #define FUTEX_PRIVATE_FLAG 128 | |
27 | #define FUTEX_CLOCK_REALTIME 256 | |
28 | #define FUTEX_CMD_MASK ~(FUTEX_PRIVATE_FLAG | FUTEX_CLOCK_REALTIME) | |
29 | ||
30 | #define FUTEX_WAIT_PRIVATE (FUTEX_WAIT | FUTEX_PRIVATE_FLAG) | |
31 | #define FUTEX_WAKE_PRIVATE (FUTEX_WAKE | FUTEX_PRIVATE_FLAG) | |
32 | #define FUTEX_REQUEUE_PRIVATE (FUTEX_REQUEUE | FUTEX_PRIVATE_FLAG) | |
33 | #define FUTEX_CMP_REQUEUE_PRIVATE (FUTEX_CMP_REQUEUE | FUTEX_PRIVATE_FLAG) | |
34 | #define FUTEX_WAKE_OP_PRIVATE (FUTEX_WAKE_OP | FUTEX_PRIVATE_FLAG) | |
35 | #define FUTEX_LOCK_PI_PRIVATE (FUTEX_LOCK_PI | FUTEX_PRIVATE_FLAG) | |
bf22a697 | 36 | #define FUTEX_LOCK_PI2_PRIVATE (FUTEX_LOCK_PI2 | FUTEX_PRIVATE_FLAG) |
607ca46e DH |
37 | #define FUTEX_UNLOCK_PI_PRIVATE (FUTEX_UNLOCK_PI | FUTEX_PRIVATE_FLAG) |
38 | #define FUTEX_TRYLOCK_PI_PRIVATE (FUTEX_TRYLOCK_PI | FUTEX_PRIVATE_FLAG) | |
39 | #define FUTEX_WAIT_BITSET_PRIVATE (FUTEX_WAIT_BITSET | FUTEX_PRIVATE_FLAG) | |
40 | #define FUTEX_WAKE_BITSET_PRIVATE (FUTEX_WAKE_BITSET | FUTEX_PRIVATE_FLAG) | |
41 | #define FUTEX_WAIT_REQUEUE_PI_PRIVATE (FUTEX_WAIT_REQUEUE_PI | \ | |
42 | FUTEX_PRIVATE_FLAG) | |
43 | #define FUTEX_CMP_REQUEUE_PI_PRIVATE (FUTEX_CMP_REQUEUE_PI | \ | |
44 | FUTEX_PRIVATE_FLAG) | |
45 | ||
bf69bad3 AA |
46 | /* |
47 | * Flags to specify the bit length of the futex word for futex2 syscalls. | |
48 | * Currently, only 32 is supported. | |
49 | */ | |
50 | #define FUTEX_32 2 | |
51 | ||
52 | /* | |
53 | * Max numbers of elements in a futex_waitv array | |
54 | */ | |
55 | #define FUTEX_WAITV_MAX 128 | |
56 | ||
57 | /** | |
58 | * struct futex_waitv - A waiter for vectorized wait | |
59 | * @val: Expected value at uaddr | |
60 | * @uaddr: User address to wait on | |
61 | * @flags: Flags for this waiter | |
62 | * @__reserved: Reserved member to preserve data alignment. Should be 0. | |
63 | */ | |
64 | struct futex_waitv { | |
65 | __u64 val; | |
66 | __u64 uaddr; | |
67 | __u32 flags; | |
68 | __u32 __reserved; | |
69 | }; | |
70 | ||
607ca46e DH |
71 | /* |
72 | * Support for robust futexes: the kernel cleans up held futexes at | |
73 | * thread exit time. | |
74 | */ | |
75 | ||
76 | /* | |
77 | * Per-lock list entry - embedded in user-space locks, somewhere close | |
78 | * to the futex field. (Note: user-space uses a double-linked list to | |
79 | * achieve O(1) list add and remove, but the kernel only needs to know | |
80 | * about the forward link) | |
81 | * | |
82 | * NOTE: this structure is part of the syscall ABI, and must not be | |
83 | * changed. | |
84 | */ | |
85 | struct robust_list { | |
86 | struct robust_list __user *next; | |
87 | }; | |
88 | ||
89 | /* | |
90 | * Per-thread list head: | |
91 | * | |
92 | * NOTE: this structure is part of the syscall ABI, and must only be | |
93 | * changed if the change is first communicated with the glibc folks. | |
94 | * (When an incompatible change is done, we'll increase the structure | |
95 | * size, which glibc will detect) | |
96 | */ | |
97 | struct robust_list_head { | |
98 | /* | |
99 | * The head of the list. Points back to itself if empty: | |
100 | */ | |
101 | struct robust_list list; | |
102 | ||
103 | /* | |
104 | * This relative offset is set by user-space, it gives the kernel | |
105 | * the relative position of the futex field to examine. This way | |
106 | * we keep userspace flexible, to freely shape its data-structure, | |
107 | * without hardcoding any particular offset into the kernel: | |
108 | */ | |
109 | long futex_offset; | |
110 | ||
111 | /* | |
112 | * The death of the thread may race with userspace setting | |
113 | * up a lock's links. So to handle this race, userspace first | |
114 | * sets this field to the address of the to-be-taken lock, | |
115 | * then does the lock acquire, and then adds itself to the | |
116 | * list, and then clears this field. Hence the kernel will | |
117 | * always have full knowledge of all locks that the thread | |
118 | * _might_ have taken. We check the owner TID in any case, | |
119 | * so only truly owned locks will be handled. | |
120 | */ | |
121 | struct robust_list __user *list_op_pending; | |
122 | }; | |
123 | ||
124 | /* | |
125 | * Are there any waiters for this robust futex: | |
126 | */ | |
127 | #define FUTEX_WAITERS 0x80000000 | |
128 | ||
129 | /* | |
130 | * The kernel signals via this bit that a thread holding a futex | |
131 | * has exited without unlocking the futex. The kernel also does | |
132 | * a FUTEX_WAKE on such futexes, after setting the bit, to wake | |
133 | * up any possible waiters: | |
134 | */ | |
135 | #define FUTEX_OWNER_DIED 0x40000000 | |
136 | ||
137 | /* | |
138 | * The rest of the robust-futex field is for the TID: | |
139 | */ | |
140 | #define FUTEX_TID_MASK 0x3fffffff | |
141 | ||
142 | /* | |
143 | * This limit protects against a deliberately circular list. | |
144 | * (Not worth introducing an rlimit for it) | |
145 | */ | |
146 | #define ROBUST_LIST_LIMIT 2048 | |
147 | ||
148 | /* | |
149 | * bitset with all bits set for the FUTEX_xxx_BITSET OPs to request a | |
150 | * match of any bit. | |
151 | */ | |
152 | #define FUTEX_BITSET_MATCH_ANY 0xffffffff | |
153 | ||
154 | ||
155 | #define FUTEX_OP_SET 0 /* *(int *)UADDR2 = OPARG; */ | |
156 | #define FUTEX_OP_ADD 1 /* *(int *)UADDR2 += OPARG; */ | |
157 | #define FUTEX_OP_OR 2 /* *(int *)UADDR2 |= OPARG; */ | |
158 | #define FUTEX_OP_ANDN 3 /* *(int *)UADDR2 &= ~OPARG; */ | |
159 | #define FUTEX_OP_XOR 4 /* *(int *)UADDR2 ^= OPARG; */ | |
160 | ||
161 | #define FUTEX_OP_OPARG_SHIFT 8 /* Use (1 << OPARG) instead of OPARG. */ | |
162 | ||
163 | #define FUTEX_OP_CMP_EQ 0 /* if (oldval == CMPARG) wake */ | |
164 | #define FUTEX_OP_CMP_NE 1 /* if (oldval != CMPARG) wake */ | |
165 | #define FUTEX_OP_CMP_LT 2 /* if (oldval < CMPARG) wake */ | |
166 | #define FUTEX_OP_CMP_LE 3 /* if (oldval <= CMPARG) wake */ | |
167 | #define FUTEX_OP_CMP_GT 4 /* if (oldval > CMPARG) wake */ | |
168 | #define FUTEX_OP_CMP_GE 5 /* if (oldval >= CMPARG) wake */ | |
169 | ||
170 | /* FUTEX_WAKE_OP will perform atomically | |
171 | int oldval = *(int *)UADDR2; | |
172 | *(int *)UADDR2 = oldval OP OPARG; | |
173 | if (oldval CMP CMPARG) | |
174 | wake UADDR2; */ | |
175 | ||
176 | #define FUTEX_OP(op, oparg, cmp, cmparg) \ | |
177 | (((op & 0xf) << 28) | ((cmp & 0xf) << 24) \ | |
178 | | ((oparg & 0xfff) << 12) | (cmparg & 0xfff)) | |
179 | ||
180 | #endif /* _UAPI_LINUX_FUTEX_H */ |