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1da177e4 LT |
1 | #ifndef _LINUX_FUTEX_H |
2 | #define _LINUX_FUTEX_H | |
3 | ||
286100a6 AD |
4 | #include <linux/compiler.h> |
5 | #include <linux/types.h> | |
0771dfef | 6 | |
286100a6 AD |
7 | struct inode; |
8 | struct mm_struct; | |
9 | struct task_struct; | |
c19384b5 PP |
10 | union ktime; |
11 | ||
1da177e4 LT |
12 | /* Second argument to futex syscall */ |
13 | ||
14 | ||
4732efbe JJ |
15 | #define FUTEX_WAIT 0 |
16 | #define FUTEX_WAKE 1 | |
17 | #define FUTEX_FD 2 | |
18 | #define FUTEX_REQUEUE 3 | |
19 | #define FUTEX_CMP_REQUEUE 4 | |
20 | #define FUTEX_WAKE_OP 5 | |
c87e2837 IM |
21 | #define FUTEX_LOCK_PI 6 |
22 | #define FUTEX_UNLOCK_PI 7 | |
23 | #define FUTEX_TRYLOCK_PI 8 | |
cd689985 TG |
24 | #define FUTEX_WAIT_BITSET 9 |
25 | #define FUTEX_WAKE_BITSET 10 | |
1da177e4 | 26 | |
34f01cc1 | 27 | #define FUTEX_PRIVATE_FLAG 128 |
1acdac10 TG |
28 | #define FUTEX_CLOCK_REALTIME 256 |
29 | #define FUTEX_CMD_MASK ~(FUTEX_PRIVATE_FLAG | FUTEX_CLOCK_REALTIME) | |
34f01cc1 ED |
30 | |
31 | #define FUTEX_WAIT_PRIVATE (FUTEX_WAIT | FUTEX_PRIVATE_FLAG) | |
32 | #define FUTEX_WAKE_PRIVATE (FUTEX_WAKE | FUTEX_PRIVATE_FLAG) | |
33 | #define FUTEX_REQUEUE_PRIVATE (FUTEX_REQUEUE | FUTEX_PRIVATE_FLAG) | |
34 | #define FUTEX_CMP_REQUEUE_PRIVATE (FUTEX_CMP_REQUEUE | FUTEX_PRIVATE_FLAG) | |
35 | #define FUTEX_WAKE_OP_PRIVATE (FUTEX_WAKE_OP | FUTEX_PRIVATE_FLAG) | |
36 | #define FUTEX_LOCK_PI_PRIVATE (FUTEX_LOCK_PI | FUTEX_PRIVATE_FLAG) | |
37 | #define FUTEX_UNLOCK_PI_PRIVATE (FUTEX_UNLOCK_PI | FUTEX_PRIVATE_FLAG) | |
38 | #define FUTEX_TRYLOCK_PI_PRIVATE (FUTEX_TRYLOCK_PI | FUTEX_PRIVATE_FLAG) | |
cd689985 TG |
39 | #define FUTEX_WAIT_BITSET_PRIVATE (FUTEX_WAIT_BITS | FUTEX_PRIVATE_FLAG) |
40 | #define FUTEX_WAKE_BITSET_PRIVATE (FUTEX_WAKE_BITS | FUTEX_PRIVATE_FLAG) | |
34f01cc1 | 41 | |
0771dfef IM |
42 | /* |
43 | * Support for robust futexes: the kernel cleans up held futexes at | |
44 | * thread exit time. | |
45 | */ | |
46 | ||
47 | /* | |
48 | * Per-lock list entry - embedded in user-space locks, somewhere close | |
49 | * to the futex field. (Note: user-space uses a double-linked list to | |
50 | * achieve O(1) list add and remove, but the kernel only needs to know | |
51 | * about the forward link) | |
52 | * | |
53 | * NOTE: this structure is part of the syscall ABI, and must not be | |
54 | * changed. | |
55 | */ | |
56 | struct robust_list { | |
57 | struct robust_list __user *next; | |
58 | }; | |
59 | ||
60 | /* | |
61 | * Per-thread list head: | |
62 | * | |
63 | * NOTE: this structure is part of the syscall ABI, and must only be | |
64 | * changed if the change is first communicated with the glibc folks. | |
65 | * (When an incompatible change is done, we'll increase the structure | |
66 | * size, which glibc will detect) | |
67 | */ | |
68 | struct robust_list_head { | |
69 | /* | |
70 | * The head of the list. Points back to itself if empty: | |
71 | */ | |
72 | struct robust_list list; | |
73 | ||
74 | /* | |
75 | * This relative offset is set by user-space, it gives the kernel | |
76 | * the relative position of the futex field to examine. This way | |
77 | * we keep userspace flexible, to freely shape its data-structure, | |
78 | * without hardcoding any particular offset into the kernel: | |
79 | */ | |
80 | long futex_offset; | |
81 | ||
82 | /* | |
83 | * The death of the thread may race with userspace setting | |
84 | * up a lock's links. So to handle this race, userspace first | |
85 | * sets this field to the address of the to-be-taken lock, | |
86 | * then does the lock acquire, and then adds itself to the | |
87 | * list, and then clears this field. Hence the kernel will | |
88 | * always have full knowledge of all locks that the thread | |
89 | * _might_ have taken. We check the owner TID in any case, | |
90 | * so only truly owned locks will be handled. | |
91 | */ | |
92 | struct robust_list __user *list_op_pending; | |
93 | }; | |
94 | ||
95 | /* | |
96 | * Are there any waiters for this robust futex: | |
97 | */ | |
98 | #define FUTEX_WAITERS 0x80000000 | |
99 | ||
100 | /* | |
101 | * The kernel signals via this bit that a thread holding a futex | |
102 | * has exited without unlocking the futex. The kernel also does | |
103 | * a FUTEX_WAKE on such futexes, after setting the bit, to wake | |
104 | * up any possible waiters: | |
105 | */ | |
106 | #define FUTEX_OWNER_DIED 0x40000000 | |
107 | ||
0771dfef IM |
108 | /* |
109 | * The rest of the robust-futex field is for the TID: | |
110 | */ | |
bd197234 | 111 | #define FUTEX_TID_MASK 0x3fffffff |
0771dfef IM |
112 | |
113 | /* | |
76b81e2b IM |
114 | * This limit protects against a deliberately circular list. |
115 | * (Not worth introducing an rlimit for it) | |
0771dfef | 116 | */ |
76b81e2b | 117 | #define ROBUST_LIST_LIMIT 2048 |
0771dfef | 118 | |
cd689985 TG |
119 | /* |
120 | * bitset with all bits set for the FUTEX_xxx_BITSET OPs to request a | |
121 | * match of any bit. | |
122 | */ | |
123 | #define FUTEX_BITSET_MATCH_ANY 0xffffffff | |
124 | ||
58f64d83 | 125 | #ifdef __KERNEL__ |
c19384b5 | 126 | long do_futex(u32 __user *uaddr, int op, u32 val, union ktime *timeout, |
e2970f2f | 127 | u32 __user *uaddr2, u32 val2, u32 val3); |
1da177e4 | 128 | |
e3f2ddea IM |
129 | extern int |
130 | handle_futex_death(u32 __user *uaddr, struct task_struct *curr, int pi); | |
0771dfef | 131 | |
9adef58b RR |
132 | /* |
133 | * Futexes are matched on equal values of this key. | |
134 | * The key type depends on whether it's a shared or private mapping. | |
135 | * Don't rearrange members without looking at hash_futex(). | |
136 | * | |
137 | * offset is aligned to a multiple of sizeof(u32) (== 4) by definition. | |
34f01cc1 ED |
138 | * We use the two low order bits of offset to tell what is the kind of key : |
139 | * 00 : Private process futex (PTHREAD_PROCESS_PRIVATE) | |
140 | * (no reference on an inode or mm) | |
141 | * 01 : Shared futex (PTHREAD_PROCESS_SHARED) | |
142 | * mapped on a file (reference on the underlying inode) | |
143 | * 10 : Shared futex (PTHREAD_PROCESS_SHARED) | |
144 | * (but private mapping on an mm, and reference taken on it) | |
145 | */ | |
146 | ||
147 | #define FUT_OFF_INODE 1 /* We set bit 0 if key has a reference on inode */ | |
148 | #define FUT_OFF_MMSHARED 2 /* We set bit 1 if key has a reference on mm */ | |
149 | ||
9adef58b RR |
150 | union futex_key { |
151 | struct { | |
152 | unsigned long pgoff; | |
153 | struct inode *inode; | |
154 | int offset; | |
155 | } shared; | |
156 | struct { | |
157 | unsigned long address; | |
158 | struct mm_struct *mm; | |
159 | int offset; | |
160 | } private; | |
161 | struct { | |
162 | unsigned long word; | |
163 | void *ptr; | |
164 | int offset; | |
165 | } both; | |
166 | }; | |
9adef58b | 167 | |
38d47c1b PZ |
168 | #define FUTEX_KEY_INIT (union futex_key) { .both = { .ptr = NULL } } |
169 | ||
0771dfef IM |
170 | #ifdef CONFIG_FUTEX |
171 | extern void exit_robust_list(struct task_struct *curr); | |
c87e2837 | 172 | extern void exit_pi_state_list(struct task_struct *curr); |
a0c1e907 | 173 | extern int futex_cmpxchg_enabled; |
0771dfef IM |
174 | #else |
175 | static inline void exit_robust_list(struct task_struct *curr) | |
176 | { | |
177 | } | |
c87e2837 IM |
178 | static inline void exit_pi_state_list(struct task_struct *curr) |
179 | { | |
180 | } | |
0771dfef | 181 | #endif |
58f64d83 | 182 | #endif /* __KERNEL__ */ |
0771dfef | 183 | |
4732efbe JJ |
184 | #define FUTEX_OP_SET 0 /* *(int *)UADDR2 = OPARG; */ |
185 | #define FUTEX_OP_ADD 1 /* *(int *)UADDR2 += OPARG; */ | |
186 | #define FUTEX_OP_OR 2 /* *(int *)UADDR2 |= OPARG; */ | |
187 | #define FUTEX_OP_ANDN 3 /* *(int *)UADDR2 &= ~OPARG; */ | |
188 | #define FUTEX_OP_XOR 4 /* *(int *)UADDR2 ^= OPARG; */ | |
189 | ||
190 | #define FUTEX_OP_OPARG_SHIFT 8 /* Use (1 << OPARG) instead of OPARG. */ | |
191 | ||
192 | #define FUTEX_OP_CMP_EQ 0 /* if (oldval == CMPARG) wake */ | |
193 | #define FUTEX_OP_CMP_NE 1 /* if (oldval != CMPARG) wake */ | |
194 | #define FUTEX_OP_CMP_LT 2 /* if (oldval < CMPARG) wake */ | |
195 | #define FUTEX_OP_CMP_LE 3 /* if (oldval <= CMPARG) wake */ | |
196 | #define FUTEX_OP_CMP_GT 4 /* if (oldval > CMPARG) wake */ | |
197 | #define FUTEX_OP_CMP_GE 5 /* if (oldval >= CMPARG) wake */ | |
198 | ||
199 | /* FUTEX_WAKE_OP will perform atomically | |
200 | int oldval = *(int *)UADDR2; | |
201 | *(int *)UADDR2 = oldval OP OPARG; | |
202 | if (oldval CMP CMPARG) | |
203 | wake UADDR2; */ | |
204 | ||
205 | #define FUTEX_OP(op, oparg, cmp, cmparg) \ | |
206 | (((op & 0xf) << 28) | ((cmp & 0xf) << 24) \ | |
207 | | ((oparg & 0xfff) << 12) | (cmparg & 0xfff)) | |
208 | ||
1da177e4 | 209 | #endif |