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1da177e4 LT |
1 | #ifndef _LINUX_FUTEX_H |
2 | #define _LINUX_FUTEX_H | |
3 | ||
0771dfef IM |
4 | #include <linux/sched.h> |
5 | ||
c19384b5 PP |
6 | union ktime; |
7 | ||
1da177e4 LT |
8 | /* Second argument to futex syscall */ |
9 | ||
10 | ||
4732efbe JJ |
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 | |
c87e2837 IM |
17 | #define FUTEX_LOCK_PI 6 |
18 | #define FUTEX_UNLOCK_PI 7 | |
19 | #define FUTEX_TRYLOCK_PI 8 | |
d0aa7a70 | 20 | #define FUTEX_CMP_REQUEUE_PI 9 |
1da177e4 | 21 | |
0771dfef IM |
22 | /* |
23 | * Support for robust futexes: the kernel cleans up held futexes at | |
24 | * thread exit time. | |
25 | */ | |
26 | ||
27 | /* | |
28 | * Per-lock list entry - embedded in user-space locks, somewhere close | |
29 | * to the futex field. (Note: user-space uses a double-linked list to | |
30 | * achieve O(1) list add and remove, but the kernel only needs to know | |
31 | * about the forward link) | |
32 | * | |
33 | * NOTE: this structure is part of the syscall ABI, and must not be | |
34 | * changed. | |
35 | */ | |
36 | struct robust_list { | |
37 | struct robust_list __user *next; | |
38 | }; | |
39 | ||
40 | /* | |
41 | * Per-thread list head: | |
42 | * | |
43 | * NOTE: this structure is part of the syscall ABI, and must only be | |
44 | * changed if the change is first communicated with the glibc folks. | |
45 | * (When an incompatible change is done, we'll increase the structure | |
46 | * size, which glibc will detect) | |
47 | */ | |
48 | struct robust_list_head { | |
49 | /* | |
50 | * The head of the list. Points back to itself if empty: | |
51 | */ | |
52 | struct robust_list list; | |
53 | ||
54 | /* | |
55 | * This relative offset is set by user-space, it gives the kernel | |
56 | * the relative position of the futex field to examine. This way | |
57 | * we keep userspace flexible, to freely shape its data-structure, | |
58 | * without hardcoding any particular offset into the kernel: | |
59 | */ | |
60 | long futex_offset; | |
61 | ||
62 | /* | |
63 | * The death of the thread may race with userspace setting | |
64 | * up a lock's links. So to handle this race, userspace first | |
65 | * sets this field to the address of the to-be-taken lock, | |
66 | * then does the lock acquire, and then adds itself to the | |
67 | * list, and then clears this field. Hence the kernel will | |
68 | * always have full knowledge of all locks that the thread | |
69 | * _might_ have taken. We check the owner TID in any case, | |
70 | * so only truly owned locks will be handled. | |
71 | */ | |
72 | struct robust_list __user *list_op_pending; | |
73 | }; | |
74 | ||
75 | /* | |
76 | * Are there any waiters for this robust futex: | |
77 | */ | |
78 | #define FUTEX_WAITERS 0x80000000 | |
79 | ||
80 | /* | |
81 | * The kernel signals via this bit that a thread holding a futex | |
82 | * has exited without unlocking the futex. The kernel also does | |
83 | * a FUTEX_WAKE on such futexes, after setting the bit, to wake | |
84 | * up any possible waiters: | |
85 | */ | |
86 | #define FUTEX_OWNER_DIED 0x40000000 | |
87 | ||
d0aa7a70 PP |
88 | /* |
89 | * Some processes have been requeued on this PI-futex | |
90 | */ | |
91 | #define FUTEX_WAITER_REQUEUED 0x20000000 | |
92 | ||
0771dfef IM |
93 | /* |
94 | * The rest of the robust-futex field is for the TID: | |
95 | */ | |
d0aa7a70 | 96 | #define FUTEX_TID_MASK 0x0fffffff |
0771dfef IM |
97 | |
98 | /* | |
76b81e2b IM |
99 | * This limit protects against a deliberately circular list. |
100 | * (Not worth introducing an rlimit for it) | |
0771dfef | 101 | */ |
76b81e2b | 102 | #define ROBUST_LIST_LIMIT 2048 |
0771dfef | 103 | |
58f64d83 | 104 | #ifdef __KERNEL__ |
c19384b5 | 105 | long do_futex(u32 __user *uaddr, int op, u32 val, union ktime *timeout, |
e2970f2f | 106 | u32 __user *uaddr2, u32 val2, u32 val3); |
1da177e4 | 107 | |
e3f2ddea IM |
108 | extern int |
109 | handle_futex_death(u32 __user *uaddr, struct task_struct *curr, int pi); | |
0771dfef | 110 | |
9adef58b RR |
111 | /* |
112 | * Futexes are matched on equal values of this key. | |
113 | * The key type depends on whether it's a shared or private mapping. | |
114 | * Don't rearrange members without looking at hash_futex(). | |
115 | * | |
116 | * offset is aligned to a multiple of sizeof(u32) (== 4) by definition. | |
117 | * We set bit 0 to indicate if it's an inode-based key. | |
118 | */ | |
119 | union futex_key { | |
d0aa7a70 | 120 | u32 __user *uaddr; |
9adef58b RR |
121 | struct { |
122 | unsigned long pgoff; | |
123 | struct inode *inode; | |
124 | int offset; | |
125 | } shared; | |
126 | struct { | |
127 | unsigned long address; | |
128 | struct mm_struct *mm; | |
129 | int offset; | |
130 | } private; | |
131 | struct { | |
132 | unsigned long word; | |
133 | void *ptr; | |
134 | int offset; | |
135 | } both; | |
136 | }; | |
137 | int get_futex_key(u32 __user *uaddr, union futex_key *key); | |
138 | void get_futex_key_refs(union futex_key *key); | |
139 | void drop_futex_key_refs(union futex_key *key); | |
140 | ||
0771dfef IM |
141 | #ifdef CONFIG_FUTEX |
142 | extern void exit_robust_list(struct task_struct *curr); | |
c87e2837 | 143 | extern void exit_pi_state_list(struct task_struct *curr); |
0771dfef IM |
144 | #else |
145 | static inline void exit_robust_list(struct task_struct *curr) | |
146 | { | |
147 | } | |
c87e2837 IM |
148 | static inline void exit_pi_state_list(struct task_struct *curr) |
149 | { | |
150 | } | |
0771dfef | 151 | #endif |
58f64d83 | 152 | #endif /* __KERNEL__ */ |
0771dfef | 153 | |
4732efbe JJ |
154 | #define FUTEX_OP_SET 0 /* *(int *)UADDR2 = OPARG; */ |
155 | #define FUTEX_OP_ADD 1 /* *(int *)UADDR2 += OPARG; */ | |
156 | #define FUTEX_OP_OR 2 /* *(int *)UADDR2 |= OPARG; */ | |
157 | #define FUTEX_OP_ANDN 3 /* *(int *)UADDR2 &= ~OPARG; */ | |
158 | #define FUTEX_OP_XOR 4 /* *(int *)UADDR2 ^= OPARG; */ | |
159 | ||
160 | #define FUTEX_OP_OPARG_SHIFT 8 /* Use (1 << OPARG) instead of OPARG. */ | |
161 | ||
162 | #define FUTEX_OP_CMP_EQ 0 /* if (oldval == CMPARG) wake */ | |
163 | #define FUTEX_OP_CMP_NE 1 /* if (oldval != CMPARG) wake */ | |
164 | #define FUTEX_OP_CMP_LT 2 /* if (oldval < CMPARG) wake */ | |
165 | #define FUTEX_OP_CMP_LE 3 /* if (oldval <= CMPARG) wake */ | |
166 | #define FUTEX_OP_CMP_GT 4 /* if (oldval > CMPARG) wake */ | |
167 | #define FUTEX_OP_CMP_GE 5 /* if (oldval >= CMPARG) wake */ | |
168 | ||
169 | /* FUTEX_WAKE_OP will perform atomically | |
170 | int oldval = *(int *)UADDR2; | |
171 | *(int *)UADDR2 = oldval OP OPARG; | |
172 | if (oldval CMP CMPARG) | |
173 | wake UADDR2; */ | |
174 | ||
175 | #define FUTEX_OP(op, oparg, cmp, cmparg) \ | |
176 | (((op & 0xf) << 28) | ((cmp & 0xf) << 24) \ | |
177 | | ((oparg & 0xfff) << 12) | (cmparg & 0xfff)) | |
178 | ||
1da177e4 | 179 | #endif |