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