1 | /* SPDX-License-Identifier: GPL-2.0 */ |
2 | #ifndef _LINUX_FUTEX_H |
3 | #define _LINUX_FUTEX_H |
4 | |
5 | #include <linux/sched.h> |
6 | #include <linux/ktime.h> |
7 | |
8 | #include <uapi/linux/futex.h> |
9 | |
10 | struct inode; |
11 | struct mm_struct; |
12 | struct task_struct; |
13 | |
14 | /* |
15 | * Futexes are matched on equal values of this key. |
16 | * The key type depends on whether it's a shared or private mapping. |
17 | * Don't rearrange members without looking at hash_futex(). |
18 | * |
19 | * offset is aligned to a multiple of sizeof(u32) (== 4) by definition. |
20 | * We use the two low order bits of offset to tell what is the kind of key : |
21 | * 00 : Private process futex (PTHREAD_PROCESS_PRIVATE) |
22 | * (no reference on an inode or mm) |
23 | * 01 : Shared futex (PTHREAD_PROCESS_SHARED) |
24 | * mapped on a file (reference on the underlying inode) |
25 | * 10 : Shared futex (PTHREAD_PROCESS_SHARED) |
26 | * (but private mapping on an mm, and reference taken on it) |
27 | */ |
28 | |
29 | #define FUT_OFF_INODE 1 /* We set bit 0 if key has a reference on inode */ |
30 | #define FUT_OFF_MMSHARED 2 /* We set bit 1 if key has a reference on mm */ |
31 | |
32 | union futex_key { |
33 | struct { |
34 | u64 i_seq; |
35 | unsigned long pgoff; |
36 | unsigned int offset; |
37 | } shared; |
38 | struct { |
39 | union { |
40 | struct mm_struct *mm; |
41 | u64 __tmp; |
42 | }; |
43 | unsigned long address; |
44 | unsigned int offset; |
45 | } private; |
46 | struct { |
47 | u64 ptr; |
48 | unsigned long word; |
49 | unsigned int offset; |
50 | } both; |
51 | }; |
52 | |
53 | #define FUTEX_KEY_INIT (union futex_key) { .both = { .ptr = 0ULL } } |
54 | |
55 | #ifdef CONFIG_FUTEX |
56 | enum { |
57 | FUTEX_STATE_OK, |
58 | FUTEX_STATE_EXITING, |
59 | FUTEX_STATE_DEAD, |
60 | }; |
61 | |
62 | static inline void futex_init_task(struct task_struct *tsk) |
63 | { |
64 | tsk->robust_list = NULL; |
65 | #ifdef CONFIG_COMPAT |
66 | tsk->compat_robust_list = NULL; |
67 | #endif |
68 | INIT_LIST_HEAD(list: &tsk->pi_state_list); |
69 | tsk->pi_state_cache = NULL; |
70 | tsk->futex_state = FUTEX_STATE_OK; |
71 | mutex_init(&tsk->futex_exit_mutex); |
72 | } |
73 | |
74 | void futex_exit_recursive(struct task_struct *tsk); |
75 | void futex_exit_release(struct task_struct *tsk); |
76 | void futex_exec_release(struct task_struct *tsk); |
77 | |
78 | long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout, |
79 | u32 __user *uaddr2, u32 val2, u32 val3); |
80 | #else |
81 | static inline void futex_init_task(struct task_struct *tsk) { } |
82 | static inline void futex_exit_recursive(struct task_struct *tsk) { } |
83 | static inline void futex_exit_release(struct task_struct *tsk) { } |
84 | static inline void futex_exec_release(struct task_struct *tsk) { } |
85 | static inline long do_futex(u32 __user *uaddr, int op, u32 val, |
86 | ktime_t *timeout, u32 __user *uaddr2, |
87 | u32 val2, u32 val3) |
88 | { |
89 | return -EINVAL; |
90 | } |
91 | #endif |
92 | |
93 | #endif |
94 | |