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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
f8aaeace JD |
2 | #ifndef _ASM_GENERIC_FUTEX_H |
3 | #define _ASM_GENERIC_FUTEX_H | |
4 | ||
f8aaeace | 5 | #include <linux/futex.h> |
730f412c | 6 | #include <linux/uaccess.h> |
f8aaeace | 7 | #include <asm/errno.h> |
f8aaeace | 8 | |
3f2bedab | 9 | #ifndef futex_atomic_cmpxchg_inatomic |
00f634bc LFT |
10 | #ifndef CONFIG_SMP |
11 | /* | |
12 | * The following implementation only for uniprocessor machines. | |
f3dae07e | 13 | * It relies on preempt_disable() ensuring mutual exclusion. |
00f634bc LFT |
14 | * |
15 | */ | |
3f2bedab | 16 | #define futex_atomic_cmpxchg_inatomic(uval, uaddr, oldval, newval) \ |
4e0d8463 | 17 | futex_atomic_cmpxchg_inatomic_local(uval, uaddr, oldval, newval) |
3f2bedab | 18 | #define arch_futex_atomic_op_inuser(op, oparg, oval, uaddr) \ |
4e0d8463 | 19 | futex_atomic_op_inuser_local(op, oparg, oval, uaddr) |
3f2bedab AB |
20 | #endif /* CONFIG_SMP */ |
21 | #endif | |
00f634bc LFT |
22 | |
23 | /** | |
0f09c274 | 24 | * futex_atomic_op_inuser_local() - Atomic arithmetic operation with constant |
00f634bc LFT |
25 | * argument and comparison of the previous |
26 | * futex value with another constant. | |
27 | * | |
28 | * @encoded_op: encoded operation to execute | |
29 | * @uaddr: pointer to user space address | |
30 | * | |
31 | * Return: | |
32 | * 0 - On success | |
42750351 WD |
33 | * -EFAULT - User access resulted in a page fault |
34 | * -EAGAIN - Atomic operation was unable to complete due to contention | |
35 | * -ENOSYS - Operation not supported | |
00f634bc LFT |
36 | */ |
37 | static inline int | |
3f2bedab | 38 | futex_atomic_op_inuser_local(int op, u32 oparg, int *oval, u32 __user *uaddr) |
00f634bc | 39 | { |
00f634bc LFT |
40 | int oldval, ret; |
41 | u32 tmp; | |
42 | ||
f3dae07e | 43 | preempt_disable(); |
00f634bc LFT |
44 | |
45 | ret = -EFAULT; | |
46 | if (unlikely(get_user(oldval, uaddr) != 0)) | |
47 | goto out_pagefault_enable; | |
48 | ||
49 | ret = 0; | |
50 | tmp = oldval; | |
51 | ||
52 | switch (op) { | |
53 | case FUTEX_OP_SET: | |
54 | tmp = oparg; | |
55 | break; | |
56 | case FUTEX_OP_ADD: | |
57 | tmp += oparg; | |
58 | break; | |
59 | case FUTEX_OP_OR: | |
60 | tmp |= oparg; | |
61 | break; | |
62 | case FUTEX_OP_ANDN: | |
63 | tmp &= ~oparg; | |
64 | break; | |
65 | case FUTEX_OP_XOR: | |
66 | tmp ^= oparg; | |
67 | break; | |
68 | default: | |
69 | ret = -ENOSYS; | |
70 | } | |
71 | ||
72 | if (ret == 0 && unlikely(put_user(tmp, uaddr) != 0)) | |
73 | ret = -EFAULT; | |
74 | ||
75 | out_pagefault_enable: | |
f3dae07e | 76 | preempt_enable(); |
00f634bc | 77 | |
30d6e0a4 JS |
78 | if (ret == 0) |
79 | *oval = oldval; | |
80 | ||
00f634bc LFT |
81 | return ret; |
82 | } | |
83 | ||
84 | /** | |
3f2bedab | 85 | * futex_atomic_cmpxchg_inatomic_local() - Compare and exchange the content of the |
00f634bc LFT |
86 | * uaddr with newval if the current value is |
87 | * oldval. | |
88 | * @uval: pointer to store content of @uaddr | |
89 | * @uaddr: pointer to user space address | |
90 | * @oldval: old value | |
91 | * @newval: new value to store to @uaddr | |
92 | * | |
93 | * Return: | |
94 | * 0 - On success | |
42750351 WD |
95 | * -EFAULT - User access resulted in a page fault |
96 | * -EAGAIN - Atomic operation was unable to complete due to contention | |
00f634bc LFT |
97 | */ |
98 | static inline int | |
3f2bedab | 99 | futex_atomic_cmpxchg_inatomic_local(u32 *uval, u32 __user *uaddr, |
00f634bc LFT |
100 | u32 oldval, u32 newval) |
101 | { | |
102 | u32 val; | |
103 | ||
d9b9ff8c | 104 | preempt_disable(); |
fba7cd68 RP |
105 | if (unlikely(get_user(val, uaddr) != 0)) { |
106 | preempt_enable(); | |
00f634bc | 107 | return -EFAULT; |
fba7cd68 | 108 | } |
00f634bc | 109 | |
fba7cd68 RP |
110 | if (val == oldval && unlikely(put_user(newval, uaddr) != 0)) { |
111 | preempt_enable(); | |
00f634bc | 112 | return -EFAULT; |
fba7cd68 | 113 | } |
00f634bc LFT |
114 | |
115 | *uval = val; | |
d9b9ff8c | 116 | preempt_enable(); |
00f634bc LFT |
117 | |
118 | return 0; | |
119 | } | |
120 | ||
f8aaeace | 121 | #endif |