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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 | |
00f634bc LFT |
9 | #ifndef CONFIG_SMP |
10 | /* | |
11 | * The following implementation only for uniprocessor machines. | |
f3dae07e | 12 | * It relies on preempt_disable() ensuring mutual exclusion. |
00f634bc LFT |
13 | * |
14 | */ | |
15 | ||
16 | /** | |
30d6e0a4 | 17 | * arch_futex_atomic_op_inuser() - Atomic arithmetic operation with constant |
00f634bc LFT |
18 | * argument and comparison of the previous |
19 | * futex value with another constant. | |
20 | * | |
21 | * @encoded_op: encoded operation to execute | |
22 | * @uaddr: pointer to user space address | |
23 | * | |
24 | * Return: | |
25 | * 0 - On success | |
26 | * <0 - On error | |
27 | */ | |
28 | static inline int | |
30d6e0a4 | 29 | arch_futex_atomic_op_inuser(int op, u32 oparg, int *oval, u32 __user *uaddr) |
00f634bc | 30 | { |
00f634bc LFT |
31 | int oldval, ret; |
32 | u32 tmp; | |
33 | ||
f3dae07e | 34 | preempt_disable(); |
00f634bc LFT |
35 | pagefault_disable(); |
36 | ||
37 | ret = -EFAULT; | |
38 | if (unlikely(get_user(oldval, uaddr) != 0)) | |
39 | goto out_pagefault_enable; | |
40 | ||
41 | ret = 0; | |
42 | tmp = oldval; | |
43 | ||
44 | switch (op) { | |
45 | case FUTEX_OP_SET: | |
46 | tmp = oparg; | |
47 | break; | |
48 | case FUTEX_OP_ADD: | |
49 | tmp += oparg; | |
50 | break; | |
51 | case FUTEX_OP_OR: | |
52 | tmp |= oparg; | |
53 | break; | |
54 | case FUTEX_OP_ANDN: | |
55 | tmp &= ~oparg; | |
56 | break; | |
57 | case FUTEX_OP_XOR: | |
58 | tmp ^= oparg; | |
59 | break; | |
60 | default: | |
61 | ret = -ENOSYS; | |
62 | } | |
63 | ||
64 | if (ret == 0 && unlikely(put_user(tmp, uaddr) != 0)) | |
65 | ret = -EFAULT; | |
66 | ||
67 | out_pagefault_enable: | |
68 | pagefault_enable(); | |
f3dae07e | 69 | preempt_enable(); |
00f634bc | 70 | |
30d6e0a4 JS |
71 | if (ret == 0) |
72 | *oval = oldval; | |
73 | ||
00f634bc LFT |
74 | return ret; |
75 | } | |
76 | ||
77 | /** | |
78 | * futex_atomic_cmpxchg_inatomic() - Compare and exchange the content of the | |
79 | * uaddr with newval if the current value is | |
80 | * oldval. | |
81 | * @uval: pointer to store content of @uaddr | |
82 | * @uaddr: pointer to user space address | |
83 | * @oldval: old value | |
84 | * @newval: new value to store to @uaddr | |
85 | * | |
86 | * Return: | |
87 | * 0 - On success | |
88 | * <0 - On error | |
89 | */ | |
90 | static inline int | |
91 | futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, | |
92 | u32 oldval, u32 newval) | |
93 | { | |
94 | u32 val; | |
95 | ||
d9b9ff8c | 96 | preempt_disable(); |
fba7cd68 RP |
97 | if (unlikely(get_user(val, uaddr) != 0)) { |
98 | preempt_enable(); | |
00f634bc | 99 | return -EFAULT; |
fba7cd68 | 100 | } |
00f634bc | 101 | |
fba7cd68 RP |
102 | if (val == oldval && unlikely(put_user(newval, uaddr) != 0)) { |
103 | preempt_enable(); | |
00f634bc | 104 | return -EFAULT; |
fba7cd68 | 105 | } |
00f634bc LFT |
106 | |
107 | *uval = val; | |
d9b9ff8c | 108 | preempt_enable(); |
00f634bc LFT |
109 | |
110 | return 0; | |
111 | } | |
112 | ||
113 | #else | |
f8aaeace | 114 | static inline int |
30d6e0a4 | 115 | arch_futex_atomic_op_inuser(int op, u32 oparg, int *oval, u32 __user *uaddr) |
f8aaeace | 116 | { |
f8aaeace | 117 | int oldval = 0, ret; |
f8aaeace | 118 | |
a866374a | 119 | pagefault_disable(); |
f8aaeace JD |
120 | |
121 | switch (op) { | |
122 | case FUTEX_OP_SET: | |
123 | case FUTEX_OP_ADD: | |
124 | case FUTEX_OP_OR: | |
125 | case FUTEX_OP_ANDN: | |
126 | case FUTEX_OP_XOR: | |
127 | default: | |
128 | ret = -ENOSYS; | |
129 | } | |
130 | ||
a866374a | 131 | pagefault_enable(); |
f8aaeace | 132 | |
30d6e0a4 JS |
133 | if (!ret) |
134 | *oval = oldval; | |
135 | ||
f8aaeace JD |
136 | return ret; |
137 | } | |
138 | ||
e9056f13 | 139 | static inline int |
8d7718aa ML |
140 | futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, |
141 | u32 oldval, u32 newval) | |
e9056f13 IM |
142 | { |
143 | return -ENOSYS; | |
144 | } | |
145 | ||
00f634bc | 146 | #endif /* CONFIG_SMP */ |
f8aaeace | 147 | #endif |