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f8aaeace JD |
1 | #ifndef _ASM_GENERIC_FUTEX_H |
2 | #define _ASM_GENERIC_FUTEX_H | |
3 | ||
f8aaeace | 4 | #include <linux/futex.h> |
730f412c | 5 | #include <linux/uaccess.h> |
f8aaeace | 6 | #include <asm/errno.h> |
f8aaeace | 7 | |
00f634bc LFT |
8 | #ifndef CONFIG_SMP |
9 | /* | |
10 | * The following implementation only for uniprocessor machines. | |
11 | * For UP, it's relies on the fact that pagefault_disable() also disables | |
12 | * preemption to ensure mutual exclusion. | |
13 | * | |
14 | */ | |
15 | ||
16 | /** | |
17 | * futex_atomic_op_inuser() - Atomic arithmetic operation with constant | |
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 | |
29 | futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr) | |
30 | { | |
31 | int op = (encoded_op >> 28) & 7; | |
32 | int cmp = (encoded_op >> 24) & 15; | |
33 | int oparg = (encoded_op << 8) >> 20; | |
34 | int cmparg = (encoded_op << 20) >> 20; | |
35 | int oldval, ret; | |
36 | u32 tmp; | |
37 | ||
38 | if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28)) | |
39 | oparg = 1 << oparg; | |
40 | ||
41 | pagefault_disable(); | |
42 | ||
43 | ret = -EFAULT; | |
44 | if (unlikely(get_user(oldval, uaddr) != 0)) | |
45 | goto out_pagefault_enable; | |
46 | ||
47 | ret = 0; | |
48 | tmp = oldval; | |
49 | ||
50 | switch (op) { | |
51 | case FUTEX_OP_SET: | |
52 | tmp = oparg; | |
53 | break; | |
54 | case FUTEX_OP_ADD: | |
55 | tmp += oparg; | |
56 | break; | |
57 | case FUTEX_OP_OR: | |
58 | tmp |= oparg; | |
59 | break; | |
60 | case FUTEX_OP_ANDN: | |
61 | tmp &= ~oparg; | |
62 | break; | |
63 | case FUTEX_OP_XOR: | |
64 | tmp ^= oparg; | |
65 | break; | |
66 | default: | |
67 | ret = -ENOSYS; | |
68 | } | |
69 | ||
70 | if (ret == 0 && unlikely(put_user(tmp, uaddr) != 0)) | |
71 | ret = -EFAULT; | |
72 | ||
73 | out_pagefault_enable: | |
74 | pagefault_enable(); | |
75 | ||
76 | if (ret == 0) { | |
77 | switch (cmp) { | |
78 | case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break; | |
79 | case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break; | |
80 | case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break; | |
81 | case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break; | |
82 | case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break; | |
83 | case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break; | |
84 | default: ret = -ENOSYS; | |
85 | } | |
86 | } | |
87 | return ret; | |
88 | } | |
89 | ||
90 | /** | |
91 | * futex_atomic_cmpxchg_inatomic() - Compare and exchange the content of the | |
92 | * uaddr with newval if the current value is | |
93 | * oldval. | |
94 | * @uval: pointer to store content of @uaddr | |
95 | * @uaddr: pointer to user space address | |
96 | * @oldval: old value | |
97 | * @newval: new value to store to @uaddr | |
98 | * | |
99 | * Return: | |
100 | * 0 - On success | |
101 | * <0 - On error | |
102 | */ | |
103 | static inline int | |
104 | futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, | |
105 | u32 oldval, u32 newval) | |
106 | { | |
107 | u32 val; | |
108 | ||
109 | if (unlikely(get_user(val, uaddr) != 0)) | |
110 | return -EFAULT; | |
111 | ||
112 | if (val == oldval && unlikely(put_user(newval, uaddr) != 0)) | |
113 | return -EFAULT; | |
114 | ||
115 | *uval = val; | |
116 | ||
117 | return 0; | |
118 | } | |
119 | ||
120 | #else | |
f8aaeace | 121 | static inline int |
8d7718aa | 122 | futex_atomic_op_inuser (int encoded_op, u32 __user *uaddr) |
f8aaeace JD |
123 | { |
124 | int op = (encoded_op >> 28) & 7; | |
125 | int cmp = (encoded_op >> 24) & 15; | |
126 | int oparg = (encoded_op << 8) >> 20; | |
127 | int cmparg = (encoded_op << 20) >> 20; | |
128 | int oldval = 0, ret; | |
129 | if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28)) | |
130 | oparg = 1 << oparg; | |
131 | ||
8d7718aa | 132 | if (! access_ok (VERIFY_WRITE, uaddr, sizeof(u32))) |
f8aaeace JD |
133 | return -EFAULT; |
134 | ||
a866374a | 135 | pagefault_disable(); |
f8aaeace JD |
136 | |
137 | switch (op) { | |
138 | case FUTEX_OP_SET: | |
139 | case FUTEX_OP_ADD: | |
140 | case FUTEX_OP_OR: | |
141 | case FUTEX_OP_ANDN: | |
142 | case FUTEX_OP_XOR: | |
143 | default: | |
144 | ret = -ENOSYS; | |
145 | } | |
146 | ||
a866374a | 147 | pagefault_enable(); |
f8aaeace JD |
148 | |
149 | if (!ret) { | |
150 | switch (cmp) { | |
151 | case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break; | |
152 | case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break; | |
153 | case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break; | |
154 | case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break; | |
155 | case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break; | |
156 | case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break; | |
157 | default: ret = -ENOSYS; | |
158 | } | |
159 | } | |
160 | return ret; | |
161 | } | |
162 | ||
e9056f13 | 163 | static inline int |
8d7718aa ML |
164 | futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, |
165 | u32 oldval, u32 newval) | |
e9056f13 IM |
166 | { |
167 | return -ENOSYS; | |
168 | } | |
169 | ||
00f634bc | 170 | #endif /* CONFIG_SMP */ |
f8aaeace | 171 | #endif |