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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. | |
f3dae07e | 11 | * It relies on preempt_disable() ensuring mutual exclusion. |
00f634bc LFT |
12 | * |
13 | */ | |
14 | ||
15 | /** | |
16 | * futex_atomic_op_inuser() - Atomic arithmetic operation with constant | |
17 | * argument and comparison of the previous | |
18 | * futex value with another constant. | |
19 | * | |
20 | * @encoded_op: encoded operation to execute | |
21 | * @uaddr: pointer to user space address | |
22 | * | |
23 | * Return: | |
24 | * 0 - On success | |
25 | * <0 - On error | |
26 | */ | |
27 | static inline int | |
28 | futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr) | |
29 | { | |
30 | int op = (encoded_op >> 28) & 7; | |
31 | int cmp = (encoded_op >> 24) & 15; | |
32 | int oparg = (encoded_op << 8) >> 20; | |
33 | int cmparg = (encoded_op << 20) >> 20; | |
34 | int oldval, ret; | |
35 | u32 tmp; | |
36 | ||
37 | if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28)) | |
38 | oparg = 1 << oparg; | |
39 | ||
f3dae07e | 40 | preempt_disable(); |
00f634bc LFT |
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(); | |
f3dae07e | 75 | preempt_enable(); |
00f634bc LFT |
76 | |
77 | if (ret == 0) { | |
78 | switch (cmp) { | |
79 | case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break; | |
80 | case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break; | |
81 | case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break; | |
82 | case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break; | |
83 | case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break; | |
84 | case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break; | |
85 | default: ret = -ENOSYS; | |
86 | } | |
87 | } | |
88 | return ret; | |
89 | } | |
90 | ||
91 | /** | |
92 | * futex_atomic_cmpxchg_inatomic() - Compare and exchange the content of the | |
93 | * uaddr with newval if the current value is | |
94 | * oldval. | |
95 | * @uval: pointer to store content of @uaddr | |
96 | * @uaddr: pointer to user space address | |
97 | * @oldval: old value | |
98 | * @newval: new value to store to @uaddr | |
99 | * | |
100 | * Return: | |
101 | * 0 - On success | |
102 | * <0 - On error | |
103 | */ | |
104 | static inline int | |
105 | futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, | |
106 | u32 oldval, u32 newval) | |
107 | { | |
108 | u32 val; | |
109 | ||
d9b9ff8c | 110 | preempt_disable(); |
00f634bc LFT |
111 | if (unlikely(get_user(val, uaddr) != 0)) |
112 | return -EFAULT; | |
113 | ||
114 | if (val == oldval && unlikely(put_user(newval, uaddr) != 0)) | |
115 | return -EFAULT; | |
116 | ||
117 | *uval = val; | |
d9b9ff8c | 118 | preempt_enable(); |
00f634bc LFT |
119 | |
120 | return 0; | |
121 | } | |
122 | ||
123 | #else | |
f8aaeace | 124 | static inline int |
8d7718aa | 125 | futex_atomic_op_inuser (int encoded_op, u32 __user *uaddr) |
f8aaeace JD |
126 | { |
127 | int op = (encoded_op >> 28) & 7; | |
128 | int cmp = (encoded_op >> 24) & 15; | |
129 | int oparg = (encoded_op << 8) >> 20; | |
130 | int cmparg = (encoded_op << 20) >> 20; | |
131 | int oldval = 0, ret; | |
132 | if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28)) | |
133 | oparg = 1 << oparg; | |
134 | ||
8d7718aa | 135 | if (! access_ok (VERIFY_WRITE, uaddr, sizeof(u32))) |
f8aaeace JD |
136 | return -EFAULT; |
137 | ||
a866374a | 138 | pagefault_disable(); |
f8aaeace JD |
139 | |
140 | switch (op) { | |
141 | case FUTEX_OP_SET: | |
142 | case FUTEX_OP_ADD: | |
143 | case FUTEX_OP_OR: | |
144 | case FUTEX_OP_ANDN: | |
145 | case FUTEX_OP_XOR: | |
146 | default: | |
147 | ret = -ENOSYS; | |
148 | } | |
149 | ||
a866374a | 150 | pagefault_enable(); |
f8aaeace JD |
151 | |
152 | if (!ret) { | |
153 | switch (cmp) { | |
154 | case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break; | |
155 | case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break; | |
156 | case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break; | |
157 | case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break; | |
158 | case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break; | |
159 | case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break; | |
160 | default: ret = -ENOSYS; | |
161 | } | |
162 | } | |
163 | return ret; | |
164 | } | |
165 | ||
e9056f13 | 166 | static inline int |
8d7718aa ML |
167 | futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, |
168 | u32 oldval, u32 newval) | |
e9056f13 IM |
169 | { |
170 | return -ENOSYS; | |
171 | } | |
172 | ||
00f634bc | 173 | #endif /* CONFIG_SMP */ |
f8aaeace | 174 | #endif |