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e589ed23 MP |
1 | #ifndef _ASM_ARM_FUTEX_H |
2 | #define _ASM_ARM_FUTEX_H | |
3 | ||
4 | #ifdef __KERNEL__ | |
5 | ||
6 | #ifdef CONFIG_SMP | |
4732efbe | 7 | |
f8aaeace | 8 | #include <asm-generic/futex.h> |
4732efbe | 9 | |
e589ed23 MP |
10 | #else /* !SMP, we can work around lack of atomic ops by disabling preemption */ |
11 | ||
12 | #include <linux/futex.h> | |
13 | #include <linux/preempt.h> | |
14 | #include <linux/uaccess.h> | |
15 | #include <asm/errno.h> | |
16 | ||
17 | #define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \ | |
18 | __asm__ __volatile__( \ | |
19 | "1: ldrt %1, [%2]\n" \ | |
20 | " " insn "\n" \ | |
21 | "2: strt %0, [%2]\n" \ | |
22 | " mov %0, #0\n" \ | |
23 | "3:\n" \ | |
24 | " .section __ex_table,\"a\"\n" \ | |
25 | " .align 3\n" \ | |
26 | " .long 1b, 4f, 2b, 4f\n" \ | |
27 | " .previous\n" \ | |
28 | " .section .fixup,\"ax\"\n" \ | |
29 | "4: mov %0, %4\n" \ | |
30 | " b 3b\n" \ | |
31 | " .previous" \ | |
32 | : "=&r" (ret), "=&r" (oldval) \ | |
33 | : "r" (uaddr), "r" (oparg), "Ir" (-EFAULT) \ | |
34 | : "cc", "memory") | |
35 | ||
36 | static inline int | |
37 | futex_atomic_op_inuser (int encoded_op, int __user *uaddr) | |
38 | { | |
39 | int op = (encoded_op >> 28) & 7; | |
40 | int cmp = (encoded_op >> 24) & 15; | |
41 | int oparg = (encoded_op << 8) >> 20; | |
42 | int cmparg = (encoded_op << 20) >> 20; | |
43 | int oldval = 0, ret; | |
44 | ||
45 | if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28)) | |
46 | oparg = 1 << oparg; | |
47 | ||
48 | if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int))) | |
49 | return -EFAULT; | |
50 | ||
51 | pagefault_disable(); /* implies preempt_disable() */ | |
52 | ||
53 | switch (op) { | |
54 | case FUTEX_OP_SET: | |
55 | __futex_atomic_op("mov %0, %3", ret, oldval, uaddr, oparg); | |
56 | break; | |
57 | case FUTEX_OP_ADD: | |
58 | __futex_atomic_op("add %0, %1, %3", ret, oldval, uaddr, oparg); | |
59 | break; | |
60 | case FUTEX_OP_OR: | |
61 | __futex_atomic_op("orr %0, %1, %3", ret, oldval, uaddr, oparg); | |
62 | break; | |
63 | case FUTEX_OP_ANDN: | |
64 | __futex_atomic_op("and %0, %1, %3", ret, oldval, uaddr, ~oparg); | |
65 | break; | |
66 | case FUTEX_OP_XOR: | |
67 | __futex_atomic_op("eor %0, %1, %3", ret, oldval, uaddr, oparg); | |
68 | break; | |
69 | default: | |
70 | ret = -ENOSYS; | |
71 | } | |
72 | ||
73 | pagefault_enable(); /* subsumes preempt_enable() */ | |
74 | ||
75 | if (!ret) { | |
76 | switch (cmp) { | |
77 | case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break; | |
78 | case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break; | |
79 | case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break; | |
80 | case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break; | |
81 | case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break; | |
82 | case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break; | |
83 | default: ret = -ENOSYS; | |
84 | } | |
85 | } | |
86 | return ret; | |
87 | } | |
88 | ||
89 | static inline int | |
90 | futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval) | |
91 | { | |
92 | int val; | |
93 | ||
94 | if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int))) | |
95 | return -EFAULT; | |
96 | ||
97 | pagefault_disable(); /* implies preempt_disable() */ | |
98 | ||
99 | __asm__ __volatile__("@futex_atomic_cmpxchg_inatomic\n" | |
100 | "1: ldrt %0, [%3]\n" | |
101 | " teq %0, %1\n" | |
b86040a5 | 102 | " it eq @ explicit IT needed for the 2b label\n" |
e589ed23 MP |
103 | "2: streqt %2, [%3]\n" |
104 | "3:\n" | |
105 | " .section __ex_table,\"a\"\n" | |
106 | " .align 3\n" | |
107 | " .long 1b, 4f, 2b, 4f\n" | |
108 | " .previous\n" | |
109 | " .section .fixup,\"ax\"\n" | |
110 | "4: mov %0, %4\n" | |
111 | " b 3b\n" | |
112 | " .previous" | |
113 | : "=&r" (val) | |
114 | : "r" (oldval), "r" (newval), "r" (uaddr), "Ir" (-EFAULT) | |
115 | : "cc", "memory"); | |
116 | ||
117 | pagefault_enable(); /* subsumes preempt_enable() */ | |
118 | ||
119 | return val; | |
120 | } | |
121 | ||
122 | #endif /* !SMP */ | |
123 | ||
124 | #endif /* __KERNEL__ */ | |
125 | #endif /* _ASM_ARM_FUTEX_H */ |