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gerrit-public.fairphone.software / kernel / msm-4.19 / e589ed23dd27b890900eb7514f0a9e297d1e02b5 / . / arch / arm / include / asm / futex.h
blob: 9ee743b95de830e4db2d364e0209d0e282a97c9c [file] [log] [blame]
Mikael Petterssone589ed22008-08-20 09:36:07 +0100[diff] [blame^]1#ifndef _ASM_ARM_FUTEX_H
2#define _ASM_ARM_FUTEX_H
3
4#ifdef __KERNEL__
5
6#ifdef CONFIG_SMP
Jakub Jelinek4732efb2005-09-06 15:16:25 -0700[diff] [blame]7
Jeff Dikef8aaeace2006-01-08 01:01:32 -0800[diff] [blame]8#include <asm-generic/futex.h>
Jakub Jelinek4732efb2005-09-06 15:16:25 -0700[diff] [blame]9
Mikael Petterssone589ed22008-08-20 09:36:07 +0100[diff] [blame^]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
36static inline int
37futex_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
89static inline int
90futex_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"
102 "2: streqt %2, [%3]\n"
103 "3:\n"
104 " .section __ex_table,\"a\"\n"
105 " .align 3\n"
106 " .long 1b, 4f, 2b, 4f\n"
107 " .previous\n"
108 " .section .fixup,\"ax\"\n"
109 "4: mov %0, %4\n"
110 " b 3b\n"
111 " .previous"
112 : "=&r" (val)
113 : "r" (oldval), "r" (newval), "r" (uaddr), "Ir" (-EFAULT)
114 : "cc", "memory");
115
116 pagefault_enable(); /* subsumes preempt_enable() */
117
118 return val;
119}
120
121#endif /* !SMP */
122
123#endif /* __KERNEL__ */
124#endif /* _ASM_ARM_FUTEX_H */