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6170a974 CM |
1 | /* |
2 | * Copyright (C) 2012 ARM Ltd. | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License version 2 as | |
6 | * published by the Free Software Foundation. | |
7 | * | |
8 | * This program is distributed in the hope that it will be useful, | |
9 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
11 | * GNU General Public License for more details. | |
12 | * | |
13 | * You should have received a copy of the GNU General Public License | |
14 | * along with this program. If not, see <http://www.gnu.org/licenses/>. | |
15 | */ | |
16 | #ifndef __ASM_FUTEX_H | |
17 | #define __ASM_FUTEX_H | |
18 | ||
19 | #ifdef __KERNEL__ | |
20 | ||
21 | #include <linux/futex.h> | |
22 | #include <linux/uaccess.h> | |
338d4f49 | 23 | |
6170a974 CM |
24 | #include <asm/errno.h> |
25 | ||
03110a5c WD |
26 | #define FUTEX_MAX_LOOPS 128 /* What's the largest number you can think of? */ |
27 | ||
6170a974 | 28 | #define __futex_atomic_op(insn, ret, oldval, uaddr, tmp, oparg) \ |
bd38967d | 29 | do { \ |
03110a5c WD |
30 | unsigned int loops = FUTEX_MAX_LOOPS; \ |
31 | \ | |
bd38967d | 32 | uaccess_enable(); \ |
6170a974 | 33 | asm volatile( \ |
0ea366f5 | 34 | " prfm pstl1strm, %2\n" \ |
8e86f0b4 | 35 | "1: ldxr %w1, %2\n" \ |
6170a974 | 36 | insn "\n" \ |
045afc24 | 37 | "2: stlxr %w0, %w3, %2\n" \ |
03110a5c WD |
38 | " cbz %w0, 3f\n" \ |
39 | " sub %w4, %w4, %w0\n" \ | |
40 | " cbnz %w4, 1b\n" \ | |
41 | " mov %w0, %w7\n" \ | |
6170a974 | 42 | "3:\n" \ |
03110a5c | 43 | " dmb ish\n" \ |
6170a974 | 44 | " .pushsection .fixup,\"ax\"\n" \ |
4da7a56c | 45 | " .align 2\n" \ |
03110a5c | 46 | "4: mov %w0, %w6\n" \ |
6170a974 CM |
47 | " b 3b\n" \ |
48 | " .popsection\n" \ | |
6c94f27a AB |
49 | _ASM_EXTABLE(1b, 4b) \ |
50 | _ASM_EXTABLE(2b, 4b) \ | |
03110a5c WD |
51 | : "=&r" (ret), "=&r" (oldval), "+Q" (*uaddr), "=&r" (tmp), \ |
52 | "+r" (loops) \ | |
53 | : "r" (oparg), "Ir" (-EFAULT), "Ir" (-EAGAIN) \ | |
bd38967d CM |
54 | : "memory"); \ |
55 | uaccess_disable(); \ | |
56 | } while (0) | |
6170a974 CM |
57 | |
58 | static inline int | |
91b2d344 | 59 | arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *_uaddr) |
6170a974 | 60 | { |
ff8acf92 | 61 | int oldval = 0, ret, tmp; |
91b2d344 | 62 | u32 __user *uaddr = __uaccess_mask_ptr(_uaddr); |
6170a974 | 63 | |
2f09b227 | 64 | pagefault_disable(); |
6170a974 CM |
65 | |
66 | switch (op) { | |
67 | case FUTEX_OP_SET: | |
03110a5c | 68 | __futex_atomic_op("mov %w3, %w5", |
6170a974 CM |
69 | ret, oldval, uaddr, tmp, oparg); |
70 | break; | |
71 | case FUTEX_OP_ADD: | |
03110a5c | 72 | __futex_atomic_op("add %w3, %w1, %w5", |
6170a974 CM |
73 | ret, oldval, uaddr, tmp, oparg); |
74 | break; | |
75 | case FUTEX_OP_OR: | |
03110a5c | 76 | __futex_atomic_op("orr %w3, %w1, %w5", |
6170a974 CM |
77 | ret, oldval, uaddr, tmp, oparg); |
78 | break; | |
79 | case FUTEX_OP_ANDN: | |
03110a5c | 80 | __futex_atomic_op("and %w3, %w1, %w5", |
6170a974 CM |
81 | ret, oldval, uaddr, tmp, ~oparg); |
82 | break; | |
83 | case FUTEX_OP_XOR: | |
03110a5c | 84 | __futex_atomic_op("eor %w3, %w1, %w5", |
6170a974 CM |
85 | ret, oldval, uaddr, tmp, oparg); |
86 | break; | |
87 | default: | |
88 | ret = -ENOSYS; | |
89 | } | |
90 | ||
2f09b227 | 91 | pagefault_enable(); |
6170a974 | 92 | |
30d6e0a4 JS |
93 | if (!ret) |
94 | *oval = oldval; | |
95 | ||
6170a974 CM |
96 | return ret; |
97 | } | |
98 | ||
99 | static inline int | |
91b2d344 | 100 | futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *_uaddr, |
6170a974 CM |
101 | u32 oldval, u32 newval) |
102 | { | |
103 | int ret = 0; | |
03110a5c | 104 | unsigned int loops = FUTEX_MAX_LOOPS; |
6170a974 | 105 | u32 val, tmp; |
91b2d344 | 106 | u32 __user *uaddr; |
6170a974 | 107 | |
96d4f267 | 108 | if (!access_ok(_uaddr, sizeof(u32))) |
6170a974 CM |
109 | return -EFAULT; |
110 | ||
91b2d344 | 111 | uaddr = __uaccess_mask_ptr(_uaddr); |
bd38967d | 112 | uaccess_enable(); |
6170a974 | 113 | asm volatile("// futex_atomic_cmpxchg_inatomic\n" |
0ea366f5 | 114 | " prfm pstl1strm, %2\n" |
8e86f0b4 | 115 | "1: ldxr %w1, %2\n" |
03110a5c WD |
116 | " sub %w3, %w1, %w5\n" |
117 | " cbnz %w3, 4f\n" | |
118 | "2: stlxr %w3, %w6, %2\n" | |
119 | " cbz %w3, 3f\n" | |
120 | " sub %w4, %w4, %w3\n" | |
121 | " cbnz %w4, 1b\n" | |
122 | " mov %w0, %w8\n" | |
6170a974 | 123 | "3:\n" |
03110a5c WD |
124 | " dmb ish\n" |
125 | "4:\n" | |
6170a974 | 126 | " .pushsection .fixup,\"ax\"\n" |
03110a5c WD |
127 | "5: mov %w0, %w7\n" |
128 | " b 4b\n" | |
6170a974 | 129 | " .popsection\n" |
03110a5c WD |
130 | _ASM_EXTABLE(1b, 5b) |
131 | _ASM_EXTABLE(2b, 5b) | |
132 | : "+r" (ret), "=&r" (val), "+Q" (*uaddr), "=&r" (tmp), "+r" (loops) | |
133 | : "r" (oldval), "r" (newval), "Ir" (-EFAULT), "Ir" (-EAGAIN) | |
95c41896 | 134 | : "memory"); |
bd38967d | 135 | uaccess_disable(); |
6170a974 | 136 | |
8e4e0ac0 WD |
137 | if (!ret) |
138 | *uval = val; | |
139 | ||
6170a974 CM |
140 | return ret; |
141 | } | |
142 | ||
143 | #endif /* __KERNEL__ */ | |
144 | #endif /* __ASM_FUTEX_H */ |