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1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
4 *
5 * Vineetg: August 2010: From Android kernel work
6 */
7
8#ifndef _ASM_FUTEX_H
9#define _ASM_FUTEX_H
10
11#include <linux/futex.h>
12#include <linux/preempt.h>
13#include <linux/uaccess.h>
14#include <asm/errno.h>
15
16#ifdef CONFIG_ARC_HAS_LLSC
17
18#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg)\
19 \
20 smp_mb(); \
21 __asm__ __volatile__( \
22 "1: llock %1, [%2] \n" \
23 insn "\n" \
24 "2: scond %0, [%2] \n" \
25 " bnz 1b \n" \
26 " mov %0, 0 \n" \
27 "3: \n" \
28 " .section .fixup,\"ax\" \n" \
29 " .align 4 \n" \
30 "4: mov %0, %4 \n" \
31 " j 3b \n" \
32 " .previous \n" \
33 " .section __ex_table,\"a\" \n" \
34 " .align 4 \n" \
35 " .word 1b, 4b \n" \
36 " .word 2b, 4b \n" \
37 " .previous \n" \
38 \
39 : "=&r" (ret), "=&r" (oldval) \
40 : "r" (uaddr), "r" (oparg), "ir" (-EFAULT) \
41 : "cc", "memory"); \
42 smp_mb() \
43
44#else /* !CONFIG_ARC_HAS_LLSC */
45
46#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg)\
47 \
48 smp_mb(); \
49 __asm__ __volatile__( \
50 "1: ld %1, [%2] \n" \
51 insn "\n" \
52 "2: st %0, [%2] \n" \
53 " mov %0, 0 \n" \
54 "3: \n" \
55 " .section .fixup,\"ax\" \n" \
56 " .align 4 \n" \
57 "4: mov %0, %4 \n" \
58 " j 3b \n" \
59 " .previous \n" \
60 " .section __ex_table,\"a\" \n" \
61 " .align 4 \n" \
62 " .word 1b, 4b \n" \
63 " .word 2b, 4b \n" \
64 " .previous \n" \
65 \
66 : "=&r" (ret), "=&r" (oldval) \
67 : "r" (uaddr), "r" (oparg), "ir" (-EFAULT) \
68 : "cc", "memory"); \
69 smp_mb() \
70
71#endif
72
73static inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval,
74 u32 __user *uaddr)
75{
76 int oldval = 0, ret;
77
78 if (!access_ok(uaddr, sizeof(u32)))
79 return -EFAULT;
80
81#ifndef CONFIG_ARC_HAS_LLSC
82 preempt_disable(); /* to guarantee atomic r-m-w of futex op */
83#endif
84
85 switch (op) {
86 case FUTEX_OP_SET:
87 __futex_atomic_op("mov %0, %3", ret, oldval, uaddr, oparg);
88 break;
89 case FUTEX_OP_ADD:
90 /* oldval = *uaddr; *uaddr += oparg ; ret = *uaddr */
91 __futex_atomic_op("add %0, %1, %3", ret, oldval, uaddr, oparg);
92 break;
93 case FUTEX_OP_OR:
94 __futex_atomic_op("or %0, %1, %3", ret, oldval, uaddr, oparg);
95 break;
96 case FUTEX_OP_ANDN:
97 __futex_atomic_op("bic %0, %1, %3", ret, oldval, uaddr, oparg);
98 break;
99 case FUTEX_OP_XOR:
100 __futex_atomic_op("xor %0, %1, %3", ret, oldval, uaddr, oparg);
101 break;
102 default:
103 ret = -ENOSYS;
104 }
105
106#ifndef CONFIG_ARC_HAS_LLSC
107 preempt_enable();
108#endif
109
110 if (!ret)
111 *oval = oldval;
112
113 return ret;
114}
115
116/*
117 * cmpxchg of futex (pagefaults disabled by caller)
118 * Return 0 for success, -EFAULT otherwise
119 */
120static inline int
121futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, u32 expval,
122 u32 newval)
123{
124 int ret = 0;
125 u32 existval;
126
127 if (!access_ok(uaddr, sizeof(u32)))
128 return -EFAULT;
129
130#ifndef CONFIG_ARC_HAS_LLSC
131 preempt_disable(); /* to guarantee atomic r-m-w of futex op */
132#endif
133 smp_mb();
134
135 __asm__ __volatile__(
136#ifdef CONFIG_ARC_HAS_LLSC
137 "1: llock %1, [%4] \n"
138 " brne %1, %2, 3f \n"
139 "2: scond %3, [%4] \n"
140 " bnz 1b \n"
141#else
142 "1: ld %1, [%4] \n"
143 " brne %1, %2, 3f \n"
144 "2: st %3, [%4] \n"
145#endif
146 "3: \n"
147 " .section .fixup,\"ax\" \n"
148 "4: mov %0, %5 \n"
149 " j 3b \n"
150 " .previous \n"
151 " .section __ex_table,\"a\" \n"
152 " .align 4 \n"
153 " .word 1b, 4b \n"
154 " .word 2b, 4b \n"
155 " .previous\n"
156 : "+&r"(ret), "=&r"(existval)
157 : "r"(expval), "r"(newval), "r"(uaddr), "ir"(-EFAULT)
158 : "cc", "memory");
159
160 smp_mb();
161
162#ifndef CONFIG_ARC_HAS_LLSC
163 preempt_enable();
164#endif
165 *uval = existval;
166 return ret;
167}
168
169#endif
1/*
2 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
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 * Vineetg: August 2010: From Android kernel work
9 */
10
11#ifndef _ASM_FUTEX_H
12#define _ASM_FUTEX_H
13
14#include <linux/futex.h>
15#include <linux/preempt.h>
16#include <linux/uaccess.h>
17#include <asm/errno.h>
18
19#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg)\
20 \
21 __asm__ __volatile__( \
22 "1: ld %1, [%2] \n" \
23 insn "\n" \
24 "2: st %0, [%2] \n" \
25 " mov %0, 0 \n" \
26 "3: \n" \
27 " .section .fixup,\"ax\" \n" \
28 " .align 4 \n" \
29 "4: mov %0, %4 \n" \
30 " b 3b \n" \
31 " .previous \n" \
32 " .section __ex_table,\"a\" \n" \
33 " .align 4 \n" \
34 " .word 1b, 4b \n" \
35 " .word 2b, 4b \n" \
36 " .previous \n" \
37 \
38 : "=&r" (ret), "=&r" (oldval) \
39 : "r" (uaddr), "r" (oparg), "ir" (-EFAULT) \
40 : "cc", "memory")
41
42static inline int futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr)
43{
44 int op = (encoded_op >> 28) & 7;
45 int cmp = (encoded_op >> 24) & 15;
46 int oparg = (encoded_op << 8) >> 20;
47 int cmparg = (encoded_op << 20) >> 20;
48 int oldval = 0, ret;
49
50 if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
51 oparg = 1 << oparg;
52
53 if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
54 return -EFAULT;
55
56 pagefault_disable(); /* implies preempt_disable() */
57
58 switch (op) {
59 case FUTEX_OP_SET:
60 __futex_atomic_op("mov %0, %3", ret, oldval, uaddr, oparg);
61 break;
62 case FUTEX_OP_ADD:
63 __futex_atomic_op("add %0, %1, %3", ret, oldval, uaddr, oparg);
64 break;
65 case FUTEX_OP_OR:
66 __futex_atomic_op("or %0, %1, %3", ret, oldval, uaddr, oparg);
67 break;
68 case FUTEX_OP_ANDN:
69 __futex_atomic_op("bic %0, %1, %3", ret, oldval, uaddr, oparg);
70 break;
71 case FUTEX_OP_XOR:
72 __futex_atomic_op("xor %0, %1, %3", ret, oldval, uaddr, oparg);
73 break;
74 default:
75 ret = -ENOSYS;
76 }
77
78 pagefault_enable(); /* subsumes preempt_enable() */
79
80 if (!ret) {
81 switch (cmp) {
82 case FUTEX_OP_CMP_EQ:
83 ret = (oldval == cmparg);
84 break;
85 case FUTEX_OP_CMP_NE:
86 ret = (oldval != cmparg);
87 break;
88 case FUTEX_OP_CMP_LT:
89 ret = (oldval < cmparg);
90 break;
91 case FUTEX_OP_CMP_GE:
92 ret = (oldval >= cmparg);
93 break;
94 case FUTEX_OP_CMP_LE:
95 ret = (oldval <= cmparg);
96 break;
97 case FUTEX_OP_CMP_GT:
98 ret = (oldval > cmparg);
99 break;
100 default:
101 ret = -ENOSYS;
102 }
103 }
104 return ret;
105}
106
107/* Compare-xchg with preemption disabled.
108 * Notes:
109 * -Best-Effort: Exchg happens only if compare succeeds.
110 * If compare fails, returns; leaving retry/looping to upper layers
111 * -successful cmp-xchg: return orig value in @addr (same as cmp val)
112 * -Compare fails: return orig value in @addr
113 * -user access r/w fails: return -EFAULT
114 */
115static inline int
116futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, u32 oldval,
117 u32 newval)
118{
119 u32 val;
120
121 if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
122 return -EFAULT;
123
124 pagefault_disable(); /* implies preempt_disable() */
125
126 /* TBD : can use llock/scond */
127 __asm__ __volatile__(
128 "1: ld %0, [%3] \n"
129 " brne %0, %1, 3f \n"
130 "2: st %2, [%3] \n"
131 "3: \n"
132 " .section .fixup,\"ax\" \n"
133 "4: mov %0, %4 \n"
134 " b 3b \n"
135 " .previous \n"
136 " .section __ex_table,\"a\" \n"
137 " .align 4 \n"
138 " .word 1b, 4b \n"
139 " .word 2b, 4b \n"
140 " .previous\n"
141 : "=&r"(val)
142 : "r"(oldval), "r"(newval), "r"(uaddr), "ir"(-EFAULT)
143 : "cc", "memory");
144
145 pagefault_enable(); /* subsumes preempt_enable() */
146
147 *uval = val;
148 return val;
149}
150
151#endif