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Thomas Gleixnerd2912cb2019-06-04 10:11:33 +02001/* SPDX-License-Identifier: GPL-2.0-only */
Vineet Gupta01b812b2013-01-18 15:12:22 +05302/*
3 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
4 *
Vineet Gupta01b812b2013-01-18 15:12:22 +05305 * 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
Vineet Gupta9138d412015-06-25 13:46:57 +053016#ifdef CONFIG_ARC_HAS_LLSC
17
Vineet Gupta01b812b2013-01-18 15:12:22 +053018#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg)\
19 \
Vineet Gupta31d30c82015-08-05 19:10:02 +053020 smp_mb(); \
Vineet Gupta01b812b2013-01-18 15:12:22 +053021 __asm__ __volatile__( \
Vineet Gupta9138d412015-06-25 13:46:57 +053022 "1: llock %1, [%2] \n" \
Vineet Gupta01b812b2013-01-18 15:12:22 +053023 insn "\n" \
Vineet Gupta9138d412015-06-25 13:46:57 +053024 "2: scond %0, [%2] \n" \
25 " bnz 1b \n" \
Vineet Gupta01b812b2013-01-18 15:12:22 +053026 " mov %0, 0 \n" \
27 "3: \n" \
28 " .section .fixup,\"ax\" \n" \
29 " .align 4 \n" \
30 "4: mov %0, %4 \n" \
Yuriy Kolerov6de60662015-08-12 17:23:32 +030031 " j 3b \n" \
Vineet Gupta01b812b2013-01-18 15:12:22 +053032 " .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) \
Vineet Gupta31d30c82015-08-05 19:10:02 +053041 : "cc", "memory"); \
42 smp_mb() \
Vineet Gupta01b812b2013-01-18 15:12:22 +053043
Vineet Gupta9138d412015-06-25 13:46:57 +053044#else /* !CONFIG_ARC_HAS_LLSC */
45
46#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg)\
47 \
Vineet Gupta31d30c82015-08-05 19:10:02 +053048 smp_mb(); \
Vineet Gupta9138d412015-06-25 13:46:57 +053049 __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" \
Yuriy Kolerov6de60662015-08-12 17:23:32 +030058 " j 3b \n" \
Vineet Gupta9138d412015-06-25 13:46:57 +053059 " .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) \
Vineet Gupta31d30c82015-08-05 19:10:02 +053068 : "cc", "memory"); \
69 smp_mb() \
Vineet Gupta9138d412015-06-25 13:46:57 +053070
71#endif
72
Jiri Slaby30d6e0a2017-08-24 09:31:05 +020073static inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval,
74 u32 __user *uaddr)
Vineet Gupta01b812b2013-01-18 15:12:22 +053075{
Vineet Gupta01b812b2013-01-18 15:12:22 +053076 int oldval = 0, ret;
77
Vineet Guptaeb2cd8b2015-08-06 19:11:06 +053078#ifndef CONFIG_ARC_HAS_LLSC
79 preempt_disable(); /* to guarantee atomic r-m-w of futex op */
80#endif
David Hildenbrand2f09b222015-05-11 17:52:17 +020081 pagefault_disable();
Vineet Gupta01b812b2013-01-18 15:12:22 +053082
83 switch (op) {
84 case FUTEX_OP_SET:
85 __futex_atomic_op("mov %0, %3", ret, oldval, uaddr, oparg);
86 break;
87 case FUTEX_OP_ADD:
Vineet Guptaed574e22015-08-05 19:23:34 +053088 /* oldval = *uaddr; *uaddr += oparg ; ret = *uaddr */
Vineet Gupta01b812b2013-01-18 15:12:22 +053089 __futex_atomic_op("add %0, %1, %3", ret, oldval, uaddr, oparg);
90 break;
91 case FUTEX_OP_OR:
92 __futex_atomic_op("or %0, %1, %3", ret, oldval, uaddr, oparg);
93 break;
94 case FUTEX_OP_ANDN:
95 __futex_atomic_op("bic %0, %1, %3", ret, oldval, uaddr, oparg);
96 break;
97 case FUTEX_OP_XOR:
98 __futex_atomic_op("xor %0, %1, %3", ret, oldval, uaddr, oparg);
99 break;
100 default:
101 ret = -ENOSYS;
102 }
103
David Hildenbrand2f09b222015-05-11 17:52:17 +0200104 pagefault_enable();
Vineet Guptaeb2cd8b2015-08-06 19:11:06 +0530105#ifndef CONFIG_ARC_HAS_LLSC
106 preempt_enable();
107#endif
Vineet Gupta01b812b2013-01-18 15:12:22 +0530108
Jiri Slaby30d6e0a2017-08-24 09:31:05 +0200109 if (!ret)
110 *oval = oldval;
111
Vineet Gupta01b812b2013-01-18 15:12:22 +0530112 return ret;
113}
114
Vineet Gupta31d30c82015-08-05 19:10:02 +0530115/*
116 * cmpxchg of futex (pagefaults disabled by caller)
Vineet Gupta882a95a2015-08-06 17:03:17 +0530117 * Return 0 for success, -EFAULT otherwise
Vineet Gupta01b812b2013-01-18 15:12:22 +0530118 */
119static inline int
Vineet Guptaed574e22015-08-05 19:23:34 +0530120futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, u32 expval,
121 u32 newval)
Vineet Gupta01b812b2013-01-18 15:12:22 +0530122{
Vineet Gupta882a95a2015-08-06 17:03:17 +0530123 int ret = 0;
Vineet Guptaed574e22015-08-05 19:23:34 +0530124 u32 existval;
Vineet Gupta01b812b2013-01-18 15:12:22 +0530125
Linus Torvalds96d4f262019-01-03 18:57:57 -0800126 if (!access_ok(uaddr, sizeof(u32)))
Vineet Gupta01b812b2013-01-18 15:12:22 +0530127 return -EFAULT;
128
Vineet Guptaeb2cd8b2015-08-06 19:11:06 +0530129#ifndef CONFIG_ARC_HAS_LLSC
130 preempt_disable(); /* to guarantee atomic r-m-w of futex op */
131#endif
Vineet Gupta31d30c82015-08-05 19:10:02 +0530132 smp_mb();
Vineet Gupta01b812b2013-01-18 15:12:22 +0530133
Vineet Gupta01b812b2013-01-18 15:12:22 +0530134 __asm__ __volatile__(
Vineet Gupta9138d412015-06-25 13:46:57 +0530135#ifdef CONFIG_ARC_HAS_LLSC
Vineet Gupta882a95a2015-08-06 17:03:17 +0530136 "1: llock %1, [%4] \n"
137 " brne %1, %2, 3f \n"
138 "2: scond %3, [%4] \n"
Vineet Gupta9138d412015-06-25 13:46:57 +0530139 " bnz 1b \n"
140#else
Vineet Gupta882a95a2015-08-06 17:03:17 +0530141 "1: ld %1, [%4] \n"
142 " brne %1, %2, 3f \n"
143 "2: st %3, [%4] \n"
Vineet Gupta9138d412015-06-25 13:46:57 +0530144#endif
Vineet Gupta01b812b2013-01-18 15:12:22 +0530145 "3: \n"
146 " .section .fixup,\"ax\" \n"
Vineet Gupta882a95a2015-08-06 17:03:17 +0530147 "4: mov %0, %5 \n"
Yuriy Kolerov6de60662015-08-12 17:23:32 +0300148 " j 3b \n"
Vineet Gupta01b812b2013-01-18 15:12:22 +0530149 " .previous \n"
150 " .section __ex_table,\"a\" \n"
151 " .align 4 \n"
152 " .word 1b, 4b \n"
153 " .word 2b, 4b \n"
154 " .previous\n"
Vineet Gupta882a95a2015-08-06 17:03:17 +0530155 : "+&r"(ret), "=&r"(existval)
Vineet Guptaed574e22015-08-05 19:23:34 +0530156 : "r"(expval), "r"(newval), "r"(uaddr), "ir"(-EFAULT)
Vineet Gupta01b812b2013-01-18 15:12:22 +0530157 : "cc", "memory");
158
Vineet Gupta31d30c82015-08-05 19:10:02 +0530159 smp_mb();
Vineet Gupta01b812b2013-01-18 15:12:22 +0530160
Vineet Guptaeb2cd8b2015-08-06 19:11:06 +0530161#ifndef CONFIG_ARC_HAS_LLSC
162 preempt_enable();
163#endif
Vineet Guptaed574e22015-08-05 19:23:34 +0530164 *uval = existval;
Vineet Gupta882a95a2015-08-06 17:03:17 +0530165 return ret;
Vineet Gupta01b812b2013-01-18 15:12:22 +0530166}
167
168#endif