1#ifndef _ASM_GENERIC_FUTEX_H
 2#define _ASM_GENERIC_FUTEX_H
 3
 4#include <linux/futex.h>
 5#include <linux/uaccess.h>
 6#include <asm/errno.h>
 7
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 8static inline int
 9futex_atomic_op_inuser (int encoded_op, u32 __user *uaddr)
10{
11	int op = (encoded_op >> 28) & 7;
12	int cmp = (encoded_op >> 24) & 15;
13	int oparg = (encoded_op << 8) >> 20;
14	int cmparg = (encoded_op << 20) >> 20;
15	int oldval = 0, ret;
16	if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
17		oparg = 1 << oparg;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
18
19	if (! access_ok (VERIFY_WRITE, uaddr, sizeof(u32)))
 
20		return -EFAULT;
 
 
 
 
 
 
 
 
 
 
 
 
 
21
22	pagefault_disable();
23
24	switch (op) {
25	case FUTEX_OP_SET:
26	case FUTEX_OP_ADD:
27	case FUTEX_OP_OR:
28	case FUTEX_OP_ANDN:
29	case FUTEX_OP_XOR:
30	default:
31		ret = -ENOSYS;
32	}
33
34	pagefault_enable();
35
36	if (!ret) {
37		switch (cmp) {
38		case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break;
39		case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break;
40		case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break;
41		case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break;
42		case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break;
43		case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break;
44		default: ret = -ENOSYS;
45		}
46	}
47	return ret;
48}
49
50static inline int
51futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
52			      u32 oldval, u32 newval)
53{
54	return -ENOSYS;
55}
56
 
57#endif

  1/* SPDX-License-Identifier: GPL-2.0 */
  2#ifndef _ASM_GENERIC_FUTEX_H
  3#define _ASM_GENERIC_FUTEX_H
  4
  5#include <linux/futex.h>
  6#include <linux/uaccess.h>
  7#include <asm/errno.h>
  8
  9#ifndef CONFIG_SMP
 10/*
 11 * The following implementation only for uniprocessor machines.
 12 * It relies on preempt_disable() ensuring mutual exclusion.
 13 *
 14 */
 15
 16/**
 17 * arch_futex_atomic_op_inuser() - Atomic arithmetic operation with constant
 18 *			  argument and comparison of the previous
 19 *			  futex value with another constant.
 20 *
 21 * @encoded_op:	encoded operation to execute
 22 * @uaddr:	pointer to user space address
 23 *
 24 * Return:
 25 * 0 - On success
 26 * <0 - On error
 27 */
 28static inline int
 29arch_futex_atomic_op_inuser(int op, u32 oparg, int *oval, u32 __user *uaddr)
 30{
 31	int oldval, ret;
 32	u32 tmp;
 33
 34	preempt_disable();
 35	pagefault_disable();
 36
 37	ret = -EFAULT;
 38	if (unlikely(get_user(oldval, uaddr) != 0))
 39		goto out_pagefault_enable;
 40
 41	ret = 0;
 42	tmp = oldval;
 43
 44	switch (op) {
 45	case FUTEX_OP_SET:
 46		tmp = oparg;
 47		break;
 48	case FUTEX_OP_ADD:
 49		tmp += oparg;
 50		break;
 51	case FUTEX_OP_OR:
 52		tmp |= oparg;
 53		break;
 54	case FUTEX_OP_ANDN:
 55		tmp &= ~oparg;
 56		break;
 57	case FUTEX_OP_XOR:
 58		tmp ^= oparg;
 59		break;
 60	default:
 61		ret = -ENOSYS;
 62	}
 63
 64	if (ret == 0 && unlikely(put_user(tmp, uaddr) != 0))
 65		ret = -EFAULT;
 66
 67out_pagefault_enable:
 68	pagefault_enable();
 69	preempt_enable();
 70
 71	if (ret == 0)
 72		*oval = oldval;
 73
 74	return ret;
 75}
 76
 77/**
 78 * futex_atomic_cmpxchg_inatomic() - Compare and exchange the content of the
 79 *				uaddr with newval if the current value is
 80 *				oldval.
 81 * @uval:	pointer to store content of @uaddr
 82 * @uaddr:	pointer to user space address
 83 * @oldval:	old value
 84 * @newval:	new value to store to @uaddr
 85 *
 86 * Return:
 87 * 0 - On success
 88 * <0 - On error
 89 */
 90static inline int
 91futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
 92			      u32 oldval, u32 newval)
 93{
 94	u32 val;
 95
 96	preempt_disable();
 97	if (unlikely(get_user(val, uaddr) != 0)) {
 98		preempt_enable();
 99		return -EFAULT;
100	}
101
102	if (val == oldval && unlikely(put_user(newval, uaddr) != 0)) {
103		preempt_enable();
104		return -EFAULT;
105	}
106
107	*uval = val;
108	preempt_enable();
109
110	return 0;
111}
112
113#else
114static inline int
115arch_futex_atomic_op_inuser(int op, u32 oparg, int *oval, u32 __user *uaddr)
116{
117	int oldval = 0, ret;
118
119	pagefault_disable();
120
121	switch (op) {
122	case FUTEX_OP_SET:
123	case FUTEX_OP_ADD:
124	case FUTEX_OP_OR:
125	case FUTEX_OP_ANDN:
126	case FUTEX_OP_XOR:
127	default:
128		ret = -ENOSYS;
129	}
130
131	pagefault_enable();
132
133	if (!ret)
134		*oval = oldval;
135
 
 
 
 
 
 
 
 
136	return ret;
137}
138
139static inline int
140futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
141			      u32 oldval, u32 newval)
142{
143	return -ENOSYS;
144}
145
146#endif /* CONFIG_SMP */
147#endif