1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
4 */
5#ifndef _ASM_FUTEX_H
6#define _ASM_FUTEX_H
7
8#include <linux/futex.h>
9#include <linux/uaccess.h>
10#include <asm/asm-extable.h>
11#include <asm/barrier.h>
12#include <asm/errno.h>
13
14#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg)		\
15{									\
16	__asm__ __volatile__(						\
17	"1:	ll.w	%1, %4 # __futex_atomic_op\n"		\
18	"	" insn	"				\n"	\
19	"2:	sc.w	$t0, %2				\n"	\
20	"	beqz	$t0, 1b				\n"	\
21	"3:						\n"	\
22	_ASM_EXTABLE_UACCESS_ERR(1b, 3b, %0)			\
23	_ASM_EXTABLE_UACCESS_ERR(2b, 3b, %0)			\
24	: "=r" (ret), "=&r" (oldval),				\
25	  "=ZC" (*uaddr)					\
26	: "0" (0), "ZC" (*uaddr), "Jr" (oparg)			\
27	: "memory", "t0");					\
28}
29
30static inline int
31arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *uaddr)
32{
33	int oldval = 0, ret = 0;
34
35	pagefault_disable();
36
37	switch (op) {
38	case FUTEX_OP_SET:
39		__futex_atomic_op("move $t0, %z5", ret, oldval, uaddr, oparg);
40		break;
41	case FUTEX_OP_ADD:
42		__futex_atomic_op("add.w $t0, %1, %z5", ret, oldval, uaddr, oparg);
43		break;
44	case FUTEX_OP_OR:
45		__futex_atomic_op("or	$t0, %1, %z5", ret, oldval, uaddr, oparg);
46		break;
47	case FUTEX_OP_ANDN:
48		__futex_atomic_op("and	$t0, %1, %z5", ret, oldval, uaddr, ~oparg);
49		break;
50	case FUTEX_OP_XOR:
51		__futex_atomic_op("xor	$t0, %1, %z5", ret, oldval, uaddr, oparg);
52		break;
53	default:
54		ret = -ENOSYS;
55	}
56
57	pagefault_enable();
58
59	if (!ret)
60		*oval = oldval;
61
62	return ret;
63}
64
65static inline int
66futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, u32 oldval, u32 newval)
67{
68	int ret = 0;
69	u32 val = 0;
70
71	if (!access_ok(uaddr, sizeof(u32)))
72		return -EFAULT;
73
74	__asm__ __volatile__(
75	"# futex_atomic_cmpxchg_inatomic			\n"
76	"1:	ll.w	%1, %3					\n"
77	"	bne	%1, %z4, 3f				\n"
78	"	move	$t0, %z5				\n"
79	"2:	sc.w	$t0, %2					\n"
80	"	beqz	$t0, 1b					\n"
81	"3:							\n"
82	__WEAK_LLSC_MB
83	_ASM_EXTABLE_UACCESS_ERR(1b, 3b, %0)
84	_ASM_EXTABLE_UACCESS_ERR(2b, 3b, %0)
85	: "+r" (ret), "=&r" (val), "=ZC" (*uaddr)
86	: "ZC" (*uaddr), "Jr" (oldval), "Jr" (newval)
87	: "memory", "t0");
88
89	*uval = val;
90
91	return ret;
92}
93
94#endif /* _ASM_FUTEX_H */
95