summaryrefslogtreecommitdiff
path: root/arch/xtensa/include/asm/futex.h
blob: 9538b0f7953c3d4faf8bc3189392b309ca7253fb (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
/*
 * Atomic futex routines
 *
 * Based on the PowerPC implementataion
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Copyright (C) 2013 TangoTec Ltd.
 *
 * Baruch Siach <baruch@tkos.co.il>
 */

#ifndef _ASM_XTENSA_FUTEX_H
#define _ASM_XTENSA_FUTEX_H

#include <linux/futex.h>
#include <linux/uaccess.h>
#include <linux/errno.h>

#if XCHAL_HAVE_EXCLUSIVE
#define __futex_atomic_op(insn, ret, old, uaddr, arg)	\
	__asm__ __volatile(				\
	"1:	l32ex	%[oldval], %[addr]\n"		\
		insn "\n"				\
	"2:	s32ex	%[newval], %[addr]\n"		\
	"	getex	%[newval]\n"			\
	"	beqz	%[newval], 1b\n"		\
	"	movi	%[newval], 0\n"			\
	"3:\n"						\
	"	.section .fixup,\"ax\"\n"		\
	"	.align 4\n"				\
	"	.literal_position\n"			\
	"5:	movi	%[oldval], 3b\n"		\
	"	movi	%[newval], %[fault]\n"		\
	"	jx	%[oldval]\n"			\
	"	.previous\n"				\
	"	.section __ex_table,\"a\"\n"		\
	"	.long 1b, 5b, 2b, 5b\n"			\
	"	.previous\n"				\
	: [oldval] "=&r" (old), [newval] "=&r" (ret)	\
	: [addr] "r" (uaddr), [oparg] "r" (arg),	\
	  [fault] "I" (-EFAULT)				\
	: "memory")
#elif XCHAL_HAVE_S32C1I
#define __futex_atomic_op(insn, ret, old, uaddr, arg)	\
	__asm__ __volatile(				\
	"1:	l32i	%[oldval], %[addr], 0\n"	\
		insn "\n"				\
	"	wsr	%[oldval], scompare1\n"		\
	"2:	s32c1i	%[newval], %[addr], 0\n"	\
	"	bne	%[newval], %[oldval], 1b\n"	\
	"	movi	%[newval], 0\n"			\
	"3:\n"						\
	"	.section .fixup,\"ax\"\n"		\
	"	.align 4\n"				\
	"	.literal_position\n"			\
	"5:	movi	%[oldval], 3b\n"		\
	"	movi	%[newval], %[fault]\n"		\
	"	jx	%[oldval]\n"			\
	"	.previous\n"				\
	"	.section __ex_table,\"a\"\n"		\
	"	.long 1b, 5b, 2b, 5b\n"			\
	"	.previous\n"				\
	: [oldval] "=&r" (old), [newval] "=&r" (ret)	\
	: [addr] "r" (uaddr), [oparg] "r" (arg),	\
	  [fault] "I" (-EFAULT)				\
	: "memory")
#endif

static inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval,
		u32 __user *uaddr)
{
#if XCHAL_HAVE_S32C1I || XCHAL_HAVE_EXCLUSIVE
	int oldval = 0, ret;

	pagefault_disable();

	switch (op) {
	case FUTEX_OP_SET:
		__futex_atomic_op("mov %[newval], %[oparg]",
				  ret, oldval, uaddr, oparg);
		break;
	case FUTEX_OP_ADD:
		__futex_atomic_op("add %[newval], %[oldval], %[oparg]",
				  ret, oldval, uaddr, oparg);
		break;
	case FUTEX_OP_OR:
		__futex_atomic_op("or %[newval], %[oldval], %[oparg]",
				  ret, oldval, uaddr, oparg);
		break;
	case FUTEX_OP_ANDN:
		__futex_atomic_op("and %[newval], %[oldval], %[oparg]",
				  ret, oldval, uaddr, ~oparg);
		break;
	case FUTEX_OP_XOR:
		__futex_atomic_op("xor %[newval], %[oldval], %[oparg]",
				  ret, oldval, uaddr, oparg);
		break;
	default:
		ret = -ENOSYS;
	}

	pagefault_enable();

	if (!ret)
		*oval = oldval;

	return ret;
#else
	return -ENOSYS;
#endif
}

static inline int
futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
			      u32 oldval, u32 newval)
{
#if XCHAL_HAVE_S32C1I || XCHAL_HAVE_EXCLUSIVE
	unsigned long tmp;
	int ret = 0;

	if (!access_ok(uaddr, sizeof(u32)))
		return -EFAULT;

	__asm__ __volatile__ (
	"	# futex_atomic_cmpxchg_inatomic\n"
#if XCHAL_HAVE_EXCLUSIVE
	"1:	l32ex	%[tmp], %[addr]\n"
	"	s32i	%[tmp], %[uval], 0\n"
	"	bne	%[tmp], %[oldval], 2f\n"
	"	mov	%[tmp], %[newval]\n"
	"3:	s32ex	%[tmp], %[addr]\n"
	"	getex	%[tmp]\n"
	"	beqz	%[tmp], 1b\n"
#elif XCHAL_HAVE_S32C1I
	"	wsr	%[oldval], scompare1\n"
	"1:	s32c1i	%[newval], %[addr], 0\n"
	"	s32i	%[newval], %[uval], 0\n"
#endif
	"2:\n"
	"	.section .fixup,\"ax\"\n"
	"	.align 4\n"
	"	.literal_position\n"
	"4:	movi	%[tmp], 2b\n"
	"	movi	%[ret], %[fault]\n"
	"	jx	%[tmp]\n"
	"	.previous\n"
	"	.section __ex_table,\"a\"\n"
	"	.long 1b, 4b\n"
#if XCHAL_HAVE_EXCLUSIVE
	"	.long 3b, 4b\n"
#endif
	"	.previous\n"
	: [ret] "+r" (ret), [newval] "+r" (newval), [tmp] "=&r" (tmp)
	: [addr] "r" (uaddr), [oldval] "r" (oldval), [uval] "r" (uval),
	  [fault] "I" (-EFAULT)
	: "memory");

	return ret;
#else
	return -ENOSYS;
#endif
}

#endif /* _ASM_XTENSA_FUTEX_H */