futex.h
3.2 KB
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
/*
* 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
#ifdef __KERNEL__
#include <linux/futex.h>
#include <linux/uaccess.h>
#include <linux/errno.h>
#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \
__asm__ __volatile( \
"1: l32i %0, %2, 0\n" \
insn "\n" \
" wsr %0, scompare1\n" \
"2: s32c1i %1, %2, 0\n" \
" bne %1, %0, 1b\n" \
" movi %1, 0\n" \
"3:\n" \
" .section .fixup,\"ax\"\n" \
" .align 4\n" \
"4: .long 3b\n" \
"5: l32r %0, 4b\n" \
" movi %1, %3\n" \
" jx %0\n" \
" .previous\n" \
" .section __ex_table,\"a\"\n" \
" .long 1b,5b,2b,5b\n" \
" .previous\n" \
: "=&r" (oldval), "=&r" (ret) \
: "r" (uaddr), "I" (-EFAULT), "r" (oparg) \
: "memory")
static inline int futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr)
{
int op = (encoded_op >> 28) & 7;
int cmp = (encoded_op >> 24) & 15;
int oparg = (encoded_op << 8) >> 20;
int cmparg = (encoded_op << 20) >> 20;
int oldval = 0, ret;
if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
oparg = 1 << oparg;
if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
return -EFAULT;
#if !XCHAL_HAVE_S32C1I
return -ENOSYS;
#endif
pagefault_disable();
switch (op) {
case FUTEX_OP_SET:
__futex_atomic_op("mov %1, %4", ret, oldval, uaddr, oparg);
break;
case FUTEX_OP_ADD:
__futex_atomic_op("add %1, %0, %4", ret, oldval, uaddr,
oparg);
break;
case FUTEX_OP_OR:
__futex_atomic_op("or %1, %0, %4", ret, oldval, uaddr,
oparg);
break;
case FUTEX_OP_ANDN:
__futex_atomic_op("and %1, %0, %4", ret, oldval, uaddr,
~oparg);
break;
case FUTEX_OP_XOR:
__futex_atomic_op("xor %1, %0, %4", ret, oldval, uaddr,
oparg);
break;
default:
ret = -ENOSYS;
}
pagefault_enable();
if (ret)
return ret;
switch (cmp) {
case FUTEX_OP_CMP_EQ: return (oldval == cmparg);
case FUTEX_OP_CMP_NE: return (oldval != cmparg);
case FUTEX_OP_CMP_LT: return (oldval < cmparg);
case FUTEX_OP_CMP_GE: return (oldval >= cmparg);
case FUTEX_OP_CMP_LE: return (oldval <= cmparg);
case FUTEX_OP_CMP_GT: return (oldval > cmparg);
}
return -ENOSYS;
}
static inline int
futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
u32 oldval, u32 newval)
{
int ret = 0;
u32 prev;
if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
return -EFAULT;
#if !XCHAL_HAVE_S32C1I
return -ENOSYS;
#endif
__asm__ __volatile__ (
" # futex_atomic_cmpxchg_inatomic\n"
"1: l32i %1, %3, 0\n"
" mov %0, %5\n"
" wsr %1, scompare1\n"
"2: s32c1i %0, %3, 0\n"
"3:\n"
" .section .fixup,\"ax\"\n"
" .align 4\n"
"4: .long 3b\n"
"5: l32r %1, 4b\n"
" movi %0, %6\n"
" jx %1\n"
" .previous\n"
" .section __ex_table,\"a\"\n"
" .long 1b,5b,2b,5b\n"
" .previous\n"
: "+r" (ret), "=&r" (prev), "+m" (*uaddr)
: "r" (uaddr), "r" (oldval), "r" (newval), "I" (-EFAULT)
: "memory");
*uval = prev;
return ret;
}
#endif /* __KERNEL__ */
#endif /* _ASM_XTENSA_FUTEX_H */