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
|
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_PARISC_FUTEX_H
#define _ASM_PARISC_FUTEX_H
#include <linux/futex.h>
#include <linux/uaccess.h>
#include <asm/atomic.h>
#include <asm/errno.h>
/* The following has to match the LWS code in syscall.S. We have
sixteen four-word locks. */
static inline void
_futex_spin_lock(u32 __user *uaddr)
{
extern u32 lws_lock_start[];
long index = ((long)uaddr & 0x7f8) >> 1;
arch_spinlock_t *s = (arch_spinlock_t *)&lws_lock_start[index];
preempt_disable();
arch_spin_lock(s);
}
static inline void
_futex_spin_unlock(u32 __user *uaddr)
{
extern u32 lws_lock_start[];
long index = ((long)uaddr & 0x7f8) >> 1;
arch_spinlock_t *s = (arch_spinlock_t *)&lws_lock_start[index];
arch_spin_unlock(s);
preempt_enable();
}
static inline int
arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *uaddr)
{
int oldval, ret;
u32 tmp;
ret = -EFAULT;
_futex_spin_lock(uaddr);
if (unlikely(get_user(oldval, uaddr) != 0))
goto out_pagefault_enable;
ret = 0;
tmp = oldval;
switch (op) {
case FUTEX_OP_SET:
tmp = oparg;
break;
case FUTEX_OP_ADD:
tmp += oparg;
break;
case FUTEX_OP_OR:
tmp |= oparg;
break;
case FUTEX_OP_ANDN:
tmp &= ~oparg;
break;
case FUTEX_OP_XOR:
tmp ^= oparg;
break;
default:
ret = -ENOSYS;
}
if (ret == 0 && unlikely(put_user(tmp, uaddr) != 0))
ret = -EFAULT;
out_pagefault_enable:
_futex_spin_unlock(uaddr);
if (!ret)
*oval = oldval;
return ret;
}
static inline int
futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
u32 oldval, u32 newval)
{
u32 val;
/* futex.c wants to do a cmpxchg_inatomic on kernel NULL, which is
* our gateway page, and causes no end of trouble...
*/
if (uaccess_kernel() && !uaddr)
return -EFAULT;
if (!access_ok(uaddr, sizeof(u32)))
return -EFAULT;
/* HPPA has no cmpxchg in hardware and therefore the
* best we can do here is use an array of locks. The
* lock selected is based on a hash of the userspace
* address. This should scale to a couple of CPUs.
*/
_futex_spin_lock(uaddr);
if (unlikely(get_user(val, uaddr) != 0)) {
_futex_spin_unlock(uaddr);
return -EFAULT;
}
if (val == oldval && unlikely(put_user(newval, uaddr) != 0)) {
_futex_spin_unlock(uaddr);
return -EFAULT;
}
*uval = val;
_futex_spin_unlock(uaddr);
return 0;
}
#endif /*_ASM_PARISC_FUTEX_H*/
|
