tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _ASM_PARISC_FUTEX_H
3#define _ASM_PARISC_FUTEX_H
4
5#ifdef __KERNEL__
6
7#include <linux/futex.h>
8#include <linux/uaccess.h>
9#include <asm/atomic.h>
10#include <asm/errno.h>
11
12/* The following has to match the LWS code in syscall.S. We have
13 sixteen four-word locks. */
14
15static inline void
16_futex_spin_lock_irqsave(u32 __user *uaddr, unsigned long int *flags)
17{
18 extern u32 lws_lock_start[];
19 long index = ((long)uaddr & 0xf0) >> 2;
20 arch_spinlock_t *s = (arch_spinlock_t *)&lws_lock_start[index];
21 local_irq_save(*flags);
22 arch_spin_lock(s);
23}
24
25static inline void
26_futex_spin_unlock_irqrestore(u32 __user *uaddr, unsigned long int *flags)
27{
28 extern u32 lws_lock_start[];
29 long index = ((long)uaddr & 0xf0) >> 2;
30 arch_spinlock_t *s = (arch_spinlock_t *)&lws_lock_start[index];
31 arch_spin_unlock(s);
32 local_irq_restore(*flags);
33}
34
35static inline int
36arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *uaddr)
37{
38 unsigned long int flags;
39 int oldval, ret;
40 u32 tmp;
41
42 _futex_spin_lock_irqsave(uaddr, &flags);
43 pagefault_disable();
44
45 ret = -EFAULT;
46 if (unlikely(get_user(oldval, uaddr) != 0))
47 goto out_pagefault_enable;
48
49 ret = 0;
50 tmp = oldval;
51
52 switch (op) {
53 case FUTEX_OP_SET:
54 tmp = oparg;
55 break;
56 case FUTEX_OP_ADD:
57 tmp += oparg;
58 break;
59 case FUTEX_OP_OR:
60 tmp |= oparg;
61 break;
62 case FUTEX_OP_ANDN:
63 tmp &= ~oparg;
64 break;
65 case FUTEX_OP_XOR:
66 tmp ^= oparg;
67 break;
68 default:
69 ret = -ENOSYS;
70 }
71
72 if (ret == 0 && unlikely(put_user(tmp, uaddr) != 0))
73 ret = -EFAULT;
74
75out_pagefault_enable:
76 pagefault_enable();
77 _futex_spin_unlock_irqrestore(uaddr, &flags);
78
79 if (!ret)
80 *oval = oldval;
81
82 return ret;
83}
84
85static inline int
86futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
87 u32 oldval, u32 newval)
88{
89 u32 val;
90 unsigned long flags;
91
92 /* futex.c wants to do a cmpxchg_inatomic on kernel NULL, which is
93 * our gateway page, and causes no end of trouble...
94 */
95 if (uaccess_kernel() && !uaddr)
96 return -EFAULT;
97
98 if (!access_ok(uaddr, sizeof(u32)))
99 return -EFAULT;
100
101 /* HPPA has no cmpxchg in hardware and therefore the
102 * best we can do here is use an array of locks. The
103 * lock selected is based on a hash of the userspace
104 * address. This should scale to a couple of CPUs.
105 */
106
107 _futex_spin_lock_irqsave(uaddr, &flags);
108 if (unlikely(get_user(val, uaddr) != 0)) {
109 _futex_spin_unlock_irqrestore(uaddr, &flags);
110 return -EFAULT;
111 }
112
113 if (val == oldval && unlikely(put_user(newval, uaddr) != 0)) {
114 _futex_spin_unlock_irqrestore(uaddr, &flags);
115 return -EFAULT;
116 }
117
118 *uval = val;
119 _futex_spin_unlock_irqrestore(uaddr, &flags);
120
121 return 0;
122}
123
124#endif /*__KERNEL__*/
125#endif /*_ASM_PARISC_FUTEX_H*/