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gerrit.nordix.org / codeaurora / cp-linux / 8d8f6542b666daf5e87de156590e635c2c4da0c0 / . / arch / parisc / include / asm / futex.h
blob: 49df14805a9b44bba6857ec4138fe62164e935ab [file] [log] [blame]
Kyle Swenson8d8f6542021-03-15 11:02:55 -0600[diff] [blame^]1#ifndef _ASM_PARISC_FUTEX_H
2#define _ASM_PARISC_FUTEX_H
3
4#ifdef __KERNEL__
5
6#include <linux/futex.h>
7#include <linux/uaccess.h>
8#include <asm/atomic.h>
9#include <asm/errno.h>
10
11/* The following has to match the LWS code in syscall.S. We have
12 sixteen four-word locks. */
13
14static inline void
15_futex_spin_lock_irqsave(u32 __user *uaddr, unsigned long int *flags)
16{
17 extern u32 lws_lock_start[];
18 long index = ((long)uaddr & 0xf0) >> 2;
19 arch_spinlock_t *s = (arch_spinlock_t *)&lws_lock_start[index];
20 local_irq_save(*flags);
21 arch_spin_lock(s);
22}
23
24static inline void
25_futex_spin_unlock_irqrestore(u32 __user *uaddr, unsigned long int *flags)
26{
27 extern u32 lws_lock_start[];
28 long index = ((long)uaddr & 0xf0) >> 2;
29 arch_spinlock_t *s = (arch_spinlock_t *)&lws_lock_start[index];
30 arch_spin_unlock(s);
31 local_irq_restore(*flags);
32}
33
34static inline int
35futex_atomic_op_inuser (int encoded_op, u32 __user *uaddr)
36{
37 unsigned long int flags;
38 u32 val;
39 int op = (encoded_op >> 28) & 7;
40 int cmp = (encoded_op >> 24) & 15;
41 int oparg = (encoded_op << 8) >> 20;
42 int cmparg = (encoded_op << 20) >> 20;
43 int oldval = 0, ret;
44 if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
45 oparg = 1 << oparg;
46
47 if (!access_ok(VERIFY_WRITE, uaddr, sizeof(*uaddr)))
48 return -EFAULT;
49
50 pagefault_disable();
51
52 _futex_spin_lock_irqsave(uaddr, &flags);
53
54 switch (op) {
55 case FUTEX_OP_SET:
56 /* *(int *)UADDR2 = OPARG; */
57 ret = get_user(oldval, uaddr);
58 if (!ret)
59 ret = put_user(oparg, uaddr);
60 break;
61 case FUTEX_OP_ADD:
62 /* *(int *)UADDR2 += OPARG; */
63 ret = get_user(oldval, uaddr);
64 if (!ret) {
65 val = oldval + oparg;
66 ret = put_user(val, uaddr);
67 }
68 break;
69 case FUTEX_OP_OR:
70 /* *(int *)UADDR2 |= OPARG; */
71 ret = get_user(oldval, uaddr);
72 if (!ret) {
73 val = oldval | oparg;
74 ret = put_user(val, uaddr);
75 }
76 break;
77 case FUTEX_OP_ANDN:
78 /* *(int *)UADDR2 &= ~OPARG; */
79 ret = get_user(oldval, uaddr);
80 if (!ret) {
81 val = oldval & ~oparg;
82 ret = put_user(val, uaddr);
83 }
84 break;
85 case FUTEX_OP_XOR:
86 /* *(int *)UADDR2 ^= OPARG; */
87 ret = get_user(oldval, uaddr);
88 if (!ret) {
89 val = oldval ^ oparg;
90 ret = put_user(val, uaddr);
91 }
92 break;
93 default:
94 ret = -ENOSYS;
95 }
96
97 _futex_spin_unlock_irqrestore(uaddr, &flags);
98
99 pagefault_enable();
100
101 if (!ret) {
102 switch (cmp) {
103 case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break;
104 case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break;
105 case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break;
106 case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break;
107 case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break;
108 case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break;
109 default: ret = -ENOSYS;
110 }
111 }
112 return ret;
113}
114
115/* Non-atomic version */
116static inline int
117futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
118 u32 oldval, u32 newval)
119{
120 int ret;
121 u32 val;
122 unsigned long flags;
123
124 /* futex.c wants to do a cmpxchg_inatomic on kernel NULL, which is
125 * our gateway page, and causes no end of trouble...
126 */
127 if (segment_eq(KERNEL_DS, get_fs()) && !uaddr)
128 return -EFAULT;
129
130 if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
131 return -EFAULT;
132
133 /* HPPA has no cmpxchg in hardware and therefore the
134 * best we can do here is use an array of locks. The
135 * lock selected is based on a hash of the userspace
136 * address. This should scale to a couple of CPUs.
137 */
138
139 _futex_spin_lock_irqsave(uaddr, &flags);
140
141 ret = get_user(val, uaddr);
142
143 if (!ret && val == oldval)
144 ret = put_user(newval, uaddr);
145
146 *uval = val;
147
148 _futex_spin_unlock_irqrestore(uaddr, &flags);
149
150 return ret;
151}
152
153#endif /*__KERNEL__*/
154#endif /*_ASM_PARISC_FUTEX_H*/