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/arch/alpha/include/asm/futex.h

http://github.com/mirrors/linux
C Header | 95 lines | 81 code | 13 blank | 1 comment | 4 complexity | 3c0c720418277dee06743921313d85c6 MD5 | raw file
 1/* SPDX-License-Identifier: GPL-2.0 */
 2#ifndef _ASM_ALPHA_FUTEX_H
 3#define _ASM_ALPHA_FUTEX_H
 4
 5#ifdef __KERNEL__
 6
 7#include <linux/futex.h>
 8#include <linux/uaccess.h>
 9#include <asm/errno.h>
10#include <asm/barrier.h>
11
12#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg)	\
13	__asm__ __volatile__(					\
14		__ASM_SMP_MB					\
15	"1:	ldl_l	%0,0(%2)\n"				\
16		insn						\
17	"2:	stl_c	%1,0(%2)\n"				\
18	"	beq	%1,4f\n"				\
19	"	mov	$31,%1\n"				\
20	"3:	.subsection 2\n"				\
21	"4:	br	1b\n"					\
22	"	.previous\n"					\
23	EXC(1b,3b,$31,%1)					\
24	EXC(2b,3b,$31,%1)					\
25	:	"=&r" (oldval), "=&r"(ret)			\
26	:	"r" (uaddr), "r"(oparg)				\
27	:	"memory")
28
29static inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval,
30		u32 __user *uaddr)
31{
32	int oldval = 0, ret;
33
34	if (!access_ok(uaddr, sizeof(u32)))
35		return -EFAULT;
36
37	switch (op) {
38	case FUTEX_OP_SET:
39		__futex_atomic_op("mov %3,%1\n", ret, oldval, uaddr, oparg);
40		break;
41	case FUTEX_OP_ADD:
42		__futex_atomic_op("addl %0,%3,%1\n", ret, oldval, uaddr, oparg);
43		break;
44	case FUTEX_OP_OR:
45		__futex_atomic_op("or %0,%3,%1\n", ret, oldval, uaddr, oparg);
46		break;
47	case FUTEX_OP_ANDN:
48		__futex_atomic_op("andnot %0,%3,%1\n", ret, oldval, uaddr, oparg);
49		break;
50	case FUTEX_OP_XOR:
51		__futex_atomic_op("xor %0,%3,%1\n", ret, oldval, uaddr, oparg);
52		break;
53	default:
54		ret = -ENOSYS;
55	}
56
57	if (!ret)
58		*oval = oldval;
59
60	return ret;
61}
62
63static inline int
64futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
65			      u32 oldval, u32 newval)
66{
67	int ret = 0, cmp;
68	u32 prev;
69
70	if (!access_ok(uaddr, sizeof(u32)))
71		return -EFAULT;
72
73	__asm__ __volatile__ (
74		__ASM_SMP_MB
75	"1:	ldl_l	%1,0(%3)\n"
76	"	cmpeq	%1,%4,%2\n"
77	"	beq	%2,3f\n"
78	"	mov	%5,%2\n"
79	"2:	stl_c	%2,0(%3)\n"
80	"	beq	%2,4f\n"
81	"3:	.subsection 2\n"
82	"4:	br	1b\n"
83	"	.previous\n"
84	EXC(1b,3b,$31,%0)
85	EXC(2b,3b,$31,%0)
86	:	"+r"(ret), "=&r"(prev), "=&r"(cmp)
87	:	"r"(uaddr), "r"((long)(int)oldval), "r"(newval)
88	:	"memory");
89
90	*uval = prev;
91	return ret;
92}
93
94#endif /* __KERNEL__ */
95#endif /* _ASM_ALPHA_FUTEX_H */