1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _ASM_HEXAGON_FUTEX_H
3#define _ASM_HEXAGON_FUTEX_H
4
5#ifdef __KERNEL__
6
7#include <linux/futex.h>
8#include <linux/uaccess.h>
9#include <asm/errno.h>
10
11/* XXX TODO-- need to add sync barriers! */
12
13#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \
14	__asm__ __volatile( \
15	"1: %0 = memw_locked(%3);\n" \
16	    /* For example: %1 = %4 */ \
17	    insn \
18	"2: memw_locked(%3,p2) = %1;\n" \
19	"   if (!p2) jump 1b;\n" \
20	"   %1 = #0;\n" \
21	"3:\n" \
22	".section .fixup,\"ax\"\n" \
23	"4: %1 = #%5;\n" \
24	"   jump ##3b\n" \
25	".previous\n" \
26	".section __ex_table,\"a\"\n" \
27	".long 1b,4b,2b,4b\n" \
28	".previous\n" \
29	: "=&r" (oldval), "=&r" (ret), "+m" (*uaddr) \
30	: "r" (uaddr), "r" (oparg), "i" (-EFAULT) \
31	: "p2", "memory")
32
33
34static inline int
35arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *uaddr)
36{
37	int oldval = 0, ret;
38
39	if (!access_ok(uaddr, sizeof(u32)))
40		return -EFAULT;
41
42	switch (op) {
43	case FUTEX_OP_SET:
44		__futex_atomic_op("%1 = %4\n", ret, oldval, uaddr, oparg);
45		break;
46	case FUTEX_OP_ADD:
47		__futex_atomic_op("%1 = add(%0,%4)\n", ret, oldval, uaddr,
48				  oparg);
49		break;
50	case FUTEX_OP_OR:
51		__futex_atomic_op("%1 = or(%0,%4)\n", ret, oldval, uaddr,
52				  oparg);
53		break;
54	case FUTEX_OP_ANDN:
55		__futex_atomic_op("%1 = not(%4); %1 = and(%0,%1)\n", ret,
56				  oldval, uaddr, oparg);
57		break;
58	case FUTEX_OP_XOR:
59		__futex_atomic_op("%1 = xor(%0,%4)\n", ret, oldval, uaddr,
60				  oparg);
61		break;
62	default:
63		ret = -ENOSYS;
64	}
65
66	if (!ret)
67		*oval = oldval;
68
69	return ret;
70}
71
72static inline int
73futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, u32 oldval,
74			      u32 newval)
75{
76	int prev;
77	int ret;
78
79	if (!access_ok(uaddr, sizeof(u32)))
80		return -EFAULT;
81
82	__asm__ __volatile__ (
83	"1: %1 = memw_locked(%3)\n"
84	"   {\n"
85	"      p2 = cmp.eq(%1,%4)\n"
86	"      if (!p2.new) jump:NT 3f\n"
87	"   }\n"
88	"2: memw_locked(%3,p2) = %5\n"
89	"   if (!p2) jump 1b\n"
90	"3:\n"
91	".section .fixup,\"ax\"\n"
92	"4: %0 = #%6\n"
93	"   jump ##3b\n"
94	".previous\n"
95	".section __ex_table,\"a\"\n"
96	".long 1b,4b,2b,4b\n"
97	".previous\n"
98	: "+r" (ret), "=&r" (prev), "+m" (*uaddr)
99	: "r" (uaddr), "r" (oldval), "r" (newval), "i"(-EFAULT)
100	: "p2", "memory");
101
102	*uval = prev;
103	return ret;
104}
105
106#endif /* __KERNEL__ */
107#endif /* _ASM_HEXAGON_FUTEX_H */
108