1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
4 */
5 #ifndef _ASM_FUTEX_H
6 #define _ASM_FUTEX_H
7
8 #include <linux/futex.h>
9 #include <linux/uaccess.h>
10 #include <asm/asm-extable.h>
11 #include <asm/barrier.h>
12 #include <asm/errno.h>
13
14 #define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \
15 { \
16 __asm__ __volatile__( \
17 "1: ll.w %1, %4 # __futex_atomic_op\n" \
18 " " insn " \n" \
19 "2: sc.w $t0, %2 \n" \
20 " beqz $t0, 1b \n" \
21 "3: \n" \
22 _ASM_EXTABLE_UACCESS_ERR(1b, 3b, %0) \
23 _ASM_EXTABLE_UACCESS_ERR(2b, 3b, %0) \
24 : "=r" (ret), "=&r" (oldval), \
25 "=ZC" (*uaddr) \
26 : "" (0), "ZC" (*uaddr), "Jr" (oparg) \
27 : "memory", "t0"); \
28 }
29
30 static inline int
31 arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *uaddr)
32 {
33 int oldval = 0, ret = 0;
34
35 pagefault_disable();
36
37 switch (op) {
38 case FUTEX_OP_SET:
39 __futex_atomic_op("move $t0, %z5", ret, oldval, uaddr, oparg);
40 break;
41 case FUTEX_OP_ADD:
42 __futex_atomic_op("add.w $t0, %1, %z5", ret, oldval, uaddr, oparg);
43 break;
44 case FUTEX_OP_OR:
45 __futex_atomic_op("or $t0, %1, %z5", ret, oldval, uaddr, oparg);
46 break;
47 case FUTEX_OP_ANDN:
48 __futex_atomic_op("and $t0, %1, %z5", ret, oldval, uaddr, ~oparg);
49 break;
50 case FUTEX_OP_XOR:
51 __futex_atomic_op("xor $t0, %1, %z5", ret, oldval, uaddr, oparg);
52 break;
53 default:
54 ret = -ENOSYS;
55 }
56
57 pagefault_enable();
58
59 if (!ret)
60 *oval = oldval;
61
62 return ret;
63 }
64
65 static inline int
66 futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, u32 oldval, u32 newval)
67 {
68 int ret = 0;
69 u32 val = 0;
70
71 if (!access_ok(uaddr, sizeof(u32)))
72 return -EFAULT;
73
74 __asm__ __volatile__(
75 "# futex_atomic_cmpxchg_inatomic \n"
76 "1: ll.w %1, %3 \n"
77 " bne %1, %z4, 3f \n"
78 " move $t0, %z5 \n"
79 "2: sc.w $t0, %2 \n"
80 " beqz $t0, 1b \n"
81 "3: \n"
82 __WEAK_LLSC_MB
83 _ASM_EXTABLE_UACCESS_ERR(1b, 3b, %0)
84 _ASM_EXTABLE_UACCESS_ERR(2b, 3b, %0)
85 : "+r" (ret), "=&r" (val), "=ZC" (*uaddr)
86 : "ZC" (*uaddr), "Jr" (oldval), "Jr" (newval)
87 : "memory", "t0");
88
89 *uval = val;
90
91 return ret;
92 }
93
94 #endif /* _ASM_FUTEX_H */
95
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