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/barrier.h>
11 #include <asm/errno.h>
12
13 #define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \
14 { \
15 __asm__ __volatile__( \
16 "1: ll.w %1, %4 # __futex_atomic_op\n" \
17 " " insn " \n" \
18 "2: sc.w $t0, %2 \n" \
19 " beqz $t0, 1b \n" \
20 "3: \n" \
21 " .section .fixup,\"ax\" \n" \
22 "4: li.w %0, %6 \n" \
23 " b 3b \n" \
24 " .previous \n" \
25 " .section __ex_table,\"a\" \n" \
26 " "__UA_ADDR "\t1b, 4b \n" \
27 " "__UA_ADDR "\t2b, 4b \n" \
28 " .previous \n" \
29 : "=r" (ret), "=&r" (oldval), \
30 "=ZC" (*uaddr) \
31 : "0" (0), "ZC" (*uaddr), "Jr" (oparg), \
32 "i" (-EFAULT) \
33 : "memory", "t0"); \
34 }
35
36 static inline int
arch_futex_atomic_op_inuser(int op,int oparg,int * oval,u32 __user * uaddr)37 arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *uaddr)
38 {
39 int oldval = 0, ret = 0;
40
41 pagefault_disable();
42
43 switch (op) {
44 case FUTEX_OP_SET:
45 __futex_atomic_op("move $t0, %z5", ret, oldval, uaddr, oparg);
46 break;
47 case FUTEX_OP_ADD:
48 __futex_atomic_op("add.w $t0, %1, %z5", ret, oldval, uaddr, oparg);
49 break;
50 case FUTEX_OP_OR:
51 __futex_atomic_op("or $t0, %1, %z5", ret, oldval, uaddr, oparg);
52 break;
53 case FUTEX_OP_ANDN:
54 __futex_atomic_op("and $t0, %1, %z5", ret, oldval, uaddr, ~oparg);
55 break;
56 case FUTEX_OP_XOR:
57 __futex_atomic_op("xor $t0, %1, %z5", ret, oldval, uaddr, oparg);
58 break;
59 default:
60 ret = -ENOSYS;
61 }
62
63 pagefault_enable();
64
65 if (!ret)
66 *oval = oldval;
67
68 return ret;
69 }
70
71 static inline int
futex_atomic_cmpxchg_inatomic(u32 * uval,u32 __user * uaddr,u32 oldval,u32 newval)72 futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, u32 oldval, u32 newval)
73 {
74 int ret = 0;
75 u32 val = 0;
76
77 if (!access_ok(uaddr, sizeof(u32)))
78 return -EFAULT;
79
80 __asm__ __volatile__(
81 "# futex_atomic_cmpxchg_inatomic \n"
82 "1: ll.w %1, %3 \n"
83 " bne %1, %z4, 3f \n"
84 " move $t0, %z5 \n"
85 "2: sc.w $t0, %2 \n"
86 " beqz $t0, 1b \n"
87 "3: \n"
88 __WEAK_LLSC_MB
89 " .section .fixup,\"ax\" \n"
90 "4: li.d %0, %6 \n"
91 " b 3b \n"
92 " .previous \n"
93 " .section __ex_table,\"a\" \n"
94 " "__UA_ADDR "\t1b, 4b \n"
95 " "__UA_ADDR "\t2b, 4b \n"
96 " .previous \n"
97 : "+r" (ret), "=&r" (val), "=ZC" (*uaddr)
98 : "ZC" (*uaddr), "Jr" (oldval), "Jr" (newval),
99 "i" (-EFAULT)
100 : "memory", "t0");
101
102 *uval = val;
103
104 return ret;
105 }
106
107 #endif /* _ASM_FUTEX_H */
108