1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3 * Atomic futex routines
4 *
5 * Based on the PowerPC implementataion
6 *
7 * Copyright (C) 2013 TangoTec Ltd.
8 *
9 * Baruch Siach <baruch@tkos.co.il>
10 */
11
12 #ifndef _ASM_XTENSA_FUTEX_H
13 #define _ASM_XTENSA_FUTEX_H
14
15 #include <linux/futex.h>
16 #include <linux/uaccess.h>
17 #include <linux/errno.h>
18
19 #define arch_futex_atomic_op_inuser arch_futex_atomic_op_inuser
20 #define futex_atomic_cmpxchg_inatomic futex_atomic_cmpxchg_inatomic
21 #include <asm-generic/futex.h>
22
23 #if XCHAL_HAVE_EXCLUSIVE
24 #define __futex_atomic_op(insn, ret, old, uaddr, arg) \
25 __asm__ __volatile( \
26 "1: l32ex %[oldval], %[addr]\n" \
27 insn "\n" \
28 "2: s32ex %[newval], %[addr]\n" \
29 " getex %[newval]\n" \
30 " beqz %[newval], 1b\n" \
31 " movi %[newval], 0\n" \
32 "3:\n" \
33 " .section .fixup,\"ax\"\n" \
34 " .align 4\n" \
35 " .literal_position\n" \
36 "5: movi %[oldval], 3b\n" \
37 " movi %[newval], %[fault]\n" \
38 " jx %[oldval]\n" \
39 " .previous\n" \
40 " .section __ex_table,\"a\"\n" \
41 " .long 1b, 5b, 2b, 5b\n" \
42 " .previous\n" \
43 : [oldval] "=&r" (old), [newval] "=&r" (ret) \
44 : [addr] "r" (uaddr), [oparg] "r" (arg), \
45 [fault] "I" (-EFAULT) \
46 : "memory")
47 #elif XCHAL_HAVE_S32C1I
48 #define __futex_atomic_op(insn, ret, old, uaddr, arg) \
49 __asm__ __volatile( \
50 "1: l32i %[oldval], %[mem]\n" \
51 insn "\n" \
52 " wsr %[oldval], scompare1\n" \
53 "2: s32c1i %[newval], %[mem]\n" \
54 " bne %[newval], %[oldval], 1b\n" \
55 " movi %[newval], 0\n" \
56 "3:\n" \
57 " .section .fixup,\"ax\"\n" \
58 " .align 4\n" \
59 " .literal_position\n" \
60 "5: movi %[oldval], 3b\n" \
61 " movi %[newval], %[fault]\n" \
62 " jx %[oldval]\n" \
63 " .previous\n" \
64 " .section __ex_table,\"a\"\n" \
65 " .long 1b, 5b, 2b, 5b\n" \
66 " .previous\n" \
67 : [oldval] "=&r" (old), [newval] "=&r" (ret), \
68 [mem] "+m" (*(uaddr)) \
69 : [oparg] "r" (arg), [fault] "I" (-EFAULT) \
70 : "memory")
71 #endif
72
73 static inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval,
74 u32 __user *uaddr)
75 {
76 #if XCHAL_HAVE_S32C1I || XCHAL_HAVE_EXCLUSIVE
77 int oldval = 0, ret;
78
79 if (!access_ok(uaddr, sizeof(u32)))
80 return -EFAULT;
81
82 switch (op) {
83 case FUTEX_OP_SET:
84 __futex_atomic_op("mov %[newval], %[oparg]",
85 ret, oldval, uaddr, oparg);
86 break;
87 case FUTEX_OP_ADD:
88 __futex_atomic_op("add %[newval], %[oldval], %[oparg]",
89 ret, oldval, uaddr, oparg);
90 break;
91 case FUTEX_OP_OR:
92 __futex_atomic_op("or %[newval], %[oldval], %[oparg]",
93 ret, oldval, uaddr, oparg);
94 break;
95 case FUTEX_OP_ANDN:
96 __futex_atomic_op("and %[newval], %[oldval], %[oparg]",
97 ret, oldval, uaddr, ~oparg);
98 break;
99 case FUTEX_OP_XOR:
100 __futex_atomic_op("xor %[newval], %[oldval], %[oparg]",
101 ret, oldval, uaddr, oparg);
102 break;
103 default:
104 ret = -ENOSYS;
105 }
106
107 if (!ret)
108 *oval = oldval;
109
110 return ret;
111 #else
112 return futex_atomic_op_inuser_local(op, oparg, oval, uaddr);
113 #endif
114 }
115
116 static inline int
117 futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
118 u32 oldval, u32 newval)
119 {
120 #if XCHAL_HAVE_S32C1I || XCHAL_HAVE_EXCLUSIVE
121 unsigned long tmp;
122 int ret = 0;
123
124 if (!access_ok(uaddr, sizeof(u32)))
125 return -EFAULT;
126
127 __asm__ __volatile__ (
128 " # futex_atomic_cmpxchg_inatomic\n"
129 #if XCHAL_HAVE_EXCLUSIVE
130 "1: l32ex %[tmp], %[addr]\n"
131 " s32i %[tmp], %[uval], 0\n"
132 " bne %[tmp], %[oldval], 2f\n"
133 " mov %[tmp], %[newval]\n"
134 "3: s32ex %[tmp], %[addr]\n"
135 " getex %[tmp]\n"
136 " beqz %[tmp], 1b\n"
137 #elif XCHAL_HAVE_S32C1I
138 " wsr %[oldval], scompare1\n"
139 "1: s32c1i %[newval], %[addr], 0\n"
140 " s32i %[newval], %[uval], 0\n"
141 #endif
142 "2:\n"
143 " .section .fixup,\"ax\"\n"
144 " .align 4\n"
145 " .literal_position\n"
146 "4: movi %[tmp], 2b\n"
147 " movi %[ret], %[fault]\n"
148 " jx %[tmp]\n"
149 " .previous\n"
150 " .section __ex_table,\"a\"\n"
151 " .long 1b, 4b\n"
152 #if XCHAL_HAVE_EXCLUSIVE
153 " .long 3b, 4b\n"
154 #endif
155 " .previous\n"
156 : [ret] "+r" (ret), [newval] "+r" (newval), [tmp] "=&r" (tmp)
157 : [addr] "r" (uaddr), [oldval] "r" (oldval), [uval] "r" (uval),
158 [fault] "I" (-EFAULT)
159 : "memory");
160
161 return ret;
162 #else
163 return futex_atomic_cmpxchg_inatomic_local(uval, uaddr, oldval, newval);
164 #endif
165 }
166
167 #endif /* _ASM_XTENSA_FUTEX_H */
168
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