1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ASM_POWERPC_FUTEX_H
3 #define _ASM_POWERPC_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/synch.h>
11
12 #define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \
13 __asm__ __volatile ( \
14 PPC_ATOMIC_ENTRY_BARRIER \
15 "1: lwarx %0,0,%2\n" \
16 insn \
17 "2: stwcx. %1,0,%2\n" \
18 "bne- 1b\n" \
19 PPC_ATOMIC_EXIT_BARRIER \
20 "li %1,0\n" \
21 "3: .section .fixup,\"ax\"\n" \
22 "4: li %1,%3\n" \
23 "b 3b\n" \
24 ".previous\n" \
25 EX_TABLE(1b, 4b) \
26 EX_TABLE(2b, 4b) \
27 : "=&r" (oldval), "=&r" (ret) \
28 : "b" (uaddr), "i" (-EFAULT), "r" (oparg) \
29 : "cr0", "memory")
30
31 static inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval,
32 u32 __user *uaddr)
33 {
34 int oldval = 0, ret;
35
36 if (!user_access_begin(uaddr, sizeof(u32)))
37 return -EFAULT;
38
39 switch (op) {
40 case FUTEX_OP_SET:
41 __futex_atomic_op("mr %1,%4\n", ret, oldval, uaddr, oparg);
42 break;
43 case FUTEX_OP_ADD:
44 __futex_atomic_op("add %1,%0,%4\n", ret, oldval, uaddr, oparg);
45 break;
46 case FUTEX_OP_OR:
47 __futex_atomic_op("or %1,%0,%4\n", ret, oldval, uaddr, oparg);
48 break;
49 case FUTEX_OP_ANDN:
50 __futex_atomic_op("andc %1,%0,%4\n", ret, oldval, uaddr, oparg);
51 break;
52 case FUTEX_OP_XOR:
53 __futex_atomic_op("xor %1,%0,%4\n", ret, oldval, uaddr, oparg);
54 break;
55 default:
56 ret = -ENOSYS;
57 }
58 user_access_end();
59
60 *oval = oldval;
61
62 return ret;
63 }
64
65 static inline int
66 futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
67 u32 oldval, u32 newval)
68 {
69 int ret = 0;
70 u32 prev;
71
72 if (!user_access_begin(uaddr, sizeof(u32)))
73 return -EFAULT;
74
75 __asm__ __volatile__ (
76 PPC_ATOMIC_ENTRY_BARRIER
77 "1: lwarx %1,0,%3 # futex_atomic_cmpxchg_inatomic\n\
78 cmpw 0,%1,%4\n\
79 bne- 3f\n"
80 "2: stwcx. %5,0,%3\n\
81 bne- 1b\n"
82 PPC_ATOMIC_EXIT_BARRIER
83 "3: .section .fixup,\"ax\"\n\
84 4: li %0,%6\n\
85 b 3b\n\
86 .previous\n"
87 EX_TABLE(1b, 4b)
88 EX_TABLE(2b, 4b)
89 : "+r" (ret), "=&r" (prev), "+m" (*uaddr)
90 : "r" (uaddr), "r" (oldval), "r" (newval), "i" (-EFAULT)
91 : "cc", "memory");
92
93 user_access_end();
94
95 *uval = prev;
96
97 return ret;
98 }
99
100 #endif /* __KERNEL__ */
101 #endif /* _ASM_POWERPC_FUTEX_H */
102
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