1 /* SPDX-License-Identifier: GPL-2.0 */ 1
2 #ifndef _ASM_X86_FUTEX_H
3 #define _ASM_X86_FUTEX_H
4
5 #ifdef __KERNEL__
6
7 #include <linux/futex.h>
8 #include <linux/uaccess.h>
9
10 #include <asm/asm.h>
11 #include <asm/errno.h>
12 #include <asm/processor.h>
13 #include <asm/smap.h>
14
15 #define unsafe_atomic_op1(insn, oval, uaddr, o
16 do {
17 int oldval = 0, ret;
18 asm volatile("1:\t" insn "\n"
19 "2:\n"
20 _ASM_EXTABLE_TYPE_REG(1b,
21 : "=r" (oldval), "=r" (re
22 : "" (oparg), "1" (0));
23 if (ret)
24 goto label;
25 *oval = oldval;
26 } while(0)
27
28
29 #define unsafe_atomic_op2(insn, oval, uaddr, o
30 do {
31 int oldval = 0, ret, tem;
32 asm volatile("1:\tmovl %2, %0\n"
33 "2:\tmovl\t%0, %3\n"
34 "\t" insn "\n"
35 "3:\t" LOCK_PREFIX "cmpxc
36 "\tjnz\t2b\n"
37 "4:\n"
38 _ASM_EXTABLE_TYPE_REG(1b,
39 _ASM_EXTABLE_TYPE_REG(3b,
40 : "=&a" (oldval), "=&r" (
41 "+m" (*uaddr), "=&r" (t
42 : "r" (oparg), "1" (0));
43 if (ret)
44 goto label;
45 *oval = oldval;
46 } while(0)
47
48 static __always_inline int arch_futex_atomic_o
49 u32 __user *uaddr)
50 {
51 if (!user_access_begin(uaddr, sizeof(u
52 return -EFAULT;
53
54 switch (op) {
55 case FUTEX_OP_SET:
56 unsafe_atomic_op1("xchgl %0, %
57 break;
58 case FUTEX_OP_ADD:
59 unsafe_atomic_op1(LOCK_PREFIX
60 uaddr, opar
61 break;
62 case FUTEX_OP_OR:
63 unsafe_atomic_op2("orl %4, %3"
64 break;
65 case FUTEX_OP_ANDN:
66 unsafe_atomic_op2("andl %4, %3
67 break;
68 case FUTEX_OP_XOR:
69 unsafe_atomic_op2("xorl %4, %3
70 break;
71 default:
72 user_access_end();
73 return -ENOSYS;
74 }
75 user_access_end();
76 return 0;
77 Efault:
78 user_access_end();
79 return -EFAULT;
80 }
81
82 static inline int futex_atomic_cmpxchg_inatomi
83
84 {
85 int ret = 0;
86
87 if (!user_access_begin(uaddr, sizeof(u
88 return -EFAULT;
89 asm volatile("\n"
90 "1:\t" LOCK_PREFIX "cmpxchgl %
91 "2:\n"
92 _ASM_EXTABLE_TYPE_REG(1b, 2b,
93 : "+r" (ret), "=a" (oldval), "
94 : "r" (newval), "1" (oldval)
95 : "memory"
96 );
97 user_access_end();
98 *uval = oldval;
99 return ret;
100 }
101
102 #endif
103 #endif /* _ASM_X86_FUTEX_H */
104
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