1/* SPDX-License-Identifier: GPL-2.0 */
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 __futex_atomic_op1(insn, ret, oldval, uaddr, oparg) \
16 asm volatile("\t" ASM_STAC "\n" \
17 "1:\t" insn "\n" \
18 "2:\t" ASM_CLAC "\n" \
19 "\t.section .fixup,\"ax\"\n" \
20 "3:\tmov\t%3, %1\n" \
21 "\tjmp\t2b\n" \
22 "\t.previous\n" \
23 _ASM_EXTABLE_UA(1b, 3b) \
24 : "=r" (oldval), "=r" (ret), "+m" (*uaddr) \
25 : "i" (-EFAULT), "0" (oparg), "1" (0))
26
27#define __futex_atomic_op2(insn, ret, oldval, uaddr, oparg) \
28 asm volatile("\t" ASM_STAC "\n" \
29 "1:\tmovl %2, %0\n" \
30 "\tmovl\t%0, %3\n" \
31 "\t" insn "\n" \
32 "2:\t" LOCK_PREFIX "cmpxchgl %3, %2\n" \
33 "\tjnz\t1b\n" \
34 "3:\t" ASM_CLAC "\n" \
35 "\t.section .fixup,\"ax\"\n" \
36 "4:\tmov\t%5, %1\n" \
37 "\tjmp\t3b\n" \
38 "\t.previous\n" \
39 _ASM_EXTABLE_UA(1b, 4b) \
40 _ASM_EXTABLE_UA(2b, 4b) \
41 : "=&a" (oldval), "=&r" (ret), \
42 "+m" (*uaddr), "=&r" (tem) \
43 : "r" (oparg), "i" (-EFAULT), "1" (0))
44
45static inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval,
46 u32 __user *uaddr)
47{
48 int oldval = 0, ret, tem;
49
50 pagefault_disable();
51
52 switch (op) {
53 case FUTEX_OP_SET:
54 __futex_atomic_op1("xchgl %0, %2", ret, oldval, uaddr, oparg);
55 break;
56 case FUTEX_OP_ADD:
57 __futex_atomic_op1(LOCK_PREFIX "xaddl %0, %2", ret, oldval,
58 uaddr, oparg);
59 break;
60 case FUTEX_OP_OR:
61 __futex_atomic_op2("orl %4, %3", ret, oldval, uaddr, oparg);
62 break;
63 case FUTEX_OP_ANDN:
64 __futex_atomic_op2("andl %4, %3", ret, oldval, uaddr, ~oparg);
65 break;
66 case FUTEX_OP_XOR:
67 __futex_atomic_op2("xorl %4, %3", ret, oldval, uaddr, oparg);
68 break;
69 default:
70 ret = -ENOSYS;
71 }
72
73 pagefault_enable();
74
75 if (!ret)
76 *oval = oldval;
77
78 return ret;
79}
80
81static inline int futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
82 u32 oldval, u32 newval)
83{
84 return user_atomic_cmpxchg_inatomic(uval, uaddr, oldval, newval);
85}
86
87#endif
88#endif /* _ASM_X86_FUTEX_H */
89