1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ASM_FUTEX_H
3 #define _ASM_FUTEX_H
4
5 #include <linux/futex.h>
6 #include <linux/uaccess.h>
7 #include <asm/errno.h>
8
9 #define __futex_atomic_op1(insn, ret, oldval, uaddr, oparg) \
10 do { \
11 register unsigned long r8 __asm ("r8") = 0; \
12 __asm__ __volatile__( \
13 " mf;; \n" \
14 "[1:] " insn ";; \n" \
15 " .xdata4 \"__ex_table\", 1b-., 2f-. \n" \
16 "[2:]" \
17 : "+r" (r8), "=r" (oldval) \
18 : "r" (uaddr), "r" (oparg) \
19 : "memory"); \
20 ret = r8; \
21 } while (0)
22
23 #define __futex_atomic_op2(insn, ret, oldval, uaddr, oparg) \
24 do { \
25 register unsigned long r8 __asm ("r8") = 0; \
26 int val, newval; \
27 do { \
28 __asm__ __volatile__( \
29 " mf;; \n" \
30 "[1:] ld4 %3=[%4];; \n" \
31 " mov %2=%3 \n" \
32 insn ";; \n" \
33 " mov ar.ccv=%2;; \n" \
34 "[2:] cmpxchg4.acq %1=[%4],%3,ar.ccv;; \n" \
35 " .xdata4 \"__ex_table\", 1b-., 3f-.\n" \
36 " .xdata4 \"__ex_table\", 2b-., 3f-.\n" \
37 "[3:]" \
38 : "+r" (r8), "=r" (val), "=&r" (oldval), \
39 "=&r" (newval) \
40 : "r" (uaddr), "r" (oparg) \
41 : "memory"); \
42 if (unlikely (r8)) \
43 break; \
44 } while (unlikely (val != oldval)); \
45 ret = r8; \
46 } while (0)
47
48 static inline int
49 arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *uaddr)
50 {
51 int oldval = 0, ret;
52
53 pagefault_disable();
54
55 switch (op) {
56 case FUTEX_OP_SET:
57 __futex_atomic_op1("xchg4 %1=[%2],%3", ret, oldval, uaddr,
58 oparg);
59 break;
60 case FUTEX_OP_ADD:
61 __futex_atomic_op2("add %3=%3,%5", ret, oldval, uaddr, oparg);
62 break;
63 case FUTEX_OP_OR:
64 __futex_atomic_op2("or %3=%3,%5", ret, oldval, uaddr, oparg);
65 break;
66 case FUTEX_OP_ANDN:
67 __futex_atomic_op2("and %3=%3,%5", ret, oldval, uaddr,
68 ~oparg);
69 break;
70 case FUTEX_OP_XOR:
71 __futex_atomic_op2("xor %3=%3,%5", ret, oldval, uaddr, oparg);
72 break;
73 default:
74 ret = -ENOSYS;
75 }
76
77 pagefault_enable();
78
79 if (!ret)
80 *oval = oldval;
81
82 return ret;
83 }
84
85 static inline int
86 futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
87 u32 oldval, u32 newval)
88 {
89 if (!access_ok(uaddr, sizeof(u32)))
90 return -EFAULT;
91
92 {
93 register unsigned long r8 __asm ("r8") = 0;
94 unsigned long prev;
95 __asm__ __volatile__(
96 " mf;; \n"
97 " mov ar.ccv=%4;; \n"
98 "[1:] cmpxchg4.acq %1=[%2],%3,ar.ccv \n"
99 " .xdata4 \"__ex_table\", 1b-., 2f-. \n"
100 "[2:]"
101 : "+r" (r8), "=&r" (prev)
102 : "r" (uaddr), "r" (newval),
103 "rO" ((long) (unsigned) oldval)
104 : "memory");
105 *uval = prev;
106 return r8;
107 }
108 }
109
110 #endif /* _ASM_FUTEX_H */