1/* Copyright (C) 2005-2017 Free Software Foundation, Inc.
2 Contributed by Richard Henderson <rth@redhat.com>.
3
4 This file is part of the GNU Offloading and Multi Processing Library
5 (libgomp).
6
7 Libgomp is free software; you can redistribute it and/or modify it
8 under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3, or (at your option)
10 any later version.
11
12 Libgomp is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
14 FOR A PARTICULAR PURPOSE. See the GNU General Public License for
15 more details.
16
17 Under Section 7 of GPL version 3, you are granted additional
18 permissions described in the GCC Runtime Library Exception, version
19 3.1, as published by the Free Software Foundation.
20
21 You should have received a copy of the GNU General Public License and
22 a copy of the GCC Runtime Library Exception along with this program;
23 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
24 <http://www.gnu.org/licenses/>. */
25
26/* Provide target-specific access to the futex system call. */
27
28#ifdef __x86_64__
29# ifndef SYS_futex
30# define SYS_futex 202
31# endif
32
33static inline void
34futex_wait (int *addr, int val)
35{
36 long res;
37
38 register long r10 __asm__("%r10") = 0;
39 __asm volatile ("syscall"
40 : "=a" (res)
41 : "0" (SYS_futex), "D" (addr), "S" (gomp_futex_wait),
42 "d" (val), "r" (r10)
43 : "r11", "rcx", "memory");
44 if (__builtin_expect (res == -ENOSYS, 0))
45 {
46 gomp_futex_wait &= ~FUTEX_PRIVATE_FLAG;
47 gomp_futex_wake &= ~FUTEX_PRIVATE_FLAG;
48 __asm volatile ("syscall"
49 : "=a" (res)
50 : "0" (SYS_futex), "D" (addr), "S" (gomp_futex_wait),
51 "d" (val), "r" (r10)
52 : "r11", "rcx", "memory");
53 }
54}
55
56static inline void
57futex_wake (int *addr, int count)
58{
59 long res;
60
61 __asm volatile ("syscall"
62 : "=a" (res)
63 : "0" (SYS_futex), "D" (addr), "S" (gomp_futex_wake),
64 "d" (count)
65 : "r11", "rcx", "memory");
66 if (__builtin_expect (res == -ENOSYS, 0))
67 {
68 gomp_futex_wait &= ~FUTEX_PRIVATE_FLAG;
69 gomp_futex_wake &= ~FUTEX_PRIVATE_FLAG;
70 __asm volatile ("syscall"
71 : "=a" (res)
72 : "0" (SYS_futex), "D" (addr), "S" (gomp_futex_wake),
73 "d" (count)
74 : "r11", "rcx", "memory");
75 }
76}
77#else
78# ifndef SYS_futex
79# define SYS_futex 240
80# endif
81
82static inline void
83futex_wait (int *addr, int val)
84{
85 long res;
86
87 __asm volatile ("int $0x80"
88 : "=a" (res)
89 : "0" (SYS_futex), "b" (addr), "c" (gomp_futex_wait),
90 "d" (val), "S" (0)
91 : "memory");
92 if (__builtin_expect (res == -ENOSYS, 0))
93 {
94 gomp_futex_wait &= ~FUTEX_PRIVATE_FLAG;
95 gomp_futex_wake &= ~FUTEX_PRIVATE_FLAG;
96 __asm volatile ("int $0x80"
97 : "=a" (res)
98 : "0" (SYS_futex), "b" (addr), "c" (gomp_futex_wait),
99 "d" (val), "S" (0)
100 : "memory");
101 }
102}
103
104static inline void
105futex_wake (int *addr, int count)
106{
107 long res;
108
109 __asm volatile ("int $0x80"
110 : "=a" (res)
111 : "0" (SYS_futex), "b" (addr), "c" (gomp_futex_wake),
112 "d" (count)
113 : "memory");
114 if (__builtin_expect (res == -ENOSYS, 0))
115 {
116 gomp_futex_wait &= ~FUTEX_PRIVATE_FLAG;
117 gomp_futex_wake &= ~FUTEX_PRIVATE_FLAG;
118 __asm volatile ("int $0x80"
119 : "=a" (res)
120 : "0" (SYS_futex), "b" (addr), "c" (gomp_futex_wake),
121 "d" (count)
122 : "memory");
123 }
124}
125#endif /* __x86_64__ */
126
127static inline void
128cpu_relax (void)
129{
130 __builtin_ia32_pause ();
131}
132