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fbd26352 | 1 | /* Copyright (C) 2008-2019 Free Software Foundation, Inc. |
4c0315d0 | 2 | Contributed by Richard Henderson <rth@redhat.com>. |
3 | ||
4 | This file is part of the GNU Transactional Memory Library (libitm). | |
5 | ||
6 | Libitm is free software; you can redistribute it and/or modify it | |
7 | under the terms of the GNU General Public License as published by | |
8 | the Free Software Foundation; either version 3 of the License, or | |
9 | (at your option) any later version. | |
10 | ||
11 | Libitm is distributed in the hope that it will be useful, but WITHOUT ANY | |
12 | WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS | |
13 | FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
14 | more details. | |
15 | ||
16 | Under Section 7 of GPL version 3, you are granted additional | |
17 | permissions described in the GCC Runtime Library Exception, version | |
18 | 3.1, as published by the Free Software Foundation. | |
19 | ||
20 | You should have received a copy of the GNU General Public License and | |
21 | a copy of the GCC Runtime Library Exception along with this program; | |
22 | see the files COPYING3 and COPYING.RUNTIME respectively. If not, see | |
23 | <http://www.gnu.org/licenses/>. */ | |
24 | ||
25 | /* Provide access to the futex system call. */ | |
26 | ||
27 | #include "libitm_i.h" | |
28 | #include "futex.h" | |
dd120a97 | 29 | #include <futex_bits.h> |
4c0315d0 | 30 | #include <errno.h> |
31 | ||
32 | namespace GTM HIDDEN { | |
33 | ||
34 | #define FUTEX_WAIT 0 | |
35 | #define FUTEX_WAKE 1 | |
da3b7968 | 36 | #define FUTEX_PRIVATE_FLAG 128 |
4c0315d0 | 37 | |
38 | ||
da3b7968 | 39 | static int gtm_futex_wait = FUTEX_WAIT | FUTEX_PRIVATE_FLAG; |
40 | static int gtm_futex_wake = FUTEX_WAKE | FUTEX_PRIVATE_FLAG; | |
4c0315d0 | 41 | |
42 | ||
43 | void | |
813b3075 | 44 | futex_wait (std::atomic<int> *addr, int val) |
4c0315d0 | 45 | { |
46 | long res; | |
47 | ||
48 | res = sys_futex0 (addr, gtm_futex_wait, val); | |
49 | if (__builtin_expect (res == -ENOSYS, 0)) | |
50 | { | |
51 | gtm_futex_wait = FUTEX_WAIT; | |
52 | gtm_futex_wake = FUTEX_WAKE; | |
53 | res = sys_futex0 (addr, FUTEX_WAIT, val); | |
54 | } | |
55 | if (__builtin_expect (res < 0, 0)) | |
56 | { | |
57 | if (res == -EWOULDBLOCK || res == -ETIMEDOUT) | |
58 | ; | |
59 | else if (res == -EFAULT) | |
60 | GTM_fatal ("futex failed (EFAULT %p)", addr); | |
61 | else | |
62 | GTM_fatal ("futex failed (%s)", strerror(-res)); | |
63 | } | |
64 | } | |
65 | ||
66 | ||
67 | long | |
813b3075 | 68 | futex_wake (std::atomic<int> *addr, int count) |
4c0315d0 | 69 | { |
70 | long res = sys_futex0 (addr, gtm_futex_wake, count); | |
71 | if (__builtin_expect (res == -ENOSYS, 0)) | |
72 | { | |
73 | gtm_futex_wait = FUTEX_WAIT; | |
74 | gtm_futex_wake = FUTEX_WAKE; | |
75 | res = sys_futex0 (addr, FUTEX_WAKE, count); | |
76 | } | |
77 | if (__builtin_expect (res < 0, 0)) | |
78 | GTM_fatal ("futex failed (%s)", strerror(-res)); | |
79 | else | |
80 | return res; | |
81 | } | |
82 | ||
83 | } // namespace GTM |