| /* Copyright (C) 2008-2022 Free Software Foundation, Inc. |
| Contributed by Richard Henderson <rth@redhat.com>. |
| |
| This file is part of the GNU Transactional Memory Library (libitm). |
| |
| Libitm is free software; you can redistribute it and/or modify it |
| under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 3 of the License, or |
| (at your option) any later version. |
| |
| Libitm is distributed in the hope that it will be useful, but WITHOUT ANY |
| WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS |
| FOR A PARTICULAR PURPOSE. See the GNU General Public License for |
| more details. |
| |
| Under Section 7 of GPL version 3, you are granted additional |
| permissions described in the GCC Runtime Library Exception, version |
| 3.1, as published by the Free Software Foundation. |
| |
| You should have received a copy of the GNU General Public License and |
| a copy of the GCC Runtime Library Exception along with this program; |
| see the files COPYING3 and COPYING.RUNTIME respectively. If not, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| /* Provide access to the futex system call. */ |
| |
| #include "libitm_i.h" |
| #include "futex.h" |
| #include <futex_bits.h> |
| #include <errno.h> |
| |
| namespace GTM HIDDEN { |
| |
| #define FUTEX_WAIT 0 |
| #define FUTEX_WAKE 1 |
| #define FUTEX_PRIVATE_FLAG 128 |
| |
| |
| static int gtm_futex_wait = FUTEX_WAIT | FUTEX_PRIVATE_FLAG; |
| static int gtm_futex_wake = FUTEX_WAKE | FUTEX_PRIVATE_FLAG; |
| |
| |
| void |
| futex_wait (std::atomic<int> *addr, int val) |
| { |
| long res; |
| |
| res = sys_futex0 (addr, gtm_futex_wait, val); |
| if (__builtin_expect (res == -ENOSYS, 0)) |
| { |
| gtm_futex_wait = FUTEX_WAIT; |
| gtm_futex_wake = FUTEX_WAKE; |
| res = sys_futex0 (addr, FUTEX_WAIT, val); |
| } |
| if (__builtin_expect (res < 0, 0)) |
| { |
| if (res == -EWOULDBLOCK || res == -ETIMEDOUT) |
| ; |
| else if (res == -EFAULT) |
| GTM_fatal ("futex failed (EFAULT %p)", addr); |
| else |
| GTM_fatal ("futex failed (%s)", strerror(-res)); |
| } |
| } |
| |
| |
| long |
| futex_wake (std::atomic<int> *addr, int count) |
| { |
| long res = sys_futex0 (addr, gtm_futex_wake, count); |
| if (__builtin_expect (res == -ENOSYS, 0)) |
| { |
| gtm_futex_wait = FUTEX_WAIT; |
| gtm_futex_wake = FUTEX_WAKE; |
| res = sys_futex0 (addr, FUTEX_WAKE, count); |
| } |
| if (__builtin_expect (res < 0, 0)) |
| GTM_fatal ("futex failed (%s)", strerror(-res)); |
| else |
| return res; |
| } |
| |
| } // namespace GTM |