| /* Copyright (C) 2010-2022 Free Software Foundation, Inc. |
| Contributed by ARM Ltd. |
| |
| This file is part of the GNU Offloading and Multi Processing Library |
| (libgomp). |
| |
| Libgomp 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, or (at your option) |
| any later version. |
| |
| Libgomp 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 target-specific access to the futex system call. */ |
| |
| /* The include file hierachy above us (wait.h) has pushed visibility |
| hidden, this will be applied to prototypes with headers we include |
| with the effect that we cannot link against an external function |
| (syscall). The solution here is to push default visibility, include |
| our required headers then reinstante the original visibility. */ |
| |
| #pragma GCC visibility push(default) |
| |
| #define _GNU_SOURCE |
| #include <unistd.h> |
| #include <sys/syscall.h> |
| |
| #pragma GCC visibility pop |
| |
| static inline void |
| futex_wait (int *addr, int val) |
| { |
| int err = syscall (SYS_futex, addr, gomp_futex_wait, val, NULL); |
| if (__builtin_expect (err < 0 && errno == ENOSYS, 0)) |
| { |
| gomp_futex_wait &= ~FUTEX_PRIVATE_FLAG; |
| gomp_futex_wake &= ~FUTEX_PRIVATE_FLAG; |
| syscall (SYS_futex, addr, gomp_futex_wait, val, NULL); |
| } |
| } |
| |
| static inline void |
| futex_wake (int *addr, int count) |
| { |
| int err = syscall (SYS_futex, addr, gomp_futex_wake, count); |
| if (__builtin_expect (err < 0 && errno == ENOSYS, 0)) |
| { |
| gomp_futex_wait &= ~FUTEX_PRIVATE_FLAG; |
| gomp_futex_wake &= ~FUTEX_PRIVATE_FLAG; |
| syscall (SYS_futex, addr, gomp_futex_wake, count); |
| } |
| } |
| |
| static inline void |
| cpu_relax (void) |
| { |
| __asm volatile ("" : : : "memory"); |
| } |