124 lines
3 KiB
C
124 lines
3 KiB
C
/* Copyright (C) 2005-2022 Free Software Foundation, Inc.
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Contributed by Richard Henderson <rth@redhat.com>.
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This file is part of the GNU Offloading and Multi Processing Library
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(libgomp).
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Libgomp is free software; you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3, or (at your option)
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any later version.
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Libgomp is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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more details.
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Under Section 7 of GPL version 3, you are granted additional
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permissions described in the GCC Runtime Library Exception, version
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3.1, as published by the Free Software Foundation.
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You should have received a copy of the GNU General Public License and
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a copy of the GCC Runtime Library Exception along with this program;
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see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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<http://www.gnu.org/licenses/>. */
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/* Provide target-specific access to the futex system call. */
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#ifdef __x86_64__
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# ifndef SYS_futex
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# define SYS_futex 202
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# endif
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static inline long
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__futex_wait (int *addr, int futex_op, int val)
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{
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long res;
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register void *timeout __asm ("r10") = NULL;
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__asm volatile ("syscall"
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: "=a" (res)
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: "0" (SYS_futex), "D" (addr), "S" (futex_op),
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"d" (val), "r" (timeout)
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: "r11", "rcx", "memory");
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return res;
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}
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static inline long
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__futex_wake (int *addr, int futex_op, int count)
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{
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long res;
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__asm volatile ("syscall"
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: "=a" (res)
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: "0" (SYS_futex), "D" (addr), "S" (futex_op),
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"d" (count)
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: "r11", "rcx", "memory");
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return res;
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}
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#else
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# ifndef SYS_futex
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# define SYS_futex 240
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# endif
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static inline long
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__futex_wait (int *addr, int futex_op, int val)
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{
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long res;
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void *timeout = NULL;
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__asm volatile ("int $0x80"
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: "=a" (res)
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: "0" (SYS_futex), "b" (addr), "c" (futex_op),
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"d" (val), "S" (timeout)
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: "memory");
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return res;
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}
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static inline long
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__futex_wake (int *addr, int futex_op, int count)
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{
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long res;
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__asm volatile ("int $0x80"
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: "=a" (res)
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: "0" (SYS_futex), "b" (addr), "c" (futex_op),
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"d" (count)
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: "memory");
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return res;
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}
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#endif /* __x86_64__ */
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static inline void
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futex_wait (int *addr, int val)
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{
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long err = __futex_wait (addr, gomp_futex_wait, val);
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if (__builtin_expect (err == -ENOSYS, 0))
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{
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gomp_futex_wait &= ~FUTEX_PRIVATE_FLAG;
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gomp_futex_wake &= ~FUTEX_PRIVATE_FLAG;
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__futex_wait (addr, gomp_futex_wait, val);
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}
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}
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static inline void
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futex_wake (int *addr, int count)
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{
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long err = __futex_wake (addr, gomp_futex_wake, count);
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if (__builtin_expect (err == -ENOSYS, 0))
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{
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gomp_futex_wait &= ~FUTEX_PRIVATE_FLAG;
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gomp_futex_wake &= ~FUTEX_PRIVATE_FLAG;
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__futex_wake (addr, gomp_futex_wake, count);
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}
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}
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static inline void
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cpu_relax (void)
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{
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__builtin_ia32_pause ();
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}
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