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- /* Out-of-line LSE atomics for AArch64 architecture, Init.
- Copyright (C) 2019-2022 Free Software Foundation, Inc.
- Contributed by Linaro Ltd.
- This file is part of GCC.
- GCC 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.
- GCC 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/>. */
- #include "auto-target.h"
- /* Define the symbol gating the LSE implementations. */
- _Bool __aarch64_have_lse_atomics
- __attribute__((visibility("hidden"), nocommon));
- /* Gate availability of __getauxval on glibc. All AArch64-supporting glibc
- versions support it. */
- #ifdef __gnu_linux__
- # define AT_HWCAP 16
- # define HWCAP_ATOMICS (1 << 8)
- unsigned long int __getauxval (unsigned long int);
- static void __attribute__((constructor))
- init_have_lse_atomics (void)
- {
- unsigned long hwcap = __getauxval (AT_HWCAP);
- __aarch64_have_lse_atomics = (hwcap & HWCAP_ATOMICS) != 0;
- }
- #endif /* __gnu_linux__ */
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