49 lines
1.6 KiB
C
49 lines
1.6 KiB
C
/* Out-of-line LSE atomics for AArch64 architecture, Init.
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Copyright (C) 2019-2022 Free Software Foundation, Inc.
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Contributed by Linaro Ltd.
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free
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Software Foundation; either version 3, or (at your option) any later
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version.
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GCC 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
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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for 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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#include "auto-target.h"
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/* Define the symbol gating the LSE implementations. */
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_Bool __aarch64_have_lse_atomics
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__attribute__((visibility("hidden"), nocommon));
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/* Gate availability of __getauxval on glibc. All AArch64-supporting glibc
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versions support it. */
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#ifdef __gnu_linux__
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# define AT_HWCAP 16
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# define HWCAP_ATOMICS (1 << 8)
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unsigned long int __getauxval (unsigned long int);
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static void __attribute__((constructor))
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init_have_lse_atomics (void)
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{
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unsigned long hwcap = __getauxval (AT_HWCAP);
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__aarch64_have_lse_atomics = (hwcap & HWCAP_ATOMICS) != 0;
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}
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#endif /* __gnu_linux__ */
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