7c124e3714
1. Install <bits/platform/x86.h> for <sys/platform/x86.h> which includes <bits/platform/x86.h>. 2. Rename HAS_CPU_FEATURE to CPU_FEATURE_PRESENT which checks if the processor has the feature. 3. Rename CPU_FEATURE_USABLE to CPU_FEATURE_ACTIVE which checks if the feature is active. There may be other preconditions, like sufficient stack space or further setup for AMX, which must be satisfied before the feature can be used. This fixes BZ #27958. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
107 lines
1.9 KiB
C
107 lines
1.9 KiB
C
/* IFUNC resolver with CPU_FEATURE_ACTIVE.
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Copyright (C) 2021 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <sys/platform/x86.h>
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enum isa
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{
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none,
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sse2,
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sse4_2,
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avx,
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avx2,
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avx512f
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};
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enum isa
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__attribute__ ((__optimize__ ("-fno-stack-protector")))
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get_isa (void)
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{
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if (CPU_FEATURE_ACTIVE (AVX512F))
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return avx512f;
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if (CPU_FEATURE_ACTIVE (AVX2))
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return avx2;
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if (CPU_FEATURE_ACTIVE (AVX))
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return avx;
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if (CPU_FEATURE_ACTIVE (SSE4_2))
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return sse4_2;
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if (CPU_FEATURE_ACTIVE (SSE2))
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return sse2;
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return none;
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}
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static int
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isa_sse2 (void)
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{
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return sse2;
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}
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static int
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isa_sse4_2 (void)
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{
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return sse4_2;
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}
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static int
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isa_avx (void)
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{
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return avx;
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}
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static int
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isa_avx2 (void)
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{
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return avx2;
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}
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static int
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isa_avx512f (void)
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{
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return avx512f;
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}
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static int
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isa_none (void)
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{
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return none;
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}
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int foo (void) __attribute__ ((ifunc ("foo_ifunc")));
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void *
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__attribute__ ((__optimize__ ("-fno-stack-protector")))
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foo_ifunc (void)
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{
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switch (get_isa ())
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{
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case avx512f:
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return isa_avx512f;
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case avx2:
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return isa_avx2;
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case avx:
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return isa_avx;
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case sse4_2:
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return isa_sse4_2;
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case sse2:
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return isa_sse2;
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default:
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break;
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}
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return isa_none;
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}
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