mirror of
https://github.com/kdave/btrfs-progs
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7fba4bf4db
Add CPU_FLAG_NONE that's first in the list and represents a CPU without any acceleration features. Can be used for reference/fallback implementation. Signed-off-by: David Sterba <dsterba@suse.com>
116 lines
2.7 KiB
C
116 lines
2.7 KiB
C
/*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public
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* License v2 as published by the Free Software Foundation.
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*
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* This program 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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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public
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* License along with this program; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 021110-1307, USA.
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*/
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#include <stdio.h>
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#include <stdbool.h>
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#include "common/cpu-utils.h"
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unsigned long __cpu_flags = CPU_FLAG_NONE;
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unsigned long __cpu_flags_orig = CPU_FLAG_NONE;
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#ifdef __x86_64__
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/*
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* Do manual cpuid as cpuid.h is not available for all versions.
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*
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* Plain cpuid(level) is __cpuidex(level, 0), otherwise look for the leaf/subleaf
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* modes at https://en.wikipedia.org/wiki/CPUID or compilers' cpuid.h.
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*/
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#ifndef __cpuidex
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#define __cpuidex(leaf, subleaf, a, b, c, d) \
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__asm__ __volatile__ ("cpuid\n\t" \
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: "=a" (a), "=b" (b), "=c" (c), "=d" (d) \
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: "0" (leaf), "2" (subleaf))
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#endif
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#else
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#define __cpuidex(leaf, subleaf, a, b, c, d) \
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do { \
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a = 0; \
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b = 0; \
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c = 0; \
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d = 0; \
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} while(0)
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#endif
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#define FLAG(name) if (__cpu_flags & CPU_FLAG_ ## name) printf(" " #name)
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void cpu_print_flags(void) {
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printf("CPU flags: 0x%lx\n", __cpu_flags);
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printf("CPU features:");
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FLAG(SSE2);
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FLAG(SSSE3);
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FLAG(SSE41);
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FLAG(SSE42);
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FLAG(SHA);
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FLAG(AVX);
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FLAG(AVX2);
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putchar(10);
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}
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#undef FLAG
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#ifdef __x86_64__
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void cpu_detect_flags(void)
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{
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unsigned int a, b, c, d;
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__builtin_cpu_init();
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__cpu_flags = CPU_FLAG_NONE;
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if (__builtin_cpu_supports("sse2"))
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__cpu_flags |= CPU_FLAG_SSE2;
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if (__builtin_cpu_supports("ssse3"))
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__cpu_flags |= CPU_FLAG_SSSE3;
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if (__builtin_cpu_supports("sse4.1"))
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__cpu_flags |= CPU_FLAG_SSE41;
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if (__builtin_cpu_supports("sse4.2"))
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__cpu_flags |= CPU_FLAG_SSE42;
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if (__builtin_cpu_supports("avx"))
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__cpu_flags |= CPU_FLAG_AVX;
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if (__builtin_cpu_supports("avx2"))
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__cpu_flags |= CPU_FLAG_AVX2;
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/* Flags unsupported by builtins */
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__cpuidex(7, 0, a, b, c, d);
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if (b & (1UL << 29))
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__cpu_flags |= CPU_FLAG_SHA;
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__cpu_flags_orig = __cpu_flags;
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}
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void cpu_set_level(unsigned long topbit)
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{
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if (topbit)
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__cpu_flags &= (topbit << 1) - 1;
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else
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__cpu_flags = CPU_FLAG_NONE;
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}
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void cpu_reset_level(void)
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{
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__cpu_flags = __cpu_flags_orig;
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}
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#else
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void cpu_detect_flags() { }
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void cpu_set_level(unsigned long topbit) { }
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void cpu_reset_level(void) { }
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#endif
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