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// SPDX-License-Identifier: BSD-3-Clause
/* Copyright 2015-2020, Intel Corporation */
/*
* cpu.c -- CPU features detection
*/
/*
* Reference:
* http://www.intel.com/content/www/us/en/processors/
* architectures-software-developer-manuals.html
*
* https://support.amd.com/TechDocs/24594.pdf
*/
#include <string.h>
#include "out.h"
#include "cpu.h"
#define EAX_IDX 0
#define EBX_IDX 1
#define ECX_IDX 2
#define EDX_IDX 3
#if defined(__x86_64__) || defined(__amd64__)
#include <cpuid.h>
static inline void
cpuid(unsigned func, unsigned subfunc, unsigned cpuinfo[4])
{
__cpuid_count(func, subfunc, cpuinfo[EAX_IDX], cpuinfo[EBX_IDX],
cpuinfo[ECX_IDX], cpuinfo[EDX_IDX]);
}
#elif defined(_M_X64) || defined(_M_AMD64)
#include <intrin.h>
static inline void
cpuid(unsigned func, unsigned subfunc, unsigned cpuinfo[4])
{
__cpuidex(cpuinfo, func, subfunc);
}
#else
#error unsupported compiler
#endif
#ifndef bit_CLFLUSH
#define bit_CLFLUSH (1 << 19)
#endif
#ifndef bit_CLFLUSHOPT
#define bit_CLFLUSHOPT (1 << 23)
#endif
#ifndef bit_CLWB
#define bit_CLWB (1 << 24)
#endif
#ifndef bit_AVX
#define bit_AVX (1 << 28)
#endif
#ifndef bit_AVX512F
#define bit_AVX512F (1 << 16)
#endif
/*
* is_cpu_feature_present -- (internal) checks if CPU feature is supported
*/
static int
is_cpu_feature_present(unsigned func, unsigned reg, unsigned bit)
{
unsigned cpuinfo[4] = { 0 };
/* check CPUID level first */
cpuid(0x0, 0x0, cpuinfo);
if (cpuinfo[EAX_IDX] < func)
return 0;
cpuid(func, 0x0, cpuinfo);
return (cpuinfo[reg] & bit) != 0;
}
/*
* is_cpu_genuine_intel -- checks for genuine Intel CPU
*/
int
is_cpu_genuine_intel(void)
{
unsigned cpuinfo[4] = { 0 };
union {
char name[0x20];
unsigned cpuinfo[3];
} vendor;
memset(&vendor, 0, sizeof(vendor));
cpuid(0x0, 0x0, cpuinfo);
vendor.cpuinfo[0] = cpuinfo[EBX_IDX];
vendor.cpuinfo[1] = cpuinfo[EDX_IDX];
vendor.cpuinfo[2] = cpuinfo[ECX_IDX];
LOG(4, "CPU vendor: %s", vendor.name);
return (strncmp(vendor.name, "GenuineIntel",
sizeof(vendor.name))) == 0;
}
/*
* is_cpu_clflush_present -- checks if CLFLUSH instruction is supported
*/
int
is_cpu_clflush_present(void)
{
int ret = is_cpu_feature_present(0x1, EDX_IDX, bit_CLFLUSH);
LOG(4, "CLFLUSH %ssupported", ret == 0 ? "not " : "");
return ret;
}
/*
* is_cpu_clflushopt_present -- checks if CLFLUSHOPT instruction is supported
*/
int
is_cpu_clflushopt_present(void)
{
int ret = is_cpu_feature_present(0x7, EBX_IDX, bit_CLFLUSHOPT);
LOG(4, "CLFLUSHOPT %ssupported", ret == 0 ? "not " : "");
return ret;
}
/*
* is_cpu_clwb_present -- checks if CLWB instruction is supported
*/
int
is_cpu_clwb_present(void)
{
int ret = is_cpu_feature_present(0x7, EBX_IDX, bit_CLWB);
LOG(4, "CLWB %ssupported", ret == 0 ? "not " : "");
return ret;
}
/*
* is_cpu_avx_present -- checks if AVX instructions are supported
*/
int
is_cpu_avx_present(void)
{
int ret = is_cpu_feature_present(0x1, ECX_IDX, bit_AVX);
LOG(4, "AVX %ssupported", ret == 0 ? "not " : "");
return ret;
}
/*
* is_cpu_avx512f_present -- checks if AVX-512f instructions are supported
*/
int
is_cpu_avx512f_present(void)
{
int ret = is_cpu_feature_present(0x7, EBX_IDX, bit_AVX512F);
LOG(4, "AVX512f %ssupported", ret == 0 ? "not " : "");
return ret;
}
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