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/*
* SPDX-License-Identifier: GPL-2.0-or-later
* Host specific cpu indentification for x86.
*/
#include "qemu/osdep.h"
#include "host/cpuinfo.h"
#ifdef CONFIG_CPUID_H
# include "qemu/cpuid.h"
#endif
unsigned cpuinfo;
/* Called both as constructor and (possibly) via other constructors. */
unsigned __attribute__((constructor)) cpuinfo_init(void)
{
unsigned info = cpuinfo;
if (info) {
return info;
}
#ifdef CONFIG_CPUID_H
unsigned max, a, b, c, d, b7 = 0, c7 = 0;
max = __get_cpuid_max(0, 0);
if (max >= 7) {
__cpuid_count(7, 0, a, b7, c7, d);
info |= (b7 & bit_BMI ? CPUINFO_BMI1 : 0);
info |= (b7 & bit_BMI2 ? CPUINFO_BMI2 : 0);
}
if (max >= 1) {
__cpuid(1, a, b, c, d);
info |= (d & bit_CMOV ? CPUINFO_CMOV : 0);
info |= (d & bit_SSE2 ? CPUINFO_SSE2 : 0);
info |= (c & bit_SSE4_1 ? CPUINFO_SSE4 : 0);
info |= (c & bit_MOVBE ? CPUINFO_MOVBE : 0);
info |= (c & bit_POPCNT ? CPUINFO_POPCNT : 0);
/* For AVX features, we must check available and usable. */
if ((c & bit_AVX) && (c & bit_OSXSAVE)) {
unsigned bv = xgetbv_low(0);
if ((bv & 6) == 6) {
info |= CPUINFO_AVX1;
info |= (b7 & bit_AVX2 ? CPUINFO_AVX2 : 0);
if ((bv & 0xe0) == 0xe0) {
info |= (b7 & bit_AVX512F ? CPUINFO_AVX512F : 0);
info |= (b7 & bit_AVX512VL ? CPUINFO_AVX512VL : 0);
info |= (b7 & bit_AVX512BW ? CPUINFO_AVX512BW : 0);
info |= (b7 & bit_AVX512DQ ? CPUINFO_AVX512DQ : 0);
info |= (c7 & bit_AVX512VBMI2 ? CPUINFO_AVX512VBMI2 : 0);
}
/*
* The Intel SDM has added:
* Processors that enumerate support for Intel® AVX
* (by setting the feature flag CPUID.01H:ECX.AVX[bit 28])
* guarantee that the 16-byte memory operations performed
* by the following instructions will always be carried
* out atomically:
* - MOVAPD, MOVAPS, and MOVDQA.
* - VMOVAPD, VMOVAPS, and VMOVDQA when encoded with VEX.128.
* - VMOVAPD, VMOVAPS, VMOVDQA32, and VMOVDQA64 when encoded
* with EVEX.128 and k0 (masking disabled).
* Note that these instructions require the linear addresses
* of their memory operands to be 16-byte aligned.
*
* AMD has provided an even stronger guarantee that processors
* with AVX provide 16-byte atomicity for all cachable,
* naturally aligned single loads and stores, e.g. MOVDQU.
*
* See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104688
*/
__cpuid(0, a, b, c, d);
if (c == signature_INTEL_ecx || c == signature_AMD_ecx) {
info |= CPUINFO_ATOMIC_VMOVDQA;
}
}
}
}
max = __get_cpuid_max(0x8000000, 0);
if (max >= 1) {
__cpuid(0x80000001, a, b, c, d);
info |= (c & bit_LZCNT ? CPUINFO_LZCNT : 0);
}
#endif
info |= CPUINFO_ALWAYS;
cpuinfo = info;
return info;
}
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