E.3 X86-specific Facilities

Facilities specific to X86 that are not specific to a particular operating system are declared in sys/platform/x86.h.

Function: const struct cpuid_feature * __x86_get_cpuid_feature_leaf (unsigned int leaf) ¶

Preliminary: | MT-Safe | AS-Safe | AC-Safe | See POSIX Safety Concepts.

Return a pointer to x86 CPU feature structure used by query macros for x86 CPU feature leaf.

Macro: int CPU_FEATURE_PRESENT (name) ¶

This macro returns a nonzero value (true) if the processor has the feature name.

Macro: int CPU_FEATURE_ACTIVE (name) ¶

This macro returns a nonzero value (true) if the processor has the feature name and 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.

The supported processor features are:

• ACPI – Thermal Monitor and Software Controlled Clock Facilities.
• ADX – ADX instruction extensions.
• APIC – APIC On-Chip.
• AES – The AES instruction extensions.
• AESKLE – AES Key Locker instructions are enabled by OS.
• AMD_IBPB – Indirect branch predictor barrier (IBPB) for AMD cpus.
• AMD_IBRS – Indirect branch restricted speculation (IBPB) for AMD cpus.
• AMD_SSBD – Speculative Store Bypass Disable (SSBD) for AMD cpus.
• AMD_STIBP – Single thread indirect branch predictors (STIBP) for AMD cpus.
• AMD_VIRT_SSBD – Speculative Store Bypass Disable (SSBD) for AMD cpus (older systems).
• AMX_BF16 – Tile computational operations on bfloat16 numbers.
• AMX_INT8 – Tile computational operations on 8-bit numbers.
• AMX_TILE – Tile architecture.
• ARCH_CAPABILITIES – IA32_ARCH_CAPABILITIES MSR.
• AVX – The AVX instruction extensions.
• AVX2 – The AVX2 instruction extensions.
• AVX_VNNI – The AVX-VNNI instruction extensions.
• AVX512_4FMAPS – The AVX512_4FMAPS instruction extensions.
• AVX512_4VNNIW – The AVX512_4VNNIW instruction extensions.
• AVX512_BF16 – The AVX512_BF16 instruction extensions.
• AVX512_BITALG – The AVX512_BITALG instruction extensions.
• AVX512_FP16 – The AVX512_FP16 instruction extensions.
• AVX512_IFMA – The AVX512_IFMA instruction extensions.
• AVX512_VBMI – The AVX512_VBMI instruction extensions.
• AVX512_VBMI2 – The AVX512_VBMI2 instruction extensions.
• AVX512_VNNI – The AVX512_VNNI instruction extensions.
• AVX512_VP2INTERSECT – The AVX512_VP2INTERSECT instruction extensions.
• AVX512_VPOPCNTDQ – The AVX512_VPOPCNTDQ instruction extensions.
• AVX512BW – The AVX512BW instruction extensions.
• AVX512CD – The AVX512CD instruction extensions.
• AVX512ER – The AVX512ER instruction extensions.
• AVX512DQ – The AVX512DQ instruction extensions.
• AVX512F – The AVX512F instruction extensions.
• AVX512PF – The AVX512PF instruction extensions.
• AVX512VL – The AVX512VL instruction extensions.
• BMI1 – BMI1 instructions.
• BMI2 – BMI2 instructions.
• CLDEMOTE – CLDEMOTE instruction.
• CLFLUSHOPT – CLFLUSHOPT instruction.
• CLFSH – CLFLUSH instruction.
• CLWB – CLWB instruction.
• CMOV – Conditional Move instructions.
• CMPXCHG16B – CMPXCHG16B instruction.
• CNXT_ID – L1 Context ID.
• CORE_CAPABILITIES – IA32_CORE_CAPABILITIES MSR.
• CX8 – CMPXCHG8B instruction.
• DCA – Data prefetch from a memory mapped device.
• DE – Debugging Extensions.
• DEPR_FPU_CS_DS – Deprecates FPU CS and FPU DS values.
• DS – Debug Store.
• DS_CPL – CPL Qualified Debug Store.
• DTES64 – 64-bit DS Area.
• EIST – Enhanced Intel SpeedStep technology.
• ENQCMD – Enqueue Stores instructions.
• ERMS – Enhanced REP MOVSB/STOSB.
• F16C – 16-bit floating-point conversion instructions.
• FMA – FMA extensions using YMM state.
• FMA4 – FMA4 instruction extensions.
• FPU – X87 Floating Point Unit On-Chip.
• FSGSBASE – RDFSBASE/RDGSBASE/WRFSBASE/WRGSBASE instructions.
• FSRCS – Fast Short REP CMP and SCA.
• FSRM – Fast Short REP MOV.
• FSRS – Fast Short REP STO.
• FXSR – FXSAVE and FXRSTOR instructions.
• FZLRM – Fast Zero-Length REP MOV.
• GFNI – GFNI instruction extensions.
• HLE – HLE instruction extensions.
• HTT – Max APIC IDs reserved field is Valid.
• HRESET – History reset.
• HYBRID – Hybrid processor.
• IBRS_IBPB – Indirect branch restricted speculation (IBRS) and the indirect branch predictor barrier (IBPB).
• IBT – Intel Indirect Branch Tracking instruction extensions.
• INVARIANT_TSC – Invariant TSC.
• INVPCID – INVPCID instruction.
• KL – AES Key Locker instructions.
• LAM – Linear Address Masking.
• L1D_FLUSH – IA32_FLUSH_CMD MSR.
• LAHF64_SAHF64 – LAHF/SAHF available in 64-bit mode.
• LM – Long mode.
• LWP – Lightweight profiling.
• LZCNT – LZCNT instruction.
• MCA – Machine Check Architecture.
• MCE – Machine Check Exception.
• MD_CLEAR – MD_CLEAR.
• MMX – Intel MMX Technology.
• MONITOR – MONITOR/MWAIT instructions.
• MOVBE – MOVBE instruction.
• MOVDIRI – MOVDIRI instruction.
• MOVDIR64B – MOVDIR64B instruction.
• MPX – Intel Memory Protection Extensions.
• MSR – Model Specific Registers RDMSR and WRMSR instructions.
• MTRR – Memory Type Range Registers.
• NX – No-execute page protection.
• OSPKE – OS has set CR4.PKE to enable protection keys.
• OSXSAVE – The OS has set CR4.OSXSAVE[bit 18] to enable XSETBV/XGETBV instructions to access XCR0 and to support processor extended state management using XSAVE/XRSTOR.
• PAE – Physical Address Extension.
• PAGE1GB – 1-GByte page.
• PAT – Page Attribute Table.
• PBE – Pending Break Enable.
• PCID – Process-context identifiers.
• PCLMULQDQ – PCLMULQDQ instruction.
• PCONFIG – PCONFIG instruction.
• PDCM – Perfmon and Debug Capability.
• PGE – Page Global Bit.
• PKS – Protection keys for supervisor-mode pages.
• PKU – Protection keys for user-mode pages.
• POPCNT – POPCNT instruction.
• PREFETCHW – PREFETCHW instruction.
• PREFETCHWT1 – PREFETCHWT1 instruction.
• PSE – Page Size Extension.
• PSE_36 – 36-Bit Page Size Extension.
• PSN – Processor Serial Number.
• PTWRITE – PTWRITE instruction.
• RDPID – RDPID instruction.
• RDRAND – RDRAND instruction.
• RDSEED – RDSEED instruction.
• RDT_A – Intel Resource Director Technology (Intel RDT) Allocation capability.
• RDT_M – Intel Resource Director Technology (Intel RDT) Monitoring capability.
• RDTSCP – RDTSCP instruction.
• RTM – RTM instruction extensions.
• RTM_ALWAYS_ABORT – Transactions always abort, making RTM unusable.
• SDBG – IA32_DEBUG_INTERFACE MSR for silicon debug.
• SEP – SYSENTER and SYSEXIT instructions.
• SERIALIZE – SERIALIZE instruction.
• SGX – Intel Software Guard Extensions.
• SGX_LC – SGX Launch Configuration.
• SHA – SHA instruction extensions.
• SHSTK – Intel Shadow Stack instruction extensions.
• SMAP – Supervisor-Mode Access Prevention.
• SMEP – Supervisor-Mode Execution Prevention.
• SMX – Safer Mode Extensions.
• SS – Self Snoop.
• SSBD – Speculative Store Bypass Disable (SSBD).
• SSE – Streaming SIMD Extensions.
• SSE2 – Streaming SIMD Extensions 2.
• SSE3 – Streaming SIMD Extensions 3.
• SSE4_1 – Streaming SIMD Extensions 4.1.
• SSE4_2 – Streaming SIMD Extensions 4.2.
• SSE4A – SSE4A instruction extensions.
• SSSE3 – Supplemental Streaming SIMD Extensions 3.
• STIBP – Single thread indirect branch predictors (STIBP).
• SVM – Secure Virtual Machine.
• SYSCALL_SYSRET – SYSCALL/SYSRET instructions.
• TBM – Trailing bit manipulation instructions.
• TM – Thermal Monitor.
• TM2 – Thermal Monitor 2.
• TRACE – Intel Processor Trace.
• TSC – Time Stamp Counter. RDTSC instruction.
• TSC_ADJUST – IA32_TSC_ADJUST MSR.
• TSC_DEADLINE – Local APIC timer supports one-shot operation using a TSC deadline value.
• TSXLDTRK – TSXLDTRK instructions.
• UINTR – User interrupts.
• UMIP – User-mode instruction prevention.
• VAES – VAES instruction extensions.
• VME – Virtual 8086 Mode Enhancements.
• VMX – Virtual Machine Extensions.
• VPCLMULQDQ – VPCLMULQDQ instruction.
• WAITPKG – WAITPKG instruction extensions.
• WBNOINVD – WBINVD/WBNOINVD instructions.
• WIDE_KL – AES wide Key Locker instructions.
• X2APIC – x2APIC.
• XFD – Extended Feature Disable (XFD).
• XGETBV_ECX_1 – XGETBV with ECX = 1.
• XOP – XOP instruction extensions.
• XSAVE – The XSAVE/XRSTOR processor extended states feature, the XSETBV/XGETBV instructions, and XCR0.
• XSAVEC – XSAVEC instruction.
• XSAVEOPT – XSAVEOPT instruction.
• XSAVES – XSAVES/XRSTORS instructions.
• XTPRUPDCTRL – xTPR Update Control.

You could query if a processor supports AVX with:

#include <sys/platform/x86.h>

int
avx_present (void)
{
  return CPU_FEATURE_PRESENT (AVX);
}

and if AVX is active and may be used with:

#include <sys/platform/x86.h>

int
avx_active (void)
{
  return CPU_FEATURE_ACTIVE (AVX);
}