libcpuid(3)

NAME
libcpuid - LibCPUID

 - LibCPUID provides CPU identification.

SYNOPSIS

  Data Structures

struct cpu_raw_data_t
Contains just the raw CPUID data.
struct cpu_raw_data_array_t
Contains an array of raw CPUID data.
struct cpu_sgx_t
This contains information about SGX features of the processor Example usage:
struct x86_id_t
Contains x86 specific info.
struct arm_id_t
Contains ARM specific info.
struct cpu_id_t
This contains the recognized CPU features/info.
struct system_id_t
This contains the recognized features/info for all CPUs on the system.
struct cpu_mark_t
Internal structure, used in cpu_tsc_mark, cpu_tsc_unmark and cpu_clock_by_mark.
struct cpu_epc_t
The return value of cpuid_get_epc().
struct cpu_list_t
a structure that holds a list of processor names

  Macros

#define LIBCPUID_DEPRECATED(message)
#define NUM_CPU_VENDORS NUM_CPU_VENDORS
#define NUM_CPU_ARCHITECTURES NUM_CPU_ARCHITECTURES
#define NUM_FEATURE_LEVELS NUM_FEATURE_LEVELS
#define NUM_CPU_PURPOSES NUM_CPU_PURPOSES
#define NUM_HYPERVISOR_VENDORS NUM_HYPERVISOR_VENDORS
#define CPU_INVALID_VALUE 0x3fffffff

  Typedefs

typedef void(* libcpuid_warn_fn_t) (const char *msg)

  Enumerations

enum cpu_vendor_t { VENDOR_INTEL = 0, VENDOR_AMD, VENDOR_CYRIX, VENDOR_NEXGEN, VENDOR_TRANSMETA, VENDOR_UMC, VENDOR_CENTAUR, VENDOR_RISE, VENDOR_SIS, VENDOR_NSC, VENDOR_HYGON, VENDOR_ARM, VENDOR_BROADCOM, VENDOR_CAVIUM, VENDOR_DEC, VENDOR_FUJITSU, VENDOR_HISILICON, VENDOR_INFINEON, VENDOR_FREESCALE, VENDOR_NVIDIA, VENDOR_APM, VENDOR_QUALCOMM, VENDOR_SAMSUNG, VENDOR_MARVELL, VENDOR_APPLE, VENDOR_FARADAY, VENDOR_MICROSOFT, VENDOR_PHYTIUM, VENDOR_AMPERE, NUM_CPU_VENDORS, VENDOR_UNKNOWN = -1 }
CPU vendor, as guessed from the Vendor String.
enum cpu_architecture_t { ARCHITECTURE_X86 = 0, ARCHITECTURE_ARM, NUM_CPU_ARCHITECTURES, ARCHITECTURE_UNKNOWN = -1 }
CPU architecture.
enum cpu_feature_level_t { FEATURE_LEVEL_I386, FEATURE_LEVEL_I486, FEATURE_LEVEL_I586, FEATURE_LEVEL_I686, FEATURE_LEVEL_X86_64_V1, FEATURE_LEVEL_X86_64_V2, FEATURE_LEVEL_X86_64_V3, FEATURE_LEVEL_X86_64_V4, FEATURE_LEVEL_ARM_V1 = 100, FEATURE_LEVEL_ARM_V2, FEATURE_LEVEL_ARM_V3, FEATURE_LEVEL_ARM_V4, FEATURE_LEVEL_ARM_V4T, FEATURE_LEVEL_ARM_V5, FEATURE_LEVEL_ARM_V5T, FEATURE_LEVEL_ARM_V5TE, FEATURE_LEVEL_ARM_V5TEJ, FEATURE_LEVEL_ARM_V6, FEATURE_LEVEL_ARM_V6_M, FEATURE_LEVEL_ARM_V7_A, FEATURE_LEVEL_ARM_V7_M, FEATURE_LEVEL_ARM_V7_R, FEATURE_LEVEL_ARM_V7E_M, FEATURE_LEVEL_ARM_V8_0_A, FEATURE_LEVEL_ARM_V8_0_M, FEATURE_LEVEL_ARM_V8_0_R, FEATURE_LEVEL_ARM_V8_1_A, FEATURE_LEVEL_ARM_V8_1_M, FEATURE_LEVEL_ARM_V8_2_A, FEATURE_LEVEL_ARM_V8_3_A, FEATURE_LEVEL_ARM_V8_4_A, FEATURE_LEVEL_ARM_V8_5_A, FEATURE_LEVEL_ARM_V8_6_A, FEATURE_LEVEL_ARM_V8_7_A, FEATURE_LEVEL_ARM_V8_8_A, FEATURE_LEVEL_ARM_V8_9_A, FEATURE_LEVEL_ARM_V9_0_A, FEATURE_LEVEL_ARM_V9_1_A, FEATURE_LEVEL_ARM_V9_2_A, FEATURE_LEVEL_ARM_V9_3_A, FEATURE_LEVEL_ARM_V9_4_A, FEATURE_LEVEL_ARM_V9_5_A, NUM_FEATURE_LEVELS, FEATURE_LEVEL_UNKNOWN = -1 }
CPU feature level.
enum cpu_purpose_t { PURPOSE_GENERAL = 0, PURPOSE_PERFORMANCE, PURPOSE_EFFICIENCY, PURPOSE_LP_EFFICIENCY, PURPOSE_U_PERFORMANCE, NUM_CPU_PURPOSES }
CPU purpose.
enum hypervisor_vendor_t { HYPERVISOR_NONE = 0, HYPERVISOR_BHYVE, HYPERVISOR_HYPERV, HYPERVISOR_KVM, HYPERVISOR_PARALLELS, HYPERVISOR_QEMU, HYPERVISOR_VIRTUALBOX, HYPERVISOR_VMWARE, HYPERVISOR_XEN, NUM_HYPERVISOR_VENDORS, HYPERVISOR_UNKNOWN = -1 }
Hypervisor vendor, as guessed from the CPU_FEATURE_HYPERVISOR flag.
enum cpu_feature_t { CPU_FEATURE_FPU = 0, CPU_FEATURE_VME, CPU_FEATURE_DE, CPU_FEATURE_PSE, CPU_FEATURE_TSC, CPU_FEATURE_MSR, CPU_FEATURE_PAE, CPU_FEATURE_MCE, CPU_FEATURE_CX8, CPU_FEATURE_APIC, CPU_FEATURE_MTRR, CPU_FEATURE_SEP, CPU_FEATURE_PGE, CPU_FEATURE_MCA, CPU_FEATURE_CMOV, CPU_FEATURE_PAT, CPU_FEATURE_PSE36, CPU_FEATURE_PN, CPU_FEATURE_CLFLUSH, CPU_FEATURE_DTS, CPU_FEATURE_ACPI, CPU_FEATURE_MMX, CPU_FEATURE_FXSR, CPU_FEATURE_SSE, CPU_FEATURE_SSE2, CPU_FEATURE_SS, CPU_FEATURE_HT, CPU_FEATURE_TM, CPU_FEATURE_IA64, CPU_FEATURE_PBE, CPU_FEATURE_PNI, CPU_FEATURE_PCLMUL, CPU_FEATURE_DTS64, CPU_FEATURE_MONITOR, CPU_FEATURE_DS_CPL, CPU_FEATURE_VMX, CPU_FEATURE_SMX, CPU_FEATURE_EST, CPU_FEATURE_TM2, CPU_FEATURE_SSSE3, CPU_FEATURE_CID, CPU_FEATURE_CX16, CPU_FEATURE_XTPR, CPU_FEATURE_PDCM, CPU_FEATURE_DCA, CPU_FEATURE_SSE4_1, CPU_FEATURE_SSE4_2, CPU_FEATURE_SYSCALL, CPU_FEATURE_XD, CPU_FEATURE_MOVBE, CPU_FEATURE_POPCNT, CPU_FEATURE_AES, CPU_FEATURE_XSAVE, CPU_FEATURE_OSXSAVE, CPU_FEATURE_AVX, CPU_FEATURE_MMXEXT, CPU_FEATURE_3DNOW, CPU_FEATURE_3DNOWEXT, CPU_FEATURE_NX, CPU_FEATURE_FXSR_OPT, CPU_FEATURE_RDTSCP, CPU_FEATURE_LM, CPU_FEATURE_LAHF_LM, CPU_FEATURE_CMP_LEGACY, CPU_FEATURE_SVM, CPU_FEATURE_ABM, CPU_FEATURE_MISALIGNSSE, CPU_FEATURE_SSE4A, CPU_FEATURE_3DNOWPREFETCH, CPU_FEATURE_OSVW, CPU_FEATURE_IBS, CPU_FEATURE_SSE5, CPU_FEATURE_SKINIT, CPU_FEATURE_WDT, CPU_FEATURE_TS, CPU_FEATURE_FID, CPU_FEATURE_VID, CPU_FEATURE_TTP, CPU_FEATURE_TM_AMD, CPU_FEATURE_STC, CPU_FEATURE_100MHZSTEPS, CPU_FEATURE_HWPSTATE, CPU_FEATURE_CONSTANT_TSC, CPU_FEATURE_XOP, CPU_FEATURE_FMA3, CPU_FEATURE_FMA4, CPU_FEATURE_TBM, CPU_FEATURE_F16C, CPU_FEATURE_RDRAND, CPU_FEATURE_X2APIC, CPU_FEATURE_CPB, CPU_FEATURE_APERFMPERF, CPU_FEATURE_PFI, CPU_FEATURE_PA, CPU_FEATURE_AVX2, CPU_FEATURE_BMI1, CPU_FEATURE_BMI2, CPU_FEATURE_HLE, CPU_FEATURE_RTM, CPU_FEATURE_AVX512F, CPU_FEATURE_AVX512DQ, CPU_FEATURE_AVX512PF, CPU_FEATURE_AVX512ER, CPU_FEATURE_AVX512CD, CPU_FEATURE_SHA_NI, CPU_FEATURE_AVX512BW, CPU_FEATURE_AVX512VL, CPU_FEATURE_SGX, CPU_FEATURE_RDSEED, CPU_FEATURE_ADX, CPU_FEATURE_AVX512VNNI, CPU_FEATURE_AVX512VBMI, CPU_FEATURE_AVX512VBMI2, CPU_FEATURE_HYPERVISOR, CPU_FEATURE_SWAP, CPU_FEATURE_THUMB, CPU_FEATURE_ADVMULTU, CPU_FEATURE_ADVMULTS, CPU_FEATURE_JAZELLE, CPU_FEATURE_DEBUGV6, CPU_FEATURE_DEBUGV6P1, CPU_FEATURE_THUMB2, CPU_FEATURE_DEBUGV7, CPU_FEATURE_DEBUGV7P1, CPU_FEATURE_THUMBEE, CPU_FEATURE_DIVIDE, CPU_FEATURE_LPAE, CPU_FEATURE_PMUV1, CPU_FEATURE_PMUV2, CPU_FEATURE_ASID16, CPU_FEATURE_ADVSIMD, CPU_FEATURE_CRC32, CPU_FEATURE_CSV2_1P1, CPU_FEATURE_CSV2_1P2, CPU_FEATURE_CSV2_2, CPU_FEATURE_CSV2_3, CPU_FEATURE_DOUBLELOCK, CPU_FEATURE_ETS2, CPU_FEATURE_FP, CPU_FEATURE_MIXEDEND, CPU_FEATURE_MIXEDENDEL0, CPU_FEATURE_PMULL, CPU_FEATURE_PMUV3, CPU_FEATURE_SHA1, CPU_FEATURE_SHA256, CPU_FEATURE_NTLBPA, CPU_FEATURE_HAFDBS, CPU_FEATURE_HPDS, CPU_FEATURE_LOR, CPU_FEATURE_LSE, CPU_FEATURE_PAN, CPU_FEATURE_PMUV3P1, CPU_FEATURE_RDM, CPU_FEATURE_VHE, CPU_FEATURE_VMID16, CPU_FEATURE_AA32HPD, CPU_FEATURE_AA32I8MM, CPU_FEATURE_DPB, CPU_FEATURE_DEBUGV8P2, CPU_FEATURE_F32MM, CPU_FEATURE_F64MM, CPU_FEATURE_FP16, CPU_FEATURE_HPDS2, CPU_FEATURE_I8MM, CPU_FEATURE_IESB, CPU_FEATURE_LPA, CPU_FEATURE_LSMAOC, CPU_FEATURE_LVA, CPU_FEATURE_PAN2, CPU_FEATURE_RAS, CPU_FEATURE_SHA3, CPU_FEATURE_SHA512, CPU_FEATURE_SM3, CPU_FEATURE_SM4, CPU_FEATURE_SPE, CPU_FEATURE_SVE, CPU_FEATURE_TTCNP, CPU_FEATURE_UAO, CPU_FEATURE_XNX, CPU_FEATURE_CCIDX, CPU_FEATURE_CONSTPACFIELD, CPU_FEATURE_EPAC, CPU_FEATURE_FCMA, CPU_FEATURE_FPAC, CPU_FEATURE_FPACCOMBINE, CPU_FEATURE_JSCVT, CPU_FEATURE_LRCPC, CPU_FEATURE_PACIMP, CPU_FEATURE_PACQARMA3, CPU_FEATURE_PACQARMA5, CPU_FEATURE_PAUTH, CPU_FEATURE_SPEV1P1, CPU_FEATURE_AMUV1, CPU_FEATURE_BBM, CPU_FEATURE_DIT, CPU_FEATURE_DEBUGV8P4, CPU_FEATURE_DOTPROD, CPU_FEATURE_DOUBLEFAULT, CPU_FEATURE_FHM, CPU_FEATURE_FLAGM, CPU_FEATURE_IDST, CPU_FEATURE_LRCPC2, CPU_FEATURE_LSE2, CPU_FEATURE_MPAM, CPU_FEATURE_PMUV3P4, CPU_FEATURE_RASV1P1, CPU_FEATURE_S2FWB, CPU_FEATURE_SEL2, CPU_FEATURE_TLBIOS, CPU_FEATURE_TLBIRANGE, CPU_FEATURE_TRF, CPU_FEATURE_TTL, CPU_FEATURE_TTST, CPU_FEATURE_BTI, CPU_FEATURE_CSV2, CPU_FEATURE_CSV3, CPU_FEATURE_DPB2, CPU_FEATURE_E0PD, CPU_FEATURE_EVT, CPU_FEATURE_EXS, CPU_FEATURE_FRINTTS, CPU_FEATURE_FLAGM2, CPU_FEATURE_MTE, CPU_FEATURE_MTE2, CPU_FEATURE_PMUV3P5, CPU_FEATURE_RNG, CPU_FEATURE_RNG_TRAP, CPU_FEATURE_SB, CPU_FEATURE_SPECRES, CPU_FEATURE_SSBS, CPU_FEATURE_SSBS2, CPU_FEATURE_AA32BF16, CPU_FEATURE_AMUV1P1, CPU_FEATURE_BF16, CPU_FEATURE_DGH, CPU_FEATURE_ECV, CPU_FEATURE_FGT, CPU_FEATURE_HPMN0, CPU_FEATURE_MPAMV0P1, CPU_FEATURE_MPAMV1P1, CPU_FEATURE_MTPMU, CPU_FEATURE_PAUTH2, CPU_FEATURE_TWED, CPU_FEATURE_AFP, CPU_FEATURE_EBF16, CPU_FEATURE_HCX, CPU_FEATURE_LPA2, CPU_FEATURE_LS64, CPU_FEATURE_LS64_ACCDATA, CPU_FEATURE_LS64_V, CPU_FEATURE_MTE3, CPU_FEATURE_MTE_ASYM_FAULT, CPU_FEATURE_PAN3, CPU_FEATURE_PMUV3P7, CPU_FEATURE_RPRES, CPU_FEATURE_SPEV1P2, CPU_FEATURE_WFXT, CPU_FEATURE_XS, CPU_FEATURE_CMOW, CPU_FEATURE_DEBUGV8P8, CPU_FEATURE_HBC, CPU_FEATURE_MOPS, CPU_FEATURE_NMI, CPU_FEATURE_PMUV3P8, CPU_FEATURE_SCTLR2, CPU_FEATURE_SPEV1P3, CPU_FEATURE_TCR2, CPU_FEATURE_TIDCP1, CPU_FEATURE_ADERR, CPU_FEATURE_AIE, CPU_FEATURE_ANERR, CPU_FEATURE_ATS1A, CPU_FEATURE_CLRBHB, CPU_FEATURE_CSSC, CPU_FEATURE_DEBUGV8P9, CPU_FEATURE_DOUBLEFAULT2, CPU_FEATURE_ECBHB, CPU_FEATURE_FGT2, CPU_FEATURE_HAFT, CPU_FEATURE_LRCPC3, CPU_FEATURE_MTE4, CPU_FEATURE_MTE_ASYNC, CPU_FEATURE_MTE_CANONICAL_TAGS, CPU_FEATURE_MTE_NO_ADDRESS_TAGS, CPU_FEATURE_MTE_PERM, CPU_FEATURE_MTE_STORE_ONLY, CPU_FEATURE_MTE_TAGGED_FAR, CPU_FEATURE_PFAR, CPU_FEATURE_PMUV3_ICNTR, CPU_FEATURE_PMUV3_SS, CPU_FEATURE_PMUV3P9, CPU_FEATURE_PRFMSLC, CPU_FEATURE_RASV2, CPU_FEATURE_RPRFM, CPU_FEATURE_S1PIE, CPU_FEATURE_S1POE, CPU_FEATURE_S2PIE, CPU_FEATURE_S2POE, CPU_FEATURE_SPECRES2, CPU_FEATURE_SPE_DPFZS, CPU_FEATURE_SPEV1P4, CPU_FEATURE_SPMU, CPU_FEATURE_THE, CPU_FEATURE_SVE2, CPU_FEATURE_SVE_AES, CPU_FEATURE_SVE_BITPERM, CPU_FEATURE_SVE_PMULL128, CPU_FEATURE_SVE_SHA3, CPU_FEATURE_SVE_SM4, CPU_FEATURE_TME, CPU_FEATURE_TRBE, CPU_FEATURE_BRBE, CPU_FEATURE_RME, CPU_FEATURE_SME, CPU_FEATURE_SME_F64F64, CPU_FEATURE_SME_FA64, CPU_FEATURE_SME_I16I64, CPU_FEATURE_BRBEV1P1, CPU_FEATURE_MEC, CPU_FEATURE_SME2, CPU_FEATURE_ABLE, CPU_FEATURE_BWE, CPU_FEATURE_D128, CPU_FEATURE_EBEP, CPU_FEATURE_GCS, CPU_FEATURE_ITE, CPU_FEATURE_LSE128, CPU_FEATURE_LVA3, CPU_FEATURE_SEBEP, CPU_FEATURE_SME2P1, CPU_FEATURE_SME_F16F16, CPU_FEATURE_SVE2P1, CPU_FEATURE_SVE_B16B16, CPU_FEATURE_SYSINSTR128, CPU_FEATURE_SYSREG128, CPU_FEATURE_TRBE_EXT, CPU_FEATURE_ASID2, CPU_FEATURE_BWE2, CPU_FEATURE_CPA, CPU_FEATURE_CPA2, CPU_FEATURE_E2H0, CPU_FEATURE_E3DSE, CPU_FEATURE_ETS3, CPU_FEATURE_FAMINMAX, CPU_FEATURE_FGWTE3, CPU_FEATURE_FP8, CPU_FEATURE_FP8DOT2, CPU_FEATURE_FP8DOT4, CPU_FEATURE_FP8FMA, CPU_FEATURE_FPMR, CPU_FEATURE_HACDBS, CPU_FEATURE_HDBSS, CPU_FEATURE_LUT, CPU_FEATURE_PAUTH_LR, CPU_FEATURE_RME_GPC2, CPU_FEATURE_SME_F8F16, CPU_FEATURE_SME_F8F32, CPU_FEATURE_SME_LUTV2, CPU_FEATURE_SPMU2, CPU_FEATURE_SSVE_FP8DOT2, CPU_FEATURE_SSVE_FP8DOT4, CPU_FEATURE_SSVE_FP8FMA, CPU_FEATURE_STEP2, CPU_FEATURE_TLBIW, NUM_CPU_FEATURES }
CPU feature identifiers.
enum cpu_hint_t { CPU_HINT_SSE_SIZE_AUTH = 0, NUM_CPU_HINTS }
CPU detection hints identifiers.
enum cpu_sgx_feature_t { INTEL_SGX1, INTEL_SGX2, NUM_SGX_FEATURES }
SGX features flags.
enum cpu_error_t { ERR_OK = 0, ERR_NO_CPUID = -1, ERR_NO_RDTSC = -2, ERR_NO_MEM = -3, ERR_OPEN = -4, ERR_BADFMT = -5, ERR_NOT_IMP = -6, ERR_CPU_UNKN = -7, ERR_NO_RDMSR = -8, ERR_NO_DRIVER = -9, ERR_NO_PERMS = -10, ERR_EXTRACT = -11, ERR_HANDLE = -12, ERR_INVMSR = -13, ERR_INVCNB = -14, ERR_HANDLE_R = -15, ERR_INVRANGE = -16, ERR_NOT_FOUND = -17, ERR_IOCTL = -18, ERR_REQUEST = -19 }
Describes common library error codes.
enum cpu_msrinfo_request_t { INFO_MPERF, INFO_APERF, INFO_MIN_MULTIPLIER, INFO_CUR_MULTIPLIER, INFO_MAX_MULTIPLIER, INFO_TEMPERATURE, INFO_THROTTLING, INFO_VOLTAGE, INFO_BCLK, INFO_BUS_CLOCK }

  Functions

int cpuid_get_total_cpus (void)
Returns the total number of logical CPU threads (even if CPUID is not present).
int cpuid_present (void)
Checks if the CPUID instruction is supported.
void cpu_exec_cpuid (uint32_t eax, uint32_t *regs)
Executes the CPUID instruction.
void cpu_exec_cpuid_ext (uint32_t *regs)
Executes the CPUID instruction with the given input registers.
int cpuid_get_raw_data (struct cpu_raw_data_t *data)
Obtains the raw CPUID data from the current CPU.
int cpuid_get_raw_data_core (struct cpu_raw_data_t *data, logical_cpu_t logical_cpu)
Obtains the raw CPUID data from the specified CPU.
int cpuid_get_all_raw_data (struct cpu_raw_data_array_t *data)
Obtains the raw CPUID data from all CPUs.
int cpuid_serialize_raw_data (struct cpu_raw_data_t *data, const char *filename)
Writes the raw CPUID data to a text file.
int cpuid_serialize_all_raw_data (struct cpu_raw_data_array_t *data, const char *filename)
Writes all the raw CPUID data to a text file.
int cpuid_deserialize_raw_data (struct cpu_raw_data_t *data, const char *filename)
Reads raw CPUID data from file.
int cpuid_deserialize_all_raw_data (struct cpu_raw_data_array_t *data, const char *filename)
Reads all raw CPUID data from file.
int cpu_identify (struct cpu_raw_data_t *raw, struct cpu_id_t *data)
Identifies the CPU.
int cpu_identify_all (struct cpu_raw_data_array_t *raw_array, struct system_id_t *system)
Identifies all the CPUs.
int cpu_request_core_type (cpu_purpose_t purpose, struct cpu_raw_data_array_t *raw_array, struct cpu_id_t *data)
Identifies a given CPU type.
const char * cpu_architecture_str (cpu_architecture_t architecture)
Returns the short textual representation of a CPU architecture.
const char * cpu_feature_level_str (cpu_feature_level_t level)
Returns the short textual representation of a CPU feature level.
const char * cpu_purpose_str (cpu_purpose_t purpose)
Returns the short textual representation of a CPU purpose.
char * affinity_mask_str_r (cpu_affinity_mask_t *affinity_mask, char *buffer, uint32_t buffer_len)
Returns textual representation of a CPU affinity mask (thread-safe)
char * affinity_mask_str (cpu_affinity_mask_t *affinity_mask)
Returns textual representation of a CPU affinity mask.
const char * cpu_feature_str (cpu_feature_t feature)
Returns the short textual representation of a CPU flag.
const char * cpuid_error (void)
Returns textual description of the last error.
void cpu_rdtsc (uint64_t *result)
Executes RDTSC.
void cpu_tsc_mark (struct cpu_mark_t *mark)
Store TSC and timing info.
void cpu_tsc_unmark (struct cpu_mark_t *mark)
Calculate TSC and timing difference.
int cpu_clock_by_mark (struct cpu_mark_t *mark)
Calculates the CPU clock.
int cpu_clock_by_os (void)
Returns the CPU clock, as reported by the OS.
int cpu_clock_measure (int millis, int quad_check)
Measure the CPU clock frequency.
int cpu_clock_by_ic (int millis, int runs)
Measure the CPU clock frequency using instruction-counting.
int cpu_clock_by_tsc (struct cpu_raw_data_t *raw)
Measure the CPU clock frequency using TSC frequency from CPUID.
int cpu_clock (void)
Get the CPU clock frequency (all-in-one method)
struct cpu_epc_t cpuid_get_epc (int index, const struct cpu_raw_data_t *raw)
Fetches information about an EPC (Enclave Page Cache) area.
const char * cpuid_lib_version (void)
Returns the libcpuid version.
libcpuid_warn_fn_t cpuid_set_warn_function (libcpuid_warn_fn_t warn_fun)
Sets the warning print function.
void cpuid_set_verbosiness_level (int level)
Sets the verbosiness level.
cpu_vendor_t cpuid_get_vendor (void)
Obtains the CPU vendor from CPUID from the current CPU.
hypervisor_vendor_t cpuid_get_hypervisor (struct cpu_raw_data_t *raw, struct cpu_id_t *data)
Obtains the hypervisor vendor from CPUID from the current CPU.
void cpuid_get_cpu_list (cpu_vendor_t vendor, struct cpu_list_t *list)
Gets a list of all known CPU names from a specific vendor.
void cpuid_free_cpu_list (struct cpu_list_t *list)
Frees a CPU list.
void cpuid_free_raw_data_array (struct cpu_raw_data_array_t *raw_array)
Frees a raw array.
void cpuid_free_system_id (struct system_id_t *system)
Frees a system ID type.
struct msr_driver_t * cpu_msr_driver_open (void)
Starts/opens a driver, needed to read MSRs (Model Specific Registers)
struct msr_driver_t * cpu_msr_driver_open_core (unsigned core_num)
Similar to cpu_msr_driver_open, but accept one parameter.
int cpu_rdmsr (struct msr_driver_t *handle, uint32_t msr_index, uint64_t *result)
Reads a Model-Specific Register (MSR)
int cpu_rdmsr_range (struct msr_driver_t *handle, uint32_t msr_index, uint8_t highbit, uint8_t lowbit, uint64_t *result)
Similar to cpu_rdmsr, but extract a range of bits.
int cpu_msrinfo (struct msr_driver_t *handle, cpu_msrinfo_request_t which)
Reads extended CPU information from Model-Specific Registers.
int msr_serialize_raw_data (struct msr_driver_t *handle, const char *filename)
Writes the raw MSR data to a text file.
int cpu_msr_driver_close (struct msr_driver_t *handle)
Closes an open MSR driver.

Detailed Description

LibCPUID provides CPU identification.

Enumeration Type Documentation

  enum cpu_architecture_t

CPU architecture.

Enumerator

ARCHITECTURE_X86
    x86 CPU

ARCHITECTURE_ARM
    ARM CPU

NUM_CPU_ARCHITECTURES
    Valid CPU architecture ids: 0..NUM_CPU_ARCHITECTURES - 1

  enum cpu_error_t

Describes common library error codes.

Enumerator

ERR_OK
    No error

ERR_NO_CPUID
    CPUID instruction is not supported

ERR_NO_RDTSC
    RDTSC instruction is not supported

ERR_NO_MEM
    Memory allocation failed

ERR_OPEN
    File open operation failed

ERR_BADFMT
    Bad file format

ERR_NOT_IMP
    Not implemented

ERR_CPU_UNKN
    Unsupported processor

ERR_NO_RDMSR
    RDMSR instruction is not supported

ERR_NO_DRIVER
    RDMSR driver error (generic)

ERR_NO_PERMS
    No permissions to install RDMSR driver

ERR_EXTRACT
    Cannot extract RDMSR driver (read only media?)

ERR_HANDLE
    Bad handle

ERR_INVMSR
    Invalid MSR

ERR_INVCNB
    Invalid core number

ERR_HANDLE_R
    Error on handle read

ERR_INVRANGE
    Invalid given range

ERR_NOT_FOUND
    Requested type not found

ERR_IOCTL
    Error on ioctl

ERR_REQUEST
    Invalid request

  enum cpu_feature_level_t

CPU feature level.

Enumerator

FEATURE_LEVEL_I386
    i386

FEATURE_LEVEL_I486
    i486

FEATURE_LEVEL_I586
    i586

FEATURE_LEVEL_I686
    i686

FEATURE_LEVEL_X86_64_V1
    x86-64-v1

FEATURE_LEVEL_X86_64_V2
    x86-64-v2

FEATURE_LEVEL_X86_64_V3
    x86-64-v3

FEATURE_LEVEL_X86_64_V4
    x86-64-v4

FEATURE_LEVEL_ARM_V1
    ARMv1

FEATURE_LEVEL_ARM_V2
    ARMv2

FEATURE_LEVEL_ARM_V3
    ARMv3

FEATURE_LEVEL_ARM_V4
    ARMv4

FEATURE_LEVEL_ARM_V4T
    ARMv4T

FEATURE_LEVEL_ARM_V5
    ARMv5 (obsolete)

FEATURE_LEVEL_ARM_V5T
    ARMv5T

FEATURE_LEVEL_ARM_V5TE
    ARMv5TE

FEATURE_LEVEL_ARM_V5TEJ
    ARMv5TEJ

FEATURE_LEVEL_ARM_V6
    ARMv6

FEATURE_LEVEL_ARM_V6_M
    ARMv6-M

FEATURE_LEVEL_ARM_V7_A
    ARMv7-A

FEATURE_LEVEL_ARM_V7_M
    ARMv7-M

FEATURE_LEVEL_ARM_V7_R
    ARMv7-R

FEATURE_LEVEL_ARM_V7E_M
    ARMv7E-M

FEATURE_LEVEL_ARM_V8_0_A
    ARMv8.0-A

FEATURE_LEVEL_ARM_V8_0_M
    ARMv8.0-M

FEATURE_LEVEL_ARM_V8_0_R
    ARMv8.0-R

FEATURE_LEVEL_ARM_V8_1_A
    ARMv8.1-A

FEATURE_LEVEL_ARM_V8_1_M
    ARMv8.1-M

FEATURE_LEVEL_ARM_V8_2_A
    ARMv8.2-A

FEATURE_LEVEL_ARM_V8_3_A
    ARMv8.3-A

FEATURE_LEVEL_ARM_V8_4_A
    ARMv8.4-A

FEATURE_LEVEL_ARM_V8_5_A
    ARMv8.5-A

FEATURE_LEVEL_ARM_V8_6_A
    ARMv8.6-A

FEATURE_LEVEL_ARM_V8_7_A
    ARMv8.7-A

FEATURE_LEVEL_ARM_V8_8_A
    ARMv8.8-A

FEATURE_LEVEL_ARM_V8_9_A
    ARMv8.9-A

FEATURE_LEVEL_ARM_V9_0_A
    ARMv9.0-A

FEATURE_LEVEL_ARM_V9_1_A
    ARMv9.1-A

FEATURE_LEVEL_ARM_V9_2_A
    ARMv9.2-A

FEATURE_LEVEL_ARM_V9_3_A
    ARMv9.3-A

FEATURE_LEVEL_ARM_V9_4_A
    ARMv9.4-A

FEATURE_LEVEL_ARM_V9_5_A
    ARMv9.5-A

NUM_FEATURE_LEVELS
    Valid feature level ids: 0..NUM_FEATURE_LEVELS - 1

  enum cpu_feature_t

CPU feature identifiers. Usage:

...
struct cpu_raw_data_t raw;
struct cpu_id_t id;
if (cpuid_get_raw_data(&raw) == 0 && cpu_identify(&raw, &id) == 0) {
    if (id.flags[CPU_FEATURE_SSE2]) {
        // The CPU has SSE2...
        ...
    } else {
        // no SSE2
    }
} else {
  // processor cannot be determined.
}

Enumerator

CPU_FEATURE_FPU
    Floating point unit

CPU_FEATURE_VME
    Virtual mode extension

CPU_FEATURE_DE
    Debugging extension

CPU_FEATURE_PSE
    Page size extension

CPU_FEATURE_TSC
    Time-stamp counter

CPU_FEATURE_MSR
    Model-specific regsisters, RDMSR/WRMSR supported

CPU_FEATURE_PAE
    Physical address extension

CPU_FEATURE_MCE
    Machine check exception

CPU_FEATURE_CX8
    CMPXCHG8B instruction supported

CPU_FEATURE_APIC
    APIC support

CPU_FEATURE_MTRR
    Memory type range registers

CPU_FEATURE_SEP
    SYSENTER / SYSEXIT instructions supported

CPU_FEATURE_PGE
    Page global enable

CPU_FEATURE_MCA
    Machine check architecture

CPU_FEATURE_CMOV
    CMOVxx instructions supported

CPU_FEATURE_PAT
    Page attribute table

CPU_FEATURE_PSE36
    36-bit page address extension

CPU_FEATURE_PN
    Processor serial # implemented (Intel P3 only)

CPU_FEATURE_CLFLUSH
    CLFLUSH instruction supported

CPU_FEATURE_DTS
    Debug store supported

CPU_FEATURE_ACPI
    ACPI support (power states)

CPU_FEATURE_MMX
    MMX instruction set supported

CPU_FEATURE_FXSR
    FXSAVE / FXRSTOR supported

CPU_FEATURE_SSE
    Streaming-SIMD Extensions (SSE) supported

CPU_FEATURE_SSE2
    SSE2 instructions supported

CPU_FEATURE_SS
    Self-snoop

CPU_FEATURE_HT
    Hyper-threading supported (but might be disabled)

CPU_FEATURE_TM
    Thermal monitor

CPU_FEATURE_IA64
    IA64 supported (Itanium only)

CPU_FEATURE_PBE
    Pending-break enable

CPU_FEATURE_PNI
    PNI (SSE3) instructions supported

CPU_FEATURE_PCLMUL
    PCLMULQDQ instruction supported

CPU_FEATURE_DTS64
    64-bit Debug store supported

CPU_FEATURE_MONITOR
    MONITOR / MWAIT supported

CPU_FEATURE_DS_CPL
    CPL Qualified Debug Store

CPU_FEATURE_VMX
    Virtualization technology supported

CPU_FEATURE_SMX
    Safer mode exceptions

CPU_FEATURE_EST
    Enhanced SpeedStep

CPU_FEATURE_TM2
    Thermal monitor 2

CPU_FEATURE_SSSE3
    SSSE3 instructionss supported (this is different from SSE3!)

CPU_FEATURE_CID
    Context ID supported

CPU_FEATURE_CX16
    CMPXCHG16B instruction supported

CPU_FEATURE_XTPR
    Send Task Priority Messages disable

CPU_FEATURE_PDCM
    Performance capabilities MSR supported

CPU_FEATURE_DCA
    Direct cache access supported

CPU_FEATURE_SSE4_1
    SSE 4.1 instructions supported

CPU_FEATURE_SSE4_2
    SSE 4.2 instructions supported

CPU_FEATURE_SYSCALL
    SYSCALL / SYSRET instructions supported

CPU_FEATURE_XD
    Execute disable bit supported

CPU_FEATURE_MOVBE
    MOVBE instruction supported

CPU_FEATURE_POPCNT
    POPCNT instruction supported

CPU_FEATURE_AES
    AES* instructions supported

CPU_FEATURE_XSAVE
    XSAVE/XRSTOR/etc instructions supported

CPU_FEATURE_OSXSAVE
    non-privileged copy of OSXSAVE supported

CPU_FEATURE_AVX
    Advanced vector extensions supported

CPU_FEATURE_MMXEXT
    AMD MMX-extended instructions supported

CPU_FEATURE_3DNOW
    AMD 3DNow! instructions supported

CPU_FEATURE_3DNOWEXT
    AMD 3DNow! extended instructions supported

CPU_FEATURE_NX
    No-execute bit supported

CPU_FEATURE_FXSR_OPT
    FFXSR: FXSAVE and FXRSTOR optimizations

CPU_FEATURE_RDTSCP
    RDTSCP instruction supported (AMD-only)

CPU_FEATURE_LM
    Long mode (x86_64/EM64T) supported

CPU_FEATURE_LAHF_LM
    LAHF/SAHF supported in 64-bit mode

CPU_FEATURE_CMP_LEGACY
    core multi-processing legacy mode

CPU_FEATURE_SVM
    AMD Secure virtual machine

CPU_FEATURE_ABM
    LZCNT instruction support

CPU_FEATURE_MISALIGNSSE
    Misaligned SSE supported

CPU_FEATURE_SSE4A
    SSE 4a from AMD

CPU_FEATURE_3DNOWPREFETCH
    PREFETCH/PREFETCHW support

CPU_FEATURE_OSVW
    OS Visible Workaround (AMD)

CPU_FEATURE_IBS
    Instruction-based sampling

CPU_FEATURE_SSE5
    SSE 5 instructions supported (deprecated, will never be 1)

CPU_FEATURE_SKINIT
    SKINIT / STGI supported

CPU_FEATURE_WDT
    Watchdog timer support

CPU_FEATURE_TS
    Temperature sensor

CPU_FEATURE_FID
    Frequency ID control

CPU_FEATURE_VID
    Voltage ID control

CPU_FEATURE_TTP
    THERMTRIP

CPU_FEATURE_TM_AMD
    AMD-specified hardware thermal control

CPU_FEATURE_STC
    Software thermal control

CPU_FEATURE_100MHZSTEPS
    100 MHz multiplier control

CPU_FEATURE_HWPSTATE
    Hardware P-state control

CPU_FEATURE_CONSTANT_TSC
    TSC ticks at constant rate

CPU_FEATURE_XOP
    The XOP instruction set (same as the old CPU_FEATURE_SSE5)

CPU_FEATURE_FMA3
    The FMA3 instruction set

CPU_FEATURE_FMA4
    The FMA4 instruction set

CPU_FEATURE_TBM
    Trailing bit manipulation instruction support

CPU_FEATURE_F16C
    16-bit FP convert instruction support

CPU_FEATURE_RDRAND
    RdRand instruction

CPU_FEATURE_X2APIC
    x2APIC, APIC_BASE.EXTD, MSRs 0000_0800h...0000_0BFFh 64-bit ICR (+030h but not +031h), no DFR (+00Eh), SELF_IPI (+040h) also see standard level 0000_000Bh

CPU_FEATURE_CPB
    Core performance boost

CPU_FEATURE_APERFMPERF
    MPERF/APERF MSRs support

CPU_FEATURE_PFI
    Processor Feedback Interface support

CPU_FEATURE_PA
    Processor accumulator

CPU_FEATURE_AVX2
    AVX2 instructions

CPU_FEATURE_BMI1
    BMI1 instructions

CPU_FEATURE_BMI2
    BMI2 instructions

CPU_FEATURE_HLE
    Hardware Lock Elision prefixes

CPU_FEATURE_RTM
    Restricted Transactional Memory instructions

CPU_FEATURE_AVX512F
    AVX-512 Foundation

CPU_FEATURE_AVX512DQ
    AVX-512 Double/Quad granular insns

CPU_FEATURE_AVX512PF
    AVX-512 Prefetch

CPU_FEATURE_AVX512ER
    AVX-512 Exponential/Reciprocal

CPU_FEATURE_AVX512CD
    AVX-512 Conflict detection

CPU_FEATURE_SHA_NI
    SHA-1/SHA-256 instructions

CPU_FEATURE_AVX512BW
    AVX-512 Byte/Word granular insns

CPU_FEATURE_AVX512VL
    AVX-512 128/256 vector length extensions

CPU_FEATURE_SGX
    SGX extensions. Non-autoritative, check cpu_id_t::sgx::present to verify presence

CPU_FEATURE_RDSEED
    RDSEED instruction

CPU_FEATURE_ADX
    ADX extensions (arbitrary precision)

CPU_FEATURE_AVX512VNNI
    AVX-512 Vector Neural Network Instructions

CPU_FEATURE_AVX512VBMI
    AVX-512 Vector Bit ManipulationInstructions (version 1)

CPU_FEATURE_AVX512VBMI2
    AVX-512 Vector Bit ManipulationInstructions (version 2)

CPU_FEATURE_HYPERVISOR
    Hypervisor present (always zero on physical CPUs)

CPU_FEATURE_SWAP
    ARM: Swap instructions in the ARM instruction set

CPU_FEATURE_THUMB
    ARM: Thumb instruction set support

CPU_FEATURE_ADVMULTU
    ARM: Advanced unsigned Multiply instructions

CPU_FEATURE_ADVMULTS
    ARM: Advanced signed Multiply instructions

CPU_FEATURE_JAZELLE
    ARM: Jazelle extension support

CPU_FEATURE_DEBUGV6
    ARM: Support for v6 Debug architecture

CPU_FEATURE_DEBUGV6P1
    ARM: Support for v6.1 Debug architecture

CPU_FEATURE_THUMB2
    ARM: Thumb-2, instruction set support

CPU_FEATURE_DEBUGV7
    ARM: Support for v7 Debug architecture

CPU_FEATURE_DEBUGV7P1
    ARM: Support for v7.1 Debug architecture

CPU_FEATURE_THUMBEE
    ARM: ThumbEE instruction set support

CPU_FEATURE_DIVIDE
    ARM: Divide instructions

CPU_FEATURE_LPAE
    ARM: Large Physical Address Extension

CPU_FEATURE_PMUV1
    ARM: PMU extension version 1

CPU_FEATURE_PMUV2
    ARM: PMU extension version 2

CPU_FEATURE_ASID16
    ARM: 16 bit ASID

CPU_FEATURE_ADVSIMD
    ARM: Advanced SIMD Extension

CPU_FEATURE_CRC32
    ARM: CRC32 instructions

CPU_FEATURE_CSV2_1P1
    ARM: Cache Speculation Variant 2

CPU_FEATURE_CSV2_1P2
    ARM: Cache Speculation Variant 2 version 1.2

CPU_FEATURE_CSV2_2
    ARM: Cache Speculation Variant 2 version 2

CPU_FEATURE_CSV2_3
    ARM: Cache Speculation Variant 2 version 3

CPU_FEATURE_DOUBLELOCK
    ARM: Double Lock

CPU_FEATURE_ETS2
    ARM: Enhanced Translation Synchronization

CPU_FEATURE_FP
    ARM: Floating Point extensions

CPU_FEATURE_MIXEDEND
    ARM: Mixed-endian support

CPU_FEATURE_MIXEDENDEL0
    ARM: Mixed-endian support at EL0

CPU_FEATURE_PMULL
    ARM: Advanced SIMD PMULL instructions

CPU_FEATURE_PMUV3
    ARM: PMU extension version 3

CPU_FEATURE_SHA1
    ARM: Advanced SIMD SHA1 instructions

CPU_FEATURE_SHA256
    ARM: Advanced SIMD SHA256 instructions

CPU_FEATURE_NTLBPA
    ARM: Intermediate caching of translation table walks

CPU_FEATURE_HAFDBS
    ARM: Hardware management of the Access flag and dirty state

CPU_FEATURE_HPDS
    ARM: Hierarchical permission disables in translations tables

CPU_FEATURE_LOR
    ARM: Limited ordering regions

CPU_FEATURE_LSE
    ARM: Large System Extensions

CPU_FEATURE_PAN
    ARM: Privileged access never

CPU_FEATURE_PMUV3P1
    ARM: Armv8.1 PMU extensions

CPU_FEATURE_RDM
    ARM: Advanced SIMD rounding double multiply accumulate instructions

CPU_FEATURE_VHE
    ARM: Virtualization Host Extensions

CPU_FEATURE_VMID16
    ARM: 16-bit VMID

CPU_FEATURE_AA32HPD
    ARM: AArch32 Hierarchical permission disables

CPU_FEATURE_AA32I8MM
    ARM: AArch32 Int8 matrix multiplication instructions

CPU_FEATURE_DPB
    ARM: DC CVAP instruction

CPU_FEATURE_DEBUGV8P2
    ARM: Debug v8.2

CPU_FEATURE_F32MM
    ARM: Single-precision Matrix Multiplication

CPU_FEATURE_F64MM
    ARM: Double-precision Matrix Multiplication

CPU_FEATURE_FP16
    ARM: Half-precision floating-point data processing

CPU_FEATURE_HPDS2
    ARM: Hierarchical permission disables

CPU_FEATURE_I8MM
    ARM: AArch64 Int8 matrix multiplication instructions

CPU_FEATURE_IESB
    ARM: Implicit Error Synchronization event

CPU_FEATURE_LPA
    ARM: Large PA and IPA support

CPU_FEATURE_LSMAOC
    ARM: AArch32 Load/Store Multiple instruction atomicity and ordering controls

CPU_FEATURE_LVA
    ARM: Large VA support

CPU_FEATURE_PAN2
    ARM: AT S1E1R and AT S1E1W instruction variants affected by PSTATE.PAN

CPU_FEATURE_RAS
    ARM: Reliability, Availability and Serviceability (RAS) Extension

CPU_FEATURE_SHA3
    ARM: Advanced SIMD SHA3 instructions

CPU_FEATURE_SHA512
    ARM: Advanced SIMD SHA512 instructions

CPU_FEATURE_SM3
    ARM: Advanced SIMD SM3 instructions

CPU_FEATURE_SM4
    ARM: Advanced SIMD SM4 instructions

CPU_FEATURE_SPE
    ARM: Statistical Profiling Extension

CPU_FEATURE_SVE
    ARM: Scalable Vector Extension

CPU_FEATURE_TTCNP
    ARM: Translation table Common not private translations

CPU_FEATURE_UAO
    ARM: Unprivileged Access Override control

CPU_FEATURE_XNX
    ARM: Translation table stage 2 Unprivileged Execute-never

CPU_FEATURE_CCIDX
    ARM: Extended cache index

CPU_FEATURE_CONSTPACFIELD
    ARM: PAC algorithm enhancement

CPU_FEATURE_EPAC
    ARM: Enhanced pointer authentication

CPU_FEATURE_FCMA
    ARM: Floating-point complex number instructions

CPU_FEATURE_FPAC
    ARM: Faulting on AUT* instructions

CPU_FEATURE_FPACCOMBINE
    ARM: Faulting on combined pointer authentication instructions

CPU_FEATURE_JSCVT
    ARM: JavaScript conversion instructions

CPU_FEATURE_LRCPC
    ARM: Load-Acquire RCpc instructions

CPU_FEATURE_PACIMP
    ARM: Pointer authentication - IMPLEMENTATION DEFINED algorithm

CPU_FEATURE_PACQARMA3
    ARM: Pointer authentication - QARMA3 algorithm

CPU_FEATURE_PACQARMA5
    ARM: Pointer authentication - QARMA5 algorithm

CPU_FEATURE_PAUTH
    ARM: Pointer authentication

CPU_FEATURE_SPEV1P1
    ARM: Statistical Profiling Extension version 1

CPU_FEATURE_AMUV1
    ARM: Activity Monitors Extension version 1

CPU_FEATURE_BBM
    ARM: Translation table break-before-make levels

CPU_FEATURE_DIT
    ARM: Data Independent Timing instructions

CPU_FEATURE_DEBUGV8P4
    ARM: Debug v8.4

CPU_FEATURE_DOTPROD
    ARM: Advanced SIMD dot product instructions

CPU_FEATURE_DOUBLEFAULT
    ARM: Double Fault Extension

CPU_FEATURE_FHM
    ARM: Floating-point half-precision to single-precision multiply-add instructions

CPU_FEATURE_FLAGM
    ARM: Condition flag manipulation instructions

CPU_FEATURE_IDST
    ARM: ID space trap handling

CPU_FEATURE_LRCPC2
    ARM: Load-Acquire RCpc instructions version 2

CPU_FEATURE_LSE2
    ARM: Large System Extensions version 2

CPU_FEATURE_MPAM
    ARM: Memory Partitioning and Monitoring Extension

CPU_FEATURE_PMUV3P4
    ARM: Arm8.4 PMU extensions

CPU_FEATURE_RASV1P1
    ARM: RAS extension v1.1

CPU_FEATURE_S2FWB
    ARM: Stage 2 forced Write-Back

CPU_FEATURE_SEL2
    ARM: Secure EL2

CPU_FEATURE_TLBIOS
    ARM: TLB invalidate instructions in Outer Shareable domain

CPU_FEATURE_TLBIRANGE
    ARM: TLB invalidate range instructions

CPU_FEATURE_TRF
    ARM: Self-hosted Trace extensions

CPU_FEATURE_TTL
    ARM: Translation Table Level

CPU_FEATURE_TTST
    ARM: Small translation tables

CPU_FEATURE_BTI
    ARM: Branch Target Identification

CPU_FEATURE_CSV2
    ARM: Cache Speculation Variant 2

CPU_FEATURE_CSV3
    ARM: Cache Speculation Variant 3

CPU_FEATURE_DPB2
    ARM: DC CVADP instruction

CPU_FEATURE_E0PD
    ARM: Preventing EL0 access to halves of address maps

CPU_FEATURE_EVT
    ARM: Enhanced Virtualization Traps

CPU_FEATURE_EXS
    ARM: Context synchronization and exception handling

CPU_FEATURE_FRINTTS
    ARM: Floating-point to integer instructions

CPU_FEATURE_FLAGM2
    ARM: Enhancements to flag manipulation instructions

CPU_FEATURE_MTE
    ARM: Memory Tagging Extension

CPU_FEATURE_MTE2
    ARM: Memory Tagging Extension

CPU_FEATURE_PMUV3P5
    ARM: Arm8.5 PMU extensions

CPU_FEATURE_RNG
    ARM: Random number generator

CPU_FEATURE_RNG_TRAP
    ARM: Trapping support for RNDR/RNDRRS

CPU_FEATURE_SB
    ARM: Speculation Barrier

CPU_FEATURE_SPECRES
    ARM: Speculation restriction instructions

CPU_FEATURE_SSBS
    ARM: Speculative Store Bypass Safe

CPU_FEATURE_SSBS2
    ARM: MRS and MSR instructions for SSBS version 2

CPU_FEATURE_AA32BF16
    ARM: AArch32 BFloat16 instructions

CPU_FEATURE_AMUV1P1
    ARM: Activity Monitors Extension version 1.1

CPU_FEATURE_BF16
    ARM: AArch64 BFloat16 instructions

CPU_FEATURE_DGH
    ARM: Data Gathering Hint

CPU_FEATURE_ECV
    ARM: Enhanced Counter Virtualization

CPU_FEATURE_FGT
    ARM: Fine Grain Traps

CPU_FEATURE_HPMN0
    ARM: Setting of MDCR_EL2.HPMN to zero

CPU_FEATURE_MPAMV0P1
    ARM: Memory Partitioning and Monitoring extension version 0.1

CPU_FEATURE_MPAMV1P1
    ARM: Memory Partitioning and Monitoring extension version 1.1

CPU_FEATURE_MTPMU
    ARM: Multi-threaded PMU extensions

CPU_FEATURE_PAUTH2
    ARM: Enhancements to pointer authentication

CPU_FEATURE_TWED
    ARM: Delayed Trapping of WFE

CPU_FEATURE_AFP
    ARM: Alternate floating-point behavior

CPU_FEATURE_EBF16
    ARM: AArch64 Extended BFloat16 behaviors

CPU_FEATURE_HCX
    ARM: Support for the HCRX_EL2 register

CPU_FEATURE_LPA2
    ARM: Larger physical address for 4KB and 16KB translation granules

CPU_FEATURE_LS64
    ARM: Support for 64-byte loads and stores without status

CPU_FEATURE_LS64_ACCDATA
    ARM: Support for 64-byte EL0 stores with status

CPU_FEATURE_LS64_V
    ARM: Support for 64-byte stores with status

CPU_FEATURE_MTE3
    ARM: MTE Asymmetric Fault Handling

CPU_FEATURE_MTE_ASYM_FAULT
    ARM: Memory tagging asymmetric faults

CPU_FEATURE_PAN3
    ARM: Support for SCTLR_ELx.EPAN

CPU_FEATURE_PMUV3P7
    ARM: Armv8.7 PMU extensions

CPU_FEATURE_RPRES
    ARM: Increased precision of FRECPE and FRSQRTE

CPU_FEATURE_SPEV1P2
    ARM: Statistical Profiling Extensions version 1.2

CPU_FEATURE_WFXT
    ARM: WFE and WFI instructions with timeout

CPU_FEATURE_XS
    ARM: XS attribute

CPU_FEATURE_CMOW
    ARM: Control for cache maintenance permission

CPU_FEATURE_DEBUGV8P8
    ARM: Debug v8.8

CPU_FEATURE_HBC
    ARM: Hinted conditional branches

CPU_FEATURE_MOPS
    ARM: Standardization of memory operations

CPU_FEATURE_NMI
    ARM: Non-maskable Interrupts

CPU_FEATURE_PMUV3P8
    ARM: Armv8.8 PMU extensions

CPU_FEATURE_SCTLR2
    ARM: Extension to SCTLR_ELx

CPU_FEATURE_SPEV1P3
    ARM: Statistical Profiling Extensions version 1.3

CPU_FEATURE_TCR2
    ARM: Support for TCR2_ELx

CPU_FEATURE_TIDCP1
    ARM: EL0 use of IMPLEMENTATION DEFINED functionality

CPU_FEATURE_ADERR
    ARM: Asynchronous Device Error Exceptions

CPU_FEATURE_AIE
    ARM: Memory Attribute Index Enhancement

CPU_FEATURE_ANERR
    ARM: Asynchronous Normal Error Exceptions

CPU_FEATURE_ATS1A
    ARM: Address Translation operations that ignore stage 1 permissions

CPU_FEATURE_CLRBHB
    ARM: Support for Clear Branch History instruction

CPU_FEATURE_CSSC
    ARM: Common Short Sequence Compression instructions

CPU_FEATURE_DEBUGV8P9
    ARM: Debug v8.9

CPU_FEATURE_DOUBLEFAULT2
    ARM: Double Fault Extension v2

CPU_FEATURE_ECBHB
    ARM: Exploitative control using branch history information

CPU_FEATURE_FGT2
    ARM: Fine-grained traps 2

CPU_FEATURE_HAFT
    ARM: Hardware managed Access Flag for Table descriptors

CPU_FEATURE_LRCPC3
    ARM: Load-Acquire RCpc instructions version 3

CPU_FEATURE_MTE4
    ARM: Enhanced Memory Tagging Extension

CPU_FEATURE_MTE_ASYNC
    ARM: Asynchronous reporting of Tag Check Fault

CPU_FEATURE_MTE_CANONICAL_TAGS
    ARM: Canonical Tag checking for Untagged memory

CPU_FEATURE_MTE_NO_ADDRESS_TAGS
    ARM: Memory tagging with Address tagging disabled

CPU_FEATURE_MTE_PERM
    ARM: Allocation tag access permission

CPU_FEATURE_MTE_STORE_ONLY
    ARM: Store-only Tag Checking

CPU_FEATURE_MTE_TAGGED_FAR
    ARM: FAR_ELx on a Tag Check Fault

CPU_FEATURE_PFAR
    ARM: Physical Fault Address Register Extension

CPU_FEATURE_PMUV3_ICNTR
    ARM: Fixed-function instruction counter

CPU_FEATURE_PMUV3_SS
    ARM: PMU Snapshot extension

CPU_FEATURE_PMUV3P9
    ARM: Armv8.9 PMU extensions

CPU_FEATURE_PRFMSLC
    ARM: SLC target support for PRFM instructions

CPU_FEATURE_RASV2
    ARM: RAS Extension v2

CPU_FEATURE_RPRFM
    ARM: Support for Range Prefetch Memory instruction

CPU_FEATURE_S1PIE
    ARM: Stage 1 permission indirections

CPU_FEATURE_S1POE
    ARM: Stage 1 permission overlays

CPU_FEATURE_S2PIE
    ARM: Stage 2 permission indirections

CPU_FEATURE_S2POE
    ARM: Stage 2 permission overlays

CPU_FEATURE_SPECRES2
    ARM: Enhanced speculation restriction instructions

CPU_FEATURE_SPE_DPFZS
    ARM: Disable Cycle Counter on SPE Freeze

CPU_FEATURE_SPEV1P4
    ARM: Statistical Profiling Extension version 1.4

CPU_FEATURE_SPMU
    ARM: System Performance Monitors Extension

CPU_FEATURE_THE
    ARM: Translation Hardening Extension

CPU_FEATURE_SVE2
    ARM: Scalable Vector Extension version 2

CPU_FEATURE_SVE_AES
    ARM: Scalable Vector AES instructions

CPU_FEATURE_SVE_BITPERM
    ARM: Scalable Vector Bit Permutes instructions

CPU_FEATURE_SVE_PMULL128
    ARM: SVE single-vector Advanced Encryption Standard and 128-bit polynomial multiply long instructions

CPU_FEATURE_SVE_SHA3
    ARM: Scalable Vector SHA3 instructions

CPU_FEATURE_SVE_SM4
    ARM: Scalable Vector SM4 instructions

CPU_FEATURE_TME
    ARM: Transactional Memory Extension

CPU_FEATURE_TRBE
    ARM: Trace Buffer Extension

CPU_FEATURE_BRBE
    ARM: Branch Record Buffer Extension

CPU_FEATURE_RME
    ARM: Realm Management Extension

CPU_FEATURE_SME
    ARM: Scalable Matrix Extension

CPU_FEATURE_SME_F64F64
    ARM: Double-precision floating-point outer product instructions

CPU_FEATURE_SME_FA64
    ARM: Full A64 instruction set support in Streaming SVE mode

CPU_FEATURE_SME_I16I64
    ARM: 16-bit to 64-bit integer widening outer product instructions

CPU_FEATURE_BRBEV1P1
    ARM: Branch Record Buffer Extension version 1.1

CPU_FEATURE_MEC
    ARM: Memory Encryption Contexts

CPU_FEATURE_SME2
    ARM: Scalable Matrix Extensions version 2

CPU_FEATURE_ABLE
    ARM: Address Breakpoint Linking Extension

CPU_FEATURE_BWE
    ARM: Breakpoint and watchpoint enhancements

CPU_FEATURE_D128
    ARM: 128-bit Translation Tables, 56 bit PA

CPU_FEATURE_EBEP
    ARM: Exception-based Event Profiling

CPU_FEATURE_GCS
    ARM: Guarded Control Stack Extension

CPU_FEATURE_ITE
    ARM: Instrumentation Trace Extension

CPU_FEATURE_LSE128
    ARM: 128-bit Atomics

CPU_FEATURE_LVA3
    ARM: 56-bit VA

CPU_FEATURE_SEBEP
    ARM: Synchronous Exception-based Event Profiling

CPU_FEATURE_SME2P1
    ARM: Scalable Matrix Extension version 2.1

CPU_FEATURE_SME_F16F16
    ARM: Non-widening half-precision FP16 to FP16 arithmetic for SME2

CPU_FEATURE_SVE2P1
    ARM: Scalable Vector Extensions version 2.1

CPU_FEATURE_SVE_B16B16
    ARM: Non-widening BFloat16 to BFloat16 arithmetic for SVE2 and SME2

CPU_FEATURE_SYSINSTR128
    ARM: 128-bit System instructions

CPU_FEATURE_SYSREG128
    ARM: 128-bit System registers

CPU_FEATURE_TRBE_EXT
    ARM: Trace Buffer external mode

CPU_FEATURE_ASID2
    ARM: Support for concurrent use of two ASIDs

CPU_FEATURE_BWE2
    ARM: Breakpoint and watchpoint enhancements 2

CPU_FEATURE_CPA
    ARM: Instruction-only Checked Pointer Arithmetic

CPU_FEATURE_CPA2
    ARM: Checked Pointer Arithmetic

CPU_FEATURE_E2H0
    ARM: Programming of HCR_EL2.E2H.

CPU_FEATURE_E3DSE
    ARM: Delegated SError exception injection

CPU_FEATURE_ETS3
    ARM: Enhanced Translation Synchronization

CPU_FEATURE_FAMINMAX
    ARM: Floating-point maximum and minimum absolute value instructions

CPU_FEATURE_FGWTE3
    ARM: Fine-Grained Write Trap EL3

CPU_FEATURE_FP8
    ARM: FP8 convert instructions

CPU_FEATURE_FP8DOT2
    ARM: FP8 2-way dot product to half-precision instructions

CPU_FEATURE_FP8DOT4
    ARM: FP8 4-way dot product to single-precision instructions

CPU_FEATURE_FP8FMA
    ARM: FP8 multiply-accumulate to half-precision and single-precision instructions

CPU_FEATURE_FPMR
    ARM: Floating-point Mode Register

CPU_FEATURE_HACDBS
    ARM: Hardware accelerator for cleaning Dirty state

CPU_FEATURE_HDBSS
    ARM: Hardware Dirty state tracking structure

CPU_FEATURE_LUT
    ARM: Lookup table instructions with 2-bit and 4-bit indices

CPU_FEATURE_PAUTH_LR
    ARM: Pointer authentication instructions that allow signing of LR using SP and PC as diversifiers

CPU_FEATURE_RME_GPC2
    ARM: RME Granule Protection Check 2 Extension

CPU_FEATURE_SME_F8F16
    ARM: SME2 ZA-targeting FP8 multiply-accumulate, dot product, and outer product to half-precision instructions

CPU_FEATURE_SME_F8F32
    ARM: SME2 ZA-targeting FP8 multiply-accumulate, dot product, and outer product to single-precision instructions

CPU_FEATURE_SME_LUTV2
    ARM: Lookup table instructions with 4-bit indices and 8-bit elements

CPU_FEATURE_SPMU2
    ARM: System Performance Monitors Extension version 2

CPU_FEATURE_SSVE_FP8DOT2
    ARM: SVE FP8 2-way dot product to half-precision instructions in Streaming SVE mode

CPU_FEATURE_SSVE_FP8DOT4
    ARM: SVE2 FP8 4-way dot product to single-precision instructions in Streaming SVE mode

CPU_FEATURE_SSVE_FP8FMA
    ARM: SVE2 FP8 multiply-accumulate to half-precision and single-precision instructions in Streaming SVE mode

CPU_FEATURE_STEP2
    ARM: Enhanced Software Step Extension

CPU_FEATURE_TLBIW
    ARM: TLBI VMALL for Dirty state

  enum cpu_hint_t

CPU detection hints identifiers. Usage: similar to the flags usage

Enumerator

CPU_HINT_SSE_SIZE_AUTH
    SSE unit size is authoritative (not only a Family/Model guesswork, but based on an actual CPUID bit)

  enum cpu_msrinfo_request_t

Enumerator

INFO_MPERF
    Maximum performance frequency clock. This is a counter, which increments as a proportion of the actual processor speed.

INFO_APERF
    Actual performance frequency clock. This accumulates the core clock counts when the core is active.

INFO_MIN_MULTIPLIER
    Minimum CPU:FSB ratio for this CPU, multiplied by 100.

INFO_CUR_MULTIPLIER
    Current CPU:FSB ratio, multiplied by 100. e.g., a CPU:FSB value of 18.5 reads as '1850'.

INFO_MAX_MULTIPLIER
    Maximum CPU:FSB ratio for this CPU, multiplied by 100.

INFO_TEMPERATURE
    The current core temperature in Celsius.

INFO_THROTTLING
    1 if the current logical processor is throttling. 0 if it is running normally.

INFO_VOLTAGE
    The current core voltage in Volt, multiplied by 100.

INFO_BCLK
    See INFO_BUS_CLOCK.

INFO_BUS_CLOCK
    The main bus clock in MHz, e.g., FSB/QPI/DMI/HT base clock, multiplied by 100.

  enum cpu_purpose_t

CPU purpose.

Enumerator

PURPOSE_GENERAL
    general purpose CPU

PURPOSE_PERFORMANCE
    performance CPU

PURPOSE_EFFICIENCY
    efficiency CPU

PURPOSE_LP_EFFICIENCY
    low-power efficiency CPU

PURPOSE_U_PERFORMANCE
    ultimate performance CPU

NUM_CPU_PURPOSES
    Valid CPU purpose ids: 0..NUM_CPU_PURPOSES - 1

  enum cpu_sgx_feature_t

SGX features flags.

See also
    cpu_sgx_t

Usage:

...
struct cpu_raw_data_t raw;
struct cpu_id_t id;
if (cpuid_get_raw_data(&raw) == 0 && cpu_identify(&raw, &id) == 0 && id.sgx.present) {
    if (id.sgx.flags[INTEL_SGX1])
        // The CPU has SGX1 instructions support...
        ...
    } else {
        // no SGX
    }
} else {
  // processor cannot be determined.
}

Enumerator

INTEL_SGX1
    SGX1 instructions support

INTEL_SGX2
    SGX2 instructions support

  enum cpu_vendor_t

CPU vendor, as guessed from the Vendor String.

Enumerator

VENDOR_INTEL
    Intel CPU

VENDOR_AMD
    AMD CPU

VENDOR_CYRIX
    Cyrix CPU

VENDOR_NEXGEN
    NexGen CPU

VENDOR_TRANSMETA
    Transmeta CPU

VENDOR_UMC
    x86 CPU by UMC

VENDOR_CENTAUR
    x86 CPU by IDT

VENDOR_RISE
    x86 CPU by Rise Technology

VENDOR_SIS
    x86 CPU by SiS

VENDOR_NSC
    x86 CPU by National Semiconductor

VENDOR_HYGON
    Hygon CPU

VENDOR_ARM
    ARM CPU

VENDOR_BROADCOM
    Broadcom Corporation CPU

VENDOR_CAVIUM
    Cavium Inc. CPU

VENDOR_DEC
    Digital Equipment Corporation CPU

VENDOR_FUJITSU
    Fujitsu Ltd. CPU

VENDOR_HISILICON
    HiSilicon Technology Co., Ltd. CPU

VENDOR_INFINEON
    Infineon Technologies AG CPU

VENDOR_FREESCALE
    Motorola or Freescale Semiconductor Inc. CPU

VENDOR_NVIDIA
    NVIDIA Corporation CPU

VENDOR_APM
    Applied Micro Circuits Corporation CPU

VENDOR_QUALCOMM
    Qualcomm Inc. CPU

VENDOR_SAMSUNG
    Samsung Group CPU

VENDOR_MARVELL
    Marvell International Ltd. CPU

VENDOR_APPLE
    Apple Inc. CPU

VENDOR_FARADAY
    Faraday Technology CPU

VENDOR_MICROSOFT
    Microsoft Corporation CPU

VENDOR_PHYTIUM
    Phytium Technology Co., Ltd CPU

VENDOR_AMPERE
    Ampere Computing CPU

NUM_CPU_VENDORS
    Valid CPU vendor ids: 0..NUM_CPU_VENDORS - 1

  enum hypervisor_vendor_t

Hypervisor vendor, as guessed from the CPU_FEATURE_HYPERVISOR flag.

Enumerator

HYPERVISOR_NONE
    no hypervisor

HYPERVISOR_BHYVE
    FreeBSD bhyve hypervisor

HYPERVISOR_HYPERV
    Microsoft Hyper-V or Windows Virtual PC hypervisor

HYPERVISOR_KVM
    KVM hypervisor

HYPERVISOR_PARALLELS
    Parallels hypervisor

HYPERVISOR_QEMU
    QEMU hypervisor

HYPERVISOR_VIRTUALBOX
    VirtualBox hypervisor

HYPERVISOR_VMWARE
    VMware hypervisor

HYPERVISOR_XEN
    Xen hypervisor

NUM_HYPERVISOR_VENDORS
    Valid hypervisor vendor ids: 0..NUM_HYPERVISOR_VENDORS - 1

Function Documentation

  char * affinity_mask_str (cpu_affinity_mask_t * affinity_mask)

Returns textual representation of a CPU affinity mask.

Parameters
    affinity_mask - the affinity mask (in hexadecimal), whose textual representation is wanted.

Note
    This function is not thread-safe

Returns
    a string like '0000FFFF', '00FF0000', etc.

  char * affinity_mask_str_r (cpu_affinity_mask_t * affinity_mask, char * buffer, uint32_t buffer_len)

Returns textual representation of a CPU affinity mask (thread-safe)

Parameters
    affinity_mask - Input - the affinity mask (in hexadecimal), whose textual representation is wanted.
    buffer - Output - an allocated string where to store the textual representation, like '0000FFFF', '00FF0000', etc.
    buffer_len - Input - the size of buffer.

Returns
    a pointer on buffer

  const char * cpu_architecture_str (cpu_architecture_t architecture)

Returns the short textual representation of a CPU architecture.

Parameters
    architecture - the architecture, whose textual representation is wanted.

Returns
    a constant string like 'x86', 'ARM', etc.

  int cpu_clock (void)

Get the CPU clock frequency (all-in-one method) This is an all-in-one method for getting the CPU clock frequency. It tries to use the OS for that. If the OS doesn't have this info, it uses cpu_clock_measure with 200ms time interval and quadruple checking.

Returns
    the CPU clock frequency in MHz. If every possible method fails, the result is -1.

  int cpu_clock_by_ic (int millis, int runs)

Measure the CPU clock frequency using instruction-counting.

Parameters
    millis - how much time to allocate for each run, in milliseconds
    runs - how many runs to perform

The function performs a busy-wait cycle using a known number of 'heavy' (SSE) instructions. These instructions run at (more or less guaranteed) 1 IPC rate, so by running a busy loop for a fixed amount of time, and measuring the amount of instructions done, the CPU clock is accurately measured.

Of course, this function is still affected by the power-saving schemes, so the warnings as of cpu_clock_measure() still apply. However, this function is immune to problems with detection, related to the Intel Nehalem's 'Turbo' mode, where the internal clock is raised, but the RDTSC rate is unaffected.

The function will run for about (millis * runs) milliseconds. You can make only a single busy-wait run (runs == 1); however, this can be affected by task scheduling (which will break the counting), so allowing more than one run is recommended. As run length is not imperative for accurate readings (e.g., 50ms is sufficient), you can afford a lot of short runs, e.g. 10 runs of 50ms or 20 runs of 25ms.

Recommended values - millis = 50, runs = 4. For more robustness, increase the number of runs.

NOTE: on Bulldozer and later CPUs, the busy-wait cycle runs at 1.4 IPC, thus the results are skewed. This is corrected internally by dividing the resulting value by 1.4. However, this only occurs if the thread is executed on a single CMT module - if there are other threads competing for resources, the results are unpredictable. Make sure you run cpu_clock_by_ic() on a CPU that is free from competing threads, or if there are such threads, they shouldn't exceed the number of modules. On a Bulldozer X8, that means 4 threads.

Returns
    the CPU clock frequency in MHz (within some measurement error margin). If SSE is not supported, the result is -1. If the input parameters are incorrect, or some other internal fault is detected, the result is -2.

  int cpu_clock_by_mark (struct cpu_mark_t * mark)

Calculates the CPU clock.

Parameters
    mark - pointer to a cpu_mark_t structure, which has been initialized with cpu_tsc_mark and later `stopped' with cpu_tsc_unmark.

Note
    For reliable results, the marked time interval should be at least about 10 ms.

Returns
    the CPU clock frequency, in MHz. Due to measurement error, it will differ from the true value in a few least-significant bits. Accuracy depends on the timing interval - the more, the better. If the timing interval is insufficient, the result is -1. Also, see the comment on cpu_clock_measure for additional issues and pitfalls in using RDTSC for CPU frequency measurements.

  int cpu_clock_by_os (void)

Returns the CPU clock, as reported by the OS. This function uses OS-specific functions to obtain the CPU clock. It may differ from the true clock for several reasons:

i) The CPU might be in some power saving state, while the OS reports its full-power frequency, or vice-versa.
 ii) In some cases you can raise or lower the CPU frequency with overclocking utilities and the OS will not notice.

Returns
    the CPU clock frequency in MHz. If the OS is not (yet) supported or lacks the necessary reporting machinery, the return value is -1

  int cpu_clock_by_tsc (struct cpu_raw_data_t * raw)

Measure the CPU clock frequency using TSC frequency from CPUID.

Parameters
    raw - Optional input - a pointer to the raw CPUID data, which is obtained either by cpuid_get_raw_data or cpuid_deserialize_raw_data. Can also be NULL, in which case the functions calls cpuid_get_raw_data itself.

The function read Time Stamp Counter and Nominal Core Crystal Clock Information Leaf from CPUID. It determines the processor base frequency.

NOTE: only x86 Intel CPUs since Skylake (6th generation of Intel Core processors) are supported. Other vendors do not support this feature.

Returns
    the CPU clock frequency in MHz. If TSC frequency is not supported, the result is -1. If the input parameters are incorrect, or some other internal fault is detected, the result is -2.

  int cpu_clock_measure (int millis, int quad_check)

Measure the CPU clock frequency.

Parameters
    millis - How much time to waste in the busy-wait cycle. In millisecs. Useful values 10 - 1000
    quad_check - Do a more thorough measurement if nonzero (see the explanation).

The function performs a busy-wait cycle for the given time and calculates the CPU frequency by the difference of the TSC values. The accuracy of the calculation depends on the length of the busy-wait cycle: more is better, but 100ms should be enough for most purposes.

While this will calculate the CPU frequency correctly in most cases, there are several reasons why it might be incorrect:

i) RDTSC doesn't guarantee it will run at the same clock as the CPU. Apparently there aren't CPUs at the moment, but still, there's no guarantee.
 ii) The CPU might be in a low-frequency power saving mode, and the CPU might be switched to higher frequency at any time. If this happens during the measurement, the result can be anywhere between the low and high frequencies. Also, if you're interested in the high frequency value only, this function might return the low one instead.
 iii) On SMP systems exhibiting TSC drift (see cpu_rdtsc)

the quad_check option will run four consecutive measurements and then return the average of the two most-consistent results. The total runtime of the function will still be `millis' - consider using a bit more time for the timing interval.

Finally, for benchmarking / CPU intensive applications, the best strategy is to use the cpu_tsc_mark() / cpu_tsc_unmark() / cpu_clock_by_mark() method. Begin by mark()-ing about one second after application startup (allowing the power-saving manager to kick in and rise the frequency during that time), then unmark() just before application finishing. The result will most acurately represent at what frequency your app was running.

Returns
    the CPU clock frequency in MHz (within some measurement error margin). If RDTSC is not supported, the result is -1.

  void cpu_exec_cpuid (uint32_t eax, uint32_t * regs)

Executes the CPUID instruction.

Parameters
    eax - the value of the EAX register when executing CPUID
    regs - the results will be stored here. regs[0] = EAX, regs[1] = EBX, ...

Note
    CPUID will be executed with EAX set to the given value and EBX, ECX, EDX set to zero.

  void cpu_exec_cpuid_ext (uint32_t * regs)

Executes the CPUID instruction with the given input registers.

Note
    This is just a bit more generic version of cpu_exec_cpuid - it allows you to control all the registers.

Parameters
    regs - Input/output. Prior to executing CPUID, EAX, EBX, ECX and EDX will be set to regs[0], regs[1], regs[2] and regs[3]. After CPUID, this array will contain the results.

  const char * cpu_feature_level_str (cpu_feature_level_t level)

Returns the short textual representation of a CPU feature level.

Parameters
    level - the feature level, whose textual representation is wanted.

Returns
    a constant string like 'ARMv8.0-A', 'ARMv9.4-A', etc.

  const char * cpu_feature_str (cpu_feature_t feature)

Returns the short textual representation of a CPU flag.

Parameters
    feature - the feature, whose textual representation is wanted.

Returns
    a constant string like 'fpu', 'tsc', 'sse2', etc.

Note
    the names of the returned flags are compatible with those from /proc/cpuinfo in Linux, with the exception of `tm_amd'

  int cpu_identify (struct cpu_raw_data_t * raw, struct cpu_id_t * data)

Identifies the CPU.

Parameters
    raw - Input - a pointer to the raw CPUID data, which is obtained either by cpuid_get_raw_data or cpuid_deserialize_raw_data. Can also be NULL, in which case the functions calls cpuid_get_raw_data itself.
    data - Output - the decoded CPU features/info is written here.

Note
    The function will not fail, even if some of the information cannot be obtained. Even when the CPU is new and thus unknown to libcpuid, some generic info, such as 'AMD K9 family CPU' will be written to data.cpu_codename, and most other things, such as the CPU flags, cache sizes, etc. should be detected correctly anyway. However, the function CAN fail, if the CPU is completely alien to libcpuid.

    While cpu_identify() and cpuid_get_raw_data() are fast for most purposes, running them several thousand times per second can hamper performance significantly. Specifically, avoid writing 'cpu feature
          checker' wrapping function, which calls cpu_identify and returns the value of some flag, if that function is going to be called frequently.

Returns
    zero if successful, and some negative number on error. The error message can be obtained by calling cpuid_error.

See also
    cpu_error_t

  int cpu_identify_all (struct cpu_raw_data_array_t * raw_array, struct system_id_t * system)

Identifies all the CPUs.

Parameters
    raw_array - Input - a pointer to the array of raw CPUID data, which is obtained either by cpuid_get_all_raw_data or cpuid_deserialize_all_raw_data. Can also be NULL, in which case the functions calls cpuid_get_all_raw_data itself.
    system - Output - the decoded CPU features/info is written here for each CPU type.

Note
    The function is similar to cpu_identify. Refer to cpu_identify notes.

    As the memory is dynamically allocated, be sure to call cpuid_free_raw_data_array() and cpuid_free_system_id() after you're done with the data

Returns
    zero if successful, and some negative number on error. The error message can be obtained by calling cpuid_error.

See also
    cpu_error_t

  int cpu_msr_driver_close (struct msr_driver_t * handle)

Closes an open MSR driver. This function unloads the MSR driver opened by cpu_msr_driver_open and frees any resources associated with it.

Parameters
    handle - a handle to the MSR reader driver, as created by cpu_msr_driver_open

Returns
    zero if successful, and some negative number on error. The error message can be obtained by calling cpuid_error.

See also
    cpu_error_t

  struct msr_driver_t * cpu_msr_driver_open (void)

Starts/opens a driver, needed to read MSRs (Model Specific Registers) On systems that support it, this function will create a temporary system driver, that has privileges to execute the RDMSR instruction. After the driver is created, you can read MSRs by calling cpu_rdmsr

Returns
    a handle to the driver on success, and NULL on error. The error message can be obtained by calling cpuid_error.

See also
    cpu_error_t

  struct msr_driver_t * cpu_msr_driver_open_core (unsigned core_num)

Similar to cpu_msr_driver_open, but accept one parameter. This function works on certain operating systems (GNU/Linux, FreeBSD)

Parameters
    core_num specify the core number for MSR. The first core number is 0. The last core number is cpuid_get_total_cpus - 1.

Returns
    a handle to the driver on success, and NULL on error. The error message can be obtained by calling cpuid_error.

See also
    cpu_error_t

  int cpu_msrinfo (struct msr_driver_t * handle, cpu_msrinfo_request_t which)

Reads extended CPU information from Model-Specific Registers.

Parameters
    handle - a handle to an open MSR driver,

See also
    cpu_msr_driver_open

Parameters
    which - which info field should be returned. A list of available information entities is listed in the cpu_msrinfo_request_t enum.

Return values
    - if the requested information is available for the current processor model, the respective value is returned. if no information is available, or the CPU doesn't support the query, the special value CPU_INVALID_VALUE is returned

Note
    This function is not MT-safe. If you intend to call it from multiple threads, guard it through a mutex or a similar primitive.

  const char * cpu_purpose_str (cpu_purpose_t purpose)

Returns the short textual representation of a CPU purpose.

Parameters
    purpose - the purpose, whose textual representation is wanted.

Returns
    a constant string like 'general', 'performance', 'efficiency', etc.

  int cpu_rdmsr (struct msr_driver_t * handle, uint32_t msr_index, uint64_t * result)

Reads a Model-Specific Register (MSR) If the CPU has MSRs (as indicated by the CPU_FEATURE_MSR flag), you can read a MSR with the given index by calling this function.

There are several prerequisites you must do before reading MSRs: 1) You must ensure the CPU has RDMSR. Check the CPU_FEATURE_MSR flag in cpu_id_t::flags 2) You must ensure that the CPU implements the specific MSR you intend to read. 3) You must open a MSR-reader driver. RDMSR is a privileged instruction and needs ring-0 access in order to work. This temporary driver is created by calling cpu_msr_driver_open

Parameters
    handle - a handle to the MSR reader driver, as created by cpu_msr_driver_open
    msr_index - the numeric ID of the MSR you want to read
    result - a pointer to a 64-bit integer, where the MSR value is stored

Returns
    zero if successful, and some negative number on error. The error message can be obtained by calling cpuid_error.

See also
    cpu_error_t

  int cpu_rdmsr_range (struct msr_driver_t * handle, uint32_t msr_index, uint8_t highbit, uint8_t lowbit, uint64_t * result)

Similar to cpu_rdmsr, but extract a range of bits.

Parameters
    handle - a handle to the MSR reader driver, as created by cpu_msr_driver_open
    msr_index - the numeric ID of the MSR you want to read
    highbit - the high bit in range, must be inferior to 64
    lowbit - the low bit in range, must be equal or superior to 0
    result - a pointer to a 64-bit integer, where the MSR value is stored

Returns
    zero if successful, and some negative number on error. The error message can be obtained by calling cpuid_error.

See also
    cpu_error_t

  void cpu_rdtsc (uint64_t * result)

Executes RDTSC. The RDTSC (ReaD Time Stamp Counter) instruction gives access to an internal 64-bit counter, which usually increments at each clock cycle. This can be used for various timing routines, and as a very precise clock source. It is set to zero on system startup. Beware that may not increment at the same frequency as the CPU. Consecutive calls of RDTSC are, however, guaranteed to return monotonically-increasing values.

Parameters
    result - a pointer to a 64-bit unsigned integer, where the TSC value will be stored

Note
    If 100% compatibility is a concern, you must first check if the RDTSC instruction is present (if it is not, your program will crash with 'invalid opcode' exception). Only some very old processors (i486, early AMD K5 and some Cyrix CPUs) lack that instruction - they should have become exceedingly rare these days. To verify RDTSC presence, run cpu_identify() and check flags[CPU_FEATURE_TSC].

    The monotonically increasing nature of the TSC may be violated on SMP systems, if their TSC clocks run at different rate. If the OS doesn't account for that, the TSC drift may become arbitrary large.

  int cpu_request_core_type (cpu_purpose_t purpose, struct cpu_raw_data_array_t * raw_array, struct cpu_id_t * data)

Identifies a given CPU type.

Parameters
    purpose - Input - a cpu_purpose_t to request
    raw_array - Optional input - a pointer to the array of raw CPUID data, which is obtained either by cpuid_get_all_raw_data or cpuid_deserialize_all_raw_data. Can also be NULL, in which case the functions calls cpuid_get_all_raw_data itself.
    data - Output - the decoded CPU features/info is written here.

Returns
    zero if successful, and some negative number on error (like ERR_NOT_FOUND if CPU type not found). The error message can be obtained by calling cpuid_error.

See also
    cpu_error_t

  void cpu_tsc_mark (struct cpu_mark_t * mark)

Store TSC and timing info. This function stores the current TSC value and current time info from a precise OS-specific clock source in the cpu_mark_t structure. The sys_clock field contains time with microsecond resolution. The values can later be used to measure time intervals, number of clocks, FPU frequency, etc.

See also
    cpu_rdtsc

Parameters
    mark [out] - a pointer to a cpu_mark_t structure

  void cpu_tsc_unmark (struct cpu_mark_t * mark)

Calculate TSC and timing difference.

Parameters
    mark - input/output: a pointer to a cpu_mark_t structure, which has already been initialized by cpu_tsc_mark. The difference in TSC and time will be written here.

This function calculates the TSC and time difference, by obtaining the current TSC and timing values and subtracting the contents of the `mark' structure from them. Results are written in the same structure.

Example:

...
struct cpu_mark_t mark;
cpu_tsc_mark(&mark);
foo();
cpu_tsc_unmark(&mark);
printf("Foo finished. Executed in %llu cycles and %llu usecs\n",
       mark.tsc, mark.sys_clock);
...

  int cpuid_deserialize_all_raw_data (struct cpu_raw_data_array_t * data, const char * filename)

Reads all raw CPUID data from file.

Parameters
    data - a pointer to cpu_raw_data_array_t structure. The deserialized array data will be written here.
    filename - the path of the file, containing the serialized raw data. If empty, stdin will be used.

Note
    This function may fail, if the file is created by different version of the library. Also, see the notes on cpuid_serialize_all_raw_data.

    As the memory is dynamically allocated, be sure to call cpuid_free_raw_data_array() after you're done with the data

Returns
    zero if successful, and some negative number on error. The error message can be obtained by calling cpuid_error.

See also
    cpu_error_t

  int cpuid_deserialize_raw_data (struct cpu_raw_data_t * data, const char * filename)

Reads raw CPUID data from file.

Parameters
    data - a pointer to cpu_raw_data_t structure. The deserialized data will be written here.
    filename - the path of the file, containing the serialized raw data. If empty, stdin will be used.

Note
    This function may fail, if the file is created by different version of the library. Also, see the notes on cpuid_serialize_raw_data.

Returns
    zero if successful, and some negative number on error. The error message can be obtained by calling cpuid_error.

See also
    cpu_error_t

  const char * cpuid_error (void)

Returns textual description of the last error. libcpuid stores an `errno'-style error status, whose description can be obtained with this function.

Note
    This function is not thread-safe

See also
    cpu_error_t

  void cpuid_free_cpu_list (struct cpu_list_t * list)

Frees a CPU list. This function deletes all the memory associated with a CPU list, as obtained by cpuid_get_cpu_list()

Parameters
    list - the list to be free()'d.

  void cpuid_free_raw_data_array (struct cpu_raw_data_array_t * raw_array)

Frees a raw array. This function deletes all the memory associated with a raw array, as obtained by cpuid_get_all_raw_data(), cpuid_deserialize_all_raw_data() and cpu_identify_all()

Parameters
    raw_array - the raw array to be free()'d.

  void cpuid_free_system_id (struct system_id_t * system)

Frees a system ID type. This function deletes all the memory associated with a system ID, as obtained by cpu_identify_all()

Parameters
    system - the system ID to be free()'d.

  int cpuid_get_all_raw_data (struct cpu_raw_data_array_t * data)

Obtains the raw CPUID data from all CPUs.

Parameters
    data - a pointer to cpu_raw_data_array_t structure

Note
    As the memory is dynamically allocated, be sure to call cpuid_free_raw_data_array() after you're done with the data

Returns
    zero if successful, and some negative number on error. The error message can be obtained by calling cpuid_error.

See also
    cpu_error_t

  void cpuid_get_cpu_list (cpu_vendor_t vendor, struct cpu_list_t * list)

Gets a list of all known CPU names from a specific vendor. This function compiles a list of all known CPU (code)names (i.e. the possible values of cpu_id_t::cpu_codename) for the given vendor.

There are about 100 entries for Intel and AMD, and a few for the other vendors. The list is written out in approximate chronological introduction order of the parts.

Parameters
    vendor the vendor to be queried
    list [out] the resulting list will be written here. On failure, num_entries is set to zero and names to NULL. The error message can be obtained by calling cpuid_error.

See also
    cpu_error_t NOTE: As the memory is dynamically allocated, be sure to call cpuid_free_cpu_list() after you're done with the data

    cpu_list_t

  struct cpu_epc_t cpuid_get_epc (int index, const struct cpu_raw_data_t * raw)

Fetches information about an EPC (Enclave Page Cache) area.

Parameters
    index - zero-based index, valid range [0..cpu_id_t.egx.num_epc_sections)
    raw - a pointer to fetched raw CPUID data. Needed only for testing, you can safely pass NULL here (if you pass a real structure, it will be used for fetching the leaf 12h data if index < 2; otherwise the real CPUID instruction will be used).

Returns
    the requested data. If the CPU doesn't support SGX, or if index >= cpu_id_t.egx.num_epc_sections, both fields of the returned structure will be zeros.

  hypervisor_vendor_t cpuid_get_hypervisor (struct cpu_raw_data_t * raw, struct cpu_id_t * data)

Obtains the hypervisor vendor from CPUID from the current CPU.

Parameters
    raw - Optional input - a pointer to the raw CPUID data, which is obtained either by cpuid_get_raw_data or cpuid_deserialize_raw_data. Can also be NULL, in which case the functions calls cpuid_get_raw_data itself.
    data - Optional input - the decoded CPU features/info is written here. Can also be NULL, in which case the functions calls cpu_identify itself.

Note
    If no hypervisor is detected, the hypervisor can be hidden in some cases. Refer to https://github.com/anrieff/libcpuid/issues/90#issuecomment-296568713.

Returns
    HYPERVISOR_UNKNOWN if failed, HYPERVISOR_NONE if no hypervisor detected (or hidden), otherwise the hypervisor vendor type.

See also
    hypervisor_vendor_t

  int cpuid_get_raw_data (struct cpu_raw_data_t * data)

Obtains the raw CPUID data from the current CPU.

Parameters
    data - a pointer to cpu_raw_data_t structure

Returns
    zero if successful, and some negative number on error. The error message can be obtained by calling cpuid_error.

See also
    cpu_error_t

  int cpuid_get_raw_data_core (struct cpu_raw_data_t * data, logical_cpu_t logical_cpu)

Obtains the raw CPUID data from the specified CPU.

Parameters
    data - a pointer to cpu_raw_data_t structure
    logical_cpu specify the core number. The first core number is 0. The last core number is cpuid_get_total_cpus - 1.

Returns
    zero if successful, and some negative number on error. The error message can be obtained by calling cpuid_error.

See also
    cpu_error_t

  int cpuid_get_total_cpus (void)

Returns the total number of logical CPU threads (even if CPUID is not present). Under VM, this number (and total_logical_cpus, since they are fetched with the same code) may be nonsensical, i.e. might not equal NumPhysicalCPUs*NumCoresPerCPU*HyperThreading. This is because no matter how many logical threads the host machine has, you may limit them in the VM to any number you like. This is the number returned by cpuid_get_total_cpus().

Returns
    Number of logical CPU threads available. Equals the cpu_id_t::total_logical_cpus.

  cpu_vendor_t cpuid_get_vendor (void)

Obtains the CPU vendor from CPUID from the current CPU.

Note
    The result is cached.

Returns
    VENDOR_UNKNOWN if failed, otherwise the CPU vendor type.

See also
    cpu_vendor_t

  const char * cpuid_lib_version (void)

Returns the libcpuid version.

Returns
    the string representation of the libcpuid version, like '0.1.1'

  int cpuid_present (void)

Checks if the CPUID instruction is supported.

Return values
    1 if CPUID is present
    0 the CPU doesn't have CPUID.

  int cpuid_serialize_all_raw_data (struct cpu_raw_data_array_t * data, const char * filename)

Writes all the raw CPUID data to a text file.

Parameters
    data - a pointer to cpu_raw_data_array_t structure
    filename - the path of the file, where the serialized data for all CPUs should be written. If empty, stdout will be used.

Note
    This is intended primarily for debugging. On some processor, which is not currently supported or not completely recognized by cpu_identify_all, one can still successfully get the raw data and write it to a file. libcpuid developers can later import this file and debug the detection code as if running on the actual hardware. The file is simple text format of 'something=value' pairs. Version info is also written, but the format is not intended to be neither backward- nor forward compatible.

Returns
    zero if successful, and some negative number on error. The error message can be obtained by calling cpuid_error.

See also
    cpu_error_t

  int cpuid_serialize_raw_data (struct cpu_raw_data_t * data, const char * filename)

Writes the raw CPUID data to a text file.

Parameters
    data - a pointer to cpu_raw_data_t structure
    filename - the path of the file, where the serialized data should be written. If empty, stdout will be used.

Note
    This is intended primarily for debugging. On some processor, which is not currently supported or not completely recognized by cpu_identify, one can still successfully get the raw data and write it to a file. libcpuid developers can later import this file and debug the detection code as if running on the actual hardware. The file is simple text format of 'something=value' pairs. Version info is also written, but the format is not intended to be neither backward- nor forward compatible.

Returns
    zero if successful, and some negative number on error. The error message can be obtained by calling cpuid_error.

See also
    cpu_error_t

  void cpuid_set_verbosiness_level (int level)

Sets the verbosiness level. When the verbosiness level is above zero, some functions might print diagnostic information about what are they doing. The higher the level is, the more detail is printed. Level zero is guaranteed to omit all such output. The output is written using the same machinery as the warnings,

See also
    cpuid_set_warn_function()

Parameters
    level the desired verbosiness level. Useful values 0..2 inclusive

  libcpuid_warn_fn_t cpuid_set_warn_function (libcpuid_warn_fn_t warn_fun)

Sets the warning print function. In some cases, the internal libcpuid machinery would like to emit useful debug warnings. By default, these warnings are written to stderr. However, you can set a custom function that will receive those warnings.

Parameters
    warn_fun - the warning function you want to set. If NULL, warnings are disabled. The function takes const char* argument.

Returns
    the current warning function. You can use the return value to keep the previous warning function and restore it at your discretion.

  int msr_serialize_raw_data (struct msr_driver_t * handle, const char * filename)

Writes the raw MSR data to a text file.

Parameters
    handle - a handle to the MSR reader driver, as created by cpu_msr_driver_open
    filename - the path of the file, where the serialized data should be written. If empty, stdout will be used.

Note
    This is intended primarily for debugging. On some processor, which is not currently supported or not completely recognized by cpu_identify, one can still successfully get the raw data and write it to a file. libcpuid developers can later import this file and debug the detection code as if running on the actual hardware. The file is simple text format of 'something=value' pairs. Version info is also written, but the format is not intended to be neither backward- nor forward compatible.

Returns
    zero if successful, and some negative number on error. The error message can be obtained by calling cpuid_error.

See also
    cpu_error_t

Author

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