KUSER_SHARED_DATA - NtDoc
Native API online documentation, based on the System Informer
(formerly Process Hacker) phnt
headers
#ifndef _NTEXAPI_H
#if (PHNT_MODE != PHNT_MODE_KERNEL)
typedef struct _KUSER_SHARED_DATA
{
//
// Current low 32-bit of tick count and tick count multiplier.
//
// N.B. The tick count is updated each time the clock ticks.
//
ULONG TickCountLowDeprecated;
ULONG TickCountMultiplier;
//
// Current 64-bit interrupt time in 100ns units.
//
volatile KSYSTEM_TIME InterruptTime;
//
// Current 64-bit system time in 100ns units.
//
volatile KSYSTEM_TIME SystemTime;
//
// Current 64-bit time zone bias.
//
volatile KSYSTEM_TIME TimeZoneBias;
//
// Support image magic number range for the host system.
//
// N.B. This is an inclusive range.
//
USHORT ImageNumberLow;
USHORT ImageNumberHigh;
//
// Copy of system root in unicode.
//
// N.B. This field must be accessed via the RtlGetNtSystemRoot API for
// an accurate result.
//
WCHAR NtSystemRoot[260];
//
// Maximum stack trace depth if tracing enabled.
//
ULONG MaxStackTraceDepth;
//
// Crypto exponent value.
//
ULONG CryptoExponent;
//
// Time zone ID.
//
ULONG TimeZoneId;
ULONG LargePageMinimum;
//
// This value controls the AIT Sampling rate.
//
ULONG AitSamplingValue;
//
// This value controls switchback processing.
//
ULONG AppCompatFlag;
//
// Current Kernel Root RNG state seed version
//
ULONGLONG RNGSeedVersion;
//
// This value controls assertion failure handling.
//
ULONG GlobalValidationRunlevel;
volatile LONG TimeZoneBiasStamp;
//
// The shared collective build number undecorated with C or F.
// GetVersionEx hides the real number
//
ULONG NtBuildNumber;
//
// Product type.
//
// N.B. This field must be accessed via the RtlGetNtProductType API for
// an accurate result.
//
NT_PRODUCT_TYPE NtProductType;
BOOLEAN ProductTypeIsValid;
BOOLEAN Reserved0[1];
USHORT NativeProcessorArchitecture;
//
// The NT Version.
//
// N. B. Note that each process sees a version from its PEB, but if the
// process is running with an altered view of the system version,
// the following two fields are used to correctly identify the
// version
//
ULONG NtMajorVersion;
ULONG NtMinorVersion;
//
// Processor features.
//
BOOLEAN ProcessorFeatures[PROCESSOR_FEATURE_MAX];
//
// Reserved fields - do not use.
//
ULONG Reserved1;
ULONG Reserved3;
//
// Time slippage while in debugger.
//
volatile ULONG TimeSlip;
//
// Alternative system architecture, e.g., NEC PC98xx on x86.
//
ALTERNATIVE_ARCHITECTURE_TYPE AlternativeArchitecture;
//
// Boot sequence, incremented for each boot attempt by the OS loader.
//
ULONG BootId;
//
// If the system is an evaluation unit, the following field contains the
// date and time that the evaluation unit expires. A value of 0 indicates
// that there is no expiration. A non-zero value is the UTC absolute time
// that the system expires.
//
LARGE_INTEGER SystemExpirationDate;
//
// Suite support.
//
// N.B. This field must be accessed via the RtlGetSuiteMask API for
// an accurate result.
//
ULONG SuiteMask;
//
// TRUE if a kernel debugger is connected/enabled.
//
BOOLEAN KdDebuggerEnabled;
//
// Mitigation policies.
//
union
{
UCHAR MitigationPolicies;
struct
{
UCHAR NXSupportPolicy : 2;
UCHAR SEHValidationPolicy : 2;
UCHAR CurDirDevicesSkippedForDlls : 2;
UCHAR Reserved : 2;
};
};
//
// Measured duration of a single processor yield, in cycles. This is used by
// lock packages to determine how many times to spin waiting for a state
// change before blocking.
//
USHORT CyclesPerYield;
//
// Current console session Id. Always zero on non-TS systems.
//
// N.B. This field must be accessed via the RtlGetActiveConsoleId API for an
// accurate result.
//
volatile ULONG ActiveConsoleId;
//
// Force-dismounts cause handles to become invalid. Rather than always
// probe handles, a serial number of dismounts is maintained that clients
// can use to see if they need to probe handles.
//
volatile ULONG DismountCount;
//
// This field indicates the status of the 64-bit COM+ package on the
// system. It indicates whether the Intermediate Language (IL) COM+
// images need to use the 64-bit COM+ runtime or the 32-bit COM+ runtime.
//
ULONG ComPlusPackage;
//
// Time in tick count for system-wide last user input across all terminal
// sessions. For MP performance, it is not updated all the time (e.g. once
// a minute per session). It is used for idle detection.
//
ULONG LastSystemRITEventTickCount;
//
// Number of physical pages in the system. This can dynamically change as
// physical memory can be added or removed from a running system. This
// cell is too small to hold the non-truncated value on very large memory
// machines so code that needs the full value should access
// FullNumberOfPhysicalPages instead.
//
ULONG NumberOfPhysicalPages;
//
// True if the system was booted in safe boot mode.
//
BOOLEAN SafeBootMode;
//
// Virtualization flags.
//
union
{
UCHAR VirtualizationFlags;
#if defined(_ARM64_)
//
// N.B. Keep this bitfield in sync with the one in arc.w.
//
struct
{
UCHAR ArchStartedInEl2 : 1;
UCHAR QcSlIsSupported : 1;
UCHAR : 6;
};
#endif
};
//
// Reserved (available for reuse).
//
UCHAR Reserved12[2];
//
// This is a packed bitfield that contains various flags concerning
// the system state. They must be manipulated using interlocked
// operations.
//
// N.B. DbgMultiSessionSku must be accessed via the RtlIsMultiSessionSku
// API for an accurate result
//
union
{
ULONG SharedDataFlags;
struct
{
//
// The following bit fields are for the debugger only. Do not use.
// Use the bit definitions instead.
//
ULONG DbgErrorPortPresent : 1;
ULONG DbgElevationEnabled : 1;
ULONG DbgVirtEnabled : 1;
ULONG DbgInstallerDetectEnabled : 1;
ULONG DbgLkgEnabled : 1;
ULONG DbgDynProcessorEnabled : 1;
ULONG DbgConsoleBrokerEnabled : 1;
ULONG DbgSecureBootEnabled : 1;
ULONG DbgMultiSessionSku : 1;
ULONG DbgMultiUsersInSessionSku : 1;
ULONG DbgStateSeparationEnabled : 1;
ULONG DbgSplitTokenEnabled : 1;
ULONG DbgShadowAdminEnabled : 1;
ULONG SpareBits : 19;
} DUMMYSTRUCTNAME2;
} DUMMYUNIONNAME2;
ULONG DataFlagsPad[1];
//
// Depending on the processor, the code for fast system call will differ,
// Stub code is provided pointers below to access the appropriate code.
//
// N.B. The following field is only used on 32-bit systems.
//
ULONGLONG TestRetInstruction;
LONGLONG QpcFrequency;
//
// On AMD64, this value is initialized to a nonzero value if the system
// operates with an altered view of the system service call mechanism.
//
ULONG SystemCall;
//
// Reserved field - do not use. Used to be UserCetAvailableEnvironments.
//
ULONG Reserved2;
//
// Full 64 bit version of the number of physical pages in the system.
// This can dynamically change as physical memory can be added or removed
// from a running system.
//
ULONGLONG FullNumberOfPhysicalPages;
//
// Reserved, available for reuse.
//
ULONGLONG SystemCallPad[1];
//
// The 64-bit tick count.
//
union
{
volatile KSYSTEM_TIME TickCount;
volatile ULONG64 TickCountQuad;
struct
{
ULONG ReservedTickCountOverlay[3];
ULONG TickCountPad[1];
} DUMMYSTRUCTNAME;
} DUMMYUNIONNAME3;
//
// Cookie for encoding pointers system wide.
//
ULONG Cookie;
ULONG CookiePad[1];
//
// Client id of the process having the focus in the current
// active console session id.
//
// N.B. This field must be accessed via the
// RtlGetConsoleSessionForegroundProcessId API for an accurate result.
//
LONGLONG ConsoleSessionForegroundProcessId;
//
// N.B. The following data is used to implement the precise time
// services. It is aligned on a 64-byte cache-line boundary and
// arranged in the order of typical accesses.
//
// Placeholder for the (internal) time update lock.
//
ULONGLONG TimeUpdateLock;
//
// The performance counter value used to establish the current system time.
//
ULONGLONG BaselineSystemTimeQpc;
//
// The performance counter value used to compute the last interrupt time.
//
ULONGLONG BaselineInterruptTimeQpc;
//
// The scaled number of system time seconds represented by a single
// performance count (this value may vary to achieve time synchronization).
//
ULONGLONG QpcSystemTimeIncrement;
//
// The scaled number of interrupt time seconds represented by a single
// performance count (this value is constant after the system is booted).
//
ULONGLONG QpcInterruptTimeIncrement;
//
// The scaling shift count applied to the performance counter system time
// increment.
//
UCHAR QpcSystemTimeIncrementShift;
//
// The scaling shift count applied to the performance counter interrupt time
// increment.
//
UCHAR QpcInterruptTimeIncrementShift;
//
// The count of unparked processors.
//
USHORT UnparkedProcessorCount;
//
// A bitmask of enclave features supported on this system.
//
// N.B. This field must be accessed via the RtlIsEnclaveFeaturePresent API for an
// accurate result.
//
ULONG EnclaveFeatureMask[4];
//
// Current coverage round for telemetry based coverage.
//
ULONG TelemetryCoverageRound;
//
// The following field is used for ETW user mode global logging
// (UMGL).
//
USHORT UserModeGlobalLogger[16];
//
// Settings that can enable the use of Image File Execution Options
// from HKCU in addition to the original HKLM.
//
ULONG ImageFileExecutionOptions;
//
// Generation of the kernel structure holding system language information
//
ULONG LangGenerationCount;
//
// Reserved (available for reuse).
//
ULONGLONG Reserved4;
//
// Current 64-bit interrupt time bias in 100ns units.
//
volatile ULONGLONG InterruptTimeBias;
//
// Current 64-bit performance counter bias, in performance counter units
// before the shift is applied.
//
volatile ULONGLONG QpcBias;
//
// Number of active processors and groups.
//
ULONG ActiveProcessorCount;
volatile UCHAR ActiveGroupCount;
//
// Reserved (available for re-use).
//
UCHAR Reserved9;
union
{
USHORT QpcData;
struct
{
//
// A bitfield indicating whether performance counter queries can
// read the counter directly (bypassing the system call) and flags.
//
volatile UCHAR QpcBypassEnabled;
//
// Reserved, leave as zero for backward compatibility. Was shift
// applied to the raw counter value to derive QPC count.
//
UCHAR QpcReserved;
};
};
LARGE_INTEGER TimeZoneBiasEffectiveStart;
LARGE_INTEGER TimeZoneBiasEffectiveEnd;
//
// Extended processor state configuration (AMD64 and x86).
//
XSTATE_CONFIGURATION XState;
KSYSTEM_TIME FeatureConfigurationChangeStamp;
ULONG Spare;
ULONG64 UserPointerAuthMask;
//
// Extended processor state configuration (ARM64). The reserved space for
// other architectures is not available for reuse.
//
#if defined(_ARM64_)
XSTATE_CONFIGURATION XStateArm64;
#else
ULONG Reserved10[210];
#endif
} KUSER_SHARED_DATA, *PKUSER_SHARED_DATA;
View code on GitHubThis structure is documented in Windows Driver Kit.