IRQL - Interrupt Request Level

//wdm.h #if defined(_X86_) // // Interrupt Request Level definitions // #define PASSIVE_LEVEL 0 // Passive release level #define LOW_LEVEL 0 // Lowest interrupt level #define APC_LEVEL 1 // APC interrupt level #define DISPATCH_LEVEL 2 // Dispatcher level #define CMCI_LEVEL 5 // CMCI handler level #define PROFILE_LEVEL 27 // timer used for profiling. #define CLOCK1_LEVEL 28 // Interval clock 1 level - Not used on x86 #define CLOCK2_LEVEL 28 // Interval clock 2 level #define IPI_LEVEL 29 // Interprocessor interrupt level #define POWER_LEVEL 30 // Power failure level #define HIGH_LEVEL 31 // Highest interrupt level #define CLOCK_LEVEL (CLOCK2_LEVEL) #endif #if defined(_AMD64_) // // Interrupt Request Level definitions // #define PASSIVE_LEVEL 0 // Passive release level #define LOW_LEVEL 0 // Lowest interrupt level #define APC_LEVEL 1 // APC interrupt level #define DISPATCH_LEVEL 2 // Dispatcher level #define CMCI_LEVEL 5 // CMCI handler level #define CLOCK_LEVEL 13 // Interval clock level #define IPI_LEVEL 14 // Interprocessor interrupt level #define DRS_LEVEL 14 // Deferred Recovery Service level #define POWER_LEVEL 14 // Power failure level #define PROFILE_LEVEL 15 // timer used for profiling. #define HIGH_LEVEL 15 // Highest interrupt level #endif #if defined(_IA64_) // // Define Interrupt Request Levels. // #define PASSIVE_LEVEL 0 // Passive release level #define LOW_LEVEL 0 // Lowest interrupt level #define APC_LEVEL 1 // APC interrupt level #define DISPATCH_LEVEL 2 // Dispatcher level #define CMC_LEVEL 3 // Correctable machine check level #define DEVICE_LEVEL_BASE 4 // 4 - 11 - Device IRQLs #define PC_LEVEL 12 // Performance Counter IRQL #define IPI_LEVEL 14 // IPI IRQL #define DRS_LEVEL 14 // Deferred Recovery Service level #define CLOCK_LEVEL 13 // Clock Timer IRQL #define POWER_LEVEL 15 // Power failure level #define PROFILE_LEVEL 15 // Profiling level #define HIGH_LEVEL 15 // Highest interrupt level #endif #define LOW_PRIORITY 0 // Lowest thread priority level #define LOW_REALTIME_PRIORITY 16 // Lowest realtime priority level #define HIGH_PRIORITY 31 // Highest thread priority level #define MAXIMUM_PRIORITY 32 // Number of thread priority levels #define MAXIMUM_WAIT_OBJECTS 64 // Maximum number of wait objects #define MAXIMUM_SUSPEND_COUNT MAXCHAR // Maximum times thread can be suspended

NTSTATUS KeWaitForSingleObject ( PVOID Object, KWAIT_REASON WaitReason, KPROCESSOR_MODE WaitMode, BOOLEAN Alertable, PLARGE_INTEGER Timeout );