派遣例程和 IRQLs

Dispatch Routines and IRQLs

Most drivers' dispatch routines are called in an arbitrary thread context at IRQL = PASSIVE_LEVEL, with the following exceptions:

• Any highest-level driver's dispatch routines are called in the context of the thread that originated the I/O request, which is commonly a user-mode application thread.

  In other words, the dispatch routines of file system drivers and other highest-level drivers are called in a nonarbitrary thread context at IRQL = PASSIVE_LEVEL.

• The DispatchRead, DispatchWrite, and DispatchDeviceControl routines of lowest-level device drivers, and of intermediate drivers layered above them in the system paging path, can be called at IRQL = APC_LEVEL and in an arbitrary thread context.

  The DispatchRead and/or DispatchWrite routines, and any other routine that also processes read and/or write requests in such a lowest-level device or intermediate driver, must be resident at all times. These driver routines can neither be pageable nor be part of a driver's pageable-image section; they must not access any pageable memory. Furthermore, they should not be dependent on any blocking calls (such as KeWaitForSingleObject with a nonzero time-out).

• The DispatchPower routine of drivers in the hibernation and/or paging paths can be called at IRQL = DISPATCH_LEVEL. The DispatchPnP routines of such drivers must be prepared to handle PnPIRP_MN_DEVICE_USAGE_NOTIFICATION requests.
• The DispatchPower routine of drivers that require inrush power at start-up can be called at IRQL = DISPATCH_LEVEL.

 

 

符号	格式说明符	类型
%c, %lc	ANSI字符	char
%C, %wc	宽字符	wchar_t
%d, %i	十进制有符号整数	int
%D	十进制__int64	__int64
%L	十六进制的LARGE_INTEGER	LARGE_INTEGER
%s, %ls	NULL终止的ANSI字符串	char*
%S, %ws	NULL终止的宽字符串	wchar_t*
%Z	ANSI_STRING字符串	PANSI_STRING
%wZ	UNICODE_STRING字符串	PUNICODE_STRING
%u	十进制的ULONG	ULONG
%x	小写字符十六进制的ULONG	ULONG
%X	大写字符十六进制的ULONG	ULONG
%p	指针Pointer 32/64位

根据DDK上说明,Unicode格式(%C, %S, %lc, %ls, %wc, %ws, and %wZ)只能在 IRQL = PASSIVE_LEVEL时才能使用。