DriverEntry is the first routine called after a driver is loaded, and is responsible for initializing the driver.
DriverEntry是驱动加载后第一个执行的例程，它负责初始化驱动程序。
语法：
DRIVER_INITIALIZE DriverEntry;
NTSTATUS DriverEntry(
_In_ struct _DRIVER_OBJECT *DriverObject,
_In_ PUNICODE_STRING RegistryPath
)
{ ... }
参数：
DriverObject [in]
A pointer to a DRIVER_OBJECT structure. This is the driver's driver object.
一个DRIVER_OBJECT结构体的指针，是驱动程序的驱动对象。
RegistryPath [in]
A pointer to a counted Unicode string specifying the path to the driver's registry key.
一个UNICODE字符串，指定驱动程序在注册表中对应的键值。
返回值：
If the routine succeeds, it must return STATUS_SUCCESS. Otherwise, it must return one of the error status values defined in Ntstatus.h.
如果执行成功，必须返回STATUS_SUCCESS, 其它情况下，返回ntstatus.h定义的错误码。
其它说明：
The DriverObject parameter supplies the DriverEntry routine with a pointer to the driver's driver object, which is allocated by the I/O manager.
DriverEntry程的DriverObject参数是一个由IO管理器分配的指向驱动程序的驱动对象指针。
The DriverEntry routine must fill in the driver object with entry points for the driver's standard routines.
DriverEntry必须指定驱动程序的标准例程的入口点。
The DriverObject pointer gives the driver access to DriverObject->HardwareDatabase,
驱动程序通过DriverObject->HardwareDatabase(一个UNICODE字符串)访问\Registry\Machine\Hardware子树。
which points to a counted Unicode string that specifies a path to the registry's \Registry\Machine\Hardware tree.
The registry path string pointed to by RegistryPath is of the form \Registry\Machine\System\CurrentControlSet\Services\DriverName.
RegistryPath是一个指向\Registry\Machine\System\CurrentControlSet\Services\DriverName注册表路径的UNICODE字符串，
A driver can use this path to store driver-specific information; see Registry Keys for Drivers.
驱动程序可以使用注册表保存一些驱动程序的配置信息。
The DriverEntry routine should save a copy of the Unicode string,
not the pointer, since the I/O manager frees the RegistryPath buffer after DriverEntry returns.
DriverEntry应该保存一个UNICODE字符串(如果以后会用到)，而不是指针，因为I/O管理器在它返回后会释放RegisterPath。
While it is possible to name this routine something other than DriverEntry, doing so is not recommended.
虽然这个入口函数可以使用其它的名字，但不推荐这么做。
The DDK-supplied build tools automatically inform the linker that the driver's entry point is called DriverEntry,
so giving the routine another name requires you to modify the build tools.
DDK提供的build工具默认使用DriverEntry这个入口函数进行链接，所以，使用其它的入口函数名称，需要你修改build工具的参数。