Converting windows driver to 64 bit - can I use a 32-bit dll?

Question

My windows driver has a .sys file and a .dll (which I'm guessing is the programming interface to the driver?) Anyway, I need to compile the driver to run on Windows 7 64-bit. I have downloaded the WinDDK and am able to compile everything, but my application still won't work with the new driver. My question is - if the application is a 32-bit app, does the driver dll need to be compiled as a 32-bit dll, and the .sys file a 64-bit file? Or do the sys and dll file both need to be 64-bit?

Thanks.

Answer 1

You cannot execute 32-bit code in the 64-bit kernel.

The DLL also needs to be 64-bit.

Answer 2

The DLL has to be 64 bit too.

Will try to find a reference.

Got one

Since a 64-bit program can't call a 32-bit Dynamic Link Library (DLL)

This is why no 32 bit driver works on 64 bit and why they are always separate downloads