File Access In Kernel Modules?

gibson_81 asks: "I'm writing a device driver for a really ugly piece of hardware: it needs me to read in firmware from a file before I can initialize it. For now, I force the user-program to read the entire file into memory and pass that memory buffer as an IOCTL argument, but that's even uglier than the hardware. None of the documents on writing kernel device drivers have mentioned how to access files from the kernel, but some source-grepping led me to sys_open ... which was not exported to modules :( So, I ask you, the Slashdot community: do you know what functions I can use to do this, or is it a no-no?"