mmap equivalent in Windows or How To Map Physical Memory to Userspace.

Windows unfortunately has no equivalent of mmap that can access physical memory e.g by mapping /dev/mem to some userspace address, however this can be achieved by a simple(not really) kernel-mode driver that I've personally used in Windows 7 x64, though there should be no reason why it wouldn't work in Windows 8/8.1/10

I found it in this article on CodeProject.

Now, even if you compile the driver, on x64 Windows systems the driver needs to be signed, this for development purposes can be disabled, follow the article on MSDN on how to do that.

But beware, fiddling with physical memory can lead to some very dangerous results if you aren't careful, e.g permanent hardware failure or data loss.

Location of the ATI ATOMBIOS!

After having a chat with some guys developing the open source radeon driver on freenode, and with the reverse engineering of GPU-Z I found where the ATI ATOMBIOS is located.

Pretty simple actually, you take the BAR2(Base Address Register #2) and XOR it with 0x80000 afterwards you AND the result with 0xFFFE0000.

In practical terms

atombiosaddress = (BAR2 ^ 0x80000) & 0xFFFE0000.

Also, the VBIOS of the primary card can also be located at physical address 0xc0000 like radentool has specified.

EDIT: I did a binary comparison of my dump of my card vs the one from GPU-Z and mine seems to contain different data at certain locations. So not quite there yet.
Something interesting I discovered is that the location of the ATOMBIOS on the primary card is not always available at the address using the formula above, the address is valid, however the GPU-Z driver does something to make the card map the BIOS to that location, after it's done the address is valid, just doesn't contain anything. It works on non-primary cards though.