[LinuxBIOS] [PATCH] pci_rom.c checksum extension rom
alex at rtfs.hu
Wed Oct 3 01:48:38 CEST 2007
On Sat, 2007-09-29 at 23:49 +0200, Carl-Daniel Hailfinger wrote:
> On 12.09.2007 21:37, Alex Beregszaszi wrote:
> > Hi,
> > On Fri, 2007-09-07 at 12:54 +0200, Alex Beregszaszi wrote:
> >> Hi,
> >> On Wed, 2007-09-05 at 04:29 +0200, Stefan Reinauer wrote:
> >>> * Alex Beregszaszi <alex at rtfs.hu> [070904 13:17]:
> >>>> Hi,
> >>>> the attached patch adds code to checksum the pci extension rom and stop
> >>>> if the stored and calculated checksum differ.
> >>> Is this checksum reliably correct? I am hesitating to add new
> >>> restrictions that might break otherwise working cards.
> >> You are right, attached is a correct method. There is no fixed checksum
> >> byte, instead the whole should sum to zero.
> > Any comments on this?
> I like it. I'd give you an Ack, but I have no hardware to test with.
> Stefan? Ron?
> Worst case would be that buggy extension ROMs break with a really loud
> warning, so anybody with such ROMs will see it prominently in the logs.
> Alex: Is there an easy way to check extension ROMs in the current
> machine for correct signatures? Maybe standalone utility or such stuff.
There is no utility for that, but you could copy out the memory between
0xc0000 - 0xf00000 from /dev/mem and search for extension headers in it
(see the code in pci_rom.c).
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