Re: Exposing ROM's though sysfs

Matthew Wilcox
2004-07-30T19:05:06Z

On Fri, Jul 30, 2004 at 11:59:21AM -0700, Jon Smirl wrote:
> Alan Cox knows more about this, but I believe there is only one PCI
> card in existence that does this.

Strange; he was the one who pointed out this requirement to me in the
first place and he hinted that many devices did this.

> For the one or two cards that do this, the device drivers could flag
> this to the PCI subsystem. In the flagged case the sysfs read code
> could shut off interrupts, enable the ROM, copy it, and then reenable
> interrupts.

Shutting off interrupts isn't nearly enough. Any other CPU could access the
device, or indeed any device capable of DMA could potentially cause trouble.

--
"Next the statesmen will invent cheap lies, putting the blame upon
the nation that is attacked, and every man will be glad of those
conscience-soothing falsities, and will diligently study them, and refuse
to examine any refutations of them; and thus he will by and by convince
himself that the war is just, and will thank God for the better sleep
he enjoys after this process of grotesque self-deception." -- Mark Twain