Re: [PATCH RFC] x86: check for and defend against BIOS memory corruption

Jeremy Fitzhardinge
2008-08-29T14:08:28Z

Hugh Dickins wrote:
> Not quite the output we were expecting! I've not got around to trying
> it yet, so beware, but I think Jeremy's patch needs the following on top.
> Or you may prefer to wait until one of us reports that it is now working
> as intended.
>
> --- a/arch/x86/kernel/setup.c 2008-08-29 11:17:16.000000000 +0100
> +++ b/arch/x86/kernel/setup.c 2008-08-29 11:19:24.000000000 +0100
> @@ -636,11 +636,12 @@ void check_for_bios_corruption(void)
> unsigned long *addr = __va(scan_areas[i].addr);
> unsigned long size = scan_areas[i].size;
>
> - for(; size; addr++, size--) {
> + for(; size; addr++, size -= sizeof(unsigned long)) {
>

Oops, yes.

> if (!*addr)
> continue;
> printk(KERN_ERR "Corrupted low memory at %p (%lx phys) = %08lx\n",
> addr, __pa(addr), *addr);
> + *addr = 0;
>

Good idea.

> corruption = 1;
> }
> }

J