Re: [RFC][PATCH] Randomize kernel base address on boot

H. Peter Anvin
2011-05-31T18:40:58Z

On 05/31/2011 09:52 AM, Matthew Garrett wrote:
> On Thu, May 26, 2011 at 04:39:27PM -0400, Dan Rosenberg wrote:
>
>> 1. I'm nearly finished a first draft of code to parse the BIOS E820
>> memory map to determine where it's safe to place the randomized kernel.
>> This code accounts for overlapping regions, as well as potential
>> conflicts in region types (free vs. reserved, etc.), in favor of
>> non-free types. The end result is, I'll have a reasonable upper bound.
>
> The BIOS E820 map, or the kernel representation? In either case, this
> isn't going to work well with EFI. There are regions that will be marked
> as available in the E820 map that we *mustn't* touch until we've entered
> EFI virtual mode.
>
> (This is, clearly, insane).
>

I believe we could (should!) mark them reserved, not available, in the
E820 map and free them later.

-hpa