lkml.org 
[lkml]   [2012]   [Oct]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] Fix devmem_is_allowed for below 1MB accesses for an efi machine
On Tue, Oct 02, 2012 at 02:50:09PM -0700, H. Peter Anvin wrote:

> That sounds like exactly the opposite of normal /dev/mem behavior... we
> allow access to non-memory resources (which really could do anything if
> misused), but not memory.

From arch/x86/mm/init.c:

* On x86, access has to be given to the first megabyte of ram because that area
* contains bios code and data regions used by X and dosemu and similar apps.

Limiting this to just RAM would be safer than it currently is. I'm not
convinced that there's any good reason to allow *any* access down there
for EFI systems, though.

--
Matthew Garrett | mjg59@srcf.ucam.org


\
 
 \ /
  Last update: 2012-10-03 07:01    [W:0.062 / U:0.468 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site