Messages in this thread |  | | | Date | Fri, 21 Mar 2008 14:24:17 +0100 | | From | Ingo Molnar <> | | Subject | Re: [patch 00/13] x86: PAT support updated - v3 |
| |
* venkatesh.pallipadi@intel.com <venkatesh.pallipadi@intel.com> wrote:
> Follow up on earlier PAT patch series here: > http://lkml.org/lkml/2008/1/10/312 > > This patch series adds Page Attribute Table (PAT) support on x86. > There have been few changes based on comments for earlier patches and > also issues that was seen while the earlier patchset was in mm. The > main changes include: > > * Unlike earlier patchset, there are no changes to identity mapping of > reserved regions. > * Unlike earlier patches, there are no chanegs to early ioremap. > * We look at MTRR setting and PAT request and track the resultant type > to avoid aliasing. > * UC_MINUS in PAT to provide backward compatibility to /dem/mem mmap users. > > In general, we have tried to make patches more simpler and cleaner. > Hope is to cause less disruption along the way. The changes/cleaups > that went into x86/mm (specifically pageattr.c) has helped us along > the way. > > The patchset is against x86 testing from couple of days back.
thanks Venki, i've queued this up so that we can see how well it goes. It now looks a lot less dangerous and more compatible than it did before - but i'm sure there'll be issues nevertheless :-/
> There are two issues that we are leaving out at the moment to make the patch > simple. We will be addressing them with incremental patches soon: > * FB/DRM drivers using pgprot_val and changing protection on their own > without using any proper APIs like ioremap. There are few such usages and > each one will be addressed separately. > * To change attributes from WC to WB in a "perfect way", one has to follow > certain sequence like make page non-present etc.
hm, until this is done correctly i guess we should disallow WC to WB transitions? A good number of erratas apply i suspect :-/
Ingo
|  |