Re: [PATCH 1/2] x86-32: Fix crashes with CPU hotplug on AMD machines

["H. Peter Anvin" <hpa@zytor.com>]

On 08/12/2010 07:41 AM, Joerg Roedel wrote:
> On Thu, Aug 05, 2010 at 07:14:14AM -0700, H. Peter Anvin wrote:
>> On 08/05/2010 12:45 AM, Roedel, Joerg wrote:
>> Correct, again.  It's unclear to me if we can get away with the very
>> simple 64-bit approach -- in particular, not including all the 1:1
>> mappings in the kernel -- for all future users, though.
> 
> Yeah, We could probably use the same symbol names for the trampoline and
> the swapper page-table on 32 and 64 bit and merge the code that handles
> it between the architectures. Shouldn't be too difficult. We cook
> something up :-)
> But do you mind to take this patch first? It fixes the occurence of an
> erratum on AMD hardware, it is a quite simple fix compared to the rework
> suggested. In fact, I would like to have a simple patch to fix the
> problem first (and backport it as necessary) and then go the way to
> rework the current code differences between 32 and 64 bit.
> 

Agreed.  I do have a concern about the kernel page tables not being
synchronized into trampoline_pg_dir (it's only an issue for 32-bit
!PAE), so at the very least we need to keep an eye out for it...

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.