Re: [PATCH] x86_64 add NX mask for PTE entry

["bibo,mao" <bibo.mao@intel.com>]

Also I think change_page_attr is buggy. if orginal page is not
large page, when that page's previous attr is reverted revert_page()
function will be called to make that page huge. Indeed I think
there is no need to do this.

thanks
bibo,mao

bibo,mao wrote:
> Andi Kleen wrote:
>> On Wednesday 18 October 2006 11:15, bibo,mao wrote:
>>> Hi,
>>>     If function change_page_attr_addr calls revert_page to revert
>>> to original pte value, mk_pte_phys does not mask NX bit. If NX bit
>>> is set on no NX hardware supported x86_64 machine, there is will
>>> be RSVD type page fault and system will crash. This patch adds NX
>>> mask bit for PTE entry.
>>
>> Hmm, weird. I wonder why that didn't trip up earlier. Did you
>> actually see that happening? 
> I remember previous system worked well on 2.6.12 and 2.6.13 version,
> but recently even on older kernel(2.6.9) there will be many times of
> page fault error and system crashes at last when rebooting system.
> 
> I will paste the oops message tomorrow.
> 
> thanks
> bibo,mao
>>
>>
>> -Andi
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