> On April 20, 2013, 1:42 p.m., Ali Saidi wrote:
> > i'll push it shortly.

I just realized something else last minute.  I don't really know the use case 
for remap.  Should we also invalidate the new_vaddr in the cache?  I don't know 
if a program would ever map onto something else it had already mapped.


- Mitch


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On April 20, 2013, 1:36 p.m., Mitch Hayenga wrote:
> 
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> This is an automatically generated e-mail. To reply, visit:
> http://reviews.gem5.org/r/1830/
> -----------------------------------------------------------
> 
> (Updated April 20, 2013, 1:36 p.m.)
> 
> 
> Review request for Default.
> 
> 
> Description
> -------
> 
> Fixes two bugs relating to software caching of PageTable entries.
> 
> The existing implementation can read uninitialized data or stale information 
> from the cached PageTable entries.
> 
> 1) Add a valid bit for the cache entries.  Simply using zero for the virtual 
> address to signify invalid entries is not sufficient.  Speculative, 
> wrong-path accesses frequently access page zero.  The current implementation 
> would return a uninitialized TLB entry when address zero was accessed and the 
> PageTable cache entry was invalid.
> 
> 2) When unmapping/mapping/remaping a page, invalidate the corresponding 
> PageTable cache entry if one already exists.
> 
> 
> Diffs
> -----
> 
>   src/mem/page_table.hh 745e42ffcc80 
>   src/mem/page_table.cc 745e42ffcc80 
> 
> Diff: http://reviews.gem5.org/r/1830/diff/
> 
> 
> Testing
> -------
> 
> 
> Thanks,
> 
> Mitch Hayenga
> 
>

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