Re: [PATCH 1/3] Fix COW D-cache aliasing on fork

[Russell King <rmk+lkml@arm.linux.org.uk>]

On Fri, Oct 20, 2006 at 02:12:11PM -0700, Linus Torvalds wrote:
> On Fri, 20 Oct 2006, Russell King wrote:
> > Well, looking at do_wp_page() I'm now quite concerned about ARM and COW.
> > I can't see how this code could _possibly_ work with a virtually indexed
> > cache as it stands.  Yet, the kernel does appear to work.
> 
> It really shouldn't need any extra code, exactly because by the time it 
> hits any page-fault, the caches had better be in sync with the physical 
> page contents _anyway_ (yes, being virtual, the caches will _duplicate_ 
> the contents, but since the pages are read-only, that aliasing should be 
> perfectly fine).

Oh, of course!  That explains why it actually works as expected!  Thanks
for filling back in that bit of swapped-out-years-ago-and-lost information.

-- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of:  2.6 Serial core