On Wed, Oct 16, 2002 at 04:53:47PM -0700, Kip Walker wrote:
To add a few technical details ...
> 1) 'flush_cache_page' seems to be intended for flushing virtually
> indexed dcaches when a virtual->physical mapping changes (based on
> 2) 'flush_page_to_ram' is also related to avoiding virtual aliasing in
> the dcache (based on VAddr)
Note that flush_page_to_ram is deprecated and should be implement as empty
function for all architecture and the other flushing mechanisms be used
> 3) 'flush_icache_page' seems to be intended for making the icache
> coherent with the dcache after an executable page has been filled
> 4) 'break_cow' may copy an executable page that is marked executable,
> for example a stack page (which has VM_EXEC) and might contain a live
> signal trampoline
> On a CPU with writeback physically indexed/tagged dcache and virtually
> indexed icache that isn't coherent with the dcache, (1) and (2) are NOPs
> and (3) must writeback the dcache and flush the icache.
Yes, where this is getting complicated by some CPUs where remote i-caches
are coherent but the local isn't.