Re: Fw: [PATCH] ia64: race flushing icache in do_no_page path

[Nick Piggin <nickpiggin@yahoo.com.au>]

Rohit Seth wrote:

>>and 
>>it's only interested when it's executable i.e. "lazy_mmu_prot_update"
>>is a name concealing some overdesign.
> 
> 
> You are right that ia64 is only interested in whne the execute permissions
> kick in (and FWIW ia64 used to use update_mmu_cache API to do what it is now
> doing lazy_mmu_prot_update).  Though the idea was to design an API that any
> arch can use to know when ever there is change in protections on a mapping.

What I think what we should do is audit flush_icache_page coverage, and
convert ia64 to use that (because it needs this to happen _before_ the
pte is set).

All we should need to do is add a pte argument to flush_icache, and it
should be possible to do what ia64 wants, and we can remove
lazy_mmu_prot_update (or at least rename it to something like
flush_icache_page_chprot and move it to the normal flush_icache_page
position above set_pte if not all architectures want their
flush_icache_page called at protection change time).

-- 
SUSE Labs, Novell Inc.