Hi Hugh, -----Original Message----- From: Hugh Dickins [mailto:[EMAIL PROTECTED] Sent: Friday, April 27, 2007 10:34 PM To: Rohit Seth Cc: Nick Piggin; Mike Stroyan; Andrew Morton; Luck, Tony; [EMAIL PROTECTED]; linux-kernel@vger.kernel.org Subject: Re: Fw: [PATCH] ia64: race flushing icache in do_no_page path
On Fri, 27 Apr 2007, Rohit Seth wrote: > lazy_mmu_prot_update was added specifically for notifying change in > protection. So, in a way it is closer to update_mmu_cache (Which is > for change in mappings itself). Though for ia64 implementation, this > ends up flushing the icaches when needed. >The ia64 implementation is the only one which has any use for it, Even Itanium didn't need it for almost 5 years :) Though I think archs that have incoherent I & D caches could be (theoritically) exposed to same (original) mprotect code path bug that triggered this API. >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. Cheers, -rohit - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
