linux-kernel - Re: [BUGFIX][PATCH] DO flush icache before set

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Fri, 6 Jul 2007 09:20:22 +0900
From:	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>
To:	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>
Cc:	Mike Stroyan <mike@...oyan.net>, linux-ia64@...r.kernel.org,
	linux-kernel@...r.kernel.org, tony.luck@...el.com,
	linux-mm@...ck.org, clameter@....com, y-goto@...fujitsu.com,
	dmosberger@...il.com, hugh@...itas.com, nickpiggin@...oo.com.au
Subject: Re: [BUGFIX][PATCH] DO flush icache before set_pte() on ia64.

On Fri, 6 Jul 2007 07:18:53 +0900
KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com> wrote:

> On Thu, 5 Jul 2007 12:13:09 -0600
> Mike Stroyan <mike@...oyan.net> wrote:
> >   The L3 cache is involved in the HP-UX defect description because the
> > earlier HP-UX patch PHKL_33781 added flushing of the instruction cache
> > when an executable mapping was removed.  Linux never added that
> > unsuccessfull attempt at montecito cache coherency.  In the current
> > linux situation it can execute old cache lines straight from L2 icache.
> > 
> Hmm... I couldn't understand "why icache includes old lines in a new page."
> This happens at
>  - a file is newly loaded into page-cache.
>  - only on NFS.
>  - happens very *often* if the program is unlucky.
> 
> So I wrote my understainding as I think.
> 
I'll remove reference to HP-UX in the next post. And rewrite all description.

> > 
> >   The only defect that I see in the current implementation of
> > lazy_mmu_prot_update() is that it is called too late in some
> > functions that are already calling it.  Are your large changes
> > attempting to correct other defects?  Or are you simplifying
> > away potentially valuable code because you don't understand it?
> > 
> I know your *simple* patch in April wasn't included. So I wrote this.
> In April thread, commenter's advices was "implement flush_icache_page()" I think.  
> If you have a better patch, please post.
> 
I'll check callers of lazy_mmu_prot_update() again and remove uncecessary calls.
But, basically, i-cache flush will be necessary when VM_EXEC is on. PG_arch_1 will
help us for optimization.

-Kame




-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/