linux-kernel - Re: [PATCH] mm: hugetlb: flush dcache before returning zeroed huge page to userspace

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] [day] [month] [year] [list]

Message-ID: <20120816183255.GB19401@mudshark.cambridge.arm.com>
Date:	Thu, 16 Aug 2012 19:32:56 +0100
From:	Will Deacon <will.deacon@....com>
To:	Michal Hocko <mhocko@...e.cz>
Cc:	Hugh Dickins <hughd@...gle.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Hillf Danton <dhillf@...il.com>,
	Russell King <linux@....linux.org.uk>,
	"linux-arch@...r.kernel.org" <linux-arch@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-mm@...ck.org" <linux-mm@...ck.org>
Subject: Re: [PATCH] mm: hugetlb: flush dcache before returning zeroed huge
 page to userspace

On Thu, Aug 16, 2012 at 07:20:15PM +0100, Michal Hocko wrote:
> On Thu 16-08-12 17:09:54, Will Deacon wrote:
> > +static inline void arch_clear_hugepage_flags(struct page *page)
> > +{
> > +	flush_dcache_page(page);
> > +}
> > +
> 
> Why do we need the hook for ia64? hugetlb_no_page calls clear_huge_page
> and that one calls flush_dcache_page (via clear_user_page), right?
> The same applies to copy_huge_page for COW.

You're right, these are redundant for ppc and ia64 (although ppc does have a
comment moaning about the flush). Looks like it's just sh and ARM that need to
do anything.

Cheers,

Will
--
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/