linux-kernel - Re: Replacement for page fault notifiers?

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]

Message-Id: <1199926725.6734.161.camel@pasglop>
Date:	Thu, 10 Jan 2008 11:58:45 +1100
From:	Benjamin Herrenschmidt <benh@...nel.crashing.org>
To:	Arjan van de Ven <arjan@...radead.org>
Cc:	Andi Kleen <andi@...stfloor.org>,
	Christoph Hellwig <hch@...radead.org>,
	Pavel Roskin <proski@....org>, Dave Airlie <airlied@...il.com>,
	Pekka Paalanen <pq@....fi>, linux-kernel@...r.kernel.org,
	jbeulich@...ell.com
Subject: Re: Replacement for page fault notifiers?


On Wed, 2008-01-09 at 16:55 -0800, Arjan van de Ven wrote:
> > That would assume that your mmio area has a struct page. In most
> PCs 
> > the ones in the PCI hole don't
> > 
> 
> so you also call the function for all traps on pages without struct
> page;
> that should be extremely rare anyway, and the mmio_trace code can
> then 
> look the page up.

Not that rare if you use a modern DRI :-)

In fact, the thing here is that it's mostly kernel mappings though, not
user mappings. So we never get there, we die before we even reach
generic code most of the time iirc.

The whole ioremap stuff is very platform specific, not everybody even
uses the code in mm/vmalloc.c for it, so at this stage, I see no other
option but a hook in do_page_fault().

Cheers,
Ben.

--
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/