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: <1199932204.6245.110.camel@cinder.waste.org>
Date:	Wed, 09 Jan 2008 20:30:04 -0600
From:	Matt Mackall <mpm@...enic.com>
To:	Pavel Roskin <proski@....org>
Cc:	Arjan van de Ven <arjan@...radead.org>,
	Christoph Hellwig <hch@...radead.org>,
	Benjamin Herrenschmidt <benh@...nel.crashing.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 21:21 -0500, Pavel Roskin wrote:
> On Wed, 2008-01-09 at 20:03 -0600, Matt Mackall wrote:
> 
> > That makes it way too easy for drivers of questionable legality to just
> > clear that bit. Also, we've got a shortage of page bits, etc.
> 
> If we ever have this problem, the bit can be changed in the kernel to
> fool those drivers (I hope the shortage is not so dire that there will
> be no more bits left).

That's what we call an arms race. And yes, page bits are close to
running out on 32-bit.

> I don't think evil drivers should be a problem per se.  There are
> existing non-free drivers that still need to be traced over and over
> again.  I guess ndiswrapper could use tracing for Windows drivers that
> don't know anything about Linux page flags.
> 
> Last but not least, mmiotrace should be useful for free drivers in the
> first place to have a legitimate reason to be in the kernel.

I definitely agree that tracing MMIO is an extremely useful feature.
I've implemented it myself once already for 2.4.

-- 
Mathematics is the supreme nostalgia of our time.

--
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/