From: Sascha Hauer <s.hauer@pengutronix.de>
To: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Cc: barebox@lists.infradead.org
Subject: Re: [PATCH 1/1] arm: mmu: catch NULL pointer dereferences
Date: Wed, 4 Sep 2013 09:07:04 +0200 [thread overview]
Message-ID: <20130904070704.GI30088@pengutronix.de> (raw)
In-Reply-To: <20130902102406.GK19197@ns203013.ovh.net>
On Mon, Sep 02, 2013 at 12:24:06PM +0200, Jean-Christophe PLAGNIOL-VILLARD wrote:
> On 11:05 Mon 02 Sep , Sascha Hauer wrote:
> > On Sat, Aug 31, 2013 at 05:54:22PM +0200, Jean-Christophe PLAGNIOL-VILLARD wrote:
> > > For high vectors if memory start at 0x0. We have to
> > > live without being able to catch NULL pointer dereferences.
> > >
> > Why not add the check to vectors_init() instead of passing this as
> > argument?
> >
> > I must say I'm not entirely happy with this approach. Being able to
> > catch NULL pointer derefs is really a good thing. When exactly does the
> > faulting zero SDRAM page become a problem for you? obviously something
> > like
> >
> > cp /somehing /dev/ram0
> >
> > does not work. Some care must probably be taken when setting up the
> > kernel parameters. Are these the problems or is there something else?
> yes it's get issue with uImage that get data load there :(
>
> as I can not control the load addr from uImage :(
>
> and on ux5x0 and arm board I have ddr starting at 0x0
Maybe we should add some hook which dynamically enables/disables the
zero page. The bootm code could then disable it.
Anyway, for now we can also apply the current patch, but please move the
is_start_zero test to vectors_init().
Sascha
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prev parent reply other threads:[~2013-09-04 7:07 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-31 15:54 Jean-Christophe PLAGNIOL-VILLARD
2013-09-02 9:05 ` Sascha Hauer
2013-09-02 10:24 ` Jean-Christophe PLAGNIOL-VILLARD
2013-09-04 7:07 ` Sascha Hauer [this message]
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