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From: Sascha Hauer <s.hauer@pengutronix.de>
To: Maxime Ripard <maxime.ripard@free-electrons.com>
Cc: barebox@lists.infradead.org
Subject: Re: [PATCH] Add warning above get_ram_size
Date: Thu, 14 Feb 2013 12:35:03 +0100	[thread overview]
Message-ID: <20130214113503.GN1906@pengutronix.de> (raw)
In-Reply-To: <511CB116.8050705@free-electrons.com>

On Thu, Feb 14, 2013 at 10:40:38AM +0100, Maxime Ripard wrote:
> Hi Sascha,
> 
> Le 13/02/2013 18:16, Sascha Hauer a écrit :
> > Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
> > ---
> >  common/memsize.c |    3 +++
> >  1 file changed, 3 insertions(+)
> > 
> > diff --git a/common/memsize.c b/common/memsize.c
> > index d149e41..ef6381b 100644
> > --- a/common/memsize.c
> > +++ b/common/memsize.c
> > @@ -33,6 +33,9 @@
> >   * Check memory range for valid RAM. A simple memory test determines
> >   * the actually available RAM size between addresses `base' and
> >   * `base + maxsize'.
> > + *
> > + * This function modifies the RAM. Do not use it if you're running from
> > + * the RAM you are going to detect!
> >   */
> 
> Actually, I don't see how it modifies the RAM, at least permanently. The
> values it erase are backed up, and there's no concurrency at barebox
> level, so we are sure that the value saved will still be the one that
> would need to be backed up at the end of the function, right?

Yes, it restores the values, but how do you make sure the function does
not modify the instructions you are currently executing? You need bad
luck to hit this, but sooner or later this will happen.

Sascha

-- 
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  reply	other threads:[~2013-02-14 11:35 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-02-13 16:50 [PATCH] cfa10036: Retrieve the RAM size at runtime Maxime Ripard
2013-02-13 17:09 ` Jean-Christophe PLAGNIOL-VILLARD
2013-02-14  9:42   ` Maxime Ripard
2013-02-13 17:16 ` [PATCH] Add warning above get_ram_size Sascha Hauer
2013-02-14  9:40   ` Maxime Ripard
2013-02-14 11:35     ` Sascha Hauer [this message]
2013-02-14 13:59       ` Maxime Ripard
2013-02-14 19:13         ` Sascha Hauer
2013-02-16  8:45           ` Re[2]: " Alexander Shiyan
2013-02-16 15:53             ` Jean-Christophe PLAGNIOL-VILLARD

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