mail archive of the barebox mailing list
 help / color / mirror / Atom feed
From: Lucas Stach <l.stach@pengutronix.de>
To: Peter Mamonov <pmamonov@gmail.com>
Cc: barebox@lists.infradead.org
Subject: Re: [PATCH] commands: mem: truncate mem device size to fit the loff_t file size
Date: Wed, 07 Nov 2018 17:08:17 +0100	[thread overview]
Message-ID: <1541606897.2508.55.camel@pengutronix.de> (raw)
In-Reply-To: <20181107134522.y7awdhz2uowjnqh7@localhost.localdomain>

Am Mittwoch, den 07.11.2018, 16:45 +0300 schrieb Peter Mamonov:
> Hi, Lucas,
> 
> On Tue, Nov 06, 2018 at 05:14:07PM +0100, Lucas Stach wrote:
> > On 64bit arches the file covering the whole address space is larger than
> > what can be represented in the loff_t type (s64) used for the file size.
> > Thus the size of this device is interpreted as negative in a lot of
> > places. Fix this by truncating the size to fit the file size type.
> 
> While this is probably an appropriate solution for some architectures, it will 
> cause problems on MIPS64. The root of evil is MIPS64 address space 
> segmentation: https://docplayer.net/docs-images/25/4553906/images/21-0.png).  
> Most notably your patch prevents access to the xkphys segment, where most 
> peripheral devices of a SoC are accessible.

Isn't this a problem for MIPS64 even before my patch? For example the
"mw" command uses open_and_lseek on the dev/mem file with the address
of the write being the seek offset. As this is a loff_t value, seeking
to something with the highest order bit set won't do what you expect to
happen, right?

Regards,
Lucas

_______________________________________________
barebox mailing list
barebox@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/barebox

  reply	other threads:[~2018-11-07 16:08 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-06 16:14 Lucas Stach
2018-11-07  7:47 ` Sascha Hauer
2018-11-07 13:45 ` Peter Mamonov
2018-11-07 16:08   ` Lucas Stach [this message]
2018-11-07 17:07     ` Peter Mamonov

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1541606897.2508.55.camel@pengutronix.de \
    --to=l.stach@pengutronix.de \
    --cc=barebox@lists.infradead.org \
    --cc=pmamonov@gmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox