Re: [PATCH] scripts: make extract-vmlinux support armel/armhf - Russell King

From: Russell King - ARM Linux <linux@armlinux.org.uk>
To: Tony Lindgren <tony@atomide.com>
Cc: Roger Shimizu <rogershimizu@gmail.com>,
	Corentin Chary <corentincj@iksaif.net>,
	Masahiro Yamada <yamada.masahiro@socionext.com>,
	Michal Marek <mmarek@suse.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-kbuild@vger.kernel.org
Subject: Re: [PATCH] scripts: make extract-vmlinux support armel/armhf
Date: Sat, 2 Sep 2017 00:16:54 +0100	[thread overview]
Message-ID: <20170901231654.GY20805@n2100.armlinux.org.uk> (raw)
In-Reply-To: <20170831174318.GM6008@atomide.com>

On Thu, Aug 31, 2017 at 10:43:19AM -0700, Tony Lindgren wrote:
> * Russell King - ARM Linux <linux@armlinux.org.uk> [170831 09:21]:
> > On Fri, Sep 01, 2017 at 01:05:16AM +0900, Roger Shimizu wrote:
> > > On Fri, Sep 1, 2017 at 12:49 AM, Russell King - ARM Linux
> > > <linux@armlinux.org.uk> wrote:
> > > > What's the use case - what are you using the output of this script with?
> > > 
> > > I already provided a use case, to trace a Debian kernel issue caused
> > > by kernel size.
> > > - https://bugs.debian.org/870185#50
> > 
> > Sorry, I haven't time to look - it needs me to use firefox on a
> > different machine.  Maybe you could help by providing some details
> > by email, otherwise I've got extra work to do at some point in the
> > future (probably days away) if I remember (your mail will get buried).
> > Much of my time is in front of a _textual_ _only_ interface, and elinks
> > does not work with several modern SSL-only sites.
> > 
> > > I also see other people complaining this issue:
> > >  - https://bugs.launchpad.net/linaro-ubuntu/+bug/1050453
> > >  - https://bugs.linaro.org/show_bug.cgi?id=461
> > > 
> > > By a random web search, I find another blog post on how to dissamble the kernel.
> > >  - https://blog.packagecloud.io/eng/2016/03/08/how-to-extract-and-disassmble-a-linux-kernel-image-vmlinuz/
> > 
> > Yea, all SSL sites, I'm not going to try elinks with them, I don't
> > have the time to mess around.
> 
> I think the use case is to get the booted kernel size from zImage
> to avoid overwriting dts or initramfs. Don't we already have that
> at the end of zImage somewhere for kexec?

We do, but finding where that is is difficult if a DTB has been appended
as it's right at the end of the compressed data.  kexec doesn't use it,
it just assumes there's a 5x expansion of the kernel compressed image.

-- 
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
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