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From: Vivek Goyal <vgoyal@in.ibm.com>
To: Andi Kleen <ak@suse.de>
Cc: Kexec Mailing List <kexec@lists.infradead.org>,
	linux-kernel@vger.kernel.org, Jurriaan <thunder7@xs4all.nl>,
	Helge Hafting <helgehaf@aitel.hist.no>,
	Horms <horms@verge.net.au>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 1/2] x86_64: Reflect the relocatability of the kernel in the ELF header.
Date: Tue, 1 May 2007 09:25:39 +0530	[thread overview]
Message-ID: <20070501035539.GA15472@in.ibm.com> (raw)
In-Reply-To: <200704301717.08230.ak@suse.de>

On Mon, Apr 30, 2007 at 05:17:07PM +0200, Andi Kleen wrote:
> On Monday 30 April 2007 17:12:39 Eric W. Biederman wrote:
> > 
> > Currently because vmlinux does not reflect that the kernel is relocatable
> > we still have to support CONFIG_PHYSICAL_START.  So this patch adds a small
> > c program to do what we cannot do with a linker script set the elf header
> > type to ET_DYN.
> > 
> > Since last time I have fixed the type to be in my code ET_DYN (oops),
> > and verified this works with kexec.  I realized while testing that we
> > don't have anyway of identifying a kernel vmlinux as linux so we
> > probably want to add an ELF note but that will be another patch.
> 
> The patch is ok for me, but does it pass Vivek's usual testing?

I am facing one issue with this patch. gdb can not analyze the
resulting kernel core file. Looks like gdb treats vmlinux differently if
ELF header type is "ET_DYN". It reads the symbol values incorrectly.

For example, symbol value of "panic_timeout" is 0xffffffff808a1fa8 but
gdb somehow things that it is 0xffffffff008aaebf. Looks like it is
performing some relocation.

I am using GNU gdb Red Hat Linux (6.5-5.fc6rh).

Thanks
Vivek

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WARNING: multiple messages have this Message-ID (diff)
From: Vivek Goyal <vgoyal@in.ibm.com>
To: Andi Kleen <ak@suse.de>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>,
	Kexec Mailing List <kexec@lists.infradead.org>,
	Jurriaan <thunder7@xs4all.nl>,
	linux-kernel@vger.kernel.org,
	Helge Hafting <helgehaf@aitel.hist.no>,
	Horms <horms@verge.net.au>,
	Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 1/2] x86_64: Reflect the relocatability of the kernel in the ELF header.
Date: Tue, 1 May 2007 09:25:39 +0530	[thread overview]
Message-ID: <20070501035539.GA15472@in.ibm.com> (raw)
In-Reply-To: <200704301717.08230.ak@suse.de>

On Mon, Apr 30, 2007 at 05:17:07PM +0200, Andi Kleen wrote:
> On Monday 30 April 2007 17:12:39 Eric W. Biederman wrote:
> > 
> > Currently because vmlinux does not reflect that the kernel is relocatable
> > we still have to support CONFIG_PHYSICAL_START.  So this patch adds a small
> > c program to do what we cannot do with a linker script set the elf header
> > type to ET_DYN.
> > 
> > Since last time I have fixed the type to be in my code ET_DYN (oops),
> > and verified this works with kexec.  I realized while testing that we
> > don't have anyway of identifying a kernel vmlinux as linux so we
> > probably want to add an ELF note but that will be another patch.
> 
> The patch is ok for me, but does it pass Vivek's usual testing?

I am facing one issue with this patch. gdb can not analyze the
resulting kernel core file. Looks like gdb treats vmlinux differently if
ELF header type is "ET_DYN". It reads the symbol values incorrectly.

For example, symbol value of "panic_timeout" is 0xffffffff808a1fa8 but
gdb somehow things that it is 0xffffffff008aaebf. Looks like it is
performing some relocation.

I am using GNU gdb Red Hat Linux (6.5-5.fc6rh).

Thanks
Vivek

  reply	other threads:[~2007-05-01  3:55 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-04-30 15:12 [PATCH 1/2] x86_64: Reflect the relocatability of the kernel in the ELF header Eric W. Biederman
2007-04-30 15:12 ` Eric W. Biederman
2007-04-30 15:17 ` Andi Kleen
2007-04-30 15:17   ` Andi Kleen
2007-05-01  3:55   ` Vivek Goyal [this message]
2007-05-01  3:55     ` Vivek Goyal
2007-05-01  4:20     ` Eric W. Biederman
2007-05-01  4:20       ` Eric W. Biederman
2007-05-01  5:06       ` Vivek Goyal
2007-05-01  5:06         ` Vivek Goyal
2007-05-01  5:26         ` Eric W. Biederman
2007-05-01  5:26           ` Eric W. Biederman
2007-05-01  6:25           ` Andi Kleen
2007-05-01  6:25             ` Andi Kleen
2007-05-01  5:54             ` Eric W. Biederman
2007-05-01  5:54               ` Eric W. Biederman
2007-05-01  6:44               ` Vivek Goyal
2007-05-01  6:44                 ` Vivek Goyal
2007-05-28 10:54         ` Bernhard Walle
2007-05-28 10:54           ` Bernhard Walle
2007-05-28 11:09           ` Vivek Goyal
2007-05-28 11:09             ` Vivek Goyal
2007-05-28 14:39             ` Bernhard Walle
2007-05-28 14:39               ` Bernhard Walle
2007-06-01 12:26               ` Bernhard Walle
2007-06-01 12:26                 ` Bernhard Walle
2007-05-28 14:57           ` Andi Kleen
2007-05-28 14:57             ` Andi Kleen
  -- strict thread matches above, loose matches on Subject: below --
2007-03-31  7:53 2.6.21-rc5-mm3 - no boot, "address not 2M aligned" Andrew Morton
2007-04-01  5:29 ` thunder7
2007-04-01  6:15   ` Eric W. Biederman
2007-04-01  6:29     ` Andrew Morton
2007-04-02  7:41       ` Vivek Goyal
2007-04-02  8:43         ` Eric W. Biederman
2007-04-02  9:45           ` Vivek Goyal
2007-04-02 17:26             ` Eric W. Biederman
2007-04-03  4:01               ` Vivek Goyal
2007-04-03  5:23                 ` Eric W. Biederman
2007-04-03 10:03                   ` Vivek Goyal
2007-04-23  5:12                     ` [PATCH 1/2] x86_64: Reflect the relocatability of the kernel in the ELF header Eric W. Biederman
2007-04-23  5:12                       ` Eric W. Biederman
2007-04-24  6:31                       ` Vivek Goyal
2007-04-24  6:31                         ` Vivek Goyal
2007-04-24  7:21                         ` Eric W. Biederman
2007-04-24  7:21                           ` Eric W. Biederman

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