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From: Paul Mackerras <paulus@samba.org>
To: Milton Miller <miltonm@bga.com>,
	Ben Herrenschmidt <benh@kernel.crashing.org>,
	linuxppc-dev@ozlabs.org,
	Michael Ellerman <michael@ellerman.id.au>,
	kexec@lists.infradead.org, Simon Horman <horms@verge.net.au>
Subject: Re: [PATCH 3/3] powerpc/ppc64/kdump: better flag for running relocatable
Date: Thu, 23 Oct 2008 14:43:54 +1100	[thread overview]
Message-ID: <18687.62202.333736.269891@drongo.ozlabs.ibm.com> (raw)
In-Reply-To: <18687.61506.924500.411952@drongo.ozlabs.ibm.com>

Paul Mackerras writes:
> Milton Miller writes:
> 
> > Move the flag to 0x5c, 1 word before the secondary cpu entry point at
> > 0x60.  Use the copy at address 0 not the one in the base kernel image to
> > make it easier on kexec-tools.
> 
> Why is it easier on kexec-tools?  Doesn't kexec-tools know where it
> put the kernel?
> 
> I'd much rather keep the flag inside the kdump kernel image, rather
> than having kexec/kdump start using random fixed locations outside the
> new kernel image.

In fact the cliching argument is that when the kernel is loaded by OF
or yaboot, we have no way to tell what will be at location 0x5c,
whereas we know that the word at offset 0x5c in the kernel image will
have been initialized to 0.  So we had better put the flag inside the
kernel image.

Paul.

  reply	other threads:[~2008-10-23  3:43 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-10-22  4:56 [PATCH] Support for relocatable kdump kernel Milton Miller
2008-10-22 20:39 ` [PATCH 3/3] powerpc/ppc64/kdump: better flag for running relocatable Milton Miller
2008-10-23  3:23   ` Michael Neuling
2008-10-23  3:32   ` Paul Mackerras
2008-10-23  3:43     ` Paul Mackerras [this message]
2008-10-24  4:41       ` Michael Neuling
2008-11-07 13:52       ` Milton Miller
2008-10-23 15:15   ` Mohan Kumar M
2008-11-07 13:59     ` Milton Miller
2008-11-10 15:22       ` Mohan Kumar M
2008-11-11 16:06         ` Milton Miller
2008-10-22 20:39 ` [PATCH 1/2 kexec-tools] ppc64: new relocatble kernel activation ABI Milton Miller
2008-10-22 20:39 ` [PATCH 2/2 kexec-tools] ppc64: segemments are sorted Milton Miller
2008-10-22 20:47   ` Milton Miller
2008-10-22 20:39 ` [PATCH 1/3] powerpc: kexec exit should not use magic numbers Milton Miller
2008-10-22 23:18   ` Simon Horman

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