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From: Anton Blanchard <anton@samba.org>
To: Neil Horman <nhorman@tuxdriver.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>,
	linux-kernel@vger.kernel.org, Paul Mackerras <paulus@samba.org>,
	Scott Wood <scottwood@freescale.com>,
	linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH] module: ppc64 module CRC relocation fix causes perf issues
Date: Fri, 26 Jul 2013 11:19:13 +1000	[thread overview]
Message-ID: <20130726111913.201ab9d4@kryten> (raw)
In-Reply-To: <20130725130212.GA19366@hmsreliant.think-freely.org>


Hi Neil,

> Sorry I'm a bit late to the thread, I've ben swamped.  Has someone
> tested this with kexec/kdump?  Thats why the origional patch was
> created, because when kexec loads the kernel at a different physical
> address, the relocations messed with the module crc's, and modules
> couldn't load during the kexec boot.  Assuming that kernaddr_start
> gets set appropriately during boot, using PHYSICAL_START should be
> fine, but I wanted to check, and don't currently have access to a
> powerpc system to do so. Neil

I tested a relocatable kernel forced to run at a non zero physical
address (ie basically kdump). I verified CRCs were bad with your
original patch backed out, and were good with this patch applied.

Anton

WARNING: multiple messages have this Message-ID (diff)
From: Anton Blanchard <anton@samba.org>
To: Neil Horman <nhorman@tuxdriver.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Scott Wood <scottwood@freescale.com>,
	Paul Mackerras <paulus@samba.org>,
	Rusty Russell <rusty@rustcorp.com.au>,
	linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] module: ppc64 module CRC relocation fix causes perf issues
Date: Fri, 26 Jul 2013 11:19:13 +1000	[thread overview]
Message-ID: <20130726111913.201ab9d4@kryten> (raw)
In-Reply-To: <20130725130212.GA19366@hmsreliant.think-freely.org>


Hi Neil,

> Sorry I'm a bit late to the thread, I've ben swamped.  Has someone
> tested this with kexec/kdump?  Thats why the origional patch was
> created, because when kexec loads the kernel at a different physical
> address, the relocations messed with the module crc's, and modules
> couldn't load during the kexec boot.  Assuming that kernaddr_start
> gets set appropriately during boot, using PHYSICAL_START should be
> fine, but I wanted to check, and don't currently have access to a
> powerpc system to do so. Neil

I tested a relocatable kernel forced to run at a non zero physical
address (ie basically kdump). I verified CRCs were bad with your
original patch backed out, and were good with this patch applied.

Anton

  reply	other threads:[~2013-07-26  1:19 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-07-15  4:04 [PATCH] module: ppc64 module CRC relocation fix causes perf issues Anton Blanchard
2013-07-15  4:39 ` Rusty Russell
2013-07-15  8:47 ` Benjamin Herrenschmidt
2013-07-15  8:47   ` Benjamin Herrenschmidt
2013-07-16 22:40   ` Scott Wood
2013-07-16 22:40     ` Scott Wood
2013-07-17  0:04     ` Benjamin Herrenschmidt
2013-07-17  0:04       ` Benjamin Herrenschmidt
2013-07-17  0:08       ` Scott Wood
2013-07-17  0:08         ` Scott Wood
2013-07-18  4:00         ` Anton Blanchard
2013-07-18  4:00           ` Anton Blanchard
2013-07-19 22:59           ` Scott Wood
2013-07-19 22:59             ` Scott Wood
2013-07-23 13:30             ` Michael Ellerman
2013-07-23 13:30               ` Michael Ellerman
2013-07-24 19:22               ` Scott Wood
2013-07-24 19:22                 ` Scott Wood
2013-07-24 22:34             ` Anton Blanchard
2013-07-24 22:34               ` Anton Blanchard
2013-07-24 23:14               ` Benjamin Herrenschmidt
2013-07-24 23:14                 ` Benjamin Herrenschmidt
2013-07-25 13:02                 ` Neil Horman
2013-07-25 13:02                   ` Neil Horman
2013-07-26  1:19                   ` Anton Blanchard [this message]
2013-07-26  1:19                     ` Anton Blanchard
2013-07-26 13:11                     ` Neil Horman
2013-07-26 13:11                       ` Neil Horman

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