From: Valentine Barshak <vbarshak@ru•mvista.com>
To: Josh Boyer <jwboyer@linux•vnet.ibm.com>
Cc: linuxppc-dev@ozlabs•org, Milton Miller <miltonm@bga•com>
Subject: Re: Sequoia kernel crash workaround.
Date: Thu, 20 Sep 2007 22:13:06 +0400 [thread overview]
Message-ID: <46F2B832.4050905@ru.mvista.com> (raw)
In-Reply-To: <20070920130255.0f6855e1@weaponx.rchland.ibm.com>
Josh Boyer wrote:
> On Thu, 20 Sep 2007 12:32:56 -0500 (CDT)
> Milton Miller <miltonm@bga•com> wrote:
>
>> On Fri Sep 21 02:56:32 EST 2007, Valentine Barshak wrote:
>>> Josh Boyer wrote:
>>>> On Wed, 19 Sep 2007 14:30:24 -0500
>>>> Olof Johansson <olof at lixom.net> wrote:
>>>>
>>>>> On Wed, Sep 19, 2007 at 09:19:47PM +0200, Stefan Roese wrote:
>>>>>> Hi Valentine,
>>>>>>
>>>>>> On Wednesday 19 September 2007, Valentine Barshak wrote:
>>>>>>> Disabling write pipelining really helps.
>>>>>>> Josh, David, what is the right place to put this workaround to?
>>>>>>>
>>>>>>> Is it OK to do mtdcr(PLB4A0_ACR, mfdcr(PLB4A0_ACR) & ~PLB4_WRP); in
>>>>>>> arch/powerpc/boot/cuboot-sequoia.c:sequoia_fixups()?
>>>>>>> or
>>>>>>> should this be done in
>>>>>>> arch/powerpc/platforms/44x/sequoia.c:sequoia_setup_arch()
>>>>>>> with dcr_map, dcr_read/write stuff?
>>>>>> I vote for putting it into sequoia.c, since it's very likely to happen that
>>>>>> Sequoia will at one point be booted without the bootwrapper. Or perhaps it
>>>>>> should go into some common code checking the PVR and disabling it when this
>>>>>> 440EPx/GRx is detected, since all those boards are affected.
>>>>> This is what we have setup_cpu functions in the cpu table for. Please
>>>>> put it there instead of in board code.
>>>> Yes, agreed.
>>> I was thinking about it. Looks like it's the best place, but the code
>>> that actually calls setup_cpu is under ifdef CONFIG_PPC64, while lots of
>>> cpu_setup functions are defined for ppc32 processors.
>>> Is it OK to remove this ifdef, or should I do CONFIG_PPC64 || CONFIG_44x?
>> head_32.S calls call_setup_cpu in misc_32.S to call the cpu setup functon.
>>
>> Note that these functions are called before the kernel is copied down to
>> 0, so on ppc32 you will need the PTRRELOC type stuff. Also the callsite
>> implies that the cpu number is available in r24, which may or may not be
>> true when called from C.
>>
>> Its probably easier to just call call_setup_cpu in the other 32 bit
>> head_xxx files.
>
> Hm. I'll have to see how well that would work for 4xx. Seems 8xx and
> FSL BookE are in a similar situation.
I started preparing the patch after Olof's "take out the ifdef" :)
I've tested it on 4xx. seems to work fine. FPU works OK and EPX/GRX
workaround is fine also, but it has to be tested on 8xx and fsl.
Adding call_setup_cpu to head_44x is no problem.
>
> josh
prev parent reply other threads:[~2007-09-20 18:14 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-09-19 18:39 Sequoia kernel crash workaround Valentine Barshak
2007-09-19 19:12 ` Josh Boyer
2007-09-19 19:19 ` Stefan Roese
2007-09-19 19:30 ` Olof Johansson
2007-09-19 20:08 ` Josh Boyer
2007-09-20 16:56 ` Valentine Barshak
2007-09-20 17:25 ` Olof Johansson
2007-09-20 17:29 ` Josh Boyer
2007-09-23 8:21 ` Benjamin Herrenschmidt
2007-09-24 10:35 ` Valentine Barshak
2007-09-24 20:55 ` Benjamin Herrenschmidt
2007-09-24 21:01 ` Josh Boyer
2007-09-20 18:03 ` Olof Johansson
2007-09-20 17:32 ` Milton Miller
2007-09-20 17:55 ` [PATCH] PowerPC: add setup_cpu for 44x for processor-specific init Valentine Barshak
2007-09-20 18:13 ` Josh Boyer
2007-09-20 18:15 ` Valentine Barshak
2007-09-20 18:54 ` Kumar Gala
2007-09-20 18:55 ` Valentine Barshak
2007-09-21 1:34 ` Paul Mackerras
2007-09-20 18:02 ` Sequoia kernel crash workaround Josh Boyer
2007-09-20 18:13 ` Valentine Barshak [this message]
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