From: Michal Sojka <sojkam1@fel•cvut.cz>
To: christophe leroy <christophe.leroy@c-s•fr>
Cc: Scott Wood <scottwood@freescale•com>, linuxppc-dev@lists•ozlabs.org
Subject: Re: memcpy regression
Date: Sun, 06 Sep 2015 21:05:15 +0200 [thread overview]
Message-ID: <87twr74bdg.fsf@steelpick.2x.cz> (raw)
In-Reply-To: <55EBF6CD.5010001@c-s.fr>
On Sun, Sep 06 2015, christophe leroy wrote:
> Le 05/09/2015 02:08, Michal Sojka a =C3=A9crit :
>> On 4.9.2015 21:49, Michal Sojka wrote:
>>> On 4.9.2015 20:10, christophe leroy wrote:
>>>>
>>>>
>>>> Le 04/09/2015 16:35, Michal Sojka a =C3=A9crit :
>>>>> On Fri, Sep 04 2015, Christophe LEROY wrote:
>>>>>> Le 04/09/2015 15:33, Michal Sojka a =C3=A9crit :
>>>>>>> Dear Christophe,
>>>>>>>
>>>>>>> my MPC5200-based system stopped booting recently. I bisected the=20
>>>>>>> problem
>>>>>>> to your commit below. If I revert that commit (on top of
>>>>>>> 807249d3ada1ff28a47c4054ca4edd479421b671 =3D v4.2-6663-g807249d), my
>>>>>>> system boots again.
>>>>>>>
>>>>>>>
>>>>>> Do you use mainline code only, or do you have home-made code ?
>>>>> I use mainline only sources with non-mainline device-tree.
>>>>>
>>>>>> memcpy() is not supposed to be used on non-cacheable memory.
>>>>>> memcpy_toio() is the function to use when copying to non-cacheble=20
>>>>>> area.
>>>>>>
>>>>>> When I submitted the patch, I looked for erroneous use of memcpy()=20
>>>>>> and
>>>>>> memset().
>>>>>> I found one wrong use of memset() that I changed to memset_io() but I
>>>>>> didn't find any misuse of memcpy().
>>>>>> But I may have missed one.
>>>>> I attach my .config, if it helps. I have there
>>>>>
>>>>> CONFIG_PPC_MPC52xx=3Dy
>>>>> CONFIG_PPC_MPC5200_SIMPLE=3Dy
>>>>>
>>>>> so arch/powerpc/platforms/52xx is probably the directory to look.=20
>>>>> Do you
>>>>> see any mempcy misuse there?
>>>> I only found one suspect use of memcpy() in=20
>>>> arch/powerpc/platforms/52xx/
>>>> It is in mpc52xx_pm.c but it's linked to CONFIG_PM which is not=20
>>>> selected by your .config
>>>> I'll check in the drivers selected by your .config
>>>>
>>>> In parallele, are you able to try with CONFIG_PPC_EARLY_DEBUG in=20
>>>> order to try and locate the blocking point ?
>>> I don't get any output from the system even with CONFIG_PPC_EARLY_DEBUG.
>>
>> Hmm, there is no udbg console for MPC5200. I hacked something up and=20
>> the earliest place I was able to initialize it is after=20
>> early_init_devtree() in setup_32.c. Even with this console, I got no=20
>> output when the problematic patch was applied. So the problem is=20
>> somewhere earlier.
>>
>
> In early_init() in setup_32.c, there is the following comment:
> /* First zero the BSS -- use memset_io, some platforms don't have caches=
=20
> on yet */
>
> In that case, when does cache get activated ?
>
> In move_device_tree(), called from early_init_devtree(), there is a call=
=20
> to memcpy().
> Can you try replacing it by memcpy_io() ?
I tried replacing it by memcpy_toio(), memcpy_fromio() and by
generic_memcpy(). Nothing helped :(
-Michal
next prev parent reply other threads:[~2015-09-06 19:05 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-04 13:33 memcpy regression Michal Sojka
2015-09-04 13:57 ` Christophe LEROY
2015-09-04 14:35 ` Michal Sojka
2015-09-04 18:10 ` christophe leroy
2015-09-04 19:49 ` Michal Sojka
2015-09-05 0:08 ` Michal Sojka
2015-09-06 8:18 ` christophe leroy
2015-09-06 19:05 ` Michal Sojka [this message]
2015-09-06 21:01 ` Michal Sojka
2015-09-07 1:14 ` Michael Ellerman
2015-09-07 7:08 ` Christophe LEROY
2015-09-07 8:40 ` Michael Ellerman
2015-09-07 9:45 ` Michal Sojka
2015-09-07 10:59 ` David Laight
2015-09-08 3:54 ` Michael Ellerman
2015-09-08 8:59 ` David Laight
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