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Subject: Re: [PATCH v5 17/17] powerpc/32s: Enable CONFIG_VMAP_STACK
To:     Christophe Leroy <christophe.leroy@c-s.fr>
Cc:     linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        Paul Mackerras <paulus@samba.org>,
        linuxppc-dev@lists.ozlabs.org, dja@axtens.net
References: <cover.1576916812.git.christophe.leroy@c-s.fr>
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 <20200206203146.GA23248@roeck-us.net>
 <c6285f2a-f8f5-0d97-2d80-061da1f1a7fc@c-s.fr>
 <0f866131-4292-a66b-2637-c34139277486@c-s.fr>
 <551bad84-3e80-265b-93ab-25eae4aa9807@roeck-us.net>
 <29bd8702-9b8f-6931-2bbc-db7e444907d5@c-s.fr>
From:   Guenter Roeck <linux@roeck-us.net>
Message-ID: <d6158967-fde3-1a87-44b6-07638bd2b5b0@roeck-us.net>
Date:   Fri, 7 Feb 2020 05:44:52 -0800
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On 2/7/20 5:29 AM, Christophe Leroy wrote:
> 
> 
> On 02/07/2020 01:08 PM, Guenter Roeck wrote:
>> On 2/7/20 12:28 AM, Christophe Leroy wrote:
>>>
>>>
>>> On 02/07/2020 06:13 AM, Christophe Leroy wrote:
>>>>
>>>>
>>>> Le 06/02/2020 à 21:31, Guenter Roeck a écrit :
>>>>> On Sat, Dec 21, 2019 at 08:32:38AM +0000, Christophe Leroy wrote:
>>>>>> A few changes to retrieve DAR and DSISR from struct regs
>>>>>> instead of retrieving them directly, as they may have
>>>>>> changed due to a TLB miss.
>>>>>>
>>>>>> Also modifies hash_page() and friends to work with virtual
>>>>>> data addresses instead of physical ones. Same on load_up_fpu()
>>>>>> and load_up_altivec().
>>>>>>
>>>>>> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
>>>>>
>>>>> This patch results in qemu boot failures (mac99 with pmac32_defconfig).
>>>>> Images fail silently; there is no console output. Reverting the patch
>>>>> fixes the problem. Bisect log is attached below.
>>>>>
>>>>> Assuming this was tested on real hardware, am I correct to assume that qemu
>>>>> for ppc32 (more specifically, qemu's mac99 and g3beige machines) no longer
>>>>> works with the upstream kernel ?
>>>>
>>>> Before submitting the series, I successfully tested:
>>>> - Real HW with powerpc 8xx
>>>> - Real HW with powerpc 832x
>>>> - Qemu's mac99
>>>>
>>>> I'll re-check the upstream kernel.
>>>>
>>>
>>> This is still working for me with the upstream kernel:
>>>
>>
>> Interesting. What is your kernel configuration, your qemu version, and
>> your qemu command line ?
> 
> Config is pmac32_defconfig + CONFIG_DEVTMPFS (But kernel also boots without CONFIG_DEVTMPFS)
> 
> QEMU emulator version 2.11.2
> 
> qemu-system-ppc -kernel vmlinux -M mac99 -initrd rootfs.cpio.gz -s -m 1024
> 
> Works with both GCC 5.5 and GCC 8.1
> 
Actually, the problem is that I have locking selftest options enabled
in my tests. Everything works if I disable those. The "culprit" seems
to be CONFIG_PROVE_LOCKING. Can you retest with CONFIG_PROVE_LOCKING=y ?

Thanks,
Guenter