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Subject: Re: [PATCH] powerpc/mm: dump block address translation on book3s/32
To:     Michael Ellerman <mpe@ellerman.id.au>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>, npiggin@gmail.com,
        rashmicy@gmail.com
Cc:     linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
References: <26cc609706833f78e3195e3d35c0372b2f40cae3.1542181167.git.christophe.leroy@c-s.fr>
 <878t1uva0q.fsf@concordia.ellerman.id.au>
 <9cb14c1f-02ce-a2a5-94e6-95afb4d3e168@c-s.fr>
 <87o9ap2uif.fsf@concordia.ellerman.id.au>
From:   Christophe LEROY <christophe.leroy@c-s.fr>
Message-ID: <bab9eb25-a6f4-966c-ceaa-00147b50726d@c-s.fr>
Date:   Mon, 3 Dec 2018 18:43:57 +0100
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Le 16/11/2018 à 11:20, Michael Ellerman a écrit :
> Christophe LEROY <christophe.leroy@c-s.fr> writes:
> 
>> Le 15/11/2018 à 12:46, Michael Ellerman a écrit :
>>> Christophe Leroy <christophe.leroy@c-s.fr> writes:
>>>
>>>> This patch adds a debugfs file to dump block address translation:
>>>>
>>>> ~# cat /sys/kernel/debug/block_address_translation
>>>
>>> My instinct is it should be in /sys/kernel/debug/powerpc. But I guess
>>> the other page table dump files are not.
>>
>> Lol.
>>
>> Looks like we have the same instinct ...
>>
>> But you rejected my patch https://patchwork.ozlabs.org/patch/750426/ :)
> 
> Haha. My argument was that the kernel page table dump is not powerpc
> specific, but this file *is* powerpc specific. Though I guess it's in
> the same are as the page table / hash table dump, so it may as well live
> next to them.

I see you took the first version in next-test. It doesn't handle the 
case of 64bits phys addresses. v3 does.

I just sent v4 which does to v3 the changes you did (__init and powerpc/ 
subdir)

Christophe

> 
>>>> diff --git a/arch/powerpc/mm/Makefile b/arch/powerpc/mm/Makefile
>>>> index ca96e7be4d0e..2adad10b5856 100644
>>>> --- a/arch/powerpc/mm/Makefile
>>>> +++ b/arch/powerpc/mm/Makefile
>>>> @@ -47,7 +47,7 @@ ifdef CONFIG_PPC_PTDUMP
>>>>    obj-$(CONFIG_4xx)		+= dump_linuxpagetables-generic.o
>>>>    obj-$(CONFIG_PPC_8xx)		+= dump_linuxpagetables-8xx.o
>>>>    obj-$(CONFIG_PPC_BOOK3E_MMU)	+= dump_linuxpagetables-generic.o
>>>> -obj-$(CONFIG_PPC_BOOK3S_32)	+= dump_linuxpagetables-generic.o
>>>> +obj-$(CONFIG_PPC_BOOK3S_32)	+= dump_linuxpagetables-generic.o dump_bats.o
>>>
>>> BOOK3S_32 covers quite a lot of CPUs.
>>>
>>> But below the only check is that you're on 601 or 603.
>>>
>>> So is the 603 code going to work on all other BOOK3S_32 CPUs?
>>
>> If I understand function setbat() correctly, it should.
>>
>> See
>> https://elixir.bootlin.com/linux/v4.20-rc1/source/arch/powerpc/mm/ppc_mmu_32.c#L115
>> Tell me if you see something I missed.
> 
> I don't know those 32-bit CPUs at all, so as long as you've thought
> about it that's good enough for me. We can catch bugs in testing anyway.
> 
> cheers
>