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Subject: Re: [PATCH v6 10/18] sh/tlb: Convert SH to generic mmu_gather
To:     Geert Uytterhoeven <geert@linux-m68k.org>,
        Peter Zijlstra <peterz@infradead.org>
Cc:     Will Deacon <will.deacon@arm.com>,
        "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Nicholas Piggin <npiggin@gmail.com>,
        Linux-Arch <linux-arch@vger.kernel.org>,
        Linux MM <linux-mm@kvack.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Russell King <linux@armlinux.org.uk>,
        Heiko Carstens <heiko.carstens@de.ibm.com>,
        Rik van Riel <riel@surriel.com>,
        Yoshinori Sato <ysato@users.sourceforge.jp>,
        Rich Felker <dalias@libc.org>,
        Linux-sh list <linux-sh@vger.kernel.org>
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 <20190219103233.443069009@infradead.org>
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From:   Guenter Roeck <linux@roeck-us.net>
Message-ID: <156fa92f-4c5a-08bd-bcda-20029724c0de@roeck-us.net>
Date:   Wed, 4 Dec 2019 05:22:28 -0800
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On 12/4/19 4:32 AM, Geert Uytterhoeven wrote:
> Hoi Peter,
> 
> On Wed, Dec 4, 2019 at 11:48 AM Peter Zijlstra <peterz@infradead.org> wrote:
>> On Tue, Dec 03, 2019 at 12:19:00PM +0100, Geert Uytterhoeven wrote:
>>> On Tue, Feb 19, 2019 at 11:35 AM Peter Zijlstra <peterz@infradead.org> wrote:
>>>> Generic mmu_gather provides everything SH needs (range tracking and
>>>> cache coherency).
>>>>
>>>> Cc: Will Deacon <will.deacon@arm.com>
>>>> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
>>>> Cc: Andrew Morton <akpm@linux-foundation.org>
>>>> Cc: Nick Piggin <npiggin@gmail.com>
>>>> Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
>>>> Cc: Rich Felker <dalias@libc.org>
>>>> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
>>>
>>> I got remote access to an SH7722-based Migo-R again, which spews a long
>>> sequence of BUGs during userspace startup.  I've bisected this to commit
>>> c5b27a889da92f4a ("sh/tlb: Convert SH to generic mmu_gather").
>>
>> Whoopsy.. also, is this really the first time anybody booted an SH
>> kernel in over a year ?!?
> 
> Nah, but the v5.4-rc3 I booted recently on qemu -M r2d had
> CONFIG_PGTABLE_LEVELS=2, so it didn't show the problem.
> 

Guess that explains why I do not see the problem with my qemu boots.
I use rts7751r2dplus_defconfig. Is it possible to reproduce the problem
with qemu ? I don't think so, but maybe I am missing something.

Guenter

>>> Do you have a clue?
>>
>> Does the below help?
> 
> Unfortunately not.
> 
>> diff --git a/arch/sh/include/asm/pgalloc.h b/arch/sh/include/asm/pgalloc.h
>> index 22d968bfe9bb..73a2c00de6c5 100644
>> --- a/arch/sh/include/asm/pgalloc.h
>> +++ b/arch/sh/include/asm/pgalloc.h
>> @@ -36,9 +36,8 @@ do {                                                  \
>>   #if CONFIG_PGTABLE_LEVELS > 2
>>   #define __pmd_free_tlb(tlb, pmdp, addr)                        \
>>   do {                                                   \
>> -       struct page *page = virt_to_page(pmdp);         \
>> -       pgtable_pmd_page_dtor(page);                    \
>> -       tlb_remove_page((tlb), page);                   \
>> +       pgtable_pmd_page_dtor(pmdp);                    \
> 
> expected ‘struct page *’ but argument is of type ‘pmd_t * {aka struct
> <anonymous> *}’
> 
>> +       tlb_remove_page((tlb), (pmdp));                 \
> 
> likewise
> 
>>   } while (0);
>>   #endif
> 
> Gr{oetje,eeting}s,
> 
>                          Geert
>