Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Wed, 20 Nov 2019 08:38:55 +0100
Message-ID: <20191120083855.Horde.tWflxXv8u6A3uBxaMJth5g7@messagerie.si.c-s.fr>
From:   Christophe Leroy <christophe.leroy@c-s.fr>
To:     Michael Ellerman <mpe@ellerman.id.au>
Cc:     linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org,
        linux-kernel@vger.kernel.org, dja@axtens.net, npiggin@gmail.com,
        Paul Mackerras <paulus@samba.org>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>
Subject: Re: [PATCH v3 15/15] powerpc/32s: Activate CONFIG_VMAP_STACK
References: <cover.1568106758.git.christophe.leroy@c-s.fr>
 <a99bdfb64e287b16b8cd3f7ec1abfdfb50c7cc64.1568106758.git.christophe.leroy@c-s.fr>
 <875zjgcpyx.fsf@mpe.ellerman.id.au>
In-Reply-To: <875zjgcpyx.fsf@mpe.ellerman.id.au>
User-Agent: Internet Messaging Program (IMP) H5 (6.2.3)
Content-Type: text/plain; charset=UTF-8; format=flowed; DelSp=Yes
MIME-Version: 1.0
Content-Disposition: inline
Content-Transfer-Encoding: 8BIT
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Michael Ellerman <mpe@ellerman.id.au> a écrit :

> Christophe Leroy <christophe.leroy@c-s.fr> writes:
>> 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.
>>
>> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
>> ---
>>  arch/powerpc/kernel/entry_32.S         |  4 +++
>>  arch/powerpc/kernel/head_32.S          | 19 +++++++++++---
>>  arch/powerpc/kernel/head_32.h          |  4 ++-
>>  arch/powerpc/mm/book3s32/hash_low.S    | 46  
>> +++++++++++++++++++++-------------
>>  arch/powerpc/mm/book3s32/mmu.c         |  9 +++++--
>>  arch/powerpc/platforms/Kconfig.cputype |  2 ++
>>  6 files changed, 61 insertions(+), 23 deletions(-)
>
> This is faulting with qemu mac99 model:
>
>   Key type id_resolver registered
>   Key type id_legacy registered
>   BUG: Unable to handle kernel data access on read at 0x2f0db684
>   Faulting instruction address: 0x00004130
>   Oops: Kernel access of bad area, sig: 11 [#1]
>   BE PAGE_SIZE=4K MMU=Hash PowerMac
>   Modules linked in:
>   CPU: 0 PID: 65 Comm: modprobe Not tainted 5.4.0-rc2-gcc49+ #63
>   NIP:  00004130 LR: 000008c8 CTR: b7eb86e0
>   REGS: f106de80 TRAP: 0300   Not tainted  (5.4.0-rc2-gcc49+)
>   MSR:  00003012 <FP,ME,DR,RI>  CR: 4106df38  XER: 20000000
>   DAR: 2f0db684 DSISR: 40000000
>   GPR00: b7ec5d64 f106df38 00000000 bf988a70 00000000 2f0db540  
> b7ec3620 bf988d38
>   GPR08: 10000880 0000d032 72656773 f106df38 b7ed10ec 00000000  
> b7ed3d38 b7ee8900
>   GPR16: bf988d10 00000001 00000000 bf988d10 b7ec3620 bf988d50  
> b7ee76ec b7ee7320
>   GPR24: 10000878 00000000 b7ee8900 00000000 10029f00 10000879  
> b7ee7ff4 bf988d30
>   NIP [00004130] 0x4130
>   LR [000008c8] 0x8c8
>   Call Trace:
>   [f106df38] [c0016224] ret_from_syscall+0x0/0x34 (unreliable)
>   --- interrupt: c01 at 0xb7ed0f50
>       LR = 0xb7ec5d64
>   Instruction dump:
>   db8300e0 XXXXXXXX XXXXXXXX XXXXXXXX fc00048e XXXXXXXX XXXXXXXX XXXXXXXX
>   60a52000 XXXXXXXX XXXXXXXX XXXXXXXX 80850144 XXXXXXXX XXXXXXXX XXXXXXXX
>   ---[ end trace 265da51c6d8b86c5 ]---
>
>
> I think I'll have to drop this series for now.

What about taking the series up to patch 13 ?

I think the problem is related to hash handling as it is working well  
on the 8xx (and on the 83xx which is a nohash book3s). I'll look at  
book3s hash next week.

Christophe