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From:   Michael Ellerman <mpe@ellerman.id.au>
To:     Christophe Leroy <christophe.leroy@csgroup.eu>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>, npiggin@gmail.com
Cc:     linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v2 25/43] powerpc/32: Replace ASM exception exit by C
 exception exit from ppc64
In-Reply-To: <0296d1bc-b37e-43c8-06cf-00ec458fb74e@csgroup.eu>
References: <cover.1615291471.git.christophe.leroy@csgroup.eu>
 <a9a50f475db97fc53795dd778bc14f58029fdd55.1615291473.git.christophe.leroy@csgroup.eu>
 <87tuphkdkz.fsf@mpe.ellerman.id.au>
 <0296d1bc-b37e-43c8-06cf-00ec458fb74e@csgroup.eu>
Date:   Fri, 12 Mar 2021 10:26:02 +1100
Message-ID: <87r1kljmr9.fsf@mpe.ellerman.id.au>
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Christophe Leroy <christophe.leroy@csgroup.eu> writes:
> Le 11/03/2021 =C3=A0 14:46, Michael Ellerman a =C3=A9crit=C2=A0:
>> Christophe Leroy <christophe.leroy@csgroup.eu> writes:
>>> This patch replaces the PPC32 ASM exception exit by C exception exit.
>>>
>>> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
>>> ---
>>>   arch/powerpc/kernel/entry_32.S  | 481 +++++++++-----------------------
>>>   arch/powerpc/kernel/interrupt.c |   4 +
>>>   2 files changed, 132 insertions(+), 353 deletions(-)
>>=20
>> Bisect points to this breaking qemu mac99 for me, with pmac32_defconfig.
>>=20
>> I haven't had time to dig any deeper sorry.
>
> Embarrasing ...

Nah, these things happen.

> I don't get this problem on the 8xx (nohash/32) or the 83xx (book3s/32).
> I don't get this problem with qemu mac99 when using my klibc-based initra=
mfs.
>
> I managed to reproduce it with the rootfs.cpio that I got some time ago f=
rom linuxppc github Wiki.

OK.

I'm using the ppc-rootfs.cpio.gz from here:

  https://github.com/linuxppc/ci-scripts/blob/master/root-disks/Makefile

And the boot script is:

  https://github.com/linuxppc/ci-scripts/blob/master/scripts/boot/qemu-mac99

I've been meaning to write docs on how to use those scripts, but haven't
got around to it.

There's nothing really special though it's just a wrapper around qemu -M ma=
c99.

> I'll investigate it tomorrow.

Thanks.

cheers