From: Christophe Leroy <christophe.leroy@csgroup.eu>
To: Michael Ellerman <mpe@ellerman.id.au>,
Nicholas Piggin <npiggin@gmail.com>
Cc: "linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] powerpc/85xx: Fix math emulation exception
Date: Tue, 10 Oct 2023 10:55:54 +0000 [thread overview]
Message-ID: <c259a5a2-8ef5-42eb-0b1f-0f0e1ff70c26@csgroup.eu> (raw)
In-Reply-To: <8734yisqmh.fsf@mail.lhotse>
Le 10/10/2023 à 12:45, Michael Ellerman a écrit :
> Christophe Leroy <christophe.leroy@csgroup.eu> writes:
>> Booting mpc85xx_defconfig kernel on QEMU leads to:
>
> What machine/CPU model are you using for that?
If I remember correctly, it was machine mpc8544ds.
Christophe
>
> I tried ppce500/e500 and that is working OK for me, ie. boots to
> userspace and I see math instructions being emulated via the emulated
> stats.
>
> cheers
>
>> Bad trap at PC: fe9bab0, SR: 2d000, vector=800
>> awk[82]: unhandled trap (5) at 0 nip fe9bab0 lr fe9e01c code 5 in libc-2.27.so[fe5a000+17a000]
>> awk[82]: code: 3aa00000 3a800010 4bffe03c 9421fff0 7ca62b78 38a00000 93c10008 83c10008
>> awk[82]: code: 38210010 4bffdec8 9421ffc0 7c0802a6 <fc00048e> d8010008 4815190d 93810030
>> Trace/breakpoint trap
>> WARNING: no useful console
>>
>> This is because allthough CONFIG_MATH_EMULATION is selected,
>> Exception 800 calls unknown_exception().
>>
>> Call emulation_assist_interrupt() instead.
>>
>> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
>> ---
>> arch/powerpc/kernel/head_85xx.S | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/arch/powerpc/kernel/head_85xx.S b/arch/powerpc/kernel/head_85xx.S
>> index 97e9ea0c7297..0f1641a31250 100644
>> --- a/arch/powerpc/kernel/head_85xx.S
>> +++ b/arch/powerpc/kernel/head_85xx.S
>> @@ -395,7 +395,7 @@ interrupt_base:
>> #ifdef CONFIG_PPC_FPU
>> FP_UNAVAILABLE_EXCEPTION
>> #else
>> - EXCEPTION(0x0800, FP_UNAVAIL, FloatingPointUnavailable, unknown_exception)
>> + EXCEPTION(0x0800, FP_UNAVAIL, FloatingPointUnavailable, emulation_assist_interrupt)
>> #endif
>>
>> /* System Call Interrupt */
>> --
>> 2.41.0
next prev parent reply other threads:[~2023-10-10 10:57 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-25 15:55 [PATCH] powerpc/85xx: Fix math emulation exception Christophe Leroy
2023-10-10 10:45 ` Michael Ellerman
2023-10-10 10:55 ` Christophe Leroy [this message]
2023-10-15 10:00 ` Michael Ellerman
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