From: Christophe Leroy <christophe.leroy@c-s.fr>
To: Michael Ellerman <mpe@ellerman.id.au>,
Paul Mackerras <paulus@samba.org>,
Benjamin Herrenschmidt <benh@au1.ibm.com>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>
Subject: Re: Does SMP work at all on 40x ?
Date: Thu, 31 Jan 2019 11:53:17 +0100 [thread overview]
Message-ID: <b0a16b8f-308a-e59a-f3d9-7f7360835e86@c-s.fr> (raw)
In-Reply-To: <871s4uqskb.fsf@concordia.ellerman.id.au>
Le 30/01/2019 à 12:43, Michael Ellerman a écrit :
> Christophe Leroy <christophe.leroy@c-s.fr> writes:
>
>> In transfer_to_handler() (entry_32.S), we have:
>>
>> #if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
>> ...
>> #ifdef CONFIG_SMP
>> CURRENT_THREAD_INFO(r9, r1)
>> lwz r9,TI_CPU(r9)
>> slwi r9,r9,3
>> add r11,r11,r9
>> #endif
>> #endif
>>
>> When running this piece of code, MMU translation is off. But r9 contains
>> the virtual addr of current_thread_info, so unless I miss something,
>> this cannot work on the 40x, can it ?
>>
>> On CONFIG_BOOKE it works because phys addr = virt addr
>
> AFAIK 40x can't be SMP:
>
> config SMP
> depends on PPC_BOOK3S || PPC_BOOK3E || FSL_BOOKE || PPC_47x
>
>
> But this stuff is all before my time.
>
> The commit that added the SMP block was clearly only meant for BookE:
>
> 4eaddb4d7ec3 ("[POWERPC] Make Book-E debug handling SMP safe")
Ok, then no need to worry about it. It will implicitely get fixed with
the THREAD_INFO_IN_TASK_STRUCT series.
Christophe
next prev parent reply other threads:[~2019-01-31 10:55 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-30 7:16 Does SMP work at all on 40x ? Christophe Leroy
2019-01-30 11:43 ` Michael Ellerman
2019-01-31 10:53 ` Christophe Leroy [this message]
2019-02-01 7:42 ` Benjamin Herrenschmidt
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