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>
Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
Jordan Niethe <jniethe5@gmail.com>
Subject: Re: [PATCH] powerpc/8xx: Load modules closer to kernel text
Date: Thu, 01 Apr 2021 15:33:13 +1100 [thread overview]
Message-ID: <87ft0a1v5i.fsf@mpe.ellerman.id.au> (raw)
In-Reply-To: <e50f8127-3a87-92eb-d88a-72aa1557ffe7@csgroup.eu>
Christophe Leroy <christophe.leroy@csgroup.eu> writes:
> Le 31/03/2021 à 15:39, Michael Ellerman a écrit :
>> Christophe Leroy <christophe.leroy@csgroup.eu> writes:
>>> On the 8xx, TASK_SIZE is 0x80000000. The space between TASK_SIZE and
>>> PAGE_OFFSET is not used.
>>>
>>> Use it to load modules in order to minimise the distance between
>>> kernel text and modules and avoid trampolines in modules to access
>>> kernel functions or other module functions.
>>>
>>> Define a 16Mbytes area for modules, that's more than enough.
>>
>> 16MB seems kind of small.
>>
>> At least on 64-bit we could potentially have hundreds of MBs of modules.
>>
>
> Well, with a 16 MB kernel and 16 MB modules, my board is full :)
Heh.
> Even on the more recent board that has 128 MB, I don't expect more than a few MBs of modules in
> addition to the kernel which is approx 8M.
>
> But ok, I'll do something more generic, though it will conflict with Jordan's series.
Don't feel you have to. You're the expert on 8xx, not me.
cheers
next prev parent reply other threads:[~2021-04-01 4:34 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-29 7:07 [PATCH] powerpc/8xx: Load modules closer to kernel text Christophe Leroy
2021-03-31 13:39 ` Michael Ellerman
2021-03-31 14:12 ` Christophe Leroy
2021-04-01 4:33 ` Michael Ellerman [this message]
2021-04-01 13:43 ` Christophe Leroy
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