linux-kernel - Re: [PATCH] powerpc/8xx: Load modules closer to kernel text

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Message-ID: <87czvf788t.fsf@mpe.ellerman.id.au>
Date:   Thu, 01 Apr 2021 00:39:14 +1100
From:   Michael Ellerman <mpe@...erman.id.au>
To:     Christophe Leroy <christophe.leroy@...roup.eu>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>
Cc:     linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: Re: [PATCH] powerpc/8xx: Load modules closer to kernel text

Christophe Leroy <christophe.leroy@...roup.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.

cheers