linux-kernel - Re: [PATCH] riscv: mm: Proper page permissions after initmem free

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Message-ID: <871qq5tv5u.fsf@all.your.base.are.belong.to.us>
Date:   Mon, 14 Nov 2022 16:25:49 +0100
From:   Björn Töpel <bjorn@...nel.org>
To:     Alexandre Ghiti <alex@...ti.fr>,
        Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>,
        linux-riscv@...ts.infradead.org
Cc:     Björn Töpel <bjorn@...osinc.com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] riscv: mm: Proper page permissions after initmem free

Alexandre Ghiti <alex@...ti.fr> writes:

>> +		set_kernel_memory(__init_begin, __init_end, set_memory_rw_nx);
>
>
> That's nits but for 64-bit kernels, do we really want to make the kernel 
> mapping writable? I think catching a write access here would be better 
> because IMO that should not happen.

Thanks for having a look!

Hmm, so what you're suggesting is a "set_memory_r_nx" for CONFIG_64BIT?
What do other archs do? Is it worth the extra ifdef clutter?


Björn