linux-kernel - Re: [PATCH 0/2] riscv: Increase mmap_rnd_bits

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Message-ID: <202312061228.B953DE8CA@keescook>
Date:   Wed, 6 Dec 2023 12:28:50 -0800
From:   Kees Cook <keescook@...omium.org>
To:     Palmer Dabbelt <palmer@...belt.com>
Cc:     samitolvanen@...gle.com, Paul Walmsley <paul.walmsley@...ive.com>,
        aou@...s.berkeley.edu, akpm@...ux-foundation.org,
        linux-mm@...ck.org, linux-riscv@...ts.infradead.org,
        llvm@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 0/2] riscv: Increase mmap_rnd_bits_max on Sv48/57

On Wed, Dec 06, 2023 at 05:14:26AM -0800, Palmer Dabbelt wrote:
> On Fri, 29 Sep 2023 14:11:56 PDT (-0700), samitolvanen@...gle.com wrote:
> > Hi all,
> > 
> > We noticed that 64-bit RISC-V kernels limit mmap_rnd_bits to 24
> > even if the hardware supports a larger virtual address space size
> > [1]. These two patches allow mmap_rnd_bits_max to be changed during
> > init, and bumps up the maximum randomness if we end up setting up
> > 4/5-level paging at boot.
> 
> Sorry for missing this, I'm just poking through old stuff in patchwork.  As
> far as I can tell this is still relevant, the discussions are just on the
> mmap() bits (but we'd already screwed that one up and have since fixed it).
> 
> So
> 
> Reviewed-by: Palmer Dabbelt <palmer@...osinc.com>
> Acked-by: Palmer Dabbelt <palmer@...osinc.com>
> 
> in case someone else wants to take it, but I'm OK taking that MM patch with
> Kees' review.

Yes, thanks! Please do. I already +1ed it:
https://lore.kernel.org/all/202309291454.436E19663@keescook

-Kees

-- 
Kees Cook