Re: [PATCH 0/2] riscv: Increase mmap_rnd_bits_max on Sv48/57

Kees Cook
2023-12-06T20:28:55Z

On Wed, Dec 06, 2023 at 05:14:26AM -0800, Palmer Dabbelt wrote:
> On Fri, 29 Sep 2023 14:11:56 PDT (-0700), samitolvanen@google.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@rivosinc.com>
> Acked-by: Palmer Dabbelt <palmer@rivosinc.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