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

[Palmer Dabbelt]

On Fri, 29 Sep 2023 14:11:56 PDT (-0700), samitolvanen at 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 at rivosinc.com>
Acked-by: Palmer Dabbelt <palmer at rivosinc.com>

in case someone else wants to take it, but I'm OK taking that MM patch 
with Kees' review.

>
> Sami
>
>  [1] https://github.com/google/android-riscv64/issues/1
>
>
> Sami Tolvanen (2):
>   mm: Change mmap_rnd_bits_max to __ro_after_init
>   riscv: mm: Update mmap_rnd_bits_max
>
>  arch/riscv/mm/init.c | 6 ++++++
>  include/linux/mm.h   | 2 +-
>  mm/mmap.c            | 2 +-
>  3 files changed, 8 insertions(+), 2 deletions(-)
>
>
> base-commit: 6465e260f48790807eef06b583b38ca9789b6072