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

Sami Tolvanen
2023-09-29T21:12:02Z

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.

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
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2.42.0.582.g8ccd20d70d-goog