[0/4] Provide generic top-down mmap layout functions

Message

Alexandre Ghiti March 22, 2019, 7:42 a.m. UTC

This series introduces generic functions to make top-down mmap layout
easily accessible to architectures, in particular riscv which was
the initial goal of this series.
The generic implementation was taken from arm64 and used successively
by arm, mips and finally riscv.

Note that in addition the series fixes 2 issues:
- stack randomization was taken into account even if not necessary.
- [1] fixed an issue with mmap base which did not take into account
  randomization but did not report it to arm and mips, so by moving
  arm64 into a generic library, this problem is now fixed for both
  architectures.

This work is an effort to factorize architecture functions to avoid
code duplication and oversights as in [1].

[1]: https://www.mail-archive.com/[e-mail]/msg1429066.html

Alexandre Ghiti (4):
  arm64, mm: Move generic mmap layout functions to mm
  arm: Use generic mmap top-down layout
  mips: Use generic mmap top-down layout
  riscv: Make mmap allocation top-down by default

 arch/arm/include/asm/processor.h   |  2 +-
 arch/arm/mm/mmap.c                 | 52 ----------------
 arch/arm64/include/asm/processor.h |  2 +-
 arch/arm64/mm/mmap.c               | 72 ----------------------
 arch/mips/include/asm/processor.h  |  4 +-
 arch/mips/mm/mmap.c                | 57 -----------------
 arch/riscv/Kconfig                 | 12 ++++
 arch/riscv/include/asm/processor.h |  1 +
 fs/binfmt_elf.c                    | 20 ------
 include/linux/mm.h                 |  2 +
 kernel/sysctl.c                    |  6 +-
 mm/util.c                          | 99 +++++++++++++++++++++++++++++-
 12 files changed, 121 insertions(+), 208 deletions(-)