[v5,0/4] E0PD support

Message

Mark Brown Nov. 4, 2019, 7:15 p.m. UTC

This series adds support for E0PD. We enable E0PD unconditionally where
present on systems where all the CPUs in the system support E0PD and
change to not enabling KPTI by default on systems where we have enabled
E0PD. It also converts the runtime checks for use of non-global mappings
into a variable.

v5: Rebase on v5.4-rc3 (there will be conflicts in cpucaps.h) and add
    code in patch 4 to start making non-global mappings from boot if we
    know then that we will need KPTI, preserving an existing performance
    improvement.
v4: Use a variable to store our decision about using non-global mappings
    rather than rechecking constantly at runtime. I've added this as a
    separate patch mainly for bisection.
v3: Make E0PD a system wide feature.

Mark Brown (4):
  arm64: Add initial support for E0PD
  arm64: Factor out checks for KASLR in KPTI code into separate function
  arm64: Don't use KPTI where we have E0PD
  arm64: Use a variable to store non-global mappings decision

 arch/arm64/Kconfig                     | 15 ++++++
 arch/arm64/include/asm/cpucaps.h       |  3 +-
 arch/arm64/include/asm/mmu.h           | 48 ++----------------
 arch/arm64/include/asm/pgtable-hwdef.h |  2 +
 arch/arm64/include/asm/pgtable-prot.h  |  4 +-
 arch/arm64/include/asm/sysreg.h        |  1 +
 arch/arm64/kernel/cpufeature.c         | 70 ++++++++++++++++++++++++--
 arch/arm64/mm/init.c                   |  7 +++
 8 files changed, 99 insertions(+), 51 deletions(-)