[v2,0/2] arm64: Support Enhanced PAN

Message

Vladimir Murzin Dec. 9, 2020, 1:59 p.m. UTC

Hi

ARM architecture gains support of Enhanced Privileged Access Never
(EPAN) which allows Privileged Access Never to be used with
Execute-only mappings.

As a consequence 24cecc377463 ("arm64: Revert support for execute-only
user mappings") can be revisited and re-enabled.

Changelog:

	RFC -> v1
	    - removed cap check in pte_valid_not_user (per Catalin)
	    - local_flush_tlb_all() in cpu_enable_epan() (per Catalin)
	    - reordered with CnP (per Catalin)
	    - s/HWCAP2_EPAN/HWCAP2_EXECONLY/ (per Catalin)

	v1 -> v2
	    - rebased on for-next/uaccess (for INIT_SCTLR_EL1_MMU_ON)
	    - moved EPAN enable to proc.S (via INIT_SCTLR_EL1_MMU_ON),
	      so no need in enable method from cpufeature, no need to
	      keep ordering relative to CnP (per Catalin)

Thanks!

Vladimir Murzin (2):
  arm64: Support execute-only permissions with Enhanced PAN
  arm64: Introduce HWCAPS2_EXECONLY

 arch/arm64/Kconfig                    | 17 +++++++++++++++++
 arch/arm64/include/asm/cpucaps.h      |  3 ++-
 arch/arm64/include/asm/hwcap.h        |  1 +
 arch/arm64/include/asm/pgtable-prot.h |  5 +++--
 arch/arm64/include/asm/pgtable.h      | 14 +++++++++++++-
 arch/arm64/include/asm/sysreg.h       |  4 +++-
 arch/arm64/include/uapi/asm/hwcap.h   |  1 +
 arch/arm64/kernel/cpufeature.c        | 15 +++++++++++++++
 arch/arm64/kernel/cpuinfo.c           |  1 +
 arch/arm64/mm/fault.c                 |  3 +++
 10 files changed, 59 insertions(+), 5 deletions(-)