arm64: Privileged Access Never using TTBR0

From:		Catalin Marinas <catalin.marinas-AT-arm.com>
To:		linux-arm-kernel-AT-lists.infradead.org
Subject:		[PATCH v3 0/7] arm64: Privileged Access Never using TTBR0_EL1 switching
Date:		Tue, 13 Sep 2016 18:46:30 +0100
Message-ID:		<1473788797-10879-1-git-send-email-catalin.marinas@arm.com>
Cc:		Will Deacon <will.deacon-AT-arm.com>, James Morse <james.morse-AT-arm.com>, Kees Cook <keescook-AT-chromium.org>, Mark Rutland <mark.rutland-AT-arm.com>, Ard Biesheuvel <ard.biesheuvel-AT-linaro.org>, AKASHI Takahiro <takahiro.akashi-AT-linaro.org>, kernel-hardening-AT-lists.openwall.com

This is the third version of the arm64 PAN emulation using TTBR0_EL1
switching. The series has not yet included the alternative nop patches
from Mark Rutland, nor the empty_zero_page from Ard B. This will be done
in a subsequent version once 4.9-rc1 is out (which will include Mark's
alternative nop patches).

Changes since v2:

- efi_set_pgd() reworked to update the saved ttbr0 during run-time
  services as this value is used during exception return

- uaccess_(enable|disable) C macros no longer take an 'alt' parameter
  Instead, uaccess_(enable|disable)_not_uao are introduced for the case
  where hardware PAN switching is not required when UAO is present

- post_ttbr0_update_workaround macro no longer takes a 'ret' parameter

- system_supports_ttbr0_pan renamed to system_uses_ttbr0_pan

- init_thread_info.ttbr0 moved towards the end of the setup_arch()
  function and comment updated

- vmlinux.lds.S fixed to use RESERVED_TTBR0_SIZE

- Config option changed to ARM64_SW_TTBR0_PAN

- Some comment clean-ups and commit log updates

Catalin Marinas (7):
  arm64: Factor out PAN enabling/disabling into separate uaccess_*
    macros
  arm64: Factor out TTBR0_EL1 post-update workaround into a specific asm
    macro
  arm64: Introduce uaccess_{disable,enable} functionality based on
    TTBR0_EL1
  arm64: Disable TTBR0_EL1 during normal kernel execution
  arm64: Handle faults caused by inadvertent user access with PAN
    enabled
  arm64: xen: Enable user access before a privcmd hvc call
  arm64: Enable CONFIG_ARM64_SW_TTBR0_PAN

The patches are also available on this branch:

  git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux ttbr0-pan

Thanks for reviewing/testing.

 arch/arm64/Kconfig                      |   8 ++
 arch/arm64/include/asm/assembler.h      |  33 +++++++
 arch/arm64/include/asm/cpufeature.h     |   6 ++
 arch/arm64/include/asm/efi.h            |  26 ++++-
 arch/arm64/include/asm/futex.h          |  14 +--
 arch/arm64/include/asm/kernel-pgtable.h |   7 ++
 arch/arm64/include/asm/mmu_context.h    |  51 +++++++---
 arch/arm64/include/asm/ptrace.h         |   2 +
 arch/arm64/include/asm/thread_info.h    |   3 +
 arch/arm64/include/asm/uaccess.h        | 163 ++++++++++++++++++++++++++++++--
 arch/arm64/kernel/armv8_deprecated.c    |  10 +-
 arch/arm64/kernel/asm-offsets.c         |   3 +
 arch/arm64/kernel/cpufeature.c          |   1 +
 arch/arm64/kernel/entry.S               |  71 +++++++++++++-
 arch/arm64/kernel/head.S                |   6 +-
 arch/arm64/kernel/setup.c               |   9 ++
 arch/arm64/kernel/vmlinux.lds.S         |   5 +
 arch/arm64/lib/clear_user.S             |   8 +-
 arch/arm64/lib/copy_from_user.S         |   8 +-
 arch/arm64/lib/copy_in_user.S           |   8 +-
 arch/arm64/lib/copy_to_user.S           |   8 +-
 arch/arm64/mm/context.c                 |   7 +-
 arch/arm64/mm/fault.c                   |  22 +++--
 arch/arm64/mm/proc.S                    |  11 +--
 arch/arm64/xen/hypercall.S              |  19 ++++
 25 files changed, 428 insertions(+), 81 deletions(-)

arm64: Privileged Access Never using TTBR0_EL1 switching