Mitigations against spectre-v1 in the arm64 Linux kernel [LWN.net]

From:		Will Deacon <will.deacon-AT-arm.com>
To:		linux-arm-kernel-AT-lists.infradead.org
Subject:		[PATCH 0/9] Mitigations against spectre-v1 in the arm64 Linux kernel
Date:		Mon, 5 Feb 2018 15:34:15 +0000
Message-ID:		<1517844864-15887-1-git-send-email-will.deacon@arm.com>
Cc:		mark.rutland-AT-arm.com, keescook-AT-chromium.org, catalin.marinas-AT-arm.com, Will Deacon <will.deacon-AT-arm.com>, dan.j.williams-AT-intel.com, robin.murphy-AT-arm.com

Hi all,

This series implements some mitigations against spectre-v1 for arm64. It
broadly follows the work that has been done for x86, by implementing:

  * A back-end version of array_index_mask_nospec() to suppress any
    compiler optimisations that could introduce unwanted speculative
    paths

  * Masking of the syscall number to restrict speculation through the
    syscall table

  * Masking of __user pointers prior to deference in uaccess routines

The latter introduces complications in access_ok and set_fs which are
also handled in this series.

Cheers,

Will

--->8

Robin Murphy (3):
  arm64: Implement array_index_mask_nospec()
  arm64: Make USER_DS an inclusive limit
  arm64: Use pointer masking to limit uaccess speculation

Will Deacon (6):
  arm64: barrier: Add CSDB macros to control data-value prediction
  arm64: entry: Ensure branch through syscall table is bounded under
    speculation
  arm64: uaccess: Prevent speculative use of the current addr_limit
  arm64: uaccess: Don't bother eliding access_ok checks in
    __{get,put}_user
  arm64: uaccess: Mask __user pointers for __arch_{clear,copy_*}_user
  arm64: futex: Mask __user pointers prior to dereference

 arch/arm64/include/asm/assembler.h |  18 +++++
 arch/arm64/include/asm/barrier.h   |  22 ++++++
 arch/arm64/include/asm/futex.h     |   9 ++-
 arch/arm64/include/asm/processor.h |   3 +
 arch/arm64/include/asm/uaccess.h   | 155 +++++++++++++++++++++++++------------
 arch/arm64/kernel/arm64ksyms.c     |   4 +-
 arch/arm64/kernel/entry.S          |   6 +-
 arch/arm64/lib/clear_user.S        |   6 +-
 arch/arm64/lib/copy_in_user.S      |   5 +-
 arch/arm64/mm/fault.c              |   4 +-
 10 files changed, 170 insertions(+), 62 deletions(-)

-- 
2.1.4