On 05/21/2018 04:42 AM, Russell King - ARM Linux wrote:

This is the second posting - the original cover note is below.  Comments
from previous series addresesd:
- Drop R7 and R8 changes.
- Remove "PSCI" from the hypervisor version of the workaround.

 arch/arm/include/asm/bugs.h        |   6 +-
 arch/arm/include/asm/cp15.h        |   3 +
 arch/arm/include/asm/cputype.h     |   5 ++
 arch/arm/include/asm/kvm_asm.h     |   2 -
 arch/arm/include/asm/kvm_host.h    |  14 +++-
 arch/arm/include/asm/kvm_mmu.h     |  23 +++++-
 arch/arm/include/asm/proc-fns.h    |   4 +
 arch/arm/include/asm/system_misc.h |   8 ++
 arch/arm/kernel/Makefile           |   1 +
 arch/arm/kernel/bugs.c             |  18 +++++
 arch/arm/kernel/smp.c              |   4 +
 arch/arm/kernel/suspend.c          |   2 +
 arch/arm/kvm/hyp/hyp-entry.S       | 108 +++++++++++++++++++++++++-
 arch/arm/mm/Kconfig                |  23 ++++++
 arch/arm/mm/Makefile               |   2 +-
 arch/arm/mm/fault.c                |   3 +
 arch/arm/mm/proc-macros.S          |   3 +-
 arch/arm/mm/proc-v7-2level.S       |   6 --
 arch/arm/mm/proc-v7-bugs.c         | 130 +++++++++++++++++++++++++++++++
 arch/arm/mm/proc-v7.S              | 154 +++++++++++++++++++++++++++++--------
 20 files changed, 469 insertions(+), 50 deletions(-)
 create mode 100644 arch/arm/kernel/bugs.c
 create mode 100644 arch/arm/mm/proc-v7-bugs.c

Since there appears to be more work needed in the PSCI/KVM changes
(patches 9 through 14), how about we go with the "bare-metal" parts:
patches 1-8 first and try to get those included ASAP?

The rationale being that a lot of affected people have Linux running on
ARMv7-A Cortex-A, typically A9, A15, Brahma-B15, and are in need of
those patches but do not necessarily require KVM fixes right now, and
even less so PSCI infrastructure to mitigate ARMv8-A running in AArch32.

In terms of backporting to -stable, and because the spectre variant 1
patches have not been submitted yet, it is not like we can lump
everything in one go anyway, so we are not making the lives of the
-stable maintainers any worse than it currently is?

Yay or nay?

On Wed, May 16, 2018 at 11:59:49AM +0100, Russell King - ARM Linux wrote:

quoted

This series addresses the Spectre variant 2 issues on ARM Cortex and
Broadcom Brahma B15 CPUs.  Due to the complexity of the bug, it is not
possible to verify that this series fixes any of the bugs, since it
has not been able to reproduce these exact scenarios using test
programs.

I believe that this covers the entire extent of the Spectre variant 2
issues, with the exception of Cortex A53 and Cortex A72 processors as
these require a substantially more complex solution (except where the
workaround is implemented in PSCI firmware.)

Spectre variant 1 is not covered by this series.

The patch series is based partly on Marc Zyngier's work from February -
two of the KVM patches are from Marc's work.

The main differences are:
- Inclusion of more processors as per current ARM Ltd security update
  documentation.
- Extension of "bugs" infrastructure to detect Cortex A8 and Cortex A15
  CPUs missing out on the IBE bit being set on (re-)entry to the kernel
  through all paths.
- Handle all suspect userspace-touching-kernelspace aborts irrespective
  of mapping type.

The first patch will trivially conflict with the Broadcom Brahma
updates already in arm-soc - it has been necessary to independently
add the ID definitions for the B15 CPU.

Having worked through this series, I'm of the opinion that the
define_processor_functions macro in proc-v7 are probably  more hassle
than they're worth - here, we don't need the global equivalent symbols,
because we never refer to them from the kernel code for any V7
processor (MULTI_CPU is always defined.)

This series is currently in my "spectre" branch (along with some
Spectre variant 1 patches.)

Please carefully review.

 arch/arm/include/asm/bugs.h        |   6 +-
 arch/arm/include/asm/cp15.h        |   3 +
 arch/arm/include/asm/cputype.h     |   5 ++
 arch/arm/include/asm/kvm_asm.h     |   2 -
 arch/arm/include/asm/kvm_host.h    |  14 +++-
 arch/arm/include/asm/kvm_mmu.h     |  23 +++++-
 arch/arm/include/asm/proc-fns.h    |   4 +
 arch/arm/include/asm/system_misc.h |   8 ++
 arch/arm/kernel/Makefile           |   1 +
 arch/arm/kernel/bugs.c             |  18 +++++
 arch/arm/kernel/smp.c              |   4 +
 arch/arm/kernel/suspend.c          |   2 +
 arch/arm/kvm/hyp/hyp-entry.S       | 108 ++++++++++++++++++++++++-
 arch/arm/mm/Kconfig                |  23 ++++++
 arch/arm/mm/Makefile               |   2 +-
 arch/arm/mm/fault.c                |   3 +
 arch/arm/mm/proc-macros.S          |   3 +-
 arch/arm/mm/proc-v7-2level.S       |   6 --
 arch/arm/mm/proc-v7-bugs.c         | 130 ++++++++++++++++++++++++++++++
 arch/arm/mm/proc-v7.S              | 158 +++++++++++++++++++++++++++++--------
 20 files changed, 471 insertions(+), 52 deletions(-)

-- 
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
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