[PATCH v2 0/6] An alternative series for asymmetric AArch32 systems

[Will Deacon]

Hello again,

This is version two of the ravingly popular series I previously posted
here:

https://lore.kernel.org/r/20201021104611.2744565-1-qais.yousef@arm.com

Changes since v1 include:

  * Fix setting of compat hwcaps
  * Simplify sysfs code to use DEVICE_ATTR_RO()
  * Allow onlining of late CPUs in face of mismatch
  * Use a static key in the context-switch path
  * Avoid printing that we detected 32-bit EL0 support when we didn't

This has unfortunately introduced more complexity than I would've liked,
but it also seems to be free of any rough edges.

I haven't yet tackled the execve() problem raised by Suren. I've got some
local hacks, but nothing I'm happy with yet. They will come as follow-up
patches in any case.

As before, I don't think we should merge this stuff until we've figured
out what's going on in Android, but hopefully we can reach some agreement
on the basics before then.

Cheers,

Will

Cc: Catalin Marinas <catalin.marinas at arm.com>
Cc: Marc Zyngier <maz at kernel.org>
Cc: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
Cc: Peter Zijlstra <peterz at infradead.org>
Cc: Morten Rasmussen <morten.rasmussen at arm.com>
Cc: Qais Yousef <qais.yousef at arm.com>
Cc: Suren Baghdasaryan <surenb at google.com>
Cc: Quentin Perret <qperret at google.com>
Cc: kernel-team at android.com

--->8

Will Deacon (6):
  arm64: cpuinfo: Split AArch32 registers out into a separate struct
  arm64: Allow mismatched 32-bit EL0 support
  KVM: arm64: Kill 32-bit vCPUs on systems with mismatched EL0 support
  arm64: Kill 32-bit applications scheduled on 64-bit-only CPUs
  arm64: Advertise CPUs capable of running 32-bit applications in sysfs
  arm64: Hook up cmdline parameter to allow mismatched 32-bit EL0

 .../ABI/testing/sysfs-devices-system-cpu      |   9 +
 .../admin-guide/kernel-parameters.txt         |   7 +
 arch/arm64/include/asm/cpu.h                  |  44 ++--
 arch/arm64/include/asm/cpucaps.h              |   2 +-
 arch/arm64/include/asm/cpufeature.h           |   8 +-
 arch/arm64/kernel/cpufeature.c                | 198 ++++++++++++++----
 arch/arm64/kernel/cpuinfo.c                   |  53 ++---
 arch/arm64/kernel/process.c                   |  19 +-
 arch/arm64/kernel/signal.c                    |  26 +++
 arch/arm64/kvm/arm.c                          |  11 +-
 10 files changed, 288 insertions(+), 89 deletions(-)

-- 
2.29.2.222.g5d2a92d10f8-goog