[PATCH v4 00/14] An alternative series for asymmetric AArch32 systems

[Will Deacon]

Hello folks,

Here's version four of the wonderful patches I previously posted here:

  v1: https://lore.kernel.org/r/20201027215118.27003-1-will@kernel.org
  v2: https://lore.kernel.org/r/20201109213023.15092-1-will@kernel.org
  v3: https://lore.kernel.org/r/20201113093720.21106-1-will@kernel.org

and which started life as a reimplementation of some patches from Qais:

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

The aim of this series is to allow 32-bit ARM applications to run on
arm64 SoCs where not all of the CPUs support the 32-bit instruction set.
Unfortunately, such SoCs are real and will continue to be productised
over the next few years at least.

Changes in v4 include:

  * Take into account the cpuset 'allowed' mask on exec
  * Print a warning if we forcefully override the affinity, like we do
    in select_fallback_rq()
  * Rename arch_cpu_allowed_mask() to arch_task_cpu_possible_mask()
  * Added a comment to adjust_compat_task_affinity()

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: Tejun Heo <tj at kernel.org>
Cc: Li Zefan <lizefan at huawei.com>
Cc: Johannes Weiner <hannes at cmpxchg.org>
Cc: Ingo Molnar <mingo at redhat.com>
Cc: Juri Lelli <juri.lelli at redhat.com>
Cc: Vincent Guittot <vincent.guittot at linaro.org>
Cc: kernel-team at android.com

--->8

Will Deacon (14):
  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
  sched: Introduce restrict_cpus_allowed_ptr() to limit task CPU
    affinity
  arm64: exec: Adjust affinity for compat tasks with mismatched 32-bit
    EL0
  cpuset: Don't use the cpu_possible_mask as a last resort for cgroup v1
  sched: Introduce arch_task_cpu_possible_mask() to limit fallback rq
    selection
  sched: Reject CPU affinity changes based on
    arch_task_cpu_possible_mask()
  arm64: Prevent offlining first CPU with 32-bit EL0 on mismatched
    system
  arm64: Implement arch_task_cpu_possible_mask()
  arm64: Remove logic to kill 32-bit tasks on 64-bit-only cores

 .../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/include/asm/mmu_context.h          |  13 ++
 arch/arm64/kernel/cpufeature.c                | 219 ++++++++++++++----
 arch/arm64/kernel/cpuinfo.c                   |  53 +++--
 arch/arm64/kernel/process.c                   |  47 +++-
 arch/arm64/kvm/arm.c                          |  11 +-
 include/linux/sched.h                         |   1 +
 kernel/cgroup/cpuset.c                        |   6 +-
 kernel/sched/core.c                           |  90 +++++--
 13 files changed, 401 insertions(+), 109 deletions(-)

-- 
2.29.2.454.gaff20da3a2-goog