[PATCH v2 00/23] arm64: Implement parallel CPU onlining with PSCI v0.2+

[Will Deacon]

Hi everyone,

This is version two of the patches I previously posted here:

  https://lore.kernel.org/all/20260907164024.17164-1-will@kernel.org/

There have been quite a few changes since last time, thanks to all the
feedback from humans and robots alike. These include:

  * Added tags (but I didn't carry over Pankaj's T-b, since the series
    has changed a fair bit).

  * Fix secondary entry assembly code to handle timeouts correctly.

  * Fix stashing of MPIDR so that we don't clobber STACK_END_MAGIC.

  * Fix NULL dereference if PSCI fails to initialise.

  * Enable RCU as soon as a secondary CPU is alive.

  * Drop pointless (unreachable) optimisation to
    arch_cpuhp_sync_state_poll().

  * Include cpufeature patches from Fuad so that 'cpu_data' is populated
    with register values taking into account any cmdline overrides. This
    is necessary for correct handling of 'boot_cpu_data' later on, where
    the previous version of this series stashed a stale copy of mpamidr.

As before, the first four patches are small changes to the generic code
to make it a little more "Arm-shaped" but the rest of the series is
largely confined to the arm64 architecture and PSCI driver code.

The series is based on -rc2, as it otherwise conflicts with Fuad's GMID
fix that was recently merged upstream.

Cheers,

Will

Cc: Thomas Gleixner <tglx at kernel.org>
Cc: Ben Horgan <ben.horgan at arm.com>
Cc: Ștefania Ion <stefion at google.com>
Cc: Catalin Marinas <catalin.marinas at arm.com>
Cc: Pankaj Patil <pankaj.patil at oss.qualcomm.com>
Cc: Borislav Petkov <bp at alien8.de>
Cc: Lorenzo Pieralisi <lpieralisi at kernel.org>
Cc: Jinjie Ruan <ruanjinjie at huawei.com>
Cc: Mark Rutland <mark.rutland at arm.com>
Cc: Tarun Sahu <tarunsahu at google.com>
Cc: Fuad Tabba <fuad.tabba at linux.dev>
Cc: David Woodhouse <dwmw at amazon.co.uk>
Cc: Peter Zijlstra <peterz at infradead.org>
Cc: Marc Zyngier <maz at kernel.org>

--->8

Fuad Tabba (4):
  arm64: cpufeature: Check arm64_ftr_regs[] before the first store
  arm64: cpufeature: Add read_cpuid_with_overrides()
  arm64: cpufeature: Read MPAMIDR_EL1 in __cpuinfo_store_cpu()
  arm64: cpufeature: Store every ID register with its overrides applied

Will Deacon (19):
  cpu/hotplug: Clean up cmpxchg() logic in cpuhp_can_boot_ap()
  cpu/hotplug: Avoid trying to bring up CPUs that are already online
  cpu/hotplug: Avoid busy-polling on archs where cpu_relax() is a no-op
  cpu/hotplug: Propagate bring-up status to
    arch_cpuhp_cleanup_kick_cpu()
  arm64: smp: Tidy up smp_prepare_cpus()
  arm64: smp: Tidy up cpuinfo init and cpufeature updates
  arm64: smp: Defer update of secondary CPU capabilities
  arm64: smp: Don't bother printing the I-cache policy for each CPU
  arm64: smp: Defer RCU registration during secondary CPU bringup
  arm64: smp: Use generic HOTPLUG_CORE_SYNC_FULL machinery for CPU
    onlining
  arm64: smp: Use generic HOTPLUG_SPLIT_STARTUP machinery for CPU
    onlining
  arm64: cpu_ops: Make 'cpu_operations' pointer global instead of
    per-cpu
  arm64: cpu_ops: Introduce get_secondary_cpu_ops()
  firmware/psci: Cache PSCI v0.2+ version number to avoid redundant SMCs
  firmware/psci: Extend ->cpu_on() callback to take an additional
    argument
  arm64: cpu_ops: Expose optional argument to target cpu in ->cpu_boot()
  arm64: smp: Pass secondary CPU boot parameters via firmware if
    possible
  arm64: smp: Use generic HOTPLUG_PARALLEL machinery for CPU onlining
  arm64: smp: Harden parallel CPU bringup against broken PSCI firmware

 arch/arm/kernel/psci_smp.c                |   4 +-
 arch/arm64/Kconfig                        |   2 +-
 arch/arm64/include/asm/cpu.h              |   7 +-
 arch/arm64/include/asm/cpu_ops.h          |   7 +-
 arch/arm64/include/asm/cpufeature.h       |  11 +
 arch/arm64/include/asm/smp.h              |  40 ++-
 arch/arm64/include/asm/topology.h         |   2 +
 arch/arm64/kernel/acpi_parking_protocol.c |   3 +-
 arch/arm64/kernel/asm-offsets.c           |   1 +
 arch/arm64/kernel/cpu_ops.c               |  34 +-
 arch/arm64/kernel/cpufeature.c            | 397 +++++++++++-----------
 arch/arm64/kernel/cpuinfo.c               | 122 +++----
 arch/arm64/kernel/head.S                  |  60 +++-
 arch/arm64/kernel/psci.c                  |  14 +-
 arch/arm64/kernel/smp.c                   | 183 +++++-----
 arch/arm64/kernel/smp_spin_table.c        |   2 +-
 arch/arm64/mm/mmu.c                       |   2 +-
 arch/x86/kernel/smpboot.c                 |   4 +-
 drivers/firmware/psci/psci.c              |  27 +-
 include/linux/cpuhotplug.h                |   2 +-
 include/linux/psci.h                      |   3 +-
 include/linux/rcutree.h                   |   2 +-
 kernel/cpu.c                              |  18 +-
 23 files changed, 508 insertions(+), 439 deletions(-)

-- 
2.56.0.385.gd3acb90ef8-goog