[PATCH RFC 0/3] arm64: Add HOTPLUG_PARALLEL support for secondary CPUs

[Jinjie Ruan]

Support for parallel secondary CPU bringup is already utilized by x86,
MIPS, and RISC-V. This patch brings this capability to the arm64
architecture.

Introduce CONFIG_PARALLEL_SMT_PRIMARY_FIRST to avoid primary SMT threads
to boot first constraint.

And Add a 'cpu' parameter to update_cpu_boot_status() to allow updating the
boot status at a per-CPU granularity during parallel bringup.

Rework the global `secondary_data` accessed during early boot into
a per-CPU array. This array maps logical CPU IDs to MPIDR_EL1 values,
enabling the early boot code in head.S to resolve each secondary CPU's
logical ID concurrently.

Jinjie Ruan (3):
  cpu/hotplug: Introduce CONFIG_PARALLEL_SMT_PRIMARY_FIRST
  arm64: smp: Pass CPU ID to update_cpu_boot_status()
  arm64: Add HOTPLUG_PARALLEL support for secondary CPUs

 arch/Kconfig                   |  4 ++++
 arch/arm64/Kconfig             |  1 +
 arch/arm64/include/asm/smp.h   | 14 +++++++++++---
 arch/arm64/kernel/cpufeature.c |  2 +-
 arch/arm64/kernel/head.S       | 23 ++++++++++++++++++++++
 arch/arm64/kernel/smp.c        | 35 ++++++++++++++++++++++++++++++----
 arch/arm64/mm/context.c        |  2 +-
 arch/mips/Kconfig              |  1 +
 arch/riscv/Kconfig             |  1 +
 arch/x86/Kconfig               |  1 +
 kernel/cpu.c                   |  6 +++++-
 11 files changed, 80 insertions(+), 10 deletions(-)

-- 
2.34.1