[PATCHv4 0/2] cpu/hotplug: Keep cpu hotplug disabled until the rebooting cpu is stable

[Pingfan Liu]

For the architectures (arm/arm64/ia64/riscv), which relies on the cpu
hot-removing mechanism to implement "kexec -e", it is important to
ensure that the rebooting happens on a valid online cpu. And this logic
should have been guaranteed in migrate_to_reboot_cpu().

But the current code has either contradict (resolved by [2/2]) or
redundancy (resolved by [1/2]) about the logic.


V3 -> V4:
Fix the cpu hotplug enable before kexec-rebooting in powerpc.
Improve commit log and the code's note.

V2 -> V3:
Taking in [2/2], which also has problem with the valid rebooting
cpu. (I had sent three patches for different arches. But maybe it is
better to collapse them into one and collect acks from different arches'
maintainers )

Cc: Eric Biederman <ebiederm at xmission.com>
Cc: Peter Zijlstra <peterz at infradead.org>
Cc: Thomas Gleixner <tglx at linutronix.de>
Cc: Vincent Donnefort <vincent.donnefort at arm.com>
Cc: Ingo Molnar <mingo at kernel.org>
Cc: YueHaibing <yuehaibing at huawei.com>
Cc: Baokun Li <libaokun1 at huawei.com>
Cc: Randy Dunlap <rdunlap at infradead.org>
Cc: Valentin Schneider <valentin.schneider at arm.com>
Cc: kexec at lists.infradead.org
Cc: Geert Uytterhoeven <geert at linux-m68k.org>
Cc: Kees Cook <keescook at chromium.org>
Cc: Jens Axboe <axboe at kernel.dk>
To: linux-ia64 at vger.kernel.org
Cc: Russell King <linux at armlinux.org.uk>
Cc: Guenter Roeck <linux at roeck-us.net>

Pingfan Liu (2):
  cpu/hotplug: Keep cpu hotplug disabled until the rebooting cpu is
    stable
  cpu/hotplug: Remove the input parameter primary_cpu of
    smp_shutdown_nonboot_cpus()

 arch/arm/kernel/reboot.c          |  2 +-
 arch/arm64/kernel/process.c       |  2 +-
 arch/ia64/kernel/process.c        |  2 +-
 arch/powerpc/kexec/core_64.c      |  1 +
 arch/riscv/kernel/machine_kexec.c |  2 +-
 include/linux/cpu.h               |  4 ++--
 kernel/cpu.c                      | 14 +++++++-------
 kernel/kexec_core.c               | 11 +++++------
 8 files changed, 19 insertions(+), 19 deletions(-)

-- 
2.31.1