[RFC PATCH 0/5] arm64: initial CPU_HOTPLUG support

[Mark Rutland]

The following patches add basic CPU_HOTPLUG support to arm64, which
combined with appropriate firmware (e.g. [1]) can be used to power CPUs
up and down dynamically. From discussions at connect it seemed that
several people were interested in working in this area, so I thought I'd
make my current implementation public now that I've managed to regain
access to my inbox.

I've tested this series with the bootwrapper PSCI implementation I've
placed on linux-arm.org [1] and a modified foundation model dts with a
psci node and each CPU's enable-method set to "psci", using a shell
while repeatedly cycling all cpus off and on:

for C in $(seq 0 3); do
	./cyclichotplug.sh $C >/dev/null 2>&1 &
done

---->8----
#!/bin/sh
# cyclichotplug.sh

CPU=$1;

if [ -z "$CPU" ]; then
	printf "Usage: $0 <cpu id>\n";
	exit 1;
fi

ONLINEFILE=/sys/devices/system/cpu/cpu$CPU/online;

while true; do
	echo 0 > $ONLINEFILE;
	echo 1 > $ONLINEFILE;
done
---->8----

Patches are based on v3.10.

Thanks,
Mark.

[1] http://linux-arm.org/git?p=boot-wrapper-aarch64.git;a=shortlog;h=refs/tags/simple-psci

Mark Rutland (5):
  arm64: reorganise smp_enable_ops
  arm64: factor out spin-table boot method
  arm64: read enable-method for CPU0
  arm64: add CPU_HOTPLUG infrastructure
  arm64: add PSCI CPU_OFF-based hotplug support

 arch/arm64/Kconfig                 |    7 ++
 arch/arm64/include/asm/irq.h       |    1 +
 arch/arm64/include/asm/smp.h       |   37 +++++--
 arch/arm64/kernel/cputable.c       |    2 +-
 arch/arm64/kernel/head.S           |   12 +-
 arch/arm64/kernel/irq.c            |   61 ++++++++++
 arch/arm64/kernel/process.c        |    7 ++
 arch/arm64/kernel/smp.c            |  215 ++++++++++++++++++++++--------------
 arch/arm64/kernel/smp_psci.c       |   54 +++++++--
 arch/arm64/kernel/smp_spin_table.c |   85 +++++++++++++-
 arch/arm64/kernel/vmlinux.lds.S    |    1 -
 11 files changed, 375 insertions(+), 107 deletions(-)

-- 
1.7.9.5