ARM: 7848/1: mcpm: Implement cpu_kill() to synchronise on powerdown
authorDave Martin <dave.martin@linaro.org>
Tue, 1 Oct 2013 18:58:17 +0000 (19:58 +0100)
committerRussell King <rmk+kernel@arm.linux.org.uk>
Tue, 29 Oct 2013 11:07:15 +0000 (11:07 +0000)
commit0de0d64675259bf21d06b18985318ffb66a5218f
tree06f797f0632d681d537e867d1e6a1bc69a9fa135
parent1e5660999aa7703654ec345caaf06b83415dbdff
ARM: 7848/1: mcpm: Implement cpu_kill() to synchronise on powerdown

CPU hotplug and kexec rely on smp_ops.cpu_kill(), which is supposed
to wait for the CPU to park or power down, and perform the last
rites (such as disabling clocks etc., where the platform doesn't do
this automatically).

kexec in particular is unsafe without performing this
synchronisation to park secondaries.  Without it, the secondaries
might not be parked when kexec trashes the kernel.

There is no generic way to do this synchronisation, so a new mcpm
platform_ops method power_down_finish() is added by this patch.

The new method is mandatory.  A platform which provides no way to
detect when CPUs are parked is likely broken.

Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
arch/arm/common/mcpm_entry.c
arch/arm/common/mcpm_platsmp.c
arch/arm/include/asm/mcpm.h