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authorStephen Warren <swarren@nvidia.com>2013-06-14 16:14:14 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2013-06-17 21:35:25 +0100
commit19ab428f4b7988ef3ac727c680efc193ef53ce14 (patch)
tree7cdce88e40ca449db2fea719b88a423f884e1157 /arch/arm/Kconfig
parent69f91ff8c93c778cb65b71d9b2d95ff62956354f (diff)
ARM: 7759/1: decouple CPU offlining from reboot/shutdown
Add comments to machine_shutdown()/halt()/power_off()/restart() that describe their purpose and/or requirements re: CPUs being active/not. In machine_shutdown(), replace the call to smp_send_stop() with a call to disable_nonboot_cpus(). This completely disables all but one CPU, thus satisfying the requirement that only a single CPU be active for kexec. Adjust Kconfig dependencies for this change. In machine_halt()/power_off()/restart(), call smp_send_stop() directly, rather than via machine_shutdown(); these functions don't need to completely de-activate all CPUs using hotplug, but rather just quiesce them. Remove smp_kill_cpus(), and its call from smp_send_stop(). smp_kill_cpus() was indirectly calling smp_ops.cpu_kill() without calling smp_ops.cpu_die() on the target CPUs first. At least some implementations of smp_ops had issues with this; it caused cpu_kill() to hang on Tegra, for example. Since smp_send_stop() is only used for shutdown, halt, and power-off, there is no need to attempt any kind of CPU hotplug here. Adjust Kconfig to reflect that machine_shutdown() (and hence kexec) relies upon disable_nonboot_cpus(). However, this alone doesn't guarantee that hotplug will work, or even that hotplug is implemented for a particular piece of HW that a multi-platform zImage runs on. Hence, add error-checking to machine_kexec() to determine whether it did work. Suggested-by: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: Stephen Warren <swarren@nvidia.com> Acked-by: Will Deacon <will.deacon@arm.com> Tested-by: Zhangfei Gao <zhangfei.gao@gmail.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/Kconfig')
-rw-r--r--arch/arm/Kconfig2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 239fa96c12bb..2651b1da1c56 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -2016,7 +2016,7 @@ config XIP_PHYS_ADDR
config KEXEC
bool "Kexec system call (EXPERIMENTAL)"
- depends on (!SMP || HOTPLUG_CPU)
+ depends on (!SMP || PM_SLEEP_SMP)
help
kexec is a system call that implements the ability to shutdown your
current kernel, and to start another kernel. It is like a reboot