diff options
| author | Stephen Warren <swarren@nvidia.com> | 2013-06-14 16:14:14 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2013-06-17 21:35:25 +0100 |
| commit | 19ab428f4b7988ef3ac727c680efc193ef53ce14 (patch) | |
| tree | 7cdce88e40ca449db2fea719b88a423f884e1157 /arch/arm/kernel/smp.c | |
| parent | 69f91ff8c93c778cb65b71d9b2d95ff62956354f (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/kernel/smp.c')
| -rw-r--r-- | arch/arm/kernel/smp.c | 13 |
1 files changed, 0 insertions, 13 deletions
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c index 550d63cef68e..5919eb451bb9 100644 --- a/arch/arm/kernel/smp.c +++ b/arch/arm/kernel/smp.c @@ -651,17 +651,6 @@ void smp_send_reschedule(int cpu) smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE); } -#ifdef CONFIG_HOTPLUG_CPU -static void smp_kill_cpus(cpumask_t *mask) -{ - unsigned int cpu; - for_each_cpu(cpu, mask) - platform_cpu_kill(cpu); -} -#else -static void smp_kill_cpus(cpumask_t *mask) { } -#endif - void smp_send_stop(void) { unsigned long timeout; @@ -679,8 +668,6 @@ void smp_send_stop(void) if (num_online_cpus() > 1) pr_warning("SMP: failed to stop secondary CPUs\n"); - - smp_kill_cpus(&mask); } /* |