On Tue, Mar 11, 2014 at 06:48:13PM -0500, Scott Wood wrote:
> On Fri, 2014-03-07 at 12:58 +0800, Chenhui Zhao wrote:
> > diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
> > index ac2621a..f3f4401 100644
> > --- a/arch/powerpc/kernel/smp.c
> > +++ b/arch/powerpc/kernel/smp.c
> > @@ -405,8 +405,12 @@ void generic_cpu_die(unsigned int cpu)
> >
> > for (i = 0; i < 100; i++) {
> > smp_rmb();
> > - if (per_cpu(cpu_state, cpu) == CPU_DEAD)
> > + if (per_cpu(cpu_state, cpu) == CPU_DEAD) {
> > +#ifdef CONFIG_PPC64
> > + paca[cpu].cpu_start = 0;
> > +#endif
>
> Why wasn't this needed by previous ppc64 machines?
If not clear, cpu can't start in the case of cpu hotpolug.
The function pseries_cpu_die() in arch/powerpc/platforms/pseries/hotplug-cpu.c
also clears the flag.
>
> > diff --git a/arch/powerpc/platforms/85xx/smp.c
> > b/arch/powerpc/platforms/85xx/smp.c
> > index 2e5911e..0047883 100644
> > --- a/arch/powerpc/platforms/85xx/smp.c
> > +++ b/arch/powerpc/platforms/85xx/smp.c
> > @@ -19,6 +19,7 @@
> > #include <linux/kexec.h>
> > #include <linux/highmem.h>
> > #include <linux/cpu.h>
> > +#include <linux/smp.h>
> >
> > #include <asm/machdep.h>
> > #include <asm/pgtable.h>
> > @@ -46,6 +47,17 @@ static u64 timebase;
> > static int tb_req;
> > static int tb_valid;
> >
> > +#ifdef CONFIG_PPC_E500MC
> > +/* specify the cpu PM state when cpu dies, PH15/NAP is the default */
> > +int qoriq_cpu_die_state = E500_PM_PH15;
> > +#endif
>
> static? Is there any way to modify this other than modifying source
> code?
>
> BTW, QorIQ doesn't imply an e500mc derivative.
Will support e500, but for now these code support e500mc derivative in
advance.
Supposed qoriq_cpu_die_state can be changed by platform init code
if the default value is not proper for a specific platform.
>
> > @@ -125,6 +138,34 @@ static void mpc85xx_take_timebase(void)
> > }
> >
> > #ifdef CONFIG_HOTPLUG_CPU
> > +#ifdef CONFIG_PPC_E500MC
> > +static void qoriq_cpu_die(void)
> > +{
> > + unsigned int cpu = smp_processor_id();
> > +
> > + local_irq_disable();
> > +#ifdef CONFIG_PPC64
> > + __hard_irq_disable();
> > +#endif
>
> Why this instead of one call to hard_irq_disable() (no leading
> underscores)?
>
> -Scott
hard_irq_disable() will clear soft_enabled again. local_irq_disable()
has cleared it.
Will use hard_irq_disable() to replace these lines.
local_irq_disable();
#ifdef CONFIG_PPC64
__hard_irq_disable();
#endif
-Chenhui
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