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SubjectRe: [PATCH] x86: call machine_shutdown and stop all CPUs in native_machine_halt
On Thu 2008-11-06 17:10:01, Ivan Vecera wrote:
> Any comments?
>
> Ivan
>
> ---
> Ivan Vecera wrote:
> > Ingo Molnar wrote:
> >> the code in arch/x86/kernel/smp.c::stop_this_cpu() is very similar to
> >> this and could be shared. You could move the stop_this_cpu() function to
> >> arch/x86/kernel/process.c (out of smp.c), so that it can be used by
> >> reboot.c.
> >>
> > Yes, this make sense. Here is the patch.
> >
> > Ivan
> >
> > ---
> > arch/x86/kernel/process.c | 16 ++++++++++++++++
> > arch/x86/kernel/reboot.c | 5 +++++
> > arch/x86/kernel/smp.c | 13 -------------
> > include/asm-x86/system.h | 2 ++
> > 4 files changed, 23 insertions(+), 13 deletions(-)
> >
> > diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
> > index c622772..af6904e 100644
> > --- a/arch/x86/kernel/process.c
> > +++ b/arch/x86/kernel/process.c
> > @@ -8,6 +8,7 @@
> > #include <linux/pm.h>
> > #include <linux/clockchips.h>
> > #include <asm/system.h>
> > +#include <asm/apic.h>
> >
> > unsigned long idle_halt;
> > EXPORT_SYMBOL(idle_halt);
> > @@ -122,6 +123,21 @@ void default_idle(void)
> > EXPORT_SYMBOL(default_idle);
> > #endif
> >
> > +void stop_this_cpu(void *dummy)
> > +{
> > + local_irq_disable();
> > + /*
> > + * Remove this CPU:
> > + */
> > + cpu_clear(smp_processor_id(), cpu_online_map);
> > +#ifdef CONFIG_X86_LOCAL_APIC
> > + disable_local_APIC();
> > +#endif
> > + if (hlt_works(smp_processor_id()))
> > + for (;;) halt();
> > + for (;;);
> > +}

Why the new ifdef? And while we are at it, why is it neccessary to
disable APIC for stopping CPU? (comment in code would be nice)

> > -static void stop_this_cpu(void *dummy)
> > -{
> > - local_irq_disable();
> > - /*
> > - * Remove this CPU:
> > - */
> > - cpu_clear(smp_processor_id(), cpu_online_map);
> > - disable_local_APIC();
> > - if (hlt_works(smp_processor_id()))
> > - for (;;) halt();
> > - for (;;);
> > -}
> > -
> > /*
> > * this function calls the 'stop' function on all other CPUs in the system.
> > */

--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html


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