linux-kernel - Re: [PATCH] x86: call machine_shutdown and stop all CPUs in native_machine

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Message-ID: <20081106161536.GJ5228@hmsendeavour.rdu.redhat.com>
Date:	Thu, 6 Nov 2008 11:15:36 -0500
From:	Neil Horman <nhorman@...hat.com>
To:	Ivan Vecera <ivecera@...hat.com>
Cc:	Ingo Molnar <mingo@...e.hu>, linux-kernel@...r.kernel.org,
	tglx@...utronix.de, mingo@...hat.com, hpa@...or.com,
	nhorman@...hat.com, jmarchan@...hat.com
Subject: Re: [PATCH] x86: call machine_shutdown and stop all CPUs in	native_machine_halt

On Thu, Nov 06, 2008 at 05:10:01PM +0100, Ivan Vecera wrote:
> Any comments?
> 
> Ivan
> 
Acked-by: Neil Horman <nhorman@...driver.com>

> ---
> 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 (;;);
> > +}
> > +
> >  static void do_nothing(void *unused)
> >  {
> >  }
> > diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
> > index f4c93f1..3113d9e 100644
> > --- a/arch/x86/kernel/reboot.c
> > +++ b/arch/x86/kernel/reboot.c
> > @@ -465,6 +465,11 @@ static void native_machine_restart(char *__unused)
> >  
> >  static void native_machine_halt(void)
> >  {
> > +	/* stop other cpus and apics */
> > +	machine_shutdown();
> > +
> > +	/* stop this cpu */
> > +	stop_this_cpu(NULL);
> >  }
> >  
> >  static void native_machine_power_off(void)
> > diff --git a/arch/x86/kernel/smp.c b/arch/x86/kernel/smp.c
> > index 18f9b19..3f92b13 100644
> > --- a/arch/x86/kernel/smp.c
> > +++ b/arch/x86/kernel/smp.c
> > @@ -140,19 +140,6 @@ void native_send_call_func_ipi(cpumask_t mask)
> >  		send_IPI_mask(mask, CALL_FUNCTION_VECTOR);
> >  }
> >  
> > -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.
> >   */
> > diff --git a/include/asm-x86/system.h b/include/asm-x86/system.h
> > index b20c894..17ac753 100644
> > --- a/include/asm-x86/system.h
> > +++ b/include/asm-x86/system.h
> > @@ -314,6 +314,8 @@ extern void free_init_pages(char *what, unsigned long begin, unsigned long end);
> >  
> >  void default_idle(void);
> >  
> > +void stop_this_cpu(void *dummy);
> > +
> >  /*
> >   * Force strict CPU ordering.
> >   * And yes, this is required on UP too when we're talking
> 

-- 
/***************************************************
 *Neil Horman
 *Senior Software Engineer
 *Red Hat, Inc.
 *nhorman@...hat.com
 *gpg keyid: 1024D / 0x92A74FA1
 *http://pgp.mit.edu
 ***************************************************/
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