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* [PATCH 2/5] Use the APIC to determine the hardware processor id - i386
@ 2007-03-01  7:16 Fernando Luis Vázquez Cao
  2007-03-01  7:59 ` [Fastboot] " Vivek Goyal
  0 siblings, 1 reply; 3+ messages in thread
From: Fernando Luis Vázquez Cao @ 2007-03-01  7:16 UTC (permalink / raw)
  To: Linux Kernel Mailing List; +Cc: fastboot, ebiederm, ak, akpm, judith

Use the APIC to determine the hardware processor id when APIC support
has been selected, independently of whether CONFIG_SMP is set or not.

Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
---

diff -urNp linux-2.6.21-rc2/include/asm-i386/smp.h linux-2.6.21-rc2-hwcpuid/include/asm-i386/smp.h
--- linux-2.6.21-rc2/include/asm-i386/smp.h	2007-03-01 14:02:21.000000000 +0900
+++ linux-2.6.21-rc2-hwcpuid/include/asm-i386/smp.h	2007-03-01 14:08:50.000000000 +0900
@@ -74,20 +74,6 @@ static inline int num_booting_cpus(void)
 	return cpus_weight(cpu_callout_map);
 }
 
-#ifdef CONFIG_X86_LOCAL_APIC
-
-#ifdef APIC_DEFINITION
-extern int hard_smp_processor_id(void);
-#else
-#include <mach_apicdef.h>
-static inline int hard_smp_processor_id(void)
-{
-	/* we don't want to mark this access volatile - bad code generation */
-	return GET_APIC_ID(*(unsigned long *)(APIC_BASE+APIC_ID));
-}
-#endif
-#endif
-
 extern int safe_smp_processor_id(void);
 extern int __cpu_disable(void);
 extern void __cpu_die(unsigned int cpu);
@@ -102,10 +88,23 @@ extern unsigned int num_processors;
 
 #define NO_PROC_ID		0xFF		/* No processor magic marker */
 
-#endif
+#endif /* CONFIG_SMP */
 
 #ifndef __ASSEMBLY__
 
+#ifdef CONFIG_X86_LOCAL_APIC
+#ifdef APIC_DEFINITION
+extern int hard_smp_processor_id(void);
+#else
+#include <mach_apicdef.h>
+static inline int hard_smp_processor_id(void)
+{
+	/* we don't want to mark this access volatile - bad code generation */
+	return GET_APIC_ID(*(unsigned long *)(APIC_BASE+APIC_ID));
+}
+#endif /* APIC_DEFINITION */
+#endif /* CONFIG_X86_LOCAL_APIC */
+
 extern u8 apicid_2_node[];
 
 #ifdef CONFIG_X86_LOCAL_APIC



^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [Fastboot] [PATCH 2/5] Use the APIC to determine the hardware processor id - i386
  2007-03-01  7:16 [PATCH 2/5] Use the APIC to determine the hardware processor id - i386 Fernando Luis Vázquez Cao
@ 2007-03-01  7:59 ` Vivek Goyal
  2007-03-01  8:17   ` Fernando Luis Vázquez Cao
  0 siblings, 1 reply; 3+ messages in thread
From: Vivek Goyal @ 2007-03-01  7:59 UTC (permalink / raw)
  To: Fernando Luis Vázquez Cao
  Cc: Linux Kernel Mailing List, akpm, judith, fastboot, ebiederm, ak

On Thu, Mar 01, 2007 at 04:16:59PM +0900, Fernando Luis Vázquez Cao wrote:
> Use the APIC to determine the hardware processor id when APIC support
> has been selected, independently of whether CONFIG_SMP is set or not.
> 
> Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
> ---
> 
> diff -urNp linux-2.6.21-rc2/include/asm-i386/smp.h linux-2.6.21-rc2-hwcpuid/include/asm-i386/smp.h
> --- linux-2.6.21-rc2/include/asm-i386/smp.h	2007-03-01 14:02:21.000000000 +0900
> +++ linux-2.6.21-rc2-hwcpuid/include/asm-i386/smp.h	2007-03-01 14:08:50.000000000 +0900
> @@ -74,20 +74,6 @@ static inline int num_booting_cpus(void)
>  	return cpus_weight(cpu_callout_map);
>  }
>  
> -#ifdef CONFIG_X86_LOCAL_APIC
> -
> -#ifdef APIC_DEFINITION
> -extern int hard_smp_processor_id(void);
> -#else
> -#include <mach_apicdef.h>
> -static inline int hard_smp_processor_id(void)
> -{
> -	/* we don't want to mark this access volatile - bad code generation */
> -	return GET_APIC_ID(*(unsigned long *)(APIC_BASE+APIC_ID));
> -}
> -#endif
> -#endif
> -
>  extern int safe_smp_processor_id(void);
>  extern int __cpu_disable(void);
>  extern void __cpu_die(unsigned int cpu);
> @@ -102,10 +88,23 @@ extern unsigned int num_processors;
>  
>  #define NO_PROC_ID		0xFF		/* No processor magic marker */
>  
> -#endif
> +#endif /* CONFIG_SMP */
>  
>  #ifndef __ASSEMBLY__
>  
> +#ifdef CONFIG_X86_LOCAL_APIC
> +#ifdef APIC_DEFINITION
> +extern int hard_smp_processor_id(void);
> +#else
> +#include <mach_apicdef.h>
> +static inline int hard_smp_processor_id(void)
> +{
> +	/* we don't want to mark this access volatile - bad code generation */
> +	return GET_APIC_ID(*(unsigned long *)(APIC_BASE+APIC_ID));
> +}
> +#endif /* APIC_DEFINITION */
> +#endif /* CONFIG_X86_LOCAL_APIC */
> +

I think compilation will fail if CONFIG_X86_LOCAL_APIC=n and I build a UP
kernel? There is no definition of hard_smp_processor_id in that case.

Otherwise, as a concept it seems to make sense that hard_smp_processor_id()
is not necessarily zero on UP systems.

Thanks
Vivek

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [Fastboot] [PATCH 2/5] Use the APIC to determine the hardware processor id - i386
  2007-03-01  7:59 ` [Fastboot] " Vivek Goyal
@ 2007-03-01  8:17   ` Fernando Luis Vázquez Cao
  0 siblings, 0 replies; 3+ messages in thread
From: Fernando Luis Vázquez Cao @ 2007-03-01  8:17 UTC (permalink / raw)
  To: vgoyal; +Cc: Linux Kernel Mailing List, akpm, judith, fastboot, ebiederm, ak

On Thu, 2007-03-01 at 13:29 +0530, Vivek Goyal wrote:
> On Thu, Mar 01, 2007 at 04:16:59PM +0900, Fernando Luis Vázquez Cao wrote:
> > Use the APIC to determine the hardware processor id when APIC support
> > has been selected, independently of whether CONFIG_SMP is set or not.
> > 
> > Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
> > ---
> > 
> > diff -urNp linux-2.6.21-rc2/include/asm-i386/smp.h linux-2.6.21-rc2-hwcpuid/include/asm-i386/smp.h
> > --- linux-2.6.21-rc2/include/asm-i386/smp.h	2007-03-01 14:02:21.000000000 +0900
> > +++ linux-2.6.21-rc2-hwcpuid/include/asm-i386/smp.h	2007-03-01 14:08:50.000000000 +0900
> > @@ -74,20 +74,6 @@ static inline int num_booting_cpus(void)
> >  	return cpus_weight(cpu_callout_map);
> >  }
> >  
> > -#ifdef CONFIG_X86_LOCAL_APIC
> > -
> > -#ifdef APIC_DEFINITION
> > -extern int hard_smp_processor_id(void);
> > -#else
> > -#include <mach_apicdef.h>
> > -static inline int hard_smp_processor_id(void)
> > -{
> > -	/* we don't want to mark this access volatile - bad code generation */
> > -	return GET_APIC_ID(*(unsigned long *)(APIC_BASE+APIC_ID));
> > -}
> > -#endif
> > -#endif
> > -
> >  extern int safe_smp_processor_id(void);
> >  extern int __cpu_disable(void);
> >  extern void __cpu_die(unsigned int cpu);
> > @@ -102,10 +88,23 @@ extern unsigned int num_processors;
> >  
> >  #define NO_PROC_ID		0xFF		/* No processor magic marker */
> >  
> > -#endif
> > +#endif /* CONFIG_SMP */
> >  
> >  #ifndef __ASSEMBLY__
> >  
> > +#ifdef CONFIG_X86_LOCAL_APIC
> > +#ifdef APIC_DEFINITION
> > +extern int hard_smp_processor_id(void);
> > +#else
> > +#include <mach_apicdef.h>
> > +static inline int hard_smp_processor_id(void)
> > +{
> > +	/* we don't want to mark this access volatile - bad code generation */
> > +	return GET_APIC_ID(*(unsigned long *)(APIC_BASE+APIC_ID));
> > +}
> > +#endif /* APIC_DEFINITION */
> > +#endif /* CONFIG_X86_LOCAL_APIC */
> > +
> 
> I think compilation will fail if CONFIG_X86_LOCAL_APIC=n and I build a UP
> kernel? There is no definition of hard_smp_processor_id in that case.
Hi Vivek,

Thank you for the feedback.

I tested that combination and it compiled properly. The reason is that
hard_smp_processor_id is not used anywhere in the kernel when
CONFIG_X86_LOCAL_APIC=n and CONFIG_SMP=n.

I tested all the combinations (including voyager) and everything seems
to work as expected.

Regards,

Fernando

> Otherwise, as a concept it seems to make sense that hard_smp_processor_id()
> is not necessarily zero on UP systems.
> 
> Thanks
> Vivek


^ permalink raw reply	[flat|nested] 3+ messages in thread

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2007-03-01  7:16 [PATCH 2/5] Use the APIC to determine the hardware processor id - i386 Fernando Luis Vázquez Cao
2007-03-01  7:59 ` [Fastboot] " Vivek Goyal
2007-03-01  8:17   ` Fernando Luis Vázquez Cao

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