linux-kernel - Re: Voyager phys_cpu_present

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Date:	Fri, 25 Apr 2008 09:50:43 -0500
From:	James Bottomley <James.Bottomley@...senPartnership.com>
To:	Ingo Molnar <mingo@...e.hu>
Cc:	Adrian Bunk <bunk@...nel.org>,
	Alexey Starikovskiy <astarikovskiy@...e.de>,
	tglx@...utronix.de, hpa@...or.com, linux-kernel@...r.kernel.org
Subject: Re: Voyager phys_cpu_present_map compile error

On Mon, 2008-04-21 at 22:14 +0200, Ingo Molnar wrote:
> * Adrian Bunk <bunk@...nel.org> wrote:
> 
> > > +#ifndef CONFIG_X86_VOYAGER
> > >  /* Bitmask of physically existing CPUs */
> > >  physid_mask_t phys_cpu_present_map;
> > > +#endif
> > >...
> > 
> > Alexey noted that phys_cpu_present_map for Voyager and !Voyager also 
> > have different types and suggested to make the Voyager one static 
> > instead (additional renaming of the Voyager one also makes sense).
> 
> yep, done by the patch below.

Actually, this isn't the right patch.  The point is not to avoid the
symbol clash, it's to let voyager identify correctly that you have a
leaking symbol.  In this case phys_cpu_present_map is exposed outside of
SMP.  The correct fix (and one which sweeps op other storage for
unnecessary symbols is this):

James

---

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index c0c68c1..d68aa53 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -12,6 +12,7 @@
 #include <asm/mpspec.h>
 #include <asm/apicdef.h>
 
+#ifdef CONIFG_X86_SMP
 unsigned int num_processors;
 unsigned disabled_cpus __cpuinitdata;
 /* Processor that is doing the boot up */
@@ -23,8 +24,9 @@ EXPORT_PER_CPU_SYMBOL(x86_cpu_to_apicid);
 
 /* Bitmask of physically existing CPUs */
 physid_mask_t phys_cpu_present_map;
+#endif
 
-#if defined(CONFIG_HAVE_SETUP_PER_CPU_AREA) && defined(CONFIG_SMP)
+#if defined(CONFIG_HAVE_SETUP_PER_CPU_AREA) && defined(CONFIG_X86_SMP)
 /*
  * Copy data used in early init routines from the initial arrays to the
  * per cpu data areas.  These arrays then become expendable and the


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