linux-kernel - Re: MCE, AMD: Hide smp-only code around CONFIG

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Message-ID: <20120207095746.GH15359@elte.hu>
Date:	Tue, 7 Feb 2012 10:57:46 +0100
From:	Ingo Molnar <mingo@...e.hu>
To:	Borislav Petkov <bp@...en8.de>,
	Nick Bowler <nbowler@...iptictech.com>,
	Randy Dunlap <rdunlap@...otime.net>,
	"H. Peter Anvin" <hpa@...or.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	LKML <linux-kernel@...r.kernel.org>,
	Kevin Winchester <kjwinchester@...il.com>
Subject: Re: MCE, AMD: Hide smp-only code around CONFIG_SMP


* Borislav Petkov <bp@...en8.de> wrote:

> On Thu, Feb 02, 2012 at 09:24:28PM +0100, Borislav Petkov wrote:
> > > Is this feature truly irrelevant on UP systems?  I ask because I've
> > > always enabled this option on my UP AMD systems in the past...
> > 
> > No, you're right. Thanks for the suggestion. Scratch that version, I'll
> > think of a better fix.
> 
> Ok, I think I got it, pls take a look and scream if something's amiss.
> 
> @Randy: it builds fine with your randconfig and with mine default one;
> I'd appreciate if you could run it too, just in case.
> 
> Thanks.
> 
> --
> From: Borislav Petkov <bp@...en8.de>
> Date: Fri, 3 Feb 2012 18:07:54 +0100
> Subject: [PATCH] MCE, AMD: Hide smp-only code around CONFIG_SMP
> 
> 141168c36cde ("x86: Simplify code by removing a !SMP #ifdefs from
> 'struct cpuinfo_x86'") removed a bunch of CONFIG_SMP ifdefs around code
> touching struct cpuinfo_x86 members but also caused the following build
> error with Randy's randconfigs:
> 
> mce_amd.c:(.cpuinit.text+0x4723): undefined reference to `cpu_llc_shared_map'
> 
> Restore the #ifdef in threshold_create_bank() which creates symlinks on
> the non-BSP CPUs.
> 
> Cc: Kevin Winchester <kjwinchester@...il.com>
> Cc: Ingo Molnar <mingo@...e.hu>
> Cc: Randy Dunlap <rdunlap@...otime.net>
> Link: http://lkml.kernel.org/r/4F298A6C.6010101@xenotime.net
> Signed-off-by: Borislav Petkov <bp@...en8.de>
> ---
>  arch/x86/kernel/cpu/mcheck/mce_amd.c |    2 ++
>  1 files changed, 2 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/x86/kernel/cpu/mcheck/mce_amd.c b/arch/x86/kernel/cpu/mcheck/mce_amd.c
> index 786e76a..e4eeaaf 100644
> --- a/arch/x86/kernel/cpu/mcheck/mce_amd.c
> +++ b/arch/x86/kernel/cpu/mcheck/mce_amd.c
> @@ -528,6 +528,7 @@ static __cpuinit int threshold_create_bank(unsigned int cpu, unsigned int bank)
>  
>  	sprintf(name, "threshold_bank%i", bank);
>  
> +#ifdef CONFIG_SMP
>  	if (cpu_data(cpu).cpu_core_id && shared_bank[bank]) {	/* symlink */
>  		i = cpumask_first(cpu_llc_shared_mask(cpu));

Could we please just define an obvious cpu_llc_shared_mask on UP 
(one bit long and set to 1) and not reintroduce the ugly
#ifdef CONFIG_SMP?

Thanks,

	Ingo
--
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