linux-kernel - RE: [PATCH] x86/microcode/intel: Quieten down microcode updates on large systems

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Message-ID: <DF4PR84MB0169F74AA72FF7576F5CB370AB5F0@DF4PR84MB0169.NAMPRD84.PROD.OUTLOOK.COM>
Date:	Thu, 9 Jun 2016 04:34:35 +0000
From:	"Elliott, Robert (Persistent Memory)" <elliott@....com>
To:	Andi Kleen <andi@...stfloor.org>, "x86@...nel.org" <x86@...nel.org>
CC:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Andi Kleen <ak@...ux.intel.com>
Subject: RE: [PATCH] x86/microcode/intel: Quieten down microcode updates on
 large systems



> -----Original Message-----
> From: linux-kernel-owner@...r.kernel.org [mailto:linux-kernel-
> owner@...r.kernel.org] On Behalf Of Andi Kleen
> Sent: Tuesday, May 31, 2016 4:23 PM
> To: x86@...nel.org
> Cc: linux-kernel@...r.kernel.org; Andi Kleen <ak@...ux.intel.com>
> Subject: [PATCH] x86/microcode/intel: Quieten down microcode updates
> on large systems
...
> diff --git a/arch/x86/kernel/cpu/microcode/intel.c
> @@ -808,8 +809,14 @@ static int collect_cpu_info(int cpu_num, struct
> cpu_signature *csig)
>  	}
> 
>  	csig->rev = c->microcode;
> -	pr_info("CPU%d sig=0x%x, pf=0x%x, revision=0x%x\n",
> -		cpu_num, csig->sig, csig->pf, csig->rev);
> +
> +	/* No extra locking on prev, races are harmless. */
> +	if (csig->sig != prev.sig || csig->pf != prev.pf ||
> +	    csig->rev != prev.rev) {
> +		pr_info("CPU sig=0x%x, pf=0x%x, revision=0x%x\n",
> +			csig->sig, csig->pf, csig->rev);
> +		prev = *csig;
> +	}
...
> -	pr_info("CPU%d updated to revision 0x%x, date = %04x-%02x-
> %02x\n",
> -		cpu, val[1],
> -		mc->hdr.date & 0xffff,
> -		mc->hdr.date >> 24,
> -		(mc->hdr.date >> 16) & 0xff);
> +	if (val[1] != prev_rev) {
> +		pr_info("CPU updated to revision 0x%x, date = %04x-%02x-
> %02x\n",

"CPU(s)" would help convey that the messages now apply to one or 
more CPUs.