linux-kernel - Re: [PATCH 1/2 V2] hwmon: (coretemp) Detect the thermal sensors by CPUID

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 11 May 2010 11:41:38 +0800
From:	Huaxu Wan <huaxu.wan@...ux.intel.com>
To:	Valdis.Kletnieks@...edu
Cc:	Huaxu Wan <huaxu.wan@...ux.intel.com>,
	linux-kernel@...r.kernel.org, lm-sensors@...sensors.org,
	huaxu.wan@...el.com, Carsten Emde <Carsten.Emde@...dl.org>
Subject: Re: [PATCH 1/2 V2] hwmon: (coretemp) Detect the thermal sensors by
 CPUID

On 08:45 Mon 10 May, Valdis.Kletnieks@...edu wrote:
> On Mon, 10 May 2010 11:35:25 +0800, Huaxu Wan said:
> > -
> > -		/* check if family 6, models 0xe (Pentium M DC),
> > -		  0xf (Core 2 DC 65nm), 0x16 (Core 2 SC 65nm),
> > -		  0x17 (Penryn 45nm), 0x1a (Nehalem), 0x1c (Atom),
> > -		  0x1e (Lynnfield) */
> > -		if ((c->cpuid_level < 0) || (c->x86 != 0x6) ||
> > -		    !((c->x86_model == 0xe) || (c->x86_model == 0xf) ||
> > -			(c->x86_model == 0x16) || (c->x86_model == 0x17) ||
> > -			(c->x86_model == 0x1a) || (c->x86_model == 0x1c) ||
> > -			(c->x86_model == 0x1e))) {
> 
> So we remove something that checks the CPU level for a model we *expect*
> to find a thermal sensor, and only throws a KERN_WARNING if we're on a
> model we don't know about...
> 
> > + 		/* check if the CPU has thermal sensor */
> > + 		eax = cpuid_eax(0x06);
> > + 		if (!(eax & 0x01)) {
> > + 			struct cpuinfo_x86 *c = &cpu_data(i);
> > + 			printk(KERN_WARNING DRVNAME ": CPU (model=0x%x)"
> > + 				" has no thermal sensor!\n", c->x86_model);
> 
> And replace it with a totally unprotected check that's going to fire off
> a KERN_WARNING on every single CPU that Intel ever made that doesn't
> include a hardware thermal sensor - including all the family 0-5,
> and model < 0x0e hardware.

Oops! That's a bug. Thank you!

> 
> KERN_WARNING is for "We expected to find the hardware but it's gone off
> for a walk on us".  If you wanted to say "Hmm.. this CPU doesn't have one"
> you probably wanted KERN_DEBUG or *maybe* KERN_INFO.

I think the better one is KERN_INFO here. 

-- 
Thanks
Huaxu
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/