linux-kernel - Re: [PATCH] perf, x86: Disable perf if the BIOS got its grubby paws on the PMU

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Date:	Tue, 7 Sep 2010 18:51:58 +0200
From:	Robert Richter <robert.richter@....com>
To:	Peter Zijlstra <peterz@...radead.org>
CC:	Matt Domsch <Matt_Domsch@...l.com>,
	Arjan van de Ven <arjan@...ux.intel.com>,
	Ingo Molnar <mingo@...e.hu>,
	Stephane Eranian <eranian@...gle.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	LKML <linux-kernel@...r.kernel.org>,
	"H. Peter Anvin" <hpa@...ux.kernel.org>
Subject: Re: [PATCH] perf, x86: Disable perf if the BIOS got its grubby
 paws on the PMU

On 07.09.10 17:15:41, Robert Richter wrote:
> > > > On 9/3/2010 2:13 AM, Peter Zijlstra wrote:
> > > > >+static void print_BIOS_fail(void)
> > > > >+{
> > > > >+	printk(KERN_ERR "\n");
> > > > >+	printk(KERN_ERR "=============================================\n");
> > > > >+	printk(KERN_ERR "It appears the BIOS is actively using the PMU\n");
> > > > >+	printk(KERN_ERR "this avoids Linux from using it, please de-  \n");
> > > > >+	printk(KERN_ERR "activate this BIOS feature or request a BIOS \n");
> > > > >+	printk(KERN_ERR "update from your vendor.                     \n");
> > > > >+	printk(KERN_ERR "=============================================\n");
> 
> I would rather prefer this:
> 
>  BIOS bug, cpu 1, invalid  <register=value> ...

I got the note there is already a macro for this in kernel.h:

 #define FW_BUG          "[Firmware Bug]: "

So, we would have something like:

 [Firmware Bug]: cpu 1, invalid  <register=value> ...

in dmesg.

-Robert

> 
> ... which is a much better information on one line, explains the bug
> and is also better parsable. I intend to implement messages like
> this. So maybe we could find consensus with this or something similar.
> 
> A simple grep of dmesg will then give a list of BIOS bugs.
> 
> -Robert
> 
> -- 
> Advanced Micro Devices, Inc.
> Operating System Research Center

-- 
Advanced Micro Devices, Inc.
Operating System Research Center

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