linux-kernel - Re: [PATCH 2/2] x86, amd-ucode: Remove needless log messages

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Date:	Mon, 9 Nov 2009 14:35:15 +0100
From:	Andreas Herrmann <herrmann.der.user@...glemail.com>
To:	Ingo Molnar <mingo@...e.hu>
Cc:	Thomas Gleixner <tglx@...utronix.de>,
	"H. Peter Anvin" <hpa@...or.com>, linux-kernel@...r.kernel.org,
	Borislav Petkov <borislav.petkov@....com>
Subject: Re: [PATCH 2/2] x86, amd-ucode: Remove needless log messages

On Sun, Nov 08, 2009 at 03:57:48PM +0100, Ingo Molnar wrote:
> 
> * Andreas Herrmann <herrmann.der.user@...glemail.com> wrote:

 [...]

> > -	if (mc_header->processor_rev_id != equiv_cpu_id) {
> > -		printk(KERN_ERR	"microcode: CPU%d: patch mismatch "
> > -		       "(processor_rev_id: %x, equiv_cpu_id: %x)\n",
> > -		       cpu, mc_header->processor_rev_id, equiv_cpu_id);
> > +	if (mc_header->processor_rev_id != equiv_cpu_id)
> >  		return 0;
> > -	}
> >  
> >  	/* ucode might be chipset specific -- currently we don't support this */
> >  	if (mc_header->nb_dev_id || mc_header->sb_dev_id) {
> 
> but why remove this one? Someone tries to load a mismatching microcode 
> file, isnt that some sort of bug in user-space? (Which ought to find out 
> whether it has anything for the CPU at hand, and only attempt it if it's 
> matching - or so.)

The ucode file that we provide contains many ucode patches -- its a
"container" file providing patches for several CPUs. Of course this
means that there are patches in the file which are not meant for that
CPU -- that is no error case but rather normal.

> maybe it's not a KERN_ERR but KERN_INFO, but still.

KERN_DEBUG at the most. It's simple as that: if the CPU has same
PATCH_LEVEL before and after microcode.ko tried to update the ucode,
there either was no ucode-file available or it just didn't contain a
newer ucode version for this CPU.

Andreas
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