lkml.org 
[lkml]   [2011]   [May]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: [PATCH 1/3] x86, intel: Output microcode revision
On Wed, May 25, 2011 at 11:05:01AM +0200, Ingo Molnar wrote:
> > Frankly, I'm not even 100% persuaded this is needed. The coretemp.c
> > jump-through-hoops to get the ucode revision is maybe the only case
> > that warrants adding that field to /proc/cpuinfo.

> I've often wondered whether the CPU involved in a particular bugreport
> has the latest microcode installed.

Ok, that's a good point, actually.

> Sure we have /sys/devices/system/cpu/cpuN/microcode/version, but
> that's both privileged to get

Not only that but you have to load the ucode driver to be able to read
it. /proc/cpuinfo looks like the easiest and most generic place.

> and also has to be asked for separately.

yes.

>
> Arguably the microcode version is a natural extension to the existing
> family/model/stepping sequence:
>
> cpu family : 6
> model : 26
> stepping : 5
>
> We'd now see:
>
> cpu family : 6
> model : 26
> stepping : 5
> ucode_version : 17
>
> Where 'stepping' is a hardware revison number and 'ucode_version' is
> a dual software/hw revision number.

Right.

Btw, can we dump the ucode version in hex since ours are much easier to
read that way:

[86483.770976] microcode: CPU0: patch_level=0x010000c4
[86483.826987] microcode: CPU1: patch_level=0x010000c4
[86483.835071] microcode: CPU2: patch_level=0x010000c4
...

I guess for Intel the ucode version format won't matter that much.

> > > > @@ -111,6 +111,8 @@ struct cpuinfo_x86 {
> > > > /* Index into per_cpu list: */
> > > > u16 cpu_index;
> > > > #endif
> > > > + /* CPU update signature */
> > > > + u32 x86_cpu_update;
> > >
> > > This should be cpu_microcode_version instead. We already know its x86 so the
> > > x86_ prefix is superfluous. 'cpu_update' is also rather ambigious and does not
> > > describe much.
> >
> > Or shorter: 'cpu_ucode_version'.
>
> We already know it's a cpu data structure, since it's called 'struct
> cpuinfo_x86' and the local variable is named 'c' which is the typical
> shortcut for that data structure.
>
> so c->ucode_version is the right name here.

even better.

Thanks.

--
Regards/Gruss,
Boris.

Advanced Micro Devices GmbH
Einsteinring 24, 85609 Dornach
General Managers: Alberto Bozzo, Andrew Bowd
Registration: Dornach, Gemeinde Aschheim, Landkreis Muenchen
Registergericht Muenchen, HRB Nr. 43632

\
 
 \ /
  Last update: 2011-05-25 12:53    [W:0.056 / U:0.396 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site