From mboxrd@z Thu Jan  1 00:00:00 1970
From: Winiarska, Iwona <iwona.winiarska@intel.com>
Date: Mon, 11 Oct 2021 19:32:38 +0000
Subject: [PATCH v2 02/15] x86/cpu: Extract cpuid helpers to
 arch-independent
In-Reply-To: <YVtRJiYD9EqGh7TM@zn.tnic>
References: <20210803113134.2262882-1-iwona.winiarska@intel.com>
 <20210803113134.2262882-3-iwona.winiarska@intel.com>
 <YVtRJiYD9EqGh7TM@zn.tnic>
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On Mon, 2021-10-04 at 21:08 +0200, Borislav Petkov wrote:
> On Tue, Aug 03, 2021 at 01:31:21PM +0200, Iwona Winiarska wrote:
> > Baseboard management controllers (BMC) often run Linux but are usually
> > implemented with non-X86 processors. They can use PECI to access package
> > config space (PCS) registers on the host CPU and since some information,
> > e.g. figuring out the core count, can be obtained using different
> > registers on different CPU generations, they need to decode the family
> > and model.
> > 
> > The format of Package Identifier PCS register that describes CPUID
> > information has the same layout as CPUID_1.EAX, so let's allow to reuse
> > cpuid helpers by making it available for other architectures as well.
> > 
> > Signed-off-by: Iwona Winiarska <iwona.winiarska@intel.com>
> > Reviewed-by: Tony Luck <tony.luck@intel.com>
> > Reviewed-by: Dan Williams <dan.j.williams@intel.com>
> > ---
> > ?MAINTAINERS????????????????????? | 1 +
> > ?arch/x86/Kconfig???????????????? | 1 +
> > ?arch/x86/include/asm/cpu.h?????? | 3 ---
> > ?arch/x86/include/asm/microcode.h | 2 +-
> > ?arch/x86/kvm/cpuid.h???????????? | 3 ++-
> > ?arch/x86/lib/Makefile??????????? | 2 +-
> > ?drivers/edac/mce_amd.c?????????? | 3 +--
> > ?include/linux/x86/cpu.h????????? | 9 +++++++++
> > ?lib/Kconfig????????????????????? | 4 ++++
> > ?lib/Makefile???????????????????? | 2 ++
> > ?lib/x86/Makefile???????????????? | 3 +++
> > ?{arch/x86/lib => lib/x86}/cpu.c? | 2 +-
> > ?12 files changed, 26 insertions(+), 9 deletions(-)
> > ?create mode 100644 include/linux/x86/cpu.h
> > ?create mode 100644 lib/x86/Makefile
> > ?rename {arch/x86/lib => lib/x86}/cpu.c (95%)
> 
> AFAICT, all that churn is done for x86_family() and x86_model() which
> are used *exactly* *once* and which are almost trivial anyway.

Correct.

> What's wrong with simply computing the family and model "by hand", so to
> speak, in peci_device_info_init() and do away with that diffstat
> 
> ?12 files changed, 26 insertions(+), 9 deletions(-)
> 
> ?

Nothing wrong - just a trade-off between churn and keeping things tidy and not
duplicated, similar to patch 1.
And just like in patch 1, if you have a strong opinion against it - we can
duplicate. 

Thanks
-Iwona