Re: [PATCH 02/14] x86/cpu: Extract cpuid helpers to arch-independent

["Winiarska, Iwona" <iwona.winiarska@intel.com>]

On Wed, 2021-07-14 at 16:58 +0000, Williams, Dan J wrote:
> On Tue, 2021-07-13 at 00:04 +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.
> 
> Just some minor comments below.
> 
> You can go ahead and add:
> 
> Reviewed-by: Dan Williams <dan.j.williams@intel.com>
> 
> > 
> > Signed-off-by: Iwona Winiarska <iwona.winiarska@intel.com>
> > Reviewed-by: Tony Luck <tony.luck@intel.com>
> > ---
> >  MAINTAINERS                      | 2 ++
> >  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                      | 5 +++++
> >  lib/Makefile                     | 2 ++
> >  lib/x86/Makefile                 | 3 +++
> >  {arch/x86/lib => lib/x86}/cpu.c  | 2 +-
> >  12 files changed, 28 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%)
> > 
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index ec5987a00800..6f77aaca2a30 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -20081,6 +20081,8 @@ T:      git
> > git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86/core
> >  F:     Documentation/devicetree/bindings/x86/
> >  F:     Documentation/x86/
> >  F:     arch/x86/
> > +F:     include/linux/x86/
> 
> Doesn't this technically belong in patch1 since that one introduced
> the directory?

In the first patch we are moving arch/x86/include/intel-family.h
content to a new file, which is why I updated MAINTAINERS just for
"INTEL CPU family model numbers".

Here we're moving other content that was maintained under arch/x86
which is why I extended "X86 ARCHITECTURE (32-BIT AND 64-BIT)".

But I agree - "X86 ARCHITECTURE" includes "INTEL CPU family", so I
guess it makes sense to add both in previous patch (otherwise
get_maintainer.pl would produce different output for
include/linux/x86/intel-family.h until this patch is applied).

Thank you
-Iwona

> 
> > +F:     lib/x86/
> >  
> >  X86 ENTRY CODE
> >  M:     Andy Lutomirski <luto@kernel.org>
> > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> > index 49270655e827..750f9b896e4f 100644
> > --- a/arch/x86/Kconfig
> > +++ b/arch/x86/Kconfig
> > @@ -141,6 +141,7 @@ config X86
> >         select GENERIC_IRQ_PROBE
> >         select GENERIC_IRQ_RESERVATION_MODE
> >         select GENERIC_IRQ_SHOW
> > +       select GENERIC_LIB_X86
> >         select GENERIC_PENDING_IRQ              if SMP
> >         select GENERIC_PTDUMP
> >         select GENERIC_SMP_IDLE_THREAD
> > diff --git a/arch/x86/include/asm/cpu.h
> > b/arch/x86/include/asm/cpu.h
> > index 33d41e350c79..2a663a05a795 100644
> > --- a/arch/x86/include/asm/cpu.h
> > +++ b/arch/x86/include/asm/cpu.h
> > @@ -37,9 +37,6 @@ extern int _debug_hotplug_cpu(int cpu, int
> > action);
> >  
> >  int mwait_usable(const struct cpuinfo_x86 *);
> >  
> > -unsigned int x86_family(unsigned int sig);
> > -unsigned int x86_model(unsigned int sig);
> > -unsigned int x86_stepping(unsigned int sig);
> >  #ifdef CONFIG_CPU_SUP_INTEL
> >  extern void __init sld_setup(struct cpuinfo_x86 *c);
> >  extern void switch_to_sld(unsigned long tifn);
> > diff --git a/arch/x86/include/asm/microcode.h
> > b/arch/x86/include/asm/microcode.h
> > index ab45a220fac4..4b0eabf63b98 100644
> > --- a/arch/x86/include/asm/microcode.h
> > +++ b/arch/x86/include/asm/microcode.h
> > @@ -2,9 +2,9 @@
> >  #ifndef _ASM_X86_MICROCODE_H
> >  #define _ASM_X86_MICROCODE_H
> >  
> > -#include <asm/cpu.h>
> >  #include <linux/earlycpio.h>
> >  #include <linux/initrd.h>
> > +#include <linux/x86/cpu.h>
> 
> Has this patch set received a build success notification from the
> kbuild robot? I.e. are you sure that this include was only here for
> the
> 
> unsigned int x86_family(unsigned int sig);
> unsigned int x86_model(unsigned int sig);
> unsigned int x86_stepping(unsigned int sig);
> 
> ...helpers. All the other replacements look trivially verifiable as
> only needing these 3 helpers.
> 
> >  
> >  struct ucode_patch {
> >         struct list_head plist;
> > diff --git a/arch/x86/kvm/cpuid.h b/arch/x86/kvm/cpuid.h
> > index c99edfff7f82..bf070d2a2175 100644
> > --- a/arch/x86/kvm/cpuid.h
> > +++ b/arch/x86/kvm/cpuid.h
> > @@ -4,10 +4,11 @@
> >  
> >  #include "x86.h"
> >  #include "reverse_cpuid.h"
> > -#include <asm/cpu.h>
> >  #include <asm/processor.h>
> >  #include <uapi/asm/kvm_para.h>
> >  
> > +#include <linux/x86/cpu.h>
> > +
> >  extern u32 kvm_cpu_caps[NR_KVM_CPU_CAPS] __read_mostly;
> >  void kvm_set_cpu_caps(void);
> >  
> > diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile
> > index bad4dee4f0e4..fd73c1b72c3e 100644
> > --- a/arch/x86/lib/Makefile
> > +++ b/arch/x86/lib/Makefile
> > @@ -41,7 +41,7 @@ clean-files := inat-tables.c
> >  
> >  obj-$(CONFIG_SMP) += msr-smp.o cache-smp.o
> >  
> > -lib-y := delay.o misc.o cmdline.o cpu.o
> > +lib-y := delay.o misc.o cmdline.o
> >  lib-y += usercopy_$(BITS).o usercopy.o getuser.o putuser.o
> >  lib-y += memcpy_$(BITS).o
> >  lib-$(CONFIG_ARCH_HAS_COPY_MC) += copy_mc.o copy_mc_64.o
> > diff --git a/drivers/edac/mce_amd.c b/drivers/edac/mce_amd.c
> > index 27d56920b469..f545f5fad02c 100644
> > --- a/drivers/edac/mce_amd.c
> > +++ b/drivers/edac/mce_amd.c
> > @@ -1,8 +1,7 @@
> >  // SPDX-License-Identifier: GPL-2.0-only
> >  #include <linux/module.h>
> >  #include <linux/slab.h>
> > -
> > -#include <asm/cpu.h>
> > +#include <linux/x86/cpu.h>
> >  
> >  #include "mce_amd.h"
> >  
> > diff --git a/include/linux/x86/cpu.h b/include/linux/x86/cpu.h
> > new file mode 100644
> > index 000000000000..5f383d47886d
> > --- /dev/null
> > +++ b/include/linux/x86/cpu.h
> > @@ -0,0 +1,9 @@
> > +/* SPDX-License-Identifier: GPL-2.0-only */
> > +#ifndef _LINUX_X86_CPU_H
> > +#define _LINUX_X86_CPU_H
> > +
> > +unsigned int x86_family(unsigned int sig);
> > +unsigned int x86_model(unsigned int sig);
> > +unsigned int x86_stepping(unsigned int sig);
> > +
> > +#endif /* _LINUX_X86_CPU_H */
> > diff --git a/lib/Kconfig b/lib/Kconfig
> > index d241fe476fda..cc28bc1f2d84 100644
> > --- a/lib/Kconfig
> > +++ b/lib/Kconfig
> > @@ -718,3 +718,8 @@ config PLDMFW
> >  
> >  config ASN1_ENCODER
> >         tristate
> > +
> > +config GENERIC_LIB_X86
> > +       bool
> > +       depends on X86
> > +       default n
> 
> No need for a "default n" line. Omitting a default is the same as
> "default n".
>