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

Iwona Winiarska
2021-07-12T22:07:49Z

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>
---
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/
+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>

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
diff --git a/lib/Makefile b/lib/Makefile
index 5efd1b435a37..befbd9413432 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -360,3 +360,5 @@ obj-$(CONFIG_CMDLINE_KUNIT_TEST) += cmdline_kunit.o
obj-$(CONFIG_SLUB_KUNIT_TEST) += slub_kunit.o

obj-$(CONFIG_GENERIC_LIB_DEVMEM_IS_ALLOWED) += devmem_is_allowed.o
+
+obj-$(CONFIG_GENERIC_LIB_X86) += x86/
diff --git a/lib/x86/Makefile b/lib/x86/Makefile
new file mode 100644
index 000000000000..342024c272fc
--- /dev/null
+++ b/lib/x86/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+obj-y := cpu.o
diff --git a/arch/x86/lib/cpu.c b/lib/x86/cpu.c
similarity index 95%
rename from arch/x86/lib/cpu.c
rename to lib/x86/cpu.c
index 7ad68917a51e..17af59a2fddf 100644
--- a/arch/x86/lib/cpu.c
+++ b/lib/x86/cpu.c
@@ -1,7 +1,7 @@
// SPDX-License-Identifier: GPL-2.0-only
#include <linux/types.h>
#include <linux/export.h>
-#include <asm/cpu.h>
+#include <linux/x86/cpu.h>

unsigned int x86_family(unsigned int sig)
{
--
2.31.1