Re: [RFC PATCH 1/3] x86/cpu: Unify CPU family, model, stepping calculation

From: Borislav Petkov
Date: Wed Nov 18 2015 - 13:50:34 EST


On Wed, Nov 18, 2015 at 12:35:24PM +0100, Paolo Bonzini wrote:
> Yes, exactly. I'm suggesting that the same applies to x86_vendor(). I
> also prefer x86_cpuid_* to x86_*_cpuid because, once you add two
> functions in the same family it's nice that they share a prefix.

Ok, makes sense:

---
commit 804437270083a1aabf87f65f65b32e2ae23121b6
Author: Borislav Petkov <bp@xxxxxxx>
Date: Sat Nov 14 10:54:22 2015 +0100

x86/cpu: Unify CPU family, model, stepping calculation

Add generic functions which calc family, model and stepping from the
CPUID_1.EAX leaf and stick them into the library we have.

Rename those which do call CPUID with the prefix "x86_cpuid" as
suggested by Paolo Bonzini.

No functionality change.

Signed-off-by: Borislav Petkov <bp@xxxxxxx>

diff --git a/arch/x86/include/asm/cpu.h b/arch/x86/include/asm/cpu.h
index bf2caa1dedc5..678637ad7476 100644
--- a/arch/x86/include/asm/cpu.h
+++ b/arch/x86/include/asm/cpu.h
@@ -36,4 +36,7 @@ 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);
#endif /* _ASM_X86_CPU_H */
diff --git a/arch/x86/include/asm/microcode.h b/arch/x86/include/asm/microcode.h
index 34e62b1dcfce..1e1b07a5a738 100644
--- a/arch/x86/include/asm/microcode.h
+++ b/arch/x86/include/asm/microcode.h
@@ -1,6 +1,7 @@
#ifndef _ASM_X86_MICROCODE_H
#define _ASM_X86_MICROCODE_H

+#include <asm/cpu.h>
#include <linux/earlycpio.h>

#define native_rdmsr(msr, val1, val2) \
@@ -95,14 +96,14 @@ static inline void __exit exit_amd_microcode(void) {}

/*
* In early loading microcode phase on BSP, boot_cpu_data is not set up yet.
- * x86_vendor() gets vendor id for BSP.
+ * x86_cpuid_vendor() gets vendor id for BSP.
*
* In 32 bit AP case, accessing boot_cpu_data needs linear address. To simplify
- * coding, we still use x86_vendor() to get vendor id for AP.
+ * coding, we still use x86_cpuid_vendor() to get vendor id for AP.
*
- * x86_vendor() gets vendor information directly from CPUID.
+ * x86_cpuid_vendor() gets vendor information directly from CPUID.
*/
-static inline int x86_vendor(void)
+static inline int x86_cpuid_vendor(void)
{
u32 eax = 0x00000000;
u32 ebx, ecx = 0, edx;
@@ -118,40 +119,14 @@ static inline int x86_vendor(void)
return X86_VENDOR_UNKNOWN;
}

-static inline unsigned int __x86_family(unsigned int sig)
-{
- unsigned int x86;
-
- x86 = (sig >> 8) & 0xf;
-
- if (x86 == 0xf)
- x86 += (sig >> 20) & 0xff;
-
- return x86;
-}
-
-static inline unsigned int x86_family(void)
+static inline unsigned int x86_cpuid_family(void)
{
u32 eax = 0x00000001;
u32 ebx, ecx = 0, edx;

native_cpuid(&eax, &ebx, &ecx, &edx);

- return __x86_family(eax);
-}
-
-static inline unsigned int x86_model(unsigned int sig)
-{
- unsigned int x86, model;
-
- x86 = __x86_family(sig);
-
- model = (sig >> 4) & 0xf;
-
- if (x86 == 0x6 || x86 == 0xf)
- model += ((sig >> 16) & 0xf) << 4;
-
- return model;
+ return x86_family(eax);
}

#ifdef CONFIG_MICROCODE
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 4ddd780aeac9..c311b51efe15 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -582,14 +582,9 @@ void cpu_detect(struct cpuinfo_x86 *c)
u32 junk, tfms, cap0, misc;

cpuid(0x00000001, &tfms, &misc, &junk, &cap0);
- c->x86 = (tfms >> 8) & 0xf;
- c->x86_model = (tfms >> 4) & 0xf;
- c->x86_mask = tfms & 0xf;
-
- if (c->x86 == 0xf)
- c->x86 += (tfms >> 20) & 0xff;
- if (c->x86 >= 0x6)
- c->x86_model += ((tfms >> 16) & 0xf) << 4;
+ c->x86 = x86_family(tfms);
+ c->x86_model = x86_model(tfms);
+ c->x86_mask = x86_stepping(tfms);

if (cap0 & (1<<19)) {
c->x86_clflush_size = ((misc >> 8) & 0xff) * 8;
diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c
index 7fc27f1cca58..3aaffb601c91 100644
--- a/arch/x86/kernel/cpu/microcode/core.c
+++ b/arch/x86/kernel/cpu/microcode/core.c
@@ -129,8 +129,8 @@ void __init load_ucode_bsp(void)
if (!have_cpuid_p())
return;

- vendor = x86_vendor();
- family = x86_family();
+ vendor = x86_cpuid_vendor();
+ family = x86_cpuid_family();

switch (vendor) {
case X86_VENDOR_INTEL:
@@ -165,8 +165,8 @@ void load_ucode_ap(void)
if (!have_cpuid_p())
return;

- vendor = x86_vendor();
- family = x86_family();
+ vendor = x86_cpuid_vendor();
+ family = x86_cpuid_family();

switch (vendor) {
case X86_VENDOR_INTEL:
@@ -206,8 +206,8 @@ void reload_early_microcode(void)
{
int vendor, family;

- vendor = x86_vendor();
- family = x86_family();
+ vendor = x86_cpuid_vendor();
+ family = x86_cpuid_family();

switch (vendor) {
case X86_VENDOR_INTEL:
diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c
index ce47402eb2f9..ee81c544ee0d 100644
--- a/arch/x86/kernel/cpu/microcode/intel.c
+++ b/arch/x86/kernel/cpu/microcode/intel.c
@@ -145,10 +145,10 @@ matching_model_microcode(struct microcode_header_intel *mc_header,
int ext_sigcount, i;
struct extended_signature *ext_sig;

- fam = __x86_family(sig);
+ fam = x86_family(sig);
model = x86_model(sig);

- fam_ucode = __x86_family(mc_header->sig);
+ fam_ucode = x86_family(mc_header->sig);
model_ucode = x86_model(mc_header->sig);

if (fam == fam_ucode && model == model_ucode)
@@ -163,7 +163,7 @@ matching_model_microcode(struct microcode_header_intel *mc_header,
ext_sigcount = ext_header->count;

for (i = 0; i < ext_sigcount; i++) {
- fam_ucode = __x86_family(ext_sig->sig);
+ fam_ucode = x86_family(ext_sig->sig);
model_ucode = x86_model(ext_sig->sig);

if (fam == fam_ucode && model == model_ucode)
@@ -365,7 +365,7 @@ static int collect_cpu_info_early(struct ucode_cpu_info *uci)
native_cpuid(&eax, &ebx, &ecx, &edx);
csig.sig = eax;

- family = __x86_family(csig.sig);
+ family = x86_family(csig.sig);
model = x86_model(csig.sig);

if ((model >= 5) || (family > 6)) {
@@ -521,16 +521,12 @@ static bool __init load_builtin_intel_microcode(struct cpio_data *cp)
{
#ifdef CONFIG_X86_64
unsigned int eax = 0x00000001, ebx, ecx = 0, edx;
- unsigned int family, model, stepping;
char name[30];

native_cpuid(&eax, &ebx, &ecx, &edx);

- family = __x86_family(eax);
- model = x86_model(eax);
- stepping = eax & 0xf;
-
- sprintf(name, "intel-ucode/%02x-%02x-%02x", family, model, stepping);
+ sprintf(name, "intel-ucode/%02x-%02x-%02x",
+ x86_family(eax), x86_model(eax), x86_stepping(eax));

return get_builtin_firmware(cp, name);
#else
diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile
index f2587888d987..a501fa25da41 100644
--- a/arch/x86/lib/Makefile
+++ b/arch/x86/lib/Makefile
@@ -16,7 +16,7 @@ clean-files := inat-tables.c

obj-$(CONFIG_SMP) += msr-smp.o cache-smp.o

-lib-y := delay.o misc.o cmdline.o
+lib-y := delay.o misc.o cmdline.o cpu.o
lib-y += usercopy_$(BITS).o usercopy.o getuser.o putuser.o
lib-y += memcpy_$(BITS).o
lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem.o
diff --git a/arch/x86/lib/cpu.c b/arch/x86/lib/cpu.c
new file mode 100644
index 000000000000..aa417a97511c
--- /dev/null
+++ b/arch/x86/lib/cpu.c
@@ -0,0 +1,35 @@
+#include <linux/module.h>
+
+unsigned int x86_family(unsigned int sig)
+{
+ unsigned int x86;
+
+ x86 = (sig >> 8) & 0xf;
+
+ if (x86 == 0xf)
+ x86 += (sig >> 20) & 0xff;
+
+ return x86;
+}
+EXPORT_SYMBOL_GPL(x86_family);
+
+unsigned int x86_model(unsigned int sig)
+{
+ unsigned int fam, model;
+
+ fam = x86_family(sig);
+
+ model = (sig >> 4) & 0xf;
+
+ if (fam >= 0x6)
+ model += ((sig >> 16) & 0xf) << 4;
+
+ return model;
+}
+EXPORT_SYMBOL_GPL(x86_model);
+
+unsigned int x86_stepping(unsigned int sig)
+{
+ return sig & 0xf;
+}
+EXPORT_SYMBOL_GPL(x86_stepping);

--
Regards/Gruss,
Boris.

ECO tip #101: Trim your mails when you reply.
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