[PATCH v2 0/2] generic CPU feature based udev module autoprobing

[PATCH v2 0/2] generic CPU feature based udev module autoprobing

[Ard Biesheuvel]

This series implements a generic way to wire up udev module autoprobing to
optional CPU features.

Patch #1 implements the actual generic part. It relies on the include file
<asm/cpufeature.h> to be supplied by the architecture to map CPU features to
the number based scheme used by modalias.

Patch #2 aligns x86 with the generic code. As x86 allows matching on CPU vendor,
family and model IDs, it still retains much of the original code for creating
the module metadata.

Changes since v1:
- squashed into 2 patches, all the generic bits are now added in patch #1 and
  all alignment of the x86 code with the newly introduced generic code is done
  in patch #2
- add more elaborate commit message for patch #1
- added hpa's ack on patch #2

Ard Biesheuvel (2):
  cpu: add generic support for CPU feature based module autoloading
  x86: align x86 arch with generic CPU modalias handling

 arch/x86/Kconfig                  |  4 +--
 arch/x86/include/asm/cpufeature.h |  7 +++++
 arch/x86/kernel/cpu/match.c       | 42 ---------------------------
 drivers/base/Kconfig              |  3 ++
 drivers/base/cpu.c                | 46 ++++++++++++++++++++++++++----
 include/linux/cpu.h               |  7 -----
 include/linux/cpufeature.h        | 60 +++++++++++++++++++++++++++++++++++++++
 include/linux/mod_devicetable.h   |  9 ++++++
 scripts/mod/devicetable-offsets.c |  3 ++
 scripts/mod/file2alias.c          | 20 +++++++++----
 10 files changed, 139 insertions(+), 62 deletions(-)
 create mode 100644 include/linux/cpufeature.h

-- 
1.8.3.2

[PATCH v2 1/2] cpu: add generic support for CPU feature based module autoloading

[Ard Biesheuvel]

This patch adds support for advertising optional CPU features over udev
using the modalias, and for declaring compatibility with/dependency upon
such a feature in a module.

The mapping between feature numbers and actual features should be provided
by the architecture in a file called <asm/cpufeature.h> which exports the
following functions/macros:
- cpu_feature(FEAT), a preprocessor macro that maps token FEAT to a
  numeric index;
- bool cpu_have_feature(n), returning whether this CPU has support for
  feature #n;
- MAX_CPU_FEATURES, an upper bound for 'n' in the previous function.

The feature can then be enabled by setting CONFIG_GENERIC_CPU_AUTOPROBE
for the architecture.

For instance, a module that registers its module init function using

  module_cpu_feature_match(FEAT_X, module_init_function)

will be probed automatically when the CPU's support for the 'FEAT_X'
feature is advertised over udev, and will only allow the module to be
loaded by hand if the 'FEAT_X' feature is supported.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 drivers/base/Kconfig              |  8 ++++++
 drivers/base/cpu.c                | 50 ++++++++++++++++++++++++++++----
 include/linux/cpufeature.h        | 60 +++++++++++++++++++++++++++++++++++++++
 include/linux/mod_devicetable.h   |  9 ++++++
 scripts/mod/devicetable-offsets.c |  3 ++
 scripts/mod/file2alias.c          | 10 +++++++
 6 files changed, 135 insertions(+), 5 deletions(-)
 create mode 100644 include/linux/cpufeature.h

diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
index ec36e77..3f0d373 100644
--- a/drivers/base/Kconfig
+++ b/drivers/base/Kconfig
@@ -185,6 +185,14 @@ config GENERIC_CPU_DEVICES
 	bool
 	default n
 
+config HAVE_CPU_AUTOPROBE
+	def_bool ARCH_HAS_CPU_AUTOPROBE
+
+config GENERIC_CPU_AUTOPROBE
+	bool
+	depends on !ARCH_HAS_CPU_AUTOPROBE
+	select HAVE_CPU_AUTOPROBE
+
 config SOC_BUS
 	bool
 
diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
index f48370d..8a38bf8 100644
--- a/drivers/base/cpu.c
+++ b/drivers/base/cpu.c
@@ -15,6 +15,7 @@
 #include <linux/percpu.h>
 #include <linux/acpi.h>
 #include <linux/of.h>
+#include <linux/cpufeature.h>
 
 #include "base.h"
 
@@ -286,6 +287,45 @@ static void cpu_device_release(struct device *dev)
 	 */
 }
 
+#ifdef CONFIG_HAVE_CPU_AUTOPROBE
+#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
+static ssize_t print_cpu_modalias(struct device *dev,
+				  struct device_attribute *attr,
+				  char *buf)
+{
+	ssize_t n;
+	u32 i;
+
+	n = sprintf(buf, "cpu:type:" CPU_FEATURE_TYPEFMT ":feature:",
+		    CPU_FEATURE_TYPEVAL);
+
+	for (i = 0; i < MAX_CPU_FEATURES; i++)
+		if (cpu_have_feature(i)) {
+			if (PAGE_SIZE < n + sizeof(",XXXX\n")) {
+				WARN(1, "CPU features overflow page\n");
+				break;
+			}
+			n += sprintf(&buf[n], ",%04X", i);
+		}
+	buf[n++] = '\n';
+	return n;
+}
+#else
+#define print_cpu_modalias	arch_print_cpu_modalias
+#endif
+
+static int cpu_uevent(struct device *dev, struct kobj_uevent_env *env)
+{
+	char *buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
+	if (buf) {
+		print_cpu_modalias(NULL, NULL, buf);
+		add_uevent_var(env, "MODALIAS=%s", buf);
+		kfree(buf);
+	}
+	return 0;
+}
+#endif
+
 /*
  * register_cpu - Setup a sysfs device for a CPU.
  * @cpu - cpu->hotpluggable field set to 1 will generate a control file in
@@ -306,8 +346,8 @@ int register_cpu(struct cpu *cpu, int num)
 	cpu->dev.offline_disabled = !cpu->hotpluggable;
 	cpu->dev.offline = !cpu_online(num);
 	cpu->dev.of_node = of_get_cpu_node(num, NULL);
-#ifdef CONFIG_ARCH_HAS_CPU_AUTOPROBE
-	cpu->dev.bus->uevent = arch_cpu_uevent;
+#ifdef CONFIG_HAVE_CPU_AUTOPROBE
+	cpu->dev.bus->uevent = cpu_uevent;
 #endif
 	cpu->dev.groups = common_cpu_attr_groups;
 	if (cpu->hotpluggable)
@@ -330,8 +370,8 @@ struct device *get_cpu_device(unsigned cpu)
 }
 EXPORT_SYMBOL_GPL(get_cpu_device);
 
-#ifdef CONFIG_ARCH_HAS_CPU_AUTOPROBE
-static DEVICE_ATTR(modalias, 0444, arch_print_cpu_modalias, NULL);
+#ifdef CONFIG_HAVE_CPU_AUTOPROBE
+static DEVICE_ATTR(modalias, 0444, print_cpu_modalias, NULL);
 #endif
 
 static struct attribute *cpu_root_attrs[] = {
@@ -344,7 +384,7 @@ static struct attribute *cpu_root_attrs[] = {
 	&cpu_attrs[2].attr.attr,
 	&dev_attr_kernel_max.attr,
 	&dev_attr_offline.attr,
-#ifdef CONFIG_ARCH_HAS_CPU_AUTOPROBE
+#ifdef CONFIG_HAVE_CPU_AUTOPROBE
 	&dev_attr_modalias.attr,
 #endif
 	NULL
diff --git a/include/linux/cpufeature.h b/include/linux/cpufeature.h
new file mode 100644
index 0000000..c4d4eb8
--- /dev/null
+++ b/include/linux/cpufeature.h
@@ -0,0 +1,60 @@
+/*
+ * Copyright (C) 2014 Linaro Ltd. <ard.biesheuvel@linaro.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef __LINUX_CPUFEATURE_H
+#define __LINUX_CPUFEATURE_H
+
+#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
+
+#include <linux/mod_devicetable.h>
+#include <asm/cpufeature.h>
+
+/*
+ * Macros imported from <asm/cpufeature.h>:
+ * - cpu_feature(x)		ordinal value of feature called 'x'
+ * - cpu_have_feature(u32 n)	whether feature #n is available
+ * - MAX_CPU_FEATURES		upper bound for feature ordinal values
+ * Optional:
+ * - CPU_FEATURE_TYPEFMT	format string fragment for printing the cpu type
+ * - CPU_FEATURE_TYPEVAL	set of values matching the format string above
+ */
+
+#ifndef CPU_FEATURE_TYPEFMT
+#define CPU_FEATURE_TYPEFMT	"%s"
+#endif
+
+#ifndef CPU_FEATURE_TYPEVAL
+#define CPU_FEATURE_TYPEVAL	ELF_PLATFORM
+#endif
+
+/*
+ * Use module_cpu_feature_match(feature, module_init_function) to
+ * declare that
+ * a) the module shall be probed upon discovery of CPU feature 'feature'
+ *    (typically at boot time using udev)
+ * b) the module must not be loaded if CPU feature 'feature' is not present
+ *    (not even by manual insmod).
+ *
+ * For a list of legal values for 'feature', please consult the file
+ * 'asm/cpufeature.h' of your favorite architecture.
+ */
+#define module_cpu_feature_match(x, __init)			\
+static struct cpu_feature const cpu_feature_match_ ## x[] =	\
+	{ { .feature = cpu_feature(x) }, { } };			\
+MODULE_DEVICE_TABLE(cpu, cpu_feature_match_ ## x);		\
+								\
+static int cpu_feature_match_ ## x ## _init(void)		\
+{								\
+	if (!cpu_have_feature(cpu_feature(x)))			\
+		return -ENODEV;					\
+	return __init();					\
+}								\
+module_init(cpu_feature_match_ ## x ## _init)
+
+#endif
+#endif
diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
index 45e9214..f2ac87c 100644
--- a/include/linux/mod_devicetable.h
+++ b/include/linux/mod_devicetable.h
@@ -564,6 +564,15 @@ struct x86_cpu_id {
 #define X86_MODEL_ANY  0
 #define X86_FEATURE_ANY 0	/* Same as FPU, you can't test for that */
 
+/*
+ * Generic table type for matching CPU features.
+ * @feature:	the bit number of the feature (0 - 65535)
+ */
+
+struct cpu_feature {
+	__u16	feature;
+};
+
 #define IPACK_ANY_FORMAT 0xff
 #define IPACK_ANY_ID (~0)
 struct ipack_device_id {
diff --git a/scripts/mod/devicetable-offsets.c b/scripts/mod/devicetable-offsets.c
index bb5d115..f282516 100644
--- a/scripts/mod/devicetable-offsets.c
+++ b/scripts/mod/devicetable-offsets.c
@@ -174,6 +174,9 @@ int main(void)
 	DEVID_FIELD(x86_cpu_id, model);
 	DEVID_FIELD(x86_cpu_id, vendor);
 
+	DEVID(cpu_feature);
+	DEVID_FIELD(cpu_feature, feature);
+
 	DEVID(mei_cl_device_id);
 	DEVID_FIELD(mei_cl_device_id, name);
 
diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c
index 2370863..8a69005 100644
--- a/scripts/mod/file2alias.c
+++ b/scripts/mod/file2alias.c
@@ -1135,6 +1135,16 @@ static int do_x86cpu_entry(const char *filename, void *symval,
 }
 ADD_TO_DEVTABLE("x86cpu", x86_cpu_id, do_x86cpu_entry);
 
+/* LOOKS like cpu:type:*:feature:*FEAT* */
+static int do_cpu_entry(const char *filename, void *symval, char *alias)
+{
+	DEF_FIELD(symval, cpu_feature, feature);
+
+	sprintf(alias, "cpu:type:*:feature:*%04X*", feature);
+	return 1;
+}
+ADD_TO_DEVTABLE("cpu", cpu_feature, do_cpu_entry);
+
 /* Looks like: mei:S */
 static int do_mei_entry(const char *filename, void *symval,
 			char *alias)
-- 
1.8.3.2

[PATCH v2 1/2] cpu: add generic support for CPU feature based module autoloading

[Ard Biesheuvel]

This patch adds support for advertising optional CPU features over udev
using the modalias, and for declaring compatibility with/dependency upon
such a feature in a module.

The mapping between feature numbers and actual features should be provided
by the architecture in a file called <asm/cpufeature.h> which exports the
following functions/macros:
- cpu_feature(FEAT), a preprocessor macro that maps token FEAT to a
  numeric index;
- bool cpu_have_feature(n), returning whether this CPU has support for
  feature #n;
- MAX_CPU_FEATURES, an upper bound for 'n' in the previous function.

The feature can then be enabled by setting CONFIG_GENERIC_CPU_AUTOPROBE
for the architecture.

For instance, a module that registers its module init function using

  module_cpu_feature_match(FEAT_X, module_init_function)

will be probed automatically when the CPU's support for the 'FEAT_X'
feature is advertised over udev, and will only allow the module to be
loaded by hand if the 'FEAT_X' feature is supported.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 drivers/base/Kconfig              |  8 ++++++
 drivers/base/cpu.c                | 50 ++++++++++++++++++++++++++++----
 include/linux/cpufeature.h        | 60 +++++++++++++++++++++++++++++++++++++++
 include/linux/mod_devicetable.h   |  9 ++++++
 scripts/mod/devicetable-offsets.c |  3 ++
 scripts/mod/file2alias.c          | 10 +++++++
 6 files changed, 135 insertions(+), 5 deletions(-)
 create mode 100644 include/linux/cpufeature.h

diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
index ec36e77..3f0d373 100644
--- a/drivers/base/Kconfig
+++ b/drivers/base/Kconfig
@@ -185,6 +185,14 @@ config GENERIC_CPU_DEVICES
 	bool
 	default n
 
+config HAVE_CPU_AUTOPROBE
+	def_bool ARCH_HAS_CPU_AUTOPROBE
+
+config GENERIC_CPU_AUTOPROBE
+	bool
+	depends on !ARCH_HAS_CPU_AUTOPROBE
+	select HAVE_CPU_AUTOPROBE
+
 config SOC_BUS
 	bool
 
diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
index f48370d..8a38bf8 100644
--- a/drivers/base/cpu.c
+++ b/drivers/base/cpu.c
@@ -15,6 +15,7 @@
 #include <linux/percpu.h>
 #include <linux/acpi.h>
 #include <linux/of.h>
+#include <linux/cpufeature.h>
 
 #include "base.h"
 
@@ -286,6 +287,45 @@ static void cpu_device_release(struct device *dev)
 	 */
 }
 
+#ifdef CONFIG_HAVE_CPU_AUTOPROBE
+#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
+static ssize_t print_cpu_modalias(struct device *dev,
+				  struct device_attribute *attr,
+				  char *buf)
+{
+	ssize_t n;
+	u32 i;
+
+	n = sprintf(buf, "cpu:type:" CPU_FEATURE_TYPEFMT ":feature:",
+		    CPU_FEATURE_TYPEVAL);
+
+	for (i = 0; i < MAX_CPU_FEATURES; i++)
+		if (cpu_have_feature(i)) {
+			if (PAGE_SIZE < n + sizeof(",XXXX\n")) {
+				WARN(1, "CPU features overflow page\n");
+				break;
+			}
+			n += sprintf(&buf[n], ",%04X", i);
+		}
+	buf[n++] = '\n';
+	return n;
+}
+#else
+#define print_cpu_modalias	arch_print_cpu_modalias
+#endif
+
+static int cpu_uevent(struct device *dev, struct kobj_uevent_env *env)
+{
+	char *buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
+	if (buf) {
+		print_cpu_modalias(NULL, NULL, buf);
+		add_uevent_var(env, "MODALIAS=%s", buf);
+		kfree(buf);
+	}
+	return 0;
+}
+#endif
+
 /*
  * register_cpu - Setup a sysfs device for a CPU.
  * @cpu - cpu->hotpluggable field set to 1 will generate a control file in
@@ -306,8 +346,8 @@ int register_cpu(struct cpu *cpu, int num)
 	cpu->dev.offline_disabled = !cpu->hotpluggable;
 	cpu->dev.offline = !cpu_online(num);
 	cpu->dev.of_node = of_get_cpu_node(num, NULL);
-#ifdef CONFIG_ARCH_HAS_CPU_AUTOPROBE
-	cpu->dev.bus->uevent = arch_cpu_uevent;
+#ifdef CONFIG_HAVE_CPU_AUTOPROBE
+	cpu->dev.bus->uevent = cpu_uevent;
 #endif
 	cpu->dev.groups = common_cpu_attr_groups;
 	if (cpu->hotpluggable)
@@ -330,8 +370,8 @@ struct device *get_cpu_device(unsigned cpu)
 }
 EXPORT_SYMBOL_GPL(get_cpu_device);
 
-#ifdef CONFIG_ARCH_HAS_CPU_AUTOPROBE
-static DEVICE_ATTR(modalias, 0444, arch_print_cpu_modalias, NULL);
+#ifdef CONFIG_HAVE_CPU_AUTOPROBE
+static DEVICE_ATTR(modalias, 0444, print_cpu_modalias, NULL);
 #endif
 
 static struct attribute *cpu_root_attrs[] = {
@@ -344,7 +384,7 @@ static struct attribute *cpu_root_attrs[] = {
 	&cpu_attrs[2].attr.attr,
 	&dev_attr_kernel_max.attr,
 	&dev_attr_offline.attr,
-#ifdef CONFIG_ARCH_HAS_CPU_AUTOPROBE
+#ifdef CONFIG_HAVE_CPU_AUTOPROBE
 	&dev_attr_modalias.attr,
 #endif
 	NULL
diff --git a/include/linux/cpufeature.h b/include/linux/cpufeature.h
new file mode 100644
index 0000000..c4d4eb8
--- /dev/null
+++ b/include/linux/cpufeature.h
@@ -0,0 +1,60 @@
+/*
+ * Copyright (C) 2014 Linaro Ltd. <ard.biesheuvel@linaro.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef __LINUX_CPUFEATURE_H
+#define __LINUX_CPUFEATURE_H
+
+#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
+
+#include <linux/mod_devicetable.h>
+#include <asm/cpufeature.h>
+
+/*
+ * Macros imported from <asm/cpufeature.h>:
+ * - cpu_feature(x)		ordinal value of feature called 'x'
+ * - cpu_have_feature(u32 n)	whether feature #n is available
+ * - MAX_CPU_FEATURES		upper bound for feature ordinal values
+ * Optional:
+ * - CPU_FEATURE_TYPEFMT	format string fragment for printing the cpu type
+ * - CPU_FEATURE_TYPEVAL	set of values matching the format string above
+ */
+
+#ifndef CPU_FEATURE_TYPEFMT
+#define CPU_FEATURE_TYPEFMT	"%s"
+#endif
+
+#ifndef CPU_FEATURE_TYPEVAL
+#define CPU_FEATURE_TYPEVAL	ELF_PLATFORM
+#endif
+
+/*
+ * Use module_cpu_feature_match(feature, module_init_function) to
+ * declare that
+ * a) the module shall be probed upon discovery of CPU feature 'feature'
+ *    (typically at boot time using udev)
+ * b) the module must not be loaded if CPU feature 'feature' is not present
+ *    (not even by manual insmod).
+ *
+ * For a list of legal values for 'feature', please consult the file
+ * 'asm/cpufeature.h' of your favorite architecture.
+ */
+#define module_cpu_feature_match(x, __init)			\
+static struct cpu_feature const cpu_feature_match_ ## x[] =	\
+	{ { .feature = cpu_feature(x) }, { } };			\
+MODULE_DEVICE_TABLE(cpu, cpu_feature_match_ ## x);		\
+								\
+static int cpu_feature_match_ ## x ## _init(void)		\
+{								\
+	if (!cpu_have_feature(cpu_feature(x)))			\
+		return -ENODEV;					\
+	return __init();					\
+}								\
+module_init(cpu_feature_match_ ## x ## _init)
+
+#endif
+#endif
diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
index 45e9214..f2ac87c 100644
--- a/include/linux/mod_devicetable.h
+++ b/include/linux/mod_devicetable.h
@@ -564,6 +564,15 @@ struct x86_cpu_id {
 #define X86_MODEL_ANY  0
 #define X86_FEATURE_ANY 0	/* Same as FPU, you can't test for that */
 
+/*
+ * Generic table type for matching CPU features.
+ * @feature:	the bit number of the feature (0 - 65535)
+ */
+
+struct cpu_feature {
+	__u16	feature;
+};
+
 #define IPACK_ANY_FORMAT 0xff
 #define IPACK_ANY_ID (~0)
 struct ipack_device_id {
diff --git a/scripts/mod/devicetable-offsets.c b/scripts/mod/devicetable-offsets.c
index bb5d115..f282516 100644
--- a/scripts/mod/devicetable-offsets.c
+++ b/scripts/mod/devicetable-offsets.c
@@ -174,6 +174,9 @@ int main(void)
 	DEVID_FIELD(x86_cpu_id, model);
 	DEVID_FIELD(x86_cpu_id, vendor);
 
+	DEVID(cpu_feature);
+	DEVID_FIELD(cpu_feature, feature);
+
 	DEVID(mei_cl_device_id);
 	DEVID_FIELD(mei_cl_device_id, name);
 
diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c
index 2370863..8a69005 100644
--- a/scripts/mod/file2alias.c
+++ b/scripts/mod/file2alias.c
@@ -1135,6 +1135,16 @@ static int do_x86cpu_entry(const char *filename, void *symval,
 }
 ADD_TO_DEVTABLE("x86cpu", x86_cpu_id, do_x86cpu_entry);
 
+/* LOOKS like cpu:type:*:feature:*FEAT* */
+static int do_cpu_entry(const char *filename, void *symval, char *alias)
+{
+	DEF_FIELD(symval, cpu_feature, feature);
+
+	sprintf(alias, "cpu:type:*:feature:*%04X*", feature);
+	return 1;
+}
+ADD_TO_DEVTABLE("cpu", cpu_feature, do_cpu_entry);
+
 /* Looks like: mei:S */
 static int do_mei_entry(const char *filename, void *symval,
 			char *alias)
-- 
1.8.3.2

[PATCH v2 2/2] x86: align x86 arch with generic CPU modalias handling

[Ard Biesheuvel]

The x86 CPU feature modalias handling existed before it was reimplemented
generically. This patch aligns the x86 handling so that it
(a) reuses some more code that is now generic;
(b) uses the generic format for the modalias module metadata entry, i.e., it
    now uses 'cpu:type:x86,venVVVVfamFFFFmodMMMM:feature:,XXXX,YYYY' instead of
    the 'x86cpu:vendor:VVVV:family:FFFF:model:MMMM:feature:,XXXX,YYYY' that was
    used before.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: H. Peter Anvin <hpa@linux.intel.com>
---
 arch/x86/Kconfig                  |  4 +---
 arch/x86/include/asm/cpufeature.h |  7 +++++++
 arch/x86/kernel/cpu/match.c       | 42 ---------------------------------------
 drivers/base/Kconfig              |  5 -----
 drivers/base/cpu.c                | 10 +++-------
 include/linux/cpu.h               |  7 -------
 scripts/mod/file2alias.c          | 10 +++++-----
 7 files changed, 16 insertions(+), 69 deletions(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 940e50e..7d3b790 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -127,6 +127,7 @@ config X86
 	select HAVE_DEBUG_STACKOVERFLOW
 	select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
 	select HAVE_CC_STACKPROTECTOR
+	select GENERIC_CPU_AUTOPROBE
 
 config INSTRUCTION_DECODER
 	def_bool y
@@ -195,9 +196,6 @@ config ARCH_HAS_CPU_RELAX
 config ARCH_HAS_CACHE_LINE_SIZE
 	def_bool y
 
-config ARCH_HAS_CPU_AUTOPROBE
-	def_bool y
-
 config HAVE_SETUP_PER_CPU_AREA
 	def_bool y
 
diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
index e099f95..d86dc3d 100644
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -541,6 +541,13 @@ static __always_inline __pure bool _static_cpu_has_safe(u16 bit)
 #define static_cpu_has_bug(bit)	static_cpu_has((bit))
 #define boot_cpu_has_bug(bit)	cpu_has_bug(&boot_cpu_data, (bit))
 
+#define MAX_CPU_FEATURES	(NCAPINTS * 32)
+#define cpu_have_feature	boot_cpu_has
+
+#define CPU_FEATURE_TYPEFMT	"x86,ven%04Xfam%04Xmod%04X"
+#define CPU_FEATURE_TYPEVAL	boot_cpu_data.x86_vendor, boot_cpu_data.x86, \
+				boot_cpu_data.x86_model
+
 #endif /* defined(__KERNEL__) && !defined(__ASSEMBLY__) */
 
 #endif /* _ASM_X86_CPUFEATURE_H */
diff --git a/arch/x86/kernel/cpu/match.c b/arch/x86/kernel/cpu/match.c
index 3656537..afa9f0d 100644
--- a/arch/x86/kernel/cpu/match.c
+++ b/arch/x86/kernel/cpu/match.c
@@ -47,45 +47,3 @@ const struct x86_cpu_id *x86_match_cpu(const struct x86_cpu_id *match)
 	return NULL;
 }
 EXPORT_SYMBOL(x86_match_cpu);
-
-ssize_t arch_print_cpu_modalias(struct device *dev,
-				struct device_attribute *attr,
-				char *bufptr)
-{
-	int size = PAGE_SIZE;
-	int i, n;
-	char *buf = bufptr;
-
-	n = snprintf(buf, size, "x86cpu:vendor:%04X:family:%04X:"
-		     "model:%04X:feature:",
-		boot_cpu_data.x86_vendor,
-		boot_cpu_data.x86,
-		boot_cpu_data.x86_model);
-	size -= n;
-	buf += n;
-	size -= 1;
-	for (i = 0; i < NCAPINTS*32; i++) {
-		if (boot_cpu_has(i)) {
-			n = snprintf(buf, size, ",%04X", i);
-			if (n >= size) {
-				WARN(1, "x86 features overflow page\n");
-				break;
-			}
-			size -= n;
-			buf += n;
-		}
-	}
-	*buf++ = '\n';
-	return buf - bufptr;
-}
-
-int arch_cpu_uevent(struct device *dev, struct kobj_uevent_env *env)
-{
-	char *buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
-	if (buf) {
-		arch_print_cpu_modalias(NULL, NULL, buf);
-		add_uevent_var(env, "MODALIAS=%s", buf);
-		kfree(buf);
-	}
-	return 0;
-}
diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
index 3f0d373..8fa8dea 100644
--- a/drivers/base/Kconfig
+++ b/drivers/base/Kconfig
@@ -185,13 +185,8 @@ config GENERIC_CPU_DEVICES
 	bool
 	default n
 
-config HAVE_CPU_AUTOPROBE
-	def_bool ARCH_HAS_CPU_AUTOPROBE
-
 config GENERIC_CPU_AUTOPROBE
 	bool
-	depends on !ARCH_HAS_CPU_AUTOPROBE
-	select HAVE_CPU_AUTOPROBE
 
 config SOC_BUS
 	bool
diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
index 8a38bf8..006b1bc 100644
--- a/drivers/base/cpu.c
+++ b/drivers/base/cpu.c
@@ -287,7 +287,6 @@ static void cpu_device_release(struct device *dev)
 	 */
 }
 
-#ifdef CONFIG_HAVE_CPU_AUTOPROBE
 #ifdef CONFIG_GENERIC_CPU_AUTOPROBE
 static ssize_t print_cpu_modalias(struct device *dev,
 				  struct device_attribute *attr,
@@ -310,9 +309,6 @@ static ssize_t print_cpu_modalias(struct device *dev,
 	buf[n++] = '\n';
 	return n;
 }
-#else
-#define print_cpu_modalias	arch_print_cpu_modalias
-#endif
 
 static int cpu_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
@@ -346,7 +342,7 @@ int register_cpu(struct cpu *cpu, int num)
 	cpu->dev.offline_disabled = !cpu->hotpluggable;
 	cpu->dev.offline = !cpu_online(num);
 	cpu->dev.of_node = of_get_cpu_node(num, NULL);
-#ifdef CONFIG_HAVE_CPU_AUTOPROBE
+#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
 	cpu->dev.bus->uevent = cpu_uevent;
 #endif
 	cpu->dev.groups = common_cpu_attr_groups;
@@ -370,7 +366,7 @@ struct device *get_cpu_device(unsigned cpu)
 }
 EXPORT_SYMBOL_GPL(get_cpu_device);
 
-#ifdef CONFIG_HAVE_CPU_AUTOPROBE
+#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
 static DEVICE_ATTR(modalias, 0444, print_cpu_modalias, NULL);
 #endif
 
@@ -384,7 +380,7 @@ static struct attribute *cpu_root_attrs[] = {
 	&cpu_attrs[2].attr.attr,
 	&dev_attr_kernel_max.attr,
 	&dev_attr_offline.attr,
-#ifdef CONFIG_HAVE_CPU_AUTOPROBE
+#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
 	&dev_attr_modalias.attr,
 #endif
 	NULL
diff --git a/include/linux/cpu.h b/include/linux/cpu.h
index 03e235ad..03e962e 100644
--- a/include/linux/cpu.h
+++ b/include/linux/cpu.h
@@ -46,13 +46,6 @@ extern ssize_t arch_cpu_release(const char *, size_t);
 #endif
 struct notifier_block;
 
-#ifdef CONFIG_ARCH_HAS_CPU_AUTOPROBE
-extern int arch_cpu_uevent(struct device *dev, struct kobj_uevent_env *env);
-extern ssize_t arch_print_cpu_modalias(struct device *dev,
-				       struct device_attribute *attr,
-				       char *bufptr);
-#endif
-
 /*
  * CPU notifier priorities.
  */
diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c
index 8a69005..5fdad83 100644
--- a/scripts/mod/file2alias.c
+++ b/scripts/mod/file2alias.c
@@ -1110,7 +1110,7 @@ static int do_amba_entry(const char *filename,
 }
 ADD_TO_DEVTABLE("amba", amba_id, do_amba_entry);
 
-/* LOOKS like x86cpu:vendor:VVVV:family:FFFF:model:MMMM:feature:*,FEAT,*
+/* LOOKS like cpu:type:x86,venVVVVfamFFFFmodMMMM:feature:*,FEAT,*
  * All fields are numbers. It would be nicer to use strings for vendor
  * and feature, but getting those out of the build system here is too
  * complicated.
@@ -1124,10 +1124,10 @@ static int do_x86cpu_entry(const char *filename, void *symval,
 	DEF_FIELD(symval, x86_cpu_id, model);
 	DEF_FIELD(symval, x86_cpu_id, vendor);
 
-	strcpy(alias, "x86cpu:");
-	ADD(alias, "vendor:",  vendor != X86_VENDOR_ANY, vendor);
-	ADD(alias, ":family:", family != X86_FAMILY_ANY, family);
-	ADD(alias, ":model:",  model  != X86_MODEL_ANY,  model);
+	strcpy(alias, "cpu:type:x86,");
+	ADD(alias, "ven", vendor != X86_VENDOR_ANY, vendor);
+	ADD(alias, "fam", family != X86_FAMILY_ANY, family);
+	ADD(alias, "mod", model  != X86_MODEL_ANY,  model);
 	strcat(alias, ":feature:*");
 	if (feature != X86_FEATURE_ANY)
 		sprintf(alias + strlen(alias), "%04X*", feature);
-- 
1.8.3.2

Re: [PATCH v2 0/2] generic CPU feature based udev module autoprobing

[Ard Biesheuvel]

Ping?

On 8 February 2014 13:34, Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote:
> This series implements a generic way to wire up udev module autoprobing to
> optional CPU features.
>
> Patch #1 implements the actual generic part. It relies on the include file
> <asm/cpufeature.h> to be supplied by the architecture to map CPU features to
> the number based scheme used by modalias.
>
> Patch #2 aligns x86 with the generic code. As x86 allows matching on CPU vendor,
> family and model IDs, it still retains much of the original code for creating
> the module metadata.
>
> Changes since v1:
> - squashed into 2 patches, all the generic bits are now added in patch #1 and
>   all alignment of the x86 code with the newly introduced generic code is done
>   in patch #2
> - add more elaborate commit message for patch #1
> - added hpa's ack on patch #2
>
> Ard Biesheuvel (2):
>   cpu: add generic support for CPU feature based module autoloading
>   x86: align x86 arch with generic CPU modalias handling
>
>  arch/x86/Kconfig                  |  4 +--
>  arch/x86/include/asm/cpufeature.h |  7 +++++
>  arch/x86/kernel/cpu/match.c       | 42 ---------------------------
>  drivers/base/Kconfig              |  3 ++
>  drivers/base/cpu.c                | 46 ++++++++++++++++++++++++++----
>  include/linux/cpu.h               |  7 -----
>  include/linux/cpufeature.h        | 60 +++++++++++++++++++++++++++++++++++++++
>  include/linux/mod_devicetable.h   |  9 ++++++
>  scripts/mod/devicetable-offsets.c |  3 ++
>  scripts/mod/file2alias.c          | 20 +++++++++----
>  10 files changed, 139 insertions(+), 62 deletions(-)
>  create mode 100644 include/linux/cpufeature.h
>
> --
> 1.8.3.2
>

Re: [PATCH v2 0/2] generic CPU feature based udev module autoprobing

[Ard Biesheuvel]

Ping?

On 8 February 2014 13:34, Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote:
> This series implements a generic way to wire up udev module autoprobing to
> optional CPU features.
>
> Patch #1 implements the actual generic part. It relies on the include file
> <asm/cpufeature.h> to be supplied by the architecture to map CPU features to
> the number based scheme used by modalias.
>
> Patch #2 aligns x86 with the generic code. As x86 allows matching on CPU vendor,
> family and model IDs, it still retains much of the original code for creating
> the module metadata.
>
> Changes since v1:
> - squashed into 2 patches, all the generic bits are now added in patch #1 and
>   all alignment of the x86 code with the newly introduced generic code is done
>   in patch #2
> - add more elaborate commit message for patch #1
> - added hpa's ack on patch #2
>
> Ard Biesheuvel (2):
>   cpu: add generic support for CPU feature based module autoloading
>   x86: align x86 arch with generic CPU modalias handling
>
>  arch/x86/Kconfig                  |  4 +--
>  arch/x86/include/asm/cpufeature.h |  7 +++++
>  arch/x86/kernel/cpu/match.c       | 42 ---------------------------
>  drivers/base/Kconfig              |  3 ++
>  drivers/base/cpu.c                | 46 ++++++++++++++++++++++++++----
>  include/linux/cpu.h               |  7 -----
>  include/linux/cpufeature.h        | 60 +++++++++++++++++++++++++++++++++++++++
>  include/linux/mod_devicetable.h   |  9 ++++++
>  scripts/mod/devicetable-offsets.c |  3 ++
>  scripts/mod/file2alias.c          | 20 +++++++++----
>  10 files changed, 139 insertions(+), 62 deletions(-)
>  create mode 100644 include/linux/cpufeature.h
>
> --
> 1.8.3.2
>

Re: [PATCH v2 0/2] generic CPU feature based udev module autoprobing

[gregkh]

On Sun, Feb 16, 2014 at 03:40:04PM +0100, Ard Biesheuvel wrote:
> Ping?

Sorry, still digging out from the -rc1 backlog.  Give me a few days,
Monday is a holliday in the US.

greg k-h

Re: [PATCH v2 0/2] generic CPU feature based udev module autoprobing

[gregkh]

On Sun, Feb 16, 2014 at 03:40:04PM +0100, Ard Biesheuvel wrote:
> Ping?

Sorry, still digging out from the -rc1 backlog.  Give me a few days,
Monday is a holliday in the US.

greg k-h

Re: [PATCH v2 0/2] generic CPU feature based udev module autoprobing

[Ard Biesheuvel]

On 16 February 2014 17:39, gregkh@linuxfoundation.org
<gregkh@linuxfoundation.org> wrote:
> On Sun, Feb 16, 2014 at 03:40:04PM +0100, Ard Biesheuvel wrote:
>> Ping?
>
> Sorry, still digging out from the -rc1 backlog.  Give me a few days,
> Monday is a holliday in the US.
>

Yes, please, whenever you have some time.

Regards,
Ard.

Re: [PATCH v2 0/2] generic CPU feature based udev module autoprobing

[gregkh]

On Sun, Feb 16, 2014 at 06:11:27PM +0100, Ard Biesheuvel wrote:
> On 16 February 2014 17:39, gregkh@linuxfoundation.org
> <gregkh@linuxfoundation.org> wrote:
> > On Sun, Feb 16, 2014 at 03:40:04PM +0100, Ard Biesheuvel wrote:
> >> Ping?
> >
> > Sorry, still digging out from the -rc1 backlog.  Give me a few days,
> > Monday is a holliday in the US.
> >
> 
> Yes, please, whenever you have some time.

Both now applied to my tree.

greg k-h