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Subject[PATCH 1/3] cpuinfo: add sysfs based arch independent cpuinfo framework
Date
From: Felix Schnizlein <fschnizlein@suse.de>

Create a new sysfs attribute group called 'info' for each
online cpu. The cleaned up cpuinfo shows up in a sysfs
subdirectory here: /sys/devices/system/cpu/cpu#/info.

Define preprocessor macros (CPUINFO_DEFINE_* and CPUINFO_ATTR) to make
defining new sysfs attributes for cpuinfo more easy.

Add basic documentation for the info sysfs tree.

Signed-off-by: Felix Schnizlein <fschnizlein@suse.com>
Signed-off-by: Thomas Renninger <trenn@suse.de>
---
Documentation/ABI/testing/sysfs-devices-system-cpu | 7 ++++
arch/Kconfig | 11 +++++
drivers/base/Makefile | 1 +
drivers/base/cpuinfo.c | 48 ++++++++++++++++++++++
include/linux/cpuhotplug.h | 1 +
include/linux/cpuinfo.h | 43 +++++++++++++++++++
6 files changed, 111 insertions(+)
create mode 100644 drivers/base/cpuinfo.c
create mode 100644 include/linux/cpuinfo.h

diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu
index fc20cde63d1e..84c324773b36 100644
--- a/Documentation/ABI/testing/sysfs-devices-system-cpu
+++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
@@ -574,3 +574,10 @@ Description: Secure Virtual Machine
If 1, it means the system is using the Protected Execution
Facility in POWER9 and newer processors. i.e., it is a Secure
Virtual Machine.
+
+What: /sys/devices/system/cpu/cpu#/info/
+Date: June 2019
+Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
+Description: Various information about the online cpu. Which attributes are
+ available depends on the architecture, kernel configuration and
+ cpu model.
diff --git a/arch/Kconfig b/arch/Kconfig
index 48b5e103bdb0..39015570b1ca 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -882,6 +882,17 @@ config STRICT_MODULE_RWX
and non-text memory will be made non-executable. This provides
protection against certain security exploits (e.g. writing to text)

+config CPUINFO_SYSFS
+ bool "Provides processor information in sysfs. Successor of /proc/cpuinfo"
+ def_bool y
+ depends on HAVE_CPUINFO_SYSFS
+ help
+ Provides architecture specific processor information in /sys/devices/system/cpu/info
+ Use this instead of /proc/cpuinfo
+
+config HAVE_CPUINFO_SYSFS
+ bool
+
# select if the architecture provides an asm/dma-direct.h header
config ARCH_HAS_PHYS_TO_DMA
bool
diff --git a/drivers/base/Makefile b/drivers/base/Makefile
index 4db2e8f1a1f4..68701f94774c 100644
--- a/drivers/base/Makefile
+++ b/drivers/base/Makefile
@@ -24,6 +24,7 @@ obj-$(CONFIG_PINCTRL) += pinctrl.o
obj-$(CONFIG_DEV_COREDUMP) += devcoredump.o
obj-$(CONFIG_GENERIC_MSI_IRQ_DOMAIN) += platform-msi.o
obj-$(CONFIG_GENERIC_ARCH_TOPOLOGY) += arch_topology.o
+obj-$(CONFIG_CPUINFO_SYSFS) += cpuinfo.o

obj-y += test/

diff --git a/drivers/base/cpuinfo.c b/drivers/base/cpuinfo.c
new file mode 100644
index 000000000000..09b554d09bfa
--- /dev/null
+++ b/drivers/base/cpuinfo.c
@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) 2017 SUSE Linux GmbH
+ * Written by: Felix Schnizlein <fschnizlein@suse.com>
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ */
+
+#include <linux/cpu.h>
+#include <linux/module.h>
+#include <linux/cpuinfo.h>
+
+static struct attribute_group cpuinfo_attr_group = {
+ .attrs = cpuinfo_attrs,
+ .name = "info"
+};
+
+static int cpuinfo_add_dev(unsigned int cpu)
+{
+ struct device *dev = get_cpu_device(cpu);
+
+ return sysfs_create_group(&dev->kobj, &cpuinfo_attr_group);
+}
+
+static int cpuinfo_remove_dev(unsigned int cpu)
+{
+ struct device *dev = get_cpu_device(cpu);
+
+ sysfs_remove_group(&dev->kobj, &cpuinfo_attr_group);
+ return 0;
+}
+
+static int cpuinfo_sysfs_init(void)
+{
+ return cpuhp_setup_state(CPUHP_CPUINFO_PREPARE,
+ "base/cpuinfo:prepare",
+ cpuinfo_add_dev,
+ cpuinfo_remove_dev);
+}
+
+device_initcall(cpuinfo_sysfs_init);
diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index e51ee772b9f5..2c4c59304bdb 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -78,6 +78,7 @@ enum cpuhp_state {
CPUHP_SH_SH3X_PREPARE,
CPUHP_NET_FLOW_PREPARE,
CPUHP_TOPOLOGY_PREPARE,
+ CPUHP_CPUINFO_PREPARE,
CPUHP_NET_IUCV_PREPARE,
CPUHP_ARM_BL_PREPARE,
CPUHP_TRACE_RB_PREPARE,
diff --git a/include/linux/cpuinfo.h b/include/linux/cpuinfo.h
new file mode 100644
index 000000000000..112ff76d64d5
--- /dev/null
+++ b/include/linux/cpuinfo.h
@@ -0,0 +1,43 @@
+/*
+ * Copyright (C) 2017 SUSE Linux GmbH
+ * Written by: Felix Schnizlein <fschnizlein@suse.com>
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ */
+#ifndef _LINUX_CPUINFO_H
+#define _LINUX_CPUINFO_H
+
+#ifdef CONFIG_HAVE_CPUINFO_SYSFS
+extern struct attribute *cpuinfo_attrs[];
+
+#define CPUINFO_DEFINE_ATTR(name, format) \
+static ssize_t name##_show(struct device *dev, \
+ struct device_attribute *attr, \
+ char *buf) \
+{ \
+ return sprintf(buf, format"\n", cpuinfo_##name(dev->id)); \
+} \
+static DEVICE_ATTR_RO(name)
+
+
+#define CPUINFO_DEFINE_ATTR_FUNC(name) \
+static ssize_t name##_show(struct device *dev, \
+ struct device_attribute *attr, \
+ char *buf) \
+{ \
+ return cpuinfo_##name(dev->id, buf); \
+} \
+static DEVICE_ATTR_RO(name)
+
+
+#define CPUINFO_ATTR(name) (&dev_attr_##name.attr)
+#endif /* CONFIG_HAVE_CPUINFO_SYSFS */
+
+#endif /* _LINUX_CPUINFO_H */
--
2.16.4
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