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Subject[PATCH 2/3] x86 cpuinfo: implement sysfs nodes for x86
Date
From: Felix Schnizlein <fschnizlein@suse.de>

Enable sysfs cpuinfo for x86 based cpus.
Export often used cpu information to sysfs:
stepping, flags, bugs, bogomips, family, vendor_id,
model, and model_name are exported.

Sysfs documentation is updated to reflect changes.

Example (on a kvm instance running no an intel cpu):
/sys/devices/system/cpu/cpu1/info/:[0]# head *
==> bogomips <==
5187.72

==> bugs <==
cpu_meltdown spectre_v1 spectre_v2 spec_store_bypass l1tf mds swapgs itlb_multihit

==> cpu_family <==
6

==> flags <==
fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ss syscall nx pdpe1gb rdtscp lm constant_tsc rep_good nopl xtopology cpuid tsc_known_freq pni pclmulqdq ssse3 fma cx16 pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand hypervisor lahf_lm abm cpuid_fault invpcid_single pti ssbd ibrs ibpb fsgsbase tsc_adjust bmi1 avx2 smep bmi2 erms invpcid xsaveopt arat umip

==> model <==
60

==> model_name <==
Intel Core Processor (Haswell, no TSX, IBRS)

==> stepping <==
1

==> vendor_id <==
GenuineIntel

Signed-off-by: Felix Schnizlein <fschnizlein@suse.com>
Signed-off-by: Thomas Renninger <trenn@suse.com>
---
Documentation/ABI/testing/sysfs-devices-system-cpu | 23 +++++
arch/x86/Kconfig | 1 +
arch/x86/kernel/Makefile | 2 +
arch/x86/kernel/cpuinfo.c | 99 ++++++++++++++++++++++
4 files changed, 125 insertions(+)
create mode 100644 arch/x86/kernel/cpuinfo.c

diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu
index 84c324773b36..791390ab66d5 100644
--- a/Documentation/ABI/testing/sysfs-devices-system-cpu
+++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
@@ -581,3 +581,26 @@ 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.
+
+What: /sys/devices/system/cpu/cpu#/info/
+ /sys/devices/system/cpu/cpu#/info/vendor_id
+ /sys/devices/system/cpu/cpu#/info/cpu_family
+ /sys/devices/system/cpu/cpu#/info/model
+ /sys/devices/system/cpu/cpu#/info/model_name
+ /sys/devices/system/cpu/cpu#/info/stepping
+ /sys/devices/system/cpu/cpu#/info/flags
+ /sys/devices/system/cpu/cpu#/info/bugs
+ /sys/devices/system/cpu/cpu#/info/bogomips
+Date: June 2017
+Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
+Description: Expose information about x86 cpu information.
+
+ vendor_id,
+ cpu_family,
+ model,
+ model_name,
+ stepping: Cpu identification depending on each vendor
+
+ flags: Extended capabilities supported by the cpu
+ bugs: Known bugs by cpu
+ bogomips: calculated bogomips
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 8529a9dbd5ca..29fadd69d541 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -154,6 +154,7 @@ config X86
select HAVE_CMPXCHG_LOCAL
select HAVE_CONTEXT_TRACKING if X86_64
select HAVE_COPY_THREAD_TLS
+ select HAVE_CPUINFO_SYSFS if SYSFS
select HAVE_C_RECORDMCOUNT
select HAVE_DEBUG_KMEMLEAK
select HAVE_DMA_CONTIGUOUS
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index ccb13271895d..ccf1a338bc37 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -146,6 +146,8 @@ obj-$(CONFIG_UNWINDER_ORC) += unwind_orc.o
obj-$(CONFIG_UNWINDER_FRAME_POINTER) += unwind_frame.o
obj-$(CONFIG_UNWINDER_GUESS) += unwind_guess.o

+obj-$(CONFIG_CPUINFO_SYSFS) += cpuinfo.o
+
###
# 64 bit specific files
ifeq ($(CONFIG_X86_64),y)
diff --git a/arch/x86/kernel/cpuinfo.c b/arch/x86/kernel/cpuinfo.c
new file mode 100644
index 000000000000..3b772faf9f5f
--- /dev/null
+++ b/arch/x86/kernel/cpuinfo.c
@@ -0,0 +1,99 @@
+/*
+ * 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/cpuinfo.h>
+#include <linux/cpufreq.h>
+#include <linux/smp.h>
+
+static ssize_t cpuinfo_stepping(unsigned int c, char *buf)
+{
+ if (cpu_data(c).x86_stepping || cpu_data(c).cpuid_level >= 0)
+ return sprintf(buf, "%d\n", cpu_data(c).x86_stepping);
+ return sprintf(buf, "unknown\n");
+}
+
+static ssize_t cpuinfo_flags(unsigned int c, char *buf)
+{
+ struct cpuinfo_x86 *cpu = &cpu_data(c);
+ unsigned int i;
+ ssize_t len = 0;
+
+ for (i = 0; i < (32 * NCAPINTS); i++) {
+ if (cpu_has(cpu, i) && x86_cap_flags[i] != NULL)
+ len += sprintf(buf+len, len == 0 ? "%s" : " %s",
+ x86_cap_flags[i]);
+ }
+ if (!len)
+ return 0;
+ return len + sprintf(buf+len, "\n");
+}
+
+static ssize_t cpuinfo_bugs(unsigned int c, char *buf)
+{
+ struct cpuinfo_x86 *cpu = &cpu_data(c);
+ unsigned int i;
+ ssize_t len = 0;
+
+ for (i = 0; i < 32*NBUGINTS; i++) {
+ unsigned int bug_bit = 32*NCAPINTS + i;
+
+ if (cpu_has_bug(cpu, bug_bit) && x86_bug_flags[i])
+ len += sprintf(buf+len, len == 0 ? "%s" : " %s",
+ x86_bug_flags[i]);
+ }
+ if (!len)
+ return 0;
+ return len + sprintf(buf+len, "\n");
+}
+
+static ssize_t cpuinfo_bogomips(unsigned int c, char *buf)
+{
+ struct cpuinfo_x86 cpu = cpu_data(c);
+
+ return sprintf(buf, "%lu.%02lu\n", cpu.loops_per_jiffy / (500000 / HZ),
+ (cpu.loops_per_jiffy / (5000 / HZ)) % 100);
+}
+
+#define cpuinfo_cpu_family(cpu) cpu_data(cpu).x86
+#define cpuinfo_model(cpu) cpu_data(cpu).x86_model
+
+#define cpuinfo_vendor_id(cpu) cpu_data(cpu).x86_vendor_id[0] ?\
+ cpu_data(cpu).x86_vendor_id : "unknown"
+
+#define cpuinfo_model_name(cpu) cpu_data(cpu).x86_model_id[0] ? \
+ cpu_data(cpu).x86_model_id : "unknown"
+
+CPUINFO_DEFINE_ATTR(cpu_family, "%d");
+CPUINFO_DEFINE_ATTR(model, "%u");
+CPUINFO_DEFINE_ATTR(vendor_id, "%s");
+CPUINFO_DEFINE_ATTR(model_name, "%s");
+
+CPUINFO_DEFINE_ATTR_FUNC(stepping);
+CPUINFO_DEFINE_ATTR_FUNC(flags);
+CPUINFO_DEFINE_ATTR_FUNC(bugs);
+CPUINFO_DEFINE_ATTR_FUNC(bogomips);
+
+struct attribute *cpuinfo_attrs[] = {
+ CPUINFO_ATTR(vendor_id),
+ CPUINFO_ATTR(cpu_family),
+ CPUINFO_ATTR(model),
+ CPUINFO_ATTR(model_name),
+ CPUINFO_ATTR(stepping),
+ CPUINFO_ATTR(flags),
+ CPUINFO_ATTR(bugs),
+ CPUINFO_ATTR(bogomips),
+ NULL
+};
--
2.16.4
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