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Subject[PATCH 3/3] arm64 cpuinfo: implement sysfs nodes for arm64
Date
From: Felix Schnizlein <fschnizlein@suse.de>

Export all information from /proc/cpuinfo to sysfs:
implementer, architecture, variant, part, revision,
bogomips and flags are exported.

Example:
/sys/devices/system/cpu/cpu1/info/:[0]# head *
==> architecture <==
8

==> bogomips <==
40.00

==> flags <==
fp asimd evtstrm aes pmull sha1 sha2 crc32 cpuid asimdrdm

==> implementer <==
0x51

==> part <==
0xc00

==> revision <==
1

==> variant <==
0x0

Signed-off-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Felix Schnizlein <fschnizlein@suse.com>
---
Documentation/ABI/testing/sysfs-devices-system-cpu | 22 +++++++++
arch/arm64/Kconfig | 1 +
arch/arm64/kernel/cpuinfo.c | 55 ++++++++++++++++++++++
3 files changed, 78 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu
index 791390ab66d5..b6a167cd0beb 100644
--- a/Documentation/ABI/testing/sysfs-devices-system-cpu
+++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
@@ -604,3 +604,25 @@ Description: Expose information about x86 cpu information.
flags: Extended capabilities supported by the cpu
bugs: Known bugs by cpu
bogomips: calculated bogomips
+
+
+What: /sys/devices/system/cpu/cpu#/info/
+ /sys/devices/system/cpu/cpu#/info/implementer
+ /sys/devices/system/cpu/cpu#/info/architecture
+ /sys/devices/system/cpu/cpu#/info/variant
+ /sys/devices/system/cpu/cpu#/info/part
+ /sys/devices/system/cpu/cpu#/info/revision
+ /sys/devices/system/cpu/cpu#/info/flags
+ /sys/devices/system/cpu/cpu#/info/bogomips
+Date: August 2017
+Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
+Description: Expose information about arm64 cpu.
+
+ implementer,
+ architecture,
+ variant,
+ part,
+ revision: Cpu identification depending on each vendor
+
+ flags: Extended capabilities supported by the cpu
+ bogomips: calculated bogomips
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 43aa1de727f4..0e8f7733e8c3 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -169,6 +169,7 @@ config ARM64
select HAVE_KPROBES
select HAVE_KRETPROBES
select HAVE_GENERIC_VDSO
+ select HAVE_CPUINFO_SYSFS if SYSFS
select IOMMU_DMA if IOMMU_SUPPORT
select IRQ_DOMAIN
select IRQ_FORCED_THREADING
diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c
index 56bba746da1c..d142e2d37ead 100644
--- a/arch/arm64/kernel/cpuinfo.c
+++ b/arch/arm64/kernel/cpuinfo.c
@@ -24,6 +24,7 @@
#include <linux/sched.h>
#include <linux/smp.h>
#include <linux/delay.h>
+#include <linux/cpuinfo.h>

/*
* In case the boot CPU is hotpluggable, we record its initial state and
@@ -33,6 +34,8 @@
DEFINE_PER_CPU(struct cpuinfo_arm64, cpu_data);
static struct cpuinfo_arm64 boot_cpu_data;

+#define cpu_data(cpu) per_cpu(cpu_data, cpu)
+
static const char *icache_policy_str[] = {
[0 ... ICACHE_POLICY_PIPT] = "RESERVED/UNKNOWN",
[ICACHE_POLICY_VIPT] = "VIPT",
@@ -285,6 +288,58 @@ static int cpuid_cpu_offline(unsigned int cpu)
return 0;
}

+#ifdef CONFIG_HAVE_CPUINFO_SYSFS
+
+#define cpuinfo_implementer(cpu) MIDR_IMPLEMENTOR(cpu_data(cpu).reg_midr)
+#define cpuinfo_architecture(cpu) "8"
+#define cpuinfo_variant(cpu) MIDR_VARIANT(cpu_data(cpu).reg_midr)
+#define cpuinfo_part(cpu) MIDR_PARTNUM(cpu_data(cpu).reg_midr)
+#define cpuinfo_revision(cpu) MIDR_REVISION(cpu_data(cpu).reg_midr)
+
+static ssize_t cpuinfo_flags(unsigned int c, char *buf)
+{
+ unsigned int i;
+ ssize_t len = 0;
+
+ for (i = 0; hwcap_str[i]; i++) {
+ if (cpu_have_feature(i))
+ len += sprintf(buf+len, len == 0 ? "%s" : " %s",
+ hwcap_str[i]);
+ }
+ if (!len)
+ return 0;
+ return len + sprintf(buf+len, "\n");
+}
+
+static ssize_t cpuinfo_bogomips(unsigned int c, char *buf)
+{
+ return sprintf(buf, "%lu.%02lu\n", loops_per_jiffy / (500000 / HZ),
+ (loops_per_jiffy / (5000 / HZ)) % 100);
+
+}
+
+CPUINFO_DEFINE_ATTR(implementer, "0x%02x");
+CPUINFO_DEFINE_ATTR(architecture, "%s");
+CPUINFO_DEFINE_ATTR(variant, "0x%x");
+CPUINFO_DEFINE_ATTR(part, "0x%03x");
+CPUINFO_DEFINE_ATTR(revision, "%d");
+
+CPUINFO_DEFINE_ATTR_FUNC(bogomips);
+CPUINFO_DEFINE_ATTR_FUNC(flags);
+
+struct attribute *cpuinfo_attrs[] = {
+ CPUINFO_ATTR(implementer),
+ CPUINFO_ATTR(architecture),
+ CPUINFO_ATTR(variant),
+ CPUINFO_ATTR(part),
+ CPUINFO_ATTR(revision),
+ CPUINFO_ATTR(bogomips),
+ CPUINFO_ATTR(flags),
+ NULL
+};
+#endif /* CONFIG_HAVE_CPUINFO_SYSFS */
+
+
static int __init cpuinfo_regs_init(void)
{
int cpu, ret;
--
2.16.4
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