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authorPawan Gupta <pawan.kumar.gupta@linux.intel.com>2022-05-19 20:32:13 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2022-06-16 13:00:52 +0200
commit8acd4bf9427eaf18a801db3f2508a2d89914d51d (patch)
tree4e6b076b18c41df20364eb7bd9963ed9b769e07c
parent6ecdbc9dc777a5b66a9ec293af88ab330dd644a2 (diff)
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x86/speculation/mmio: Add sysfs reporting for Processor MMIO Stale Data
commit 8d50cdf8b8341770bc6367bce40c0c1bb0e1d5b3 upstream Add the sysfs reporting file for Processor MMIO Stale Data vulnerability. It exposes the vulnerability and mitigation state similar to the existing files for the other hardware vulnerabilities. Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--Documentation/ABI/testing/sysfs-devices-system-cpu1
-rw-r--r--arch/x86/kernel/cpu/bugs.c22
-rw-r--r--drivers/base/cpu.c8
-rw-r--r--include/linux/cpu.h3
4 files changed, 34 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu
index a5225df4a070..22c078d1a23b 100644
--- a/Documentation/ABI/testing/sysfs-devices-system-cpu
+++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
@@ -361,6 +361,7 @@ What: /sys/devices/system/cpu/vulnerabilities
/sys/devices/system/cpu/vulnerabilities/srbds
/sys/devices/system/cpu/vulnerabilities/tsx_async_abort
/sys/devices/system/cpu/vulnerabilities/itlb_multihit
+ /sys/devices/system/cpu/vulnerabilities/mmio_stale_data
Date: January 2018
Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
Description: Information about CPU vulnerabilities
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index a76c87cc27b0..7ad272832c97 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -1809,6 +1809,20 @@ static ssize_t tsx_async_abort_show_state(char *buf)
sched_smt_active() ? "vulnerable" : "disabled");
}
+static ssize_t mmio_stale_data_show_state(char *buf)
+{
+ if (mmio_mitigation == MMIO_MITIGATION_OFF)
+ return sysfs_emit(buf, "%s\n", mmio_strings[mmio_mitigation]);
+
+ if (boot_cpu_has(X86_FEATURE_HYPERVISOR)) {
+ return sysfs_emit(buf, "%s; SMT Host state unknown\n",
+ mmio_strings[mmio_mitigation]);
+ }
+
+ return sysfs_emit(buf, "%s; SMT %s\n", mmio_strings[mmio_mitigation],
+ sched_smt_active() ? "vulnerable" : "disabled");
+}
+
static char *stibp_state(void)
{
if (spectre_v2_in_eibrs_mode(spectre_v2_enabled))
@@ -1906,6 +1920,9 @@ static ssize_t cpu_show_common(struct device *dev, struct device_attribute *attr
case X86_BUG_SRBDS:
return srbds_show_state(buf);
+ case X86_BUG_MMIO_STALE_DATA:
+ return mmio_stale_data_show_state(buf);
+
default:
break;
}
@@ -1957,4 +1974,9 @@ ssize_t cpu_show_srbds(struct device *dev, struct device_attribute *attr, char *
{
return cpu_show_common(dev, attr, buf, X86_BUG_SRBDS);
}
+
+ssize_t cpu_show_mmio_stale_data(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ return cpu_show_common(dev, attr, buf, X86_BUG_MMIO_STALE_DATA);
+}
#endif
diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
index 100850398dd3..88f89a38588a 100644
--- a/drivers/base/cpu.c
+++ b/drivers/base/cpu.c
@@ -556,6 +556,12 @@ ssize_t __weak cpu_show_srbds(struct device *dev,
return sprintf(buf, "Not affected\n");
}
+ssize_t __weak cpu_show_mmio_stale_data(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return sysfs_emit(buf, "Not affected\n");
+}
+
static DEVICE_ATTR(meltdown, 0444, cpu_show_meltdown, NULL);
static DEVICE_ATTR(spectre_v1, 0444, cpu_show_spectre_v1, NULL);
static DEVICE_ATTR(spectre_v2, 0444, cpu_show_spectre_v2, NULL);
@@ -565,6 +571,7 @@ static DEVICE_ATTR(mds, 0444, cpu_show_mds, NULL);
static DEVICE_ATTR(tsx_async_abort, 0444, cpu_show_tsx_async_abort, NULL);
static DEVICE_ATTR(itlb_multihit, 0444, cpu_show_itlb_multihit, NULL);
static DEVICE_ATTR(srbds, 0444, cpu_show_srbds, NULL);
+static DEVICE_ATTR(mmio_stale_data, 0444, cpu_show_mmio_stale_data, NULL);
static struct attribute *cpu_root_vulnerabilities_attrs[] = {
&dev_attr_meltdown.attr,
@@ -576,6 +583,7 @@ static struct attribute *cpu_root_vulnerabilities_attrs[] = {
&dev_attr_tsx_async_abort.attr,
&dev_attr_itlb_multihit.attr,
&dev_attr_srbds.attr,
+ &dev_attr_mmio_stale_data.attr,
NULL
};
diff --git a/include/linux/cpu.h b/include/linux/cpu.h
index 673f21465377..6c1cb1f1bd4b 100644
--- a/include/linux/cpu.h
+++ b/include/linux/cpu.h
@@ -62,6 +62,9 @@ extern ssize_t cpu_show_tsx_async_abort(struct device *dev,
extern ssize_t cpu_show_itlb_multihit(struct device *dev,
struct device_attribute *attr, char *buf);
extern ssize_t cpu_show_srbds(struct device *dev, struct device_attribute *attr, char *buf);
+extern ssize_t cpu_show_mmio_stale_data(struct device *dev,
+ struct device_attribute *attr,
+ char *buf);
extern __printf(4, 5)
struct device *cpu_device_create(struct device *parent, void *drvdata,