x86/speculation/taa: Add sysfs reporting for TSX Async Abort

commit 6608b45ac5ecb56f9e171252229c39580cc85f0f upstream.

Add the sysfs reporting file for TSX Async Abort. It exposes the
vulnerability and the mitigation state similar to the existing files for
the other hardware vulnerabilities.

Sysfs file path is:
/sys/devices/system/cpu/vulnerabilities/tsx_async_abort

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>
Tested-by: Neelima Krishnan <neelima.krishnan@intel.com>
Reviewed-by: Mark Gross <mgross@linux.intel.com>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 6f347f9a3525201567169618219dafee5a98e0e2..696f9ebf9dd59d471797d896a6f10b042dae62af 100644 (file)
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -1365,6 +1365,21 @@ static ssize_t mds_show_state(char *buf)
                       sched_smt_active() ? "vulnerable" : "disabled");
 }
 
+static ssize_t tsx_async_abort_show_state(char *buf)
+{
+       if ((taa_mitigation == TAA_MITIGATION_TSX_DISABLED) ||
+           (taa_mitigation == TAA_MITIGATION_OFF))
+               return sprintf(buf, "%s\n", taa_strings[taa_mitigation]);
+
+       if (boot_cpu_has(X86_FEATURE_HYPERVISOR)) {
+               return sprintf(buf, "%s; SMT Host state unknown\n",
+                              taa_strings[taa_mitigation]);
+       }
+
+       return sprintf(buf, "%s; SMT %s\n", taa_strings[taa_mitigation],
+                      sched_smt_active() ? "vulnerable" : "disabled");
+}
+
 static char *stibp_state(void)
 {
        if (spectre_v2_enabled == SPECTRE_V2_IBRS_ENHANCED)
@@ -1430,6 +1445,9 @@ static ssize_t cpu_show_common(struct device *dev, struct device_attribute *attr
        case X86_BUG_MDS:
                return mds_show_state(buf);
 
+       case X86_BUG_TAA:
+               return tsx_async_abort_show_state(buf);
+
        default:
                break;
        }
@@ -1466,4 +1484,9 @@ ssize_t cpu_show_mds(struct device *dev, struct device_attribute *attr, char *bu
 {
        return cpu_show_common(dev, attr, buf, X86_BUG_MDS);
 }
+
+ssize_t cpu_show_tsx_async_abort(struct device *dev, struct device_attribute *attr, char *buf)
+{
+       return cpu_show_common(dev, attr, buf, X86_BUG_TAA);
+}
 #endif

diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
index 2f22e8960d8a9767f85adfdf9235f040cd01c1c1..3512d0df4abcdb4577fa19815162fe1d003c5777 100644 (file)
--- a/drivers/base/cpu.c
+++ b/drivers/base/cpu.c
@@ -456,12 +456,20 @@ ssize_t __weak cpu_show_mds(struct device *dev,
        return sprintf(buf, "Not affected\n");
 }
 
+ssize_t __weak cpu_show_tsx_async_abort(struct device *dev,
+                                       struct device_attribute *attr,
+                                       char *buf)
+{
+       return sprintf(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);
 static DEVICE_ATTR(spec_store_bypass, 0444, cpu_show_spec_store_bypass, NULL);
 static DEVICE_ATTR(l1tf, 0444, cpu_show_l1tf, NULL);
 static DEVICE_ATTR(mds, 0444, cpu_show_mds, NULL);
+static DEVICE_ATTR(tsx_async_abort, 0444, cpu_show_tsx_async_abort, NULL);
 
 static struct attribute *cpu_root_vulnerabilities_attrs[] = {
        &dev_attr_meltdown.attr,
@@ -470,6 +478,7 @@ static struct attribute *cpu_root_vulnerabilities_attrs[] = {
        &dev_attr_spec_store_bypass.attr,
        &dev_attr_l1tf.attr,
        &dev_attr_mds.attr,
+       &dev_attr_tsx_async_abort.attr,
        NULL
 };
 

diff --git a/include/linux/cpu.h b/include/linux/cpu.h
index 356c94d46b3a0be0b7199973d45e5abce5a22556..47ee4540e636c7d596ebf418a0a1ce530198aae7 100644 (file)
--- a/include/linux/cpu.h
+++ b/include/linux/cpu.h
@@ -51,6 +51,9 @@ extern ssize_t cpu_show_l1tf(struct device *dev,
                             struct device_attribute *attr, char *buf);
 extern ssize_t cpu_show_mds(struct device *dev,
                            struct device_attribute *attr, char *buf);
+extern ssize_t cpu_show_tsx_async_abort(struct device *dev,
+                                       struct device_attribute *attr,
+                                       char *buf);
 
 #ifdef CONFIG_HOTPLUG_CPU
 extern void unregister_cpu(struct cpu *cpu);