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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 8b219d30c3810d4b5554332b35e7efa7aea9b927..507aa25176c15ae5ea5510377ef17e31ad6010ff 100644 (file)
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -1408,6 +1408,21 @@ 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)
@@ -1473,6 +1488,9 @@ 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;
        }
@@ -1509,4 +1527,9 @@ 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 32b52e6bd13b73464eeadfc3361eaa1cd3098bd9..0cd78375cd5e982f0181d4a3a85b7d48c4e96740 100644 (file)
--- a/drivers/base/cpu.c
+++ b/drivers/base/cpu.c
@@ -539,12 +539,20 @@ 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,
@@ -553,6 +561,7 @@ 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 efc48efb0ec6ae104f8cfb389423bd329e4c3562..851208e7aa131ed821cf1c8a0b035f4a56d8a2ec 100644 (file)
--- a/include/linux/cpu.h
+++ b/include/linux/cpu.h
@@ -59,6 +59,9 @@ 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);
 
 extern __printf(4, 5)
 struct device *cpu_device_create(struct device *parent, void *drvdata,