2 files changed, 93 insertions, 0 deletions

diff --git a/drivers/platform/x86/intel/ifs/ifs.h b/drivers/platform/x86/intel/ifs/ifs.h
index a7d87fb4c412..048131df13bc 100644
--- a/drivers/platform/x86/intel/ifs/ifs.h
+++ b/drivers/platform/x86/intel/ifs/ifs.h
@@ -127,6 +127,7 @@
 #include <linux/device.h>
 #include <linux/miscdevice.h>
 
+#define MSR_ARRAY_BIST				0x00000105
 #define MSR_COPY_SCAN_HASHES			0x000002c2
 #define MSR_SCAN_HASHES_STATUS			0x000002c3
 #define MSR_AUTHENTICATE_AND_COPY_CHUNK		0x000002c4
@@ -192,6 +193,17 @@ union ifs_status {
 	};
 };
 
+/* MSR_ARRAY_BIST bit fields */
+union ifs_array {
+	u64	data;
+	struct {
+		u32	array_bitmask;
+		u16	array_bank;
+		u16	rsvd			:15;
+		u16	ctrl_result		:1;
+	};
+};
+
 /*
  * Driver populated error-codes
  * 0xFD: Test timed out before completing all the chunks.
diff --git a/drivers/platform/x86/intel/ifs/runtest.c b/drivers/platform/x86/intel/ifs/runtest.c
index 323752fe5034..1061eb7ec399 100644
--- a/drivers/platform/x86/intel/ifs/runtest.c
+++ b/drivers/platform/x86/intel/ifs/runtest.c
@@ -229,6 +229,85 @@ static void ifs_test_core(int cpu, struct device *dev)
 	}
 }
 
+#define SPINUNIT 100 /* 100 nsec */
+static atomic_t array_cpus_out;
+
+/*
+ * Simplified cpu sibling rendezvous loop based on microcode loader __wait_for_cpus()
+ */
+static void wait_for_sibling_cpu(atomic_t *t, long long timeout)
+{
+	int cpu = smp_processor_id();
+	const struct cpumask *smt_mask = cpu_smt_mask(cpu);
+	int all_cpus = cpumask_weight(smt_mask);
+
+	atomic_inc(t);
+	while (atomic_read(t) < all_cpus) {
+		if (timeout < SPINUNIT)
+			return;
+		ndelay(SPINUNIT);
+		timeout -= SPINUNIT;
+		touch_nmi_watchdog();
+	}
+}
+
+static int do_array_test(void *data)
+{
+	union ifs_array *command = data;
+	int cpu = smp_processor_id();
+	int first;
+
+	/*
+	 * Only one logical CPU on a core needs to trigger the Array test via MSR write.
+	 */
+	first = cpumask_first(cpu_smt_mask(cpu));
+
+	if (cpu == first) {
+		wrmsrl(MSR_ARRAY_BIST, command->data);
+		/* Pass back the result of the test */
+		rdmsrl(MSR_ARRAY_BIST, command->data);
+	}
+
+	/* Tests complete faster if the sibling is spinning here */
+	wait_for_sibling_cpu(&array_cpus_out, NSEC_PER_SEC);
+
+	return 0;
+}
+
+static void ifs_array_test_core(int cpu, struct device *dev)
+{
+	union ifs_array command = {};
+	bool timed_out = false;
+	struct ifs_data *ifsd;
+	unsigned long timeout;
+
+	ifsd = ifs_get_data(dev);
+
+	command.array_bitmask = ~0U;
+	timeout = jiffies + HZ / 2;
+
+	do {
+		if (time_after(jiffies, timeout)) {
+			timed_out = true;
+			break;
+		}
+		atomic_set(&array_cpus_out, 0);
+		stop_core_cpuslocked(cpu, do_array_test, &command);
+
+		if (command.ctrl_result)
+			break;
+	} while (command.array_bitmask);
+
+	ifsd->scan_details = command.data;
+
+	if (command.ctrl_result)
+		ifsd->status = SCAN_TEST_FAIL;
+	else if (timed_out || command.array_bitmask)
+		ifsd->status = SCAN_NOT_TESTED;
+	else
+		ifsd->status = SCAN_TEST_PASS;
+}
+
 /*
  * Initiate per core test. It wakes up work queue threads on the target cpu and
  * its sibling cpu. Once all sibling threads wake up, the scan test gets executed and
@@ -256,6 +335,8 @@ int do_core_test(int cpu, struct device *dev)
 		ifs_test_core(cpu, dev);
 		break;
 	case IFS_TYPE_ARRAY_BIST:
+		ifs_array_test_core(cpu, dev);
+		break;
 	default:
 		return -EINVAL;
 	}