1 files changed, 252 insertions, 0 deletions
diff --git a/drivers/platform/x86/intel/ifs/runtest.c b/drivers/platform/x86/intel/ifs/runtest.c
new file mode 100644
index 000000000000..b2ca2bb4501f
--- /dev/null
+++ b/drivers/platform/x86/intel/ifs/runtest.c
@@ -0,0 +1,252 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright(c) 2022 Intel Corporation. */
+
+#include <linux/cpu.h>
+#include <linux/delay.h>
+#include <linux/fs.h>
+#include <linux/nmi.h>
+#include <linux/slab.h>
+#include <linux/stop_machine.h>
+
+#include "ifs.h"
+
+/*
+ * Note all code and data in this file is protected by
+ * ifs_sem. On HT systems all threads on a core will
+ * execute together, but only the first thread on the
+ * core will update results of the test.
+ */
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/intel_ifs.h>
+
+/* Max retries on the same chunk */
+#define MAX_IFS_RETRIES  5
+
+/*
+ * Number of TSC cycles that a logical CPU will wait for the other
+ * logical CPU on the core in the WRMSR(ACTIVATE_SCAN).
+ */
+#define IFS_THREAD_WAIT 100000
+
+enum ifs_status_err_code {
+	IFS_NO_ERROR				= 0,
+	IFS_OTHER_THREAD_COULD_NOT_JOIN		= 1,
+	IFS_INTERRUPTED_BEFORE_RENDEZVOUS	= 2,
+	IFS_POWER_MGMT_INADEQUATE_FOR_SCAN	= 3,
+	IFS_INVALID_CHUNK_RANGE			= 4,
+	IFS_MISMATCH_ARGUMENTS_BETWEEN_THREADS	= 5,
+	IFS_CORE_NOT_CAPABLE_CURRENTLY		= 6,
+	IFS_UNASSIGNED_ERROR_CODE		= 7,
+	IFS_EXCEED_NUMBER_OF_THREADS_CONCURRENT	= 8,
+	IFS_INTERRUPTED_DURING_EXECUTION	= 9,
+};
+
+static const char * const scan_test_status[] = {
+	[IFS_NO_ERROR] = "SCAN no error",
+	[IFS_OTHER_THREAD_COULD_NOT_JOIN] = "Other thread could not join.",
+	[IFS_INTERRUPTED_BEFORE_RENDEZVOUS] = "Interrupt occurred prior to SCAN coordination.",
+	[IFS_POWER_MGMT_INADEQUATE_FOR_SCAN] =
+	"Core Abort SCAN Response due to power management condition.",
+	[IFS_INVALID_CHUNK_RANGE] = "Non valid chunks in the range",
+	[IFS_MISMATCH_ARGUMENTS_BETWEEN_THREADS] = "Mismatch in arguments between threads T0/T1.",
+	[IFS_CORE_NOT_CAPABLE_CURRENTLY] = "Core not capable of performing SCAN currently",
+	[IFS_UNASSIGNED_ERROR_CODE] = "Unassigned error code 0x7",
+	[IFS_EXCEED_NUMBER_OF_THREADS_CONCURRENT] =
+	"Exceeded number of Logical Processors (LP) allowed to run Scan-At-Field concurrently",
+	[IFS_INTERRUPTED_DURING_EXECUTION] = "Interrupt occurred prior to SCAN start",
+};
+
+static void message_not_tested(struct device *dev, int cpu, union ifs_status status)
+{
+	if (status.error_code < ARRAY_SIZE(scan_test_status)) {
+		dev_info(dev, "CPU(s) %*pbl: SCAN operation did not start. %s\n",
+			 cpumask_pr_args(cpu_smt_mask(cpu)),
+			 scan_test_status[status.error_code]);
+	} else if (status.error_code == IFS_SW_TIMEOUT) {
+		dev_info(dev, "CPU(s) %*pbl: software timeout during scan\n",
+			 cpumask_pr_args(cpu_smt_mask(cpu)));
+	} else if (status.error_code == IFS_SW_PARTIAL_COMPLETION) {
+		dev_info(dev, "CPU(s) %*pbl: %s\n",
+			 cpumask_pr_args(cpu_smt_mask(cpu)),
+			 "Not all scan chunks were executed. Maximum forward progress retries exceeded");
+	} else {
+		dev_info(dev, "CPU(s) %*pbl: SCAN unknown status %llx\n",
+			 cpumask_pr_args(cpu_smt_mask(cpu)), status.data);
+	}
+}
+
+static void message_fail(struct device *dev, int cpu, union ifs_status status)
+{
+	/*
+	 * control_error is set when the microcode runs into a problem
+	 * loading the image from the reserved BIOS memory, or it has
+	 * been corrupted. Reloading the image may fix this issue.
+	 */
+	if (status.control_error) {
+		dev_err(dev, "CPU(s) %*pbl: could not execute from loaded scan image\n",
+			cpumask_pr_args(cpu_smt_mask(cpu)));
+	}
+
+	/*
+	 * signature_error is set when the output from the scan chains does not
+	 * match the expected signature. This might be a transient problem (e.g.
+	 * due to a bit flip from an alpha particle or neutron). If the problem
+	 * repeats on a subsequent test, then it indicates an actual problem in
+	 * the core being tested.
+	 */
+	if (status.signature_error) {
+		dev_err(dev, "CPU(s) %*pbl: test signature incorrect.\n",
+			cpumask_pr_args(cpu_smt_mask(cpu)));
+	}
+}
+
+static bool can_restart(union ifs_status status)
+{
+	enum ifs_status_err_code err_code = status.error_code;
+
+	/* Signature for chunk is bad, or scan test failed */
+	if (status.signature_error || status.control_error)
+		return false;
+
+	switch (err_code) {
+	case IFS_NO_ERROR:
+	case IFS_OTHER_THREAD_COULD_NOT_JOIN:
+	case IFS_INTERRUPTED_BEFORE_RENDEZVOUS:
+	case IFS_POWER_MGMT_INADEQUATE_FOR_SCAN:
+	case IFS_EXCEED_NUMBER_OF_THREADS_CONCURRENT:
+	case IFS_INTERRUPTED_DURING_EXECUTION:
+		return true;
+	case IFS_INVALID_CHUNK_RANGE:
+	case IFS_MISMATCH_ARGUMENTS_BETWEEN_THREADS:
+	case IFS_CORE_NOT_CAPABLE_CURRENTLY:
+	case IFS_UNASSIGNED_ERROR_CODE:
+		break;
+	}
+	return false;
+}
+
+/*
+ * Execute the scan. Called "simultaneously" on all threads of a core
+ * at high priority using the stop_cpus mechanism.
+ */
+static int doscan(void *data)
+{
+	int cpu = smp_processor_id();
+	u64 *msrs = data;
+	int first;
+
+	/* Only the first logical CPU on a core reports result */
+	first = cpumask_first(cpu_smt_mask(cpu));
+
+	/*
+	 * This WRMSR will wait for other HT threads to also write
+	 * to this MSR (at most for activate.delay cycles). Then it
+	 * starts scan of each requested chunk. The core scan happens
+	 * during the "execution" of the WRMSR. This instruction can
+	 * take up to 200 milliseconds (in the case where all chunks
+	 * are processed in a single pass) before it retires.
+	 */
+	wrmsrl(MSR_ACTIVATE_SCAN, msrs[0]);
+
+	if (cpu == first) {
+		/* Pass back the result of the scan */
+		rdmsrl(MSR_SCAN_STATUS, msrs[1]);
+	}
+
+	return 0;
+}
+
+/*
+ * Use stop_core_cpuslocked() to synchronize writing to MSR_ACTIVATE_SCAN
+ * on all threads of the core to be tested. Loop if necessary to complete
+ * run of all chunks. Include some defensive tests to make sure forward
+ * progress is made, and that the whole test completes in a reasonable time.
+ */
+static void ifs_test_core(int cpu, struct device *dev)
+{
+	union ifs_scan activate;
+	union ifs_status status;
+	unsigned long timeout;
+	struct ifs_data *ifsd;
+	u64 msrvals[2];
+	int retries;
+
+	ifsd = ifs_get_data(dev);
+
+	activate.rsvd = 0;
+	activate.delay = IFS_THREAD_WAIT;
+	activate.sigmce = 0;
+	activate.start = 0;
+	activate.stop = ifsd->valid_chunks - 1;
+
+	timeout = jiffies + HZ / 2;
+	retries = MAX_IFS_RETRIES;
+
+	while (activate.start <= activate.stop) {
+		if (time_after(jiffies, timeout)) {
+			status.error_code = IFS_SW_TIMEOUT;
+			break;
+		}
+
+		msrvals[0] = activate.data;
+		stop_core_cpuslocked(cpu, doscan, msrvals);
+
+		status.data = msrvals[1];
+
+		trace_ifs_status(cpu, activate, status);
+
+		/* Some cases can be retried, give up for others */
+		if (!can_restart(status))
+			break;
+
+		if (status.chunk_num == activate.start) {
+			/* Check for forward progress */
+			if (--retries == 0) {
+				if (status.error_code == IFS_NO_ERROR)
+					status.error_code = IFS_SW_PARTIAL_COMPLETION;
+				break;
+			}
+		} else {
+			retries = MAX_IFS_RETRIES;
+			activate.start = status.chunk_num;
+		}
+	}
+
+	/* Update status for this core */
+	ifsd->scan_details = status.data;
+
+	if (status.control_error || status.signature_error) {
+		ifsd->status = SCAN_TEST_FAIL;
+		message_fail(dev, cpu, status);
+	} else if (status.error_code) {
+		ifsd->status = SCAN_NOT_TESTED;
+		message_not_tested(dev, cpu, status);
+	} 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
+ * wait for all sibling threads to finish the scan test.
+ */
+int do_core_test(int cpu, struct device *dev)
+{
+	int ret = 0;
+
+	/* Prevent CPUs from being taken offline during the scan test */
+	cpus_read_lock();
+
+	if (!cpu_online(cpu)) {
+		dev_info(dev, "cannot test on the offline cpu %d\n", cpu);
+		ret = -EINVAL;
+		goto out;
+	}
+
+	ifs_test_core(cpu, dev);
+out:
+	cpus_read_unlock();
+	return ret;
+}