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authorDon Zickus <dzickus@redhat.com>2011-10-13 23:14:26 +0400
committerIngo Molnar <mingo@elte.hu>2011-12-05 15:00:16 +0400
commit99e8b9ca90d688c3ac7d3a141b701c9694a93925 (patch)
tree1893fd5fce8c3d8ae52440d9db7d23be7fdecbc9 /arch/x86/kernel/nmi_selftest.c
parent3603a2512f9e69dc87914ba922eb4a0812b21cd6 (diff)
downloadlinux-99e8b9ca90d688c3ac7d3a141b701c9694a93925.tar.xz
x86, NMI: Add NMI IPI selftest
The previous patch modified the stop cpus path to use NMI instead of IRQ as the way to communicate to the other cpus to shutdown. There were some concerns that various machines may have problems with using an NMI IPI. This patch creates a selftest to check if NMI is working at boot. The idea is to help catch any issues before the machine panics and we learn the hard way. Loosely based on the locking-selftest.c file, this separate file runs a couple of simple tests and reports the results. The output looks like: ... Brought up 4 CPUs ---------------- | NMI testsuite: -------------------- remote IPI: ok | local IPI: ok | -------------------- Good, all 2 testcases passed! | --------------------------------- Total of 4 processors activated (21330.61 BogoMIPS). ... Signed-off-by: Don Zickus <dzickus@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Robert Richter <robert.richter@amd.com> Cc: seiji.aguchi@hds.com Cc: vgoyal@redhat.com Cc: mjg@redhat.com Cc: tony.luck@intel.com Cc: gong.chen@intel.com Cc: satoru.moriya@hds.com Cc: avi@redhat.com Cc: Andi Kleen <andi@firstfloor.org> Link: http://lkml.kernel.org/r/1318533267-18880-3-git-send-email-dzickus@redhat.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/kernel/nmi_selftest.c')
-rw-r--r--arch/x86/kernel/nmi_selftest.c179
1 files changed, 179 insertions, 0 deletions
diff --git a/arch/x86/kernel/nmi_selftest.c b/arch/x86/kernel/nmi_selftest.c
new file mode 100644
index 000000000000..572adb622251
--- /dev/null
+++ b/arch/x86/kernel/nmi_selftest.c
@@ -0,0 +1,179 @@
+/*
+ * arch/x86/kernel/nmi-selftest.c
+ *
+ * Testsuite for NMI: IPIs
+ *
+ * Started by Don Zickus:
+ * (using lib/locking-selftest.c as a guide)
+ *
+ * Copyright (C) 2011 Red Hat, Inc., Don Zickus <dzickus@redhat.com>
+ */
+
+#include <linux/smp.h>
+#include <linux/cpumask.h>
+#include <linux/delay.h>
+
+#include <asm/apic.h>
+#include <asm/nmi.h>
+
+#define SUCCESS 0
+#define FAILURE 1
+#define TIMEOUT 2
+
+static int nmi_fail;
+
+/* check to see if NMI IPIs work on this machine */
+static DECLARE_BITMAP(nmi_ipi_mask, NR_CPUS) __read_mostly;
+
+static int testcase_total;
+static int testcase_successes;
+static int expected_testcase_failures;
+static int unexpected_testcase_failures;
+static int unexpected_testcase_unknowns;
+
+static int nmi_unk_cb(unsigned int val, struct pt_regs *regs)
+{
+ unexpected_testcase_unknowns++;
+ return NMI_HANDLED;
+}
+
+static void init_nmi_testsuite(void)
+{
+ /* trap all the unknown NMIs we may generate */
+ register_nmi_handler(NMI_UNKNOWN, nmi_unk_cb, 0, "nmi_selftest_unk");
+}
+
+static void cleanup_nmi_testsuite(void)
+{
+ unregister_nmi_handler(NMI_UNKNOWN, "nmi_selftest_unk");
+}
+
+static int test_nmi_ipi_callback(unsigned int val, struct pt_regs *regs)
+{
+ int cpu = raw_smp_processor_id();
+
+ if (cpumask_test_and_clear_cpu(cpu, to_cpumask(nmi_ipi_mask)))
+ return NMI_HANDLED;
+
+ return NMI_DONE;
+}
+
+static void test_nmi_ipi(struct cpumask *mask)
+{
+ unsigned long timeout;
+
+ if (register_nmi_handler(NMI_LOCAL, test_nmi_ipi_callback,
+ NMI_FLAG_FIRST, "nmi_selftest")) {
+ nmi_fail = FAILURE;
+ return;
+ }
+
+ /* sync above data before sending NMI */
+ wmb();
+
+ apic->send_IPI_mask(mask, NMI_VECTOR);
+
+ /* Don't wait longer than a second */
+ timeout = USEC_PER_SEC;
+ while (!cpumask_empty(mask) && timeout--)
+ udelay(1);
+
+ /* What happens if we timeout, do we still unregister?? */
+ unregister_nmi_handler(NMI_LOCAL, "nmi_selftest");
+
+ if (!timeout)
+ nmi_fail = TIMEOUT;
+ return;
+}
+
+static void remote_ipi(void)
+{
+ cpumask_copy(to_cpumask(nmi_ipi_mask), cpu_online_mask);
+ cpumask_clear_cpu(smp_processor_id(), to_cpumask(nmi_ipi_mask));
+ test_nmi_ipi(to_cpumask(nmi_ipi_mask));
+}
+
+static void local_ipi(void)
+{
+ cpumask_clear(to_cpumask(nmi_ipi_mask));
+ cpumask_set_cpu(smp_processor_id(), to_cpumask(nmi_ipi_mask));
+ test_nmi_ipi(to_cpumask(nmi_ipi_mask));
+}
+
+static void reset_nmi(void)
+{
+ nmi_fail = 0;
+}
+
+static void dotest(void (*testcase_fn)(void), int expected)
+{
+ testcase_fn();
+ /*
+ * Filter out expected failures:
+ */
+ if (nmi_fail != expected) {
+ unexpected_testcase_failures++;
+
+ if (nmi_fail == FAILURE)
+ printk("FAILED |");
+ else if (nmi_fail == TIMEOUT)
+ printk("TIMEOUT|");
+ else
+ printk("ERROR |");
+ dump_stack();
+ } else {
+ testcase_successes++;
+ printk(" ok |");
+ }
+ testcase_total++;
+
+ reset_nmi();
+}
+
+static inline void print_testname(const char *testname)
+{
+ printk("%12s:", testname);
+}
+
+void nmi_selftest(void)
+{
+ init_nmi_testsuite();
+
+ /*
+ * Run the testsuite:
+ */
+ printk("----------------\n");
+ printk("| NMI testsuite:\n");
+ printk("--------------------\n");
+
+ print_testname("remote IPI");
+ dotest(remote_ipi, SUCCESS);
+ printk("\n");
+ print_testname("local IPI");
+ dotest(local_ipi, SUCCESS);
+ printk("\n");
+
+ cleanup_nmi_testsuite();
+
+ if (unexpected_testcase_failures) {
+ printk("--------------------\n");
+ printk("BUG: %3d unexpected failures (out of %3d) - debugging disabled! |\n",
+ unexpected_testcase_failures, testcase_total);
+ printk("-----------------------------------------------------------------\n");
+ } else if (expected_testcase_failures && testcase_successes) {
+ printk("--------------------\n");
+ printk("%3d out of %3d testcases failed, as expected. |\n",
+ expected_testcase_failures, testcase_total);
+ printk("----------------------------------------------------\n");
+ } else if (expected_testcase_failures && !testcase_successes) {
+ printk("--------------------\n");
+ printk("All %3d testcases failed, as expected. |\n",
+ expected_testcase_failures);
+ printk("----------------------------------------\n");
+ } else {
+ printk("--------------------\n");
+ printk("Good, all %3d testcases passed! |\n",
+ testcase_successes);
+ printk("---------------------------------\n");
+ }
+}