Pileus Git - ~andy/linux/blob - arch/x86/kernel/nmi_selftest.c

   1 /*
   2  * arch/x86/kernel/nmi-selftest.c
   3  *
   4  * Testsuite for NMI: IPIs
   5  *
   6  * Started by Don Zickus:
   7  * (using lib/locking-selftest.c as a guide)
   8  *
   9  *   Copyright (C) 2011 Red Hat, Inc., Don Zickus <dzickus@redhat.com>
  10  */
  11
  12 #include <linux/smp.h>
  13 #include <linux/cpumask.h>
  14 #include <linux/delay.h>
  15 #include <linux/init.h>
  16
  17 #include <asm/apic.h>
  18 #include <asm/nmi.h>
  19
  20 #define SUCCESS         0
  21 #define FAILURE         1
  22 #define TIMEOUT         2
  23
  24 static int __initdata nmi_fail;
  25
  26 /* check to see if NMI IPIs work on this machine */
  27 static DECLARE_BITMAP(nmi_ipi_mask, NR_CPUS) __initdata;
  28
  29 static int __initdata testcase_total;
  30 static int __initdata testcase_successes;
  31 static int __initdata expected_testcase_failures;
  32 static int __initdata unexpected_testcase_failures;
  33 static int __initdata unexpected_testcase_unknowns;
  34
  35 static int __init nmi_unk_cb(unsigned int val, struct pt_regs *regs)
  36 {
  37         unexpected_testcase_unknowns++;
  38         return NMI_HANDLED;
  39 }
  40
  41 static void __init init_nmi_testsuite(void)
  42 {
  43         /* trap all the unknown NMIs we may generate */
  44         register_nmi_handler(NMI_UNKNOWN, nmi_unk_cb, 0, "nmi_selftest_unk");
  45 }
  46
  47 static void __init cleanup_nmi_testsuite(void)
  48 {
  49         unregister_nmi_handler(NMI_UNKNOWN, "nmi_selftest_unk");
  50 }
  51
  52 static int __init test_nmi_ipi_callback(unsigned int val, struct pt_regs *regs)
  53 {
  54         int cpu = raw_smp_processor_id();
  55
  56         if (cpumask_test_and_clear_cpu(cpu, to_cpumask(nmi_ipi_mask)))
  57                 return NMI_HANDLED;
  58
  59         return NMI_DONE;
  60 }
  61
  62 static void __init test_nmi_ipi(struct cpumask *mask)
  63 {
  64         unsigned long timeout;
  65
  66         if (register_nmi_handler(NMI_LOCAL, test_nmi_ipi_callback,
  67                                  NMI_FLAG_FIRST, "nmi_selftest")) {
  68                 nmi_fail = FAILURE;
  69                 return;
  70         }
  71
  72         /* sync above data before sending NMI */
  73         wmb();
  74
  75         apic->send_IPI_mask(mask, NMI_VECTOR);
  76
  77         /* Don't wait longer than a second */
  78         timeout = USEC_PER_SEC;
  79         while (!cpumask_empty(mask) && timeout--)
  80                 udelay(1);
  81
  82         /* What happens if we timeout, do we still unregister?? */
  83         unregister_nmi_handler(NMI_LOCAL, "nmi_selftest");
  84
  85         if (!timeout)
  86                 nmi_fail = TIMEOUT;
  87         return;
  88 }
  89
  90 static void __init remote_ipi(void)
  91 {
  92         cpumask_copy(to_cpumask(nmi_ipi_mask), cpu_online_mask);
  93         cpumask_clear_cpu(smp_processor_id(), to_cpumask(nmi_ipi_mask));
  94         if (!cpumask_empty(to_cpumask(nmi_ipi_mask)))
  95                 test_nmi_ipi(to_cpumask(nmi_ipi_mask));
  96 }
  97
  98 static void __init local_ipi(void)
  99 {
 100         cpumask_clear(to_cpumask(nmi_ipi_mask));
 101         cpumask_set_cpu(smp_processor_id(), to_cpumask(nmi_ipi_mask));
 102         test_nmi_ipi(to_cpumask(nmi_ipi_mask));
 103 }
 104
 105 static void __init reset_nmi(void)
 106 {
 107         nmi_fail = 0;
 108 }
 109
 110 static void __init dotest(void (*testcase_fn)(void), int expected)
 111 {
 112         testcase_fn();
 113         /*
 114          * Filter out expected failures:
 115          */
 116         if (nmi_fail != expected) {
 117                 unexpected_testcase_failures++;
 118
 119                 if (nmi_fail == FAILURE)
 120                         printk("FAILED |");
 121                 else if (nmi_fail == TIMEOUT)
 122                         printk("TIMEOUT|");
 123                 else
 124                         printk("ERROR  |");
 125                 dump_stack();
 126         } else {
 127                 testcase_successes++;
 128                 printk("  ok  |");
 129         }
 130         testcase_total++;
 131
 132         reset_nmi();
 133 }
 134
 135 static inline void __init print_testname(const char *testname)
 136 {
 137         printk("%12s:", testname);
 138 }
 139
 140 void __init nmi_selftest(void)
 141 {
 142         init_nmi_testsuite();
 143
 144         /*
 145          * Run the testsuite:
 146          */
 147         printk("----------------\n");
 148         printk("| NMI testsuite:\n");
 149         printk("--------------------\n");
 150
 151         print_testname("remote IPI");
 152         dotest(remote_ipi, SUCCESS);
 153         printk("\n");
 154         print_testname("local IPI");
 155         dotest(local_ipi, SUCCESS);
 156         printk("\n");
 157
 158         cleanup_nmi_testsuite();
 159
 160         if (unexpected_testcase_failures) {
 161                 printk("--------------------\n");
 162                 printk("BUG: %3d unexpected failures (out of %3d) - debugging disabled! |\n",
 163                         unexpected_testcase_failures, testcase_total);
 164                 printk("-----------------------------------------------------------------\n");
 165         } else if (expected_testcase_failures && testcase_successes) {
 166                 printk("--------------------\n");
 167                 printk("%3d out of %3d testcases failed, as expected. |\n",
 168                         expected_testcase_failures, testcase_total);
 169                 printk("----------------------------------------------------\n");
 170         } else if (expected_testcase_failures && !testcase_successes) {
 171                 printk("--------------------\n");
 172                 printk("All %3d testcases failed, as expected. |\n",
 173                         expected_testcase_failures);
 174                 printk("----------------------------------------\n");
 175         } else {
 176                 printk("--------------------\n");
 177                 printk("Good, all %3d testcases passed! |\n",
 178                         testcase_successes);
 179                 printk("---------------------------------\n");
 180         }
 181 }