kernel/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 #include <linux/percpu.h>
  17
  18 #include <asm/apic.h>
  19 #include <asm/nmi.h>
  20
  21 #define SUCCESS         0
  22 #define FAILURE         1
  23 #define TIMEOUT         2
  24
  25 static int __initdata nmi_fail;
  26
  27 /* check to see if NMI IPIs work on this machine */
  28 static DECLARE_BITMAP(nmi_ipi_mask, NR_CPUS) __initdata;
  29
  30 static int __initdata testcase_total;
  31 static int __initdata testcase_successes;
  32 static int __initdata expected_testcase_failures;
  33 static int __initdata unexpected_testcase_failures;
  34 static int __initdata unexpected_testcase_unknowns;
  35
  36 static int __init nmi_unk_cb(unsigned int val, struct pt_regs *regs)
  37 {
  38         unexpected_testcase_unknowns++;
  39         return NMI_HANDLED;
  40 }
  41
  42 static void __init init_nmi_testsuite(void)
  43 {
  44         /* trap all the unknown NMIs we may generate */
  45         register_nmi_handler(NMI_UNKNOWN, nmi_unk_cb, 0, "nmi_selftest_unk",
  46                         __initdata);
  47 }
  48
  49 static void __init cleanup_nmi_testsuite(void)
  50 {
  51         unregister_nmi_handler(NMI_UNKNOWN, "nmi_selftest_unk");
  52 }
  53
  54 static int __init test_nmi_ipi_callback(unsigned int val, struct pt_regs *regs)
  55 {
  56         int cpu = raw_smp_processor_id();
  57
  58         if (cpumask_test_and_clear_cpu(cpu, to_cpumask(nmi_ipi_mask)))
  59                 return NMI_HANDLED;
  60
  61         return NMI_DONE;
  62 }
  63
  64 static void __init test_nmi_ipi(struct cpumask *mask)
  65 {
  66         unsigned long timeout;
  67
  68         if (register_nmi_handler(NMI_LOCAL, test_nmi_ipi_callback,
  69                                  NMI_FLAG_FIRST, "nmi_selftest", __initdata)) {
  70                 nmi_fail = FAILURE;
  71                 return;
  72         }
  73
  74         /* sync above data before sending NMI */
  75         wmb();
  76
  77         apic->send_IPI_mask(mask, NMI_VECTOR);
  78
  79         /* Don't wait longer than a second */
  80         timeout = USEC_PER_SEC;
  81         while (!cpumask_empty(mask) && timeout--)
  82                 udelay(1);
  83
  84         /* What happens if we timeout, do we still unregister?? */
  85         unregister_nmi_handler(NMI_LOCAL, "nmi_selftest");
  86
  87         if (!timeout)
  88                 nmi_fail = TIMEOUT;
  89         return;
  90 }
  91
  92 static void __init remote_ipi(void)
  93 {
  94         cpumask_copy(to_cpumask(nmi_ipi_mask), cpu_online_mask);
  95         cpumask_clear_cpu(smp_processor_id(), to_cpumask(nmi_ipi_mask));
  96         if (!cpumask_empty(to_cpumask(nmi_ipi_mask)))
  97                 test_nmi_ipi(to_cpumask(nmi_ipi_mask));
  98 }
  99
 100 static void __init local_ipi(void)
 101 {
 102         cpumask_clear(to_cpumask(nmi_ipi_mask));
 103         cpumask_set_cpu(smp_processor_id(), to_cpumask(nmi_ipi_mask));
 104         test_nmi_ipi(to_cpumask(nmi_ipi_mask));
 105 }
 106
 107 static void __init reset_nmi(void)
 108 {
 109         nmi_fail = 0;
 110 }
 111
 112 static void __init dotest(void (*testcase_fn)(void), int expected)
 113 {
 114         testcase_fn();
 115         /*
 116          * Filter out expected failures:
 117          */
 118         if (nmi_fail != expected) {
 119                 unexpected_testcase_failures++;
 120
 121                 if (nmi_fail == FAILURE)
 122                         printk(KERN_CONT "FAILED |");
 123                 else if (nmi_fail == TIMEOUT)
 124                         printk(KERN_CONT "TIMEOUT|");
 125                 else
 126                         printk(KERN_CONT "ERROR  |");
 127                 dump_stack();
 128         } else {
 129                 testcase_successes++;
 130                 printk(KERN_CONT "  ok  |");
 131         }
 132         testcase_total++;
 133
 134         reset_nmi();
 135 }
 136
 137 static inline void __init print_testname(const char *testname)
 138 {
 139         printk("%12s:", testname);
 140 }
 141
 142 void __init nmi_selftest(void)
 143 {
 144         init_nmi_testsuite();
 145
 146         /*
 147          * Run the testsuite:
 148          */
 149         printk("----------------\n");
 150         printk("| NMI testsuite:\n");
 151         printk("--------------------\n");
 152
 153         print_testname("remote IPI");
 154         dotest(remote_ipi, SUCCESS);
 155         printk(KERN_CONT "\n");
 156         print_testname("local IPI");
 157         dotest(local_ipi, SUCCESS);
 158         printk(KERN_CONT "\n");
 159
 160         cleanup_nmi_testsuite();
 161
 162         if (unexpected_testcase_failures) {
 163                 printk("--------------------\n");
 164                 printk("BUG: %3d unexpected failures (out of %3d) - debugging disabled! |\n",
 165                         unexpected_testcase_failures, testcase_total);
 166                 printk("-----------------------------------------------------------------\n");
 167         } else if (expected_testcase_failures && testcase_successes) {
 168                 printk("--------------------\n");
 169                 printk("%3d out of %3d testcases failed, as expected. |\n",
 170                         expected_testcase_failures, testcase_total);
 171                 printk("----------------------------------------------------\n");
 172         } else if (expected_testcase_failures && !testcase_successes) {
 173                 printk("--------------------\n");
 174                 printk("All %3d testcases failed, as expected. |\n",
 175                         expected_testcase_failures);
 176                 printk("----------------------------------------\n");
 177         } else {
 178                 printk("--------------------\n");
 179                 printk("Good, all %3d testcases passed! |\n",
 180                         testcase_successes);
 181                 printk("---------------------------------\n");
 182         }
 183 }