LXR linux/arch/x86/kernel/nmi

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * arch/x86/kernel/nmi-selftest.c
   4 *
   5 * Testsuite for NMI: IPIs
   6 *
   7 * Started by Don Zickus:
   8 * (using lib/locking-selftest.c as a guide)
   9 *
  10 *   Copyright (C) 2011 Red Hat, Inc., Don Zickus <dzickus@redhat.com>
  11 */
  12
  13#include <linux/smp.h>
  14#include <linux/cpumask.h>
  15#include <linux/delay.h>
  16#include <linux/init.h>
  17#include <linux/percpu.h>
  18
  19#include <asm/apic.h>
  20#include <asm/nmi.h>
  21
  22#define SUCCESS         0
  23#define FAILURE         1
  24#define TIMEOUT         2
  25
  26static int __initdata nmi_fail;
  27
  28/* check to see if NMI IPIs work on this machine */
  29static DECLARE_BITMAP(nmi_ipi_mask, NR_CPUS) __initdata;
  30
  31static int __initdata testcase_total;
  32static int __initdata testcase_successes;
  33static int __initdata expected_testcase_failures;
  34static int __initdata unexpected_testcase_failures;
  35static int __initdata unexpected_testcase_unknowns;
  36
  37static int __init nmi_unk_cb(unsigned int val, struct pt_regs *regs)
  38{
  39        unexpected_testcase_unknowns++;
  40        return NMI_HANDLED;
  41}
  42
  43static void __init init_nmi_testsuite(void)
  44{
  45        /* trap all the unknown NMIs we may generate */
  46        register_nmi_handler(NMI_UNKNOWN, nmi_unk_cb, 0, "nmi_selftest_unk",
  47                        __initdata);
  48}
  49
  50static void __init cleanup_nmi_testsuite(void)
  51{
  52        unregister_nmi_handler(NMI_UNKNOWN, "nmi_selftest_unk");
  53}
  54
  55static int __init test_nmi_ipi_callback(unsigned int val, struct pt_regs *regs)
  56{
  57        int cpu = raw_smp_processor_id();
  58
  59        if (cpumask_test_and_clear_cpu(cpu, to_cpumask(nmi_ipi_mask)))
  60                return NMI_HANDLED;
  61
  62        return NMI_DONE;
  63}
  64
  65static void __init test_nmi_ipi(struct cpumask *mask)
  66{
  67        unsigned long timeout;
  68
  69        if (register_nmi_handler(NMI_LOCAL, test_nmi_ipi_callback,
  70                                 NMI_FLAG_FIRST, "nmi_selftest", __initdata)) {
  71                nmi_fail = FAILURE;
  72                return;
  73        }
  74
  75        /* sync above data before sending NMI */
  76        wmb();
  77
  78        apic->send_IPI_mask(mask, NMI_VECTOR);
  79
  80        /* Don't wait longer than a second */
  81        timeout = USEC_PER_SEC;
  82        while (!cpumask_empty(mask) && --timeout)
  83                udelay(1);
  84
  85        /* What happens if we timeout, do we still unregister?? */
  86        unregister_nmi_handler(NMI_LOCAL, "nmi_selftest");
  87
  88        if (!timeout)
  89                nmi_fail = TIMEOUT;
  90        return;
  91}
  92
  93static void __init remote_ipi(void)
  94{
  95        cpumask_copy(to_cpumask(nmi_ipi_mask), cpu_online_mask);
  96        cpumask_clear_cpu(smp_processor_id(), to_cpumask(nmi_ipi_mask));
  97        if (!cpumask_empty(to_cpumask(nmi_ipi_mask)))
  98                test_nmi_ipi(to_cpumask(nmi_ipi_mask));
  99}
 100
 101static void __init local_ipi(void)
 102{
 103        cpumask_clear(to_cpumask(nmi_ipi_mask));
 104        cpumask_set_cpu(smp_processor_id(), to_cpumask(nmi_ipi_mask));
 105        test_nmi_ipi(to_cpumask(nmi_ipi_mask));
 106}
 107
 108static void __init reset_nmi(void)
 109{
 110        nmi_fail = 0;
 111}
 112
 113static void __init dotest(void (*testcase_fn)(void), int expected)
 114{
 115        testcase_fn();
 116        /*
 117         * Filter out expected failures:
 118         */
 119        if (nmi_fail != expected) {
 120                unexpected_testcase_failures++;
 121
 122                if (nmi_fail == FAILURE)
 123                        printk(KERN_CONT "FAILED |");
 124                else if (nmi_fail == TIMEOUT)
 125                        printk(KERN_CONT "TIMEOUT|");
 126                else
 127                        printk(KERN_CONT "ERROR  |");
 128                dump_stack();
 129        } else {
 130                testcase_successes++;
 131                printk(KERN_CONT "  ok  |");
 132        }
 133        testcase_total++;
 134
 135        reset_nmi();
 136}
 137
 138static inline void __init print_testname(const char *testname)
 139{
 140        printk("%12s:", testname);
 141}
 142
 143void __init nmi_selftest(void)
 144{
 145        init_nmi_testsuite();
 146
 147        /*
 148         * Run the testsuite:
 149         */
 150        printk("----------------\n");
 151        printk("| NMI testsuite:\n");
 152        printk("--------------------\n");
 153
 154        print_testname("remote IPI");
 155        dotest(remote_ipi, SUCCESS);
 156        printk(KERN_CONT "\n");
 157        print_testname("local IPI");
 158        dotest(local_ipi, SUCCESS);
 159        printk(KERN_CONT "\n");
 160
 161        cleanup_nmi_testsuite();
 162
 163        if (unexpected_testcase_failures) {
 164                printk("--------------------\n");
 165                printk("BUG: %3d unexpected failures (out of %3d) - debugging disabled! |\n",
 166                        unexpected_testcase_failures, testcase_total);
 167                printk("-----------------------------------------------------------------\n");
 168        } else if (expected_testcase_failures && testcase_successes) {
 169                printk("--------------------\n");
 170                printk("%3d out of %3d testcases failed, as expected. |\n",
 171                        expected_testcase_failures, testcase_total);
 172                printk("----------------------------------------------------\n");
 173        } else if (expected_testcase_failures && !testcase_successes) {
 174                printk("--------------------\n");
 175                printk("All %3d testcases failed, as expected. |\n",
 176                        expected_testcase_failures);
 177                printk("----------------------------------------\n");
 178        } else {
 179                printk("--------------------\n");
 180                printk("Good, all %3d testcases passed! |\n",
 181                        testcase_successes);
 182                printk("---------------------------------\n");
 183        }
 184}
 185