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 26 static int __initdata nmi_fail; 27 28 /* check to see if NMI IPIs work on this machine */ 29 static DECLARE_BITMAP(nmi_ipi_mask, NR_CPUS) __initdata; 30 31 static int __initdata testcase_total; 32 static int __initdata testcase_successes; 33 static int __initdata expected_testcase_failures; 34 static int __initdata unexpected_testcase_failures; 35 static int __initdata unexpected_testcase_unknowns; 36 37 static int __init nmi_unk_cb(unsigned int val, struct pt_regs *regs) 38 { 39 unexpected_testcase_unknowns++; 40 return NMI_HANDLED; 41 } 42 43 static 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 50 static void __init cleanup_nmi_testsuite(void) 51 { 52 unregister_nmi_handler(NMI_UNKNOWN, "nmi_selftest_unk"); 53 } 54 55 static 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 65 static 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 93 static 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 } 100 101 static 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 } 107 108 static void __init reset_nmi(void) 109 { 110 nmi_fail = 0; 111 } 112 113 static 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 } 137 138 static inline void __init print_testname(const char *testname) 139 { 140 printk("%12s:", testname); 141 } 142 143 void __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