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
nmi_unk_cb(unsigned int val,struct pt_regs * regs)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
init_nmi_testsuite(void)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
cleanup_nmi_testsuite(void)50 static void __init cleanup_nmi_testsuite(void)
51 {
52 unregister_nmi_handler(NMI_UNKNOWN, "nmi_selftest_unk");
53 }
54
test_nmi_ipi_callback(unsigned int val,struct pt_regs * regs)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
test_nmi_ipi(struct cpumask * mask)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
remote_ipi(void)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
local_ipi(void)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
reset_nmi(void)108 static void __init reset_nmi(void)
109 {
110 nmi_fail = 0;
111 }
112
dotest(void (* testcase_fn)(void),int expected)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
print_testname(const char * testname)138 static inline void __init print_testname(const char *testname)
139 {
140 printk("%12s:", testname);
141 }
142
nmi_selftest(void)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