xref: /openbmc/linux/arch/x86/kernel/nmi_selftest.c (revision 2c684d89)
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 }
184