xref: /openbmc/linux/arch/x86/kernel/nmi_selftest.c (revision 28b82352)
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