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