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
24 static int __initdata nmi_fail;
25
26 /* check to see if NMI IPIs work on this machine */
27 static DECLARE_BITMAP(nmi_ipi_mask, NR_CPUS) __initdata;
28
29 static int __initdata testcase_total;
30 static int __initdata testcase_successes;
31 static int __initdata expected_testcase_failures;
32 static int __initdata unexpected_testcase_failures;
33 static int __initdata unexpected_testcase_unknowns;
34
nmi_unk_cb(unsigned int val,struct pt_regs * regs)35 static int __init nmi_unk_cb(unsigned int val, struct pt_regs *regs)
36 {
37 unexpected_testcase_unknowns++;
38 return NMI_HANDLED;
39 }
40
init_nmi_testsuite(void)41 static 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
cleanup_nmi_testsuite(void)47 static void __init cleanup_nmi_testsuite(void)
48 {
49 unregister_nmi_handler(NMI_UNKNOWN, "nmi_selftest_unk");
50 }
51
test_nmi_ipi_callback(unsigned int val,struct pt_regs * regs)52 static 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
test_nmi_ipi(struct cpumask * mask)62 static 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
remote_ipi(void)90 static 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
local_ipi(void)98 static 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
reset_nmi(void)105 static void __init reset_nmi(void)
106 {
107 nmi_fail = 0;
108 }
109
dotest(void (* testcase_fn)(void),int expected)110 static 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
print_testname(const char * testname)135 static inline void __init print_testname(const char *testname)
136 {
137 printk("%12s:", testname);
138 }
139
nmi_selftest(void)140 void __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