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