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