// SPDX-License-Identifier: GPL-2.0
/*
 * Testsuite for NMI: IPIs
 *
 * Started by Don Zickus:
 * (using lib/locking-selftest.c as a guide)
 *
 *   Copyright (C) 2011 Red Hat, Inc., Don Zickus <dzickus@redhat.com>
 */

#include <linux/smp.h>
#include <linux/cpumask.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/percpu.h>

#include <asm/apic.h>
#include <asm/nmi.h>

#define SUCCESS         0
#define FAILURE         1
#define TIMEOUT         2

static int __initdata nmi_fail;

/* check to see if NMI IPIs work on this machine */
static DECLARE_BITMAP(nmi_ipi_mask, NR_CPUS) __initdata;

static int __initdata testcase_total;
static int __initdata testcase_successes;
static int __initdata unexpected_testcase_failures;
static int __initdata unexpected_testcase_unknowns;

static int __init nmi_unk_cb(unsigned int val, struct pt_regs *regs)
{
        unexpected_testcase_unknowns++;
        return NMI_HANDLED;
}

static void __init init_nmi_testsuite(void)
{
        /* trap all the unknown NMIs we may generate */
        register_nmi_handler(NMI_UNKNOWN, nmi_unk_cb, 0, "nmi_selftest_unk",
                        __initdata);
}

static void __init cleanup_nmi_testsuite(void)
{
        unregister_nmi_handler(NMI_UNKNOWN, "nmi_selftest_unk");
}

static int __init test_nmi_ipi_callback(unsigned int val, struct pt_regs *regs)
{
        int cpu = raw_smp_processor_id();

        if (cpumask_test_and_clear_cpu(cpu, to_cpumask(nmi_ipi_mask)))
                return NMI_HANDLED;

        return NMI_DONE;
}

static void __init test_nmi_ipi(struct cpumask *mask)
{
        unsigned long timeout;

        if (register_nmi_handler(NMI_LOCAL, test_nmi_ipi_callback,
                                 NMI_FLAG_FIRST, "nmi_selftest", __initdata)) {
                nmi_fail = FAILURE;
                return;
        }

        /* sync above data before sending NMI */
        wmb();

        __apic_send_IPI_mask(mask, NMI_VECTOR);

        /* Don't wait longer than a second */
        timeout = USEC_PER_SEC;
        while (!cpumask_empty(mask) && --timeout)
                udelay(1);

        /* What happens if we timeout, do we still unregister?? */
        unregister_nmi_handler(NMI_LOCAL, "nmi_selftest");

        if (!timeout)
                nmi_fail = TIMEOUT;
        return;
}

static void __init remote_ipi(void)
{
        cpumask_copy(to_cpumask(nmi_ipi_mask), cpu_online_mask);
        cpumask_clear_cpu(smp_processor_id(), to_cpumask(nmi_ipi_mask));
        if (!cpumask_empty(to_cpumask(nmi_ipi_mask)))
                test_nmi_ipi(to_cpumask(nmi_ipi_mask));
}

static void __init local_ipi(void)
{
        cpumask_clear(to_cpumask(nmi_ipi_mask));
        cpumask_set_cpu(smp_processor_id(), to_cpumask(nmi_ipi_mask));
        test_nmi_ipi(to_cpumask(nmi_ipi_mask));
}

static void __init reset_nmi(void)
{
        nmi_fail = 0;
}

static void __init dotest(void (*testcase_fn)(void), int expected)
{
        testcase_fn();
        /*
         * Filter out expected failures:
         */
        if (nmi_fail != expected) {
                unexpected_testcase_failures++;

                if (nmi_fail == FAILURE)
                        pr_cont("FAILED |");
                else if (nmi_fail == TIMEOUT)
                        pr_cont("TIMEOUT|");
                else
                        pr_cont("ERROR  |");
                dump_stack();
        } else {
                testcase_successes++;
                pr_cont("  ok  |");
        }
        pr_cont("\n");

        testcase_total++;
        reset_nmi();
}

void __init nmi_selftest(void)
{
        init_nmi_testsuite();

        /*
         * Run the testsuite:
         */
        pr_info("----------------\n");
        pr_info("| NMI testsuite:\n");
        pr_info("--------------------\n");

        pr_info("%12s:", "remote IPI");
        dotest(remote_ipi, SUCCESS);

        pr_info("%12s:", "local IPI");
        dotest(local_ipi, SUCCESS);

        cleanup_nmi_testsuite();

        pr_info("--------------------\n");
        if (unexpected_testcase_failures) {
                pr_info("BUG: %3d unexpected failures (out of %3d) - debugging disabled! |\n",
                        unexpected_testcase_failures, testcase_total);
        } else {
                pr_info("Good, all %3d testcases passed! |\n",
                        testcase_successes);
        }
        pr_info("-----------------------------------------------------------------\n");
}