/*-
 * Copyright (c) 2009 Advanced Computing Technologies LLC
 * Written by: John H. Baldwin <jhb@FreeBSD.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * Support for x86 machine check architecture.
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");

#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/sched.h>
#include <sys/smp.h>
#include <sys/sysctl.h>
#include <sys/systm.h>
#include <sys/taskqueue.h>
#include <machine/mca.h>
#include <machine/md_var.h>
#include <machine/specialreg.h>

struct mca_internal {
	struct mca_record rec;
	int		logged;
	STAILQ_ENTRY(mca_internal) link;
};

static MALLOC_DEFINE(M_MCA, "MCA", "Machine Check Architecture");

static int mca_count;		/* Number of records stored. */

SYSCTL_NODE(_hw, OID_AUTO, mca, CTLFLAG_RD, NULL, "Machine Check Architecture");

static int mca_enabled = 0;
TUNABLE_INT("hw.mca.enabled", &mca_enabled);
SYSCTL_INT(_hw_mca, OID_AUTO, enabled, CTLFLAG_RDTUN, &mca_enabled, 0,
    "Administrative toggle for machine check support");

static STAILQ_HEAD(, mca_internal) mca_records;
static struct callout mca_timer;
static int mca_ticks = 3600;	/* Check hourly by default. */
static struct task mca_task;
static struct mtx mca_lock;

static int
sysctl_mca_ticks(SYSCTL_HANDLER_ARGS)
{
	int error, value;

	value = mca_ticks;
	error = sysctl_handle_int(oidp, &value, 0, req);
	if (error || req->newptr == NULL)
		return (error);
	if (value <= 0)
		return (EINVAL);
	mca_ticks = value;
	return (0);
}

static int
sysctl_mca_records(SYSCTL_HANDLER_ARGS)
{
	int *name = (int *)arg1;
	u_int namelen = arg2;
	struct mca_record record;
	struct mca_internal *rec;
	int i;

	if (namelen != 1)
		return (EINVAL);

	if (name[0] < 0 || name[0] >= mca_count)
		return (EINVAL);

	mtx_lock_spin(&mca_lock);
	if (name[0] >= mca_count) {
		mtx_unlock_spin(&mca_lock);
		return (EINVAL);
	}
	i = 0;
	STAILQ_FOREACH(rec, &mca_records, link) {
		if (i == name[0]) {
			record = rec->rec;
			break;
		}
		i++;
	}
	mtx_unlock_spin(&mca_lock);
	return (SYSCTL_OUT(req, &record, sizeof(record)));
}

static struct mca_record *
mca_record_entry(int bank)
{
	struct mca_internal *rec;
	uint64_t status;
	u_int p[4];

	status = rdmsr(MSR_MC_STATUS(bank));
	if (!(status & MC_STATUS_VAL))
		return (NULL);

	rec = malloc(sizeof(*rec), M_MCA, M_NOWAIT | M_ZERO);
	if (rec == NULL) {
		printf("MCA: Unable to allocate space for an event.\n");
		return (NULL);
	}

	/* Save exception information. */
	rec->rec.mr_status = status;
	if (status & MC_STATUS_ADDRV)
		rec->rec.mr_addr = rdmsr(MSR_MC_ADDR(bank));
	if (status & MC_STATUS_MISCV)
		rec->rec.mr_misc = rdmsr(MSR_MC_MISC(bank));
	rec->rec.mr_tsc = rdtsc();
	rec->rec.mr_apic_id = PCPU_GET(apic_id);

	/*
	 * Clear machine check.  Don't do this for uncorrectable
	 * errors so that the BIOS can see them.
	 */
	if (!(rec->rec.mr_status & (MC_STATUS_PCC | MC_STATUS_UC))) {
		wrmsr(MSR_MC_STATUS(bank), 0);
		do_cpuid(0, p);
	}

	mtx_lock_spin(&mca_lock);
	STAILQ_INSERT_TAIL(&mca_records, rec, link);
	mca_count++;
	mtx_unlock_spin(&mca_lock);
	return (&rec->rec);
}

static const char *
mca_error_ttype(uint16_t mca_error)
{

	switch ((mca_error & 0x000c) >> 2) {
	case 0:
		return ("I");
	case 1:
		return ("D");
	case 2:
		return ("G");
	}
	return ("?");
}

static const char *
mca_error_level(uint16_t mca_error)
{

	switch (mca_error & 0x0003) {
	case 0:
		return ("L0");
	case 1:
		return ("L1");
	case 2:
		return ("L2");
	case 3:
		return ("LG");
	}
	return ("L?");
}

static const char *
mca_error_request(uint16_t mca_error)
{

	switch ((mca_error & 0x00f0) >> 4) {
	case 0x0:
		return ("ERR");
	case 0x1:
		return ("RD");
	case 0x2:
		return ("WR");
	case 0x3:
		return ("DRD");
	case 0x4:
		return ("DWR");
	case 0x5:
		return ("IRD");
	case 0x6:
		return ("PREFETCH");
	case 0x7:
		return ("EVICT");
	case 0x8:
		return ("SNOOP");
	}
	return ("???");
}

/* Dump details about a single machine check. */
static void
mca_log(struct mca_record *rec)
{
	uint16_t mca_error;

	printf("MCA: CPU %d ", rec->mr_apic_id);
	if (rec->mr_status & MC_STATUS_UC)
		printf("UNCOR ");
	else
		printf("COR ");
	if (rec->mr_status & MC_STATUS_PCC)
		printf("PCC ");
	if (rec->mr_status & MC_STATUS_OVER)
		printf("OVER ");
	mca_error = rec->mr_status & MC_STATUS_MCA_ERROR;
	switch (mca_error) {
		/* Simple error codes. */
	case 0x0000:
		printf("no error");
		break;
	case 0x0001:
		printf("unclassified error");
		break;
	case 0x0002:
		printf("ucode ROM parity error");
		break;
	case 0x0003:
		printf("external error");
		break;
	case 0x0004:
		printf("FRC error");
		break;
	case 0x0400:
		printf("internal timer error");
		break;
	default:
		if ((mca_error & 0xfc00) == 0x0400) {
			printf("internal error %x", mca_error & 0x03ff);
			break;
		}

		/* Compound error codes. */

		/* Memory hierarchy error. */
		if ((mca_error & 0xeffc) == 0x000c) {
			printf("%s memory error", mca_error_level(mca_error));
			break;
		}

		/* TLB error. */
		if ((mca_error & 0xeff0) == 0x0010) {
			printf("%sTLB %s error", mca_error_ttype(mca_error),
			    mca_error_level(mca_error));
			break;
		}

		/* Cache error. */
		if ((mca_error & 0xef00) == 0x0100) {
			printf("%sCACHE %s %s error",
			    mca_error_ttype(mca_error),
			    mca_error_level(mca_error),
			    mca_error_request(mca_error));
			break;
		}

		/* Bus and/or Interconnect error. */
		if ((mca_error & 0xe800) == 0x0800) {			
			printf("BUS%s ", mca_error_level(mca_error));
			switch ((mca_error & 0x0600) >> 9) {
			case 0:
				printf("Source");
				break;
			case 1:
				printf("Responder");
				break;
			case 2:
				printf("Observer");
				break;
			default:
				printf("???");
				break;
			}
			printf(" %s ", mca_error_request(mca_error));
			switch ((mca_error & 0x000c) >> 2) {
			case 0:
				printf("Memory");
				break;
			case 2:
				printf("I/O");
				break;
			case 3:
				printf("Other");
				break;
			default:
				printf("???");
				break;
			}
			if (mca_error & 0x0100)
				printf(" timed out");
			break;
		}

		printf("unknown error %x", mca_error);
		break;
	}
	printf("\n");
	if (rec->mr_status & MC_STATUS_ADDRV)
		printf("MCA: Address 0x%llx\n", (long long)rec->mr_addr);
}

/*
 * This scans all the machine check banks of the current CPU to see if
 * there are any machine checks.  Any non-recoverable errors are
 * reported immediately via mca_log().  The current thread must be
 * pinned when this is called.  The 'mcip' parameter indicates if we
 * are being called from the MC exception handler.  In that case this
 * function returns true if the system is restartable.  Otherwise, it
 * returns a count of the number of valid MC records found.
 */
static int
mca_scan(int mcip)
{
	struct mca_record *rec;
	uint64_t mcg_cap, ucmask;
	int count, i, recoverable;

	count = 0;
	recoverable = 1;
	ucmask = MC_STATUS_UC | MC_STATUS_PCC;

	/* When handling a MCE#, treat the OVER flag as non-restartable. */
	if (mcip)
		ucmask |= MC_STATUS_OVER;
	mcg_cap = rdmsr(MSR_MCG_CAP);
	for (i = 0; i < (mcg_cap & MCG_CAP_COUNT); i++) {
		rec = mca_record_entry(i);
		if (rec != NULL) {
			count++;
			if (rec->mr_status & ucmask) {
				recoverable = 0;
				mca_log(rec);
			}
		}
	}
	return (mcip ? recoverable : count);
}

/*
 * Scan the machine check banks on all CPUs by binding to each CPU in
 * turn.  If any of the CPUs contained new machine check records, log
 * them to the console.
 */
static void
mca_scan_cpus(void *context, int pending)
{
	struct mca_internal *mca;
	struct thread *td;
	int count, cpu;

	td = curthread;
	count = 0;
	thread_lock(td);
	for (cpu = 0; cpu <= mp_maxid; cpu++) {
		if (CPU_ABSENT(cpu))
			continue;
		sched_bind(td, cpu);
		thread_unlock(td);
		count += mca_scan(0);
		thread_lock(td);
		sched_unbind(td);
	}
	thread_unlock(td);
	if (count != 0) {
		mtx_lock_spin(&mca_lock);
		STAILQ_FOREACH(mca, &mca_records, link) {
			if (!mca->logged) {
				mca->logged = 1;
				mtx_unlock_spin(&mca_lock);
				mca_log(&mca->rec);
				mtx_lock_spin(&mca_lock);
			}
		}
		mtx_unlock_spin(&mca_lock);
	}
}

static void
mca_periodic_scan(void *arg)
{

	taskqueue_enqueue(taskqueue_thread, &mca_task);
	callout_reset(&mca_timer, mca_ticks * hz, mca_periodic_scan, NULL);
}

static int
sysctl_mca_scan(SYSCTL_HANDLER_ARGS)
{
	int error, i;

	i = 0;
	error = sysctl_handle_int(oidp, &i, 0, req);
	if (error)
		return (error);
	if (i)
		taskqueue_enqueue(taskqueue_thread, &mca_task);
	return (0);
}

static void
mca_startup(void *dummy)
{

	if (!mca_enabled || !(cpu_feature & CPUID_MCA))
		return;

	callout_reset(&mca_timer, mca_ticks * hz, mca_periodic_scan,
		    NULL);
}
SYSINIT(mca_startup, SI_SUB_SMP, SI_ORDER_ANY, mca_startup, NULL);

static void
mca_setup(void)
{

	mtx_init(&mca_lock, "mca", NULL, MTX_SPIN);
	STAILQ_INIT(&mca_records);
	TASK_INIT(&mca_task, 0x8000, mca_scan_cpus, NULL);
	callout_init(&mca_timer, CALLOUT_MPSAFE);
	SYSCTL_ADD_INT(NULL, SYSCTL_STATIC_CHILDREN(_hw_mca), OID_AUTO,
	    "count", CTLFLAG_RD, &mca_count, 0, "Record count");
	SYSCTL_ADD_PROC(NULL, SYSCTL_STATIC_CHILDREN(_hw_mca), OID_AUTO,
	    "interval", CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, &mca_ticks,
	    0, sysctl_mca_ticks, "I",
	    "Periodic interval in seconds to scan for machine checks");
	SYSCTL_ADD_NODE(NULL, SYSCTL_STATIC_CHILDREN(_hw_mca), OID_AUTO,
	    "records", CTLFLAG_RD, sysctl_mca_records, "Machine check records");
	SYSCTL_ADD_PROC(NULL, SYSCTL_STATIC_CHILDREN(_hw_mca), OID_AUTO,
	    "force_scan", CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, NULL, 0,
	    sysctl_mca_scan, "I", "Force an immediate scan for machine checks");
}

/* Must be executed on each CPU. */
void
mca_init(void)
{
	uint64_t mcg_cap;
	int i;

	/* MCE is required. */
	if (!mca_enabled || !(cpu_feature & CPUID_MCE))
		return;

	if (cpu_feature & CPUID_MCA) {
		if (PCPU_GET(cpuid) == 0)
			mca_setup();

		sched_pin();
		mcg_cap = rdmsr(MSR_MCG_CAP);
		if (mcg_cap & MCG_CAP_CTL_P)
			/* Enable MCA features. */
			wrmsr(MSR_MCG_CTL, MCG_CTL_ENABLE);

		for (i = 0; i < (mcg_cap & MCG_CAP_COUNT); i++) {
			/*
			 * Enable logging of all errors.  For P6
			 * processors, MC0_CTL is always enabled.
			 *
			 * XXX: Better CPU test needed here?
			 */
			if (!(i == 0 && (cpu_id & 0xf00) == 0x600))
				wrmsr(MSR_MC_CTL(i), 0xffffffffffffffffUL);

			/* Clear all errors. */
			wrmsr(MSR_MC_STATUS(i), 0);
		}
		sched_unpin();
	}

	load_cr4(rcr4() | CR4_MCE);
}

/* Called when a machine check exception fires. */
int
mca_intr(void)
{
	uint64_t mcg_status;
	int recoverable;

	if (!(cpu_feature & CPUID_MCA)) {
		/*
		 * Just print the values of the old Pentium registers
		 * and panic.
		 */
		printf("MC Type: 0x%llx  Address: 0x%llx\n",
		    rdmsr(MSR_P5_MC_TYPE), rdmsr(MSR_P5_MC_ADDR));
		return (0);
	}

	/* Scan the banks and check for any non-recoverable errors. */
	recoverable = mca_scan(1);
	mcg_status = rdmsr(MSR_MCG_STATUS);
	if (!(mcg_status & MCG_STATUS_RIPV))
		recoverable = 0;

	/* Clear MCIP. */
	wrmsr(MSR_MCG_STATUS, mcg_status & ~MCG_STATUS_MCIP);
	return (recoverable);
}