xref: /freebsd/sys/x86/x86/mca.c (revision e17f5b1d)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2009 Hudson River Trading LLC
5  * Written by: John H. Baldwin <jhb@FreeBSD.org>
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 /*
31  * Support for x86 machine check architecture.
32  */
33 
34 #include <sys/cdefs.h>
35 __FBSDID("$FreeBSD$");
36 
37 #ifdef __amd64__
38 #define	DEV_APIC
39 #else
40 #include "opt_apic.h"
41 #endif
42 
43 #include <sys/param.h>
44 #include <sys/bus.h>
45 #include <sys/interrupt.h>
46 #include <sys/kernel.h>
47 #include <sys/lock.h>
48 #include <sys/malloc.h>
49 #include <sys/mutex.h>
50 #include <sys/proc.h>
51 #include <sys/sched.h>
52 #include <sys/smp.h>
53 #include <sys/sysctl.h>
54 #include <sys/systm.h>
55 #include <sys/taskqueue.h>
56 #include <machine/intr_machdep.h>
57 #include <x86/apicvar.h>
58 #include <machine/cpu.h>
59 #include <machine/cputypes.h>
60 #include <x86/mca.h>
61 #include <machine/md_var.h>
62 #include <machine/specialreg.h>
63 
64 /* Modes for mca_scan() */
65 enum scan_mode {
66 	POLLED,
67 	MCE,
68 	CMCI,
69 };
70 
71 #ifdef DEV_APIC
72 /*
73  * State maintained for each monitored MCx bank to control the
74  * corrected machine check interrupt threshold.
75  */
76 struct cmc_state {
77 	int	max_threshold;
78 	time_t	last_intr;
79 };
80 
81 struct amd_et_state {
82 	int	cur_threshold;
83 	time_t	last_intr;
84 };
85 #endif
86 
87 struct mca_internal {
88 	struct mca_record rec;
89 	STAILQ_ENTRY(mca_internal) link;
90 };
91 
92 struct mca_enumerator_ops {
93         unsigned int (*ctl)(int);
94         unsigned int (*status)(int);
95         unsigned int (*addr)(int);
96         unsigned int (*misc)(int);
97 };
98 
99 static MALLOC_DEFINE(M_MCA, "MCA", "Machine Check Architecture");
100 
101 static volatile int mca_count;	/* Number of records stored. */
102 static int mca_banks;		/* Number of per-CPU register banks. */
103 static int mca_maxcount = -1;	/* Limit on records stored. (-1 = unlimited) */
104 
105 static SYSCTL_NODE(_hw, OID_AUTO, mca, CTLFLAG_RD | CTLFLAG_MPSAFE, NULL,
106     "Machine Check Architecture");
107 
108 static int mca_enabled = 1;
109 SYSCTL_INT(_hw_mca, OID_AUTO, enabled, CTLFLAG_RDTUN, &mca_enabled, 0,
110     "Administrative toggle for machine check support");
111 
112 static int amd10h_L1TP = 1;
113 SYSCTL_INT(_hw_mca, OID_AUTO, amd10h_L1TP, CTLFLAG_RDTUN, &amd10h_L1TP, 0,
114     "Administrative toggle for logging of level one TLB parity (L1TP) errors");
115 
116 static int intel6h_HSD131;
117 SYSCTL_INT(_hw_mca, OID_AUTO, intel6h_HSD131, CTLFLAG_RDTUN, &intel6h_HSD131, 0,
118     "Administrative toggle for logging of spurious corrected errors");
119 
120 int workaround_erratum383;
121 SYSCTL_INT(_hw_mca, OID_AUTO, erratum383, CTLFLAG_RDTUN,
122     &workaround_erratum383, 0,
123     "Is the workaround for Erratum 383 on AMD Family 10h processors enabled?");
124 
125 static STAILQ_HEAD(, mca_internal) mca_freelist;
126 static int mca_freecount;
127 static STAILQ_HEAD(, mca_internal) mca_records;
128 static STAILQ_HEAD(, mca_internal) mca_pending;
129 static struct callout mca_timer;
130 static int mca_ticks = 3600;	/* Check hourly by default. */
131 static struct taskqueue *mca_tq;
132 static struct task mca_resize_task, mca_scan_task;
133 static struct mtx mca_lock;
134 
135 static unsigned int
136 mca_ia32_ctl_reg(int bank)
137 {
138 	return (MSR_MC_CTL(bank));
139 }
140 
141 static unsigned int
142 mca_ia32_status_reg(int bank)
143 {
144 	return (MSR_MC_STATUS(bank));
145 }
146 
147 static unsigned int
148 mca_ia32_addr_reg(int bank)
149 {
150 	return (MSR_MC_ADDR(bank));
151 }
152 
153 static unsigned int
154 mca_ia32_misc_reg(int bank)
155 {
156 	return (MSR_MC_MISC(bank));
157 }
158 
159 static unsigned int
160 mca_smca_ctl_reg(int bank)
161 {
162         return (MSR_SMCA_MC_CTL(bank));
163 }
164 
165 static unsigned int
166 mca_smca_status_reg(int bank)
167 {
168         return (MSR_SMCA_MC_STATUS(bank));
169 }
170 
171 static unsigned int
172 mca_smca_addr_reg(int bank)
173 {
174         return (MSR_SMCA_MC_ADDR(bank));
175 }
176 
177 static unsigned int
178 mca_smca_misc_reg(int bank)
179 {
180         return (MSR_SMCA_MC_MISC(bank));
181 }
182 
183 static struct mca_enumerator_ops mca_msr_ops = {
184         .ctl    = mca_ia32_ctl_reg,
185         .status = mca_ia32_status_reg,
186         .addr   = mca_ia32_addr_reg,
187         .misc   = mca_ia32_misc_reg
188 };
189 
190 #ifdef DEV_APIC
191 static struct cmc_state **cmc_state;		/* Indexed by cpuid, bank. */
192 static struct amd_et_state **amd_et_state;	/* Indexed by cpuid, bank. */
193 static int cmc_throttle = 60;	/* Time in seconds to throttle CMCI. */
194 
195 static int amd_elvt = -1;
196 
197 static inline bool
198 amd_thresholding_supported(void)
199 {
200 	if (cpu_vendor_id != CPU_VENDOR_AMD &&
201 	    cpu_vendor_id != CPU_VENDOR_HYGON)
202 		return (false);
203 	/*
204 	 * The RASCap register is wholly reserved in families 0x10-0x15 (through model 1F).
205 	 *
206 	 * It begins to be documented in family 0x15 model 30 and family 0x16,
207 	 * but neither of these families documents the ScalableMca bit, which
208 	 * supposedly defines the presence of this feature on family 0x17.
209 	 */
210 	if (CPUID_TO_FAMILY(cpu_id) >= 0x10 && CPUID_TO_FAMILY(cpu_id) <= 0x16)
211 		return (true);
212 	if (CPUID_TO_FAMILY(cpu_id) >= 0x17)
213 		return ((amd_rascap & AMDRAS_SCALABLE_MCA) != 0);
214 	return (false);
215 }
216 #endif
217 
218 static inline bool
219 cmci_supported(uint64_t mcg_cap)
220 {
221 	/*
222 	 * MCG_CAP_CMCI_P bit is reserved in AMD documentation.  Until
223 	 * it is defined, do not use it to check for CMCI support.
224 	 */
225 	if (cpu_vendor_id != CPU_VENDOR_INTEL)
226 		return (false);
227 	return ((mcg_cap & MCG_CAP_CMCI_P) != 0);
228 }
229 
230 static int
231 sysctl_positive_int(SYSCTL_HANDLER_ARGS)
232 {
233 	int error, value;
234 
235 	value = *(int *)arg1;
236 	error = sysctl_handle_int(oidp, &value, 0, req);
237 	if (error || req->newptr == NULL)
238 		return (error);
239 	if (value <= 0)
240 		return (EINVAL);
241 	*(int *)arg1 = value;
242 	return (0);
243 }
244 
245 static int
246 sysctl_mca_records(SYSCTL_HANDLER_ARGS)
247 {
248 	int *name = (int *)arg1;
249 	u_int namelen = arg2;
250 	struct mca_record record;
251 	struct mca_internal *rec;
252 	int i;
253 
254 	if (namelen != 1)
255 		return (EINVAL);
256 
257 	if (name[0] < 0 || name[0] >= mca_count)
258 		return (EINVAL);
259 
260 	mtx_lock_spin(&mca_lock);
261 	if (name[0] >= mca_count) {
262 		mtx_unlock_spin(&mca_lock);
263 		return (EINVAL);
264 	}
265 	i = 0;
266 	STAILQ_FOREACH(rec, &mca_records, link) {
267 		if (i == name[0]) {
268 			record = rec->rec;
269 			break;
270 		}
271 		i++;
272 	}
273 	mtx_unlock_spin(&mca_lock);
274 	return (SYSCTL_OUT(req, &record, sizeof(record)));
275 }
276 
277 static const char *
278 mca_error_ttype(uint16_t mca_error)
279 {
280 
281 	switch ((mca_error & 0x000c) >> 2) {
282 	case 0:
283 		return ("I");
284 	case 1:
285 		return ("D");
286 	case 2:
287 		return ("G");
288 	}
289 	return ("?");
290 }
291 
292 static const char *
293 mca_error_level(uint16_t mca_error)
294 {
295 
296 	switch (mca_error & 0x0003) {
297 	case 0:
298 		return ("L0");
299 	case 1:
300 		return ("L1");
301 	case 2:
302 		return ("L2");
303 	case 3:
304 		return ("LG");
305 	}
306 	return ("L?");
307 }
308 
309 static const char *
310 mca_error_request(uint16_t mca_error)
311 {
312 
313 	switch ((mca_error & 0x00f0) >> 4) {
314 	case 0x0:
315 		return ("ERR");
316 	case 0x1:
317 		return ("RD");
318 	case 0x2:
319 		return ("WR");
320 	case 0x3:
321 		return ("DRD");
322 	case 0x4:
323 		return ("DWR");
324 	case 0x5:
325 		return ("IRD");
326 	case 0x6:
327 		return ("PREFETCH");
328 	case 0x7:
329 		return ("EVICT");
330 	case 0x8:
331 		return ("SNOOP");
332 	}
333 	return ("???");
334 }
335 
336 static const char *
337 mca_error_mmtype(uint16_t mca_error)
338 {
339 
340 	switch ((mca_error & 0x70) >> 4) {
341 	case 0x0:
342 		return ("GEN");
343 	case 0x1:
344 		return ("RD");
345 	case 0x2:
346 		return ("WR");
347 	case 0x3:
348 		return ("AC");
349 	case 0x4:
350 		return ("MS");
351 	}
352 	return ("???");
353 }
354 
355 static int
356 mca_mute(const struct mca_record *rec)
357 {
358 
359 	/*
360 	 * Skip spurious corrected parity errors generated by Intel Haswell-
361 	 * and Broadwell-based CPUs (see HSD131, HSM142, HSW131 and BDM48
362 	 * erratum respectively), unless reporting is enabled.
363 	 * Note that these errors also have been observed with the D0-stepping
364 	 * of Haswell, while at least initially the CPU specification updates
365 	 * suggested only the C0-stepping to be affected.  Similarly, Celeron
366 	 * 2955U with a CPU ID of 0x45 apparently are also concerned with the
367 	 * same problem, with HSM142 only referring to 0x3c and 0x46.
368 	 */
369 	if (cpu_vendor_id == CPU_VENDOR_INTEL &&
370 	    CPUID_TO_FAMILY(cpu_id) == 0x6 &&
371 	    (CPUID_TO_MODEL(cpu_id) == 0x3c ||	/* HSD131, HSM142, HSW131 */
372 	    CPUID_TO_MODEL(cpu_id) == 0x3d ||	/* BDM48 */
373 	    CPUID_TO_MODEL(cpu_id) == 0x45 ||
374 	    CPUID_TO_MODEL(cpu_id) == 0x46) &&	/* HSM142 */
375 	    rec->mr_bank == 0 &&
376 	    (rec->mr_status & 0xa0000000ffffffff) == 0x80000000000f0005 &&
377 	    !intel6h_HSD131)
378 	    	return (1);
379 
380 	return (0);
381 }
382 
383 /* Dump details about a single machine check. */
384 static void
385 mca_log(const struct mca_record *rec)
386 {
387 	uint16_t mca_error;
388 
389 	if (mca_mute(rec))
390 	    	return;
391 
392 	printf("MCA: Bank %d, Status 0x%016llx\n", rec->mr_bank,
393 	    (long long)rec->mr_status);
394 	printf("MCA: Global Cap 0x%016llx, Status 0x%016llx\n",
395 	    (long long)rec->mr_mcg_cap, (long long)rec->mr_mcg_status);
396 	printf("MCA: Vendor \"%s\", ID 0x%x, APIC ID %d\n", cpu_vendor,
397 	    rec->mr_cpu_id, rec->mr_apic_id);
398 	printf("MCA: CPU %d ", rec->mr_cpu);
399 	if (rec->mr_status & MC_STATUS_UC)
400 		printf("UNCOR ");
401 	else {
402 		printf("COR ");
403 		if (cmci_supported(rec->mr_mcg_cap))
404 			printf("(%lld) ", ((long long)rec->mr_status &
405 			    MC_STATUS_COR_COUNT) >> 38);
406 	}
407 	if (rec->mr_status & MC_STATUS_PCC)
408 		printf("PCC ");
409 	if (rec->mr_status & MC_STATUS_OVER)
410 		printf("OVER ");
411 	mca_error = rec->mr_status & MC_STATUS_MCA_ERROR;
412 	switch (mca_error) {
413 		/* Simple error codes. */
414 	case 0x0000:
415 		printf("no error");
416 		break;
417 	case 0x0001:
418 		printf("unclassified error");
419 		break;
420 	case 0x0002:
421 		printf("ucode ROM parity error");
422 		break;
423 	case 0x0003:
424 		printf("external error");
425 		break;
426 	case 0x0004:
427 		printf("FRC error");
428 		break;
429 	case 0x0005:
430 		printf("internal parity error");
431 		break;
432 	case 0x0400:
433 		printf("internal timer error");
434 		break;
435 	default:
436 		if ((mca_error & 0xfc00) == 0x0400) {
437 			printf("internal error %x", mca_error & 0x03ff);
438 			break;
439 		}
440 
441 		/* Compound error codes. */
442 
443 		/* Memory hierarchy error. */
444 		if ((mca_error & 0xeffc) == 0x000c) {
445 			printf("%s memory error", mca_error_level(mca_error));
446 			break;
447 		}
448 
449 		/* TLB error. */
450 		if ((mca_error & 0xeff0) == 0x0010) {
451 			printf("%sTLB %s error", mca_error_ttype(mca_error),
452 			    mca_error_level(mca_error));
453 			break;
454 		}
455 
456 		/* Memory controller error. */
457 		if ((mca_error & 0xef80) == 0x0080) {
458 			printf("%s channel ", mca_error_mmtype(mca_error));
459 			if ((mca_error & 0x000f) != 0x000f)
460 				printf("%d", mca_error & 0x000f);
461 			else
462 				printf("??");
463 			printf(" memory error");
464 			break;
465 		}
466 
467 		/* Cache error. */
468 		if ((mca_error & 0xef00) == 0x0100) {
469 			printf("%sCACHE %s %s error",
470 			    mca_error_ttype(mca_error),
471 			    mca_error_level(mca_error),
472 			    mca_error_request(mca_error));
473 			break;
474 		}
475 
476 		/* Bus and/or Interconnect error. */
477 		if ((mca_error & 0xe800) == 0x0800) {
478 			printf("BUS%s ", mca_error_level(mca_error));
479 			switch ((mca_error & 0x0600) >> 9) {
480 			case 0:
481 				printf("Source");
482 				break;
483 			case 1:
484 				printf("Responder");
485 				break;
486 			case 2:
487 				printf("Observer");
488 				break;
489 			default:
490 				printf("???");
491 				break;
492 			}
493 			printf(" %s ", mca_error_request(mca_error));
494 			switch ((mca_error & 0x000c) >> 2) {
495 			case 0:
496 				printf("Memory");
497 				break;
498 			case 2:
499 				printf("I/O");
500 				break;
501 			case 3:
502 				printf("Other");
503 				break;
504 			default:
505 				printf("???");
506 				break;
507 			}
508 			if (mca_error & 0x0100)
509 				printf(" timed out");
510 			break;
511 		}
512 
513 		printf("unknown error %x", mca_error);
514 		break;
515 	}
516 	printf("\n");
517 	if (rec->mr_status & MC_STATUS_ADDRV)
518 		printf("MCA: Address 0x%llx\n", (long long)rec->mr_addr);
519 	if (rec->mr_status & MC_STATUS_MISCV)
520 		printf("MCA: Misc 0x%llx\n", (long long)rec->mr_misc);
521 }
522 
523 static int
524 mca_check_status(int bank, struct mca_record *rec)
525 {
526 	uint64_t status;
527 	u_int p[4];
528 
529 	status = rdmsr(mca_msr_ops.status(bank));
530 	if (!(status & MC_STATUS_VAL))
531 		return (0);
532 
533 	/* Save exception information. */
534 	rec->mr_status = status;
535 	rec->mr_bank = bank;
536 	rec->mr_addr = 0;
537 	if (status & MC_STATUS_ADDRV)
538 		rec->mr_addr = rdmsr(mca_msr_ops.addr(bank));
539 	rec->mr_misc = 0;
540 	if (status & MC_STATUS_MISCV)
541 		rec->mr_misc = rdmsr(mca_msr_ops.misc(bank));
542 	rec->mr_tsc = rdtsc();
543 	rec->mr_apic_id = PCPU_GET(apic_id);
544 	rec->mr_mcg_cap = rdmsr(MSR_MCG_CAP);
545 	rec->mr_mcg_status = rdmsr(MSR_MCG_STATUS);
546 	rec->mr_cpu_id = cpu_id;
547 	rec->mr_cpu_vendor_id = cpu_vendor_id;
548 	rec->mr_cpu = PCPU_GET(cpuid);
549 
550 	/*
551 	 * Clear machine check.  Don't do this for uncorrectable
552 	 * errors so that the BIOS can see them.
553 	 */
554 	if (!(rec->mr_status & (MC_STATUS_PCC | MC_STATUS_UC))) {
555 		wrmsr(mca_msr_ops.status(bank), 0);
556 		do_cpuid(0, p);
557 	}
558 	return (1);
559 }
560 
561 static void
562 mca_resize_freelist(void)
563 {
564 	struct mca_internal *next, *rec;
565 	STAILQ_HEAD(, mca_internal) tmplist;
566 	int count, i, desired_max, desired_min;
567 
568 	/*
569 	 * Ensure we have at least one record for each bank and one
570 	 * record per CPU, but no more than twice that amount.
571 	 */
572 	desired_min = imax(mp_ncpus, mca_banks);
573 	desired_max = imax(mp_ncpus, mca_banks) * 2;
574 	STAILQ_INIT(&tmplist);
575 	mtx_lock_spin(&mca_lock);
576 	while (mca_freecount > desired_max) {
577 		rec = STAILQ_FIRST(&mca_freelist);
578 		KASSERT(rec != NULL, ("mca_freecount is %d, but list is empty",
579 		    mca_freecount));
580 		STAILQ_REMOVE_HEAD(&mca_freelist, link);
581 		mca_freecount--;
582 		STAILQ_INSERT_TAIL(&tmplist, rec, link);
583 	}
584 	while (mca_freecount < desired_min) {
585 		count = desired_min - mca_freecount;
586 		mtx_unlock_spin(&mca_lock);
587 		for (i = 0; i < count; i++) {
588 			rec = malloc(sizeof(*rec), M_MCA, M_WAITOK);
589 			STAILQ_INSERT_TAIL(&tmplist, rec, link);
590 		}
591 		mtx_lock_spin(&mca_lock);
592 		STAILQ_CONCAT(&mca_freelist, &tmplist);
593 		mca_freecount += count;
594 	}
595 	mtx_unlock_spin(&mca_lock);
596 	STAILQ_FOREACH_SAFE(rec, &tmplist, link, next)
597 		free(rec, M_MCA);
598 }
599 
600 static void
601 mca_resize(void *context, int pending)
602 {
603 
604 	mca_resize_freelist();
605 }
606 
607 static void
608 mca_record_entry(enum scan_mode mode, const struct mca_record *record)
609 {
610 	struct mca_internal *rec;
611 
612 	if (mode == POLLED) {
613 		rec = malloc(sizeof(*rec), M_MCA, M_WAITOK);
614 		mtx_lock_spin(&mca_lock);
615 	} else {
616 		mtx_lock_spin(&mca_lock);
617 		rec = STAILQ_FIRST(&mca_freelist);
618 		if (rec == NULL) {
619 			printf("MCA: Unable to allocate space for an event.\n");
620 			mca_log(record);
621 			mtx_unlock_spin(&mca_lock);
622 			return;
623 		}
624 		STAILQ_REMOVE_HEAD(&mca_freelist, link);
625 		mca_freecount--;
626 	}
627 
628 	rec->rec = *record;
629 	STAILQ_INSERT_TAIL(&mca_pending, rec, link);
630 	mtx_unlock_spin(&mca_lock);
631 }
632 
633 #ifdef DEV_APIC
634 /*
635  * Update the interrupt threshold for a CMCI.  The strategy is to use
636  * a low trigger that interrupts as soon as the first event occurs.
637  * However, if a steady stream of events arrive, the threshold is
638  * increased until the interrupts are throttled to once every
639  * cmc_throttle seconds or the periodic scan.  If a periodic scan
640  * finds that the threshold is too high, it is lowered.
641  */
642 static int
643 update_threshold(enum scan_mode mode, int valid, int last_intr, int count,
644     int cur_threshold, int max_threshold)
645 {
646 	u_int delta;
647 	int limit;
648 
649 	delta = (u_int)(time_uptime - last_intr);
650 	limit = cur_threshold;
651 
652 	/*
653 	 * If an interrupt was received less than cmc_throttle seconds
654 	 * since the previous interrupt and the count from the current
655 	 * event is greater than or equal to the current threshold,
656 	 * double the threshold up to the max.
657 	 */
658 	if (mode == CMCI && valid) {
659 		if (delta < cmc_throttle && count >= limit &&
660 		    limit < max_threshold) {
661 			limit = min(limit << 1, max_threshold);
662 		}
663 		return (limit);
664 	}
665 
666 	/*
667 	 * When the banks are polled, check to see if the threshold
668 	 * should be lowered.
669 	 */
670 	if (mode != POLLED)
671 		return (limit);
672 
673 	/* If a CMCI occured recently, do nothing for now. */
674 	if (delta < cmc_throttle)
675 		return (limit);
676 
677 	/*
678 	 * Compute a new limit based on the average rate of events per
679 	 * cmc_throttle seconds since the last interrupt.
680 	 */
681 	if (valid) {
682 		limit = count * cmc_throttle / delta;
683 		if (limit <= 0)
684 			limit = 1;
685 		else if (limit > max_threshold)
686 			limit = max_threshold;
687 	} else {
688 		limit = 1;
689 	}
690 	return (limit);
691 }
692 
693 static void
694 cmci_update(enum scan_mode mode, int bank, int valid, struct mca_record *rec)
695 {
696 	struct cmc_state *cc;
697 	uint64_t ctl;
698 	int cur_threshold, new_threshold;
699 	int count;
700 
701 	/* Fetch the current limit for this bank. */
702 	cc = &cmc_state[PCPU_GET(cpuid)][bank];
703 	ctl = rdmsr(MSR_MC_CTL2(bank));
704 	count = (rec->mr_status & MC_STATUS_COR_COUNT) >> 38;
705 	cur_threshold = ctl & MC_CTL2_THRESHOLD;
706 
707 	new_threshold = update_threshold(mode, valid, cc->last_intr, count,
708 	    cur_threshold, cc->max_threshold);
709 
710 	if (mode == CMCI && valid)
711 		cc->last_intr = time_uptime;
712 	if (new_threshold != cur_threshold) {
713 		ctl &= ~MC_CTL2_THRESHOLD;
714 		ctl |= new_threshold;
715 		wrmsr(MSR_MC_CTL2(bank), ctl);
716 	}
717 }
718 
719 static void
720 amd_thresholding_update(enum scan_mode mode, int bank, int valid)
721 {
722 	struct amd_et_state *cc;
723 	uint64_t misc;
724 	int new_threshold;
725 	int count;
726 
727 	cc = &amd_et_state[PCPU_GET(cpuid)][bank];
728 	misc = rdmsr(mca_msr_ops.misc(bank));
729 	count = (misc & MC_MISC_AMD_CNT_MASK) >> MC_MISC_AMD_CNT_SHIFT;
730 	count = count - (MC_MISC_AMD_CNT_MAX - cc->cur_threshold);
731 
732 	new_threshold = update_threshold(mode, valid, cc->last_intr, count,
733 	    cc->cur_threshold, MC_MISC_AMD_CNT_MAX);
734 
735 	cc->cur_threshold = new_threshold;
736 	misc &= ~MC_MISC_AMD_CNT_MASK;
737 	misc |= (uint64_t)(MC_MISC_AMD_CNT_MAX - cc->cur_threshold)
738 	    << MC_MISC_AMD_CNT_SHIFT;
739 	misc &= ~MC_MISC_AMD_OVERFLOW;
740 	wrmsr(mca_msr_ops.misc(bank), misc);
741 	if (mode == CMCI && valid)
742 		cc->last_intr = time_uptime;
743 }
744 #endif
745 
746 /*
747  * This scans all the machine check banks of the current CPU to see if
748  * there are any machine checks.  Any non-recoverable errors are
749  * reported immediately via mca_log().  The current thread must be
750  * pinned when this is called.  The 'mode' parameter indicates if we
751  * are being called from the MC exception handler, the CMCI handler,
752  * or the periodic poller.  In the MC exception case this function
753  * returns true if the system is restartable.  Otherwise, it returns a
754  * count of the number of valid MC records found.
755  */
756 static int
757 mca_scan(enum scan_mode mode, int *recoverablep)
758 {
759 	struct mca_record rec;
760 	uint64_t mcg_cap, ucmask;
761 	int count, i, recoverable, valid;
762 
763 	count = 0;
764 	recoverable = 1;
765 	ucmask = MC_STATUS_UC | MC_STATUS_PCC;
766 
767 	/* When handling a MCE#, treat the OVER flag as non-restartable. */
768 	if (mode == MCE)
769 		ucmask |= MC_STATUS_OVER;
770 	mcg_cap = rdmsr(MSR_MCG_CAP);
771 	for (i = 0; i < (mcg_cap & MCG_CAP_COUNT); i++) {
772 #ifdef DEV_APIC
773 		/*
774 		 * For a CMCI, only check banks this CPU is
775 		 * responsible for.
776 		 */
777 		if (mode == CMCI && !(PCPU_GET(cmci_mask) & 1 << i))
778 			continue;
779 #endif
780 
781 		valid = mca_check_status(i, &rec);
782 		if (valid) {
783 			count++;
784 			if (rec.mr_status & ucmask) {
785 				recoverable = 0;
786 				mtx_lock_spin(&mca_lock);
787 				mca_log(&rec);
788 				mtx_unlock_spin(&mca_lock);
789 			}
790 			mca_record_entry(mode, &rec);
791 		}
792 
793 #ifdef DEV_APIC
794 		/*
795 		 * If this is a bank this CPU monitors via CMCI,
796 		 * update the threshold.
797 		 */
798 		if (PCPU_GET(cmci_mask) & 1 << i) {
799 			if (cmc_state != NULL)
800 				cmci_update(mode, i, valid, &rec);
801 			else
802 				amd_thresholding_update(mode, i, valid);
803 		}
804 #endif
805 	}
806 	if (recoverablep != NULL)
807 		*recoverablep = recoverable;
808 	return (count);
809 }
810 
811 /*
812  * Store a new record on the mca_records list while enforcing
813  * mca_maxcount.
814  */
815 static void
816 mca_store_record(struct mca_internal *mca)
817 {
818 
819 	/*
820 	 * If we are storing no records (mca_maxcount == 0),
821 	 * we just free this record.
822 	 *
823 	 * If we are storing records (mca_maxcount != 0) and
824 	 * we have free space on the list, store the record
825 	 * and increment mca_count.
826 	 *
827 	 * If we are storing records and we do not have free
828 	 * space on the list, store the new record at the
829 	 * tail and free the oldest one from the head.
830 	 */
831 	if (mca_maxcount != 0)
832 		STAILQ_INSERT_TAIL(&mca_records, mca, link);
833 	if (mca_maxcount < 0 || mca_count < mca_maxcount)
834 		mca_count++;
835 	else {
836 		if (mca_maxcount != 0) {
837 			mca = STAILQ_FIRST(&mca_records);
838 			STAILQ_REMOVE_HEAD(&mca_records, link);
839 		}
840 		STAILQ_INSERT_TAIL(&mca_freelist, mca, link);
841 		mca_freecount++;
842 	}
843 }
844 
845 /*
846  * Do the work to process machine check records which have just been
847  * gathered. Print any pending logs to the console. Queue them for storage.
848  * Trigger a resizing of the free list.
849  */
850 static void
851 mca_process_records(enum scan_mode mode)
852 {
853 	struct mca_internal *mca;
854 
855 	mtx_lock_spin(&mca_lock);
856 	while ((mca = STAILQ_FIRST(&mca_pending)) != NULL) {
857 		STAILQ_REMOVE_HEAD(&mca_pending, link);
858 		mca_log(&mca->rec);
859 		mca_store_record(mca);
860 	}
861 	mtx_unlock_spin(&mca_lock);
862 	if (mode == POLLED)
863 		mca_resize_freelist();
864 	else if (!cold)
865 		taskqueue_enqueue(mca_tq, &mca_resize_task);
866 }
867 
868 /*
869  * Scan the machine check banks on all CPUs by binding to each CPU in
870  * turn.  If any of the CPUs contained new machine check records, log
871  * them to the console.
872  */
873 static void
874 mca_scan_cpus(void *context, int pending)
875 {
876 	struct thread *td;
877 	int count, cpu;
878 
879 	mca_resize_freelist();
880 	td = curthread;
881 	count = 0;
882 	thread_lock(td);
883 	CPU_FOREACH(cpu) {
884 		sched_bind(td, cpu);
885 		thread_unlock(td);
886 		count += mca_scan(POLLED, NULL);
887 		thread_lock(td);
888 		sched_unbind(td);
889 	}
890 	thread_unlock(td);
891 	if (count != 0)
892 		mca_process_records(POLLED);
893 }
894 
895 static void
896 mca_periodic_scan(void *arg)
897 {
898 
899 	taskqueue_enqueue(mca_tq, &mca_scan_task);
900 	callout_reset(&mca_timer, mca_ticks * hz, mca_periodic_scan, NULL);
901 }
902 
903 static int
904 sysctl_mca_scan(SYSCTL_HANDLER_ARGS)
905 {
906 	int error, i;
907 
908 	i = 0;
909 	error = sysctl_handle_int(oidp, &i, 0, req);
910 	if (error)
911 		return (error);
912 	if (i)
913 		taskqueue_enqueue(mca_tq, &mca_scan_task);
914 	return (0);
915 }
916 
917 static int
918 sysctl_mca_maxcount(SYSCTL_HANDLER_ARGS)
919 {
920 	struct mca_internal *mca;
921 	int error, i;
922 	bool doresize;
923 
924 	i = mca_maxcount;
925 	error = sysctl_handle_int(oidp, &i, 0, req);
926 	if (error || req->newptr == NULL)
927 		return (error);
928 	mtx_lock_spin(&mca_lock);
929 	mca_maxcount = i;
930 	doresize = false;
931 	if (mca_maxcount >= 0)
932 		while (mca_count > mca_maxcount) {
933 			mca = STAILQ_FIRST(&mca_records);
934 			STAILQ_REMOVE_HEAD(&mca_records, link);
935 			mca_count--;
936 			STAILQ_INSERT_TAIL(&mca_freelist, mca, link);
937 			mca_freecount++;
938 			doresize = true;
939 		}
940 	mtx_unlock_spin(&mca_lock);
941 	if (doresize && !cold)
942 		taskqueue_enqueue(mca_tq, &mca_resize_task);
943 	return (error);
944 }
945 
946 static void
947 mca_createtq(void *dummy)
948 {
949 	if (mca_banks <= 0)
950 		return;
951 
952 	mca_tq = taskqueue_create_fast("mca", M_WAITOK,
953 	    taskqueue_thread_enqueue, &mca_tq);
954 	taskqueue_start_threads(&mca_tq, 1, PI_SWI(SWI_TQ), "mca taskq");
955 
956 	/* CMCIs during boot may have claimed items from the freelist. */
957 	mca_resize_freelist();
958 }
959 SYSINIT(mca_createtq, SI_SUB_CONFIGURE, SI_ORDER_ANY, mca_createtq, NULL);
960 
961 static void
962 mca_startup(void *dummy)
963 {
964 
965 	if (mca_banks <= 0)
966 		return;
967 
968 	callout_reset(&mca_timer, mca_ticks * hz, mca_periodic_scan, NULL);
969 }
970 #ifdef EARLY_AP_STARTUP
971 SYSINIT(mca_startup, SI_SUB_KICK_SCHEDULER, SI_ORDER_ANY, mca_startup, NULL);
972 #else
973 SYSINIT(mca_startup, SI_SUB_SMP, SI_ORDER_ANY, mca_startup, NULL);
974 #endif
975 
976 #ifdef DEV_APIC
977 static void
978 cmci_setup(void)
979 {
980 	int i;
981 
982 	cmc_state = malloc((mp_maxid + 1) * sizeof(struct cmc_state *), M_MCA,
983 	    M_WAITOK);
984 	for (i = 0; i <= mp_maxid; i++)
985 		cmc_state[i] = malloc(sizeof(struct cmc_state) * mca_banks,
986 		    M_MCA, M_WAITOK | M_ZERO);
987 	SYSCTL_ADD_PROC(NULL, SYSCTL_STATIC_CHILDREN(_hw_mca), OID_AUTO,
988 	    "cmc_throttle", CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
989 	    &cmc_throttle, 0, sysctl_positive_int, "I",
990 	    "Interval in seconds to throttle corrected MC interrupts");
991 }
992 
993 static void
994 amd_thresholding_setup(void)
995 {
996 	u_int i;
997 
998 	amd_et_state = malloc((mp_maxid + 1) * sizeof(struct amd_et_state *),
999 	    M_MCA, M_WAITOK);
1000 	for (i = 0; i <= mp_maxid; i++)
1001 		amd_et_state[i] = malloc(sizeof(struct amd_et_state) *
1002 		    mca_banks, M_MCA, M_WAITOK | M_ZERO);
1003 	SYSCTL_ADD_PROC(NULL, SYSCTL_STATIC_CHILDREN(_hw_mca), OID_AUTO,
1004 	    "cmc_throttle", CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
1005 	    &cmc_throttle, 0, sysctl_positive_int, "I",
1006 	    "Interval in seconds to throttle corrected MC interrupts");
1007 }
1008 #endif
1009 
1010 static void
1011 mca_setup(uint64_t mcg_cap)
1012 {
1013 
1014 	/*
1015 	 * On AMD Family 10h processors, unless logging of level one TLB
1016 	 * parity (L1TP) errors is disabled, enable the recommended workaround
1017 	 * for Erratum 383.
1018 	 */
1019 	if (cpu_vendor_id == CPU_VENDOR_AMD &&
1020 	    CPUID_TO_FAMILY(cpu_id) == 0x10 && amd10h_L1TP)
1021 		workaround_erratum383 = 1;
1022 
1023 	mca_banks = mcg_cap & MCG_CAP_COUNT;
1024 	mtx_init(&mca_lock, "mca", NULL, MTX_SPIN);
1025 	STAILQ_INIT(&mca_records);
1026 	STAILQ_INIT(&mca_pending);
1027 	TASK_INIT(&mca_scan_task, 0, mca_scan_cpus, NULL);
1028 	callout_init(&mca_timer, 1);
1029 	STAILQ_INIT(&mca_freelist);
1030 	TASK_INIT(&mca_resize_task, 0, mca_resize, NULL);
1031 	mca_resize_freelist();
1032 	SYSCTL_ADD_INT(NULL, SYSCTL_STATIC_CHILDREN(_hw_mca), OID_AUTO,
1033 	    "count", CTLFLAG_RD, (int *)(uintptr_t)&mca_count, 0,
1034 	    "Record count");
1035 	SYSCTL_ADD_PROC(NULL, SYSCTL_STATIC_CHILDREN(_hw_mca), OID_AUTO,
1036 	    "maxcount", CTLTYPE_INT | CTLFLAG_RWTUN | CTLFLAG_MPSAFE,
1037 	    &mca_maxcount, 0, sysctl_mca_maxcount, "I",
1038 	    "Maximum record count (-1 is unlimited)");
1039 	SYSCTL_ADD_PROC(NULL, SYSCTL_STATIC_CHILDREN(_hw_mca), OID_AUTO,
1040 	    "interval", CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, &mca_ticks,
1041 	    0, sysctl_positive_int, "I",
1042 	    "Periodic interval in seconds to scan for machine checks");
1043 	SYSCTL_ADD_NODE(NULL, SYSCTL_STATIC_CHILDREN(_hw_mca), OID_AUTO,
1044 	    "records", CTLFLAG_RD | CTLFLAG_MPSAFE, sysctl_mca_records,
1045 	    "Machine check records");
1046 	SYSCTL_ADD_PROC(NULL, SYSCTL_STATIC_CHILDREN(_hw_mca), OID_AUTO,
1047 	    "force_scan", CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, NULL, 0,
1048 	    sysctl_mca_scan, "I", "Force an immediate scan for machine checks");
1049 #ifdef DEV_APIC
1050 	if (cmci_supported(mcg_cap))
1051 		cmci_setup();
1052 	else if (amd_thresholding_supported())
1053 		amd_thresholding_setup();
1054 #endif
1055 }
1056 
1057 #ifdef DEV_APIC
1058 /*
1059  * See if we should monitor CMCI for this bank.  If CMCI_EN is already
1060  * set in MC_CTL2, then another CPU is responsible for this bank, so
1061  * ignore it.  If CMCI_EN returns zero after being set, then this bank
1062  * does not support CMCI_EN.  If this CPU sets CMCI_EN, then it should
1063  * now monitor this bank.
1064  */
1065 static void
1066 cmci_monitor(int i)
1067 {
1068 	struct cmc_state *cc;
1069 	uint64_t ctl;
1070 
1071 	KASSERT(i < mca_banks, ("CPU %d has more MC banks", PCPU_GET(cpuid)));
1072 
1073 	ctl = rdmsr(MSR_MC_CTL2(i));
1074 	if (ctl & MC_CTL2_CMCI_EN)
1075 		/* Already monitored by another CPU. */
1076 		return;
1077 
1078 	/* Set the threshold to one event for now. */
1079 	ctl &= ~MC_CTL2_THRESHOLD;
1080 	ctl |= MC_CTL2_CMCI_EN | 1;
1081 	wrmsr(MSR_MC_CTL2(i), ctl);
1082 	ctl = rdmsr(MSR_MC_CTL2(i));
1083 	if (!(ctl & MC_CTL2_CMCI_EN))
1084 		/* This bank does not support CMCI. */
1085 		return;
1086 
1087 	cc = &cmc_state[PCPU_GET(cpuid)][i];
1088 
1089 	/* Determine maximum threshold. */
1090 	ctl &= ~MC_CTL2_THRESHOLD;
1091 	ctl |= 0x7fff;
1092 	wrmsr(MSR_MC_CTL2(i), ctl);
1093 	ctl = rdmsr(MSR_MC_CTL2(i));
1094 	cc->max_threshold = ctl & MC_CTL2_THRESHOLD;
1095 
1096 	/* Start off with a threshold of 1. */
1097 	ctl &= ~MC_CTL2_THRESHOLD;
1098 	ctl |= 1;
1099 	wrmsr(MSR_MC_CTL2(i), ctl);
1100 
1101 	/* Mark this bank as monitored. */
1102 	PCPU_SET(cmci_mask, PCPU_GET(cmci_mask) | 1 << i);
1103 }
1104 
1105 /*
1106  * For resume, reset the threshold for any banks we monitor back to
1107  * one and throw away the timestamp of the last interrupt.
1108  */
1109 static void
1110 cmci_resume(int i)
1111 {
1112 	struct cmc_state *cc;
1113 	uint64_t ctl;
1114 
1115 	KASSERT(i < mca_banks, ("CPU %d has more MC banks", PCPU_GET(cpuid)));
1116 
1117 	/* Ignore banks not monitored by this CPU. */
1118 	if (!(PCPU_GET(cmci_mask) & 1 << i))
1119 		return;
1120 
1121 	cc = &cmc_state[PCPU_GET(cpuid)][i];
1122 	cc->last_intr = 0;
1123 	ctl = rdmsr(MSR_MC_CTL2(i));
1124 	ctl &= ~MC_CTL2_THRESHOLD;
1125 	ctl |= MC_CTL2_CMCI_EN | 1;
1126 	wrmsr(MSR_MC_CTL2(i), ctl);
1127 }
1128 
1129 /*
1130  * Apply an AMD ET configuration to the corresponding MSR.
1131  */
1132 static void
1133 amd_thresholding_start(struct amd_et_state *cc, int bank)
1134 {
1135 	uint64_t misc;
1136 
1137 	KASSERT(amd_elvt >= 0, ("ELVT offset is not set"));
1138 
1139 	misc = rdmsr(mca_msr_ops.misc(bank));
1140 
1141 	misc &= ~MC_MISC_AMD_INT_MASK;
1142 	misc |= MC_MISC_AMD_INT_LVT;
1143 
1144 	misc &= ~MC_MISC_AMD_LVT_MASK;
1145 	misc |= (uint64_t)amd_elvt << MC_MISC_AMD_LVT_SHIFT;
1146 
1147 	misc &= ~MC_MISC_AMD_CNT_MASK;
1148 	misc |= (uint64_t)(MC_MISC_AMD_CNT_MAX - cc->cur_threshold)
1149 	    << MC_MISC_AMD_CNT_SHIFT;
1150 
1151 	misc &= ~MC_MISC_AMD_OVERFLOW;
1152 	misc |= MC_MISC_AMD_CNTEN;
1153 
1154 	wrmsr(mca_msr_ops.misc(bank), misc);
1155 }
1156 
1157 static void
1158 amd_thresholding_monitor(int i)
1159 {
1160 	struct amd_et_state *cc;
1161 	uint64_t misc;
1162 
1163 	/*
1164 	 * Kludge: On 10h, banks after 4 are not thresholding but also may have
1165 	 * bogus Valid bits.  Skip them.  This is definitely fixed in 15h, but
1166 	 * I have not investigated whether it is fixed in earlier models.
1167 	 */
1168 	if (CPUID_TO_FAMILY(cpu_id) < 0x15 && i >= 5)
1169 		return;
1170 
1171 	/* The counter must be valid and present. */
1172 	misc = rdmsr(mca_msr_ops.misc(i));
1173 	if ((misc & (MC_MISC_AMD_VAL | MC_MISC_AMD_CNTP)) !=
1174 	    (MC_MISC_AMD_VAL | MC_MISC_AMD_CNTP))
1175 		return;
1176 
1177 	/* The register should not be locked. */
1178 	if ((misc & MC_MISC_AMD_LOCK) != 0) {
1179 		if (bootverbose)
1180 			printf("%s: 0x%jx: Bank %d: locked\n", __func__,
1181 			    (uintmax_t)misc, i);
1182 		return;
1183 	}
1184 
1185 	/*
1186 	 * If counter is enabled then either the firmware or another CPU
1187 	 * has already claimed it.
1188 	 */
1189 	if ((misc & MC_MISC_AMD_CNTEN) != 0) {
1190 		if (bootverbose)
1191 			printf("%s: 0x%jx: Bank %d: already enabled\n",
1192 			    __func__, (uintmax_t)misc, i);
1193 		return;
1194 	}
1195 
1196 	/*
1197 	 * Configure an Extended Interrupt LVT register for reporting
1198 	 * counter overflows if that feature is supported and the first
1199 	 * extended register is available.
1200 	 */
1201 	amd_elvt = lapic_enable_mca_elvt();
1202 	if (amd_elvt < 0) {
1203 		printf("%s: Bank %d: lapic enable mca elvt failed: %d\n",
1204 		    __func__, i, amd_elvt);
1205 		return;
1206 	}
1207 
1208 	/* Re-use Intel CMC support infrastructure. */
1209 	if (bootverbose)
1210 		printf("%s: Starting AMD thresholding on bank %d\n", __func__,
1211 		    i);
1212 
1213 	cc = &amd_et_state[PCPU_GET(cpuid)][i];
1214 	cc->cur_threshold = 1;
1215 	amd_thresholding_start(cc, i);
1216 
1217 	/* Mark this bank as monitored. */
1218 	PCPU_SET(cmci_mask, PCPU_GET(cmci_mask) | 1 << i);
1219 }
1220 
1221 static void
1222 amd_thresholding_resume(int i)
1223 {
1224 	struct amd_et_state *cc;
1225 
1226 	KASSERT(i < mca_banks, ("CPU %d has more MC banks", PCPU_GET(cpuid)));
1227 
1228 	/* Ignore banks not monitored by this CPU. */
1229 	if (!(PCPU_GET(cmci_mask) & 1 << i))
1230 		return;
1231 
1232 	cc = &amd_et_state[PCPU_GET(cpuid)][i];
1233 	cc->last_intr = 0;
1234 	cc->cur_threshold = 1;
1235 	amd_thresholding_start(cc, i);
1236 }
1237 #endif
1238 
1239 /*
1240  * Initializes per-CPU machine check registers and enables corrected
1241  * machine check interrupts.
1242  */
1243 static void
1244 _mca_init(int boot)
1245 {
1246 	uint64_t mcg_cap;
1247 	uint64_t ctl, mask;
1248 	int i, skip, family;
1249 
1250 	family = CPUID_TO_FAMILY(cpu_id);
1251 
1252 	/* MCE is required. */
1253 	if (!mca_enabled || !(cpu_feature & CPUID_MCE))
1254 		return;
1255 
1256 	if (cpu_feature & CPUID_MCA) {
1257 		if (boot)
1258 			PCPU_SET(cmci_mask, 0);
1259 
1260 		mcg_cap = rdmsr(MSR_MCG_CAP);
1261 		if (mcg_cap & MCG_CAP_CTL_P)
1262 			/* Enable MCA features. */
1263 			wrmsr(MSR_MCG_CTL, MCG_CTL_ENABLE);
1264 		if (IS_BSP() && boot)
1265 			mca_setup(mcg_cap);
1266 
1267 		/*
1268 		 * Disable logging of level one TLB parity (L1TP) errors by
1269 		 * the data cache as an alternative workaround for AMD Family
1270 		 * 10h Erratum 383.  Unlike the recommended workaround, there
1271 		 * is no performance penalty to this workaround.  However,
1272 		 * L1TP errors will go unreported.
1273 		 */
1274 		if (cpu_vendor_id == CPU_VENDOR_AMD && family == 0x10 &&
1275 		    !amd10h_L1TP) {
1276 			mask = rdmsr(MSR_MC0_CTL_MASK);
1277 			if ((mask & (1UL << 5)) == 0)
1278 				wrmsr(MSR_MC0_CTL_MASK, mask | (1UL << 5));
1279 		}
1280 		if (amd_rascap & AMDRAS_SCALABLE_MCA) {
1281 			mca_msr_ops.ctl = mca_smca_ctl_reg;
1282 			mca_msr_ops.status = mca_smca_status_reg;
1283 			mca_msr_ops.addr = mca_smca_addr_reg;
1284 			mca_msr_ops.misc = mca_smca_misc_reg;
1285 		}
1286 
1287 		/*
1288 		 * The cmci_monitor() must not be executed
1289 		 * simultaneously by several CPUs.
1290 		 */
1291 		if (boot)
1292 			mtx_lock_spin(&mca_lock);
1293 
1294 		for (i = 0; i < (mcg_cap & MCG_CAP_COUNT); i++) {
1295 			/* By default enable logging of all errors. */
1296 			ctl = 0xffffffffffffffffUL;
1297 			skip = 0;
1298 
1299 			if (cpu_vendor_id == CPU_VENDOR_INTEL) {
1300 				/*
1301 				 * For P6 models before Nehalem MC0_CTL is
1302 				 * always enabled and reserved.
1303 				 */
1304 				if (i == 0 && family == 0x6
1305 				    && CPUID_TO_MODEL(cpu_id) < 0x1a)
1306 					skip = 1;
1307 			} else if (cpu_vendor_id == CPU_VENDOR_AMD) {
1308 				/* BKDG for Family 10h: unset GartTblWkEn. */
1309 				if (i == MC_AMDNB_BANK && family >= 0xf &&
1310 				    family < 0x17)
1311 					ctl &= ~(1UL << 10);
1312 			}
1313 
1314 			if (!skip)
1315 				wrmsr(mca_msr_ops.ctl(i), ctl);
1316 
1317 #ifdef DEV_APIC
1318 			if (cmci_supported(mcg_cap)) {
1319 				if (boot)
1320 					cmci_monitor(i);
1321 				else
1322 					cmci_resume(i);
1323 			} else if (amd_thresholding_supported()) {
1324 				if (boot)
1325 					amd_thresholding_monitor(i);
1326 				else
1327 					amd_thresholding_resume(i);
1328 			}
1329 #endif
1330 
1331 			/* Clear all errors. */
1332 			wrmsr(mca_msr_ops.status(i), 0);
1333 		}
1334 		if (boot)
1335 			mtx_unlock_spin(&mca_lock);
1336 
1337 #ifdef DEV_APIC
1338 		if (!amd_thresholding_supported() &&
1339 		    PCPU_GET(cmci_mask) != 0 && boot)
1340 			lapic_enable_cmc();
1341 #endif
1342 	}
1343 
1344 	load_cr4(rcr4() | CR4_MCE);
1345 }
1346 
1347 /* Must be executed on each CPU during boot. */
1348 void
1349 mca_init(void)
1350 {
1351 
1352 	_mca_init(1);
1353 }
1354 
1355 /* Must be executed on each CPU during resume. */
1356 void
1357 mca_resume(void)
1358 {
1359 
1360 	_mca_init(0);
1361 }
1362 
1363 /*
1364  * The machine check registers for the BSP cannot be initialized until
1365  * the local APIC is initialized.  This happens at SI_SUB_CPU,
1366  * SI_ORDER_SECOND.
1367  */
1368 static void
1369 mca_init_bsp(void *arg __unused)
1370 {
1371 
1372 	mca_init();
1373 }
1374 SYSINIT(mca_init_bsp, SI_SUB_CPU, SI_ORDER_ANY, mca_init_bsp, NULL);
1375 
1376 /* Called when a machine check exception fires. */
1377 void
1378 mca_intr(void)
1379 {
1380 	uint64_t mcg_status;
1381 	int recoverable, count;
1382 
1383 	if (!(cpu_feature & CPUID_MCA)) {
1384 		/*
1385 		 * Just print the values of the old Pentium registers
1386 		 * and panic.
1387 		 */
1388 		printf("MC Type: 0x%jx  Address: 0x%jx\n",
1389 		    (uintmax_t)rdmsr(MSR_P5_MC_TYPE),
1390 		    (uintmax_t)rdmsr(MSR_P5_MC_ADDR));
1391 		panic("Machine check");
1392 	}
1393 
1394 	/* Scan the banks and check for any non-recoverable errors. */
1395 	count = mca_scan(MCE, &recoverable);
1396 	mcg_status = rdmsr(MSR_MCG_STATUS);
1397 	if (!(mcg_status & MCG_STATUS_RIPV))
1398 		recoverable = 0;
1399 
1400 	if (!recoverable) {
1401 		/*
1402 		 * Only panic if the error was detected local to this CPU.
1403 		 * Some errors will assert a machine check on all CPUs, but
1404 		 * only certain CPUs will find a valid bank to log.
1405 		 */
1406 		while (count == 0)
1407 			cpu_spinwait();
1408 
1409 		panic("Unrecoverable machine check exception");
1410 	}
1411 
1412 	/* Clear MCIP. */
1413 	wrmsr(MSR_MCG_STATUS, mcg_status & ~MCG_STATUS_MCIP);
1414 }
1415 
1416 #ifdef DEV_APIC
1417 /* Called for a CMCI (correctable machine check interrupt). */
1418 void
1419 cmc_intr(void)
1420 {
1421 
1422 	/*
1423 	 * Serialize MCA bank scanning to prevent collisions from
1424 	 * sibling threads.
1425 	 *
1426 	 * If we found anything, log them to the console.
1427 	 */
1428 	if (mca_scan(CMCI, NULL) != 0)
1429 		mca_process_records(CMCI);
1430 }
1431 #endif
1432