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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Machine check exception handling.
4 *
5 * Copyright 2013 IBM Corporation
6 * Author: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
7 */
8
9#undef DEBUG
10#define pr_fmt(fmt) "mce: " fmt
11
12#include <linux/hardirq.h>
13#include <linux/types.h>
14#include <linux/ptrace.h>
15#include <linux/percpu.h>
16#include <linux/export.h>
17#include <linux/irq_work.h>
18#include <linux/extable.h>
19#include <linux/ftrace.h>
20#include <linux/memblock.h>
21#include <linux/of.h>
22
23#include <asm/interrupt.h>
24#include <asm/machdep.h>
25#include <asm/mce.h>
26#include <asm/nmi.h>
27
28#include "setup.h"
29
30static void machine_check_ue_event(struct machine_check_event *evt);
31static void machine_process_ue_event(struct work_struct *work);
32
33static DECLARE_WORK(mce_ue_event_work, machine_process_ue_event);
34
35static BLOCKING_NOTIFIER_HEAD(mce_notifier_list);
36
37int mce_register_notifier(struct notifier_block *nb)
38{
39 return blocking_notifier_chain_register(&mce_notifier_list, nb);
40}
41EXPORT_SYMBOL_GPL(mce_register_notifier);
42
43int mce_unregister_notifier(struct notifier_block *nb)
44{
45 return blocking_notifier_chain_unregister(&mce_notifier_list, nb);
46}
47EXPORT_SYMBOL_GPL(mce_unregister_notifier);
48
49static void mce_set_error_info(struct machine_check_event *mce,
50 struct mce_error_info *mce_err)
51{
52 mce->error_type = mce_err->error_type;
53 switch (mce_err->error_type) {
54 case MCE_ERROR_TYPE_UE:
55 mce->u.ue_error.ue_error_type = mce_err->u.ue_error_type;
56 break;
57 case MCE_ERROR_TYPE_SLB:
58 mce->u.slb_error.slb_error_type = mce_err->u.slb_error_type;
59 break;
60 case MCE_ERROR_TYPE_ERAT:
61 mce->u.erat_error.erat_error_type = mce_err->u.erat_error_type;
62 break;
63 case MCE_ERROR_TYPE_TLB:
64 mce->u.tlb_error.tlb_error_type = mce_err->u.tlb_error_type;
65 break;
66 case MCE_ERROR_TYPE_USER:
67 mce->u.user_error.user_error_type = mce_err->u.user_error_type;
68 break;
69 case MCE_ERROR_TYPE_RA:
70 mce->u.ra_error.ra_error_type = mce_err->u.ra_error_type;
71 break;
72 case MCE_ERROR_TYPE_LINK:
73 mce->u.link_error.link_error_type = mce_err->u.link_error_type;
74 break;
75 case MCE_ERROR_TYPE_UNKNOWN:
76 default:
77 break;
78 }
79}
80
81void mce_irq_work_queue(void)
82{
83 /* Raise decrementer interrupt */
84 arch_irq_work_raise();
85 set_mce_pending_irq_work();
86}
87
88/*
89 * Decode and save high level MCE information into per cpu buffer which
90 * is an array of machine_check_event structure.
91 */
92void save_mce_event(struct pt_regs *regs, long handled,
93 struct mce_error_info *mce_err,
94 uint64_t nip, uint64_t addr, uint64_t phys_addr)
95{
96 int index = local_paca->mce_info->mce_nest_count++;
97 struct machine_check_event *mce;
98
99 mce = &local_paca->mce_info->mce_event[index];
100 /*
101 * Return if we don't have enough space to log mce event.
102 * mce_nest_count may go beyond MAX_MC_EVT but that's ok,
103 * the check below will stop buffer overrun.
104 */
105 if (index >= MAX_MC_EVT)
106 return;
107
108 /* Populate generic machine check info */
109 mce->version = MCE_V1;
110 mce->srr0 = nip;
111 mce->srr1 = regs->msr;
112 mce->gpr3 = regs->gpr[3];
113 mce->in_use = 1;
114 mce->cpu = get_paca()->paca_index;
115
116 /* Mark it recovered if we have handled it and MSR(RI=1). */
117 if (handled && (regs->msr & MSR_RI))
118 mce->disposition = MCE_DISPOSITION_RECOVERED;
119 else
120 mce->disposition = MCE_DISPOSITION_NOT_RECOVERED;
121
122 mce->initiator = mce_err->initiator;
123 mce->severity = mce_err->severity;
124 mce->sync_error = mce_err->sync_error;
125 mce->error_class = mce_err->error_class;
126
127 /*
128 * Populate the mce error_type and type-specific error_type.
129 */
130 mce_set_error_info(mce, mce_err);
131 if (mce->error_type == MCE_ERROR_TYPE_UE)
132 mce->u.ue_error.ignore_event = mce_err->ignore_event;
133
134 /*
135 * Raise irq work, So that we don't miss to log the error for
136 * unrecoverable errors.
137 */
138 if (mce->disposition == MCE_DISPOSITION_NOT_RECOVERED)
139 mce_irq_work_queue();
140
141 if (!addr)
142 return;
143
144 if (mce->error_type == MCE_ERROR_TYPE_TLB) {
145 mce->u.tlb_error.effective_address_provided = true;
146 mce->u.tlb_error.effective_address = addr;
147 } else if (mce->error_type == MCE_ERROR_TYPE_SLB) {
148 mce->u.slb_error.effective_address_provided = true;
149 mce->u.slb_error.effective_address = addr;
150 } else if (mce->error_type == MCE_ERROR_TYPE_ERAT) {
151 mce->u.erat_error.effective_address_provided = true;
152 mce->u.erat_error.effective_address = addr;
153 } else if (mce->error_type == MCE_ERROR_TYPE_USER) {
154 mce->u.user_error.effective_address_provided = true;
155 mce->u.user_error.effective_address = addr;
156 } else if (mce->error_type == MCE_ERROR_TYPE_RA) {
157 mce->u.ra_error.effective_address_provided = true;
158 mce->u.ra_error.effective_address = addr;
159 } else if (mce->error_type == MCE_ERROR_TYPE_LINK) {
160 mce->u.link_error.effective_address_provided = true;
161 mce->u.link_error.effective_address = addr;
162 } else if (mce->error_type == MCE_ERROR_TYPE_UE) {
163 mce->u.ue_error.effective_address_provided = true;
164 mce->u.ue_error.effective_address = addr;
165 if (phys_addr != ULONG_MAX) {
166 mce->u.ue_error.physical_address_provided = true;
167 mce->u.ue_error.physical_address = phys_addr;
168 machine_check_ue_event(mce);
169 }
170 }
171 return;
172}
173
174/*
175 * get_mce_event:
176 * mce Pointer to machine_check_event structure to be filled.
177 * release Flag to indicate whether to free the event slot or not.
178 * 0 <= do not release the mce event. Caller will invoke
179 * release_mce_event() once event has been consumed.
180 * 1 <= release the slot.
181 *
182 * return 1 = success
183 * 0 = failure
184 *
185 * get_mce_event() will be called by platform specific machine check
186 * handle routine and in KVM.
187 * When we call get_mce_event(), we are still in interrupt context and
188 * preemption will not be scheduled until ret_from_expect() routine
189 * is called.
190 */
191int get_mce_event(struct machine_check_event *mce, bool release)
192{
193 int index = local_paca->mce_info->mce_nest_count - 1;
194 struct machine_check_event *mc_evt;
195 int ret = 0;
196
197 /* Sanity check */
198 if (index < 0)
199 return ret;
200
201 /* Check if we have MCE info to process. */
202 if (index < MAX_MC_EVT) {
203 mc_evt = &local_paca->mce_info->mce_event[index];
204 /* Copy the event structure and release the original */
205 if (mce)
206 *mce = *mc_evt;
207 if (release)
208 mc_evt->in_use = 0;
209 ret = 1;
210 }
211 /* Decrement the count to free the slot. */
212 if (release)
213 local_paca->mce_info->mce_nest_count--;
214
215 return ret;
216}
217
218void release_mce_event(void)
219{
220 get_mce_event(NULL, true);
221}
222
223static void machine_check_ue_work(void)
224{
225 schedule_work(&mce_ue_event_work);
226}
227
228/*
229 * Queue up the MCE event which then can be handled later.
230 */
231static void machine_check_ue_event(struct machine_check_event *evt)
232{
233 int index;
234
235 index = local_paca->mce_info->mce_ue_count++;
236 /* If queue is full, just return for now. */
237 if (index >= MAX_MC_EVT) {
238 local_paca->mce_info->mce_ue_count--;
239 return;
240 }
241 memcpy(&local_paca->mce_info->mce_ue_event_queue[index],
242 evt, sizeof(*evt));
243}
244
245/*
246 * Queue up the MCE event which then can be handled later.
247 */
248void machine_check_queue_event(void)
249{
250 int index;
251 struct machine_check_event evt;
252
253 if (!get_mce_event(&evt, MCE_EVENT_RELEASE))
254 return;
255
256 index = local_paca->mce_info->mce_queue_count++;
257 /* If queue is full, just return for now. */
258 if (index >= MAX_MC_EVT) {
259 local_paca->mce_info->mce_queue_count--;
260 return;
261 }
262 memcpy(&local_paca->mce_info->mce_event_queue[index],
263 &evt, sizeof(evt));
264
265 mce_irq_work_queue();
266}
267
268void mce_common_process_ue(struct pt_regs *regs,
269 struct mce_error_info *mce_err)
270{
271 const struct exception_table_entry *entry;
272
273 entry = search_kernel_exception_table(regs->nip);
274 if (entry) {
275 mce_err->ignore_event = true;
276 regs_set_return_ip(regs, extable_fixup(entry));
277 }
278}
279
280/*
281 * process pending MCE event from the mce event queue. This function will be
282 * called during syscall exit.
283 */
284static void machine_process_ue_event(struct work_struct *work)
285{
286 int index;
287 struct machine_check_event *evt;
288
289 while (local_paca->mce_info->mce_ue_count > 0) {
290 index = local_paca->mce_info->mce_ue_count - 1;
291 evt = &local_paca->mce_info->mce_ue_event_queue[index];
292 blocking_notifier_call_chain(&mce_notifier_list, 0, evt);
293#ifdef CONFIG_MEMORY_FAILURE
294 /*
295 * This should probably queued elsewhere, but
296 * oh! well
297 *
298 * Don't report this machine check because the caller has a
299 * asked us to ignore the event, it has a fixup handler which
300 * will do the appropriate error handling and reporting.
301 */
302 if (evt->error_type == MCE_ERROR_TYPE_UE) {
303 if (evt->u.ue_error.ignore_event) {
304 local_paca->mce_info->mce_ue_count--;
305 continue;
306 }
307
308 if (evt->u.ue_error.physical_address_provided) {
309 unsigned long pfn;
310
311 pfn = evt->u.ue_error.physical_address >>
312 PAGE_SHIFT;
313 memory_failure(pfn, 0);
314 } else
315 pr_warn("Failed to identify bad address from "
316 "where the uncorrectable error (UE) "
317 "was generated\n");
318 }
319#endif
320 local_paca->mce_info->mce_ue_count--;
321 }
322}
323/*
324 * process pending MCE event from the mce event queue. This function will be
325 * called during syscall exit.
326 */
327static void machine_check_process_queued_event(void)
328{
329 int index;
330 struct machine_check_event *evt;
331
332 add_taint(TAINT_MACHINE_CHECK, LOCKDEP_NOW_UNRELIABLE);
333
334 /*
335 * For now just print it to console.
336 * TODO: log this error event to FSP or nvram.
337 */
338 while (local_paca->mce_info->mce_queue_count > 0) {
339 index = local_paca->mce_info->mce_queue_count - 1;
340 evt = &local_paca->mce_info->mce_event_queue[index];
341
342 if (evt->error_type == MCE_ERROR_TYPE_UE &&
343 evt->u.ue_error.ignore_event) {
344 local_paca->mce_info->mce_queue_count--;
345 continue;
346 }
347 machine_check_print_event_info(evt, false, false);
348 local_paca->mce_info->mce_queue_count--;
349 }
350}
351
352void set_mce_pending_irq_work(void)
353{
354 local_paca->mce_pending_irq_work = 1;
355}
356
357void clear_mce_pending_irq_work(void)
358{
359 local_paca->mce_pending_irq_work = 0;
360}
361
362void mce_run_irq_context_handlers(void)
363{
364 if (unlikely(local_paca->mce_pending_irq_work)) {
365 if (ppc_md.machine_check_log_err)
366 ppc_md.machine_check_log_err();
367 machine_check_process_queued_event();
368 machine_check_ue_work();
369 clear_mce_pending_irq_work();
370 }
371}
372
373void machine_check_print_event_info(struct machine_check_event *evt,
374 bool user_mode, bool in_guest)
375{
376 const char *level, *sevstr, *subtype, *err_type, *initiator;
377 uint64_t ea = 0, pa = 0;
378 int n = 0;
379 char dar_str[50];
380 char pa_str[50];
381 static const char *mc_ue_types[] = {
382 "Indeterminate",
383 "Instruction fetch",
384 "Page table walk ifetch",
385 "Load/Store",
386 "Page table walk Load/Store",
387 };
388 static const char *mc_slb_types[] = {
389 "Indeterminate",
390 "Parity",
391 "Multihit",
392 };
393 static const char *mc_erat_types[] = {
394 "Indeterminate",
395 "Parity",
396 "Multihit",
397 };
398 static const char *mc_tlb_types[] = {
399 "Indeterminate",
400 "Parity",
401 "Multihit",
402 };
403 static const char *mc_user_types[] = {
404 "Indeterminate",
405 "tlbie(l) invalid",
406 "scv invalid",
407 };
408 static const char *mc_ra_types[] = {
409 "Indeterminate",
410 "Instruction fetch (bad)",
411 "Instruction fetch (foreign/control memory)",
412 "Page table walk ifetch (bad)",
413 "Page table walk ifetch (foreign/control memory)",
414 "Load (bad)",
415 "Store (bad)",
416 "Page table walk Load/Store (bad)",
417 "Page table walk Load/Store (foreign/control memory)",
418 "Load/Store (foreign/control memory)",
419 };
420 static const char *mc_link_types[] = {
421 "Indeterminate",
422 "Instruction fetch (timeout)",
423 "Page table walk ifetch (timeout)",
424 "Load (timeout)",
425 "Store (timeout)",
426 "Page table walk Load/Store (timeout)",
427 };
428 static const char *mc_error_class[] = {
429 "Unknown",
430 "Hardware error",
431 "Probable Hardware error (some chance of software cause)",
432 "Software error",
433 "Probable Software error (some chance of hardware cause)",
434 };
435
436 /* Print things out */
437 if (evt->version != MCE_V1) {
438 pr_err("Machine Check Exception, Unknown event version %d !\n",
439 evt->version);
440 return;
441 }
442 switch (evt->severity) {
443 case MCE_SEV_NO_ERROR:
444 level = KERN_INFO;
445 sevstr = "Harmless";
446 break;
447 case MCE_SEV_WARNING:
448 level = KERN_WARNING;
449 sevstr = "Warning";
450 break;
451 case MCE_SEV_SEVERE:
452 level = KERN_ERR;
453 sevstr = "Severe";
454 break;
455 case MCE_SEV_FATAL:
456 default:
457 level = KERN_ERR;
458 sevstr = "Fatal";
459 break;
460 }
461
462 switch(evt->initiator) {
463 case MCE_INITIATOR_CPU:
464 initiator = "CPU";
465 break;
466 case MCE_INITIATOR_PCI:
467 initiator = "PCI";
468 break;
469 case MCE_INITIATOR_ISA:
470 initiator = "ISA";
471 break;
472 case MCE_INITIATOR_MEMORY:
473 initiator = "Memory";
474 break;
475 case MCE_INITIATOR_POWERMGM:
476 initiator = "Power Management";
477 break;
478 case MCE_INITIATOR_UNKNOWN:
479 default:
480 initiator = "Unknown";
481 break;
482 }
483
484 switch (evt->error_type) {
485 case MCE_ERROR_TYPE_UE:
486 err_type = "UE";
487 subtype = evt->u.ue_error.ue_error_type <
488 ARRAY_SIZE(mc_ue_types) ?
489 mc_ue_types[evt->u.ue_error.ue_error_type]
490 : "Unknown";
491 if (evt->u.ue_error.effective_address_provided)
492 ea = evt->u.ue_error.effective_address;
493 if (evt->u.ue_error.physical_address_provided)
494 pa = evt->u.ue_error.physical_address;
495 break;
496 case MCE_ERROR_TYPE_SLB:
497 err_type = "SLB";
498 subtype = evt->u.slb_error.slb_error_type <
499 ARRAY_SIZE(mc_slb_types) ?
500 mc_slb_types[evt->u.slb_error.slb_error_type]
501 : "Unknown";
502 if (evt->u.slb_error.effective_address_provided)
503 ea = evt->u.slb_error.effective_address;
504 break;
505 case MCE_ERROR_TYPE_ERAT:
506 err_type = "ERAT";
507 subtype = evt->u.erat_error.erat_error_type <
508 ARRAY_SIZE(mc_erat_types) ?
509 mc_erat_types[evt->u.erat_error.erat_error_type]
510 : "Unknown";
511 if (evt->u.erat_error.effective_address_provided)
512 ea = evt->u.erat_error.effective_address;
513 break;
514 case MCE_ERROR_TYPE_TLB:
515 err_type = "TLB";
516 subtype = evt->u.tlb_error.tlb_error_type <
517 ARRAY_SIZE(mc_tlb_types) ?
518 mc_tlb_types[evt->u.tlb_error.tlb_error_type]
519 : "Unknown";
520 if (evt->u.tlb_error.effective_address_provided)
521 ea = evt->u.tlb_error.effective_address;
522 break;
523 case MCE_ERROR_TYPE_USER:
524 err_type = "User";
525 subtype = evt->u.user_error.user_error_type <
526 ARRAY_SIZE(mc_user_types) ?
527 mc_user_types[evt->u.user_error.user_error_type]
528 : "Unknown";
529 if (evt->u.user_error.effective_address_provided)
530 ea = evt->u.user_error.effective_address;
531 break;
532 case MCE_ERROR_TYPE_RA:
533 err_type = "Real address";
534 subtype = evt->u.ra_error.ra_error_type <
535 ARRAY_SIZE(mc_ra_types) ?
536 mc_ra_types[evt->u.ra_error.ra_error_type]
537 : "Unknown";
538 if (evt->u.ra_error.effective_address_provided)
539 ea = evt->u.ra_error.effective_address;
540 break;
541 case MCE_ERROR_TYPE_LINK:
542 err_type = "Link";
543 subtype = evt->u.link_error.link_error_type <
544 ARRAY_SIZE(mc_link_types) ?
545 mc_link_types[evt->u.link_error.link_error_type]
546 : "Unknown";
547 if (evt->u.link_error.effective_address_provided)
548 ea = evt->u.link_error.effective_address;
549 break;
550 case MCE_ERROR_TYPE_DCACHE:
551 err_type = "D-Cache";
552 subtype = "Unknown";
553 break;
554 case MCE_ERROR_TYPE_ICACHE:
555 err_type = "I-Cache";
556 subtype = "Unknown";
557 break;
558 default:
559 case MCE_ERROR_TYPE_UNKNOWN:
560 err_type = "Unknown";
561 subtype = "";
562 break;
563 }
564
565 dar_str[0] = pa_str[0] = '\0';
566 if (ea && evt->srr0 != ea) {
567 /* Load/Store address */
568 n = sprintf(dar_str, "DAR: %016llx ", ea);
569 if (pa)
570 sprintf(dar_str + n, "paddr: %016llx ", pa);
571 } else if (pa) {
572 sprintf(pa_str, " paddr: %016llx", pa);
573 }
574
575 printk("%sMCE: CPU%d: machine check (%s) %s %s %s %s[%s]\n",
576 level, evt->cpu, sevstr, in_guest ? "Guest" : "",
577 err_type, subtype, dar_str,
578 evt->disposition == MCE_DISPOSITION_RECOVERED ?
579 "Recovered" : "Not recovered");
580
581 if (in_guest || user_mode) {
582 printk("%sMCE: CPU%d: PID: %d Comm: %s %sNIP: [%016llx]%s\n",
583 level, evt->cpu, current->pid, current->comm,
584 in_guest ? "Guest " : "", evt->srr0, pa_str);
585 } else {
586 printk("%sMCE: CPU%d: NIP: [%016llx] %pS%s\n",
587 level, evt->cpu, evt->srr0, (void *)evt->srr0, pa_str);
588 }
589
590 printk("%sMCE: CPU%d: Initiator %s\n", level, evt->cpu, initiator);
591
592 subtype = evt->error_class < ARRAY_SIZE(mc_error_class) ?
593 mc_error_class[evt->error_class] : "Unknown";
594 printk("%sMCE: CPU%d: %s\n", level, evt->cpu, subtype);
595
596#ifdef CONFIG_PPC_64S_HASH_MMU
597 /* Display faulty slb contents for SLB errors. */
598 if (evt->error_type == MCE_ERROR_TYPE_SLB && !in_guest)
599 slb_dump_contents(local_paca->mce_faulty_slbs);
600#endif
601}
602EXPORT_SYMBOL_GPL(machine_check_print_event_info);
603
604/*
605 * This function is called in real mode. Strictly no printk's please.
606 *
607 * regs->nip and regs->msr contains srr0 and ssr1.
608 */
609DEFINE_INTERRUPT_HANDLER_NMI(machine_check_early)
610{
611 long handled = 0;
612
613 hv_nmi_check_nonrecoverable(regs);
614
615 /*
616 * See if platform is capable of handling machine check.
617 */
618 if (ppc_md.machine_check_early)
619 handled = ppc_md.machine_check_early(regs);
620
621 return handled;
622}
623
624/* Possible meanings for HMER_DEBUG_TRIG bit being set on POWER9 */
625static enum {
626 DTRIG_UNKNOWN,
627 DTRIG_VECTOR_CI, /* need to emulate vector CI load instr */
628 DTRIG_SUSPEND_ESCAPE, /* need to escape from TM suspend mode */
629} hmer_debug_trig_function;
630
631static int init_debug_trig_function(void)
632{
633 int pvr;
634 struct device_node *cpun;
635 struct property *prop = NULL;
636 const char *str;
637
638 /* First look in the device tree */
639 preempt_disable();
640 cpun = of_get_cpu_node(smp_processor_id(), NULL);
641 if (cpun) {
642 of_property_for_each_string(cpun, "ibm,hmi-special-triggers",
643 prop, str) {
644 if (strcmp(str, "bit17-vector-ci-load") == 0)
645 hmer_debug_trig_function = DTRIG_VECTOR_CI;
646 else if (strcmp(str, "bit17-tm-suspend-escape") == 0)
647 hmer_debug_trig_function = DTRIG_SUSPEND_ESCAPE;
648 }
649 of_node_put(cpun);
650 }
651 preempt_enable();
652
653 /* If we found the property, don't look at PVR */
654 if (prop)
655 goto out;
656
657 pvr = mfspr(SPRN_PVR);
658 /* Check for POWER9 Nimbus (scale-out) */
659 if ((PVR_VER(pvr) == PVR_POWER9) && (pvr & 0xe000) == 0) {
660 /* DD2.2 and later */
661 if ((pvr & 0xfff) >= 0x202)
662 hmer_debug_trig_function = DTRIG_SUSPEND_ESCAPE;
663 /* DD2.0 and DD2.1 - used for vector CI load emulation */
664 else if ((pvr & 0xfff) >= 0x200)
665 hmer_debug_trig_function = DTRIG_VECTOR_CI;
666 }
667
668 out:
669 switch (hmer_debug_trig_function) {
670 case DTRIG_VECTOR_CI:
671 pr_debug("HMI debug trigger used for vector CI load\n");
672 break;
673 case DTRIG_SUSPEND_ESCAPE:
674 pr_debug("HMI debug trigger used for TM suspend escape\n");
675 break;
676 default:
677 break;
678 }
679 return 0;
680}
681__initcall(init_debug_trig_function);
682
683/*
684 * Handle HMIs that occur as a result of a debug trigger.
685 * Return values:
686 * -1 means this is not a HMI cause that we know about
687 * 0 means no further handling is required
688 * 1 means further handling is required
689 */
690long hmi_handle_debugtrig(struct pt_regs *regs)
691{
692 unsigned long hmer = mfspr(SPRN_HMER);
693 long ret = 0;
694
695 /* HMER_DEBUG_TRIG bit is used for various workarounds on P9 */
696 if (!((hmer & HMER_DEBUG_TRIG)
697 && hmer_debug_trig_function != DTRIG_UNKNOWN))
698 return -1;
699
700 hmer &= ~HMER_DEBUG_TRIG;
701 /* HMER is a write-AND register */
702 mtspr(SPRN_HMER, ~HMER_DEBUG_TRIG);
703
704 switch (hmer_debug_trig_function) {
705 case DTRIG_VECTOR_CI:
706 /*
707 * Now to avoid problems with soft-disable we
708 * only do the emulation if we are coming from
709 * host user space
710 */
711 if (regs && user_mode(regs))
712 ret = local_paca->hmi_p9_special_emu = 1;
713
714 break;
715
716 default:
717 break;
718 }
719
720 /*
721 * See if any other HMI causes remain to be handled
722 */
723 if (hmer & mfspr(SPRN_HMEER))
724 return -1;
725
726 return ret;
727}
728
729/*
730 * Return values:
731 */
732DEFINE_INTERRUPT_HANDLER_NMI(hmi_exception_realmode)
733{
734 int ret;
735
736 local_paca->hmi_irqs++;
737
738 ret = hmi_handle_debugtrig(regs);
739 if (ret >= 0)
740 return ret;
741
742 wait_for_subcore_guest_exit();
743
744 if (ppc_md.hmi_exception_early)
745 ppc_md.hmi_exception_early(regs);
746
747 wait_for_tb_resync();
748
749 return 1;
750}
751
752void __init mce_init(void)
753{
754 struct mce_info *mce_info;
755 u64 limit;
756 int i;
757
758 limit = min(ppc64_bolted_size(), ppc64_rma_size);
759 for_each_possible_cpu(i) {
760 mce_info = memblock_alloc_try_nid(sizeof(*mce_info),
761 __alignof__(*mce_info),
762 MEMBLOCK_LOW_LIMIT,
763 limit, early_cpu_to_node(i));
764 if (!mce_info)
765 goto err;
766 paca_ptrs[i]->mce_info = mce_info;
767 }
768 return;
769err:
770 panic("Failed to allocate memory for MCE event data\n");
771}
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Machine check exception handling.
4 *
5 * Copyright 2013 IBM Corporation
6 * Author: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
7 */
8
9#undef DEBUG
10#define pr_fmt(fmt) "mce: " fmt
11
12#include <linux/hardirq.h>
13#include <linux/types.h>
14#include <linux/ptrace.h>
15#include <linux/percpu.h>
16#include <linux/export.h>
17#include <linux/irq_work.h>
18#include <linux/extable.h>
19#include <linux/ftrace.h>
20
21#include <asm/machdep.h>
22#include <asm/mce.h>
23#include <asm/nmi.h>
24
25static DEFINE_PER_CPU(int, mce_nest_count);
26static DEFINE_PER_CPU(struct machine_check_event[MAX_MC_EVT], mce_event);
27
28/* Queue for delayed MCE events. */
29static DEFINE_PER_CPU(int, mce_queue_count);
30static DEFINE_PER_CPU(struct machine_check_event[MAX_MC_EVT], mce_event_queue);
31
32/* Queue for delayed MCE UE events. */
33static DEFINE_PER_CPU(int, mce_ue_count);
34static DEFINE_PER_CPU(struct machine_check_event[MAX_MC_EVT],
35 mce_ue_event_queue);
36
37static void machine_check_process_queued_event(struct irq_work *work);
38static void machine_check_ue_irq_work(struct irq_work *work);
39static void machine_check_ue_event(struct machine_check_event *evt);
40static void machine_process_ue_event(struct work_struct *work);
41
42static struct irq_work mce_event_process_work = {
43 .func = machine_check_process_queued_event,
44};
45
46static struct irq_work mce_ue_event_irq_work = {
47 .func = machine_check_ue_irq_work,
48};
49
50DECLARE_WORK(mce_ue_event_work, machine_process_ue_event);
51
52static BLOCKING_NOTIFIER_HEAD(mce_notifier_list);
53
54int mce_register_notifier(struct notifier_block *nb)
55{
56 return blocking_notifier_chain_register(&mce_notifier_list, nb);
57}
58EXPORT_SYMBOL_GPL(mce_register_notifier);
59
60int mce_unregister_notifier(struct notifier_block *nb)
61{
62 return blocking_notifier_chain_unregister(&mce_notifier_list, nb);
63}
64EXPORT_SYMBOL_GPL(mce_unregister_notifier);
65
66static void mce_set_error_info(struct machine_check_event *mce,
67 struct mce_error_info *mce_err)
68{
69 mce->error_type = mce_err->error_type;
70 switch (mce_err->error_type) {
71 case MCE_ERROR_TYPE_UE:
72 mce->u.ue_error.ue_error_type = mce_err->u.ue_error_type;
73 break;
74 case MCE_ERROR_TYPE_SLB:
75 mce->u.slb_error.slb_error_type = mce_err->u.slb_error_type;
76 break;
77 case MCE_ERROR_TYPE_ERAT:
78 mce->u.erat_error.erat_error_type = mce_err->u.erat_error_type;
79 break;
80 case MCE_ERROR_TYPE_TLB:
81 mce->u.tlb_error.tlb_error_type = mce_err->u.tlb_error_type;
82 break;
83 case MCE_ERROR_TYPE_USER:
84 mce->u.user_error.user_error_type = mce_err->u.user_error_type;
85 break;
86 case MCE_ERROR_TYPE_RA:
87 mce->u.ra_error.ra_error_type = mce_err->u.ra_error_type;
88 break;
89 case MCE_ERROR_TYPE_LINK:
90 mce->u.link_error.link_error_type = mce_err->u.link_error_type;
91 break;
92 case MCE_ERROR_TYPE_UNKNOWN:
93 default:
94 break;
95 }
96}
97
98/*
99 * Decode and save high level MCE information into per cpu buffer which
100 * is an array of machine_check_event structure.
101 */
102void save_mce_event(struct pt_regs *regs, long handled,
103 struct mce_error_info *mce_err,
104 uint64_t nip, uint64_t addr, uint64_t phys_addr)
105{
106 int index = __this_cpu_inc_return(mce_nest_count) - 1;
107 struct machine_check_event *mce = this_cpu_ptr(&mce_event[index]);
108
109 /*
110 * Return if we don't have enough space to log mce event.
111 * mce_nest_count may go beyond MAX_MC_EVT but that's ok,
112 * the check below will stop buffer overrun.
113 */
114 if (index >= MAX_MC_EVT)
115 return;
116
117 /* Populate generic machine check info */
118 mce->version = MCE_V1;
119 mce->srr0 = nip;
120 mce->srr1 = regs->msr;
121 mce->gpr3 = regs->gpr[3];
122 mce->in_use = 1;
123 mce->cpu = get_paca()->paca_index;
124
125 /* Mark it recovered if we have handled it and MSR(RI=1). */
126 if (handled && (regs->msr & MSR_RI))
127 mce->disposition = MCE_DISPOSITION_RECOVERED;
128 else
129 mce->disposition = MCE_DISPOSITION_NOT_RECOVERED;
130
131 mce->initiator = mce_err->initiator;
132 mce->severity = mce_err->severity;
133 mce->sync_error = mce_err->sync_error;
134 mce->error_class = mce_err->error_class;
135
136 /*
137 * Populate the mce error_type and type-specific error_type.
138 */
139 mce_set_error_info(mce, mce_err);
140
141 if (!addr)
142 return;
143
144 if (mce->error_type == MCE_ERROR_TYPE_TLB) {
145 mce->u.tlb_error.effective_address_provided = true;
146 mce->u.tlb_error.effective_address = addr;
147 } else if (mce->error_type == MCE_ERROR_TYPE_SLB) {
148 mce->u.slb_error.effective_address_provided = true;
149 mce->u.slb_error.effective_address = addr;
150 } else if (mce->error_type == MCE_ERROR_TYPE_ERAT) {
151 mce->u.erat_error.effective_address_provided = true;
152 mce->u.erat_error.effective_address = addr;
153 } else if (mce->error_type == MCE_ERROR_TYPE_USER) {
154 mce->u.user_error.effective_address_provided = true;
155 mce->u.user_error.effective_address = addr;
156 } else if (mce->error_type == MCE_ERROR_TYPE_RA) {
157 mce->u.ra_error.effective_address_provided = true;
158 mce->u.ra_error.effective_address = addr;
159 } else if (mce->error_type == MCE_ERROR_TYPE_LINK) {
160 mce->u.link_error.effective_address_provided = true;
161 mce->u.link_error.effective_address = addr;
162 } else if (mce->error_type == MCE_ERROR_TYPE_UE) {
163 mce->u.ue_error.effective_address_provided = true;
164 mce->u.ue_error.effective_address = addr;
165 if (phys_addr != ULONG_MAX) {
166 mce->u.ue_error.physical_address_provided = true;
167 mce->u.ue_error.physical_address = phys_addr;
168 mce->u.ue_error.ignore_event = mce_err->ignore_event;
169 machine_check_ue_event(mce);
170 }
171 }
172 return;
173}
174
175/*
176 * get_mce_event:
177 * mce Pointer to machine_check_event structure to be filled.
178 * release Flag to indicate whether to free the event slot or not.
179 * 0 <= do not release the mce event. Caller will invoke
180 * release_mce_event() once event has been consumed.
181 * 1 <= release the slot.
182 *
183 * return 1 = success
184 * 0 = failure
185 *
186 * get_mce_event() will be called by platform specific machine check
187 * handle routine and in KVM.
188 * When we call get_mce_event(), we are still in interrupt context and
189 * preemption will not be scheduled until ret_from_expect() routine
190 * is called.
191 */
192int get_mce_event(struct machine_check_event *mce, bool release)
193{
194 int index = __this_cpu_read(mce_nest_count) - 1;
195 struct machine_check_event *mc_evt;
196 int ret = 0;
197
198 /* Sanity check */
199 if (index < 0)
200 return ret;
201
202 /* Check if we have MCE info to process. */
203 if (index < MAX_MC_EVT) {
204 mc_evt = this_cpu_ptr(&mce_event[index]);
205 /* Copy the event structure and release the original */
206 if (mce)
207 *mce = *mc_evt;
208 if (release)
209 mc_evt->in_use = 0;
210 ret = 1;
211 }
212 /* Decrement the count to free the slot. */
213 if (release)
214 __this_cpu_dec(mce_nest_count);
215
216 return ret;
217}
218
219void release_mce_event(void)
220{
221 get_mce_event(NULL, true);
222}
223
224static void machine_check_ue_irq_work(struct irq_work *work)
225{
226 schedule_work(&mce_ue_event_work);
227}
228
229/*
230 * Queue up the MCE event which then can be handled later.
231 */
232static void machine_check_ue_event(struct machine_check_event *evt)
233{
234 int index;
235
236 index = __this_cpu_inc_return(mce_ue_count) - 1;
237 /* If queue is full, just return for now. */
238 if (index >= MAX_MC_EVT) {
239 __this_cpu_dec(mce_ue_count);
240 return;
241 }
242 memcpy(this_cpu_ptr(&mce_ue_event_queue[index]), evt, sizeof(*evt));
243
244 /* Queue work to process this event later. */
245 irq_work_queue(&mce_ue_event_irq_work);
246}
247
248/*
249 * Queue up the MCE event which then can be handled later.
250 */
251void machine_check_queue_event(void)
252{
253 int index;
254 struct machine_check_event evt;
255
256 if (!get_mce_event(&evt, MCE_EVENT_RELEASE))
257 return;
258
259 index = __this_cpu_inc_return(mce_queue_count) - 1;
260 /* If queue is full, just return for now. */
261 if (index >= MAX_MC_EVT) {
262 __this_cpu_dec(mce_queue_count);
263 return;
264 }
265 memcpy(this_cpu_ptr(&mce_event_queue[index]), &evt, sizeof(evt));
266
267 /* Queue irq work to process this event later. */
268 irq_work_queue(&mce_event_process_work);
269}
270
271void mce_common_process_ue(struct pt_regs *regs,
272 struct mce_error_info *mce_err)
273{
274 const struct exception_table_entry *entry;
275
276 entry = search_kernel_exception_table(regs->nip);
277 if (entry) {
278 mce_err->ignore_event = true;
279 regs->nip = extable_fixup(entry);
280 }
281}
282
283/*
284 * process pending MCE event from the mce event queue. This function will be
285 * called during syscall exit.
286 */
287static void machine_process_ue_event(struct work_struct *work)
288{
289 int index;
290 struct machine_check_event *evt;
291
292 while (__this_cpu_read(mce_ue_count) > 0) {
293 index = __this_cpu_read(mce_ue_count) - 1;
294 evt = this_cpu_ptr(&mce_ue_event_queue[index]);
295 blocking_notifier_call_chain(&mce_notifier_list, 0, evt);
296#ifdef CONFIG_MEMORY_FAILURE
297 /*
298 * This should probably queued elsewhere, but
299 * oh! well
300 *
301 * Don't report this machine check because the caller has a
302 * asked us to ignore the event, it has a fixup handler which
303 * will do the appropriate error handling and reporting.
304 */
305 if (evt->error_type == MCE_ERROR_TYPE_UE) {
306 if (evt->u.ue_error.ignore_event) {
307 __this_cpu_dec(mce_ue_count);
308 continue;
309 }
310
311 if (evt->u.ue_error.physical_address_provided) {
312 unsigned long pfn;
313
314 pfn = evt->u.ue_error.physical_address >>
315 PAGE_SHIFT;
316 memory_failure(pfn, 0);
317 } else
318 pr_warn("Failed to identify bad address from "
319 "where the uncorrectable error (UE) "
320 "was generated\n");
321 }
322#endif
323 __this_cpu_dec(mce_ue_count);
324 }
325}
326/*
327 * process pending MCE event from the mce event queue. This function will be
328 * called during syscall exit.
329 */
330static void machine_check_process_queued_event(struct irq_work *work)
331{
332 int index;
333 struct machine_check_event *evt;
334
335 add_taint(TAINT_MACHINE_CHECK, LOCKDEP_NOW_UNRELIABLE);
336
337 /*
338 * For now just print it to console.
339 * TODO: log this error event to FSP or nvram.
340 */
341 while (__this_cpu_read(mce_queue_count) > 0) {
342 index = __this_cpu_read(mce_queue_count) - 1;
343 evt = this_cpu_ptr(&mce_event_queue[index]);
344
345 if (evt->error_type == MCE_ERROR_TYPE_UE &&
346 evt->u.ue_error.ignore_event) {
347 __this_cpu_dec(mce_queue_count);
348 continue;
349 }
350 machine_check_print_event_info(evt, false, false);
351 __this_cpu_dec(mce_queue_count);
352 }
353}
354
355void machine_check_print_event_info(struct machine_check_event *evt,
356 bool user_mode, bool in_guest)
357{
358 const char *level, *sevstr, *subtype, *err_type, *initiator;
359 uint64_t ea = 0, pa = 0;
360 int n = 0;
361 char dar_str[50];
362 char pa_str[50];
363 static const char *mc_ue_types[] = {
364 "Indeterminate",
365 "Instruction fetch",
366 "Page table walk ifetch",
367 "Load/Store",
368 "Page table walk Load/Store",
369 };
370 static const char *mc_slb_types[] = {
371 "Indeterminate",
372 "Parity",
373 "Multihit",
374 };
375 static const char *mc_erat_types[] = {
376 "Indeterminate",
377 "Parity",
378 "Multihit",
379 };
380 static const char *mc_tlb_types[] = {
381 "Indeterminate",
382 "Parity",
383 "Multihit",
384 };
385 static const char *mc_user_types[] = {
386 "Indeterminate",
387 "tlbie(l) invalid",
388 "scv invalid",
389 };
390 static const char *mc_ra_types[] = {
391 "Indeterminate",
392 "Instruction fetch (bad)",
393 "Instruction fetch (foreign)",
394 "Page table walk ifetch (bad)",
395 "Page table walk ifetch (foreign)",
396 "Load (bad)",
397 "Store (bad)",
398 "Page table walk Load/Store (bad)",
399 "Page table walk Load/Store (foreign)",
400 "Load/Store (foreign)",
401 };
402 static const char *mc_link_types[] = {
403 "Indeterminate",
404 "Instruction fetch (timeout)",
405 "Page table walk ifetch (timeout)",
406 "Load (timeout)",
407 "Store (timeout)",
408 "Page table walk Load/Store (timeout)",
409 };
410 static const char *mc_error_class[] = {
411 "Unknown",
412 "Hardware error",
413 "Probable Hardware error (some chance of software cause)",
414 "Software error",
415 "Probable Software error (some chance of hardware cause)",
416 };
417
418 /* Print things out */
419 if (evt->version != MCE_V1) {
420 pr_err("Machine Check Exception, Unknown event version %d !\n",
421 evt->version);
422 return;
423 }
424 switch (evt->severity) {
425 case MCE_SEV_NO_ERROR:
426 level = KERN_INFO;
427 sevstr = "Harmless";
428 break;
429 case MCE_SEV_WARNING:
430 level = KERN_WARNING;
431 sevstr = "Warning";
432 break;
433 case MCE_SEV_SEVERE:
434 level = KERN_ERR;
435 sevstr = "Severe";
436 break;
437 case MCE_SEV_FATAL:
438 default:
439 level = KERN_ERR;
440 sevstr = "Fatal";
441 break;
442 }
443
444 switch(evt->initiator) {
445 case MCE_INITIATOR_CPU:
446 initiator = "CPU";
447 break;
448 case MCE_INITIATOR_PCI:
449 initiator = "PCI";
450 break;
451 case MCE_INITIATOR_ISA:
452 initiator = "ISA";
453 break;
454 case MCE_INITIATOR_MEMORY:
455 initiator = "Memory";
456 break;
457 case MCE_INITIATOR_POWERMGM:
458 initiator = "Power Management";
459 break;
460 case MCE_INITIATOR_UNKNOWN:
461 default:
462 initiator = "Unknown";
463 break;
464 }
465
466 switch (evt->error_type) {
467 case MCE_ERROR_TYPE_UE:
468 err_type = "UE";
469 subtype = evt->u.ue_error.ue_error_type <
470 ARRAY_SIZE(mc_ue_types) ?
471 mc_ue_types[evt->u.ue_error.ue_error_type]
472 : "Unknown";
473 if (evt->u.ue_error.effective_address_provided)
474 ea = evt->u.ue_error.effective_address;
475 if (evt->u.ue_error.physical_address_provided)
476 pa = evt->u.ue_error.physical_address;
477 break;
478 case MCE_ERROR_TYPE_SLB:
479 err_type = "SLB";
480 subtype = evt->u.slb_error.slb_error_type <
481 ARRAY_SIZE(mc_slb_types) ?
482 mc_slb_types[evt->u.slb_error.slb_error_type]
483 : "Unknown";
484 if (evt->u.slb_error.effective_address_provided)
485 ea = evt->u.slb_error.effective_address;
486 break;
487 case MCE_ERROR_TYPE_ERAT:
488 err_type = "ERAT";
489 subtype = evt->u.erat_error.erat_error_type <
490 ARRAY_SIZE(mc_erat_types) ?
491 mc_erat_types[evt->u.erat_error.erat_error_type]
492 : "Unknown";
493 if (evt->u.erat_error.effective_address_provided)
494 ea = evt->u.erat_error.effective_address;
495 break;
496 case MCE_ERROR_TYPE_TLB:
497 err_type = "TLB";
498 subtype = evt->u.tlb_error.tlb_error_type <
499 ARRAY_SIZE(mc_tlb_types) ?
500 mc_tlb_types[evt->u.tlb_error.tlb_error_type]
501 : "Unknown";
502 if (evt->u.tlb_error.effective_address_provided)
503 ea = evt->u.tlb_error.effective_address;
504 break;
505 case MCE_ERROR_TYPE_USER:
506 err_type = "User";
507 subtype = evt->u.user_error.user_error_type <
508 ARRAY_SIZE(mc_user_types) ?
509 mc_user_types[evt->u.user_error.user_error_type]
510 : "Unknown";
511 if (evt->u.user_error.effective_address_provided)
512 ea = evt->u.user_error.effective_address;
513 break;
514 case MCE_ERROR_TYPE_RA:
515 err_type = "Real address";
516 subtype = evt->u.ra_error.ra_error_type <
517 ARRAY_SIZE(mc_ra_types) ?
518 mc_ra_types[evt->u.ra_error.ra_error_type]
519 : "Unknown";
520 if (evt->u.ra_error.effective_address_provided)
521 ea = evt->u.ra_error.effective_address;
522 break;
523 case MCE_ERROR_TYPE_LINK:
524 err_type = "Link";
525 subtype = evt->u.link_error.link_error_type <
526 ARRAY_SIZE(mc_link_types) ?
527 mc_link_types[evt->u.link_error.link_error_type]
528 : "Unknown";
529 if (evt->u.link_error.effective_address_provided)
530 ea = evt->u.link_error.effective_address;
531 break;
532 case MCE_ERROR_TYPE_DCACHE:
533 err_type = "D-Cache";
534 subtype = "Unknown";
535 break;
536 case MCE_ERROR_TYPE_ICACHE:
537 err_type = "I-Cache";
538 subtype = "Unknown";
539 break;
540 default:
541 case MCE_ERROR_TYPE_UNKNOWN:
542 err_type = "Unknown";
543 subtype = "";
544 break;
545 }
546
547 dar_str[0] = pa_str[0] = '\0';
548 if (ea && evt->srr0 != ea) {
549 /* Load/Store address */
550 n = sprintf(dar_str, "DAR: %016llx ", ea);
551 if (pa)
552 sprintf(dar_str + n, "paddr: %016llx ", pa);
553 } else if (pa) {
554 sprintf(pa_str, " paddr: %016llx", pa);
555 }
556
557 printk("%sMCE: CPU%d: machine check (%s) %s %s %s %s[%s]\n",
558 level, evt->cpu, sevstr, in_guest ? "Guest" : "Host",
559 err_type, subtype, dar_str,
560 evt->disposition == MCE_DISPOSITION_RECOVERED ?
561 "Recovered" : "Not recovered");
562
563 if (in_guest || user_mode) {
564 printk("%sMCE: CPU%d: PID: %d Comm: %s %sNIP: [%016llx]%s\n",
565 level, evt->cpu, current->pid, current->comm,
566 in_guest ? "Guest " : "", evt->srr0, pa_str);
567 } else {
568 printk("%sMCE: CPU%d: NIP: [%016llx] %pS%s\n",
569 level, evt->cpu, evt->srr0, (void *)evt->srr0, pa_str);
570 }
571
572 printk("%sMCE: CPU%d: Initiator %s\n", level, evt->cpu, initiator);
573
574 subtype = evt->error_class < ARRAY_SIZE(mc_error_class) ?
575 mc_error_class[evt->error_class] : "Unknown";
576 printk("%sMCE: CPU%d: %s\n", level, evt->cpu, subtype);
577
578#ifdef CONFIG_PPC_BOOK3S_64
579 /* Display faulty slb contents for SLB errors. */
580 if (evt->error_type == MCE_ERROR_TYPE_SLB)
581 slb_dump_contents(local_paca->mce_faulty_slbs);
582#endif
583}
584EXPORT_SYMBOL_GPL(machine_check_print_event_info);
585
586/*
587 * This function is called in real mode. Strictly no printk's please.
588 *
589 * regs->nip and regs->msr contains srr0 and ssr1.
590 */
591long notrace machine_check_early(struct pt_regs *regs)
592{
593 long handled = 0;
594 bool nested = in_nmi();
595 u8 ftrace_enabled = this_cpu_get_ftrace_enabled();
596
597 this_cpu_set_ftrace_enabled(0);
598
599 if (!nested)
600 nmi_enter();
601
602 hv_nmi_check_nonrecoverable(regs);
603
604 /*
605 * See if platform is capable of handling machine check.
606 */
607 if (ppc_md.machine_check_early)
608 handled = ppc_md.machine_check_early(regs);
609
610 if (!nested)
611 nmi_exit();
612
613 this_cpu_set_ftrace_enabled(ftrace_enabled);
614
615 return handled;
616}
617
618/* Possible meanings for HMER_DEBUG_TRIG bit being set on POWER9 */
619static enum {
620 DTRIG_UNKNOWN,
621 DTRIG_VECTOR_CI, /* need to emulate vector CI load instr */
622 DTRIG_SUSPEND_ESCAPE, /* need to escape from TM suspend mode */
623} hmer_debug_trig_function;
624
625static int init_debug_trig_function(void)
626{
627 int pvr;
628 struct device_node *cpun;
629 struct property *prop = NULL;
630 const char *str;
631
632 /* First look in the device tree */
633 preempt_disable();
634 cpun = of_get_cpu_node(smp_processor_id(), NULL);
635 if (cpun) {
636 of_property_for_each_string(cpun, "ibm,hmi-special-triggers",
637 prop, str) {
638 if (strcmp(str, "bit17-vector-ci-load") == 0)
639 hmer_debug_trig_function = DTRIG_VECTOR_CI;
640 else if (strcmp(str, "bit17-tm-suspend-escape") == 0)
641 hmer_debug_trig_function = DTRIG_SUSPEND_ESCAPE;
642 }
643 of_node_put(cpun);
644 }
645 preempt_enable();
646
647 /* If we found the property, don't look at PVR */
648 if (prop)
649 goto out;
650
651 pvr = mfspr(SPRN_PVR);
652 /* Check for POWER9 Nimbus (scale-out) */
653 if ((PVR_VER(pvr) == PVR_POWER9) && (pvr & 0xe000) == 0) {
654 /* DD2.2 and later */
655 if ((pvr & 0xfff) >= 0x202)
656 hmer_debug_trig_function = DTRIG_SUSPEND_ESCAPE;
657 /* DD2.0 and DD2.1 - used for vector CI load emulation */
658 else if ((pvr & 0xfff) >= 0x200)
659 hmer_debug_trig_function = DTRIG_VECTOR_CI;
660 }
661
662 out:
663 switch (hmer_debug_trig_function) {
664 case DTRIG_VECTOR_CI:
665 pr_debug("HMI debug trigger used for vector CI load\n");
666 break;
667 case DTRIG_SUSPEND_ESCAPE:
668 pr_debug("HMI debug trigger used for TM suspend escape\n");
669 break;
670 default:
671 break;
672 }
673 return 0;
674}
675__initcall(init_debug_trig_function);
676
677/*
678 * Handle HMIs that occur as a result of a debug trigger.
679 * Return values:
680 * -1 means this is not a HMI cause that we know about
681 * 0 means no further handling is required
682 * 1 means further handling is required
683 */
684long hmi_handle_debugtrig(struct pt_regs *regs)
685{
686 unsigned long hmer = mfspr(SPRN_HMER);
687 long ret = 0;
688
689 /* HMER_DEBUG_TRIG bit is used for various workarounds on P9 */
690 if (!((hmer & HMER_DEBUG_TRIG)
691 && hmer_debug_trig_function != DTRIG_UNKNOWN))
692 return -1;
693
694 hmer &= ~HMER_DEBUG_TRIG;
695 /* HMER is a write-AND register */
696 mtspr(SPRN_HMER, ~HMER_DEBUG_TRIG);
697
698 switch (hmer_debug_trig_function) {
699 case DTRIG_VECTOR_CI:
700 /*
701 * Now to avoid problems with soft-disable we
702 * only do the emulation if we are coming from
703 * host user space
704 */
705 if (regs && user_mode(regs))
706 ret = local_paca->hmi_p9_special_emu = 1;
707
708 break;
709
710 default:
711 break;
712 }
713
714 /*
715 * See if any other HMI causes remain to be handled
716 */
717 if (hmer & mfspr(SPRN_HMEER))
718 return -1;
719
720 return ret;
721}
722
723/*
724 * Return values:
725 */
726long hmi_exception_realmode(struct pt_regs *regs)
727{
728 int ret;
729
730 local_paca->hmi_irqs++;
731
732 ret = hmi_handle_debugtrig(regs);
733 if (ret >= 0)
734 return ret;
735
736 wait_for_subcore_guest_exit();
737
738 if (ppc_md.hmi_exception_early)
739 ppc_md.hmi_exception_early(regs);
740
741 wait_for_tb_resync();
742
743 return 1;
744}