1 // SPDX-License-Identifier: GPL-2.0
2 // Copyright (C) 2017 Arm Ltd.
3 #define pr_fmt(fmt) "sdei: " fmt
4
5 #include <acpi/ghes.h>
6 #include <linux/acpi.h>
7 #include <linux/arm_sdei.h>
8 #include <linux/arm-smccc.h>
9 #include <linux/atomic.h>
10 #include <linux/bitops.h>
11 #include <linux/compiler.h>
12 #include <linux/cpuhotplug.h>
13 #include <linux/cpu.h>
14 #include <linux/cpu_pm.h>
15 #include <linux/errno.h>
16 #include <linux/hardirq.h>
17 #include <linux/kernel.h>
18 #include <linux/kprobes.h>
19 #include <linux/kvm_host.h>
20 #include <linux/list.h>
21 #include <linux/mutex.h>
22 #include <linux/notifier.h>
23 #include <linux/of.h>
24 #include <linux/of_platform.h>
25 #include <linux/percpu.h>
26 #include <linux/platform_device.h>
27 #include <linux/pm.h>
28 #include <linux/ptrace.h>
29 #include <linux/preempt.h>
30 #include <linux/reboot.h>
31 #include <linux/slab.h>
32 #include <linux/smp.h>
33 #include <linux/spinlock.h>
34
35 /*
36 * The call to use to reach the firmware.
37 */
38 static asmlinkage void (*sdei_firmware_call)(unsigned long function_id,
39 unsigned long arg0, unsigned long arg1,
40 unsigned long arg2, unsigned long arg3,
41 unsigned long arg4, struct arm_smccc_res *res);
42
43 /* entry point from firmware to arch asm code */
44 static unsigned long sdei_entry_point;
45
46 static int sdei_hp_state;
47
48 struct sdei_event {
49 /* These three are protected by the sdei_list_lock */
50 struct list_head list;
51 bool reregister;
52 bool reenable;
53
54 u32 event_num;
55 u8 type;
56 u8 priority;
57
58 /* This pointer is handed to firmware as the event argument. */
59 union {
60 /* Shared events */
61 struct sdei_registered_event *registered;
62
63 /* CPU private events */
64 struct sdei_registered_event __percpu *private_registered;
65 };
66 };
67
68 /* Take the mutex for any API call or modification. Take the mutex first. */
69 static DEFINE_MUTEX(sdei_events_lock);
70
71 /* and then hold this when modifying the list */
72 static DEFINE_SPINLOCK(sdei_list_lock);
73 static LIST_HEAD(sdei_list);
74
75 /* Private events are registered/enabled via IPI passing one of these */
76 struct sdei_crosscall_args {
77 struct sdei_event *event;
78 atomic_t errors;
79 int first_error;
80 };
81
82 #define CROSSCALL_INIT(arg, event) \
83 do { \
84 arg.event = event; \
85 arg.first_error = 0; \
86 atomic_set(&arg.errors, 0); \
87 } while (0)
88
sdei_do_local_call(smp_call_func_t fn,struct sdei_event * event)89 static inline int sdei_do_local_call(smp_call_func_t fn,
90 struct sdei_event *event)
91 {
92 struct sdei_crosscall_args arg;
93
94 CROSSCALL_INIT(arg, event);
95 fn(&arg);
96
97 return arg.first_error;
98 }
99
sdei_do_cross_call(smp_call_func_t fn,struct sdei_event * event)100 static inline int sdei_do_cross_call(smp_call_func_t fn,
101 struct sdei_event *event)
102 {
103 struct sdei_crosscall_args arg;
104
105 CROSSCALL_INIT(arg, event);
106 on_each_cpu(fn, &arg, true);
107
108 return arg.first_error;
109 }
110
111 static inline void
sdei_cross_call_return(struct sdei_crosscall_args * arg,int err)112 sdei_cross_call_return(struct sdei_crosscall_args *arg, int err)
113 {
114 if (err && (atomic_inc_return(&arg->errors) == 1))
115 arg->first_error = err;
116 }
117
sdei_to_linux_errno(unsigned long sdei_err)118 static int sdei_to_linux_errno(unsigned long sdei_err)
119 {
120 switch (sdei_err) {
121 case SDEI_NOT_SUPPORTED:
122 return -EOPNOTSUPP;
123 case SDEI_INVALID_PARAMETERS:
124 return -EINVAL;
125 case SDEI_DENIED:
126 return -EPERM;
127 case SDEI_PENDING:
128 return -EINPROGRESS;
129 case SDEI_OUT_OF_RESOURCE:
130 return -ENOMEM;
131 }
132
133 return 0;
134 }
135
invoke_sdei_fn(unsigned long function_id,unsigned long arg0,unsigned long arg1,unsigned long arg2,unsigned long arg3,unsigned long arg4,u64 * result)136 static int invoke_sdei_fn(unsigned long function_id, unsigned long arg0,
137 unsigned long arg1, unsigned long arg2,
138 unsigned long arg3, unsigned long arg4,
139 u64 *result)
140 {
141 int err;
142 struct arm_smccc_res res;
143
144 if (sdei_firmware_call) {
145 sdei_firmware_call(function_id, arg0, arg1, arg2, arg3, arg4,
146 &res);
147 err = sdei_to_linux_errno(res.a0);
148 } else {
149 /*
150 * !sdei_firmware_call means we failed to probe or called
151 * sdei_mark_interface_broken(). -EIO is not an error returned
152 * by sdei_to_linux_errno() and is used to suppress messages
153 * from this driver.
154 */
155 err = -EIO;
156 res.a0 = SDEI_NOT_SUPPORTED;
157 }
158
159 if (result)
160 *result = res.a0;
161
162 return err;
163 }
164 NOKPROBE_SYMBOL(invoke_sdei_fn);
165
sdei_event_find(u32 event_num)166 static struct sdei_event *sdei_event_find(u32 event_num)
167 {
168 struct sdei_event *e, *found = NULL;
169
170 lockdep_assert_held(&sdei_events_lock);
171
172 spin_lock(&sdei_list_lock);
173 list_for_each_entry(e, &sdei_list, list) {
174 if (e->event_num == event_num) {
175 found = e;
176 break;
177 }
178 }
179 spin_unlock(&sdei_list_lock);
180
181 return found;
182 }
183
sdei_api_event_context(u32 query,u64 * result)184 int sdei_api_event_context(u32 query, u64 *result)
185 {
186 return invoke_sdei_fn(SDEI_1_0_FN_SDEI_EVENT_CONTEXT, query, 0, 0, 0, 0,
187 result);
188 }
189 NOKPROBE_SYMBOL(sdei_api_event_context);
190
sdei_api_event_get_info(u32 event,u32 info,u64 * result)191 static int sdei_api_event_get_info(u32 event, u32 info, u64 *result)
192 {
193 return invoke_sdei_fn(SDEI_1_0_FN_SDEI_EVENT_GET_INFO, event, info, 0,
194 0, 0, result);
195 }
196
sdei_event_create(u32 event_num,sdei_event_callback * cb,void * cb_arg)197 static struct sdei_event *sdei_event_create(u32 event_num,
198 sdei_event_callback *cb,
199 void *cb_arg)
200 {
201 int err;
202 u64 result;
203 struct sdei_event *event;
204 struct sdei_registered_event *reg;
205
206 lockdep_assert_held(&sdei_events_lock);
207
208 event = kzalloc(sizeof(*event), GFP_KERNEL);
209 if (!event) {
210 err = -ENOMEM;
211 goto fail;
212 }
213
214 INIT_LIST_HEAD(&event->list);
215 event->event_num = event_num;
216
217 err = sdei_api_event_get_info(event_num, SDEI_EVENT_INFO_EV_PRIORITY,
218 &result);
219 if (err)
220 goto fail;
221 event->priority = result;
222
223 err = sdei_api_event_get_info(event_num, SDEI_EVENT_INFO_EV_TYPE,
224 &result);
225 if (err)
226 goto fail;
227 event->type = result;
228
229 if (event->type == SDEI_EVENT_TYPE_SHARED) {
230 reg = kzalloc(sizeof(*reg), GFP_KERNEL);
231 if (!reg) {
232 err = -ENOMEM;
233 goto fail;
234 }
235
236 reg->event_num = event->event_num;
237 reg->priority = event->priority;
238
239 reg->callback = cb;
240 reg->callback_arg = cb_arg;
241 event->registered = reg;
242 } else {
243 int cpu;
244 struct sdei_registered_event __percpu *regs;
245
246 regs = alloc_percpu(struct sdei_registered_event);
247 if (!regs) {
248 err = -ENOMEM;
249 goto fail;
250 }
251
252 for_each_possible_cpu(cpu) {
253 reg = per_cpu_ptr(regs, cpu);
254
255 reg->event_num = event->event_num;
256 reg->priority = event->priority;
257 reg->callback = cb;
258 reg->callback_arg = cb_arg;
259 }
260
261 event->private_registered = regs;
262 }
263
264 spin_lock(&sdei_list_lock);
265 list_add(&event->list, &sdei_list);
266 spin_unlock(&sdei_list_lock);
267
268 return event;
269
270 fail:
271 kfree(event);
272 return ERR_PTR(err);
273 }
274
sdei_event_destroy_llocked(struct sdei_event * event)275 static void sdei_event_destroy_llocked(struct sdei_event *event)
276 {
277 lockdep_assert_held(&sdei_events_lock);
278 lockdep_assert_held(&sdei_list_lock);
279
280 list_del(&event->list);
281
282 if (event->type == SDEI_EVENT_TYPE_SHARED)
283 kfree(event->registered);
284 else
285 free_percpu(event->private_registered);
286
287 kfree(event);
288 }
289
sdei_event_destroy(struct sdei_event * event)290 static void sdei_event_destroy(struct sdei_event *event)
291 {
292 spin_lock(&sdei_list_lock);
293 sdei_event_destroy_llocked(event);
294 spin_unlock(&sdei_list_lock);
295 }
296
sdei_api_get_version(u64 * version)297 static int sdei_api_get_version(u64 *version)
298 {
299 return invoke_sdei_fn(SDEI_1_0_FN_SDEI_VERSION, 0, 0, 0, 0, 0, version);
300 }
301
sdei_mask_local_cpu(void)302 int sdei_mask_local_cpu(void)
303 {
304 int err;
305
306 err = invoke_sdei_fn(SDEI_1_0_FN_SDEI_PE_MASK, 0, 0, 0, 0, 0, NULL);
307 if (err && err != -EIO) {
308 pr_warn_once("failed to mask CPU[%u]: %d\n",
309 smp_processor_id(), err);
310 return err;
311 }
312
313 return 0;
314 }
315
_ipi_mask_cpu(void * ignored)316 static void _ipi_mask_cpu(void *ignored)
317 {
318 WARN_ON_ONCE(preemptible());
319 sdei_mask_local_cpu();
320 }
321
sdei_unmask_local_cpu(void)322 int sdei_unmask_local_cpu(void)
323 {
324 int err;
325
326 err = invoke_sdei_fn(SDEI_1_0_FN_SDEI_PE_UNMASK, 0, 0, 0, 0, 0, NULL);
327 if (err && err != -EIO) {
328 pr_warn_once("failed to unmask CPU[%u]: %d\n",
329 smp_processor_id(), err);
330 return err;
331 }
332
333 return 0;
334 }
335
_ipi_unmask_cpu(void * ignored)336 static void _ipi_unmask_cpu(void *ignored)
337 {
338 WARN_ON_ONCE(preemptible());
339 sdei_unmask_local_cpu();
340 }
341
_ipi_private_reset(void * ignored)342 static void _ipi_private_reset(void *ignored)
343 {
344 int err;
345
346 WARN_ON_ONCE(preemptible());
347
348 err = invoke_sdei_fn(SDEI_1_0_FN_SDEI_PRIVATE_RESET, 0, 0, 0, 0, 0,
349 NULL);
350 if (err && err != -EIO)
351 pr_warn_once("failed to reset CPU[%u]: %d\n",
352 smp_processor_id(), err);
353 }
354
sdei_api_shared_reset(void)355 static int sdei_api_shared_reset(void)
356 {
357 return invoke_sdei_fn(SDEI_1_0_FN_SDEI_SHARED_RESET, 0, 0, 0, 0, 0,
358 NULL);
359 }
360
sdei_mark_interface_broken(void)361 static void sdei_mark_interface_broken(void)
362 {
363 pr_err("disabling SDEI firmware interface\n");
364 on_each_cpu(&_ipi_mask_cpu, NULL, true);
365 sdei_firmware_call = NULL;
366 }
367
sdei_platform_reset(void)368 static int sdei_platform_reset(void)
369 {
370 int err;
371
372 on_each_cpu(&_ipi_private_reset, NULL, true);
373 err = sdei_api_shared_reset();
374 if (err) {
375 pr_err("Failed to reset platform: %d\n", err);
376 sdei_mark_interface_broken();
377 }
378
379 return err;
380 }
381
sdei_api_event_enable(u32 event_num)382 static int sdei_api_event_enable(u32 event_num)
383 {
384 return invoke_sdei_fn(SDEI_1_0_FN_SDEI_EVENT_ENABLE, event_num, 0, 0, 0,
385 0, NULL);
386 }
387
388 /* Called directly by the hotplug callbacks */
_local_event_enable(void * data)389 static void _local_event_enable(void *data)
390 {
391 int err;
392 struct sdei_crosscall_args *arg = data;
393
394 err = sdei_api_event_enable(arg->event->event_num);
395
396 sdei_cross_call_return(arg, err);
397 }
398
sdei_event_enable(u32 event_num)399 int sdei_event_enable(u32 event_num)
400 {
401 int err = -EINVAL;
402 struct sdei_event *event;
403
404 mutex_lock(&sdei_events_lock);
405 event = sdei_event_find(event_num);
406 if (!event) {
407 mutex_unlock(&sdei_events_lock);
408 return -ENOENT;
409 }
410
411
412 cpus_read_lock();
413 if (event->type == SDEI_EVENT_TYPE_SHARED)
414 err = sdei_api_event_enable(event->event_num);
415 else
416 err = sdei_do_cross_call(_local_event_enable, event);
417
418 if (!err) {
419 spin_lock(&sdei_list_lock);
420 event->reenable = true;
421 spin_unlock(&sdei_list_lock);
422 }
423 cpus_read_unlock();
424 mutex_unlock(&sdei_events_lock);
425
426 return err;
427 }
428
sdei_api_event_disable(u32 event_num)429 static int sdei_api_event_disable(u32 event_num)
430 {
431 return invoke_sdei_fn(SDEI_1_0_FN_SDEI_EVENT_DISABLE, event_num, 0, 0,
432 0, 0, NULL);
433 }
434
_ipi_event_disable(void * data)435 static void _ipi_event_disable(void *data)
436 {
437 int err;
438 struct sdei_crosscall_args *arg = data;
439
440 err = sdei_api_event_disable(arg->event->event_num);
441
442 sdei_cross_call_return(arg, err);
443 }
444
sdei_event_disable(u32 event_num)445 int sdei_event_disable(u32 event_num)
446 {
447 int err = -EINVAL;
448 struct sdei_event *event;
449
450 mutex_lock(&sdei_events_lock);
451 event = sdei_event_find(event_num);
452 if (!event) {
453 mutex_unlock(&sdei_events_lock);
454 return -ENOENT;
455 }
456
457 spin_lock(&sdei_list_lock);
458 event->reenable = false;
459 spin_unlock(&sdei_list_lock);
460
461 if (event->type == SDEI_EVENT_TYPE_SHARED)
462 err = sdei_api_event_disable(event->event_num);
463 else
464 err = sdei_do_cross_call(_ipi_event_disable, event);
465 mutex_unlock(&sdei_events_lock);
466
467 return err;
468 }
469
sdei_api_event_unregister(u32 event_num)470 static int sdei_api_event_unregister(u32 event_num)
471 {
472 return invoke_sdei_fn(SDEI_1_0_FN_SDEI_EVENT_UNREGISTER, event_num, 0,
473 0, 0, 0, NULL);
474 }
475
476 /* Called directly by the hotplug callbacks */
_local_event_unregister(void * data)477 static void _local_event_unregister(void *data)
478 {
479 int err;
480 struct sdei_crosscall_args *arg = data;
481
482 err = sdei_api_event_unregister(arg->event->event_num);
483
484 sdei_cross_call_return(arg, err);
485 }
486
sdei_event_unregister(u32 event_num)487 int sdei_event_unregister(u32 event_num)
488 {
489 int err;
490 struct sdei_event *event;
491
492 WARN_ON(in_nmi());
493
494 mutex_lock(&sdei_events_lock);
495 event = sdei_event_find(event_num);
496 if (!event) {
497 pr_warn("Event %u not registered\n", event_num);
498 err = -ENOENT;
499 goto unlock;
500 }
501
502 spin_lock(&sdei_list_lock);
503 event->reregister = false;
504 event->reenable = false;
505 spin_unlock(&sdei_list_lock);
506
507 if (event->type == SDEI_EVENT_TYPE_SHARED)
508 err = sdei_api_event_unregister(event->event_num);
509 else
510 err = sdei_do_cross_call(_local_event_unregister, event);
511
512 if (err)
513 goto unlock;
514
515 sdei_event_destroy(event);
516 unlock:
517 mutex_unlock(&sdei_events_lock);
518
519 return err;
520 }
521
522 /*
523 * unregister events, but don't destroy them as they are re-registered by
524 * sdei_reregister_shared().
525 */
sdei_unregister_shared(void)526 static int sdei_unregister_shared(void)
527 {
528 int err = 0;
529 struct sdei_event *event;
530
531 mutex_lock(&sdei_events_lock);
532 spin_lock(&sdei_list_lock);
533 list_for_each_entry(event, &sdei_list, list) {
534 if (event->type != SDEI_EVENT_TYPE_SHARED)
535 continue;
536
537 err = sdei_api_event_unregister(event->event_num);
538 if (err)
539 break;
540 }
541 spin_unlock(&sdei_list_lock);
542 mutex_unlock(&sdei_events_lock);
543
544 return err;
545 }
546
sdei_api_event_register(u32 event_num,unsigned long entry_point,void * arg,u64 flags,u64 affinity)547 static int sdei_api_event_register(u32 event_num, unsigned long entry_point,
548 void *arg, u64 flags, u64 affinity)
549 {
550 return invoke_sdei_fn(SDEI_1_0_FN_SDEI_EVENT_REGISTER, event_num,
551 (unsigned long)entry_point, (unsigned long)arg,
552 flags, affinity, NULL);
553 }
554
555 /* Called directly by the hotplug callbacks */
_local_event_register(void * data)556 static void _local_event_register(void *data)
557 {
558 int err;
559 struct sdei_registered_event *reg;
560 struct sdei_crosscall_args *arg = data;
561
562 reg = per_cpu_ptr(arg->event->private_registered, smp_processor_id());
563 err = sdei_api_event_register(arg->event->event_num, sdei_entry_point,
564 reg, 0, 0);
565
566 sdei_cross_call_return(arg, err);
567 }
568
sdei_event_register(u32 event_num,sdei_event_callback * cb,void * arg)569 int sdei_event_register(u32 event_num, sdei_event_callback *cb, void *arg)
570 {
571 int err;
572 struct sdei_event *event;
573
574 WARN_ON(in_nmi());
575
576 mutex_lock(&sdei_events_lock);
577 if (sdei_event_find(event_num)) {
578 pr_warn("Event %u already registered\n", event_num);
579 err = -EBUSY;
580 goto unlock;
581 }
582
583 event = sdei_event_create(event_num, cb, arg);
584 if (IS_ERR(event)) {
585 err = PTR_ERR(event);
586 pr_warn("Failed to create event %u: %d\n", event_num, err);
587 goto unlock;
588 }
589
590 cpus_read_lock();
591 if (event->type == SDEI_EVENT_TYPE_SHARED) {
592 err = sdei_api_event_register(event->event_num,
593 sdei_entry_point,
594 event->registered,
595 SDEI_EVENT_REGISTER_RM_ANY, 0);
596 } else {
597 err = sdei_do_cross_call(_local_event_register, event);
598 if (err)
599 sdei_do_cross_call(_local_event_unregister, event);
600 }
601
602 if (err) {
603 sdei_event_destroy(event);
604 pr_warn("Failed to register event %u: %d\n", event_num, err);
605 goto cpu_unlock;
606 }
607
608 spin_lock(&sdei_list_lock);
609 event->reregister = true;
610 spin_unlock(&sdei_list_lock);
611 cpu_unlock:
612 cpus_read_unlock();
613 unlock:
614 mutex_unlock(&sdei_events_lock);
615 return err;
616 }
617
sdei_reregister_shared(void)618 static int sdei_reregister_shared(void)
619 {
620 int err = 0;
621 struct sdei_event *event;
622
623 mutex_lock(&sdei_events_lock);
624 spin_lock(&sdei_list_lock);
625 list_for_each_entry(event, &sdei_list, list) {
626 if (event->type != SDEI_EVENT_TYPE_SHARED)
627 continue;
628
629 if (event->reregister) {
630 err = sdei_api_event_register(event->event_num,
631 sdei_entry_point, event->registered,
632 SDEI_EVENT_REGISTER_RM_ANY, 0);
633 if (err) {
634 pr_err("Failed to re-register event %u\n",
635 event->event_num);
636 sdei_event_destroy_llocked(event);
637 break;
638 }
639 }
640
641 if (event->reenable) {
642 err = sdei_api_event_enable(event->event_num);
643 if (err) {
644 pr_err("Failed to re-enable event %u\n",
645 event->event_num);
646 break;
647 }
648 }
649 }
650 spin_unlock(&sdei_list_lock);
651 mutex_unlock(&sdei_events_lock);
652
653 return err;
654 }
655
sdei_cpuhp_down(unsigned int cpu)656 static int sdei_cpuhp_down(unsigned int cpu)
657 {
658 struct sdei_event *event;
659 int err;
660
661 /* un-register private events */
662 spin_lock(&sdei_list_lock);
663 list_for_each_entry(event, &sdei_list, list) {
664 if (event->type == SDEI_EVENT_TYPE_SHARED)
665 continue;
666
667 err = sdei_do_local_call(_local_event_unregister, event);
668 if (err) {
669 pr_err("Failed to unregister event %u: %d\n",
670 event->event_num, err);
671 }
672 }
673 spin_unlock(&sdei_list_lock);
674
675 return sdei_mask_local_cpu();
676 }
677
sdei_cpuhp_up(unsigned int cpu)678 static int sdei_cpuhp_up(unsigned int cpu)
679 {
680 struct sdei_event *event;
681 int err;
682
683 /* re-register/enable private events */
684 spin_lock(&sdei_list_lock);
685 list_for_each_entry(event, &sdei_list, list) {
686 if (event->type == SDEI_EVENT_TYPE_SHARED)
687 continue;
688
689 if (event->reregister) {
690 err = sdei_do_local_call(_local_event_register, event);
691 if (err) {
692 pr_err("Failed to re-register event %u: %d\n",
693 event->event_num, err);
694 }
695 }
696
697 if (event->reenable) {
698 err = sdei_do_local_call(_local_event_enable, event);
699 if (err) {
700 pr_err("Failed to re-enable event %u: %d\n",
701 event->event_num, err);
702 }
703 }
704 }
705 spin_unlock(&sdei_list_lock);
706
707 return sdei_unmask_local_cpu();
708 }
709
710 /* When entering idle, mask/unmask events for this cpu */
sdei_pm_notifier(struct notifier_block * nb,unsigned long action,void * data)711 static int sdei_pm_notifier(struct notifier_block *nb, unsigned long action,
712 void *data)
713 {
714 int rv;
715
716 WARN_ON_ONCE(preemptible());
717
718 switch (action) {
719 case CPU_PM_ENTER:
720 rv = sdei_mask_local_cpu();
721 break;
722 case CPU_PM_EXIT:
723 case CPU_PM_ENTER_FAILED:
724 rv = sdei_unmask_local_cpu();
725 break;
726 default:
727 return NOTIFY_DONE;
728 }
729
730 if (rv)
731 return notifier_from_errno(rv);
732
733 return NOTIFY_OK;
734 }
735
736 static struct notifier_block sdei_pm_nb = {
737 .notifier_call = sdei_pm_notifier,
738 };
739
sdei_device_suspend(struct device * dev)740 static int sdei_device_suspend(struct device *dev)
741 {
742 on_each_cpu(_ipi_mask_cpu, NULL, true);
743
744 return 0;
745 }
746
sdei_device_resume(struct device * dev)747 static int sdei_device_resume(struct device *dev)
748 {
749 on_each_cpu(_ipi_unmask_cpu, NULL, true);
750
751 return 0;
752 }
753
754 /*
755 * We need all events to be reregistered when we resume from hibernate.
756 *
757 * The sequence is freeze->thaw. Reboot. freeze->restore. We unregister
758 * events during freeze, then re-register and re-enable them during thaw
759 * and restore.
760 */
sdei_device_freeze(struct device * dev)761 static int sdei_device_freeze(struct device *dev)
762 {
763 int err;
764
765 /* unregister private events */
766 cpuhp_remove_state(sdei_hp_state);
767
768 err = sdei_unregister_shared();
769 if (err)
770 return err;
771
772 return 0;
773 }
774
sdei_device_thaw(struct device * dev)775 static int sdei_device_thaw(struct device *dev)
776 {
777 int err;
778
779 /* re-register shared events */
780 err = sdei_reregister_shared();
781 if (err) {
782 pr_warn("Failed to re-register shared events...\n");
783 sdei_mark_interface_broken();
784 return err;
785 }
786
787 err = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "SDEI",
788 &sdei_cpuhp_up, &sdei_cpuhp_down);
789 if (err < 0) {
790 pr_warn("Failed to re-register CPU hotplug notifier...\n");
791 return err;
792 }
793
794 sdei_hp_state = err;
795 return 0;
796 }
797
sdei_device_restore(struct device * dev)798 static int sdei_device_restore(struct device *dev)
799 {
800 int err;
801
802 err = sdei_platform_reset();
803 if (err)
804 return err;
805
806 return sdei_device_thaw(dev);
807 }
808
809 static const struct dev_pm_ops sdei_pm_ops = {
810 .suspend = sdei_device_suspend,
811 .resume = sdei_device_resume,
812 .freeze = sdei_device_freeze,
813 .thaw = sdei_device_thaw,
814 .restore = sdei_device_restore,
815 };
816
817 /*
818 * Mask all CPUs and unregister all events on panic, reboot or kexec.
819 */
sdei_reboot_notifier(struct notifier_block * nb,unsigned long action,void * data)820 static int sdei_reboot_notifier(struct notifier_block *nb, unsigned long action,
821 void *data)
822 {
823 /*
824 * We are going to reset the interface, after this there is no point
825 * doing work when we take CPUs offline.
826 */
827 cpuhp_remove_state(sdei_hp_state);
828
829 sdei_platform_reset();
830
831 return NOTIFY_OK;
832 }
833
834 static struct notifier_block sdei_reboot_nb = {
835 .notifier_call = sdei_reboot_notifier,
836 };
837
sdei_smccc_smc(unsigned long function_id,unsigned long arg0,unsigned long arg1,unsigned long arg2,unsigned long arg3,unsigned long arg4,struct arm_smccc_res * res)838 static void sdei_smccc_smc(unsigned long function_id,
839 unsigned long arg0, unsigned long arg1,
840 unsigned long arg2, unsigned long arg3,
841 unsigned long arg4, struct arm_smccc_res *res)
842 {
843 arm_smccc_smc(function_id, arg0, arg1, arg2, arg3, arg4, 0, 0, res);
844 }
845 NOKPROBE_SYMBOL(sdei_smccc_smc);
846
sdei_smccc_hvc(unsigned long function_id,unsigned long arg0,unsigned long arg1,unsigned long arg2,unsigned long arg3,unsigned long arg4,struct arm_smccc_res * res)847 static void sdei_smccc_hvc(unsigned long function_id,
848 unsigned long arg0, unsigned long arg1,
849 unsigned long arg2, unsigned long arg3,
850 unsigned long arg4, struct arm_smccc_res *res)
851 {
852 arm_smccc_hvc(function_id, arg0, arg1, arg2, arg3, arg4, 0, 0, res);
853 }
854 NOKPROBE_SYMBOL(sdei_smccc_hvc);
855
sdei_register_ghes(struct ghes * ghes,sdei_event_callback * normal_cb,sdei_event_callback * critical_cb)856 int sdei_register_ghes(struct ghes *ghes, sdei_event_callback *normal_cb,
857 sdei_event_callback *critical_cb)
858 {
859 int err;
860 u64 result;
861 u32 event_num;
862 sdei_event_callback *cb;
863
864 if (!IS_ENABLED(CONFIG_ACPI_APEI_GHES))
865 return -EOPNOTSUPP;
866
867 event_num = ghes->generic->notify.vector;
868 if (event_num == 0) {
869 /*
870 * Event 0 is reserved by the specification for
871 * SDEI_EVENT_SIGNAL.
872 */
873 return -EINVAL;
874 }
875
876 err = sdei_api_event_get_info(event_num, SDEI_EVENT_INFO_EV_PRIORITY,
877 &result);
878 if (err)
879 return err;
880
881 if (result == SDEI_EVENT_PRIORITY_CRITICAL)
882 cb = critical_cb;
883 else
884 cb = normal_cb;
885
886 err = sdei_event_register(event_num, cb, ghes);
887 if (!err)
888 err = sdei_event_enable(event_num);
889
890 return err;
891 }
892
sdei_unregister_ghes(struct ghes * ghes)893 int sdei_unregister_ghes(struct ghes *ghes)
894 {
895 int i;
896 int err;
897 u32 event_num = ghes->generic->notify.vector;
898
899 might_sleep();
900
901 if (!IS_ENABLED(CONFIG_ACPI_APEI_GHES))
902 return -EOPNOTSUPP;
903
904 /*
905 * The event may be running on another CPU. Disable it
906 * to stop new events, then try to unregister a few times.
907 */
908 err = sdei_event_disable(event_num);
909 if (err)
910 return err;
911
912 for (i = 0; i < 3; i++) {
913 err = sdei_event_unregister(event_num);
914 if (err != -EINPROGRESS)
915 break;
916
917 schedule();
918 }
919
920 return err;
921 }
922
sdei_get_conduit(struct platform_device * pdev)923 static int sdei_get_conduit(struct platform_device *pdev)
924 {
925 const char *method;
926 struct device_node *np = pdev->dev.of_node;
927
928 sdei_firmware_call = NULL;
929 if (np) {
930 if (of_property_read_string(np, "method", &method)) {
931 pr_warn("missing \"method\" property\n");
932 return SMCCC_CONDUIT_NONE;
933 }
934
935 if (!strcmp("hvc", method)) {
936 sdei_firmware_call = &sdei_smccc_hvc;
937 return SMCCC_CONDUIT_HVC;
938 } else if (!strcmp("smc", method)) {
939 sdei_firmware_call = &sdei_smccc_smc;
940 return SMCCC_CONDUIT_SMC;
941 }
942
943 pr_warn("invalid \"method\" property: %s\n", method);
944 } else if (!acpi_disabled) {
945 if (acpi_psci_use_hvc()) {
946 sdei_firmware_call = &sdei_smccc_hvc;
947 return SMCCC_CONDUIT_HVC;
948 } else {
949 sdei_firmware_call = &sdei_smccc_smc;
950 return SMCCC_CONDUIT_SMC;
951 }
952 }
953
954 return SMCCC_CONDUIT_NONE;
955 }
956
sdei_probe(struct platform_device * pdev)957 static int sdei_probe(struct platform_device *pdev)
958 {
959 int err;
960 u64 ver = 0;
961 int conduit;
962
963 conduit = sdei_get_conduit(pdev);
964 if (!sdei_firmware_call)
965 return 0;
966
967 err = sdei_api_get_version(&ver);
968 if (err) {
969 pr_err("Failed to get SDEI version: %d\n", err);
970 sdei_mark_interface_broken();
971 return err;
972 }
973
974 pr_info("SDEIv%d.%d (0x%x) detected in firmware.\n",
975 (int)SDEI_VERSION_MAJOR(ver), (int)SDEI_VERSION_MINOR(ver),
976 (int)SDEI_VERSION_VENDOR(ver));
977
978 if (SDEI_VERSION_MAJOR(ver) != 1) {
979 pr_warn("Conflicting SDEI version detected.\n");
980 sdei_mark_interface_broken();
981 return -EINVAL;
982 }
983
984 err = sdei_platform_reset();
985 if (err)
986 return err;
987
988 sdei_entry_point = sdei_arch_get_entry_point(conduit);
989 if (!sdei_entry_point) {
990 /* Not supported due to hardware or boot configuration */
991 sdei_mark_interface_broken();
992 return 0;
993 }
994
995 err = cpu_pm_register_notifier(&sdei_pm_nb);
996 if (err) {
997 pr_warn("Failed to register CPU PM notifier...\n");
998 goto error;
999 }
1000
1001 err = register_reboot_notifier(&sdei_reboot_nb);
1002 if (err) {
1003 pr_warn("Failed to register reboot notifier...\n");
1004 goto remove_cpupm;
1005 }
1006
1007 err = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "SDEI",
1008 &sdei_cpuhp_up, &sdei_cpuhp_down);
1009 if (err < 0) {
1010 pr_warn("Failed to register CPU hotplug notifier...\n");
1011 goto remove_reboot;
1012 }
1013
1014 sdei_hp_state = err;
1015
1016 return 0;
1017
1018 remove_reboot:
1019 unregister_reboot_notifier(&sdei_reboot_nb);
1020
1021 remove_cpupm:
1022 cpu_pm_unregister_notifier(&sdei_pm_nb);
1023
1024 error:
1025 sdei_mark_interface_broken();
1026 return err;
1027 }
1028
1029 static const struct of_device_id sdei_of_match[] = {
1030 { .compatible = "arm,sdei-1.0" },
1031 {}
1032 };
1033
1034 static struct platform_driver sdei_driver = {
1035 .driver = {
1036 .name = "sdei",
1037 .pm = &sdei_pm_ops,
1038 .of_match_table = sdei_of_match,
1039 },
1040 .probe = sdei_probe,
1041 };
1042
sdei_present_acpi(void)1043 static bool __init sdei_present_acpi(void)
1044 {
1045 acpi_status status;
1046 struct acpi_table_header *sdei_table_header;
1047
1048 if (acpi_disabled)
1049 return false;
1050
1051 status = acpi_get_table(ACPI_SIG_SDEI, 0, &sdei_table_header);
1052 if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
1053 const char *msg = acpi_format_exception(status);
1054
1055 pr_info("Failed to get ACPI:SDEI table, %s\n", msg);
1056 }
1057 if (ACPI_FAILURE(status))
1058 return false;
1059
1060 acpi_put_table(sdei_table_header);
1061
1062 return true;
1063 }
1064
sdei_init(void)1065 void __init sdei_init(void)
1066 {
1067 struct platform_device *pdev;
1068 int ret;
1069
1070 ret = platform_driver_register(&sdei_driver);
1071 if (ret || !sdei_present_acpi())
1072 return;
1073
1074 pdev = platform_device_register_simple(sdei_driver.driver.name,
1075 0, NULL, 0);
1076 if (IS_ERR(pdev)) {
1077 ret = PTR_ERR(pdev);
1078 platform_driver_unregister(&sdei_driver);
1079 pr_info("Failed to register ACPI:SDEI platform device %d\n",
1080 ret);
1081 }
1082 }
1083
sdei_event_handler(struct pt_regs * regs,struct sdei_registered_event * arg)1084 int sdei_event_handler(struct pt_regs *regs,
1085 struct sdei_registered_event *arg)
1086 {
1087 int err;
1088 u32 event_num = arg->event_num;
1089
1090 err = arg->callback(event_num, regs, arg->callback_arg);
1091 if (err)
1092 pr_err_ratelimited("event %u on CPU %u failed with error: %d\n",
1093 event_num, smp_processor_id(), err);
1094
1095 return err;
1096 }
1097 NOKPROBE_SYMBOL(sdei_event_handler);
1098
sdei_handler_abort(void)1099 void sdei_handler_abort(void)
1100 {
1101 /*
1102 * If the crash happened in an SDEI event handler then we need to
1103 * finish the handler with the firmware so that we can have working
1104 * interrupts in the crash kernel.
1105 */
1106 if (__this_cpu_read(sdei_active_critical_event)) {
1107 pr_warn("still in SDEI critical event context, attempting to finish handler.\n");
1108 __sdei_handler_abort();
1109 __this_cpu_write(sdei_active_critical_event, NULL);
1110 }
1111 if (__this_cpu_read(sdei_active_normal_event)) {
1112 pr_warn("still in SDEI normal event context, attempting to finish handler.\n");
1113 __sdei_handler_abort();
1114 __this_cpu_write(sdei_active_normal_event, NULL);
1115 }
1116 }
1117