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Linux 4.19-rc7
[linux-2.6/btrfs-unstable.git] / drivers / firmware / arm_sdei.c
blob1ea71640fdc21dd6b8b96c93d1383babc6e89a33
1 // SPDX-License-Identifier: GPL-2.0
2 // Copyright (C) 2017 Arm Ltd.
3 #define pr_fmt(fmt) "sdei: " fmt
4
5 #include <linux/acpi.h>
6 #include <linux/arm_sdei.h>
7 #include <linux/arm-smccc.h>
8 #include <linux/atomic.h>
9 #include <linux/bitops.h>
10 #include <linux/compiler.h>
11 #include <linux/cpuhotplug.h>
12 #include <linux/cpu.h>
13 #include <linux/cpu_pm.h>
14 #include <linux/errno.h>
15 #include <linux/hardirq.h>
16 #include <linux/kernel.h>
17 #include <linux/kprobes.h>
18 #include <linux/kvm_host.h>
19 #include <linux/list.h>
20 #include <linux/mutex.h>
21 #include <linux/notifier.h>
22 #include <linux/of.h>
23 #include <linux/of_platform.h>
24 #include <linux/percpu.h>
25 #include <linux/platform_device.h>
26 #include <linux/pm.h>
27 #include <linux/ptrace.h>
28 #include <linux/preempt.h>
29 #include <linux/reboot.h>
30 #include <linux/slab.h>
31 #include <linux/smp.h>
32 #include <linux/spinlock.h>
33 #include <linux/uaccess.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 struct sdei_event {
47 /* These three are protected by the sdei_list_lock */
48 struct list_head list;
49 bool reregister;
50 bool reenable;
51
52 u32 event_num;
53 u8 type;
54 u8 priority;
55
56 /* This pointer is handed to firmware as the event argument. */
57 union {
58 /* Shared events */
59 struct sdei_registered_event *registered;
60
61 /* CPU private events */
62 struct sdei_registered_event __percpu *private_registered;
63 };
64 };
65
66 /* Take the mutex for any API call or modification. Take the mutex first. */
67 static DEFINE_MUTEX(sdei_events_lock);
68
69 /* and then hold this when modifying the list */
70 static DEFINE_SPINLOCK(sdei_list_lock);
71 static LIST_HEAD(sdei_list);
72
73 /* Private events are registered/enabled via IPI passing one of these */
74 struct sdei_crosscall_args {
75 struct sdei_event *event;
76 atomic_t errors;
77 int first_error;
78 };
79
80 #define CROSSCALL_INIT(arg, event) (arg.event = event, \
81 arg.first_error = 0, \
82 atomic_set(&arg.errors, 0))
83
84 static inline int sdei_do_cross_call(void *fn, struct sdei_event * event)
85 {
86 struct sdei_crosscall_args arg;
87
88 CROSSCALL_INIT(arg, event);
89 on_each_cpu(fn, &arg, true);
90
91 return arg.first_error;
92 }
93
94 static inline void
95 sdei_cross_call_return(struct sdei_crosscall_args *arg, int err)
96 {
97 if (err && (atomic_inc_return(&arg->errors) == 1))
98 arg->first_error = err;
99 }
100
101 static int sdei_to_linux_errno(unsigned long sdei_err)
102 {
103 switch (sdei_err) {
104 case SDEI_NOT_SUPPORTED:
105 return -EOPNOTSUPP;
106 case SDEI_INVALID_PARAMETERS:
107 return -EINVAL;
108 case SDEI_DENIED:
109 return -EPERM;
110 case SDEI_PENDING:
111 return -EINPROGRESS;
112 case SDEI_OUT_OF_RESOURCE:
113 return -ENOMEM;
114 }
115
116 /* Not an error value ... */
117 return sdei_err;
118 }
119
120 /*
121 * If x0 is any of these values, then the call failed, use sdei_to_linux_errno()
122 * to translate.
123 */
124 static int sdei_is_err(struct arm_smccc_res *res)
125 {
126 switch (res->a0) {
127 case SDEI_NOT_SUPPORTED:
128 case SDEI_INVALID_PARAMETERS:
129 case SDEI_DENIED:
130 case SDEI_PENDING:
131 case SDEI_OUT_OF_RESOURCE:
132 return true;
133 }
134
135 return false;
136 }
137
138 static int invoke_sdei_fn(unsigned long function_id, unsigned long arg0,
139 unsigned long arg1, unsigned long arg2,
140 unsigned long arg3, unsigned long arg4,
141 u64 *result)
142 {
143 int err = 0;
144 struct arm_smccc_res res;
145
146 if (sdei_firmware_call) {
147 sdei_firmware_call(function_id, arg0, arg1, arg2, arg3, arg4,
148 &res);
149 if (sdei_is_err(&res))
150 err = sdei_to_linux_errno(res.a0);
151 } else {
152 /*
153 * !sdei_firmware_call means we failed to probe or called
154 * sdei_mark_interface_broken(). -EIO is not an error returned
155 * by sdei_to_linux_errno() and is used to suppress messages
156 * from this driver.
157 */
158 err = -EIO;
159 res.a0 = SDEI_NOT_SUPPORTED;
160 }
161
162 if (result)
163 *result = res.a0;
164
165 return err;
166 }
167
168 static struct sdei_event *sdei_event_find(u32 event_num)
169 {
170 struct sdei_event *e, *found = NULL;
171
172 lockdep_assert_held(&sdei_events_lock);
173
174 spin_lock(&sdei_list_lock);
175 list_for_each_entry(e, &sdei_list, list) {
176 if (e->event_num == event_num) {
177 found = e;
178 break;
179 }
180 }
181 spin_unlock(&sdei_list_lock);
182
183 return found;
184 }
185
186 int sdei_api_event_context(u32 query, u64 *result)
187 {
188 return invoke_sdei_fn(SDEI_1_0_FN_SDEI_EVENT_CONTEXT, query, 0, 0, 0, 0,
189 result);
190 }
191 NOKPROBE_SYMBOL(sdei_api_event_context);
192
193 static int sdei_api_event_get_info(u32 event, u32 info, u64 *result)
194 {
195 return invoke_sdei_fn(SDEI_1_0_FN_SDEI_EVENT_GET_INFO, event, info, 0,
196 0, 0, result);
197 }
198
199 static struct sdei_event *sdei_event_create(u32 event_num,
200 sdei_event_callback *cb,
201 void *cb_arg)
202 {
203 int err;
204 u64 result;
205 struct sdei_event *event;
206 struct sdei_registered_event *reg;
207
208 lockdep_assert_held(&sdei_events_lock);
209
210 event = kzalloc(sizeof(*event), GFP_KERNEL);
211 if (!event)
212 return ERR_PTR(-ENOMEM);
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 kfree(event);
221 return ERR_PTR(err);
222 }
223 event->priority = result;
224
225 err = sdei_api_event_get_info(event_num, SDEI_EVENT_INFO_EV_TYPE,
226 &result);
227 if (err) {
228 kfree(event);
229 return ERR_PTR(err);
230 }
231 event->type = result;
232
233 if (event->type == SDEI_EVENT_TYPE_SHARED) {
234 reg = kzalloc(sizeof(*reg), GFP_KERNEL);
235 if (!reg) {
236 kfree(event);
237 return ERR_PTR(-ENOMEM);
238 }
239
240 reg->event_num = event_num;
241 reg->priority = event->priority;
242
243 reg->callback = cb;
244 reg->callback_arg = cb_arg;
245 event->registered = reg;
246 } else {
247 int cpu;
248 struct sdei_registered_event __percpu *regs;
249
250 regs = alloc_percpu(struct sdei_registered_event);
251 if (!regs) {
252 kfree(event);
253 return ERR_PTR(-ENOMEM);
254 }
255
256 for_each_possible_cpu(cpu) {
257 reg = per_cpu_ptr(regs, cpu);
258
259 reg->event_num = event->event_num;
260 reg->priority = event->priority;
261 reg->callback = cb;
262 reg->callback_arg = cb_arg;
263 }
264
265 event->private_registered = regs;
266 }
267
268 if (sdei_event_find(event_num)) {
269 kfree(event->registered);
270 kfree(event);
271 event = ERR_PTR(-EBUSY);
272 } else {
273 spin_lock(&sdei_list_lock);
274 list_add(&event->list, &sdei_list);
275 spin_unlock(&sdei_list_lock);
276 }
277
278 return event;
279 }
280
281 static void sdei_event_destroy(struct sdei_event *event)
282 {
283 lockdep_assert_held(&sdei_events_lock);
284
285 spin_lock(&sdei_list_lock);
286 list_del(&event->list);
287 spin_unlock(&sdei_list_lock);
288
289 if (event->type == SDEI_EVENT_TYPE_SHARED)
290 kfree(event->registered);
291 else
292 free_percpu(event->private_registered);
293
294 kfree(event);
295 }
296
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
302 int sdei_mask_local_cpu(void)
303 {
304 int err;
305
306 WARN_ON_ONCE(preemptible());
307
308 err = invoke_sdei_fn(SDEI_1_0_FN_SDEI_PE_MASK, 0, 0, 0, 0, 0, NULL);
309 if (err && err != -EIO) {
310 pr_warn_once("failed to mask CPU[%u]: %d\n",
311 smp_processor_id(), err);
312 return err;
313 }
314
315 return 0;
316 }
317
318 static void _ipi_mask_cpu(void *ignored)
319 {
320 sdei_mask_local_cpu();
321 }
322
323 int sdei_unmask_local_cpu(void)
324 {
325 int err;
326
327 WARN_ON_ONCE(preemptible());
328
329 err = invoke_sdei_fn(SDEI_1_0_FN_SDEI_PE_UNMASK, 0, 0, 0, 0, 0, NULL);
330 if (err && err != -EIO) {
331 pr_warn_once("failed to unmask CPU[%u]: %d\n",
332 smp_processor_id(), err);
333 return err;
334 }
335
336 return 0;
337 }
338
339 static void _ipi_unmask_cpu(void *ignored)
340 {
341 sdei_unmask_local_cpu();
342 }
343
344 static void _ipi_private_reset(void *ignored)
345 {
346 int err;
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
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
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
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
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 */
389 static void _local_event_enable(void *data)
390 {
391 int err;
392 struct sdei_crosscall_args *arg = data;
393
394 WARN_ON_ONCE(preemptible());
395
396 err = sdei_api_event_enable(arg->event->event_num);
397
398 sdei_cross_call_return(arg, err);
399 }
400
401 int sdei_event_enable(u32 event_num)
402 {
403 int err = -EINVAL;
404 struct sdei_event *event;
405
406 mutex_lock(&sdei_events_lock);
407 event = sdei_event_find(event_num);
408 if (!event) {
409 mutex_unlock(&sdei_events_lock);
410 return -ENOENT;
411 }
412
413 spin_lock(&sdei_list_lock);
414 event->reenable = true;
415 spin_unlock(&sdei_list_lock);
416
417 if (event->type == SDEI_EVENT_TYPE_SHARED)
418 err = sdei_api_event_enable(event->event_num);
419 else
420 err = sdei_do_cross_call(_local_event_enable, event);
421 mutex_unlock(&sdei_events_lock);
422
423 return err;
424 }
425 EXPORT_SYMBOL(sdei_event_enable);
426
427 static int sdei_api_event_disable(u32 event_num)
428 {
429 return invoke_sdei_fn(SDEI_1_0_FN_SDEI_EVENT_DISABLE, event_num, 0, 0,
430 0, 0, NULL);
431 }
432
433 static void _ipi_event_disable(void *data)
434 {
435 int err;
436 struct sdei_crosscall_args *arg = data;
437
438 err = sdei_api_event_disable(arg->event->event_num);
439
440 sdei_cross_call_return(arg, err);
441 }
442
443 int sdei_event_disable(u32 event_num)
444 {
445 int err = -EINVAL;
446 struct sdei_event *event;
447
448 mutex_lock(&sdei_events_lock);
449 event = sdei_event_find(event_num);
450 if (!event) {
451 mutex_unlock(&sdei_events_lock);
452 return -ENOENT;
453 }
454
455 spin_lock(&sdei_list_lock);
456 event->reenable = false;
457 spin_unlock(&sdei_list_lock);
458
459 if (event->type == SDEI_EVENT_TYPE_SHARED)
460 err = sdei_api_event_disable(event->event_num);
461 else
462 err = sdei_do_cross_call(_ipi_event_disable, event);
463 mutex_unlock(&sdei_events_lock);
464
465 return err;
466 }
467 EXPORT_SYMBOL(sdei_event_disable);
468
469 static int sdei_api_event_unregister(u32 event_num)
470 {
471 return invoke_sdei_fn(SDEI_1_0_FN_SDEI_EVENT_UNREGISTER, event_num, 0,
472 0, 0, 0, NULL);
473 }
474
475 /* Called directly by the hotplug callbacks */
476 static void _local_event_unregister(void *data)
477 {
478 int err;
479 struct sdei_crosscall_args *arg = data;
480
481 WARN_ON_ONCE(preemptible());
482
483 err = sdei_api_event_unregister(arg->event->event_num);
484
485 sdei_cross_call_return(arg, err);
486 }
487
488 static int _sdei_event_unregister(struct sdei_event *event)
489 {
490 lockdep_assert_held(&sdei_events_lock);
491
492 spin_lock(&sdei_list_lock);
493 event->reregister = false;
494 event->reenable = false;
495 spin_unlock(&sdei_list_lock);
496
497 if (event->type == SDEI_EVENT_TYPE_SHARED)
498 return sdei_api_event_unregister(event->event_num);
499
500 return sdei_do_cross_call(_local_event_unregister, event);
501 }
502
503 int sdei_event_unregister(u32 event_num)
504 {
505 int err;
506 struct sdei_event *event;
507
508 WARN_ON(in_nmi());
509
510 mutex_lock(&sdei_events_lock);
511 event = sdei_event_find(event_num);
512 do {
513 if (!event) {
514 pr_warn("Event %u not registered\n", event_num);
515 err = -ENOENT;
516 break;
517 }
518
519 err = _sdei_event_unregister(event);
520 if (err)
521 break;
522
523 sdei_event_destroy(event);
524 } while (0);
525 mutex_unlock(&sdei_events_lock);
526
527 return err;
528 }
529 EXPORT_SYMBOL(sdei_event_unregister);
530
531 /*
532 * unregister events, but don't destroy them as they are re-registered by
533 * sdei_reregister_shared().
534 */
535 static int sdei_unregister_shared(void)
536 {
537 int err = 0;
538 struct sdei_event *event;
539
540 mutex_lock(&sdei_events_lock);
541 spin_lock(&sdei_list_lock);
542 list_for_each_entry(event, &sdei_list, list) {
543 if (event->type != SDEI_EVENT_TYPE_SHARED)
544 continue;
545
546 err = _sdei_event_unregister(event);
547 if (err)
548 break;
549 }
550 spin_unlock(&sdei_list_lock);
551 mutex_unlock(&sdei_events_lock);
552
553 return err;
554 }
555
556 static int sdei_api_event_register(u32 event_num, unsigned long entry_point,
557 void *arg, u64 flags, u64 affinity)
558 {
559 return invoke_sdei_fn(SDEI_1_0_FN_SDEI_EVENT_REGISTER, event_num,
560 (unsigned long)entry_point, (unsigned long)arg,
561 flags, affinity, NULL);
562 }
563
564 /* Called directly by the hotplug callbacks */
565 static void _local_event_register(void *data)
566 {
567 int err;
568 struct sdei_registered_event *reg;
569 struct sdei_crosscall_args *arg = data;
570
571 WARN_ON(preemptible());
572
573 reg = per_cpu_ptr(arg->event->private_registered, smp_processor_id());
574 err = sdei_api_event_register(arg->event->event_num, sdei_entry_point,
575 reg, 0, 0);
576
577 sdei_cross_call_return(arg, err);
578 }
579
580 static int _sdei_event_register(struct sdei_event *event)
581 {
582 int err;
583
584 lockdep_assert_held(&sdei_events_lock);
585
586 spin_lock(&sdei_list_lock);
587 event->reregister = true;
588 spin_unlock(&sdei_list_lock);
589
590 if (event->type == SDEI_EVENT_TYPE_SHARED)
591 return sdei_api_event_register(event->event_num,
592 sdei_entry_point,
593 event->registered,
594 SDEI_EVENT_REGISTER_RM_ANY, 0);
595
596
597 err = sdei_do_cross_call(_local_event_register, event);
598 if (err) {
599 spin_lock(&sdei_list_lock);
600 event->reregister = false;
601 event->reenable = false;
602 spin_unlock(&sdei_list_lock);
603
604 sdei_do_cross_call(_local_event_unregister, event);
605 }
606
607 return err;
608 }
609
610 int sdei_event_register(u32 event_num, sdei_event_callback *cb, void *arg)
611 {
612 int err;
613 struct sdei_event *event;
614
615 WARN_ON(in_nmi());
616
617 mutex_lock(&sdei_events_lock);
618 do {
619 if (sdei_event_find(event_num)) {
620 pr_warn("Event %u already registered\n", event_num);
621 err = -EBUSY;
622 break;
623 }
624
625 event = sdei_event_create(event_num, cb, arg);
626 if (IS_ERR(event)) {
627 err = PTR_ERR(event);
628 pr_warn("Failed to create event %u: %d\n", event_num,
629 err);
630 break;
631 }
632
633 err = _sdei_event_register(event);
634 if (err) {
635 sdei_event_destroy(event);
636 pr_warn("Failed to register event %u: %d\n", event_num,
637 err);
638 }
639 } while (0);
640 mutex_unlock(&sdei_events_lock);
641
642 return err;
643 }
644 EXPORT_SYMBOL(sdei_event_register);
645
646 static int sdei_reregister_event(struct sdei_event *event)
647 {
648 int err;
649
650 lockdep_assert_held(&sdei_events_lock);
651
652 err = _sdei_event_register(event);
653 if (err) {
654 pr_err("Failed to re-register event %u\n", event->event_num);
655 sdei_event_destroy(event);
656 return err;
657 }
658
659 if (event->reenable) {
660 if (event->type == SDEI_EVENT_TYPE_SHARED)
661 err = sdei_api_event_enable(event->event_num);
662 else
663 err = sdei_do_cross_call(_local_event_enable, event);
664 }
665
666 if (err)
667 pr_err("Failed to re-enable event %u\n", event->event_num);
668
669 return err;
670 }
671
672 static int sdei_reregister_shared(void)
673 {
674 int err = 0;
675 struct sdei_event *event;
676
677 mutex_lock(&sdei_events_lock);
678 spin_lock(&sdei_list_lock);
679 list_for_each_entry(event, &sdei_list, list) {
680 if (event->type != SDEI_EVENT_TYPE_SHARED)
681 continue;
682
683 if (event->reregister) {
684 err = sdei_reregister_event(event);
685 if (err)
686 break;
687 }
688 }
689 spin_unlock(&sdei_list_lock);
690 mutex_unlock(&sdei_events_lock);
691
692 return err;
693 }
694
695 static int sdei_cpuhp_down(unsigned int cpu)
696 {
697 struct sdei_event *event;
698 struct sdei_crosscall_args arg;
699
700 /* un-register private events */
701 spin_lock(&sdei_list_lock);
702 list_for_each_entry(event, &sdei_list, list) {
703 if (event->type == SDEI_EVENT_TYPE_SHARED)
704 continue;
705
706 CROSSCALL_INIT(arg, event);
707 /* call the cross-call function locally... */
708 _local_event_unregister(&arg);
709 if (arg.first_error)
710 pr_err("Failed to unregister event %u: %d\n",
711 event->event_num, arg.first_error);
712 }
713 spin_unlock(&sdei_list_lock);
714
715 return sdei_mask_local_cpu();
716 }
717
718 static int sdei_cpuhp_up(unsigned int cpu)
719 {
720 struct sdei_event *event;
721 struct sdei_crosscall_args arg;
722
723 /* re-register/enable private events */
724 spin_lock(&sdei_list_lock);
725 list_for_each_entry(event, &sdei_list, list) {
726 if (event->type == SDEI_EVENT_TYPE_SHARED)
727 continue;
728
729 if (event->reregister) {
730 CROSSCALL_INIT(arg, event);
731 /* call the cross-call function locally... */
732 _local_event_register(&arg);
733 if (arg.first_error)
734 pr_err("Failed to re-register event %u: %d\n",
735 event->event_num, arg.first_error);
736 }
737
738 if (event->reenable) {
739 CROSSCALL_INIT(arg, event);
740 _local_event_enable(&arg);
741 if (arg.first_error)
742 pr_err("Failed to re-enable event %u: %d\n",
743 event->event_num, arg.first_error);
744 }
745 }
746 spin_unlock(&sdei_list_lock);
747
748 return sdei_unmask_local_cpu();
749 }
750
751 /* When entering idle, mask/unmask events for this cpu */
752 static int sdei_pm_notifier(struct notifier_block *nb, unsigned long action,
753 void *data)
754 {
755 int rv;
756
757 switch (action) {
758 case CPU_PM_ENTER:
759 rv = sdei_mask_local_cpu();
760 break;
761 case CPU_PM_EXIT:
762 case CPU_PM_ENTER_FAILED:
763 rv = sdei_unmask_local_cpu();
764 break;
765 default:
766 return NOTIFY_DONE;
767 }
768
769 if (rv)
770 return notifier_from_errno(rv);
771
772 return NOTIFY_OK;
773 }
774
775 static struct notifier_block sdei_pm_nb = {
776 .notifier_call = sdei_pm_notifier,
777 };
778
779 static int sdei_device_suspend(struct device *dev)
780 {
781 on_each_cpu(_ipi_mask_cpu, NULL, true);
782
783 return 0;
784 }
785
786 static int sdei_device_resume(struct device *dev)
787 {
788 on_each_cpu(_ipi_unmask_cpu, NULL, true);
789
790 return 0;
791 }
792
793 /*
794 * We need all events to be reregistered when we resume from hibernate.
795 *
796 * The sequence is freeze->thaw. Reboot. freeze->restore. We unregister
797 * events during freeze, then re-register and re-enable them during thaw
798 * and restore.
799 */
800 static int sdei_device_freeze(struct device *dev)
801 {
802 int err;
803
804 /* unregister private events */
805 cpuhp_remove_state(CPUHP_AP_ARM_SDEI_STARTING);
806
807 err = sdei_unregister_shared();
808 if (err)
809 return err;
810
811 return 0;
812 }
813
814 static int sdei_device_thaw(struct device *dev)
815 {
816 int err;
817
818 /* re-register shared events */
819 err = sdei_reregister_shared();
820 if (err) {
821 pr_warn("Failed to re-register shared events...\n");
822 sdei_mark_interface_broken();
823 return err;
824 }
825
826 err = cpuhp_setup_state(CPUHP_AP_ARM_SDEI_STARTING, "SDEI",
827 &sdei_cpuhp_up, &sdei_cpuhp_down);
828 if (err)
829 pr_warn("Failed to re-register CPU hotplug notifier...\n");
830
831 return err;
832 }
833
834 static int sdei_device_restore(struct device *dev)
835 {
836 int err;
837
838 err = sdei_platform_reset();
839 if (err)
840 return err;
841
842 return sdei_device_thaw(dev);
843 }
844
845 static const struct dev_pm_ops sdei_pm_ops = {
846 .suspend = sdei_device_suspend,
847 .resume = sdei_device_resume,
848 .freeze = sdei_device_freeze,
849 .thaw = sdei_device_thaw,
850 .restore = sdei_device_restore,
851 };
852
853 /*
854 * Mask all CPUs and unregister all events on panic, reboot or kexec.
855 */
856 static int sdei_reboot_notifier(struct notifier_block *nb, unsigned long action,
857 void *data)
858 {
859 /*
860 * We are going to reset the interface, after this there is no point
861 * doing work when we take CPUs offline.
862 */
863 cpuhp_remove_state(CPUHP_AP_ARM_SDEI_STARTING);
864
865 sdei_platform_reset();
866
867 return NOTIFY_OK;
868 }
869
870 static struct notifier_block sdei_reboot_nb = {
871 .notifier_call = sdei_reboot_notifier,
872 };
873
874 static void sdei_smccc_smc(unsigned long function_id,
875 unsigned long arg0, unsigned long arg1,
876 unsigned long arg2, unsigned long arg3,
877 unsigned long arg4, struct arm_smccc_res *res)
878 {
879 arm_smccc_smc(function_id, arg0, arg1, arg2, arg3, arg4, 0, 0, res);
880 }
881
882 static void sdei_smccc_hvc(unsigned long function_id,
883 unsigned long arg0, unsigned long arg1,
884 unsigned long arg2, unsigned long arg3,
885 unsigned long arg4, struct arm_smccc_res *res)
886 {
887 arm_smccc_hvc(function_id, arg0, arg1, arg2, arg3, arg4, 0, 0, res);
888 }
889
890 static int sdei_get_conduit(struct platform_device *pdev)
891 {
892 const char *method;
893 struct device_node *np = pdev->dev.of_node;
894
895 sdei_firmware_call = NULL;
896 if (np) {
897 if (of_property_read_string(np, "method", &method)) {
898 pr_warn("missing \"method\" property\n");
899 return CONDUIT_INVALID;
900 }
901
902 if (!strcmp("hvc", method)) {
903 sdei_firmware_call = &sdei_smccc_hvc;
904 return CONDUIT_HVC;
905 } else if (!strcmp("smc", method)) {
906 sdei_firmware_call = &sdei_smccc_smc;
907 return CONDUIT_SMC;
908 }
909
910 pr_warn("invalid \"method\" property: %s\n", method);
911 } else if (IS_ENABLED(CONFIG_ACPI) && !acpi_disabled) {
912 if (acpi_psci_use_hvc()) {
913 sdei_firmware_call = &sdei_smccc_hvc;
914 return CONDUIT_HVC;
915 } else {
916 sdei_firmware_call = &sdei_smccc_smc;
917 return CONDUIT_SMC;
918 }
919 }
920
921 return CONDUIT_INVALID;
922 }
923
924 static int sdei_probe(struct platform_device *pdev)
925 {
926 int err;
927 u64 ver = 0;
928 int conduit;
929
930 conduit = sdei_get_conduit(pdev);
931 if (!sdei_firmware_call)
932 return 0;
933
934 err = sdei_api_get_version(&ver);
935 if (err == -EOPNOTSUPP)
936 pr_err("advertised but not implemented in platform firmware\n");
937 if (err) {
938 pr_err("Failed to get SDEI version: %d\n", err);
939 sdei_mark_interface_broken();
940 return err;
941 }
942
943 pr_info("SDEIv%d.%d (0x%x) detected in firmware.\n",
944 (int)SDEI_VERSION_MAJOR(ver), (int)SDEI_VERSION_MINOR(ver),
945 (int)SDEI_VERSION_VENDOR(ver));
946
947 if (SDEI_VERSION_MAJOR(ver) != 1) {
948 pr_warn("Conflicting SDEI version detected.\n");
949 sdei_mark_interface_broken();
950 return -EINVAL;
951 }
952
953 err = sdei_platform_reset();
954 if (err)
955 return err;
956
957 sdei_entry_point = sdei_arch_get_entry_point(conduit);
958 if (!sdei_entry_point) {
959 /* Not supported due to hardware or boot configuration */
960 sdei_mark_interface_broken();
961 return 0;
962 }
963
964 err = cpu_pm_register_notifier(&sdei_pm_nb);
965 if (err) {
966 pr_warn("Failed to register CPU PM notifier...\n");
967 goto error;
968 }
969
970 err = register_reboot_notifier(&sdei_reboot_nb);
971 if (err) {
972 pr_warn("Failed to register reboot notifier...\n");
973 goto remove_cpupm;
974 }
975
976 err = cpuhp_setup_state(CPUHP_AP_ARM_SDEI_STARTING, "SDEI",
977 &sdei_cpuhp_up, &sdei_cpuhp_down);
978 if (err) {
979 pr_warn("Failed to register CPU hotplug notifier...\n");
980 goto remove_reboot;
981 }
982
983 return 0;
984
985 remove_reboot:
986 unregister_reboot_notifier(&sdei_reboot_nb);
987
988 remove_cpupm:
989 cpu_pm_unregister_notifier(&sdei_pm_nb);
990
991 error:
992 sdei_mark_interface_broken();
993 return err;
994 }
995
996 static const struct of_device_id sdei_of_match[] = {
997 { .compatible = "arm,sdei-1.0" },
998 {}
999 };
1000
1001 static struct platform_driver sdei_driver = {
1002 .driver = {
1003 .name = "sdei",
1004 .pm = &sdei_pm_ops,
1005 .of_match_table = sdei_of_match,
1006 },
1007 .probe = sdei_probe,
1008 };
1009
1010 static bool __init sdei_present_dt(void)
1011 {
1012 struct platform_device *pdev;
1013 struct device_node *np, *fw_np;
1014
1015 fw_np = of_find_node_by_name(NULL, "firmware");
1016 if (!fw_np)
1017 return false;
1018
1019 np = of_find_matching_node(fw_np, sdei_of_match);
1020 of_node_put(fw_np);
1021 if (!np)
1022 return false;
1023
1024 pdev = of_platform_device_create(np, sdei_driver.driver.name, NULL);
1025 of_node_put(np);
1026 if (!pdev)
1027 return false;
1028
1029 return true;
1030 }
1031
1032 static bool __init sdei_present_acpi(void)
1033 {
1034 acpi_status status;
1035 struct platform_device *pdev;
1036 struct acpi_table_header *sdei_table_header;
1037
1038 if (acpi_disabled)
1039 return false;
1040
1041 status = acpi_get_table(ACPI_SIG_SDEI, 0, &sdei_table_header);
1042 if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
1043 const char *msg = acpi_format_exception(status);
1044
1045 pr_info("Failed to get ACPI:SDEI table, %s\n", msg);
1046 }
1047 if (ACPI_FAILURE(status))
1048 return false;
1049
1050 pdev = platform_device_register_simple(sdei_driver.driver.name, 0, NULL,
1051 0);
1052 if (IS_ERR(pdev))
1053 return false;
1054
1055 return true;
1056 }
1057
1058 static int __init sdei_init(void)
1059 {
1060 if (sdei_present_dt() || sdei_present_acpi())
1061 platform_driver_register(&sdei_driver);
1062
1063 return 0;
1064 }
1065
1066 /*
1067 * On an ACPI system SDEI needs to be ready before HEST:GHES tries to register
1068 * its events. ACPI is initialised from a subsys_initcall(), GHES is initialised
1069 * by device_initcall(). We want to be called in the middle.
1070 */
1071 subsys_initcall_sync(sdei_init);
1072
1073 int sdei_event_handler(struct pt_regs *regs,
1074 struct sdei_registered_event *arg)
1075 {
1076 int err;
1077 mm_segment_t orig_addr_limit;
1078 u32 event_num = arg->event_num;
1079
1080 orig_addr_limit = get_fs();
1081 set_fs(USER_DS);
1082
1083 err = arg->callback(event_num, regs, arg->callback_arg);
1084 if (err)
1085 pr_err_ratelimited("event %u on CPU %u failed with error: %d\n",
1086 event_num, smp_processor_id(), err);
1087
1088 set_fs(orig_addr_limit);
1089
1090 return err;
1091 }
1092 NOKPROBE_SYMBOL(sdei_event_handler);
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