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