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  1/*
  2 * Copyright 2014 Advanced Micro Devices, Inc.
  3 *
  4 * Permission is hereby granted, free of charge, to any person obtaining a
  5 * copy of this software and associated documentation files (the "Software"),
  6 * to deal in the Software without restriction, including without limitation
  7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  8 * and/or sell copies of the Software, and to permit persons to whom the
  9 * Software is furnished to do so, subject to the following conditions:
 10 *
 11 * The above copyright notice and this permission notice shall be included in
 12 * all copies or substantial portions of the Software.
 13 *
 14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 17 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
 18 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 19 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 20 * OTHER DEALINGS IN THE SOFTWARE.
 21 */
 22
 23#include <linux/mm_types.h>
 24#include <linux/slab.h>
 25#include <linux/types.h>
 26#include <linux/sched/signal.h>
 27#include <linux/sched/mm.h>
 28#include <linux/uaccess.h>
 29#include <linux/mman.h>
 30#include <linux/memory.h>
 31#include "kfd_priv.h"
 32#include "kfd_events.h"
 33#include "kfd_iommu.h"
 34#include <linux/device.h>
 35
 36/*
 37 * Wrapper around wait_queue_entry_t
 38 */
 39struct kfd_event_waiter {
 40	wait_queue_entry_t wait;
 41	struct kfd_event *event; /* Event to wait for */
 42	bool activated;		 /* Becomes true when event is signaled */
 43};
 44
 45/*
 46 * Each signal event needs a 64-bit signal slot where the signaler will write
 47 * a 1 before sending an interrupt. (This is needed because some interrupts
 48 * do not contain enough spare data bits to identify an event.)
 49 * We get whole pages and map them to the process VA.
 50 * Individual signal events use their event_id as slot index.
 51 */
 52struct kfd_signal_page {
 53	uint64_t *kernel_address;
 54	uint64_t __user *user_address;
 55	bool need_to_free_pages;
 56};
 57
 58
 59static uint64_t *page_slots(struct kfd_signal_page *page)
 60{
 61	return page->kernel_address;
 62}
 63
 64static struct kfd_signal_page *allocate_signal_page(struct kfd_process *p)
 65{
 66	void *backing_store;
 67	struct kfd_signal_page *page;
 68
 69	page = kzalloc(sizeof(*page), GFP_KERNEL);
 70	if (!page)
 71		return NULL;
 72
 73	backing_store = (void *) __get_free_pages(GFP_KERNEL,
 74					get_order(KFD_SIGNAL_EVENT_LIMIT * 8));
 75	if (!backing_store)
 76		goto fail_alloc_signal_store;
 77
 78	/* Initialize all events to unsignaled */
 79	memset(backing_store, (uint8_t) UNSIGNALED_EVENT_SLOT,
 80	       KFD_SIGNAL_EVENT_LIMIT * 8);
 81
 82	page->kernel_address = backing_store;
 83	page->need_to_free_pages = true;
 84	pr_debug("Allocated new event signal page at %p, for process %p\n",
 85			page, p);
 86
 87	return page;
 88
 89fail_alloc_signal_store:
 90	kfree(page);
 91	return NULL;
 92}
 93
 94static int allocate_event_notification_slot(struct kfd_process *p,
 95					    struct kfd_event *ev)
 96{
 97	int id;
 98
 99	if (!p->signal_page) {
100		p->signal_page = allocate_signal_page(p);
101		if (!p->signal_page)
102			return -ENOMEM;
103		/* Oldest user mode expects 256 event slots */
104		p->signal_mapped_size = 256*8;
105	}
106
107	/*
108	 * Compatibility with old user mode: Only use signal slots
109	 * user mode has mapped, may be less than
110	 * KFD_SIGNAL_EVENT_LIMIT. This also allows future increase
111	 * of the event limit without breaking user mode.
112	 */
113	id = idr_alloc(&p->event_idr, ev, 0, p->signal_mapped_size / 8,
114		       GFP_KERNEL);
115	if (id < 0)
116		return id;
117
118	ev->event_id = id;
119	page_slots(p->signal_page)[id] = UNSIGNALED_EVENT_SLOT;
120
121	return 0;
122}
123
124/*
125 * Assumes that p->event_mutex is held and of course that p is not going
126 * away (current or locked).
127 */
128static struct kfd_event *lookup_event_by_id(struct kfd_process *p, uint32_t id)
129{
130	return idr_find(&p->event_idr, id);
131}
132
133/**
134 * lookup_signaled_event_by_partial_id - Lookup signaled event from partial ID
135 * @p:     Pointer to struct kfd_process
136 * @id:    ID to look up
137 * @bits:  Number of valid bits in @id
138 *
139 * Finds the first signaled event with a matching partial ID. If no
140 * matching signaled event is found, returns NULL. In that case the
141 * caller should assume that the partial ID is invalid and do an
142 * exhaustive search of all siglaned events.
143 *
144 * If multiple events with the same partial ID signal at the same
145 * time, they will be found one interrupt at a time, not necessarily
146 * in the same order the interrupts occurred. As long as the number of
147 * interrupts is correct, all signaled events will be seen by the
148 * driver.
149 */
150static struct kfd_event *lookup_signaled_event_by_partial_id(
151	struct kfd_process *p, uint32_t id, uint32_t bits)
152{
153	struct kfd_event *ev;
154
155	if (!p->signal_page || id >= KFD_SIGNAL_EVENT_LIMIT)
156		return NULL;
157
158	/* Fast path for the common case that @id is not a partial ID
159	 * and we only need a single lookup.
160	 */
161	if (bits > 31 || (1U << bits) >= KFD_SIGNAL_EVENT_LIMIT) {
162		if (page_slots(p->signal_page)[id] == UNSIGNALED_EVENT_SLOT)
163			return NULL;
164
165		return idr_find(&p->event_idr, id);
166	}
167
168	/* General case for partial IDs: Iterate over all matching IDs
169	 * and find the first one that has signaled.
170	 */
171	for (ev = NULL; id < KFD_SIGNAL_EVENT_LIMIT && !ev; id += 1U << bits) {
172		if (page_slots(p->signal_page)[id] == UNSIGNALED_EVENT_SLOT)
173			continue;
174
175		ev = idr_find(&p->event_idr, id);
176	}
177
178	return ev;
179}
180
181static int create_signal_event(struct file *devkfd,
182				struct kfd_process *p,
183				struct kfd_event *ev)
184{
185	int ret;
186
187	if (p->signal_mapped_size &&
188	    p->signal_event_count == p->signal_mapped_size / 8) {
189		if (!p->signal_event_limit_reached) {
190			pr_warn("Signal event wasn't created because limit was reached\n");
191			p->signal_event_limit_reached = true;
192		}
193		return -ENOSPC;
194	}
195
196	ret = allocate_event_notification_slot(p, ev);
197	if (ret) {
198		pr_warn("Signal event wasn't created because out of kernel memory\n");
199		return ret;
200	}
201
202	p->signal_event_count++;
203
204	ev->user_signal_address = &p->signal_page->user_address[ev->event_id];
205	pr_debug("Signal event number %zu created with id %d, address %p\n",
206			p->signal_event_count, ev->event_id,
207			ev->user_signal_address);
208
209	return 0;
210}
211
212static int create_other_event(struct kfd_process *p, struct kfd_event *ev)
213{
214	/* Cast KFD_LAST_NONSIGNAL_EVENT to uint32_t. This allows an
215	 * intentional integer overflow to -1 without a compiler
216	 * warning. idr_alloc treats a negative value as "maximum
217	 * signed integer".
218	 */
219	int id = idr_alloc(&p->event_idr, ev, KFD_FIRST_NONSIGNAL_EVENT_ID,
220			   (uint32_t)KFD_LAST_NONSIGNAL_EVENT_ID + 1,
221			   GFP_KERNEL);
222
223	if (id < 0)
224		return id;
225	ev->event_id = id;
226
227	return 0;
228}
229
230void kfd_event_init_process(struct kfd_process *p)
231{
232	mutex_init(&p->event_mutex);
233	idr_init(&p->event_idr);
234	p->signal_page = NULL;
235	p->signal_event_count = 0;
236}
237
238static void destroy_event(struct kfd_process *p, struct kfd_event *ev)
239{
240	struct kfd_event_waiter *waiter;
241
242	/* Wake up pending waiters. They will return failure */
243	list_for_each_entry(waiter, &ev->wq.head, wait.entry)
244		waiter->event = NULL;
245	wake_up_all(&ev->wq);
246
247	if (ev->type == KFD_EVENT_TYPE_SIGNAL ||
248	    ev->type == KFD_EVENT_TYPE_DEBUG)
249		p->signal_event_count--;
250
251	idr_remove(&p->event_idr, ev->event_id);
252	kfree(ev);
253}
254
255static void destroy_events(struct kfd_process *p)
256{
257	struct kfd_event *ev;
258	uint32_t id;
259
260	idr_for_each_entry(&p->event_idr, ev, id)
261		destroy_event(p, ev);
262	idr_destroy(&p->event_idr);
263}
264
265/*
266 * We assume that the process is being destroyed and there is no need to
267 * unmap the pages or keep bookkeeping data in order.
268 */
269static void shutdown_signal_page(struct kfd_process *p)
270{
271	struct kfd_signal_page *page = p->signal_page;
272
273	if (page) {
274		if (page->need_to_free_pages)
275			free_pages((unsigned long)page->kernel_address,
276				   get_order(KFD_SIGNAL_EVENT_LIMIT * 8));
277		kfree(page);
278	}
279}
280
281void kfd_event_free_process(struct kfd_process *p)
282{
283	destroy_events(p);
284	shutdown_signal_page(p);
285}
286
287static bool event_can_be_gpu_signaled(const struct kfd_event *ev)
288{
289	return ev->type == KFD_EVENT_TYPE_SIGNAL ||
290					ev->type == KFD_EVENT_TYPE_DEBUG;
291}
292
293static bool event_can_be_cpu_signaled(const struct kfd_event *ev)
294{
295	return ev->type == KFD_EVENT_TYPE_SIGNAL;
296}
297
298int kfd_event_page_set(struct kfd_process *p, void *kernel_address,
299		       uint64_t size)
300{
301	struct kfd_signal_page *page;
302
303	if (p->signal_page)
304		return -EBUSY;
305
306	page = kzalloc(sizeof(*page), GFP_KERNEL);
307	if (!page)
308		return -ENOMEM;
309
310	/* Initialize all events to unsignaled */
311	memset(kernel_address, (uint8_t) UNSIGNALED_EVENT_SLOT,
312	       KFD_SIGNAL_EVENT_LIMIT * 8);
313
314	page->kernel_address = kernel_address;
315
316	p->signal_page = page;
317	p->signal_mapped_size = size;
318
319	return 0;
320}
321
322int kfd_event_create(struct file *devkfd, struct kfd_process *p,
323		     uint32_t event_type, bool auto_reset, uint32_t node_id,
324		     uint32_t *event_id, uint32_t *event_trigger_data,
325		     uint64_t *event_page_offset, uint32_t *event_slot_index)
326{
327	int ret = 0;
328	struct kfd_event *ev = kzalloc(sizeof(*ev), GFP_KERNEL);
329
330	if (!ev)
331		return -ENOMEM;
332
333	ev->type = event_type;
334	ev->auto_reset = auto_reset;
335	ev->signaled = false;
336
337	init_waitqueue_head(&ev->wq);
338
339	*event_page_offset = 0;
340
341	mutex_lock(&p->event_mutex);
342
343	switch (event_type) {
344	case KFD_EVENT_TYPE_SIGNAL:
345	case KFD_EVENT_TYPE_DEBUG:
346		ret = create_signal_event(devkfd, p, ev);
347		if (!ret) {
348			*event_page_offset = KFD_MMAP_EVENTS_MASK;
349			*event_page_offset <<= PAGE_SHIFT;
350			*event_slot_index = ev->event_id;
351		}
352		break;
353	default:
354		ret = create_other_event(p, ev);
355		break;
356	}
357
358	if (!ret) {
359		*event_id = ev->event_id;
360		*event_trigger_data = ev->event_id;
361	} else {
362		kfree(ev);
363	}
364
365	mutex_unlock(&p->event_mutex);
366
367	return ret;
368}
369
370/* Assumes that p is current. */
371int kfd_event_destroy(struct kfd_process *p, uint32_t event_id)
372{
373	struct kfd_event *ev;
374	int ret = 0;
375
376	mutex_lock(&p->event_mutex);
377
378	ev = lookup_event_by_id(p, event_id);
379
380	if (ev)
381		destroy_event(p, ev);
382	else
383		ret = -EINVAL;
384
385	mutex_unlock(&p->event_mutex);
386	return ret;
387}
388
389static void set_event(struct kfd_event *ev)
390{
391	struct kfd_event_waiter *waiter;
392
393	/* Auto reset if the list is non-empty and we're waking
394	 * someone. waitqueue_active is safe here because we're
395	 * protected by the p->event_mutex, which is also held when
396	 * updating the wait queues in kfd_wait_on_events.
397	 */
398	ev->signaled = !ev->auto_reset || !waitqueue_active(&ev->wq);
399
400	list_for_each_entry(waiter, &ev->wq.head, wait.entry)
401		waiter->activated = true;
402
403	wake_up_all(&ev->wq);
404}
405
406/* Assumes that p is current. */
407int kfd_set_event(struct kfd_process *p, uint32_t event_id)
408{
409	int ret = 0;
410	struct kfd_event *ev;
411
412	mutex_lock(&p->event_mutex);
413
414	ev = lookup_event_by_id(p, event_id);
415
416	if (ev && event_can_be_cpu_signaled(ev))
417		set_event(ev);
418	else
419		ret = -EINVAL;
420
421	mutex_unlock(&p->event_mutex);
422	return ret;
423}
424
425static void reset_event(struct kfd_event *ev)
426{
427	ev->signaled = false;
428}
429
430/* Assumes that p is current. */
431int kfd_reset_event(struct kfd_process *p, uint32_t event_id)
432{
433	int ret = 0;
434	struct kfd_event *ev;
435
436	mutex_lock(&p->event_mutex);
437
438	ev = lookup_event_by_id(p, event_id);
439
440	if (ev && event_can_be_cpu_signaled(ev))
441		reset_event(ev);
442	else
443		ret = -EINVAL;
444
445	mutex_unlock(&p->event_mutex);
446	return ret;
447
448}
449
450static void acknowledge_signal(struct kfd_process *p, struct kfd_event *ev)
451{
452	page_slots(p->signal_page)[ev->event_id] = UNSIGNALED_EVENT_SLOT;
453}
454
455static void set_event_from_interrupt(struct kfd_process *p,
456					struct kfd_event *ev)
457{
458	if (ev && event_can_be_gpu_signaled(ev)) {
459		acknowledge_signal(p, ev);
460		set_event(ev);
461	}
462}
463
464void kfd_signal_event_interrupt(unsigned int pasid, uint32_t partial_id,
465				uint32_t valid_id_bits)
466{
467	struct kfd_event *ev = NULL;
468
469	/*
470	 * Because we are called from arbitrary context (workqueue) as opposed
471	 * to process context, kfd_process could attempt to exit while we are
472	 * running so the lookup function increments the process ref count.
473	 */
474	struct kfd_process *p = kfd_lookup_process_by_pasid(pasid);
475
476	if (!p)
477		return; /* Presumably process exited. */
478
479	mutex_lock(&p->event_mutex);
480
481	if (valid_id_bits)
482		ev = lookup_signaled_event_by_partial_id(p, partial_id,
483							 valid_id_bits);
484	if (ev) {
485		set_event_from_interrupt(p, ev);
486	} else if (p->signal_page) {
487		/*
488		 * Partial ID lookup failed. Assume that the event ID
489		 * in the interrupt payload was invalid and do an
490		 * exhaustive search of signaled events.
491		 */
492		uint64_t *slots = page_slots(p->signal_page);
493		uint32_t id;
494
495		if (valid_id_bits)
496			pr_debug_ratelimited("Partial ID invalid: %u (%u valid bits)\n",
497					     partial_id, valid_id_bits);
498
499		if (p->signal_event_count < KFD_SIGNAL_EVENT_LIMIT/2) {
500			/* With relatively few events, it's faster to
501			 * iterate over the event IDR
502			 */
503			idr_for_each_entry(&p->event_idr, ev, id) {
504				if (id >= KFD_SIGNAL_EVENT_LIMIT)
505					break;
506
507				if (slots[id] != UNSIGNALED_EVENT_SLOT)
508					set_event_from_interrupt(p, ev);
509			}
510		} else {
511			/* With relatively many events, it's faster to
512			 * iterate over the signal slots and lookup
513			 * only signaled events from the IDR.
514			 */
515			for (id = 0; id < KFD_SIGNAL_EVENT_LIMIT; id++)
516				if (slots[id] != UNSIGNALED_EVENT_SLOT) {
517					ev = lookup_event_by_id(p, id);
518					set_event_from_interrupt(p, ev);
519				}
520		}
521	}
522
523	mutex_unlock(&p->event_mutex);
524	kfd_unref_process(p);
525}
526
527static struct kfd_event_waiter *alloc_event_waiters(uint32_t num_events)
528{
529	struct kfd_event_waiter *event_waiters;
530	uint32_t i;
531
532	event_waiters = kmalloc_array(num_events,
533					sizeof(struct kfd_event_waiter),
534					GFP_KERNEL);
535
536	for (i = 0; (event_waiters) && (i < num_events) ; i++) {
537		init_wait(&event_waiters[i].wait);
538		event_waiters[i].activated = false;
539	}
540
541	return event_waiters;
542}
543
544static int init_event_waiter_get_status(struct kfd_process *p,
545		struct kfd_event_waiter *waiter,
546		uint32_t event_id)
547{
548	struct kfd_event *ev = lookup_event_by_id(p, event_id);
549
550	if (!ev)
551		return -EINVAL;
552
553	waiter->event = ev;
554	waiter->activated = ev->signaled;
555	ev->signaled = ev->signaled && !ev->auto_reset;
556
557	return 0;
558}
559
560static void init_event_waiter_add_to_waitlist(struct kfd_event_waiter *waiter)
561{
562	struct kfd_event *ev = waiter->event;
563
564	/* Only add to the wait list if we actually need to
565	 * wait on this event.
566	 */
567	if (!waiter->activated)
568		add_wait_queue(&ev->wq, &waiter->wait);
569}
570
571/* test_event_condition - Test condition of events being waited for
572 * @all:           Return completion only if all events have signaled
573 * @num_events:    Number of events to wait for
574 * @event_waiters: Array of event waiters, one per event
575 *
576 * Returns KFD_IOC_WAIT_RESULT_COMPLETE if all (or one) event(s) have
577 * signaled. Returns KFD_IOC_WAIT_RESULT_TIMEOUT if no (or not all)
578 * events have signaled. Returns KFD_IOC_WAIT_RESULT_FAIL if any of
579 * the events have been destroyed.
580 */
581static uint32_t test_event_condition(bool all, uint32_t num_events,
582				struct kfd_event_waiter *event_waiters)
583{
584	uint32_t i;
585	uint32_t activated_count = 0;
586
587	for (i = 0; i < num_events; i++) {
588		if (!event_waiters[i].event)
589			return KFD_IOC_WAIT_RESULT_FAIL;
590
591		if (event_waiters[i].activated) {
592			if (!all)
593				return KFD_IOC_WAIT_RESULT_COMPLETE;
594
595			activated_count++;
596		}
597	}
598
599	return activated_count == num_events ?
600		KFD_IOC_WAIT_RESULT_COMPLETE : KFD_IOC_WAIT_RESULT_TIMEOUT;
601}
602
603/*
604 * Copy event specific data, if defined.
605 * Currently only memory exception events have additional data to copy to user
606 */
607static int copy_signaled_event_data(uint32_t num_events,
608		struct kfd_event_waiter *event_waiters,
609		struct kfd_event_data __user *data)
610{
611	struct kfd_hsa_memory_exception_data *src;
612	struct kfd_hsa_memory_exception_data __user *dst;
613	struct kfd_event_waiter *waiter;
614	struct kfd_event *event;
615	uint32_t i;
616
617	for (i = 0; i < num_events; i++) {
618		waiter = &event_waiters[i];
619		event = waiter->event;
620		if (waiter->activated && event->type == KFD_EVENT_TYPE_MEMORY) {
621			dst = &data[i].memory_exception_data;
622			src = &event->memory_exception_data;
623			if (copy_to_user(dst, src,
624				sizeof(struct kfd_hsa_memory_exception_data)))
625				return -EFAULT;
626		}
627	}
628
629	return 0;
630
631}
632
633
634
635static long user_timeout_to_jiffies(uint32_t user_timeout_ms)
636{
637	if (user_timeout_ms == KFD_EVENT_TIMEOUT_IMMEDIATE)
638		return 0;
639
640	if (user_timeout_ms == KFD_EVENT_TIMEOUT_INFINITE)
641		return MAX_SCHEDULE_TIMEOUT;
642
643	/*
644	 * msecs_to_jiffies interprets all values above 2^31-1 as infinite,
645	 * but we consider them finite.
646	 * This hack is wrong, but nobody is likely to notice.
647	 */
648	user_timeout_ms = min_t(uint32_t, user_timeout_ms, 0x7FFFFFFF);
649
650	return msecs_to_jiffies(user_timeout_ms) + 1;
651}
652
653static void free_waiters(uint32_t num_events, struct kfd_event_waiter *waiters)
654{
655	uint32_t i;
656
657	for (i = 0; i < num_events; i++)
658		if (waiters[i].event)
659			remove_wait_queue(&waiters[i].event->wq,
660					  &waiters[i].wait);
661
662	kfree(waiters);
663}
664
665int kfd_wait_on_events(struct kfd_process *p,
666		       uint32_t num_events, void __user *data,
667		       bool all, uint32_t user_timeout_ms,
668		       uint32_t *wait_result)
669{
670	struct kfd_event_data __user *events =
671			(struct kfd_event_data __user *) data;
672	uint32_t i;
673	int ret = 0;
674
675	struct kfd_event_waiter *event_waiters = NULL;
676	long timeout = user_timeout_to_jiffies(user_timeout_ms);
677
678	event_waiters = alloc_event_waiters(num_events);
679	if (!event_waiters) {
680		ret = -ENOMEM;
681		goto out;
682	}
683
684	mutex_lock(&p->event_mutex);
685
686	for (i = 0; i < num_events; i++) {
687		struct kfd_event_data event_data;
688
689		if (copy_from_user(&event_data, &events[i],
690				sizeof(struct kfd_event_data))) {
691			ret = -EFAULT;
692			goto out_unlock;
693		}
694
695		ret = init_event_waiter_get_status(p, &event_waiters[i],
696				event_data.event_id);
697		if (ret)
698			goto out_unlock;
699	}
700
701	/* Check condition once. */
702	*wait_result = test_event_condition(all, num_events, event_waiters);
703	if (*wait_result == KFD_IOC_WAIT_RESULT_COMPLETE) {
704		ret = copy_signaled_event_data(num_events,
705					       event_waiters, events);
706		goto out_unlock;
707	} else if (WARN_ON(*wait_result == KFD_IOC_WAIT_RESULT_FAIL)) {
708		/* This should not happen. Events shouldn't be
709		 * destroyed while we're holding the event_mutex
710		 */
711		goto out_unlock;
712	}
713
714	/* Add to wait lists if we need to wait. */
715	for (i = 0; i < num_events; i++)
716		init_event_waiter_add_to_waitlist(&event_waiters[i]);
717
718	mutex_unlock(&p->event_mutex);
719
720	while (true) {
721		if (fatal_signal_pending(current)) {
722			ret = -EINTR;
723			break;
724		}
725
726		if (signal_pending(current)) {
727			/*
728			 * This is wrong when a nonzero, non-infinite timeout
729			 * is specified. We need to use
730			 * ERESTARTSYS_RESTARTBLOCK, but struct restart_block
731			 * contains a union with data for each user and it's
732			 * in generic kernel code that I don't want to
733			 * touch yet.
734			 */
735			ret = -ERESTARTSYS;
736			break;
737		}
738
739		/* Set task state to interruptible sleep before
740		 * checking wake-up conditions. A concurrent wake-up
741		 * will put the task back into runnable state. In that
742		 * case schedule_timeout will not put the task to
743		 * sleep and we'll get a chance to re-check the
744		 * updated conditions almost immediately. Otherwise,
745		 * this race condition would lead to a soft hang or a
746		 * very long sleep.
747		 */
748		set_current_state(TASK_INTERRUPTIBLE);
749
750		*wait_result = test_event_condition(all, num_events,
751						    event_waiters);
752		if (*wait_result != KFD_IOC_WAIT_RESULT_TIMEOUT)
753			break;
754
755		if (timeout <= 0)
756			break;
757
758		timeout = schedule_timeout(timeout);
759	}
760	__set_current_state(TASK_RUNNING);
761
762	/* copy_signaled_event_data may sleep. So this has to happen
763	 * after the task state is set back to RUNNING.
764	 */
765	if (!ret && *wait_result == KFD_IOC_WAIT_RESULT_COMPLETE)
766		ret = copy_signaled_event_data(num_events,
767					       event_waiters, events);
768
769	mutex_lock(&p->event_mutex);
770out_unlock:
771	free_waiters(num_events, event_waiters);
772	mutex_unlock(&p->event_mutex);
773out:
774	if (ret)
775		*wait_result = KFD_IOC_WAIT_RESULT_FAIL;
776	else if (*wait_result == KFD_IOC_WAIT_RESULT_FAIL)
777		ret = -EIO;
778
779	return ret;
780}
781
782int kfd_event_mmap(struct kfd_process *p, struct vm_area_struct *vma)
783{
784	unsigned long pfn;
785	struct kfd_signal_page *page;
786	int ret;
787
788	/* check required size doesn't exceed the allocated size */
789	if (get_order(KFD_SIGNAL_EVENT_LIMIT * 8) <
790			get_order(vma->vm_end - vma->vm_start)) {
791		pr_err("Event page mmap requested illegal size\n");
792		return -EINVAL;
793	}
794
795	page = p->signal_page;
796	if (!page) {
797		/* Probably KFD bug, but mmap is user-accessible. */
798		pr_debug("Signal page could not be found\n");
799		return -EINVAL;
800	}
801
802	pfn = __pa(page->kernel_address);
803	pfn >>= PAGE_SHIFT;
804
805	vma->vm_flags |= VM_IO | VM_DONTCOPY | VM_DONTEXPAND | VM_NORESERVE
806		       | VM_DONTDUMP | VM_PFNMAP;
807
808	pr_debug("Mapping signal page\n");
809	pr_debug("     start user address  == 0x%08lx\n", vma->vm_start);
810	pr_debug("     end user address    == 0x%08lx\n", vma->vm_end);
811	pr_debug("     pfn                 == 0x%016lX\n", pfn);
812	pr_debug("     vm_flags            == 0x%08lX\n", vma->vm_flags);
813	pr_debug("     size                == 0x%08lX\n",
814			vma->vm_end - vma->vm_start);
815
816	page->user_address = (uint64_t __user *)vma->vm_start;
817
818	/* mapping the page to user process */
819	ret = remap_pfn_range(vma, vma->vm_start, pfn,
820			vma->vm_end - vma->vm_start, vma->vm_page_prot);
821	if (!ret)
822		p->signal_mapped_size = vma->vm_end - vma->vm_start;
823
824	return ret;
825}
826
827/*
828 * Assumes that p->event_mutex is held and of course
829 * that p is not going away (current or locked).
830 */
831static void lookup_events_by_type_and_signal(struct kfd_process *p,
832		int type, void *event_data)
833{
834	struct kfd_hsa_memory_exception_data *ev_data;
835	struct kfd_event *ev;
836	uint32_t id;
837	bool send_signal = true;
838
839	ev_data = (struct kfd_hsa_memory_exception_data *) event_data;
840
841	id = KFD_FIRST_NONSIGNAL_EVENT_ID;
842	idr_for_each_entry_continue(&p->event_idr, ev, id)
843		if (ev->type == type) {
844			send_signal = false;
845			dev_dbg(kfd_device,
846					"Event found: id %X type %d",
847					ev->event_id, ev->type);
848			set_event(ev);
849			if (ev->type == KFD_EVENT_TYPE_MEMORY && ev_data)
850				ev->memory_exception_data = *ev_data;
851		}
852
853	/* Send SIGTERM no event of type "type" has been found*/
854	if (send_signal) {
855		if (send_sigterm) {
856			dev_warn(kfd_device,
857				"Sending SIGTERM to HSA Process with PID %d ",
858					p->lead_thread->pid);
859			send_sig(SIGTERM, p->lead_thread, 0);
860		} else {
861			dev_err(kfd_device,
862				"HSA Process (PID %d) got unhandled exception",
863				p->lead_thread->pid);
864		}
865	}
866}
867
868#ifdef KFD_SUPPORT_IOMMU_V2
869void kfd_signal_iommu_event(struct kfd_dev *dev, unsigned int pasid,
870		unsigned long address, bool is_write_requested,
871		bool is_execute_requested)
872{
873	struct kfd_hsa_memory_exception_data memory_exception_data;
874	struct vm_area_struct *vma;
875
876	/*
877	 * Because we are called from arbitrary context (workqueue) as opposed
878	 * to process context, kfd_process could attempt to exit while we are
879	 * running so the lookup function increments the process ref count.
880	 */
881	struct kfd_process *p = kfd_lookup_process_by_pasid(pasid);
882	struct mm_struct *mm;
883
884	if (!p)
885		return; /* Presumably process exited. */
886
887	/* Take a safe reference to the mm_struct, which may otherwise
888	 * disappear even while the kfd_process is still referenced.
889	 */
890	mm = get_task_mm(p->lead_thread);
891	if (!mm) {
892		kfd_unref_process(p);
893		return; /* Process is exiting */
894	}
895
896	memset(&memory_exception_data, 0, sizeof(memory_exception_data));
897
898	down_read(&mm->mmap_sem);
899	vma = find_vma(mm, address);
900
901	memory_exception_data.gpu_id = dev->id;
902	memory_exception_data.va = address;
903	/* Set failure reason */
904	memory_exception_data.failure.NotPresent = 1;
905	memory_exception_data.failure.NoExecute = 0;
906	memory_exception_data.failure.ReadOnly = 0;
907	if (vma) {
908		if (vma->vm_start > address) {
909			memory_exception_data.failure.NotPresent = 1;
910			memory_exception_data.failure.NoExecute = 0;
911			memory_exception_data.failure.ReadOnly = 0;
912		} else {
913			memory_exception_data.failure.NotPresent = 0;
914			if (is_write_requested && !(vma->vm_flags & VM_WRITE))
915				memory_exception_data.failure.ReadOnly = 1;
916			else
917				memory_exception_data.failure.ReadOnly = 0;
918			if (is_execute_requested && !(vma->vm_flags & VM_EXEC))
919				memory_exception_data.failure.NoExecute = 1;
920			else
921				memory_exception_data.failure.NoExecute = 0;
922		}
923	}
924
925	up_read(&mm->mmap_sem);
926	mmput(mm);
927
928	mutex_lock(&p->event_mutex);
929
930	/* Lookup events by type and signal them */
931	lookup_events_by_type_and_signal(p, KFD_EVENT_TYPE_MEMORY,
932			&memory_exception_data);
933
934	mutex_unlock(&p->event_mutex);
935	kfd_unref_process(p);
936}
937#endif /* KFD_SUPPORT_IOMMU_V2 */
938
939void kfd_signal_hw_exception_event(unsigned int pasid)
940{
941	/*
942	 * Because we are called from arbitrary context (workqueue) as opposed
943	 * to process context, kfd_process could attempt to exit while we are
944	 * running so the lookup function increments the process ref count.
945	 */
946	struct kfd_process *p = kfd_lookup_process_by_pasid(pasid);
947
948	if (!p)
949		return; /* Presumably process exited. */
950
951	mutex_lock(&p->event_mutex);
952
953	/* Lookup events by type and signal them */
954	lookup_events_by_type_and_signal(p, KFD_EVENT_TYPE_HW_EXCEPTION, NULL);
955
956	mutex_unlock(&p->event_mutex);
957	kfd_unref_process(p);
958}