Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1038 insertions, 0 deletions

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_events.c b/drivers/gpu/drm/amd/amdkfd/kfd_events.c
new file mode 100644
index 000000000..892077377
--- /dev/null
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_events.c
@@ -0,0 +1,1038 @@
+/*
+ * Copyright 2014 Advanced Micro Devices, Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
+ * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#include <linux/mm_types.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/sched/signal.h>
+#include <linux/sched/mm.h>
+#include <linux/uaccess.h>
+#include <linux/mman.h>
+#include <linux/memory.h>
+#include "kfd_priv.h"
+#include "kfd_events.h"
+#include "kfd_iommu.h"
+#include <linux/device.h>
+
+/*
+ * Wrapper around wait_queue_entry_t
+ */
+struct kfd_event_waiter {
+	wait_queue_entry_t wait;
+	struct kfd_event *event; /* Event to wait for */
+	bool activated;		 /* Becomes true when event is signaled */
+};
+
+/*
+ * Each signal event needs a 64-bit signal slot where the signaler will write
+ * a 1 before sending an interrupt. (This is needed because some interrupts
+ * do not contain enough spare data bits to identify an event.)
+ * We get whole pages and map them to the process VA.
+ * Individual signal events use their event_id as slot index.
+ */
+struct kfd_signal_page {
+	uint64_t *kernel_address;
+	uint64_t __user *user_address;
+	bool need_to_free_pages;
+};
+
+
+static uint64_t *page_slots(struct kfd_signal_page *page)
+{
+	return page->kernel_address;
+}
+
+static struct kfd_signal_page *allocate_signal_page(struct kfd_process *p)
+{
+	void *backing_store;
+	struct kfd_signal_page *page;
+
+	page = kzalloc(sizeof(*page), GFP_KERNEL);
+	if (!page)
+		return NULL;
+
+	backing_store = (void *) __get_free_pages(GFP_KERNEL,
+					get_order(KFD_SIGNAL_EVENT_LIMIT * 8));
+	if (!backing_store)
+		goto fail_alloc_signal_store;
+
+	/* Initialize all events to unsignaled */
+	memset(backing_store, (uint8_t) UNSIGNALED_EVENT_SLOT,
+	       KFD_SIGNAL_EVENT_LIMIT * 8);
+
+	page->kernel_address = backing_store;
+	page->need_to_free_pages = true;
+	pr_debug("Allocated new event signal page at %p, for process %p\n",
+			page, p);
+
+	return page;
+
+fail_alloc_signal_store:
+	kfree(page);
+	return NULL;
+}
+
+static int allocate_event_notification_slot(struct kfd_process *p,
+					    struct kfd_event *ev)
+{
+	int id;
+
+	if (!p->signal_page) {
+		p->signal_page = allocate_signal_page(p);
+		if (!p->signal_page)
+			return -ENOMEM;
+		/* Oldest user mode expects 256 event slots */
+		p->signal_mapped_size = 256*8;
+	}
+
+	/*
+	 * Compatibility with old user mode: Only use signal slots
+	 * user mode has mapped, may be less than
+	 * KFD_SIGNAL_EVENT_LIMIT. This also allows future increase
+	 * of the event limit without breaking user mode.
+	 */
+	id = idr_alloc(&p->event_idr, ev, 0, p->signal_mapped_size / 8,
+		       GFP_KERNEL);
+	if (id < 0)
+		return id;
+
+	ev->event_id = id;
+	page_slots(p->signal_page)[id] = UNSIGNALED_EVENT_SLOT;
+
+	return 0;
+}
+
+/*
+ * Assumes that p->event_mutex is held and of course that p is not going
+ * away (current or locked).
+ */
+static struct kfd_event *lookup_event_by_id(struct kfd_process *p, uint32_t id)
+{
+	return idr_find(&p->event_idr, id);
+}
+
+/**
+ * lookup_signaled_event_by_partial_id - Lookup signaled event from partial ID
+ * @p:     Pointer to struct kfd_process
+ * @id:    ID to look up
+ * @bits:  Number of valid bits in @id
+ *
+ * Finds the first signaled event with a matching partial ID. If no
+ * matching signaled event is found, returns NULL. In that case the
+ * caller should assume that the partial ID is invalid and do an
+ * exhaustive search of all siglaned events.
+ *
+ * If multiple events with the same partial ID signal at the same
+ * time, they will be found one interrupt at a time, not necessarily
+ * in the same order the interrupts occurred. As long as the number of
+ * interrupts is correct, all signaled events will be seen by the
+ * driver.
+ */
+static struct kfd_event *lookup_signaled_event_by_partial_id(
+	struct kfd_process *p, uint32_t id, uint32_t bits)
+{
+	struct kfd_event *ev;
+
+	if (!p->signal_page || id >= KFD_SIGNAL_EVENT_LIMIT)
+		return NULL;
+
+	/* Fast path for the common case that @id is not a partial ID
+	 * and we only need a single lookup.
+	 */
+	if (bits > 31 || (1U << bits) >= KFD_SIGNAL_EVENT_LIMIT) {
+		if (page_slots(p->signal_page)[id] == UNSIGNALED_EVENT_SLOT)
+			return NULL;
+
+		return idr_find(&p->event_idr, id);
+	}
+
+	/* General case for partial IDs: Iterate over all matching IDs
+	 * and find the first one that has signaled.
+	 */
+	for (ev = NULL; id < KFD_SIGNAL_EVENT_LIMIT && !ev; id += 1U << bits) {
+		if (page_slots(p->signal_page)[id] == UNSIGNALED_EVENT_SLOT)
+			continue;
+
+		ev = idr_find(&p->event_idr, id);
+	}
+
+	return ev;
+}
+
+static int create_signal_event(struct file *devkfd,
+				struct kfd_process *p,
+				struct kfd_event *ev)
+{
+	int ret;
+
+	if (p->signal_mapped_size &&
+	    p->signal_event_count == p->signal_mapped_size / 8) {
+		if (!p->signal_event_limit_reached) {
+			pr_warn("Signal event wasn't created because limit was reached\n");
+			p->signal_event_limit_reached = true;
+		}
+		return -ENOSPC;
+	}
+
+	ret = allocate_event_notification_slot(p, ev);
+	if (ret) {
+		pr_warn("Signal event wasn't created because out of kernel memory\n");
+		return ret;
+	}
+
+	p->signal_event_count++;
+
+	ev->user_signal_address = &p->signal_page->user_address[ev->event_id];
+	pr_debug("Signal event number %zu created with id %d, address %p\n",
+			p->signal_event_count, ev->event_id,
+			ev->user_signal_address);
+
+	return 0;
+}
+
+static int create_other_event(struct kfd_process *p, struct kfd_event *ev)
+{
+	/* Cast KFD_LAST_NONSIGNAL_EVENT to uint32_t. This allows an
+	 * intentional integer overflow to -1 without a compiler
+	 * warning. idr_alloc treats a negative value as "maximum
+	 * signed integer".
+	 */
+	int id = idr_alloc(&p->event_idr, ev, KFD_FIRST_NONSIGNAL_EVENT_ID,
+			   (uint32_t)KFD_LAST_NONSIGNAL_EVENT_ID + 1,
+			   GFP_KERNEL);
+
+	if (id < 0)
+		return id;
+	ev->event_id = id;
+
+	return 0;
+}
+
+void kfd_event_init_process(struct kfd_process *p)
+{
+	mutex_init(&p->event_mutex);
+	idr_init(&p->event_idr);
+	p->signal_page = NULL;
+	p->signal_event_count = 0;
+}
+
+static void destroy_event(struct kfd_process *p, struct kfd_event *ev)
+{
+	struct kfd_event_waiter *waiter;
+
+	/* Wake up pending waiters. They will return failure */
+	list_for_each_entry(waiter, &ev->wq.head, wait.entry)
+		waiter->event = NULL;
+	wake_up_all(&ev->wq);
+
+	if (ev->type == KFD_EVENT_TYPE_SIGNAL ||
+	    ev->type == KFD_EVENT_TYPE_DEBUG)
+		p->signal_event_count--;
+
+	idr_remove(&p->event_idr, ev->event_id);
+	kfree(ev);
+}
+
+static void destroy_events(struct kfd_process *p)
+{
+	struct kfd_event *ev;
+	uint32_t id;
+
+	idr_for_each_entry(&p->event_idr, ev, id)
+		destroy_event(p, ev);
+	idr_destroy(&p->event_idr);
+}
+
+/*
+ * We assume that the process is being destroyed and there is no need to
+ * unmap the pages or keep bookkeeping data in order.
+ */
+static void shutdown_signal_page(struct kfd_process *p)
+{
+	struct kfd_signal_page *page = p->signal_page;
+
+	if (page) {
+		if (page->need_to_free_pages)
+			free_pages((unsigned long)page->kernel_address,
+				   get_order(KFD_SIGNAL_EVENT_LIMIT * 8));
+		kfree(page);
+	}
+}
+
+void kfd_event_free_process(struct kfd_process *p)
+{
+	destroy_events(p);
+	shutdown_signal_page(p);
+}
+
+static bool event_can_be_gpu_signaled(const struct kfd_event *ev)
+{
+	return ev->type == KFD_EVENT_TYPE_SIGNAL ||
+					ev->type == KFD_EVENT_TYPE_DEBUG;
+}
+
+static bool event_can_be_cpu_signaled(const struct kfd_event *ev)
+{
+	return ev->type == KFD_EVENT_TYPE_SIGNAL;
+}
+
+int kfd_event_page_set(struct kfd_process *p, void *kernel_address,
+		       uint64_t size)
+{
+	struct kfd_signal_page *page;
+
+	if (p->signal_page)
+		return -EBUSY;
+
+	page = kzalloc(sizeof(*page), GFP_KERNEL);
+	if (!page)
+		return -ENOMEM;
+
+	/* Initialize all events to unsignaled */
+	memset(kernel_address, (uint8_t) UNSIGNALED_EVENT_SLOT,
+	       KFD_SIGNAL_EVENT_LIMIT * 8);
+
+	page->kernel_address = kernel_address;
+
+	p->signal_page = page;
+	p->signal_mapped_size = size;
+
+	return 0;
+}
+
+int kfd_event_create(struct file *devkfd, struct kfd_process *p,
+		     uint32_t event_type, bool auto_reset, uint32_t node_id,
+		     uint32_t *event_id, uint32_t *event_trigger_data,
+		     uint64_t *event_page_offset, uint32_t *event_slot_index)
+{
+	int ret = 0;
+	struct kfd_event *ev = kzalloc(sizeof(*ev), GFP_KERNEL);
+
+	if (!ev)
+		return -ENOMEM;
+
+	ev->type = event_type;
+	ev->auto_reset = auto_reset;
+	ev->signaled = false;
+
+	init_waitqueue_head(&ev->wq);
+
+	*event_page_offset = 0;
+
+	mutex_lock(&p->event_mutex);
+
+	switch (event_type) {
+	case KFD_EVENT_TYPE_SIGNAL:
+	case KFD_EVENT_TYPE_DEBUG:
+		ret = create_signal_event(devkfd, p, ev);
+		if (!ret) {
+			*event_page_offset = KFD_MMAP_TYPE_EVENTS;
+			*event_page_offset <<= PAGE_SHIFT;
+			*event_slot_index = ev->event_id;
+		}
+		break;
+	default:
+		ret = create_other_event(p, ev);
+		break;
+	}
+
+	if (!ret) {
+		*event_id = ev->event_id;
+		*event_trigger_data = ev->event_id;
+	} else {
+		kfree(ev);
+	}
+
+	mutex_unlock(&p->event_mutex);
+
+	return ret;
+}
+
+/* Assumes that p is current. */
+int kfd_event_destroy(struct kfd_process *p, uint32_t event_id)
+{
+	struct kfd_event *ev;
+	int ret = 0;
+
+	mutex_lock(&p->event_mutex);
+
+	ev = lookup_event_by_id(p, event_id);
+
+	if (ev)
+		destroy_event(p, ev);
+	else
+		ret = -EINVAL;
+
+	mutex_unlock(&p->event_mutex);
+	return ret;
+}
+
+static void set_event(struct kfd_event *ev)
+{
+	struct kfd_event_waiter *waiter;
+
+	/* Auto reset if the list is non-empty and we're waking
+	 * someone. waitqueue_active is safe here because we're
+	 * protected by the p->event_mutex, which is also held when
+	 * updating the wait queues in kfd_wait_on_events.
+	 */
+	ev->signaled = !ev->auto_reset || !waitqueue_active(&ev->wq);
+
+	list_for_each_entry(waiter, &ev->wq.head, wait.entry)
+		waiter->activated = true;
+
+	wake_up_all(&ev->wq);
+}
+
+/* Assumes that p is current. */
+int kfd_set_event(struct kfd_process *p, uint32_t event_id)
+{
+	int ret = 0;
+	struct kfd_event *ev;
+
+	mutex_lock(&p->event_mutex);
+
+	ev = lookup_event_by_id(p, event_id);
+
+	if (ev && event_can_be_cpu_signaled(ev))
+		set_event(ev);
+	else
+		ret = -EINVAL;
+
+	mutex_unlock(&p->event_mutex);
+	return ret;
+}
+
+static void reset_event(struct kfd_event *ev)
+{
+	ev->signaled = false;
+}
+
+/* Assumes that p is current. */
+int kfd_reset_event(struct kfd_process *p, uint32_t event_id)
+{
+	int ret = 0;
+	struct kfd_event *ev;
+
+	mutex_lock(&p->event_mutex);
+
+	ev = lookup_event_by_id(p, event_id);
+
+	if (ev && event_can_be_cpu_signaled(ev))
+		reset_event(ev);
+	else
+		ret = -EINVAL;
+
+	mutex_unlock(&p->event_mutex);
+	return ret;
+
+}
+
+static void acknowledge_signal(struct kfd_process *p, struct kfd_event *ev)
+{
+	page_slots(p->signal_page)[ev->event_id] = UNSIGNALED_EVENT_SLOT;
+}
+
+static void set_event_from_interrupt(struct kfd_process *p,
+					struct kfd_event *ev)
+{
+	if (ev && event_can_be_gpu_signaled(ev)) {
+		acknowledge_signal(p, ev);
+		set_event(ev);
+	}
+}
+
+void kfd_signal_event_interrupt(unsigned int pasid, uint32_t partial_id,
+				uint32_t valid_id_bits)
+{
+	struct kfd_event *ev = NULL;
+
+	/*
+	 * Because we are called from arbitrary context (workqueue) as opposed
+	 * to process context, kfd_process could attempt to exit while we are
+	 * running so the lookup function increments the process ref count.
+	 */
+	struct kfd_process *p = kfd_lookup_process_by_pasid(pasid);
+
+	if (!p)
+		return; /* Presumably process exited. */
+
+	mutex_lock(&p->event_mutex);
+
+	if (valid_id_bits)
+		ev = lookup_signaled_event_by_partial_id(p, partial_id,
+							 valid_id_bits);
+	if (ev) {
+		set_event_from_interrupt(p, ev);
+	} else if (p->signal_page) {
+		/*
+		 * Partial ID lookup failed. Assume that the event ID
+		 * in the interrupt payload was invalid and do an
+		 * exhaustive search of signaled events.
+		 */
+		uint64_t *slots = page_slots(p->signal_page);
+		uint32_t id;
+
+		if (valid_id_bits)
+			pr_debug_ratelimited("Partial ID invalid: %u (%u valid bits)\n",
+					     partial_id, valid_id_bits);
+
+		if (p->signal_event_count < KFD_SIGNAL_EVENT_LIMIT / 64) {
+			/* With relatively few events, it's faster to
+			 * iterate over the event IDR
+			 */
+			idr_for_each_entry(&p->event_idr, ev, id) {
+				if (id >= KFD_SIGNAL_EVENT_LIMIT)
+					break;
+
+				if (slots[id] != UNSIGNALED_EVENT_SLOT)
+					set_event_from_interrupt(p, ev);
+			}
+		} else {
+			/* With relatively many events, it's faster to
+			 * iterate over the signal slots and lookup
+			 * only signaled events from the IDR.
+			 */
+			for (id = 0; id < KFD_SIGNAL_EVENT_LIMIT; id++)
+				if (slots[id] != UNSIGNALED_EVENT_SLOT) {
+					ev = lookup_event_by_id(p, id);
+					set_event_from_interrupt(p, ev);
+				}
+		}
+	}
+
+	mutex_unlock(&p->event_mutex);
+	kfd_unref_process(p);
+}
+
+static struct kfd_event_waiter *alloc_event_waiters(uint32_t num_events)
+{
+	struct kfd_event_waiter *event_waiters;
+	uint32_t i;
+
+	event_waiters = kmalloc_array(num_events,
+					sizeof(struct kfd_event_waiter),
+					GFP_KERNEL);
+	if (!event_waiters)
+		return NULL;
+
+	for (i = 0; (event_waiters) && (i < num_events) ; i++) {
+		init_wait(&event_waiters[i].wait);
+		event_waiters[i].activated = false;
+	}
+
+	return event_waiters;
+}
+
+static int init_event_waiter_get_status(struct kfd_process *p,
+		struct kfd_event_waiter *waiter,
+		uint32_t event_id)
+{
+	struct kfd_event *ev = lookup_event_by_id(p, event_id);
+
+	if (!ev)
+		return -EINVAL;
+
+	waiter->event = ev;
+	waiter->activated = ev->signaled;
+	ev->signaled = ev->signaled && !ev->auto_reset;
+
+	return 0;
+}
+
+static void init_event_waiter_add_to_waitlist(struct kfd_event_waiter *waiter)
+{
+	struct kfd_event *ev = waiter->event;
+
+	/* Only add to the wait list if we actually need to
+	 * wait on this event.
+	 */
+	if (!waiter->activated)
+		add_wait_queue(&ev->wq, &waiter->wait);
+}
+
+/* test_event_condition - Test condition of events being waited for
+ * @all:           Return completion only if all events have signaled
+ * @num_events:    Number of events to wait for
+ * @event_waiters: Array of event waiters, one per event
+ *
+ * Returns KFD_IOC_WAIT_RESULT_COMPLETE if all (or one) event(s) have
+ * signaled. Returns KFD_IOC_WAIT_RESULT_TIMEOUT if no (or not all)
+ * events have signaled. Returns KFD_IOC_WAIT_RESULT_FAIL if any of
+ * the events have been destroyed.
+ */
+static uint32_t test_event_condition(bool all, uint32_t num_events,
+				struct kfd_event_waiter *event_waiters)
+{
+	uint32_t i;
+	uint32_t activated_count = 0;
+
+	for (i = 0; i < num_events; i++) {
+		if (!event_waiters[i].event)
+			return KFD_IOC_WAIT_RESULT_FAIL;
+
+		if (event_waiters[i].activated) {
+			if (!all)
+				return KFD_IOC_WAIT_RESULT_COMPLETE;
+
+			activated_count++;
+		}
+	}
+
+	return activated_count == num_events ?
+		KFD_IOC_WAIT_RESULT_COMPLETE : KFD_IOC_WAIT_RESULT_TIMEOUT;
+}
+
+/*
+ * Copy event specific data, if defined.
+ * Currently only memory exception events have additional data to copy to user
+ */
+static int copy_signaled_event_data(uint32_t num_events,
+		struct kfd_event_waiter *event_waiters,
+		struct kfd_event_data __user *data)
+{
+	struct kfd_hsa_memory_exception_data *src;
+	struct kfd_hsa_memory_exception_data __user *dst;
+	struct kfd_event_waiter *waiter;
+	struct kfd_event *event;
+	uint32_t i;
+
+	for (i = 0; i < num_events; i++) {
+		waiter = &event_waiters[i];
+		event = waiter->event;
+		if (waiter->activated && event->type == KFD_EVENT_TYPE_MEMORY) {
+			dst = &data[i].memory_exception_data;
+			src = &event->memory_exception_data;
+			if (copy_to_user(dst, src,
+				sizeof(struct kfd_hsa_memory_exception_data)))
+				return -EFAULT;
+		}
+	}
+
+	return 0;
+
+}
+
+
+
+static long user_timeout_to_jiffies(uint32_t user_timeout_ms)
+{
+	if (user_timeout_ms == KFD_EVENT_TIMEOUT_IMMEDIATE)
+		return 0;
+
+	if (user_timeout_ms == KFD_EVENT_TIMEOUT_INFINITE)
+		return MAX_SCHEDULE_TIMEOUT;
+
+	/*
+	 * msecs_to_jiffies interprets all values above 2^31-1 as infinite,
+	 * but we consider them finite.
+	 * This hack is wrong, but nobody is likely to notice.
+	 */
+	user_timeout_ms = min_t(uint32_t, user_timeout_ms, 0x7FFFFFFF);
+
+	return msecs_to_jiffies(user_timeout_ms) + 1;
+}
+
+static void free_waiters(uint32_t num_events, struct kfd_event_waiter *waiters)
+{
+	uint32_t i;
+
+	for (i = 0; i < num_events; i++)
+		if (waiters[i].event)
+			remove_wait_queue(&waiters[i].event->wq,
+					  &waiters[i].wait);
+
+	kfree(waiters);
+}
+
+int kfd_wait_on_events(struct kfd_process *p,
+		       uint32_t num_events, void __user *data,
+		       bool all, uint32_t user_timeout_ms,
+		       uint32_t *wait_result)
+{
+	struct kfd_event_data __user *events =
+			(struct kfd_event_data __user *) data;
+	uint32_t i;
+	int ret = 0;
+
+	struct kfd_event_waiter *event_waiters = NULL;
+	long timeout = user_timeout_to_jiffies(user_timeout_ms);
+
+	event_waiters = alloc_event_waiters(num_events);
+	if (!event_waiters) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	mutex_lock(&p->event_mutex);
+
+	for (i = 0; i < num_events; i++) {
+		struct kfd_event_data event_data;
+
+		if (copy_from_user(&event_data, &events[i],
+				sizeof(struct kfd_event_data))) {
+			ret = -EFAULT;
+			goto out_unlock;
+		}
+
+		ret = init_event_waiter_get_status(p, &event_waiters[i],
+				event_data.event_id);
+		if (ret)
+			goto out_unlock;
+	}
+
+	/* Check condition once. */
+	*wait_result = test_event_condition(all, num_events, event_waiters);
+	if (*wait_result == KFD_IOC_WAIT_RESULT_COMPLETE) {
+		ret = copy_signaled_event_data(num_events,
+					       event_waiters, events);
+		goto out_unlock;
+	} else if (WARN_ON(*wait_result == KFD_IOC_WAIT_RESULT_FAIL)) {
+		/* This should not happen. Events shouldn't be
+		 * destroyed while we're holding the event_mutex
+		 */
+		goto out_unlock;
+	}
+
+	/* Add to wait lists if we need to wait. */
+	for (i = 0; i < num_events; i++)
+		init_event_waiter_add_to_waitlist(&event_waiters[i]);
+
+	mutex_unlock(&p->event_mutex);
+
+	while (true) {
+		if (fatal_signal_pending(current)) {
+			ret = -EINTR;
+			break;
+		}
+
+		if (signal_pending(current)) {
+			/*
+			 * This is wrong when a nonzero, non-infinite timeout
+			 * is specified. We need to use
+			 * ERESTARTSYS_RESTARTBLOCK, but struct restart_block
+			 * contains a union with data for each user and it's
+			 * in generic kernel code that I don't want to
+			 * touch yet.
+			 */
+			ret = -ERESTARTSYS;
+			break;
+		}
+
+		/* Set task state to interruptible sleep before
+		 * checking wake-up conditions. A concurrent wake-up
+		 * will put the task back into runnable state. In that
+		 * case schedule_timeout will not put the task to
+		 * sleep and we'll get a chance to re-check the
+		 * updated conditions almost immediately. Otherwise,
+		 * this race condition would lead to a soft hang or a
+		 * very long sleep.
+		 */
+		set_current_state(TASK_INTERRUPTIBLE);
+
+		*wait_result = test_event_condition(all, num_events,
+						    event_waiters);
+		if (*wait_result != KFD_IOC_WAIT_RESULT_TIMEOUT)
+			break;
+
+		if (timeout <= 0)
+			break;
+
+		timeout = schedule_timeout(timeout);
+	}
+	__set_current_state(TASK_RUNNING);
+
+	/* copy_signaled_event_data may sleep. So this has to happen
+	 * after the task state is set back to RUNNING.
+	 */
+	if (!ret && *wait_result == KFD_IOC_WAIT_RESULT_COMPLETE)
+		ret = copy_signaled_event_data(num_events,
+					       event_waiters, events);
+
+	mutex_lock(&p->event_mutex);
+out_unlock:
+	free_waiters(num_events, event_waiters);
+	mutex_unlock(&p->event_mutex);
+out:
+	if (ret)
+		*wait_result = KFD_IOC_WAIT_RESULT_FAIL;
+	else if (*wait_result == KFD_IOC_WAIT_RESULT_FAIL)
+		ret = -EIO;
+
+	return ret;
+}
+
+int kfd_event_mmap(struct kfd_process *p, struct vm_area_struct *vma)
+{
+	unsigned long pfn;
+	struct kfd_signal_page *page;
+	int ret;
+
+	/* check required size doesn't exceed the allocated size */
+	if (get_order(KFD_SIGNAL_EVENT_LIMIT * 8) <
+			get_order(vma->vm_end - vma->vm_start)) {
+		pr_err("Event page mmap requested illegal size\n");
+		return -EINVAL;
+	}
+
+	page = p->signal_page;
+	if (!page) {
+		/* Probably KFD bug, but mmap is user-accessible. */
+		pr_debug("Signal page could not be found\n");
+		return -EINVAL;
+	}
+
+	pfn = __pa(page->kernel_address);
+	pfn >>= PAGE_SHIFT;
+
+	vma->vm_flags |= VM_IO | VM_DONTCOPY | VM_DONTEXPAND | VM_NORESERVE
+		       | VM_DONTDUMP | VM_PFNMAP;
+
+	pr_debug("Mapping signal page\n");
+	pr_debug("     start user address  == 0x%08lx\n", vma->vm_start);
+	pr_debug("     end user address    == 0x%08lx\n", vma->vm_end);
+	pr_debug("     pfn                 == 0x%016lX\n", pfn);
+	pr_debug("     vm_flags            == 0x%08lX\n", vma->vm_flags);
+	pr_debug("     size                == 0x%08lX\n",
+			vma->vm_end - vma->vm_start);
+
+	page->user_address = (uint64_t __user *)vma->vm_start;
+
+	/* mapping the page to user process */
+	ret = remap_pfn_range(vma, vma->vm_start, pfn,
+			vma->vm_end - vma->vm_start, vma->vm_page_prot);
+	if (!ret)
+		p->signal_mapped_size = vma->vm_end - vma->vm_start;
+
+	return ret;
+}
+
+/*
+ * Assumes that p->event_mutex is held and of course
+ * that p is not going away (current or locked).
+ */
+static void lookup_events_by_type_and_signal(struct kfd_process *p,
+		int type, void *event_data)
+{
+	struct kfd_hsa_memory_exception_data *ev_data;
+	struct kfd_event *ev;
+	uint32_t id;
+	bool send_signal = true;
+
+	ev_data = (struct kfd_hsa_memory_exception_data *) event_data;
+
+	id = KFD_FIRST_NONSIGNAL_EVENT_ID;
+	idr_for_each_entry_continue(&p->event_idr, ev, id)
+		if (ev->type == type) {
+			send_signal = false;
+			dev_dbg(kfd_device,
+					"Event found: id %X type %d",
+					ev->event_id, ev->type);
+			set_event(ev);
+			if (ev->type == KFD_EVENT_TYPE_MEMORY && ev_data)
+				ev->memory_exception_data = *ev_data;
+		}
+
+	if (type == KFD_EVENT_TYPE_MEMORY) {
+		dev_warn(kfd_device,
+			"Sending SIGSEGV to HSA Process with PID %d ",
+				p->lead_thread->pid);
+		send_sig(SIGSEGV, p->lead_thread, 0);
+	}
+
+	/* Send SIGTERM no event of type "type" has been found*/
+	if (send_signal) {
+		if (send_sigterm) {
+			dev_warn(kfd_device,
+				"Sending SIGTERM to HSA Process with PID %d ",
+					p->lead_thread->pid);
+			send_sig(SIGTERM, p->lead_thread, 0);
+		} else {
+			dev_err(kfd_device,
+				"HSA Process (PID %d) got unhandled exception",
+				p->lead_thread->pid);
+		}
+	}
+}
+
+#ifdef KFD_SUPPORT_IOMMU_V2
+void kfd_signal_iommu_event(struct kfd_dev *dev, unsigned int pasid,
+		unsigned long address, bool is_write_requested,
+		bool is_execute_requested)
+{
+	struct kfd_hsa_memory_exception_data memory_exception_data;
+	struct vm_area_struct *vma;
+
+	/*
+	 * Because we are called from arbitrary context (workqueue) as opposed
+	 * to process context, kfd_process could attempt to exit while we are
+	 * running so the lookup function increments the process ref count.
+	 */
+	struct kfd_process *p = kfd_lookup_process_by_pasid(pasid);
+	struct mm_struct *mm;
+
+	if (!p)
+		return; /* Presumably process exited. */
+
+	/* Take a safe reference to the mm_struct, which may otherwise
+	 * disappear even while the kfd_process is still referenced.
+	 */
+	mm = get_task_mm(p->lead_thread);
+	if (!mm) {
+		kfd_unref_process(p);
+		return; /* Process is exiting */
+	}
+
+	memset(&memory_exception_data, 0, sizeof(memory_exception_data));
+
+	down_read(&mm->mmap_sem);
+	vma = find_vma(mm, address);
+
+	memory_exception_data.gpu_id = dev->id;
+	memory_exception_data.va = address;
+	/* Set failure reason */
+	memory_exception_data.failure.NotPresent = 1;
+	memory_exception_data.failure.NoExecute = 0;
+	memory_exception_data.failure.ReadOnly = 0;
+	if (vma && address >= vma->vm_start) {
+		memory_exception_data.failure.NotPresent = 0;
+
+		if (is_write_requested && !(vma->vm_flags & VM_WRITE))
+			memory_exception_data.failure.ReadOnly = 1;
+		else
+			memory_exception_data.failure.ReadOnly = 0;
+
+		if (is_execute_requested && !(vma->vm_flags & VM_EXEC))
+			memory_exception_data.failure.NoExecute = 1;
+		else
+			memory_exception_data.failure.NoExecute = 0;
+	}
+
+	up_read(&mm->mmap_sem);
+	mmput(mm);
+
+	pr_debug("notpresent %d, noexecute %d, readonly %d\n",
+			memory_exception_data.failure.NotPresent,
+			memory_exception_data.failure.NoExecute,
+			memory_exception_data.failure.ReadOnly);
+
+	/* Workaround on Raven to not kill the process when memory is freed
+	 * before IOMMU is able to finish processing all the excessive PPRs
+	 */
+	if (dev->device_info->asic_family != CHIP_RAVEN) {
+		mutex_lock(&p->event_mutex);
+
+		/* Lookup events by type and signal them */
+		lookup_events_by_type_and_signal(p, KFD_EVENT_TYPE_MEMORY,
+				&memory_exception_data);
+
+		mutex_unlock(&p->event_mutex);
+	}
+
+	kfd_unref_process(p);
+}
+#endif /* KFD_SUPPORT_IOMMU_V2 */
+
+void kfd_signal_hw_exception_event(unsigned int pasid)
+{
+	/*
+	 * Because we are called from arbitrary context (workqueue) as opposed
+	 * to process context, kfd_process could attempt to exit while we are
+	 * running so the lookup function increments the process ref count.
+	 */
+	struct kfd_process *p = kfd_lookup_process_by_pasid(pasid);
+
+	if (!p)
+		return; /* Presumably process exited. */
+
+	mutex_lock(&p->event_mutex);
+
+	/* Lookup events by type and signal them */
+	lookup_events_by_type_and_signal(p, KFD_EVENT_TYPE_HW_EXCEPTION, NULL);
+
+	mutex_unlock(&p->event_mutex);
+	kfd_unref_process(p);
+}
+
+void kfd_signal_vm_fault_event(struct kfd_dev *dev, unsigned int pasid,
+				struct kfd_vm_fault_info *info)
+{
+	struct kfd_event *ev;
+	uint32_t id;
+	struct kfd_process *p = kfd_lookup_process_by_pasid(pasid);
+	struct kfd_hsa_memory_exception_data memory_exception_data;
+
+	if (!p)
+		return; /* Presumably process exited. */
+	memset(&memory_exception_data, 0, sizeof(memory_exception_data));
+	memory_exception_data.gpu_id = dev->id;
+	memory_exception_data.failure.imprecise = 1;
+	/* Set failure reason */
+	if (info) {
+		memory_exception_data.va = (info->page_addr) << PAGE_SHIFT;
+		memory_exception_data.failure.NotPresent =
+			info->prot_valid ? 1 : 0;
+		memory_exception_data.failure.NoExecute =
+			info->prot_exec ? 1 : 0;
+		memory_exception_data.failure.ReadOnly =
+			info->prot_write ? 1 : 0;
+		memory_exception_data.failure.imprecise = 0;
+	}
+	mutex_lock(&p->event_mutex);
+
+	id = KFD_FIRST_NONSIGNAL_EVENT_ID;
+	idr_for_each_entry_continue(&p->event_idr, ev, id)
+		if (ev->type == KFD_EVENT_TYPE_MEMORY) {
+			ev->memory_exception_data = memory_exception_data;
+			set_event(ev);
+		}
+
+	mutex_unlock(&p->event_mutex);
+	kfd_unref_process(p);
+}
+
+void kfd_signal_reset_event(struct kfd_dev *dev)
+{
+	struct kfd_hsa_hw_exception_data hw_exception_data;
+	struct kfd_process *p;
+	struct kfd_event *ev;
+	unsigned int temp;
+	uint32_t id, idx;
+
+	/* Whole gpu reset caused by GPU hang and memory is lost */
+	memset(&hw_exception_data, 0, sizeof(hw_exception_data));
+	hw_exception_data.gpu_id = dev->id;
+	hw_exception_data.memory_lost = 1;
+
+	idx = srcu_read_lock(&kfd_processes_srcu);
+	hash_for_each_rcu(kfd_processes_table, temp, p, kfd_processes) {
+		mutex_lock(&p->event_mutex);
+		id = KFD_FIRST_NONSIGNAL_EVENT_ID;
+		idr_for_each_entry_continue(&p->event_idr, ev, id)
+			if (ev->type == KFD_EVENT_TYPE_HW_EXCEPTION) {
+				ev->hw_exception_data = hw_exception_data;
+				set_event(ev);
+			}
+		mutex_unlock(&p->event_mutex);
+	}
+	srcu_read_unlock(&kfd_processes_srcu, idx);
+}