drm/amdkfd: Add the events module

This patch adds the events module (kfd_events.c) and the interrupt
handle module for Kaveri (cik_event_interrupt.c).

The patch updates the interrupt_is_wanted(), so that it now calls the
interrupt isr function specific for the device that received the
interrupt. That function(implemented in cik_event_interrupt.c)
returns whether this interrupt is of interest to us or not.

The patch also updates the interrupt_wq(), so that it now calls the
device's specific wq function, which checks the interrupt source
and tries to signal relevant events.

v2:

Increase limit of signal events to 4096 per process
Remove bitfields from struct cik_ih_ring_entry
Rename radeon_kfd_event_mmap to kfd_event_mmap
Add debug prints to allocate_free_slot and allocate_signal_page
Make allocate_event_notification_slot return a correct value
Add warning prints to create_signal_event
Remove error print from IOCTL path
Reformatted debug prints in kfd_event_mmap
Map correct size (as received from mmap) in kfd_event_mmap

v3:

Reduce limit of signal events back to 256 per process
Fix allocation of kernel memory for signal events

Signed-off-by: Andrew Lewycky <[e-mail]>
Signed-off-by: Oded Gabbay <[e-mail]>

drivers/gpu/drm/amd/amdkfd/Makefile

···
 		kfd_kernel_queue_vi.o kfd_packet_manager.o \
 		kfd_process_queue_manager.o kfd_device_queue_manager.o \
 		kfd_device_queue_manager_cik.o kfd_device_queue_manager_vi.o \
-		kfd_interrupt.o
+		kfd_interrupt.o kfd_events.o cik_event_interrupt.o
 
 obj-$(CONFIG_HSA_AMD)	+= amdkfd.o

drivers/gpu/drm/amd/amdkfd/cik_event_interrupt.c

···
+/*
+ * 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 "kfd_priv.h"
+#include "kfd_events.h"
+#include "cik_int.h"
+
+static bool cik_event_interrupt_isr(struct kfd_dev *dev,
+					const uint32_t *ih_ring_entry)
+{
+	unsigned int pasid;
+	const struct cik_ih_ring_entry *ihre =
+			(const struct cik_ih_ring_entry *)ih_ring_entry;
+
+	pasid = (ihre->ring_id & 0xffff0000) >> 16;
+
+	/* Do not process in ISR, just request it to be forwarded to WQ. */
+	return (pasid != 0) &&
+		(ihre->source_id == CIK_INTSRC_CP_END_OF_PIPE ||
+		ihre->source_id == CIK_INTSRC_SQ_INTERRUPT_MSG);
+}
+
+static void cik_event_interrupt_wq(struct kfd_dev *dev,
+					const uint32_t *ih_ring_entry)
+{
+	unsigned int pasid;
+	const struct cik_ih_ring_entry *ihre =
+			(const struct cik_ih_ring_entry *)ih_ring_entry;
+
+	pasid = (ihre->ring_id & 0xffff0000) >> 16;
+
+	if (pasid == 0)
+		return;
+
+	if (ihre->source_id == CIK_INTSRC_CP_END_OF_PIPE)
+		kfd_signal_event_interrupt(pasid, 0, 0);
+	else if (ihre->source_id == CIK_INTSRC_SQ_INTERRUPT_MSG)
+		kfd_signal_event_interrupt(pasid, ihre->data & 0xFF, 8);
+}
+
+const struct kfd_event_interrupt_class event_interrupt_class_cik = {
+	.interrupt_isr = cik_event_interrupt_isr,
+	.interrupt_wq = cik_event_interrupt_wq,
+};

drivers/gpu/drm/amd/amdkfd/cik_int.h

···
+/*
+ * 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.
+ */
+
+#ifndef HSA_RADEON_CIK_INT_H_INCLUDED
+#define HSA_RADEON_CIK_INT_H_INCLUDED
+
+#include <linux/types.h>
+
+struct cik_ih_ring_entry {
+	uint32_t source_id;
+	uint32_t data;
+	uint32_t ring_id;
+	uint32_t reserved;
+};
+
+#define CIK_INTSRC_DEQUEUE_COMPLETE	0xC6
+#define CIK_INTSRC_CP_END_OF_PIPE	0xB5
+#define CIK_INTSRC_SQ_INTERRUPT_MSG	0xEF
+
+#endif
+

drivers/gpu/drm/amd/amdkfd/kfd_chardev.c

···
 
 	args->queue_id = queue_id;
 
+
 	/* Return gpu_id as doorbell offset for mmap usage */
-	args->doorbell_offset = args->gpu_id << PAGE_SHIFT;
+	args->doorbell_offset = (KFD_MMAP_DOORBELL_MASK | args->gpu_id);
+	args->doorbell_offset <<= PAGE_SHIFT;
 
 	mutex_unlock(&p->mutex);
 
···
 	if (IS_ERR(process))
 		return PTR_ERR(process);
 
-	return kfd_doorbell_mmap(process, vma);
+	if ((vma->vm_pgoff & KFD_MMAP_DOORBELL_MASK) ==
+			KFD_MMAP_DOORBELL_MASK) {
+		vma->vm_pgoff = vma->vm_pgoff ^ KFD_MMAP_DOORBELL_MASK;
+		return kfd_doorbell_mmap(process, vma);
+	} else if ((vma->vm_pgoff & KFD_MMAP_EVENTS_MASK) ==
+			KFD_MMAP_EVENTS_MASK) {
+		vma->vm_pgoff = vma->vm_pgoff ^ KFD_MMAP_EVENTS_MASK;
+		return kfd_event_mmap(process, vma);
+	}
+
+	return -EFAULT;
 }

drivers/gpu/drm/amd/amdkfd/kfd_device.c

···
 	.asic_family = CHIP_KAVERI,
 	.max_pasid_bits = 16,
 	.ih_ring_entry_size = 4 * sizeof(uint32_t),
+	.event_interrupt_class = &event_interrupt_class_cik,
 	.mqd_size_aligned = MQD_SIZE_ALIGNED
 };
 

drivers/gpu/drm/amd/amdkfd/kfd_events.c

···
+/*
+ * 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.h>
+#include <linux/uaccess.h>
+#include <linux/mm.h>
+#include <linux/mman.h>
+#include <linux/memory.h>
+#include "kfd_priv.h"
+#include "kfd_events.h"
+
+/*
+ * A task can only be on a single wait_queue at a time, but we need to support
+ * waiting on multiple events (any/all).
+ * Instead of each event simply having a wait_queue with sleeping tasks, it
+ * has a singly-linked list of tasks.
+ * A thread that wants to sleep creates an array of these, one for each event
+ * and adds one to each event's waiter chain.
+ */
+struct kfd_event_waiter {
+	struct list_head waiters;
+	struct task_struct *sleeping_task;
+
+	/* Transitions to true when the event this belongs to is signaled. */
+	bool activated;
+};
+
+/*
+ * Over-complicated pooled allocator for event notification slots.
+ *
+ * Each signal event needs a 64-bit signal slot where the signaler will write
+ * a 1 before sending an interrupt.l (This is needed because some interrupts
+ * do not contain enough spare data bits to identify an event.)
+ * We get whole pages from vmalloc and map them to the process VA.
+ * Individual signal events are then allocated a slot in a page.
+ */
+
+struct signal_page {
+	struct list_head event_pages;	/* kfd_process.signal_event_pages */
+	uint64_t *kernel_address;
+	uint64_t __user *user_address;
+	uint32_t page_index;		/* Index into the mmap aperture. */
+	unsigned int free_slots;
+	unsigned long used_slot_bitmap[0];
+};
+
+#define SLOTS_PER_PAGE KFD_SIGNAL_EVENT_LIMIT
+#define SLOT_BITMAP_SIZE BITS_TO_LONGS(SLOTS_PER_PAGE)
+#define BITS_PER_PAGE (ilog2(SLOTS_PER_PAGE)+1)
+#define SIGNAL_PAGE_SIZE (sizeof(struct signal_page) + \
+				SLOT_BITMAP_SIZE * sizeof(long))
+
+/*
+ * For signal events, the event ID is used as the interrupt user data.
+ * For SQ s_sendmsg interrupts, this is limited to 8 bits.
+ */
+
+#define INTERRUPT_DATA_BITS 8
+#define SIGNAL_EVENT_ID_SLOT_SHIFT 0
+
+static uint64_t *page_slots(struct signal_page *page)
+{
+	return page->kernel_address;
+}
+
+static bool allocate_free_slot(struct kfd_process *process,
+				struct signal_page **out_page,
+				unsigned int *out_slot_index)
+{
+	struct signal_page *page;
+
+	list_for_each_entry(page, &process->signal_event_pages, event_pages) {
+		if (page->free_slots > 0) {
+			unsigned int slot =
+				find_first_zero_bit(page->used_slot_bitmap,
+							SLOTS_PER_PAGE);
+
+			__set_bit(slot, page->used_slot_bitmap);
+			page->free_slots--;
+
+			page_slots(page)[slot] = UNSIGNALED_EVENT_SLOT;
+
+			*out_page = page;
+			*out_slot_index = slot;
+
+			pr_debug("allocated event signal slot in page %p, slot %d\n",
+					page, slot);
+
+			return true;
+		}
+	}
+
+	pr_debug("No free event signal slots were found for process %p\n",
+			process);
+
+	return false;
+}
+
+#define list_tail_entry(head, type, member) \
+	list_entry((head)->prev, type, member)
+
+static bool allocate_signal_page(struct file *devkfd, struct kfd_process *p)
+{
+	void *backing_store;
+	struct signal_page *page;
+
+	page = kzalloc(SIGNAL_PAGE_SIZE, GFP_KERNEL);
+	if (!page)
+		goto fail_alloc_signal_page;
+
+	page->free_slots = SLOTS_PER_PAGE;
+
+	backing_store = (void *) __get_free_pages(GFP_KERNEL | __GFP_ZERO,
+					get_order(KFD_SIGNAL_EVENT_LIMIT * 8));
+	if (!backing_store)
+		goto fail_alloc_signal_store;
+
+	/* prevent user-mode info leaks */
+	memset(backing_store, (uint8_t) UNSIGNALED_EVENT_SLOT,
+		KFD_SIGNAL_EVENT_LIMIT * 8);
+
+	page->kernel_address = backing_store;
+
+	if (list_empty(&p->signal_event_pages))
+		page->page_index = 0;
+	else
+		page->page_index = list_tail_entry(&p->signal_event_pages,
+						   struct signal_page,
+						   event_pages)->page_index + 1;
+
+	pr_debug("allocated new event signal page at %p, for process %p\n",
+			page, p);
+	pr_debug("page index is %d\n", page->page_index);
+
+	list_add(&page->event_pages, &p->signal_event_pages);
+
+	return true;
+
+fail_alloc_signal_store:
+	kfree(page);
+fail_alloc_signal_page:
+	return false;
+}
+
+static bool allocate_event_notification_slot(struct file *devkfd,
+					struct kfd_process *p,
+					struct signal_page **page,
+					unsigned int *signal_slot_index)
+{
+	bool ret;
+
+	ret = allocate_free_slot(p, page, signal_slot_index);
+	if (ret == false) {
+		ret = allocate_signal_page(devkfd, p);
+		if (ret == true)
+			ret = allocate_free_slot(p, page, signal_slot_index);
+	}
+
+	return ret;
+}
+
+/* Assumes that the process's event_mutex is locked. */
+static void release_event_notification_slot(struct signal_page *page,
+						size_t slot_index)
+{
+	__clear_bit(slot_index, page->used_slot_bitmap);
+	page->free_slots++;
+
+	/* We don't free signal pages, they are retained by the process
+	 * and reused until it exits. */
+}
+
+static struct signal_page *lookup_signal_page_by_index(struct kfd_process *p,
+						unsigned int page_index)
+{
+	struct signal_page *page;
+
+	/*
+	 * This is safe because we don't delete signal pages until the
+	 * process exits.
+	 */
+	list_for_each_entry(page, &p->signal_event_pages, event_pages)
+		if (page->page_index == page_index)
+			return page;
+
+	return NULL;
+}
+
+/*
+ * 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)
+{
+	struct kfd_event *ev;
+
+	hash_for_each_possible(p->events, ev, events, id)
+		if (ev->event_id == id)
+			return ev;
+
+	return NULL;
+}
+
+static u32 make_signal_event_id(struct signal_page *page,
+					 unsigned int signal_slot_index)
+{
+	return page->page_index |
+			(signal_slot_index << SIGNAL_EVENT_ID_SLOT_SHIFT);
+}
+
+/*
+ * Produce a kfd event id for a nonsignal event.
+ * These are arbitrary numbers, so we do a sequential search through
+ * the hash table for an unused number.
+ */
+static u32 make_nonsignal_event_id(struct kfd_process *p)
+{
+	u32 id;
+
+	for (id = p->next_nonsignal_event_id;
+		id < KFD_LAST_NONSIGNAL_EVENT_ID &&
+		lookup_event_by_id(p, id) != NULL;
+		id++)
+		;
+
+	if (id < KFD_LAST_NONSIGNAL_EVENT_ID) {
+
+		/*
+		 * What if id == LAST_NONSIGNAL_EVENT_ID - 1?
+		 * Then next_nonsignal_event_id = LAST_NONSIGNAL_EVENT_ID so
+		 * the first loop fails immediately and we proceed with the
+		 * wraparound loop below.
+		 */
+		p->next_nonsignal_event_id = id + 1;
+
+		return id;
+	}
+
+	for (id = KFD_FIRST_NONSIGNAL_EVENT_ID;
+		id < KFD_LAST_NONSIGNAL_EVENT_ID &&
+		lookup_event_by_id(p, id) != NULL;
+		id++)
+		;
+
+
+	if (id < KFD_LAST_NONSIGNAL_EVENT_ID) {
+		p->next_nonsignal_event_id = id + 1;
+		return id;
+	}
+
+	p->next_nonsignal_event_id = KFD_FIRST_NONSIGNAL_EVENT_ID;
+	return 0;
+}
+
+static struct kfd_event *lookup_event_by_page_slot(struct kfd_process *p,
+						struct signal_page *page,
+						unsigned int signal_slot)
+{
+	return lookup_event_by_id(p, make_signal_event_id(page, signal_slot));
+}
+
+static int create_signal_event(struct file *devkfd,
+				struct kfd_process *p,
+				struct kfd_event *ev)
+{
+	if (p->signal_event_count == KFD_SIGNAL_EVENT_LIMIT) {
+		pr_warn("amdkfd: Signal event wasn't created because limit was reached\n");
+		return -ENOMEM;
+	}
+
+	if (!allocate_event_notification_slot(devkfd, p, &ev->signal_page,
+						&ev->signal_slot_index)) {
+		pr_warn("amdkfd: Signal event wasn't created because out of kernel memory\n");
+		return -ENOMEM;
+	}
+
+	p->signal_event_count++;
+
+	ev->user_signal_address =
+			&ev->signal_page->user_address[ev->signal_slot_index];
+
+	ev->event_id = make_signal_event_id(ev->signal_page,
+						ev->signal_slot_index);
+
+	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;
+}
+
+/*
+ * No non-signal events are supported yet.
+ * We create them as events that never signal.
+ * Set event calls from user-mode are failed.
+ */
+static int create_other_event(struct kfd_process *p, struct kfd_event *ev)
+{
+	ev->event_id = make_nonsignal_event_id(p);
+	if (ev->event_id == 0)
+		return -ENOMEM;
+
+	return 0;
+}
+
+void kfd_event_init_process(struct kfd_process *p)
+{
+	mutex_init(&p->event_mutex);
+	hash_init(p->events);
+	INIT_LIST_HEAD(&p->signal_event_pages);
+	p->next_nonsignal_event_id = KFD_FIRST_NONSIGNAL_EVENT_ID;
+	p->signal_event_count = 0;
+}
+
+static void destroy_event(struct kfd_process *p, struct kfd_event *ev)
+{
+	if (ev->signal_page != NULL) {
+		release_event_notification_slot(ev->signal_page,
+						ev->signal_slot_index);
+		p->signal_event_count--;
+	}
+
+	/*
+	 * Abandon the list of waiters. Individual waiting threads will
+	 * clean up their own data.
+	 */
+	list_del(&ev->waiters);
+
+	hash_del(&ev->events);
+	kfree(ev);
+}
+
+static void destroy_events(struct kfd_process *p)
+{
+	struct kfd_event *ev;
+	struct hlist_node *tmp;
+	unsigned int hash_bkt;
+
+	hash_for_each_safe(p->events, hash_bkt, tmp, ev, events)
+		destroy_event(p, ev);
+}
+
+/*
+ * 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_pages(struct kfd_process *p)
+{
+	struct signal_page *page, *tmp;
+
+	list_for_each_entry_safe(page, tmp, &p->signal_event_pages,
+					event_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_pages(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_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_LIST_HEAD(&ev->waiters);
+
+	*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 = (ev->signal_page->page_index |
+					KFD_MMAP_EVENTS_MASK);
+			*event_page_offset <<= PAGE_SHIFT;
+			*event_slot_index = ev->signal_slot_index;
+		}
+		break;
+	default:
+		ret = create_other_event(p, ev);
+		break;
+	}
+
+	if (!ret) {
+		hash_add(p->events, &ev->events, ev->event_id);
+
+		*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;
+	struct kfd_event_waiter *next;
+
+	/* Auto reset if the list is non-empty and we're waking someone. */
+	ev->signaled = !ev->auto_reset || list_empty(&ev->waiters);
+
+	list_for_each_entry_safe(waiter, next, &ev->waiters, waiters) {
+		waiter->activated = true;
+
+		/* _init because free_waiters will call list_del */
+		list_del_init(&waiter->waiters);
+
+		wake_up_process(waiter->sleeping_task);
+	}
+}
+
+/* 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(ev->signal_page)[ev->signal_slot_index] =
+						UNSIGNALED_EVENT_SLOT;
+}
+
+static bool is_slot_signaled(struct signal_page *page, unsigned int index)
+{
+	return page_slots(page)[index] != 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;
+
+	/*
+	 * 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 returns a locked process.
+	 */
+	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 >= INTERRUPT_DATA_BITS) {
+		/* Partial ID is a full ID. */
+		ev = lookup_event_by_id(p, partial_id);
+		set_event_from_interrupt(p, ev);
+	} else {
+		/*
+		 * Partial ID is in fact partial. For now we completely
+		 * ignore it, but we could use any bits we did receive to
+		 * search faster.
+		 */
+		struct signal_page *page;
+		unsigned i;
+
+		list_for_each_entry(page, &p->signal_event_pages, event_pages)
+			for (i = 0; i < SLOTS_PER_PAGE; i++)
+				if (is_slot_signaled(page, i)) {
+					ev = lookup_event_by_page_slot(p,
+								page, i);
+					set_event_from_interrupt(p, ev);
+				}
+	}
+
+	mutex_unlock(&p->event_mutex);
+	mutex_unlock(&p->mutex);
+}
+
+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);
+
+	for (i = 0; (event_waiters) && (i < num_events) ; i++) {
+		INIT_LIST_HEAD(&event_waiters[i].waiters);
+		event_waiters[i].sleeping_task = current;
+		event_waiters[i].activated = false;
+	}
+
+	return event_waiters;
+}
+
+static int init_event_waiter(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->activated = ev->signaled;
+	ev->signaled = ev->signaled && !ev->auto_reset;
+
+	list_add(&waiter->waiters, &ev->waiters);
+
+	return 0;
+}
+
+static bool 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].activated) {
+			if (!all)
+				return true;
+
+			activated_count++;
+		}
+	}
+
+	return activated_count == num_events;
+}
+
+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++)
+		list_del(&waiters[i].waiters);
+
+	kfree(waiters);
+}
+
+int kfd_wait_on_events(struct kfd_process *p,
+		       uint32_t num_events, const uint32_t __user *event_ids,
+		       bool all, uint32_t user_timeout_ms,
+		       enum kfd_event_wait_result *wait_result)
+{
+	uint32_t i;
+	int ret = 0;
+	struct kfd_event_waiter *event_waiters = NULL;
+	long timeout = user_timeout_to_jiffies(user_timeout_ms);
+
+	mutex_lock(&p->event_mutex);
+
+	event_waiters = alloc_event_waiters(num_events);
+	if (!event_waiters) {
+		ret = -ENOMEM;
+		goto fail;
+	}
+
+	for (i = 0; i < num_events; i++) {
+		uint32_t event_id;
+
+		ret = get_user(event_id, &event_ids[i]);
+		if (ret)
+			goto fail;
+
+		ret = init_event_waiter(p, &event_waiters[i], event_id);
+		if (ret)
+			goto fail;
+	}
+
+	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;
+		}
+
+		if (test_event_condition(all, num_events, event_waiters)) {
+			*wait_result = KFD_WAIT_COMPLETE;
+			break;
+		}
+
+		if (timeout <= 0) {
+			*wait_result = KFD_WAIT_TIMEOUT;
+			break;
+		}
+
+		timeout = schedule_timeout_interruptible(timeout);
+	}
+	__set_current_state(TASK_RUNNING);
+
+	mutex_lock(&p->event_mutex);
+	free_waiters(num_events, event_waiters);
+	mutex_unlock(&p->event_mutex);
+
+	return ret;
+
+fail:
+	if (event_waiters)
+		free_waiters(num_events, event_waiters);
+
+	mutex_unlock(&p->event_mutex);
+
+	*wait_result = KFD_WAIT_ERROR;
+
+	return ret;
+}
+
+int kfd_event_mmap(struct kfd_process *p, struct vm_area_struct *vma)
+{
+
+	unsigned int page_index;
+	unsigned long pfn;
+	struct signal_page *page;
+
+	/* check required size is logical */
+	if (get_order(KFD_SIGNAL_EVENT_LIMIT * 8) !=
+			get_order(vma->vm_end - vma->vm_start)) {
+		pr_err("amdkfd: event page mmap requested illegal size\n");
+		return -EINVAL;
+	}
+
+	page_index = vma->vm_pgoff;
+
+	page = lookup_signal_page_by_index(p, page_index);
+	if (!page) {
+		/* Probably KFD bug, but mmap is user-accessible. */
+		pr_debug("signal page could not be found for page_index %u\n",
+				page_index);
+		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 */
+	return remap_pfn_range(vma, vma->vm_start, pfn,
+			vma->vm_end - vma->vm_start, vma->vm_page_prot);
+}

drivers/gpu/drm/amd/amdkfd/kfd_events.h

···
+/*
+ * 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.
+ */
+
+#ifndef KFD_EVENTS_H_INCLUDED
+#define KFD_EVENTS_H_INCLUDED
+
+#include <linux/kernel.h>
+#include <linux/hashtable.h>
+#include <linux/types.h>
+#include <linux/list.h>
+#include "kfd_priv.h"
+
+#define KFD_EVENT_ID_NONSIGNAL_MASK 0x80000000U
+#define KFD_FIRST_NONSIGNAL_EVENT_ID KFD_EVENT_ID_NONSIGNAL_MASK
+#define KFD_LAST_NONSIGNAL_EVENT_ID UINT_MAX
+
+/*
+ * Written into kfd_signal_slot_t to indicate that the event is not signaled.
+ * Since the event protocol may need to write the event ID into memory, this
+ * must not be a valid event ID.
+ * For the sake of easy memset-ing, this must be a byte pattern.
+ */
+#define UNSIGNALED_EVENT_SLOT ((uint64_t)-1)
+
+struct kfd_event_waiter;
+struct signal_page;
+
+struct kfd_event {
+	/* All events in process, rooted at kfd_process.events. */
+	struct hlist_node events;
+
+	u32 event_id;
+
+	bool signaled;
+	bool auto_reset;
+
+	int type;
+
+	struct list_head waiters; /* List of kfd_event_waiter by waiters. */
+
+	/* Only for signal events. */
+	struct signal_page *signal_page;
+	unsigned int signal_slot_index;
+	uint64_t __user *user_signal_address;
+};
+
+#define KFD_EVENT_TIMEOUT_IMMEDIATE 0
+#define KFD_EVENT_TIMEOUT_INFINITE 0xFFFFFFFFu
+
+/* Matching HSA_EVENTTYPE */
+#define KFD_EVENT_TYPE_SIGNAL 0
+#define KFD_EVENT_TYPE_DEBUG 5
+
+extern void kfd_signal_event_interrupt(unsigned int pasid, uint32_t partial_id,
+					uint32_t valid_id_bits);
+
+#endif

drivers/gpu/drm/amd/amdkfd/kfd_interrupt.c

···
 				sizeof(uint32_t))];
 
 	while (dequeue_ih_ring_entry(dev, ih_ring_entry))
-		;
+		dev->device_info->event_interrupt_class->interrupt_wq(dev,
+								ih_ring_entry);
 }
 
 bool interrupt_is_wanted(struct kfd_dev *dev, const uint32_t *ih_ring_entry)
 {
-	return false;
+	/* integer and bitwise OR so there is no boolean short-circuiting */
+	unsigned wanted = 0;
+
+	wanted |= dev->device_info->event_interrupt_class->interrupt_isr(dev,
+								ih_ring_entry);
+
+	return wanted != 0;
 }

drivers/gpu/drm/amd/amdkfd/kfd_priv.h

···
 
 #define KFD_SYSFS_FILE_MODE 0444
 
+#define KFD_MMAP_DOORBELL_MASK 0x8000000000000
+#define KFD_MMAP_EVENTS_MASK 0x4000000000000
+
 /*
  * When working with cp scheduler we should assign the HIQ manually or via
  * the radeon driver to a fixed hqd slot, here are the fixed HIQ hqd slot
···
 	CHIP_CARRIZO
 };
 
+struct kfd_event_interrupt_class {
+	bool (*interrupt_isr)(struct kfd_dev *dev,
+				const uint32_t *ih_ring_entry);
+	void (*interrupt_wq)(struct kfd_dev *dev,
+				const uint32_t *ih_ring_entry);
+};
+
 struct kfd_device_info {
 	unsigned int asic_family;
+	const struct kfd_event_interrupt_class *event_interrupt_class;
 	unsigned int max_pasid_bits;
 	size_t ih_ring_entry_size;
 	uint8_t num_of_watch_points;
···
 
 	/*Is the user space process 32 bit?*/
 	bool is_32bit_user_mode;
+
+	/* Event-related data */
+	struct mutex event_mutex;
+	/* All events in process hashed by ID, linked on kfd_event.events. */
+	DECLARE_HASHTABLE(events, 4);
+	struct list_head signal_event_pages;	/* struct slot_page_header.
+								event_pages */
+	u32 next_nonsignal_event_id;
+	size_t signal_event_count;
 };
 
 /**
···
 void kfd_process_destroy_wq(void);
 struct kfd_process *kfd_create_process(const struct task_struct *);
 struct kfd_process *kfd_get_process(const struct task_struct *);
+struct kfd_process *kfd_lookup_process_by_pasid(unsigned int pasid);
 
 struct kfd_process_device *kfd_bind_process_to_device(struct kfd_dev *dev,
 							struct kfd_process *p);
···
 uint64_t kfd_get_number_elems(struct kfd_dev *kfd);
 phys_addr_t kfd_get_process_doorbells(struct kfd_dev *dev,
 					struct kfd_process *process);
+
+/* Events */
+extern const struct kfd_event_interrupt_class event_interrupt_class_cik;
+
+enum kfd_event_wait_result {
+	KFD_WAIT_COMPLETE,
+	KFD_WAIT_TIMEOUT,
+	KFD_WAIT_ERROR
+};
+
+void kfd_event_init_process(struct kfd_process *p);
+void kfd_event_free_process(struct kfd_process *p);
+int kfd_event_mmap(struct kfd_process *process, struct vm_area_struct *vma);
+int kfd_wait_on_events(struct kfd_process *p,
+		       uint32_t num_events, const uint32_t __user *event_ids,
+		       bool all, uint32_t user_timeout_ms,
+		       enum kfd_event_wait_result *wait_result);
+void kfd_signal_event_interrupt(unsigned int pasid, uint32_t partial_id,
+				uint32_t valid_id_bits);
+int kfd_set_event(struct kfd_process *p, uint32_t event_id);
+int kfd_reset_event(struct kfd_process *p, uint32_t event_id);
+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 kfd_event_destroy(struct kfd_process *p, uint32_t event_id);
 
 #endif

drivers/gpu/drm/amd/amdkfd/kfd_process.c

···
 		kfree(pdd);
 	}
 
+	kfd_event_free_process(p);
+
 	kfd_pasid_free(p->pasid);
 
 	mutex_unlock(&p->mutex);
···
 	process->queue_array_size = INITIAL_QUEUE_ARRAY_SIZE;
 
 	INIT_LIST_HEAD(&process->per_device_data);
+
+	kfd_event_init_process(process);
 
 	err = pqm_init(&process->pqm, process);
 	if (err != 0)
···
 bool kfd_has_process_device_data(struct kfd_process *p)
 {
 	return !(list_empty(&p->per_device_data));
+}
+
+/* This returns with process->mutex locked. */
+struct kfd_process *kfd_lookup_process_by_pasid(unsigned int pasid)
+{
+	struct kfd_process *p;
+	unsigned int temp;
+
+	int idx = srcu_read_lock(&kfd_processes_srcu);
+
+	hash_for_each_rcu(kfd_processes_table, temp, p, kfd_processes) {
+		if (p->pasid == pasid) {
+			mutex_lock(&p->mutex);
+			break;
+		}
+	}
+
+	srcu_read_unlock(&kfd_processes_srcu, idx);
+
+	return p;
 }