1/*
  2 * Copyright 2020 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/poll.h>
 24#include <linux/wait.h>
 25#include <linux/anon_inodes.h>
 26#include <uapi/linux/kfd_ioctl.h>
 27#include "amdgpu_vm.h"
 28#include "kfd_priv.h"
 29#include "kfd_smi_events.h"
 30
 31struct kfd_smi_client {
 32	struct list_head list;
 33	struct kfifo fifo;
 34	wait_queue_head_t wait_queue;
 35	/* events enabled */
 36	uint64_t events;
 37	struct kfd_dev *dev;
 38	spinlock_t lock;
 39};
 40
 41#define MAX_KFIFO_SIZE	1024
 42
 43static __poll_t kfd_smi_ev_poll(struct file *, struct poll_table_struct *);
 44static ssize_t kfd_smi_ev_read(struct file *, char __user *, size_t, loff_t *);
 45static ssize_t kfd_smi_ev_write(struct file *, const char __user *, size_t,
 46				loff_t *);
 47static int kfd_smi_ev_release(struct inode *, struct file *);
 48
 49static const char kfd_smi_name[] = "kfd_smi_ev";
 50
 51static const struct file_operations kfd_smi_ev_fops = {
 52	.owner = THIS_MODULE,
 53	.poll = kfd_smi_ev_poll,
 54	.read = kfd_smi_ev_read,
 55	.write = kfd_smi_ev_write,
 56	.release = kfd_smi_ev_release
 57};
 58
 59static __poll_t kfd_smi_ev_poll(struct file *filep,
 60				struct poll_table_struct *wait)
 61{
 62	struct kfd_smi_client *client = filep->private_data;
 63	__poll_t mask = 0;
 64
 65	poll_wait(filep, &client->wait_queue, wait);
 66
 67	spin_lock(&client->lock);
 68	if (!kfifo_is_empty(&client->fifo))
 69		mask = EPOLLIN | EPOLLRDNORM;
 70	spin_unlock(&client->lock);
 71
 72	return mask;
 73}
 74
 75static ssize_t kfd_smi_ev_read(struct file *filep, char __user *user,
 76			       size_t size, loff_t *offset)
 77{
 78	int ret;
 79	size_t to_copy;
 80	struct kfd_smi_client *client = filep->private_data;
 81	unsigned char *buf;
 82
 83	buf = kmalloc(MAX_KFIFO_SIZE * sizeof(*buf), GFP_KERNEL);
 84	if (!buf)
 85		return -ENOMEM;
 86
 87	/* kfifo_to_user can sleep so we can't use spinlock protection around
 88	 * it. Instead, we kfifo out as spinlocked then copy them to the user.
 89	 */
 90	spin_lock(&client->lock);
 91	to_copy = kfifo_len(&client->fifo);
 92	if (!to_copy) {
 93		spin_unlock(&client->lock);
 94		ret = -EAGAIN;
 95		goto ret_err;
 96	}
 97	to_copy = min3(size, sizeof(buf), to_copy);
 98	ret = kfifo_out(&client->fifo, buf, to_copy);
 99	spin_unlock(&client->lock);
100	if (ret <= 0) {
101		ret = -EAGAIN;
102		goto ret_err;
103	}
104
105	ret = copy_to_user(user, buf, to_copy);
106	if (ret) {
107		ret = -EFAULT;
108		goto ret_err;
109	}
110
111	kfree(buf);
112	return to_copy;
113
114ret_err:
115	kfree(buf);
116	return ret;
117}
118
119static ssize_t kfd_smi_ev_write(struct file *filep, const char __user *user,
120				size_t size, loff_t *offset)
121{
122	struct kfd_smi_client *client = filep->private_data;
123	uint64_t events;
124
125	if (!access_ok(user, size) || size < sizeof(events))
126		return -EFAULT;
127	if (copy_from_user(&events, user, sizeof(events)))
128		return -EFAULT;
129
130	WRITE_ONCE(client->events, events);
131
132	return sizeof(events);
133}
134
135static int kfd_smi_ev_release(struct inode *inode, struct file *filep)
136{
137	struct kfd_smi_client *client = filep->private_data;
138	struct kfd_dev *dev = client->dev;
139
140	spin_lock(&dev->smi_lock);
141	list_del_rcu(&client->list);
142	spin_unlock(&dev->smi_lock);
143
144	synchronize_rcu();
145	kfifo_free(&client->fifo);
146	kfree(client);
147
148	return 0;
149}
150
151void kfd_smi_event_update_vmfault(struct kfd_dev *dev, uint16_t pasid)
152{
153	struct amdgpu_device *adev = (struct amdgpu_device *)dev->kgd;
154	struct amdgpu_task_info task_info;
155	/* VmFault msg = (hex)uint32_pid(8) + :(1) + task name(16) = 25 */
156	/* 16 bytes event + 1 byte space + 25 bytes msg + 1 byte \n = 43
157	 */
158	char fifo_in[43];
159	struct kfd_smi_client *client;
160	int len;
161
162	if (list_empty(&dev->smi_clients))
163		return;
164
165	memset(&task_info, 0, sizeof(struct amdgpu_task_info));
166	amdgpu_vm_get_task_info(adev, pasid, &task_info);
167	/* Report VM faults from user applications, not retry from kernel */
168	if (!task_info.pid)
169		return;
170
171	len = snprintf(fifo_in, 43, "%x %x:%s\n", KFD_SMI_EVENT_VMFAULT,
172		task_info.pid, task_info.task_name);
173
174	rcu_read_lock();
175
176	list_for_each_entry_rcu(client, &dev->smi_clients, list) {
177		if (!(READ_ONCE(client->events) & KFD_SMI_EVENT_VMFAULT))
178			continue;
179		spin_lock(&client->lock);
180		if (kfifo_avail(&client->fifo) >= len) {
181			kfifo_in(&client->fifo, fifo_in, len);
182			wake_up_all(&client->wait_queue);
183		}
184		else
185			pr_debug("smi_event(vmfault): no space left\n");
186		spin_unlock(&client->lock);
187	}
188
189	rcu_read_unlock();
190}
191
192int kfd_smi_event_open(struct kfd_dev *dev, uint32_t *fd)
193{
194	struct kfd_smi_client *client;
195	int ret;
196
197	client = kzalloc(sizeof(struct kfd_smi_client), GFP_KERNEL);
198	if (!client)
199		return -ENOMEM;
200	INIT_LIST_HEAD(&client->list);
201
202	ret = kfifo_alloc(&client->fifo, MAX_KFIFO_SIZE, GFP_KERNEL);
203	if (ret) {
204		kfree(client);
205		return ret;
206	}
207
208	ret = anon_inode_getfd(kfd_smi_name, &kfd_smi_ev_fops, (void *)client,
209			       O_RDWR);
210	if (ret < 0) {
211		kfifo_free(&client->fifo);
212		kfree(client);
213		return ret;
214	}
215	*fd = ret;
216
217	init_waitqueue_head(&client->wait_queue);
218	spin_lock_init(&client->lock);
219	client->events = 0;
220	client->dev = dev;
221
222	spin_lock(&dev->smi_lock);
223	list_add_rcu(&client->list, &dev->smi_clients);
224	spin_unlock(&dev->smi_lock);
225
226	return 0;
227}