1// SPDX-License-Identifier: GPL-2.0+
  2// Copyright 2017 IBM Corp.
  3#include <linux/fs.h>
  4#include <linux/poll.h>
  5#include <linux/sched/signal.h>
  6#include <linux/uaccess.h>
  7#include <uapi/misc/ocxl.h>
  8#include "ocxl_internal.h"
  9
 10
 11#define OCXL_NUM_MINORS 256 /* Total to reserve */
 12
 13static dev_t ocxl_dev;
 14static struct class *ocxl_class;
 15static struct mutex minors_idr_lock;
 16static struct idr minors_idr;
 17
 18static struct ocxl_afu *find_and_get_afu(dev_t devno)
 19{
 20	struct ocxl_afu *afu;
 21	int afu_minor;
 22
 23	afu_minor = MINOR(devno);
 24	/*
 25	 * We don't declare an RCU critical section here, as our AFU
 26	 * is protected by a reference counter on the device. By the time the
 27	 * minor number of a device is removed from the idr, the ref count of
 28	 * the device is already at 0, so no user API will access that AFU and
 29	 * this function can't return it.
 30	 */
 31	afu = idr_find(&minors_idr, afu_minor);
 32	if (afu)
 33		ocxl_afu_get(afu);
 34	return afu;
 35}
 36
 37static int allocate_afu_minor(struct ocxl_afu *afu)
 38{
 39	int minor;
 40
 41	mutex_lock(&minors_idr_lock);
 42	minor = idr_alloc(&minors_idr, afu, 0, OCXL_NUM_MINORS, GFP_KERNEL);
 43	mutex_unlock(&minors_idr_lock);
 44	return minor;
 45}
 46
 47static void free_afu_minor(struct ocxl_afu *afu)
 48{
 49	mutex_lock(&minors_idr_lock);
 50	idr_remove(&minors_idr, MINOR(afu->dev.devt));
 51	mutex_unlock(&minors_idr_lock);
 52}
 53
 54static int afu_open(struct inode *inode, struct file *file)
 55{
 56	struct ocxl_afu *afu;
 57	struct ocxl_context *ctx;
 58	int rc;
 59
 60	pr_debug("%s for device %x\n", __func__, inode->i_rdev);
 61
 62	afu = find_and_get_afu(inode->i_rdev);
 63	if (!afu)
 64		return -ENODEV;
 65
 66	ctx = ocxl_context_alloc();
 67	if (!ctx) {
 68		rc = -ENOMEM;
 69		goto put_afu;
 70	}
 71
 72	rc = ocxl_context_init(ctx, afu, inode->i_mapping);
 73	if (rc)
 74		goto put_afu;
 75	file->private_data = ctx;
 76	ocxl_afu_put(afu);
 77	return 0;
 78
 79put_afu:
 80	ocxl_afu_put(afu);
 81	return rc;
 82}
 83
 84static long afu_ioctl_attach(struct ocxl_context *ctx,
 85			struct ocxl_ioctl_attach __user *uarg)
 86{
 87	struct ocxl_ioctl_attach arg;
 88	u64 amr = 0;
 89	int rc;
 90
 91	pr_debug("%s for context %d\n", __func__, ctx->pasid);
 92
 93	if (copy_from_user(&arg, uarg, sizeof(arg)))
 94		return -EFAULT;
 95
 96	/* Make sure reserved fields are not set for forward compatibility */
 97	if (arg.reserved1 || arg.reserved2 || arg.reserved3)
 98		return -EINVAL;
 99
100	amr = arg.amr & mfspr(SPRN_UAMOR);
101	rc = ocxl_context_attach(ctx, amr);
102	return rc;
103}
104
105static long afu_ioctl_get_metadata(struct ocxl_context *ctx,
106		struct ocxl_ioctl_metadata __user *uarg)
107{
108	struct ocxl_ioctl_metadata arg;
109
110	memset(&arg, 0, sizeof(arg));
111
112	arg.version = 0;
113
114	arg.afu_version_major = ctx->afu->config.version_major;
115	arg.afu_version_minor = ctx->afu->config.version_minor;
116	arg.pasid = ctx->pasid;
117	arg.pp_mmio_size = ctx->afu->config.pp_mmio_stride;
118	arg.global_mmio_size = ctx->afu->config.global_mmio_size;
119
120	if (copy_to_user(uarg, &arg, sizeof(arg)))
121		return -EFAULT;
122
123	return 0;
124}
125
126#define CMD_STR(x) (x == OCXL_IOCTL_ATTACH ? "ATTACH" :			\
127			x == OCXL_IOCTL_IRQ_ALLOC ? "IRQ_ALLOC" :	\
128			x == OCXL_IOCTL_IRQ_FREE ? "IRQ_FREE" :		\
129			x == OCXL_IOCTL_IRQ_SET_FD ? "IRQ_SET_FD" :	\
130			x == OCXL_IOCTL_GET_METADATA ? "GET_METADATA" :	\
131			"UNKNOWN")
132
133static long afu_ioctl(struct file *file, unsigned int cmd,
134		unsigned long args)
135{
136	struct ocxl_context *ctx = file->private_data;
137	struct ocxl_ioctl_irq_fd irq_fd;
138	u64 irq_offset;
139	long rc;
140
141	pr_debug("%s for context %d, command %s\n", __func__, ctx->pasid,
142		CMD_STR(cmd));
143
144	if (ctx->status == CLOSED)
145		return -EIO;
146
147	switch (cmd) {
148	case OCXL_IOCTL_ATTACH:
149		rc = afu_ioctl_attach(ctx,
150				(struct ocxl_ioctl_attach __user *) args);
151		break;
152
153	case OCXL_IOCTL_IRQ_ALLOC:
154		rc = ocxl_afu_irq_alloc(ctx, &irq_offset);
155		if (!rc) {
156			rc = copy_to_user((u64 __user *) args, &irq_offset,
157					sizeof(irq_offset));
158			if (rc) {
159				ocxl_afu_irq_free(ctx, irq_offset);
160				return -EFAULT;
161			}
162		}
163		break;
164
165	case OCXL_IOCTL_IRQ_FREE:
166		rc = copy_from_user(&irq_offset, (u64 __user *) args,
167				sizeof(irq_offset));
168		if (rc)
169			return -EFAULT;
170		rc = ocxl_afu_irq_free(ctx, irq_offset);
171		break;
172
173	case OCXL_IOCTL_IRQ_SET_FD:
174		rc = copy_from_user(&irq_fd, (u64 __user *) args,
175				sizeof(irq_fd));
176		if (rc)
177			return -EFAULT;
178		if (irq_fd.reserved)
179			return -EINVAL;
180		rc = ocxl_afu_irq_set_fd(ctx, irq_fd.irq_offset,
181					irq_fd.eventfd);
182		break;
183
184	case OCXL_IOCTL_GET_METADATA:
185		rc = afu_ioctl_get_metadata(ctx,
186				(struct ocxl_ioctl_metadata __user *) args);
187		break;
188
189	default:
190		rc = -EINVAL;
191	}
192	return rc;
193}
194
195static long afu_compat_ioctl(struct file *file, unsigned int cmd,
196			unsigned long args)
197{
198	return afu_ioctl(file, cmd, args);
199}
200
201static int afu_mmap(struct file *file, struct vm_area_struct *vma)
202{
203	struct ocxl_context *ctx = file->private_data;
204
205	pr_debug("%s for context %d\n", __func__, ctx->pasid);
206	return ocxl_context_mmap(ctx, vma);
207}
208
209static bool has_xsl_error(struct ocxl_context *ctx)
210{
211	bool ret;
212
213	mutex_lock(&ctx->xsl_error_lock);
214	ret = !!ctx->xsl_error.addr;
215	mutex_unlock(&ctx->xsl_error_lock);
216
217	return ret;
218}
219
220/*
221 * Are there any events pending on the AFU
222 * ctx: The AFU context
223 * Returns: true if there are events pending
224 */
225static bool afu_events_pending(struct ocxl_context *ctx)
226{
227	if (has_xsl_error(ctx))
228		return true;
229	return false;
230}
231
232static unsigned int afu_poll(struct file *file, struct poll_table_struct *wait)
233{
234	struct ocxl_context *ctx = file->private_data;
235	unsigned int mask = 0;
236	bool closed;
237
238	pr_debug("%s for context %d\n", __func__, ctx->pasid);
239
240	poll_wait(file, &ctx->events_wq, wait);
241
242	mutex_lock(&ctx->status_mutex);
243	closed = (ctx->status == CLOSED);
244	mutex_unlock(&ctx->status_mutex);
245
246	if (afu_events_pending(ctx))
247		mask = EPOLLIN | EPOLLRDNORM;
248	else if (closed)
249		mask = EPOLLERR;
250
251	return mask;
252}
253
254/*
255 * Populate the supplied buffer with a single XSL error
256 * ctx:	The AFU context to report the error from
257 * header: the event header to populate
258 * buf: The buffer to write the body into (should be at least
259 *      AFU_EVENT_BODY_XSL_ERROR_SIZE)
260 * Return: the amount of buffer that was populated
261 */
262static ssize_t append_xsl_error(struct ocxl_context *ctx,
263				struct ocxl_kernel_event_header *header,
264				char __user *buf)
265{
266	struct ocxl_kernel_event_xsl_fault_error body;
267
268	memset(&body, 0, sizeof(body));
269
270	mutex_lock(&ctx->xsl_error_lock);
271	if (!ctx->xsl_error.addr) {
272		mutex_unlock(&ctx->xsl_error_lock);
273		return 0;
274	}
275
276	body.addr = ctx->xsl_error.addr;
277	body.dsisr = ctx->xsl_error.dsisr;
278	body.count = ctx->xsl_error.count;
279
280	ctx->xsl_error.addr = 0;
281	ctx->xsl_error.dsisr = 0;
282	ctx->xsl_error.count = 0;
283
284	mutex_unlock(&ctx->xsl_error_lock);
285
286	header->type = OCXL_AFU_EVENT_XSL_FAULT_ERROR;
287
288	if (copy_to_user(buf, &body, sizeof(body)))
289		return -EFAULT;
290
291	return sizeof(body);
292}
293
294#define AFU_EVENT_BODY_MAX_SIZE sizeof(struct ocxl_kernel_event_xsl_fault_error)
295
296/*
297 * Reports events on the AFU
298 * Format:
299 *	Header (struct ocxl_kernel_event_header)
300 *	Body (struct ocxl_kernel_event_*)
301 *	Header...
302 */
303static ssize_t afu_read(struct file *file, char __user *buf, size_t count,
304			loff_t *off)
305{
306	struct ocxl_context *ctx = file->private_data;
307	struct ocxl_kernel_event_header header;
308	ssize_t rc;
309	ssize_t used = 0;
310	DEFINE_WAIT(event_wait);
311
312	memset(&header, 0, sizeof(header));
313
314	/* Require offset to be 0 */
315	if (*off != 0)
316		return -EINVAL;
317
318	if (count < (sizeof(struct ocxl_kernel_event_header) +
319			AFU_EVENT_BODY_MAX_SIZE))
320		return -EINVAL;
321
322	for (;;) {
323		prepare_to_wait(&ctx->events_wq, &event_wait,
324				TASK_INTERRUPTIBLE);
325
326		if (afu_events_pending(ctx))
327			break;
328
329		if (ctx->status == CLOSED)
330			break;
331
332		if (file->f_flags & O_NONBLOCK) {
333			finish_wait(&ctx->events_wq, &event_wait);
334			return -EAGAIN;
335		}
336
337		if (signal_pending(current)) {
338			finish_wait(&ctx->events_wq, &event_wait);
339			return -ERESTARTSYS;
340		}
341
342		schedule();
343	}
344
345	finish_wait(&ctx->events_wq, &event_wait);
346
347	if (has_xsl_error(ctx)) {
348		used = append_xsl_error(ctx, &header, buf + sizeof(header));
349		if (used < 0)
350			return used;
351	}
352
353	if (!afu_events_pending(ctx))
354		header.flags |= OCXL_KERNEL_EVENT_FLAG_LAST;
355
356	if (copy_to_user(buf, &header, sizeof(header)))
357		return -EFAULT;
358
359	used += sizeof(header);
360
361	rc = used;
362	return rc;
363}
364
365static int afu_release(struct inode *inode, struct file *file)
366{
367	struct ocxl_context *ctx = file->private_data;
368	int rc;
369
370	pr_debug("%s for device %x\n", __func__, inode->i_rdev);
371	rc = ocxl_context_detach(ctx);
372	mutex_lock(&ctx->mapping_lock);
373	ctx->mapping = NULL;
374	mutex_unlock(&ctx->mapping_lock);
375	wake_up_all(&ctx->events_wq);
376	if (rc != -EBUSY)
377		ocxl_context_free(ctx);
378	return 0;
379}
380
381static const struct file_operations ocxl_afu_fops = {
382	.owner		= THIS_MODULE,
383	.open           = afu_open,
384	.unlocked_ioctl = afu_ioctl,
385	.compat_ioctl   = afu_compat_ioctl,
386	.mmap           = afu_mmap,
387	.poll           = afu_poll,
388	.read           = afu_read,
389	.release        = afu_release,
390};
391
392int ocxl_create_cdev(struct ocxl_afu *afu)
393{
394	int rc;
395
396	cdev_init(&afu->cdev, &ocxl_afu_fops);
397	rc = cdev_add(&afu->cdev, afu->dev.devt, 1);
398	if (rc) {
399		dev_err(&afu->dev, "Unable to add afu char device: %d\n", rc);
400		return rc;
401	}
402	return 0;
403}
404
405void ocxl_destroy_cdev(struct ocxl_afu *afu)
406{
407	cdev_del(&afu->cdev);
408}
409
410int ocxl_register_afu(struct ocxl_afu *afu)
411{
412	int minor;
413
414	minor = allocate_afu_minor(afu);
415	if (minor < 0)
416		return minor;
417	afu->dev.devt = MKDEV(MAJOR(ocxl_dev), minor);
418	afu->dev.class = ocxl_class;
419	return device_register(&afu->dev);
420}
421
422void ocxl_unregister_afu(struct ocxl_afu *afu)
423{
424	free_afu_minor(afu);
425}
426
427static char *ocxl_devnode(struct device *dev, umode_t *mode)
428{
429	return kasprintf(GFP_KERNEL, "ocxl/%s", dev_name(dev));
430}
431
432int ocxl_file_init(void)
433{
434	int rc;
435
436	mutex_init(&minors_idr_lock);
437	idr_init(&minors_idr);
438
439	rc = alloc_chrdev_region(&ocxl_dev, 0, OCXL_NUM_MINORS, "ocxl");
440	if (rc) {
441		pr_err("Unable to allocate ocxl major number: %d\n", rc);
442		return rc;
443	}
444
445	ocxl_class = class_create(THIS_MODULE, "ocxl");
446	if (IS_ERR(ocxl_class)) {
447		pr_err("Unable to create ocxl class\n");
448		unregister_chrdev_region(ocxl_dev, OCXL_NUM_MINORS);
449		return PTR_ERR(ocxl_class);
450	}
451
452	ocxl_class->devnode = ocxl_devnode;
453	return 0;
454}
455
456void ocxl_file_exit(void)
457{
458	class_destroy(ocxl_class);
459	unregister_chrdev_region(ocxl_dev, OCXL_NUM_MINORS);
460	idr_destroy(&minors_idr);
461}