xref: /linux/drivers/misc/ocxl/file.c (revision 856e7c4b619af622d56b3b454f7bec32a170ac99) 
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 <asm/reg.h>
9 #include <asm/switch_to.h>
10 #include "ocxl_internal.h"
11 
12 
13 #define OCXL_NUM_MINORS 256 /* Total to reserve */
14 
15 static dev_t ocxl_dev;
16 static struct class *ocxl_class;
17 static struct mutex minors_idr_lock;
18 static struct idr minors_idr;
19 
20 static struct ocxl_afu *find_and_get_afu(dev_t devno)
21 {
22 	struct ocxl_afu *afu;
23 	int afu_minor;
24 
25 	afu_minor = MINOR(devno);
26 	/*
27 	 * We don't declare an RCU critical section here, as our AFU
28 	 * is protected by a reference counter on the device. By the time the
29 	 * minor number of a device is removed from the idr, the ref count of
30 	 * the device is already at 0, so no user API will access that AFU and
31 	 * this function can't return it.
32 	 */
33 	afu = idr_find(&minors_idr, afu_minor);
34 	if (afu)
35 		ocxl_afu_get(afu);
36 	return afu;
37 }
38 
39 static int allocate_afu_minor(struct ocxl_afu *afu)
40 {
41 	int minor;
42 
43 	mutex_lock(&minors_idr_lock);
44 	minor = idr_alloc(&minors_idr, afu, 0, OCXL_NUM_MINORS, GFP_KERNEL);
45 	mutex_unlock(&minors_idr_lock);
46 	return minor;
47 }
48 
49 static void free_afu_minor(struct ocxl_afu *afu)
50 {
51 	mutex_lock(&minors_idr_lock);
52 	idr_remove(&minors_idr, MINOR(afu->dev.devt));
53 	mutex_unlock(&minors_idr_lock);
54 }
55 
56 static int afu_open(struct inode *inode, struct file *file)
57 {
58 	struct ocxl_afu *afu;
59 	struct ocxl_context *ctx;
60 	int rc;
61 
62 	pr_debug("%s for device %x\n", __func__, inode->i_rdev);
63 
64 	afu = find_and_get_afu(inode->i_rdev);
65 	if (!afu)
66 		return -ENODEV;
67 
68 	ctx = ocxl_context_alloc();
69 	if (!ctx) {
70 		rc = -ENOMEM;
71 		goto put_afu;
72 	}
73 
74 	rc = ocxl_context_init(ctx, afu, inode->i_mapping);
75 	if (rc)
76 		goto put_afu;
77 	file->private_data = ctx;
78 	ocxl_afu_put(afu);
79 	return 0;
80 
81 put_afu:
82 	ocxl_afu_put(afu);
83 	return rc;
84 }
85 
86 static long afu_ioctl_attach(struct ocxl_context *ctx,
87 			struct ocxl_ioctl_attach __user *uarg)
88 {
89 	struct ocxl_ioctl_attach arg;
90 	u64 amr = 0;
91 	int rc;
92 
93 	pr_debug("%s for context %d\n", __func__, ctx->pasid);
94 
95 	if (copy_from_user(&arg, uarg, sizeof(arg)))
96 		return -EFAULT;
97 
98 	/* Make sure reserved fields are not set for forward compatibility */
99 	if (arg.reserved1 || arg.reserved2 || arg.reserved3)
100 		return -EINVAL;
101 
102 	amr = arg.amr & mfspr(SPRN_UAMOR);
103 	rc = ocxl_context_attach(ctx, amr);
104 	return rc;
105 }
106 
107 static long afu_ioctl_get_metadata(struct ocxl_context *ctx,
108 		struct ocxl_ioctl_metadata __user *uarg)
109 {
110 	struct ocxl_ioctl_metadata arg;
111 
112 	memset(&arg, 0, sizeof(arg));
113 
114 	arg.version = 0;
115 
116 	arg.afu_version_major = ctx->afu->config.version_major;
117 	arg.afu_version_minor = ctx->afu->config.version_minor;
118 	arg.pasid = ctx->pasid;
119 	arg.pp_mmio_size = ctx->afu->config.pp_mmio_stride;
120 	arg.global_mmio_size = ctx->afu->config.global_mmio_size;
121 
122 	if (copy_to_user(uarg, &arg, sizeof(arg)))
123 		return -EFAULT;
124 
125 	return 0;
126 }
127 
128 #ifdef CONFIG_PPC64
129 static long afu_ioctl_enable_p9_wait(struct ocxl_context *ctx,
130 		struct ocxl_ioctl_p9_wait __user *uarg)
131 {
132 	struct ocxl_ioctl_p9_wait arg;
133 
134 	memset(&arg, 0, sizeof(arg));
135 
136 	if (cpu_has_feature(CPU_FTR_P9_TIDR)) {
137 		enum ocxl_context_status status;
138 
139 		// Locks both status & tidr
140 		mutex_lock(&ctx->status_mutex);
141 		if (!ctx->tidr) {
142 			if (set_thread_tidr(current)) {
143 				mutex_unlock(&ctx->status_mutex);
144 				return -ENOENT;
145 			}
146 
147 			ctx->tidr = current->thread.tidr;
148 		}
149 
150 		status = ctx->status;
151 		mutex_unlock(&ctx->status_mutex);
152 
153 		if (status == ATTACHED) {
154 			int rc;
155 			struct link *link = ctx->afu->fn->link;
156 
157 			rc = ocxl_link_update_pe(link, ctx->pasid, ctx->tidr);
158 			if (rc)
159 				return rc;
160 		}
161 
162 		arg.thread_id = ctx->tidr;
163 	} else
164 		return -ENOENT;
165 
166 	if (copy_to_user(uarg, &arg, sizeof(arg)))
167 		return -EFAULT;
168 
169 	return 0;
170 }
171 #endif
172 
173 
174 static long afu_ioctl_get_features(struct ocxl_context *ctx,
175 		struct ocxl_ioctl_features __user *uarg)
176 {
177 	struct ocxl_ioctl_features arg;
178 
179 	memset(&arg, 0, sizeof(arg));
180 
181 #ifdef CONFIG_PPC64
182 	if (cpu_has_feature(CPU_FTR_P9_TIDR))
183 		arg.flags[0] |= OCXL_IOCTL_FEATURES_FLAGS0_P9_WAIT;
184 #endif
185 
186 	if (copy_to_user(uarg, &arg, sizeof(arg)))
187 		return -EFAULT;
188 
189 	return 0;
190 }
191 
192 #define CMD_STR(x) (x == OCXL_IOCTL_ATTACH ? "ATTACH" :			\
193 			x == OCXL_IOCTL_IRQ_ALLOC ? "IRQ_ALLOC" :	\
194 			x == OCXL_IOCTL_IRQ_FREE ? "IRQ_FREE" :		\
195 			x == OCXL_IOCTL_IRQ_SET_FD ? "IRQ_SET_FD" :	\
196 			x == OCXL_IOCTL_GET_METADATA ? "GET_METADATA" :	\
197 			x == OCXL_IOCTL_ENABLE_P9_WAIT ? "ENABLE_P9_WAIT" :	\
198 			x == OCXL_IOCTL_GET_FEATURES ? "GET_FEATURES" :	\
199 			"UNKNOWN")
200 
201 static long afu_ioctl(struct file *file, unsigned int cmd,
202 		unsigned long args)
203 {
204 	struct ocxl_context *ctx = file->private_data;
205 	struct ocxl_ioctl_irq_fd irq_fd;
206 	u64 irq_offset;
207 	long rc;
208 
209 	pr_debug("%s for context %d, command %s\n", __func__, ctx->pasid,
210 		CMD_STR(cmd));
211 
212 	if (ctx->status == CLOSED)
213 		return -EIO;
214 
215 	switch (cmd) {
216 	case OCXL_IOCTL_ATTACH:
217 		rc = afu_ioctl_attach(ctx,
218 				(struct ocxl_ioctl_attach __user *) args);
219 		break;
220 
221 	case OCXL_IOCTL_IRQ_ALLOC:
222 		rc = ocxl_afu_irq_alloc(ctx, &irq_offset);
223 		if (!rc) {
224 			rc = copy_to_user((u64 __user *) args, &irq_offset,
225 					sizeof(irq_offset));
226 			if (rc) {
227 				ocxl_afu_irq_free(ctx, irq_offset);
228 				return -EFAULT;
229 			}
230 		}
231 		break;
232 
233 	case OCXL_IOCTL_IRQ_FREE:
234 		rc = copy_from_user(&irq_offset, (u64 __user *) args,
235 				sizeof(irq_offset));
236 		if (rc)
237 			return -EFAULT;
238 		rc = ocxl_afu_irq_free(ctx, irq_offset);
239 		break;
240 
241 	case OCXL_IOCTL_IRQ_SET_FD:
242 		rc = copy_from_user(&irq_fd, (u64 __user *) args,
243 				sizeof(irq_fd));
244 		if (rc)
245 			return -EFAULT;
246 		if (irq_fd.reserved)
247 			return -EINVAL;
248 		rc = ocxl_afu_irq_set_fd(ctx, irq_fd.irq_offset,
249 					irq_fd.eventfd);
250 		break;
251 
252 	case OCXL_IOCTL_GET_METADATA:
253 		rc = afu_ioctl_get_metadata(ctx,
254 				(struct ocxl_ioctl_metadata __user *) args);
255 		break;
256 
257 #ifdef CONFIG_PPC64
258 	case OCXL_IOCTL_ENABLE_P9_WAIT:
259 		rc = afu_ioctl_enable_p9_wait(ctx,
260 				(struct ocxl_ioctl_p9_wait __user *) args);
261 		break;
262 #endif
263 
264 	case OCXL_IOCTL_GET_FEATURES:
265 		rc = afu_ioctl_get_features(ctx,
266 				(struct ocxl_ioctl_features __user *) args);
267 		break;
268 
269 	default:
270 		rc = -EINVAL;
271 	}
272 	return rc;
273 }
274 
275 static long afu_compat_ioctl(struct file *file, unsigned int cmd,
276 			unsigned long args)
277 {
278 	return afu_ioctl(file, cmd, args);
279 }
280 
281 static int afu_mmap(struct file *file, struct vm_area_struct *vma)
282 {
283 	struct ocxl_context *ctx = file->private_data;
284 
285 	pr_debug("%s for context %d\n", __func__, ctx->pasid);
286 	return ocxl_context_mmap(ctx, vma);
287 }
288 
289 static bool has_xsl_error(struct ocxl_context *ctx)
290 {
291 	bool ret;
292 
293 	mutex_lock(&ctx->xsl_error_lock);
294 	ret = !!ctx->xsl_error.addr;
295 	mutex_unlock(&ctx->xsl_error_lock);
296 
297 	return ret;
298 }
299 
300 /*
301  * Are there any events pending on the AFU
302  * ctx: The AFU context
303  * Returns: true if there are events pending
304  */
305 static bool afu_events_pending(struct ocxl_context *ctx)
306 {
307 	if (has_xsl_error(ctx))
308 		return true;
309 	return false;
310 }
311 
312 static unsigned int afu_poll(struct file *file, struct poll_table_struct *wait)
313 {
314 	struct ocxl_context *ctx = file->private_data;
315 	unsigned int mask = 0;
316 	bool closed;
317 
318 	pr_debug("%s for context %d\n", __func__, ctx->pasid);
319 
320 	poll_wait(file, &ctx->events_wq, wait);
321 
322 	mutex_lock(&ctx->status_mutex);
323 	closed = (ctx->status == CLOSED);
324 	mutex_unlock(&ctx->status_mutex);
325 
326 	if (afu_events_pending(ctx))
327 		mask = EPOLLIN | EPOLLRDNORM;
328 	else if (closed)
329 		mask = EPOLLERR;
330 
331 	return mask;
332 }
333 
334 /*
335  * Populate the supplied buffer with a single XSL error
336  * ctx:	The AFU context to report the error from
337  * header: the event header to populate
338  * buf: The buffer to write the body into (should be at least
339  *      AFU_EVENT_BODY_XSL_ERROR_SIZE)
340  * Return: the amount of buffer that was populated
341  */
342 static ssize_t append_xsl_error(struct ocxl_context *ctx,
343 				struct ocxl_kernel_event_header *header,
344 				char __user *buf)
345 {
346 	struct ocxl_kernel_event_xsl_fault_error body;
347 
348 	memset(&body, 0, sizeof(body));
349 
350 	mutex_lock(&ctx->xsl_error_lock);
351 	if (!ctx->xsl_error.addr) {
352 		mutex_unlock(&ctx->xsl_error_lock);
353 		return 0;
354 	}
355 
356 	body.addr = ctx->xsl_error.addr;
357 	body.dsisr = ctx->xsl_error.dsisr;
358 	body.count = ctx->xsl_error.count;
359 
360 	ctx->xsl_error.addr = 0;
361 	ctx->xsl_error.dsisr = 0;
362 	ctx->xsl_error.count = 0;
363 
364 	mutex_unlock(&ctx->xsl_error_lock);
365 
366 	header->type = OCXL_AFU_EVENT_XSL_FAULT_ERROR;
367 
368 	if (copy_to_user(buf, &body, sizeof(body)))
369 		return -EFAULT;
370 
371 	return sizeof(body);
372 }
373 
374 #define AFU_EVENT_BODY_MAX_SIZE sizeof(struct ocxl_kernel_event_xsl_fault_error)
375 
376 /*
377  * Reports events on the AFU
378  * Format:
379  *	Header (struct ocxl_kernel_event_header)
380  *	Body (struct ocxl_kernel_event_*)
381  *	Header...
382  */
383 static ssize_t afu_read(struct file *file, char __user *buf, size_t count,
384 			loff_t *off)
385 {
386 	struct ocxl_context *ctx = file->private_data;
387 	struct ocxl_kernel_event_header header;
388 	ssize_t rc;
389 	ssize_t used = 0;
390 	DEFINE_WAIT(event_wait);
391 
392 	memset(&header, 0, sizeof(header));
393 
394 	/* Require offset to be 0 */
395 	if (*off != 0)
396 		return -EINVAL;
397 
398 	if (count < (sizeof(struct ocxl_kernel_event_header) +
399 			AFU_EVENT_BODY_MAX_SIZE))
400 		return -EINVAL;
401 
402 	for (;;) {
403 		prepare_to_wait(&ctx->events_wq, &event_wait,
404 				TASK_INTERRUPTIBLE);
405 
406 		if (afu_events_pending(ctx))
407 			break;
408 
409 		if (ctx->status == CLOSED)
410 			break;
411 
412 		if (file->f_flags & O_NONBLOCK) {
413 			finish_wait(&ctx->events_wq, &event_wait);
414 			return -EAGAIN;
415 		}
416 
417 		if (signal_pending(current)) {
418 			finish_wait(&ctx->events_wq, &event_wait);
419 			return -ERESTARTSYS;
420 		}
421 
422 		schedule();
423 	}
424 
425 	finish_wait(&ctx->events_wq, &event_wait);
426 
427 	if (has_xsl_error(ctx)) {
428 		used = append_xsl_error(ctx, &header, buf + sizeof(header));
429 		if (used < 0)
430 			return used;
431 	}
432 
433 	if (!afu_events_pending(ctx))
434 		header.flags |= OCXL_KERNEL_EVENT_FLAG_LAST;
435 
436 	if (copy_to_user(buf, &header, sizeof(header)))
437 		return -EFAULT;
438 
439 	used += sizeof(header);
440 
441 	rc = used;
442 	return rc;
443 }
444 
445 static int afu_release(struct inode *inode, struct file *file)
446 {
447 	struct ocxl_context *ctx = file->private_data;
448 	int rc;
449 
450 	pr_debug("%s for device %x\n", __func__, inode->i_rdev);
451 	rc = ocxl_context_detach(ctx);
452 	mutex_lock(&ctx->mapping_lock);
453 	ctx->mapping = NULL;
454 	mutex_unlock(&ctx->mapping_lock);
455 	wake_up_all(&ctx->events_wq);
456 	if (rc != -EBUSY)
457 		ocxl_context_free(ctx);
458 	return 0;
459 }
460 
461 static const struct file_operations ocxl_afu_fops = {
462 	.owner		= THIS_MODULE,
463 	.open           = afu_open,
464 	.unlocked_ioctl = afu_ioctl,
465 	.compat_ioctl   = afu_compat_ioctl,
466 	.mmap           = afu_mmap,
467 	.poll           = afu_poll,
468 	.read           = afu_read,
469 	.release        = afu_release,
470 };
471 
472 int ocxl_create_cdev(struct ocxl_afu *afu)
473 {
474 	int rc;
475 
476 	cdev_init(&afu->cdev, &ocxl_afu_fops);
477 	rc = cdev_add(&afu->cdev, afu->dev.devt, 1);
478 	if (rc) {
479 		dev_err(&afu->dev, "Unable to add afu char device: %d\n", rc);
480 		return rc;
481 	}
482 	return 0;
483 }
484 
485 void ocxl_destroy_cdev(struct ocxl_afu *afu)
486 {
487 	cdev_del(&afu->cdev);
488 }
489 
490 int ocxl_register_afu(struct ocxl_afu *afu)
491 {
492 	int minor;
493 
494 	minor = allocate_afu_minor(afu);
495 	if (minor < 0)
496 		return minor;
497 	afu->dev.devt = MKDEV(MAJOR(ocxl_dev), minor);
498 	afu->dev.class = ocxl_class;
499 	return device_register(&afu->dev);
500 }
501 
502 void ocxl_unregister_afu(struct ocxl_afu *afu)
503 {
504 	free_afu_minor(afu);
505 }
506 
507 static char *ocxl_devnode(struct device *dev, umode_t *mode)
508 {
509 	return kasprintf(GFP_KERNEL, "ocxl/%s", dev_name(dev));
510 }
511 
512 int ocxl_file_init(void)
513 {
514 	int rc;
515 
516 	mutex_init(&minors_idr_lock);
517 	idr_init(&minors_idr);
518 
519 	rc = alloc_chrdev_region(&ocxl_dev, 0, OCXL_NUM_MINORS, "ocxl");
520 	if (rc) {
521 		pr_err("Unable to allocate ocxl major number: %d\n", rc);
522 		return rc;
523 	}
524 
525 	ocxl_class = class_create(THIS_MODULE, "ocxl");
526 	if (IS_ERR(ocxl_class)) {
527 		pr_err("Unable to create ocxl class\n");
528 		unregister_chrdev_region(ocxl_dev, OCXL_NUM_MINORS);
529 		return PTR_ERR(ocxl_class);
530 	}
531 
532 	ocxl_class->devnode = ocxl_devnode;
533 	return 0;
534 }
535 
536 void ocxl_file_exit(void)
537 {
538 	class_destroy(ocxl_class);
539 	unregister_chrdev_region(ocxl_dev, OCXL_NUM_MINORS);
540 	idr_destroy(&minors_idr);
541 }
542