xref: /linux/drivers/misc/ocxl/file.c (revision 24b10e5f8e0d2bee1a10fc67011ea5d936c1a389) 
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/eventfd.h>
7 #include <linux/uaccess.h>
8 #include <uapi/misc/ocxl.h>
9 #include <asm/reg.h>
10 #include <asm/switch_to.h>
11 #include "ocxl_internal.h"
12 
13 
14 #define OCXL_NUM_MINORS 256 /* Total to reserve */
15 
16 static dev_t ocxl_dev;
17 static DEFINE_MUTEX(minors_idr_lock);
18 static struct idr minors_idr;
19 
20 static struct ocxl_file_info *find_and_get_file_info(dev_t devno)
21 {
22 	struct ocxl_file_info *info;
23 
24 	mutex_lock(&minors_idr_lock);
25 	info = idr_find(&minors_idr, MINOR(devno));
26 	if (info)
27 		get_device(&info->dev);
28 	mutex_unlock(&minors_idr_lock);
29 	return info;
30 }
31 
32 static int allocate_minor(struct ocxl_file_info *info)
33 {
34 	int minor;
35 
36 	mutex_lock(&minors_idr_lock);
37 	minor = idr_alloc(&minors_idr, info, 0, OCXL_NUM_MINORS, GFP_KERNEL);
38 	mutex_unlock(&minors_idr_lock);
39 	return minor;
40 }
41 
42 static void free_minor(struct ocxl_file_info *info)
43 {
44 	mutex_lock(&minors_idr_lock);
45 	idr_remove(&minors_idr, MINOR(info->dev.devt));
46 	mutex_unlock(&minors_idr_lock);
47 }
48 
49 static int afu_open(struct inode *inode, struct file *file)
50 {
51 	struct ocxl_file_info *info;
52 	struct ocxl_context *ctx;
53 	int rc;
54 
55 	pr_debug("%s for device %x\n", __func__, inode->i_rdev);
56 
57 	info = find_and_get_file_info(inode->i_rdev);
58 	if (!info)
59 		return -ENODEV;
60 
61 	rc = ocxl_context_alloc(&ctx, info->afu, inode->i_mapping);
62 	if (rc) {
63 		put_device(&info->dev);
64 		return rc;
65 	}
66 	put_device(&info->dev);
67 	file->private_data = ctx;
68 	return 0;
69 }
70 
71 static long afu_ioctl_attach(struct ocxl_context *ctx,
72 			struct ocxl_ioctl_attach __user *uarg)
73 {
74 	struct ocxl_ioctl_attach arg;
75 	u64 amr = 0;
76 
77 	pr_debug("%s for context %d\n", __func__, ctx->pasid);
78 
79 	if (copy_from_user(&arg, uarg, sizeof(arg)))
80 		return -EFAULT;
81 
82 	/* Make sure reserved fields are not set for forward compatibility */
83 	if (arg.reserved1 || arg.reserved2 || arg.reserved3)
84 		return -EINVAL;
85 
86 	amr = arg.amr & mfspr(SPRN_UAMOR);
87 	return ocxl_context_attach(ctx, amr, current->mm);
88 }
89 
90 static long afu_ioctl_get_metadata(struct ocxl_context *ctx,
91 		struct ocxl_ioctl_metadata __user *uarg)
92 {
93 	struct ocxl_ioctl_metadata arg;
94 
95 	memset(&arg, 0, sizeof(arg));
96 
97 	arg.version = 0;
98 
99 	arg.afu_version_major = ctx->afu->config.version_major;
100 	arg.afu_version_minor = ctx->afu->config.version_minor;
101 	arg.pasid = ctx->pasid;
102 	arg.pp_mmio_size = ctx->afu->config.pp_mmio_stride;
103 	arg.global_mmio_size = ctx->afu->config.global_mmio_size;
104 
105 	if (copy_to_user(uarg, &arg, sizeof(arg)))
106 		return -EFAULT;
107 
108 	return 0;
109 }
110 
111 #ifdef CONFIG_PPC64
112 static long afu_ioctl_enable_p9_wait(struct ocxl_context *ctx,
113 		struct ocxl_ioctl_p9_wait __user *uarg)
114 {
115 	struct ocxl_ioctl_p9_wait arg;
116 
117 	memset(&arg, 0, sizeof(arg));
118 
119 	if (cpu_has_feature(CPU_FTR_P9_TIDR)) {
120 		enum ocxl_context_status status;
121 
122 		// Locks both status & tidr
123 		mutex_lock(&ctx->status_mutex);
124 		if (!ctx->tidr) {
125 			if (set_thread_tidr(current)) {
126 				mutex_unlock(&ctx->status_mutex);
127 				return -ENOENT;
128 			}
129 
130 			ctx->tidr = current->thread.tidr;
131 		}
132 
133 		status = ctx->status;
134 		mutex_unlock(&ctx->status_mutex);
135 
136 		if (status == ATTACHED) {
137 			int rc = ocxl_link_update_pe(ctx->afu->fn->link,
138 				ctx->pasid, ctx->tidr);
139 
140 			if (rc)
141 				return rc;
142 		}
143 
144 		arg.thread_id = ctx->tidr;
145 	} else
146 		return -ENOENT;
147 
148 	if (copy_to_user(uarg, &arg, sizeof(arg)))
149 		return -EFAULT;
150 
151 	return 0;
152 }
153 #endif
154 
155 
156 static long afu_ioctl_get_features(struct ocxl_context *ctx,
157 		struct ocxl_ioctl_features __user *uarg)
158 {
159 	struct ocxl_ioctl_features arg;
160 
161 	memset(&arg, 0, sizeof(arg));
162 
163 #ifdef CONFIG_PPC64
164 	if (cpu_has_feature(CPU_FTR_P9_TIDR))
165 		arg.flags[0] |= OCXL_IOCTL_FEATURES_FLAGS0_P9_WAIT;
166 #endif
167 
168 	if (copy_to_user(uarg, &arg, sizeof(arg)))
169 		return -EFAULT;
170 
171 	return 0;
172 }
173 
174 #define CMD_STR(x) (x == OCXL_IOCTL_ATTACH ? "ATTACH" :			\
175 			x == OCXL_IOCTL_IRQ_ALLOC ? "IRQ_ALLOC" :	\
176 			x == OCXL_IOCTL_IRQ_FREE ? "IRQ_FREE" :		\
177 			x == OCXL_IOCTL_IRQ_SET_FD ? "IRQ_SET_FD" :	\
178 			x == OCXL_IOCTL_GET_METADATA ? "GET_METADATA" :	\
179 			x == OCXL_IOCTL_ENABLE_P9_WAIT ? "ENABLE_P9_WAIT" :	\
180 			x == OCXL_IOCTL_GET_FEATURES ? "GET_FEATURES" :	\
181 			"UNKNOWN")
182 
183 static irqreturn_t irq_handler(void *private)
184 {
185 	struct eventfd_ctx *ev_ctx = private;
186 
187 	eventfd_signal(ev_ctx);
188 	return IRQ_HANDLED;
189 }
190 
191 static void irq_free(void *private)
192 {
193 	struct eventfd_ctx *ev_ctx = private;
194 
195 	eventfd_ctx_put(ev_ctx);
196 }
197 
198 static long afu_ioctl(struct file *file, unsigned int cmd,
199 		unsigned long args)
200 {
201 	struct ocxl_context *ctx = file->private_data;
202 	struct ocxl_ioctl_irq_fd irq_fd;
203 	struct eventfd_ctx *ev_ctx;
204 	int irq_id;
205 	u64 irq_offset;
206 	long rc;
207 	bool closed;
208 
209 	pr_debug("%s for context %d, command %s\n", __func__, ctx->pasid,
210 		CMD_STR(cmd));
211 
212 	mutex_lock(&ctx->status_mutex);
213 	closed = (ctx->status == CLOSED);
214 	mutex_unlock(&ctx->status_mutex);
215 
216 	if (closed)
217 		return -EIO;
218 
219 	switch (cmd) {
220 	case OCXL_IOCTL_ATTACH:
221 		rc = afu_ioctl_attach(ctx,
222 				(struct ocxl_ioctl_attach __user *) args);
223 		break;
224 
225 	case OCXL_IOCTL_IRQ_ALLOC:
226 		rc = ocxl_afu_irq_alloc(ctx, &irq_id);
227 		if (!rc) {
228 			irq_offset = ocxl_irq_id_to_offset(ctx, irq_id);
229 			rc = copy_to_user((u64 __user *) args, &irq_offset,
230 					sizeof(irq_offset));
231 			if (rc) {
232 				ocxl_afu_irq_free(ctx, irq_id);
233 				return -EFAULT;
234 			}
235 		}
236 		break;
237 
238 	case OCXL_IOCTL_IRQ_FREE:
239 		rc = copy_from_user(&irq_offset, (u64 __user *) args,
240 				sizeof(irq_offset));
241 		if (rc)
242 			return -EFAULT;
243 		irq_id = ocxl_irq_offset_to_id(ctx, irq_offset);
244 		rc = ocxl_afu_irq_free(ctx, irq_id);
245 		break;
246 
247 	case OCXL_IOCTL_IRQ_SET_FD:
248 		rc = copy_from_user(&irq_fd, (u64 __user *) args,
249 				sizeof(irq_fd));
250 		if (rc)
251 			return -EFAULT;
252 		if (irq_fd.reserved)
253 			return -EINVAL;
254 		irq_id = ocxl_irq_offset_to_id(ctx, irq_fd.irq_offset);
255 		ev_ctx = eventfd_ctx_fdget(irq_fd.eventfd);
256 		if (IS_ERR(ev_ctx))
257 			return PTR_ERR(ev_ctx);
258 		rc = ocxl_irq_set_handler(ctx, irq_id, irq_handler, irq_free, ev_ctx);
259 		if (rc)
260 			eventfd_ctx_put(ev_ctx);
261 		break;
262 
263 	case OCXL_IOCTL_GET_METADATA:
264 		rc = afu_ioctl_get_metadata(ctx,
265 				(struct ocxl_ioctl_metadata __user *) args);
266 		break;
267 
268 #ifdef CONFIG_PPC64
269 	case OCXL_IOCTL_ENABLE_P9_WAIT:
270 		rc = afu_ioctl_enable_p9_wait(ctx,
271 				(struct ocxl_ioctl_p9_wait __user *) args);
272 		break;
273 #endif
274 
275 	case OCXL_IOCTL_GET_FEATURES:
276 		rc = afu_ioctl_get_features(ctx,
277 				(struct ocxl_ioctl_features __user *) args);
278 		break;
279 
280 	default:
281 		rc = -EINVAL;
282 	}
283 	return rc;
284 }
285 
286 static long afu_compat_ioctl(struct file *file, unsigned int cmd,
287 			unsigned long args)
288 {
289 	return afu_ioctl(file, cmd, args);
290 }
291 
292 static int afu_mmap(struct file *file, struct vm_area_struct *vma)
293 {
294 	struct ocxl_context *ctx = file->private_data;
295 
296 	pr_debug("%s for context %d\n", __func__, ctx->pasid);
297 	return ocxl_context_mmap(ctx, vma);
298 }
299 
300 static bool has_xsl_error(struct ocxl_context *ctx)
301 {
302 	bool ret;
303 
304 	mutex_lock(&ctx->xsl_error_lock);
305 	ret = !!ctx->xsl_error.addr;
306 	mutex_unlock(&ctx->xsl_error_lock);
307 
308 	return ret;
309 }
310 
311 /*
312  * Are there any events pending on the AFU
313  * ctx: The AFU context
314  * Returns: true if there are events pending
315  */
316 static bool afu_events_pending(struct ocxl_context *ctx)
317 {
318 	if (has_xsl_error(ctx))
319 		return true;
320 	return false;
321 }
322 
323 static unsigned int afu_poll(struct file *file, struct poll_table_struct *wait)
324 {
325 	struct ocxl_context *ctx = file->private_data;
326 	unsigned int mask = 0;
327 	bool closed;
328 
329 	pr_debug("%s for context %d\n", __func__, ctx->pasid);
330 
331 	poll_wait(file, &ctx->events_wq, wait);
332 
333 	mutex_lock(&ctx->status_mutex);
334 	closed = (ctx->status == CLOSED);
335 	mutex_unlock(&ctx->status_mutex);
336 
337 	if (afu_events_pending(ctx))
338 		mask = EPOLLIN | EPOLLRDNORM;
339 	else if (closed)
340 		mask = EPOLLERR;
341 
342 	return mask;
343 }
344 
345 /*
346  * Populate the supplied buffer with a single XSL error
347  * ctx:	The AFU context to report the error from
348  * header: the event header to populate
349  * buf: The buffer to write the body into (should be at least
350  *      AFU_EVENT_BODY_XSL_ERROR_SIZE)
351  * Return: the amount of buffer that was populated
352  */
353 static ssize_t append_xsl_error(struct ocxl_context *ctx,
354 				struct ocxl_kernel_event_header *header,
355 				char __user *buf)
356 {
357 	struct ocxl_kernel_event_xsl_fault_error body;
358 
359 	memset(&body, 0, sizeof(body));
360 
361 	mutex_lock(&ctx->xsl_error_lock);
362 	if (!ctx->xsl_error.addr) {
363 		mutex_unlock(&ctx->xsl_error_lock);
364 		return 0;
365 	}
366 
367 	body.addr = ctx->xsl_error.addr;
368 	body.dsisr = ctx->xsl_error.dsisr;
369 	body.count = ctx->xsl_error.count;
370 
371 	ctx->xsl_error.addr = 0;
372 	ctx->xsl_error.dsisr = 0;
373 	ctx->xsl_error.count = 0;
374 
375 	mutex_unlock(&ctx->xsl_error_lock);
376 
377 	header->type = OCXL_AFU_EVENT_XSL_FAULT_ERROR;
378 
379 	if (copy_to_user(buf, &body, sizeof(body)))
380 		return -EFAULT;
381 
382 	return sizeof(body);
383 }
384 
385 #define AFU_EVENT_BODY_MAX_SIZE sizeof(struct ocxl_kernel_event_xsl_fault_error)
386 
387 /*
388  * Reports events on the AFU
389  * Format:
390  *	Header (struct ocxl_kernel_event_header)
391  *	Body (struct ocxl_kernel_event_*)
392  *	Header...
393  */
394 static ssize_t afu_read(struct file *file, char __user *buf, size_t count,
395 			loff_t *off)
396 {
397 	struct ocxl_context *ctx = file->private_data;
398 	struct ocxl_kernel_event_header header;
399 	ssize_t rc;
400 	ssize_t used = 0;
401 	DEFINE_WAIT(event_wait);
402 
403 	memset(&header, 0, sizeof(header));
404 
405 	/* Require offset to be 0 */
406 	if (*off != 0)
407 		return -EINVAL;
408 
409 	if (count < (sizeof(struct ocxl_kernel_event_header) +
410 			AFU_EVENT_BODY_MAX_SIZE))
411 		return -EINVAL;
412 
413 	for (;;) {
414 		prepare_to_wait(&ctx->events_wq, &event_wait,
415 				TASK_INTERRUPTIBLE);
416 
417 		if (afu_events_pending(ctx))
418 			break;
419 
420 		if (ctx->status == CLOSED)
421 			break;
422 
423 		if (file->f_flags & O_NONBLOCK) {
424 			finish_wait(&ctx->events_wq, &event_wait);
425 			return -EAGAIN;
426 		}
427 
428 		if (signal_pending(current)) {
429 			finish_wait(&ctx->events_wq, &event_wait);
430 			return -ERESTARTSYS;
431 		}
432 
433 		schedule();
434 	}
435 
436 	finish_wait(&ctx->events_wq, &event_wait);
437 
438 	if (has_xsl_error(ctx)) {
439 		used = append_xsl_error(ctx, &header, buf + sizeof(header));
440 		if (used < 0)
441 			return used;
442 	}
443 
444 	if (!afu_events_pending(ctx))
445 		header.flags |= OCXL_KERNEL_EVENT_FLAG_LAST;
446 
447 	if (copy_to_user(buf, &header, sizeof(header)))
448 		return -EFAULT;
449 
450 	used += sizeof(header);
451 
452 	rc = used;
453 	return rc;
454 }
455 
456 static int afu_release(struct inode *inode, struct file *file)
457 {
458 	struct ocxl_context *ctx = file->private_data;
459 	int rc;
460 
461 	pr_debug("%s for device %x\n", __func__, inode->i_rdev);
462 	rc = ocxl_context_detach(ctx);
463 	mutex_lock(&ctx->mapping_lock);
464 	ctx->mapping = NULL;
465 	mutex_unlock(&ctx->mapping_lock);
466 	wake_up_all(&ctx->events_wq);
467 	if (rc != -EBUSY)
468 		ocxl_context_free(ctx);
469 	return 0;
470 }
471 
472 static const struct file_operations ocxl_afu_fops = {
473 	.owner		= THIS_MODULE,
474 	.open           = afu_open,
475 	.unlocked_ioctl = afu_ioctl,
476 	.compat_ioctl   = afu_compat_ioctl,
477 	.mmap           = afu_mmap,
478 	.poll           = afu_poll,
479 	.read           = afu_read,
480 	.release        = afu_release,
481 };
482 
483 // Free the info struct
484 static void info_release(struct device *dev)
485 {
486 	struct ocxl_file_info *info = container_of(dev, struct ocxl_file_info, dev);
487 
488 	ocxl_afu_put(info->afu);
489 	kfree(info);
490 }
491 
492 static int ocxl_file_make_visible(struct ocxl_file_info *info)
493 {
494 	int rc;
495 
496 	cdev_init(&info->cdev, &ocxl_afu_fops);
497 	rc = cdev_add(&info->cdev, info->dev.devt, 1);
498 	if (rc) {
499 		dev_err(&info->dev, "Unable to add afu char device: %d\n", rc);
500 		return rc;
501 	}
502 
503 	return 0;
504 }
505 
506 static void ocxl_file_make_invisible(struct ocxl_file_info *info)
507 {
508 	cdev_del(&info->cdev);
509 }
510 
511 static char *ocxl_devnode(const struct device *dev, umode_t *mode)
512 {
513 	return kasprintf(GFP_KERNEL, "ocxl/%s", dev_name(dev));
514 }
515 
516 static const struct class ocxl_class = {
517 	.name =		"ocxl",
518 	.devnode =	ocxl_devnode,
519 };
520 
521 int ocxl_file_register_afu(struct ocxl_afu *afu)
522 {
523 	int minor;
524 	int rc;
525 	struct ocxl_file_info *info;
526 	struct ocxl_fn *fn = afu->fn;
527 	struct pci_dev *pci_dev = to_pci_dev(fn->dev.parent);
528 
529 	info = kzalloc(sizeof(*info), GFP_KERNEL);
530 	if (info == NULL)
531 		return -ENOMEM;
532 
533 	minor = allocate_minor(info);
534 	if (minor < 0) {
535 		kfree(info);
536 		return minor;
537 	}
538 
539 	info->dev.parent = &fn->dev;
540 	info->dev.devt = MKDEV(MAJOR(ocxl_dev), minor);
541 	info->dev.class = &ocxl_class;
542 	info->dev.release = info_release;
543 
544 	info->afu = afu;
545 	ocxl_afu_get(afu);
546 
547 	rc = dev_set_name(&info->dev, "%s.%s.%hhu",
548 		afu->config.name, dev_name(&pci_dev->dev), afu->config.idx);
549 	if (rc)
550 		goto err_put;
551 
552 	rc = device_register(&info->dev);
553 	if (rc) {
554 		free_minor(info);
555 		put_device(&info->dev);
556 		return rc;
557 	}
558 
559 	rc = ocxl_sysfs_register_afu(info);
560 	if (rc)
561 		goto err_unregister;
562 
563 	rc = ocxl_file_make_visible(info);
564 	if (rc)
565 		goto err_unregister;
566 
567 	ocxl_afu_set_private(afu, info);
568 
569 	return 0;
570 
571 err_unregister:
572 	ocxl_sysfs_unregister_afu(info); // safe to call even if register failed
573 	free_minor(info);
574 	device_unregister(&info->dev);
575 	return rc;
576 err_put:
577 	ocxl_afu_put(afu);
578 	free_minor(info);
579 	kfree(info);
580 	return rc;
581 }
582 
583 void ocxl_file_unregister_afu(struct ocxl_afu *afu)
584 {
585 	struct ocxl_file_info *info = ocxl_afu_get_private(afu);
586 
587 	if (!info)
588 		return;
589 
590 	ocxl_file_make_invisible(info);
591 	ocxl_sysfs_unregister_afu(info);
592 	free_minor(info);
593 	device_unregister(&info->dev);
594 }
595 
596 int ocxl_file_init(void)
597 {
598 	int rc;
599 
600 	idr_init(&minors_idr);
601 
602 	rc = alloc_chrdev_region(&ocxl_dev, 0, OCXL_NUM_MINORS, "ocxl");
603 	if (rc) {
604 		pr_err("Unable to allocate ocxl major number: %d\n", rc);
605 		return rc;
606 	}
607 
608 	rc = class_register(&ocxl_class);
609 	if (rc) {
610 		pr_err("Unable to create ocxl class\n");
611 		unregister_chrdev_region(ocxl_dev, OCXL_NUM_MINORS);
612 		return rc;
613 	}
614 
615 	return 0;
616 }
617 
618 void ocxl_file_exit(void)
619 {
620 	class_unregister(&ocxl_class);
621 	unregister_chrdev_region(ocxl_dev, OCXL_NUM_MINORS);
622 	idr_destroy(&minors_idr);
623 }
624