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