xref: /openbmc/linux/drivers/misc/cxl/file.c (revision bc5aa3a0)
1 /*
2  * Copyright 2014 IBM Corp.
3  *
4  * This program is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU General Public License
6  * as published by the Free Software Foundation; either version
7  * 2 of the License, or (at your option) any later version.
8  */
9 
10 #include <linux/spinlock.h>
11 #include <linux/module.h>
12 #include <linux/export.h>
13 #include <linux/kernel.h>
14 #include <linux/bitmap.h>
15 #include <linux/sched.h>
16 #include <linux/poll.h>
17 #include <linux/pid.h>
18 #include <linux/fs.h>
19 #include <linux/mm.h>
20 #include <linux/slab.h>
21 #include <asm/cputable.h>
22 #include <asm/current.h>
23 #include <asm/copro.h>
24 
25 #include "cxl.h"
26 #include "trace.h"
27 
28 #define CXL_NUM_MINORS 256 /* Total to reserve */
29 
30 #define CXL_AFU_MINOR_D(afu) (CXL_CARD_MINOR(afu->adapter) + 1 + (3 * afu->slice))
31 #define CXL_AFU_MINOR_M(afu) (CXL_AFU_MINOR_D(afu) + 1)
32 #define CXL_AFU_MINOR_S(afu) (CXL_AFU_MINOR_D(afu) + 2)
33 #define CXL_AFU_MKDEV_D(afu) MKDEV(MAJOR(cxl_dev), CXL_AFU_MINOR_D(afu))
34 #define CXL_AFU_MKDEV_M(afu) MKDEV(MAJOR(cxl_dev), CXL_AFU_MINOR_M(afu))
35 #define CXL_AFU_MKDEV_S(afu) MKDEV(MAJOR(cxl_dev), CXL_AFU_MINOR_S(afu))
36 
37 #define CXL_DEVT_AFU(dev) ((MINOR(dev) % CXL_DEV_MINORS - 1) / 3)
38 
39 #define CXL_DEVT_IS_CARD(dev) (MINOR(dev) % CXL_DEV_MINORS == 0)
40 
41 static dev_t cxl_dev;
42 
43 static struct class *cxl_class;
44 
45 static int __afu_open(struct inode *inode, struct file *file, bool master)
46 {
47 	struct cxl *adapter;
48 	struct cxl_afu *afu;
49 	struct cxl_context *ctx;
50 	int adapter_num = CXL_DEVT_ADAPTER(inode->i_rdev);
51 	int slice = CXL_DEVT_AFU(inode->i_rdev);
52 	int rc = -ENODEV;
53 
54 	pr_devel("afu_open afu%i.%i\n", slice, adapter_num);
55 
56 	if (!(adapter = get_cxl_adapter(adapter_num)))
57 		return -ENODEV;
58 
59 	if (slice > adapter->slices)
60 		goto err_put_adapter;
61 
62 	spin_lock(&adapter->afu_list_lock);
63 	if (!(afu = adapter->afu[slice])) {
64 		spin_unlock(&adapter->afu_list_lock);
65 		goto err_put_adapter;
66 	}
67 
68 	/*
69 	 * taking a ref to the afu so that it doesn't go away
70 	 * for rest of the function. This ref is released before
71 	 * we return.
72 	 */
73 	cxl_afu_get(afu);
74 	spin_unlock(&adapter->afu_list_lock);
75 
76 	if (!afu->current_mode)
77 		goto err_put_afu;
78 
79 	if (!cxl_ops->link_ok(adapter, afu)) {
80 		rc = -EIO;
81 		goto err_put_afu;
82 	}
83 
84 	if (!(ctx = cxl_context_alloc())) {
85 		rc = -ENOMEM;
86 		goto err_put_afu;
87 	}
88 
89 	if ((rc = cxl_context_init(ctx, afu, master, inode->i_mapping)))
90 		goto err_put_afu;
91 
92 	pr_devel("afu_open pe: %i\n", ctx->pe);
93 	file->private_data = ctx;
94 	cxl_ctx_get();
95 
96 	/* indicate success */
97 	rc = 0;
98 
99 err_put_afu:
100 	/* release the ref taken earlier */
101 	cxl_afu_put(afu);
102 err_put_adapter:
103 	put_device(&adapter->dev);
104 	return rc;
105 }
106 
107 int afu_open(struct inode *inode, struct file *file)
108 {
109 	return __afu_open(inode, file, false);
110 }
111 
112 static int afu_master_open(struct inode *inode, struct file *file)
113 {
114 	return __afu_open(inode, file, true);
115 }
116 
117 int afu_release(struct inode *inode, struct file *file)
118 {
119 	struct cxl_context *ctx = file->private_data;
120 
121 	pr_devel("%s: closing cxl file descriptor. pe: %i\n",
122 		 __func__, ctx->pe);
123 	cxl_context_detach(ctx);
124 
125 
126 	/*
127 	 * Delete the context's mapping pointer, unless it's created by the
128 	 * kernel API, in which case leave it so it can be freed by reclaim_ctx()
129 	 */
130 	if (!ctx->kernelapi) {
131 		mutex_lock(&ctx->mapping_lock);
132 		ctx->mapping = NULL;
133 		mutex_unlock(&ctx->mapping_lock);
134 	}
135 
136 	/*
137 	 * At this this point all bottom halfs have finished and we should be
138 	 * getting no more IRQs from the hardware for this context.  Once it's
139 	 * removed from the IDR (and RCU synchronised) it's safe to free the
140 	 * sstp and context.
141 	 */
142 	cxl_context_free(ctx);
143 
144 	return 0;
145 }
146 
147 static long afu_ioctl_start_work(struct cxl_context *ctx,
148 				 struct cxl_ioctl_start_work __user *uwork)
149 {
150 	struct cxl_ioctl_start_work work;
151 	u64 amr = 0;
152 	int rc;
153 
154 	pr_devel("%s: pe: %i\n", __func__, ctx->pe);
155 
156 	/* Do this outside the status_mutex to avoid a circular dependency with
157 	 * the locking in cxl_mmap_fault() */
158 	if (copy_from_user(&work, uwork,
159 			   sizeof(struct cxl_ioctl_start_work))) {
160 		rc = -EFAULT;
161 		goto out;
162 	}
163 
164 	mutex_lock(&ctx->status_mutex);
165 	if (ctx->status != OPENED) {
166 		rc = -EIO;
167 		goto out;
168 	}
169 
170 	/*
171 	 * if any of the reserved fields are set or any of the unused
172 	 * flags are set it's invalid
173 	 */
174 	if (work.reserved1 || work.reserved2 || work.reserved3 ||
175 	    work.reserved4 || work.reserved5 || work.reserved6 ||
176 	    (work.flags & ~CXL_START_WORK_ALL)) {
177 		rc = -EINVAL;
178 		goto out;
179 	}
180 
181 	if (!(work.flags & CXL_START_WORK_NUM_IRQS))
182 		work.num_interrupts = ctx->afu->pp_irqs;
183 	else if ((work.num_interrupts < ctx->afu->pp_irqs) ||
184 		 (work.num_interrupts > ctx->afu->irqs_max)) {
185 		rc =  -EINVAL;
186 		goto out;
187 	}
188 	if ((rc = afu_register_irqs(ctx, work.num_interrupts)))
189 		goto out;
190 
191 	if (work.flags & CXL_START_WORK_AMR)
192 		amr = work.amr & mfspr(SPRN_UAMOR);
193 
194 	ctx->mmio_err_ff = !!(work.flags & CXL_START_WORK_ERR_FF);
195 
196 	/*
197 	 * We grab the PID here and not in the file open to allow for the case
198 	 * where a process (master, some daemon, etc) has opened the chardev on
199 	 * behalf of another process, so the AFU's mm gets bound to the process
200 	 * that performs this ioctl and not the process that opened the file.
201 	 * Also we grab the PID of the group leader so that if the task that
202 	 * has performed the attach operation exits the mm context of the
203 	 * process is still accessible.
204 	 */
205 	ctx->pid = get_task_pid(current, PIDTYPE_PID);
206 	ctx->glpid = get_task_pid(current->group_leader, PIDTYPE_PID);
207 
208 	trace_cxl_attach(ctx, work.work_element_descriptor, work.num_interrupts, amr);
209 
210 	if ((rc = cxl_ops->attach_process(ctx, false, work.work_element_descriptor,
211 							amr))) {
212 		afu_release_irqs(ctx, ctx);
213 		goto out;
214 	}
215 
216 	ctx->status = STARTED;
217 	rc = 0;
218 out:
219 	mutex_unlock(&ctx->status_mutex);
220 	return rc;
221 }
222 
223 static long afu_ioctl_process_element(struct cxl_context *ctx,
224 				      int __user *upe)
225 {
226 	pr_devel("%s: pe: %i\n", __func__, ctx->pe);
227 
228 	if (copy_to_user(upe, &ctx->external_pe, sizeof(__u32)))
229 		return -EFAULT;
230 
231 	return 0;
232 }
233 
234 static long afu_ioctl_get_afu_id(struct cxl_context *ctx,
235 				 struct cxl_afu_id __user *upafuid)
236 {
237 	struct cxl_afu_id afuid = { 0 };
238 
239 	afuid.card_id = ctx->afu->adapter->adapter_num;
240 	afuid.afu_offset = ctx->afu->slice;
241 	afuid.afu_mode = ctx->afu->current_mode;
242 
243 	/* set the flag bit in case the afu is a slave */
244 	if (ctx->afu->current_mode == CXL_MODE_DIRECTED && !ctx->master)
245 		afuid.flags |= CXL_AFUID_FLAG_SLAVE;
246 
247 	if (copy_to_user(upafuid, &afuid, sizeof(afuid)))
248 		return -EFAULT;
249 
250 	return 0;
251 }
252 
253 long afu_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
254 {
255 	struct cxl_context *ctx = file->private_data;
256 
257 	if (ctx->status == CLOSED)
258 		return -EIO;
259 
260 	if (!cxl_ops->link_ok(ctx->afu->adapter, ctx->afu))
261 		return -EIO;
262 
263 	pr_devel("afu_ioctl\n");
264 	switch (cmd) {
265 	case CXL_IOCTL_START_WORK:
266 		return afu_ioctl_start_work(ctx, (struct cxl_ioctl_start_work __user *)arg);
267 	case CXL_IOCTL_GET_PROCESS_ELEMENT:
268 		return afu_ioctl_process_element(ctx, (__u32 __user *)arg);
269 	case CXL_IOCTL_GET_AFU_ID:
270 		return afu_ioctl_get_afu_id(ctx, (struct cxl_afu_id __user *)
271 					    arg);
272 	}
273 	return -EINVAL;
274 }
275 
276 static long afu_compat_ioctl(struct file *file, unsigned int cmd,
277 			     unsigned long arg)
278 {
279 	return afu_ioctl(file, cmd, arg);
280 }
281 
282 int afu_mmap(struct file *file, struct vm_area_struct *vm)
283 {
284 	struct cxl_context *ctx = file->private_data;
285 
286 	/* AFU must be started before we can MMIO */
287 	if (ctx->status != STARTED)
288 		return -EIO;
289 
290 	if (!cxl_ops->link_ok(ctx->afu->adapter, ctx->afu))
291 		return -EIO;
292 
293 	return cxl_context_iomap(ctx, vm);
294 }
295 
296 static inline bool ctx_event_pending(struct cxl_context *ctx)
297 {
298 	if (ctx->pending_irq || ctx->pending_fault || ctx->pending_afu_err)
299 		return true;
300 
301 	if (ctx->afu_driver_ops && atomic_read(&ctx->afu_driver_events))
302 		return true;
303 
304 	return false;
305 }
306 
307 unsigned int afu_poll(struct file *file, struct poll_table_struct *poll)
308 {
309 	struct cxl_context *ctx = file->private_data;
310 	int mask = 0;
311 	unsigned long flags;
312 
313 
314 	poll_wait(file, &ctx->wq, poll);
315 
316 	pr_devel("afu_poll wait done pe: %i\n", ctx->pe);
317 
318 	spin_lock_irqsave(&ctx->lock, flags);
319 	if (ctx_event_pending(ctx))
320 		mask |= POLLIN | POLLRDNORM;
321 	else if (ctx->status == CLOSED)
322 		/* Only error on closed when there are no futher events pending
323 		 */
324 		mask |= POLLERR;
325 	spin_unlock_irqrestore(&ctx->lock, flags);
326 
327 	pr_devel("afu_poll pe: %i returning %#x\n", ctx->pe, mask);
328 
329 	return mask;
330 }
331 
332 static ssize_t afu_driver_event_copy(struct cxl_context *ctx,
333 				     char __user *buf,
334 				     struct cxl_event *event,
335 				     struct cxl_event_afu_driver_reserved *pl)
336 {
337 	/* Check event */
338 	if (!pl) {
339 		ctx->afu_driver_ops->event_delivered(ctx, pl, -EINVAL);
340 		return -EFAULT;
341 	}
342 
343 	/* Check event size */
344 	event->header.size += pl->data_size;
345 	if (event->header.size > CXL_READ_MIN_SIZE) {
346 		ctx->afu_driver_ops->event_delivered(ctx, pl, -EINVAL);
347 		return -EFAULT;
348 	}
349 
350 	/* Copy event header */
351 	if (copy_to_user(buf, event, sizeof(struct cxl_event_header))) {
352 		ctx->afu_driver_ops->event_delivered(ctx, pl, -EFAULT);
353 		return -EFAULT;
354 	}
355 
356 	/* Copy event data */
357 	buf += sizeof(struct cxl_event_header);
358 	if (copy_to_user(buf, &pl->data, pl->data_size)) {
359 		ctx->afu_driver_ops->event_delivered(ctx, pl, -EFAULT);
360 		return -EFAULT;
361 	}
362 
363 	ctx->afu_driver_ops->event_delivered(ctx, pl, 0); /* Success */
364 	return event->header.size;
365 }
366 
367 ssize_t afu_read(struct file *file, char __user *buf, size_t count,
368 			loff_t *off)
369 {
370 	struct cxl_context *ctx = file->private_data;
371 	struct cxl_event_afu_driver_reserved *pl = NULL;
372 	struct cxl_event event;
373 	unsigned long flags;
374 	int rc;
375 	DEFINE_WAIT(wait);
376 
377 	if (!cxl_ops->link_ok(ctx->afu->adapter, ctx->afu))
378 		return -EIO;
379 
380 	if (count < CXL_READ_MIN_SIZE)
381 		return -EINVAL;
382 
383 	spin_lock_irqsave(&ctx->lock, flags);
384 
385 	for (;;) {
386 		prepare_to_wait(&ctx->wq, &wait, TASK_INTERRUPTIBLE);
387 		if (ctx_event_pending(ctx) || (ctx->status == CLOSED))
388 			break;
389 
390 		if (!cxl_ops->link_ok(ctx->afu->adapter, ctx->afu)) {
391 			rc = -EIO;
392 			goto out;
393 		}
394 
395 		if (file->f_flags & O_NONBLOCK) {
396 			rc = -EAGAIN;
397 			goto out;
398 		}
399 
400 		if (signal_pending(current)) {
401 			rc = -ERESTARTSYS;
402 			goto out;
403 		}
404 
405 		spin_unlock_irqrestore(&ctx->lock, flags);
406 		pr_devel("afu_read going to sleep...\n");
407 		schedule();
408 		pr_devel("afu_read woken up\n");
409 		spin_lock_irqsave(&ctx->lock, flags);
410 	}
411 
412 	finish_wait(&ctx->wq, &wait);
413 
414 	memset(&event, 0, sizeof(event));
415 	event.header.process_element = ctx->pe;
416 	event.header.size = sizeof(struct cxl_event_header);
417 	if (ctx->afu_driver_ops && atomic_read(&ctx->afu_driver_events)) {
418 		pr_devel("afu_read delivering AFU driver specific event\n");
419 		pl = ctx->afu_driver_ops->fetch_event(ctx);
420 		atomic_dec(&ctx->afu_driver_events);
421 		event.header.type = CXL_EVENT_AFU_DRIVER;
422 	} else if (ctx->pending_irq) {
423 		pr_devel("afu_read delivering AFU interrupt\n");
424 		event.header.size += sizeof(struct cxl_event_afu_interrupt);
425 		event.header.type = CXL_EVENT_AFU_INTERRUPT;
426 		event.irq.irq = find_first_bit(ctx->irq_bitmap, ctx->irq_count) + 1;
427 		clear_bit(event.irq.irq - 1, ctx->irq_bitmap);
428 		if (bitmap_empty(ctx->irq_bitmap, ctx->irq_count))
429 			ctx->pending_irq = false;
430 	} else if (ctx->pending_fault) {
431 		pr_devel("afu_read delivering data storage fault\n");
432 		event.header.size += sizeof(struct cxl_event_data_storage);
433 		event.header.type = CXL_EVENT_DATA_STORAGE;
434 		event.fault.addr = ctx->fault_addr;
435 		event.fault.dsisr = ctx->fault_dsisr;
436 		ctx->pending_fault = false;
437 	} else if (ctx->pending_afu_err) {
438 		pr_devel("afu_read delivering afu error\n");
439 		event.header.size += sizeof(struct cxl_event_afu_error);
440 		event.header.type = CXL_EVENT_AFU_ERROR;
441 		event.afu_error.error = ctx->afu_err;
442 		ctx->pending_afu_err = false;
443 	} else if (ctx->status == CLOSED) {
444 		pr_devel("afu_read fatal error\n");
445 		spin_unlock_irqrestore(&ctx->lock, flags);
446 		return -EIO;
447 	} else
448 		WARN(1, "afu_read must be buggy\n");
449 
450 	spin_unlock_irqrestore(&ctx->lock, flags);
451 
452 	if (event.header.type == CXL_EVENT_AFU_DRIVER)
453 		return afu_driver_event_copy(ctx, buf, &event, pl);
454 
455 	if (copy_to_user(buf, &event, event.header.size))
456 		return -EFAULT;
457 	return event.header.size;
458 
459 out:
460 	finish_wait(&ctx->wq, &wait);
461 	spin_unlock_irqrestore(&ctx->lock, flags);
462 	return rc;
463 }
464 
465 /*
466  * Note: if this is updated, we need to update api.c to patch the new ones in
467  * too
468  */
469 const struct file_operations afu_fops = {
470 	.owner		= THIS_MODULE,
471 	.open           = afu_open,
472 	.poll		= afu_poll,
473 	.read		= afu_read,
474 	.release        = afu_release,
475 	.unlocked_ioctl = afu_ioctl,
476 	.compat_ioctl   = afu_compat_ioctl,
477 	.mmap           = afu_mmap,
478 };
479 
480 static const struct file_operations afu_master_fops = {
481 	.owner		= THIS_MODULE,
482 	.open           = afu_master_open,
483 	.poll		= afu_poll,
484 	.read		= afu_read,
485 	.release        = afu_release,
486 	.unlocked_ioctl = afu_ioctl,
487 	.compat_ioctl   = afu_compat_ioctl,
488 	.mmap           = afu_mmap,
489 };
490 
491 
492 static char *cxl_devnode(struct device *dev, umode_t *mode)
493 {
494 	if (cpu_has_feature(CPU_FTR_HVMODE) &&
495 	    CXL_DEVT_IS_CARD(dev->devt)) {
496 		/*
497 		 * These minor numbers will eventually be used to program the
498 		 * PSL and AFUs once we have dynamic reprogramming support
499 		 */
500 		return NULL;
501 	}
502 	return kasprintf(GFP_KERNEL, "cxl/%s", dev_name(dev));
503 }
504 
505 extern struct class *cxl_class;
506 
507 static int cxl_add_chardev(struct cxl_afu *afu, dev_t devt, struct cdev *cdev,
508 			   struct device **chardev, char *postfix, char *desc,
509 			   const struct file_operations *fops)
510 {
511 	struct device *dev;
512 	int rc;
513 
514 	cdev_init(cdev, fops);
515 	if ((rc = cdev_add(cdev, devt, 1))) {
516 		dev_err(&afu->dev, "Unable to add %s chardev: %i\n", desc, rc);
517 		return rc;
518 	}
519 
520 	dev = device_create(cxl_class, &afu->dev, devt, afu,
521 			"afu%i.%i%s", afu->adapter->adapter_num, afu->slice, postfix);
522 	if (IS_ERR(dev)) {
523 		dev_err(&afu->dev, "Unable to create %s chardev in sysfs: %i\n", desc, rc);
524 		rc = PTR_ERR(dev);
525 		goto err;
526 	}
527 
528 	*chardev = dev;
529 
530 	return 0;
531 err:
532 	cdev_del(cdev);
533 	return rc;
534 }
535 
536 int cxl_chardev_d_afu_add(struct cxl_afu *afu)
537 {
538 	return cxl_add_chardev(afu, CXL_AFU_MKDEV_D(afu), &afu->afu_cdev_d,
539 			       &afu->chardev_d, "d", "dedicated",
540 			       &afu_master_fops); /* Uses master fops */
541 }
542 
543 int cxl_chardev_m_afu_add(struct cxl_afu *afu)
544 {
545 	return cxl_add_chardev(afu, CXL_AFU_MKDEV_M(afu), &afu->afu_cdev_m,
546 			       &afu->chardev_m, "m", "master",
547 			       &afu_master_fops);
548 }
549 
550 int cxl_chardev_s_afu_add(struct cxl_afu *afu)
551 {
552 	return cxl_add_chardev(afu, CXL_AFU_MKDEV_S(afu), &afu->afu_cdev_s,
553 			       &afu->chardev_s, "s", "shared",
554 			       &afu_fops);
555 }
556 
557 void cxl_chardev_afu_remove(struct cxl_afu *afu)
558 {
559 	if (afu->chardev_d) {
560 		cdev_del(&afu->afu_cdev_d);
561 		device_unregister(afu->chardev_d);
562 		afu->chardev_d = NULL;
563 	}
564 	if (afu->chardev_m) {
565 		cdev_del(&afu->afu_cdev_m);
566 		device_unregister(afu->chardev_m);
567 		afu->chardev_m = NULL;
568 	}
569 	if (afu->chardev_s) {
570 		cdev_del(&afu->afu_cdev_s);
571 		device_unregister(afu->chardev_s);
572 		afu->chardev_s = NULL;
573 	}
574 }
575 
576 int cxl_register_afu(struct cxl_afu *afu)
577 {
578 	afu->dev.class = cxl_class;
579 
580 	return device_register(&afu->dev);
581 }
582 
583 int cxl_register_adapter(struct cxl *adapter)
584 {
585 	adapter->dev.class = cxl_class;
586 
587 	/*
588 	 * Future: When we support dynamically reprogramming the PSL & AFU we
589 	 * will expose the interface to do that via a chardev:
590 	 * adapter->dev.devt = CXL_CARD_MKDEV(adapter);
591 	 */
592 
593 	return device_register(&adapter->dev);
594 }
595 
596 dev_t cxl_get_dev(void)
597 {
598 	return cxl_dev;
599 }
600 
601 int __init cxl_file_init(void)
602 {
603 	int rc;
604 
605 	/*
606 	 * If these change we really need to update API.  Either change some
607 	 * flags or update API version number CXL_API_VERSION.
608 	 */
609 	BUILD_BUG_ON(CXL_API_VERSION != 3);
610 	BUILD_BUG_ON(sizeof(struct cxl_ioctl_start_work) != 64);
611 	BUILD_BUG_ON(sizeof(struct cxl_event_header) != 8);
612 	BUILD_BUG_ON(sizeof(struct cxl_event_afu_interrupt) != 8);
613 	BUILD_BUG_ON(sizeof(struct cxl_event_data_storage) != 32);
614 	BUILD_BUG_ON(sizeof(struct cxl_event_afu_error) != 16);
615 
616 	if ((rc = alloc_chrdev_region(&cxl_dev, 0, CXL_NUM_MINORS, "cxl"))) {
617 		pr_err("Unable to allocate CXL major number: %i\n", rc);
618 		return rc;
619 	}
620 
621 	pr_devel("CXL device allocated, MAJOR %i\n", MAJOR(cxl_dev));
622 
623 	cxl_class = class_create(THIS_MODULE, "cxl");
624 	if (IS_ERR(cxl_class)) {
625 		pr_err("Unable to create CXL class\n");
626 		rc = PTR_ERR(cxl_class);
627 		goto err;
628 	}
629 	cxl_class->devnode = cxl_devnode;
630 
631 	return 0;
632 
633 err:
634 	unregister_chrdev_region(cxl_dev, CXL_NUM_MINORS);
635 	return rc;
636 }
637 
638 void cxl_file_exit(void)
639 {
640 	unregister_chrdev_region(cxl_dev, CXL_NUM_MINORS);
641 	class_destroy(cxl_class);
642 }
643