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
16static dev_t ocxl_dev;
17static DEFINE_MUTEX(minors_idr_lock);
18static struct idr minors_idr;
19
20static 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
32static 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
42static 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
49static 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
71static 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
90static 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
112static 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
156static 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
183static 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
191static void irq_free(void *private)
192{
193	struct eventfd_ctx *ev_ctx = private;
194
195	eventfd_ctx_put(ev_ctx);
196}
197
198static 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
286static long afu_compat_ioctl(struct file *file, unsigned int cmd,
287			unsigned long args)
288{
289	return afu_ioctl(file, cmd, args);
290}
291
292static 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
300static 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 */
316static bool afu_events_pending(struct ocxl_context *ctx)
317{
318	if (has_xsl_error(ctx))
319		return true;
320	return false;
321}
322
323static 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 */
353static 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 */
394static 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
456static 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
472static 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
484static 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
492static 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
506static void ocxl_file_make_invisible(struct ocxl_file_info *info)
507{
508	cdev_del(&info->cdev);
509}
510
511static char *ocxl_devnode(const struct device *dev, umode_t *mode)
512{
513	return kasprintf(GFP_KERNEL, "ocxl/%s", dev_name(dev));
514}
515
516static const struct class ocxl_class = {
517	.name =		"ocxl",
518	.devnode =	ocxl_devnode,
519};
520
521int 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
571err_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;
576err_put:
577	ocxl_afu_put(afu);
578	free_minor(info);
579	kfree(info);
580	return rc;
581}
582
583void 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
596int 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
618void 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