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