summaryrefslogtreecommitdiffstats
path: root/drivers/misc/ocxl/file.c
blob: 038509e5d031f44e99fee275c59b7b08421c9f29 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
// SPDX-License-Identifier: GPL-2.0+
// Copyright 2017 IBM Corp.
#include <linux/fs.h>
#include <linux/poll.h>
#include <linux/sched/signal.h>
#include <linux/uaccess.h>
#include <uapi/misc/ocxl.h>
#include "ocxl_internal.h"


#define OCXL_NUM_MINORS 256 /* Total to reserve */

static dev_t ocxl_dev;
static struct class *ocxl_class;
static struct mutex minors_idr_lock;
static struct idr minors_idr;

static struct ocxl_afu *find_and_get_afu(dev_t devno)
{
	struct ocxl_afu *afu;
	int afu_minor;

	afu_minor = MINOR(devno);
	/*
	 * We don't declare an RCU critical section here, as our AFU
	 * is protected by a reference counter on the device. By the time the
	 * minor number of a device is removed from the idr, the ref count of
	 * the device is already at 0, so no user API will access that AFU and
	 * this function can't return it.
	 */
	afu = idr_find(&minors_idr, afu_minor);
	if (afu)
		ocxl_afu_get(afu);
	return afu;
}

static int allocate_afu_minor(struct ocxl_afu *afu)
{
	int minor;

	mutex_lock(&minors_idr_lock);
	minor = idr_alloc(&minors_idr, afu, 0, OCXL_NUM_MINORS, GFP_KERNEL);
	mutex_unlock(&minors_idr_lock);
	return minor;
}

static void free_afu_minor(struct ocxl_afu *afu)
{
	mutex_lock(&minors_idr_lock);
	idr_remove(&minors_idr, MINOR(afu->dev.devt));
	mutex_unlock(&minors_idr_lock);
}

static int afu_open(struct inode *inode, struct file *file)
{
	struct ocxl_afu *afu;
	struct ocxl_context *ctx;
	int rc;

	pr_debug("%s for device %x\n", __func__, inode->i_rdev);

	afu = find_and_get_afu(inode->i_rdev);
	if (!afu)
		return -ENODEV;

	ctx = ocxl_context_alloc();
	if (!ctx) {
		rc = -ENOMEM;
		goto put_afu;
	}

	rc = ocxl_context_init(ctx, afu, inode->i_mapping);
	if (rc)
		goto put_afu;
	file->private_data = ctx;
	ocxl_afu_put(afu);
	return 0;

put_afu:
	ocxl_afu_put(afu);
	return rc;
}

static long afu_ioctl_attach(struct ocxl_context *ctx,
			struct ocxl_ioctl_attach __user *uarg)
{
	struct ocxl_ioctl_attach arg;
	u64 amr = 0;
	int rc;

	pr_debug("%s for context %d\n", __func__, ctx->pasid);

	if (copy_from_user(&arg, uarg, sizeof(arg)))
		return -EFAULT;

	/* Make sure reserved fields are not set for forward compatibility */
	if (arg.reserved1 || arg.reserved2 || arg.reserved3)
		return -EINVAL;

	amr = arg.amr & mfspr(SPRN_UAMOR);
	rc = ocxl_context_attach(ctx, amr);
	return rc;
}

static long afu_ioctl_get_metadata(struct ocxl_context *ctx,
		struct ocxl_ioctl_metadata __user *uarg)
{
	struct ocxl_ioctl_metadata arg;

	memset(&arg, 0, sizeof(arg));

	arg.version = 0;

	arg.afu_version_major = ctx->afu->config.version_major;
	arg.afu_version_minor = ctx->afu->config.version_minor;
	arg.pasid = ctx->pasid;
	arg.pp_mmio_size = ctx->afu->config.pp_mmio_stride;
	arg.global_mmio_size = ctx->afu->config.global_mmio_size;

	if (copy_to_user(uarg, &arg, sizeof(arg)))
		return -EFAULT;

	return 0;
}

#define CMD_STR(x) (x == OCXL_IOCTL_ATTACH ? "ATTACH" :			\
			x == OCXL_IOCTL_IRQ_ALLOC ? "IRQ_ALLOC" :	\
			x == OCXL_IOCTL_IRQ_FREE ? "IRQ_FREE" :		\
			x == OCXL_IOCTL_IRQ_SET_FD ? "IRQ_SET_FD" :	\
			x == OCXL_IOCTL_GET_METADATA ? "GET_METADATA" :	\
			"UNKNOWN")

static long afu_ioctl(struct file *file, unsigned int cmd,
		unsigned long args)
{
	struct ocxl_context *ctx = file->private_data;
	struct ocxl_ioctl_irq_fd irq_fd;
	u64 irq_offset;
	long rc;

	pr_debug("%s for context %d, command %s\n", __func__, ctx->pasid,
		CMD_STR(cmd));

	if (ctx->status == CLOSED)
		return -EIO;

	switch (cmd) {
	case OCXL_IOCTL_ATTACH:
		rc = afu_ioctl_attach(ctx,
				(struct ocxl_ioctl_attach __user *) args);
		break;

	case OCXL_IOCTL_IRQ_ALLOC:
		rc = ocxl_afu_irq_alloc(ctx, &irq_offset);
		if (!rc) {
			rc = copy_to_user((u64 __user *) args, &irq_offset,
					sizeof(irq_offset));
			if (rc) {
				ocxl_afu_irq_free(ctx, irq_offset);
				return -EFAULT;
			}
		}
		break;

	case OCXL_IOCTL_IRQ_FREE:
		rc = copy_from_user(&irq_offset, (u64 __user *) args,
				sizeof(irq_offset));
		if (rc)
			return -EFAULT;
		rc = ocxl_afu_irq_free(ctx, irq_offset);
		break;

	case OCXL_IOCTL_IRQ_SET_FD:
		rc = copy_from_user(&irq_fd, (u64 __user *) args,
				sizeof(irq_fd));
		if (rc)
			return -EFAULT;
		if (irq_fd.reserved)
			return -EINVAL;
		rc = ocxl_afu_irq_set_fd(ctx, irq_fd.irq_offset,
					irq_fd.eventfd);
		break;

	case OCXL_IOCTL_GET_METADATA:
		rc = afu_ioctl_get_metadata(ctx,
				(struct ocxl_ioctl_metadata __user *) args);
		break;

	default:
		rc = -EINVAL;
	}
	return rc;
}

static long afu_compat_ioctl(struct file *file, unsigned int cmd,
			unsigned long args)
{
	return afu_ioctl(file, cmd, args);
}

static int afu_mmap(struct file *file, struct vm_area_struct *vma)
{
	struct ocxl_context *ctx = file->private_data;

	pr_debug("%s for context %d\n", __func__, ctx->pasid);
	return ocxl_context_mmap(ctx, vma);
}

static bool has_xsl_error(struct ocxl_context *ctx)
{
	bool ret;

	mutex_lock(&ctx->xsl_error_lock);
	ret = !!ctx->xsl_error.addr;
	mutex_unlock(&ctx->xsl_error_lock);

	return ret;
}

/*
 * Are there any events pending on the AFU
 * ctx: The AFU context
 * Returns: true if there are events pending
 */
static bool afu_events_pending(struct ocxl_context *ctx)
{
	if (has_xsl_error(ctx))
		return true;
	return false;
}

static unsigned int afu_poll(struct file *file, struct poll_table_struct *wait)
{
	struct ocxl_context *ctx = file->private_data;
	unsigned int mask = 0;
	bool closed;

	pr_debug("%s for context %d\n", __func__, ctx->pasid);

	poll_wait(file, &ctx->events_wq, wait);

	mutex_lock(&ctx->status_mutex);
	closed = (ctx->status == CLOSED);
	mutex_unlock(&ctx->status_mutex);

	if (afu_events_pending(ctx))
		mask = EPOLLIN | EPOLLRDNORM;
	else if (closed)
		mask = EPOLLERR;

	return mask;
}

/*
 * Populate the supplied buffer with a single XSL error
 * ctx:	The AFU context to report the error from
 * header: the event header to populate
 * buf: The buffer to write the body into (should be at least
 *      AFU_EVENT_BODY_XSL_ERROR_SIZE)
 * Return: the amount of buffer that was populated
 */
static ssize_t append_xsl_error(struct ocxl_context *ctx,
				struct ocxl_kernel_event_header *header,
				char __user *buf)
{
	struct ocxl_kernel_event_xsl_fault_error body;

	memset(&body, 0, sizeof(body));

	mutex_lock(&ctx->xsl_error_lock);
	if (!ctx->xsl_error.addr) {
		mutex_unlock(&ctx->xsl_error_lock);
		return 0;
	}

	body.addr = ctx->xsl_error.addr;
	body.dsisr = ctx->xsl_error.dsisr;
	body.count = ctx->xsl_error.count;

	ctx->xsl_error.addr = 0;
	ctx->xsl_error.dsisr = 0;
	ctx->xsl_error.count = 0;

	mutex_unlock(&ctx->xsl_error_lock);

	header->type = OCXL_AFU_EVENT_XSL_FAULT_ERROR;

	if (copy_to_user(buf, &body, sizeof(body)))
		return -EFAULT;

	return sizeof(body);
}

#define AFU_EVENT_BODY_MAX_SIZE sizeof(struct ocxl_kernel_event_xsl_fault_error)

/*
 * Reports events on the AFU
 * Format:
 *	Header (struct ocxl_kernel_event_header)
 *	Body (struct ocxl_kernel_event_*)
 *	Header...
 */
static ssize_t afu_read(struct file *file, char __user *buf, size_t count,
			loff_t *off)
{
	struct ocxl_context *ctx = file->private_data;
	struct ocxl_kernel_event_header header;
	ssize_t rc;
	ssize_t used = 0;
	DEFINE_WAIT(event_wait);

	memset(&header, 0, sizeof(header));

	/* Require offset to be 0 */
	if (*off != 0)
		return -EINVAL;

	if (count < (sizeof(struct ocxl_kernel_event_header) +
			AFU_EVENT_BODY_MAX_SIZE))
		return -EINVAL;

	for (;;) {
		prepare_to_wait(&ctx->events_wq, &event_wait,
				TASK_INTERRUPTIBLE);

		if (afu_events_pending(ctx))
			break;

		if (ctx->status == CLOSED)
			break;

		if (file->f_flags & O_NONBLOCK) {
			finish_wait(&ctx->events_wq, &event_wait);
			return -EAGAIN;
		}

		if (signal_pending(current)) {
			finish_wait(&ctx->events_wq, &event_wait);
			return -ERESTARTSYS;
		}

		schedule();
	}

	finish_wait(&ctx->events_wq, &event_wait);

	if (has_xsl_error(ctx)) {
		used = append_xsl_error(ctx, &header, buf + sizeof(header));
		if (used < 0)
			return used;
	}

	if (!afu_events_pending(ctx))
		header.flags |= OCXL_KERNEL_EVENT_FLAG_LAST;

	if (copy_to_user(buf, &header, sizeof(header)))
		return -EFAULT;

	used += sizeof(header);

	rc = used;
	return rc;
}

static int afu_release(struct inode *inode, struct file *file)
{
	struct ocxl_context *ctx = file->private_data;
	int rc;

	pr_debug("%s for device %x\n", __func__, inode->i_rdev);
	rc = ocxl_context_detach(ctx);
	mutex_lock(&ctx->mapping_lock);
	ctx->mapping = NULL;
	mutex_unlock(&ctx->mapping_lock);
	wake_up_all(&ctx->events_wq);
	if (rc != -EBUSY)
		ocxl_context_free(ctx);
	return 0;
}

static const struct file_operations ocxl_afu_fops = {
	.owner		= THIS_MODULE,
	.open           = afu_open,
	.unlocked_ioctl = afu_ioctl,
	.compat_ioctl   = afu_compat_ioctl,
	.mmap           = afu_mmap,
	.poll           = afu_poll,
	.read           = afu_read,
	.release        = afu_release,
};

int ocxl_create_cdev(struct ocxl_afu *afu)
{
	int rc;

	cdev_init(&afu->cdev, &ocxl_afu_fops);
	rc = cdev_add(&afu->cdev, afu->dev.devt, 1);
	if (rc) {
		dev_err(&afu->dev, "Unable to add afu char device: %d\n", rc);
		return rc;
	}
	return 0;
}

void ocxl_destroy_cdev(struct ocxl_afu *afu)
{
	cdev_del(&afu->cdev);
}

int ocxl_register_afu(struct ocxl_afu *afu)
{
	int minor;

	minor = allocate_afu_minor(afu);
	if (minor < 0)
		return minor;
	afu->dev.devt = MKDEV(MAJOR(ocxl_dev), minor);
	afu->dev.class = ocxl_class;
	return device_register(&afu->dev);
}

void ocxl_unregister_afu(struct ocxl_afu *afu)
{
	free_afu_minor(afu);
}

static char *ocxl_devnode(struct device *dev, umode_t *mode)
{
	return kasprintf(GFP_KERNEL, "ocxl/%s", dev_name(dev));
}

int ocxl_file_init(void)
{
	int rc;

	mutex_init(&minors_idr_lock);
	idr_init(&minors_idr);

	rc = alloc_chrdev_region(&ocxl_dev, 0, OCXL_NUM_MINORS, "ocxl");
	if (rc) {
		pr_err("Unable to allocate ocxl major number: %d\n", rc);
		return rc;
	}

	ocxl_class = class_create(THIS_MODULE, "ocxl");
	if (IS_ERR(ocxl_class)) {
		pr_err("Unable to create ocxl class\n");
		unregister_chrdev_region(ocxl_dev, OCXL_NUM_MINORS);
		return PTR_ERR(ocxl_class);
	}

	ocxl_class->devnode = ocxl_devnode;
	return 0;
}

void ocxl_file_exit(void)
{
	class_destroy(ocxl_class);
	unregister_chrdev_region(ocxl_dev, OCXL_NUM_MINORS);
	idr_destroy(&minors_idr);
}
OpenPOWER on IntegriCloud