summaryrefslogtreecommitdiffstats
path: root/drivers/s390/char/sclp_sd.c
blob: f9e164be7568f2c877609d1a487ab1d2ff6279b6 (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
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
// SPDX-License-Identifier: GPL-2.0
/*
 * SCLP Store Data support and sysfs interface
 *
 * Copyright IBM Corp. 2017
 */

#define KMSG_COMPONENT "sclp_sd"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt

#include <linux/completion.h>
#include <linux/kobject.h>
#include <linux/list.h>
#include <linux/printk.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/async.h>
#include <linux/export.h>
#include <linux/mutex.h>

#include <asm/pgalloc.h>

#include "sclp.h"

#define SD_EQ_STORE_DATA	0
#define SD_EQ_HALT		1
#define SD_EQ_SIZE		2

#define SD_DI_CONFIG		3

struct sclp_sd_evbuf {
	struct evbuf_header hdr;
	u8 eq;
	u8 di;
	u8 rflags;
	u64 :56;
	u32 id;
	u16 :16;
	u8 fmt;
	u8 status;
	u64 sat;
	u64 sa;
	u32 esize;
	u32 dsize;
} __packed;

struct sclp_sd_sccb {
	struct sccb_header hdr;
	struct sclp_sd_evbuf evbuf;
} __packed __aligned(PAGE_SIZE);

/**
 * struct sclp_sd_data - Result of a Store Data request
 * @esize_bytes: Resulting esize in bytes
 * @dsize_bytes: Resulting dsize in bytes
 * @data: Pointer to data - must be released using vfree()
 */
struct sclp_sd_data {
	size_t esize_bytes;
	size_t dsize_bytes;
	void *data;
};

/**
 * struct sclp_sd_listener - Listener for asynchronous Store Data response
 * @list: For enqueueing this struct
 * @id: Event ID of response to listen for
 * @completion: Can be used to wait for response
 * @evbuf: Contains the resulting Store Data response after completion
 */
struct sclp_sd_listener {
	struct list_head list;
	u32 id;
	struct completion completion;
	struct sclp_sd_evbuf evbuf;
};

/**
 * struct sclp_sd_file - Sysfs representation of a Store Data entity
 * @kobj: Kobject
 * @data_attr: Attribute for accessing data contents
 * @data_mutex: Mutex to serialize access and updates to @data
 * @data: Data associated with this entity
 * @di: DI value associated with this entity
 */
struct sclp_sd_file {
	struct kobject kobj;
	struct bin_attribute data_attr;
	struct mutex data_mutex;
	struct sclp_sd_data data;
	u8 di;
};
#define to_sd_file(x) container_of(x, struct sclp_sd_file, kobj)

static struct kset *sclp_sd_kset;
static struct sclp_sd_file *config_file;

static LIST_HEAD(sclp_sd_queue);
static DEFINE_SPINLOCK(sclp_sd_queue_lock);

/**
 * sclp_sd_listener_add() - Add listener for Store Data responses
 * @listener: Listener to add
 */
static void sclp_sd_listener_add(struct sclp_sd_listener *listener)
{
	spin_lock_irq(&sclp_sd_queue_lock);
	list_add_tail(&listener->list, &sclp_sd_queue);
	spin_unlock_irq(&sclp_sd_queue_lock);
}

/**
 * sclp_sd_listener_remove() - Remove listener for Store Data responses
 * @listener: Listener to remove
 */
static void sclp_sd_listener_remove(struct sclp_sd_listener *listener)
{
	spin_lock_irq(&sclp_sd_queue_lock);
	list_del(&listener->list);
	spin_unlock_irq(&sclp_sd_queue_lock);
}

/**
 * sclp_sd_listener_init() - Initialize a Store Data response listener
 * @listener: Response listener to initialize
 * @id: Event ID to listen for
 *
 * Initialize a listener for asynchronous Store Data responses. This listener
 * can afterwards be used to wait for a specific response and to retrieve
 * the associated response data.
 */
static void sclp_sd_listener_init(struct sclp_sd_listener *listener, u32 id)
{
	memset(listener, 0, sizeof(*listener));
	listener->id = id;
	init_completion(&listener->completion);
}

/**
 * sclp_sd_receiver() - Receiver for Store Data events
 * @evbuf_hdr: Header of received events
 *
 * Process Store Data events and complete listeners with matching event IDs.
 */
static void sclp_sd_receiver(struct evbuf_header *evbuf_hdr)
{
	struct sclp_sd_evbuf *evbuf = (struct sclp_sd_evbuf *) evbuf_hdr;
	struct sclp_sd_listener *listener;
	int found = 0;

	pr_debug("received event (id=0x%08x)\n", evbuf->id);
	spin_lock(&sclp_sd_queue_lock);
	list_for_each_entry(listener, &sclp_sd_queue, list) {
		if (listener->id != evbuf->id)
			continue;

		listener->evbuf = *evbuf;
		complete(&listener->completion);
		found = 1;
		break;
	}
	spin_unlock(&sclp_sd_queue_lock);

	if (!found)
		pr_debug("unsolicited event (id=0x%08x)\n", evbuf->id);
}

static struct sclp_register sclp_sd_register = {
	.send_mask = EVTYP_STORE_DATA_MASK,
	.receive_mask = EVTYP_STORE_DATA_MASK,
	.receiver_fn = sclp_sd_receiver,
};

/**
 * sclp_sd_sync() - Perform Store Data request synchronously
 * @page: Address of work page - must be below 2GB
 * @eq: Input EQ value
 * @di: Input DI value
 * @sat: Input SAT value
 * @sa: Input SA value used to specify the address of the target buffer
 * @dsize_ptr: Optional pointer to input and output DSIZE value
 * @esize_ptr: Optional pointer to output ESIZE value
 *
 * Perform Store Data request with specified parameters and wait for completion.
 *
 * Return %0 on success and store resulting DSIZE and ESIZE values in
 * @dsize_ptr and @esize_ptr (if provided). Return non-zero on error.
 */
static int sclp_sd_sync(unsigned long page, u8 eq, u8 di, u64 sat, u64 sa,
			u32 *dsize_ptr, u32 *esize_ptr)
{
	struct sclp_sd_sccb *sccb = (void *) page;
	struct sclp_sd_listener listener;
	struct sclp_sd_evbuf *evbuf;
	int rc;

	sclp_sd_listener_init(&listener, __pa(sccb));
	sclp_sd_listener_add(&listener);

	/* Prepare SCCB */
	memset(sccb, 0, PAGE_SIZE);
	sccb->hdr.length = sizeof(sccb->hdr) + sizeof(sccb->evbuf);
	evbuf = &sccb->evbuf;
	evbuf->hdr.length = sizeof(*evbuf);
	evbuf->hdr.type = EVTYP_STORE_DATA;
	evbuf->eq = eq;
	evbuf->di = di;
	evbuf->id = listener.id;
	evbuf->fmt = 1;
	evbuf->sat = sat;
	evbuf->sa = sa;
	if (dsize_ptr)
		evbuf->dsize = *dsize_ptr;

	/* Perform command */
	pr_debug("request (eq=%d, di=%d, id=0x%08x)\n", eq, di, listener.id);
	rc = sclp_sync_request(SCLP_CMDW_WRITE_EVENT_DATA, sccb);
	pr_debug("request done (rc=%d)\n", rc);
	if (rc)
		goto out;

	/* Evaluate response */
	if (sccb->hdr.response_code == 0x73f0) {
		pr_debug("event not supported\n");
		rc = -EIO;
		goto out_remove;
	}
	if (sccb->hdr.response_code != 0x0020 || !(evbuf->hdr.flags & 0x80)) {
		rc = -EIO;
		goto out;
	}
	if (!(evbuf->rflags & 0x80)) {
		rc = wait_for_completion_interruptible(&listener.completion);
		if (rc)
			goto out;
		evbuf = &listener.evbuf;
	}
	switch (evbuf->status) {
	case 0:
		if (dsize_ptr)
			*dsize_ptr = evbuf->dsize;
		if (esize_ptr)
			*esize_ptr = evbuf->esize;
		pr_debug("success (dsize=%u, esize=%u)\n", evbuf->dsize,
			 evbuf->esize);
		break;
	case 3:
		rc = -ENOENT;
		break;
	default:
		rc = -EIO;
		break;

	}

out:
	if (rc && rc != -ENOENT) {
		/* Provide some information about what went wrong */
		pr_warn("Store Data request failed (eq=%d, di=%d, "
			"response=0x%04x, flags=0x%02x, status=%d, rc=%d)\n",
			eq, di, sccb->hdr.response_code, evbuf->hdr.flags,
			evbuf->status, rc);
	}

out_remove:
	sclp_sd_listener_remove(&listener);

	return rc;
}

/**
 * sclp_sd_store_data() - Obtain data for specified Store Data entity
 * @result: Resulting data
 * @di: DI value associated with this entity
 *
 * Perform a series of Store Data requests to obtain the size and contents of
 * the specified Store Data entity.
 *
 * Return:
 *   %0:       Success - result is stored in @result. @result->data must be
 *	       released using vfree() after use.
 *   %-ENOENT: No data available for this entity
 *   %<0:      Other error
 */
static int sclp_sd_store_data(struct sclp_sd_data *result, u8 di)
{
	u32 dsize = 0, esize = 0;
	unsigned long page, asce = 0;
	void *data = NULL;
	int rc;

	page = __get_free_page(GFP_KERNEL | GFP_DMA);
	if (!page)
		return -ENOMEM;

	/* Get size */
	rc = sclp_sd_sync(page, SD_EQ_SIZE, di, 0, 0, &dsize, &esize);
	if (rc)
		goto out;
	if (dsize == 0)
		goto out_result;

	/* Allocate memory */
	data = vzalloc(array_size((size_t)dsize, PAGE_SIZE));
	if (!data) {
		rc = -ENOMEM;
		goto out;
	}

	/* Get translation table for buffer */
	asce = base_asce_alloc((unsigned long) data, dsize);
	if (!asce) {
		vfree(data);
		rc = -ENOMEM;
		goto out;
	}

	/* Get data */
	rc = sclp_sd_sync(page, SD_EQ_STORE_DATA, di, asce, (u64) data, &dsize,
			  &esize);
	if (rc) {
		/* Cancel running request if interrupted */
		if (rc == -ERESTARTSYS)
			sclp_sd_sync(page, SD_EQ_HALT, di, 0, 0, NULL, NULL);
		vfree(data);
		goto out;
	}

out_result:
	result->esize_bytes = (size_t) esize * PAGE_SIZE;
	result->dsize_bytes = (size_t) dsize * PAGE_SIZE;
	result->data = data;

out:
	base_asce_free(asce);
	free_page(page);

	return rc;
}

/**
 * sclp_sd_data_reset() - Reset Store Data result buffer
 * @data: Data buffer to reset
 *
 * Reset @data to initial state and release associated memory.
 */
static void sclp_sd_data_reset(struct sclp_sd_data *data)
{
	vfree(data->data);
	data->data = NULL;
	data->dsize_bytes = 0;
	data->esize_bytes = 0;
}

/**
 * sclp_sd_file_release() - Release function for sclp_sd_file object
 * @kobj: Kobject embedded in sclp_sd_file object
 */
static void sclp_sd_file_release(struct kobject *kobj)
{
	struct sclp_sd_file *sd_file = to_sd_file(kobj);

	sclp_sd_data_reset(&sd_file->data);
	kfree(sd_file);
}

/**
 * sclp_sd_file_update() - Update contents of sclp_sd_file object
 * @sd_file: Object to update
 *
 * Obtain the current version of data associated with the Store Data entity
 * @sd_file.
 *
 * On success, return %0 and generate a KOBJ_CHANGE event to indicate that the
 * data may have changed. Return non-zero otherwise.
 */
static int sclp_sd_file_update(struct sclp_sd_file *sd_file)
{
	const char *name = kobject_name(&sd_file->kobj);
	struct sclp_sd_data data;
	int rc;

	rc = sclp_sd_store_data(&data, sd_file->di);
	if (rc) {
		if (rc == -ENOENT) {
			pr_info("No data is available for the %s data entity\n",
				 name);
		}
		return rc;
	}

	mutex_lock(&sd_file->data_mutex);
	sclp_sd_data_reset(&sd_file->data);
	sd_file->data = data;
	mutex_unlock(&sd_file->data_mutex);

	pr_info("A %zu-byte %s data entity was retrieved\n", data.dsize_bytes,
		name);
	kobject_uevent(&sd_file->kobj, KOBJ_CHANGE);

	return 0;
}

/**
 * sclp_sd_file_update_async() - Wrapper for asynchronous update call
 * @data: Object to update
 * @cookie: Unused
 */
static void sclp_sd_file_update_async(void *data, async_cookie_t cookie)
{
	struct sclp_sd_file *sd_file = data;

	sclp_sd_file_update(sd_file);
}

/**
 * reload_store() - Store function for "reload" sysfs attribute
 * @kobj: Kobject of sclp_sd_file object
 * @attr: Reload attribute
 * @buf: Data written to sysfs attribute
 * @count: Count of bytes written
 *
 * Initiate a reload of the data associated with an sclp_sd_file object.
 */
static ssize_t reload_store(struct kobject *kobj, struct kobj_attribute *attr,
			    const char *buf, size_t count)
{
	struct sclp_sd_file *sd_file = to_sd_file(kobj);

	sclp_sd_file_update(sd_file);

	return count;
}

static struct kobj_attribute reload_attr = __ATTR_WO(reload);

static struct attribute *sclp_sd_file_default_attrs[] = {
	&reload_attr.attr,
	NULL,
};
ATTRIBUTE_GROUPS(sclp_sd_file_default);

static struct kobj_type sclp_sd_file_ktype = {
	.sysfs_ops = &kobj_sysfs_ops,
	.release = sclp_sd_file_release,
	.default_groups = sclp_sd_file_default_groups,
};

/**
 * data_read() - Read function for "data" sysfs attribute
 * @file: Open file pointer
 * @kobj: Kobject of sclp_sd_file object
 * @attr: Data attribute
 * @buffer: Target buffer
 * @off: Requested file offset
 * @size: Requested number of bytes
 *
 * Store the requested portion of the Store Data entity contents into the
 * specified buffer. Return the number of bytes stored on success, or %0
 * on EOF.
 */
static ssize_t data_read(struct file *file, struct kobject *kobj,
			 struct bin_attribute *attr, char *buffer,
			 loff_t off, size_t size)
{
	struct sclp_sd_file *sd_file = to_sd_file(kobj);
	size_t data_size;
	char *data;

	mutex_lock(&sd_file->data_mutex);

	data = sd_file->data.data;
	data_size = sd_file->data.dsize_bytes;
	if (!data || off >= data_size) {
		size = 0;
	} else {
		if (off + size > data_size)
			size = data_size - off;
		memcpy(buffer, data + off, size);
	}

	mutex_unlock(&sd_file->data_mutex);

	return size;
}

/**
 * sclp_sd_file_create() - Add a sysfs file representing a Store Data entity
 * @name: Name of file
 * @di: DI value associated with this entity
 *
 * Create a sysfs directory with the given @name located under
 *
 *   /sys/firmware/sclp_sd/
 *
 * The files in this directory can be used to access the contents of the Store
 * Data entity associated with @DI.
 *
 * Return pointer to resulting sclp_sd_file object on success, %NULL otherwise.
 * The object must be freed by calling kobject_put() on the embedded kobject
 * pointer after use.
 */
static __init struct sclp_sd_file *sclp_sd_file_create(const char *name, u8 di)
{
	struct sclp_sd_file *sd_file;
	int rc;

	sd_file = kzalloc(sizeof(*sd_file), GFP_KERNEL);
	if (!sd_file)
		return NULL;
	sd_file->di = di;
	mutex_init(&sd_file->data_mutex);

	/* Create kobject located under /sys/firmware/sclp_sd/ */
	sd_file->kobj.kset = sclp_sd_kset;
	rc = kobject_init_and_add(&sd_file->kobj, &sclp_sd_file_ktype, NULL,
				  "%s", name);
	if (rc) {
		kobject_put(&sd_file->kobj);
		return NULL;
	}

	sysfs_bin_attr_init(&sd_file->data_attr);
	sd_file->data_attr.attr.name = "data";
	sd_file->data_attr.attr.mode = 0444;
	sd_file->data_attr.read = data_read;

	rc = sysfs_create_bin_file(&sd_file->kobj, &sd_file->data_attr);
	if (rc) {
		kobject_put(&sd_file->kobj);
		return NULL;
	}

	/*
	 * For completeness only - users interested in entity data should listen
	 * for KOBJ_CHANGE instead.
	 */
	kobject_uevent(&sd_file->kobj, KOBJ_ADD);

	/* Don't let a slow Store Data request delay further initialization */
	async_schedule(sclp_sd_file_update_async, sd_file);

	return sd_file;
}

/**
 * sclp_sd_init() - Initialize sclp_sd support and register sysfs files
 */
static __init int sclp_sd_init(void)
{
	int rc;

	rc = sclp_register(&sclp_sd_register);
	if (rc)
		return rc;

	/* Create kset named "sclp_sd" located under /sys/firmware/ */
	rc = -ENOMEM;
	sclp_sd_kset = kset_create_and_add("sclp_sd", NULL, firmware_kobj);
	if (!sclp_sd_kset)
		goto err_kset;

	rc = -EINVAL;
	config_file = sclp_sd_file_create("config", SD_DI_CONFIG);
	if (!config_file)
		goto err_config;

	return 0;

err_config:
	kset_unregister(sclp_sd_kset);
err_kset:
	sclp_unregister(&sclp_sd_register);

	return rc;
}
device_initcall(sclp_sd_init);