aboutsummaryrefslogtreecommitdiff
path: root/drivers/s390/char/vmlogrdr.c
blob: 58333cb4503f4db1e3c76aa188e820997b2d9b6b (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
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
// SPDX-License-Identifier: GPL-2.0
/*
 *	character device driver for reading z/VM system service records
 *
 *
 *	Copyright IBM Corp. 2004, 2009
 *	character device driver for reading z/VM system service records,
 *	Version 1.0
 *	Author(s): Xenia Tkatschow <xenia@us.ibm.com>
 *		   Stefan Weinhuber <wein@de.ibm.com>
 *
 */

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

#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/atomic.h>
#include <linux/uaccess.h>
#include <asm/cpcmd.h>
#include <asm/debug.h>
#include <asm/ebcdic.h>
#include <net/iucv/iucv.h>
#include <linux/kmod.h>
#include <linux/cdev.h>
#include <linux/device.h>
#include <linux/string.h>

MODULE_AUTHOR
	("(C) 2004 IBM Corporation by Xenia Tkatschow (xenia@us.ibm.com)\n"
	 "                            Stefan Weinhuber (wein@de.ibm.com)");
MODULE_DESCRIPTION ("Character device driver for reading z/VM "
		    "system service records.");
MODULE_LICENSE("GPL");


/*
 * The size of the buffer for iucv data transfer is one page,
 * but in addition to the data we read from iucv we also
 * place an integer and some characters into that buffer,
 * so the maximum size for record data is a little less then
 * one page.
 */
#define NET_BUFFER_SIZE	(PAGE_SIZE - sizeof(int) - sizeof(FENCE))

/*
 * The elements that are concurrently accessed by bottom halves are
 * connection_established, iucv_path_severed, local_interrupt_buffer
 * and receive_ready. The first three can be protected by
 * priv_lock.  receive_ready is atomic, so it can be incremented and
 * decremented without holding a lock.
 * The variable dev_in_use needs to be protected by the lock, since
 * it's a flag used by open to make sure that the device is opened only
 * by one user at the same time.
 */
struct vmlogrdr_priv_t {
	char system_service[8];
	char internal_name[8];
	char recording_name[8];
	struct iucv_path *path;
	int connection_established;
	int iucv_path_severed;
	struct iucv_message local_interrupt_buffer;
	atomic_t receive_ready;
	int minor_num;
	char * buffer;
	char * current_position;
	int remaining;
	ulong residual_length;
	int buffer_free;
	int dev_in_use; /* 1: already opened, 0: not opened*/
	spinlock_t priv_lock;
	struct device  *device;
	struct device  *class_device;
	int autorecording;
	int autopurge;
};


/*
 * File operation structure for vmlogrdr devices
 */
static int vmlogrdr_open(struct inode *, struct file *);
static int vmlogrdr_release(struct inode *, struct file *);
static ssize_t vmlogrdr_read (struct file *filp, char __user *data,
			      size_t count, loff_t * ppos);

static const struct file_operations vmlogrdr_fops = {
	.owner   = THIS_MODULE,
	.open    = vmlogrdr_open,
	.release = vmlogrdr_release,
	.read    = vmlogrdr_read,
	.llseek  = no_llseek,
};


static void vmlogrdr_iucv_path_complete(struct iucv_path *, u8 *ipuser);
static void vmlogrdr_iucv_path_severed(struct iucv_path *, u8 *ipuser);
static void vmlogrdr_iucv_message_pending(struct iucv_path *,
					  struct iucv_message *);


static struct iucv_handler vmlogrdr_iucv_handler = {
	.path_complete	 = vmlogrdr_iucv_path_complete,
	.path_severed	 = vmlogrdr_iucv_path_severed,
	.message_pending = vmlogrdr_iucv_message_pending,
};


static DECLARE_WAIT_QUEUE_HEAD(conn_wait_queue);
static DECLARE_WAIT_QUEUE_HEAD(read_wait_queue);

/*
 * pointer to system service private structure
 * minor number 0 --> logrec
 * minor number 1 --> account
 * minor number 2 --> symptom
 */

static struct vmlogrdr_priv_t sys_ser[] = {
	{ .system_service = "*LOGREC ",
	  .internal_name  = "logrec",
	  .recording_name = "EREP",
	  .minor_num      = 0,
	  .buffer_free    = 1,
	  .priv_lock	  = __SPIN_LOCK_UNLOCKED(sys_ser[0].priv_lock),
	  .autorecording  = 1,
	  .autopurge      = 1,
	},
	{ .system_service = "*ACCOUNT",
	  .internal_name  = "account",
	  .recording_name = "ACCOUNT",
	  .minor_num      = 1,
	  .buffer_free    = 1,
	  .priv_lock	  = __SPIN_LOCK_UNLOCKED(sys_ser[1].priv_lock),
	  .autorecording  = 1,
	  .autopurge      = 1,
	},
	{ .system_service = "*SYMPTOM",
	  .internal_name  = "symptom",
	  .recording_name = "SYMPTOM",
	  .minor_num      = 2,
	  .buffer_free    = 1,
	  .priv_lock	  = __SPIN_LOCK_UNLOCKED(sys_ser[2].priv_lock),
	  .autorecording  = 1,
	  .autopurge      = 1,
	}
};

#define MAXMINOR  ARRAY_SIZE(sys_ser)

static char FENCE[] = {"EOR"};
static int vmlogrdr_major = 0;
static struct cdev  *vmlogrdr_cdev = NULL;
static int recording_class_AB;


static void vmlogrdr_iucv_path_complete(struct iucv_path *path, u8 *ipuser)
{
	struct vmlogrdr_priv_t * logptr = path->private;

	spin_lock(&logptr->priv_lock);
	logptr->connection_established = 1;
	spin_unlock(&logptr->priv_lock);
	wake_up(&conn_wait_queue);
}


static void vmlogrdr_iucv_path_severed(struct iucv_path *path, u8 *ipuser)
{
	struct vmlogrdr_priv_t * logptr = path->private;
	u8 reason = (u8) ipuser[8];

	pr_err("vmlogrdr: connection severed with reason %i\n", reason);

	iucv_path_sever(path, NULL);
	kfree(path);
	logptr->path = NULL;

	spin_lock(&logptr->priv_lock);
	logptr->connection_established = 0;
	logptr->iucv_path_severed = 1;
	spin_unlock(&logptr->priv_lock);

	wake_up(&conn_wait_queue);
	/* just in case we're sleeping waiting for a record */
	wake_up_interruptible(&read_wait_queue);
}


static void vmlogrdr_iucv_message_pending(struct iucv_path *path,
					  struct iucv_message *msg)
{
	struct vmlogrdr_priv_t * logptr = path->private;

	/*
	 * This function is the bottom half so it should be quick.
	 * Copy the external interrupt data into our local eib and increment
	 * the usage count
	 */
	spin_lock(&logptr->priv_lock);
	memcpy(&logptr->local_interrupt_buffer, msg, sizeof(*msg));
	atomic_inc(&logptr->receive_ready);
	spin_unlock(&logptr->priv_lock);
	wake_up_interruptible(&read_wait_queue);
}


static int vmlogrdr_get_recording_class_AB(void)
{
	static const char cp_command[] = "QUERY COMMAND RECORDING ";
	char cp_response[80];
	char *tail;
	int len,i;

	cpcmd(cp_command, cp_response, sizeof(cp_response), NULL);
	len = strnlen(cp_response,sizeof(cp_response));
	// now the parsing
	tail=strnchr(cp_response,len,'=');
	if (!tail)
		return 0;
	tail++;
	if (!strncmp("ANY",tail,3))
		return 1;
	if (!strncmp("NONE",tail,4))
		return 0;
	/*
	 * expect comma separated list of classes here, if one of them
	 * is A or B return 1 otherwise 0
	 */
        for (i=tail-cp_response; i<len; i++)
		if ( cp_response[i]=='A' || cp_response[i]=='B' )
			return 1;
	return 0;
}


static int vmlogrdr_recording(struct vmlogrdr_priv_t * logptr,
			      int action, int purge)
{

	char cp_command[80];
	char cp_response[160];
	char *onoff, *qid_string;
	int rc;

	onoff = ((action == 1) ? "ON" : "OFF");
	qid_string = ((recording_class_AB == 1) ? " QID * " : "");

	/*
	 * The recording commands needs to be called with option QID
	 * for guests that have previlege classes A or B.
	 * Purging has to be done as separate step, because recording
	 * can't be switched on as long as records are on the queue.
	 * Doing both at the same time doesn't work.
	 */
	if (purge && (action == 1)) {
		memset(cp_command, 0x00, sizeof(cp_command));
		memset(cp_response, 0x00, sizeof(cp_response));
		snprintf(cp_command, sizeof(cp_command),
			 "RECORDING %s PURGE %s",
			 logptr->recording_name,
			 qid_string);
		cpcmd(cp_command, cp_response, sizeof(cp_response), NULL);
	}

	memset(cp_command, 0x00, sizeof(cp_command));
	memset(cp_response, 0x00, sizeof(cp_response));
	snprintf(cp_command, sizeof(cp_command), "RECORDING %s %s %s",
		logptr->recording_name,
		onoff,
		qid_string);
	cpcmd(cp_command, cp_response, sizeof(cp_response), NULL);
	/* The recording command will usually answer with 'Command complete'
	 * on success, but when the specific service was never connected
	 * before then there might be an additional informational message
	 * 'HCPCRC8072I Recording entry not found' before the
	 * 'Command complete'. So I use strstr rather then the strncmp.
	 */
	if (strstr(cp_response,"Command complete"))
		rc = 0;
	else
		rc = -EIO;
	/*
	 * If we turn recording off, we have to purge any remaining records
	 * afterwards, as a large number of queued records may impact z/VM
	 * performance.
	 */
	if (purge && (action == 0)) {
		memset(cp_command, 0x00, sizeof(cp_command));
		memset(cp_response, 0x00, sizeof(cp_response));
		snprintf(cp_command, sizeof(cp_command),
			 "RECORDING %s PURGE %s",
			 logptr->recording_name,
			 qid_string);
		cpcmd(cp_command, cp_response, sizeof(cp_response), NULL);
	}

	return rc;
}


static int vmlogrdr_open (struct inode *inode, struct file *filp)
{
	int dev_num = 0;
	struct vmlogrdr_priv_t * logptr = NULL;
	int connect_rc = 0;
	int ret;

	dev_num = iminor(inode);
	if (dev_num >= MAXMINOR)
		return -ENODEV;
	logptr = &sys_ser[dev_num];

	/*
	 * only allow for blocking reads to be open
	 */
	if (filp->f_flags & O_NONBLOCK)
		return -EOPNOTSUPP;

	/* Besure this device hasn't already been opened */
	spin_lock_bh(&logptr->priv_lock);
	if (logptr->dev_in_use)	{
		spin_unlock_bh(&logptr->priv_lock);
		return -EBUSY;
	}
	logptr->dev_in_use = 1;
	logptr->connection_established = 0;
	logptr->iucv_path_severed = 0;
	atomic_set(&logptr->receive_ready, 0);
	logptr->buffer_free = 1;
	spin_unlock_bh(&logptr->priv_lock);

	/* set the file options */
	filp->private_data = logptr;

	/* start recording for this service*/
	if (logptr->autorecording) {
		ret = vmlogrdr_recording(logptr,1,logptr->autopurge);
		if (ret)
			pr_warn("vmlogrdr: failed to start recording automatically\n");
	}

	/* create connection to the system service */
	logptr->path = iucv_path_alloc(10, 0, GFP_KERNEL);
	if (!logptr->path)
		goto out_dev;
	connect_rc = iucv_path_connect(logptr->path, &vmlogrdr_iucv_handler,
				       logptr->system_service, NULL, NULL,
				       logptr);
	if (connect_rc) {
		pr_err("vmlogrdr: iucv connection to %s "
		       "failed with rc %i \n",
		       logptr->system_service, connect_rc);
		goto out_path;
	}

	/* We've issued the connect and now we must wait for a
	 * ConnectionComplete or ConnectinSevered Interrupt
	 * before we can continue to process.
	 */
	wait_event(conn_wait_queue, (logptr->connection_established)
		   || (logptr->iucv_path_severed));
	if (logptr->iucv_path_severed)
		goto out_record;
	nonseekable_open(inode, filp);
	return 0;

out_record:
	if (logptr->autorecording)
		vmlogrdr_recording(logptr,0,logptr->autopurge);
out_path:
	kfree(logptr->path);	/* kfree(NULL) is ok. */
	logptr->path = NULL;
out_dev:
	logptr->dev_in_use = 0;
	return -EIO;
}


static int vmlogrdr_release (struct inode *inode, struct file *filp)
{
	int ret;

	struct vmlogrdr_priv_t * logptr = filp->private_data;

	iucv_path_sever(logptr->path, NULL);
	kfree(logptr->path);
	logptr->path = NULL;
	if (logptr->autorecording) {
		ret = vmlogrdr_recording(logptr,0,logptr->autopurge);
		if (ret)
			pr_warn("vmlogrdr: failed to stop recording automatically\n");
	}
	logptr->dev_in_use = 0;

	return 0;
}


static int vmlogrdr_receive_data(struct vmlogrdr_priv_t *priv)
{
	int rc, *temp;
	/* we need to keep track of two data sizes here:
	 * The number of bytes we need to receive from iucv and
	 * the total number of bytes we actually write into the buffer.
	 */
	int user_data_count, iucv_data_count;
	char * buffer;

	if (atomic_read(&priv->receive_ready)) {
		spin_lock_bh(&priv->priv_lock);
		if (priv->residual_length){
			/* receive second half of a record */
			iucv_data_count = priv->residual_length;
			user_data_count = 0;
			buffer = priv->buffer;
		} else {
			/* receive a new record:
			 * We need to return the total length of the record
                         * + size of FENCE in the first 4 bytes of the buffer.
		         */
			iucv_data_count = priv->local_interrupt_buffer.length;
			user_data_count = sizeof(int);
			temp = (int*)priv->buffer;
			*temp= iucv_data_count + sizeof(FENCE);
			buffer = priv->buffer + sizeof(int);
		}
		/*
		 * If the record is bigger than our buffer, we receive only
		 * a part of it. We can get the rest later.
		 */
		if (iucv_data_count > NET_BUFFER_SIZE)
			iucv_data_count = NET_BUFFER_SIZE;
		rc = iucv_message_receive(priv->path,
					  &priv->local_interrupt_buffer,
					  0, buffer, iucv_data_count,
					  &priv->residual_length);
		spin_unlock_bh(&priv->priv_lock);
		/* An rc of 5 indicates that the record was bigger than
		 * the buffer, which is OK for us. A 9 indicates that the
		 * record was purged befor we could receive it.
		 */
		if (rc == 5)
			rc = 0;
		if (rc == 9)
			atomic_set(&priv->receive_ready, 0);
	} else {
		rc = 1;
	}
	if (!rc) {
		priv->buffer_free = 0;
 		user_data_count += iucv_data_count;
		priv->current_position = priv->buffer;
		if (priv->residual_length == 0){
			/* the whole record has been captured,
			 * now add the fence */
			atomic_dec(&priv->receive_ready);
			buffer = priv->buffer + user_data_count;
			memcpy(buffer, FENCE, sizeof(FENCE));
			user_data_count += sizeof(FENCE);
		}
		priv->remaining = user_data_count;
	}

	return rc;
}


static ssize_t vmlogrdr_read(struct file *filp, char __user *data,
			     size_t count, loff_t * ppos)
{
	int rc;
	struct vmlogrdr_priv_t * priv = filp->private_data;

	while (priv->buffer_free) {
		rc = vmlogrdr_receive_data(priv);
		if (rc) {
			rc = wait_event_interruptible(read_wait_queue,
					atomic_read(&priv->receive_ready));
			if (rc)
				return rc;
		}
	}
	/* copy only up to end of record */
	if (count > priv->remaining)
		count = priv->remaining;

	if (copy_to_user(data, priv->current_position, count))
		return -EFAULT;

	*ppos += count;
	priv->current_position += count;
	priv->remaining -= count;

	/* if all data has been transferred, set buffer free */
	if (priv->remaining == 0)
		priv->buffer_free = 1;

	return count;
}

static ssize_t vmlogrdr_autopurge_store(struct device * dev,
					struct device_attribute *attr,
					const char * buf, size_t count)
{
	struct vmlogrdr_priv_t *priv = dev_get_drvdata(dev);
	ssize_t ret = count;

	switch (buf[0]) {
	case '0':
		priv->autopurge=0;
		break;
	case '1':
		priv->autopurge=1;
		break;
	default:
		ret = -EINVAL;
	}
	return ret;
}


static ssize_t vmlogrdr_autopurge_show(struct device *dev,
				       struct device_attribute *attr,
				       char *buf)
{
	struct vmlogrdr_priv_t *priv = dev_get_drvdata(dev);
	return sprintf(buf, "%u\n", priv->autopurge);
}


static DEVICE_ATTR(autopurge, 0644, vmlogrdr_autopurge_show,
		   vmlogrdr_autopurge_store);


static ssize_t vmlogrdr_purge_store(struct device * dev,
				    struct device_attribute *attr,
				    const char * buf, size_t count)
{

	char cp_command[80];
	char cp_response[80];
	struct vmlogrdr_priv_t *priv = dev_get_drvdata(dev);

	if (buf[0] != '1')
		return -EINVAL;

	memset(cp_command, 0x00, sizeof(cp_command));
	memset(cp_response, 0x00, sizeof(cp_response));

        /*
	 * The recording command needs to be called with option QID
	 * for guests that have previlege classes A or B.
	 * Other guests will not recognize the command and we have to
	 * issue the same command without the QID parameter.
	 */

	if (recording_class_AB)
		snprintf(cp_command, sizeof(cp_command),
			 "RECORDING %s PURGE QID * ",
			 priv->recording_name);
	else
		snprintf(cp_command, sizeof(cp_command),
			 "RECORDING %s PURGE ",
			 priv->recording_name);

	cpcmd(cp_command, cp_response, sizeof(cp_response), NULL);

	return count;
}


static DEVICE_ATTR(purge, 0200, NULL, vmlogrdr_purge_store);


static ssize_t vmlogrdr_autorecording_store(struct device *dev,
					    struct device_attribute *attr,
					    const char *buf, size_t count)
{
	struct vmlogrdr_priv_t *priv = dev_get_drvdata(dev);
	ssize_t ret = count;

	switch (buf[0]) {
	case '0':
		priv->autorecording=0;
		break;
	case '1':
		priv->autorecording=1;
		break;
	default:
		ret = -EINVAL;
	}
	return ret;
}


static ssize_t vmlogrdr_autorecording_show(struct device *dev,
					   struct device_attribute *attr,
					   char *buf)
{
	struct vmlogrdr_priv_t *priv = dev_get_drvdata(dev);
	return sprintf(buf, "%u\n", priv->autorecording);
}


static DEVICE_ATTR(autorecording, 0644, vmlogrdr_autorecording_show,
		   vmlogrdr_autorecording_store);


static ssize_t vmlogrdr_recording_store(struct device * dev,
					struct device_attribute *attr,
					const char * buf, size_t count)
{
	struct vmlogrdr_priv_t *priv = dev_get_drvdata(dev);
	ssize_t ret;

	switch (buf[0]) {
	case '0':
		ret = vmlogrdr_recording(priv,0,0);
		break;
	case '1':
		ret = vmlogrdr_recording(priv,1,0);
		break;
	default:
		ret = -EINVAL;
	}
	if (ret)
		return ret;
	else
		return count;

}


static DEVICE_ATTR(recording, 0200, NULL, vmlogrdr_recording_store);


static ssize_t recording_status_show(struct device_driver *driver, char *buf)
{
	static const char cp_command[] = "QUERY RECORDING ";
	int len;

	cpcmd(cp_command, buf, 4096, NULL);
	len = strlen(buf);
	return len;
}
static DRIVER_ATTR_RO(recording_status);
static struct attribute *vmlogrdr_drv_attrs[] = {
	&driver_attr_recording_status.attr,
	NULL,
};
static struct attribute_group vmlogrdr_drv_attr_group = {
	.attrs = vmlogrdr_drv_attrs,
};
static const struct attribute_group *vmlogrdr_drv_attr_groups[] = {
	&vmlogrdr_drv_attr_group,
	NULL,
};

static struct attribute *vmlogrdr_attrs[] = {
	&dev_attr_autopurge.attr,
	&dev_attr_purge.attr,
	&dev_attr_autorecording.attr,
	&dev_attr_recording.attr,
	NULL,
};
static struct attribute_group vmlogrdr_attr_group = {
	.attrs = vmlogrdr_attrs,
};
static const struct attribute_group *vmlogrdr_attr_groups[] = {
	&vmlogrdr_attr_group,
	NULL,
};

static int vmlogrdr_pm_prepare(struct device *dev)
{
	int rc;
	struct vmlogrdr_priv_t *priv = dev_get_drvdata(dev);

	rc = 0;
	if (priv) {
		spin_lock_bh(&priv->priv_lock);
		if (priv->dev_in_use)
			rc = -EBUSY;
		spin_unlock_bh(&priv->priv_lock);
	}
	if (rc)
		pr_err("vmlogrdr: device %s is busy. Refuse to suspend.\n",
		       dev_name(dev));
	return rc;
}


static const struct dev_pm_ops vmlogrdr_pm_ops = {
	.prepare = vmlogrdr_pm_prepare,
};

static struct class *vmlogrdr_class;
static struct device_driver vmlogrdr_driver = {
	.name = "vmlogrdr",
	.bus  = &iucv_bus,
	.pm = &vmlogrdr_pm_ops,
	.groups = vmlogrdr_drv_attr_groups,
};

static int vmlogrdr_register_driver(void)
{
	int ret;

	/* Register with iucv driver */
	ret = iucv_register(&vmlogrdr_iucv_handler, 1);
	if (ret)
		goto out;

	ret = driver_register(&vmlogrdr_driver);
	if (ret)
		goto out_iucv;

	vmlogrdr_class = class_create(THIS_MODULE, "vmlogrdr");
	if (IS_ERR(vmlogrdr_class)) {
		ret = PTR_ERR(vmlogrdr_class);
		vmlogrdr_class = NULL;
		goto out_driver;
	}
	return 0;

out_driver:
	driver_unregister(&vmlogrdr_driver);
out_iucv:
	iucv_unregister(&vmlogrdr_iucv_handler, 1);
out:
	return ret;
}


static void vmlogrdr_unregister_driver(void)
{
	class_destroy(vmlogrdr_class);
	vmlogrdr_class = NULL;
	driver_unregister(&vmlogrdr_driver);
	iucv_unregister(&vmlogrdr_iucv_handler, 1);
}


static int vmlogrdr_register_device(struct vmlogrdr_priv_t *priv)
{
	struct device *dev;
	int ret;

	dev = kzalloc(sizeof(struct device), GFP_KERNEL);
	if (dev) {
		dev_set_name(dev, "%s", priv->internal_name);
		dev->bus = &iucv_bus;
		dev->parent = iucv_root;
		dev->driver = &vmlogrdr_driver;
		dev->groups = vmlogrdr_attr_groups;
		dev_set_drvdata(dev, priv);
		/*
		 * The release function could be called after the
		 * module has been unloaded. It's _only_ task is to
		 * free the struct. Therefore, we specify kfree()
		 * directly here. (Probably a little bit obfuscating
		 * but legitime ...).
		 */
		dev->release = (void (*)(struct device *))kfree;
	} else
		return -ENOMEM;
	ret = device_register(dev);
	if (ret) {
		put_device(dev);
		return ret;
	}

	priv->class_device = device_create(vmlogrdr_class, dev,
					   MKDEV(vmlogrdr_major,
						 priv->minor_num),
					   priv, "%s", dev_name(dev));
	if (IS_ERR(priv->class_device)) {
		ret = PTR_ERR(priv->class_device);
		priv->class_device=NULL;
		device_unregister(dev);
		return ret;
	}
	priv->device = dev;
	return 0;
}


static int vmlogrdr_unregister_device(struct vmlogrdr_priv_t *priv)
{
	device_destroy(vmlogrdr_class, MKDEV(vmlogrdr_major, priv->minor_num));
	if (priv->device != NULL) {
		device_unregister(priv->device);
		priv->device=NULL;
	}
	return 0;
}


static int vmlogrdr_register_cdev(dev_t dev)
{
	int rc = 0;
	vmlogrdr_cdev = cdev_alloc();
	if (!vmlogrdr_cdev) {
		return -ENOMEM;
	}
	vmlogrdr_cdev->owner = THIS_MODULE;
	vmlogrdr_cdev->ops = &vmlogrdr_fops;
	rc = cdev_add(vmlogrdr_cdev, dev, MAXMINOR);
	if (!rc)
		return 0;

	// cleanup: cdev is not fully registered, no cdev_del here!
	kobject_put(&vmlogrdr_cdev->kobj);
	vmlogrdr_cdev=NULL;
	return rc;
}


static void vmlogrdr_cleanup(void)
{
        int i;

	if (vmlogrdr_cdev) {
		cdev_del(vmlogrdr_cdev);
		vmlogrdr_cdev=NULL;
	}
	for (i=0; i < MAXMINOR; ++i ) {
		vmlogrdr_unregister_device(&sys_ser[i]);
		free_page((unsigned long)sys_ser[i].buffer);
	}
	vmlogrdr_unregister_driver();
	if (vmlogrdr_major) {
		unregister_chrdev_region(MKDEV(vmlogrdr_major, 0), MAXMINOR);
		vmlogrdr_major=0;
	}
}


static int __init vmlogrdr_init(void)
{
	int rc;
	int i;
	dev_t dev;

	if (! MACHINE_IS_VM) {
		pr_err("not running under VM, driver not loaded.\n");
		return -ENODEV;
	}

        recording_class_AB = vmlogrdr_get_recording_class_AB();

	rc = alloc_chrdev_region(&dev, 0, MAXMINOR, "vmlogrdr");
	if (rc)
		return rc;
	vmlogrdr_major = MAJOR(dev);

	rc=vmlogrdr_register_driver();
	if (rc)
		goto cleanup;

	for (i=0; i < MAXMINOR; ++i ) {
		sys_ser[i].buffer = (char *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
		if (!sys_ser[i].buffer) {
			rc = -ENOMEM;
			break;
		}
		sys_ser[i].current_position = sys_ser[i].buffer;
		rc=vmlogrdr_register_device(&sys_ser[i]);
		if (rc)
			break;
	}
	if (rc)
		goto cleanup;

	rc = vmlogrdr_register_cdev(dev);
	if (rc)
		goto cleanup;
	return 0;

cleanup:
	vmlogrdr_cleanup();
	return rc;
}


static void __exit vmlogrdr_exit(void)
{
	vmlogrdr_cleanup();
	return;
}


module_init(vmlogrdr_init);
module_exit(vmlogrdr_exit);