summaryrefslogtreecommitdiff
path: root/arch/s390/mm/extmem.c
blob: 580fc64cc735f343f2576baaba0bebb8eef2b3e9 (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
/*
 * File...........: arch/s390/mm/extmem.c
 * Author(s)......: Carsten Otte <cotte@de.ibm.com>
 * 		    Rob M van der Heij <rvdheij@nl.ibm.com>
 * 		    Steven Shultz <shultzss@us.ibm.com>
 * Bugreports.to..: <Linux390@de.ibm.com>
 * (C) IBM Corporation 2002-2004
 */

#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/spinlock.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/bootmem.h>
#include <linux/ctype.h>
#include <linux/ioport.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/ebcdic.h>
#include <asm/errno.h>
#include <asm/extmem.h>
#include <asm/cpcmd.h>
#include <asm/setup.h>

#define DCSS_DEBUG	/* Debug messages on/off */

#define DCSS_NAME "extmem"
#ifdef DCSS_DEBUG
#define PRINT_DEBUG(x...)	printk(KERN_DEBUG DCSS_NAME " debug:" x)
#else
#define PRINT_DEBUG(x...)   do {} while (0)
#endif
#define PRINT_INFO(x...)	printk(KERN_INFO DCSS_NAME " info:" x)
#define PRINT_WARN(x...)	printk(KERN_WARNING DCSS_NAME " warning:" x)
#define PRINT_ERR(x...)		printk(KERN_ERR DCSS_NAME " error:" x)


#define DCSS_LOADSHR    0x00
#define DCSS_LOADNSR    0x04
#define DCSS_PURGESEG   0x08
#define DCSS_FINDSEG    0x0c
#define DCSS_LOADNOLY   0x10
#define DCSS_SEGEXT     0x18
#define DCSS_LOADSHRX	0x20
#define DCSS_LOADNSRX	0x24
#define DCSS_FINDSEGX	0x2c
#define DCSS_SEGEXTX	0x38
#define DCSS_FINDSEGA   0x0c

struct qrange {
	unsigned long  start; /* last byte type */
	unsigned long  end;   /* last byte reserved */
};

struct qout64 {
	unsigned long segstart;
	unsigned long segend;
	int segcnt;
	int segrcnt;
	struct qrange range[6];
};

#ifdef CONFIG_64BIT
struct qrange_old {
	unsigned int start; /* last byte type */
	unsigned int end;   /* last byte reserved */
};

/* output area format for the Diag x'64' old subcode x'18' */
struct qout64_old {
	int segstart;
	int segend;
	int segcnt;
	int segrcnt;
	struct qrange_old range[6];
};
#endif

struct qin64 {
	char qopcode;
	char rsrv1[3];
	char qrcode;
	char rsrv2[3];
	char qname[8];
	unsigned int qoutptr;
	short int qoutlen;
};

struct dcss_segment {
	struct list_head list;
	char dcss_name[8];
	char res_name[15];
	unsigned long start_addr;
	unsigned long end;
	atomic_t ref_count;
	int do_nonshared;
	unsigned int vm_segtype;
	struct qrange range[6];
	int segcnt;
	struct resource *res;
};

static DEFINE_MUTEX(dcss_lock);
static LIST_HEAD(dcss_list);
static char *segtype_string[] = { "SW", "EW", "SR", "ER", "SN", "EN", "SC",
					"EW/EN-MIXED" };
static int loadshr_scode, loadnsr_scode, findseg_scode;
static int segext_scode, purgeseg_scode;
static int scode_set;

/* set correct Diag x'64' subcodes. */
static int
dcss_set_subcodes(void)
{
#ifdef CONFIG_64BIT
	char *name = kmalloc(8 * sizeof(char), GFP_DMA);
	unsigned long rx, ry;
	int rc;

	if (name == NULL)
		return -ENOMEM;

	rx = (unsigned long) name;
	ry = DCSS_FINDSEGX;

	strcpy(name, "dummy");
	asm volatile(
		"	diag	%0,%1,0x64\n"
		"0:	ipm	%2\n"
		"	srl	%2,28\n"
		"	j	2f\n"
		"1:	la	%2,3\n"
		"2:\n"
		EX_TABLE(0b, 1b)
		: "+d" (rx), "+d" (ry), "=d" (rc) : : "cc");

	kfree(name);
	/* Diag x'64' new subcodes are supported, set to new subcodes */
	if (rc != 3) {
		loadshr_scode = DCSS_LOADSHRX;
		loadnsr_scode = DCSS_LOADNSRX;
		purgeseg_scode = DCSS_PURGESEG;
		findseg_scode = DCSS_FINDSEGX;
		segext_scode = DCSS_SEGEXTX;
		return 0;
	}
#endif
	/* Diag x'64' new subcodes are not supported, set to old subcodes */
	loadshr_scode = DCSS_LOADNOLY;
	loadnsr_scode = DCSS_LOADNSR;
	purgeseg_scode = DCSS_PURGESEG;
	findseg_scode = DCSS_FINDSEG;
	segext_scode = DCSS_SEGEXT;
	return 0;
}

/*
 * Create the 8 bytes, ebcdic VM segment name from
 * an ascii name.
 */
static void
dcss_mkname(char *name, char *dcss_name)
{
	int i;

	for (i = 0; i < 8; i++) {
		if (name[i] == '\0')
			break;
		dcss_name[i] = toupper(name[i]);
	};
	for (; i < 8; i++)
		dcss_name[i] = ' ';
	ASCEBC(dcss_name, 8);
}


/*
 * search all segments in dcss_list, and return the one
 * namend *name. If not found, return NULL.
 */
static struct dcss_segment *
segment_by_name (char *name)
{
	char dcss_name[9];
	struct list_head *l;
	struct dcss_segment *tmp, *retval = NULL;

	BUG_ON(!mutex_is_locked(&dcss_lock));
	dcss_mkname (name, dcss_name);
	list_for_each (l, &dcss_list) {
		tmp = list_entry (l, struct dcss_segment, list);
		if (memcmp(tmp->dcss_name, dcss_name, 8) == 0) {
			retval = tmp;
			break;
		}
	}
	return retval;
}


/*
 * Perform a function on a dcss segment.
 */
static inline int
dcss_diag(int *func, void *parameter,
           unsigned long *ret1, unsigned long *ret2)
{
	unsigned long rx, ry;
	int rc;

	if (scode_set == 0) {
		rc = dcss_set_subcodes();
		if (rc < 0)
			return rc;
		scode_set = 1;
	}
	rx = (unsigned long) parameter;
	ry = (unsigned long) *func;

#ifdef CONFIG_64BIT
	/* 64-bit Diag x'64' new subcode, keep in 64-bit addressing mode */
	if (*func > DCSS_SEGEXT)
		asm volatile(
			"	diag	%0,%1,0x64\n"
			"	ipm	%2\n"
			"	srl	%2,28\n"
			: "+d" (rx), "+d" (ry), "=d" (rc) : : "cc");
	/* 31-bit Diag x'64' old subcode, switch to 31-bit addressing mode */
	else
		asm volatile(
			"	sam31\n"
			"	diag	%0,%1,0x64\n"
			"	sam64\n"
			"	ipm	%2\n"
			"	srl	%2,28\n"
			: "+d" (rx), "+d" (ry), "=d" (rc) : : "cc");
#else
	asm volatile(
		"	diag	%0,%1,0x64\n"
		"	ipm	%2\n"
		"	srl	%2,28\n"
		: "+d" (rx), "+d" (ry), "=d" (rc) : : "cc");
#endif
	*ret1 = rx;
	*ret2 = ry;
	return rc;
}

static inline int
dcss_diag_translate_rc (int vm_rc) {
	if (vm_rc == 44)
		return -ENOENT;
	return -EIO;
}


/* do a diag to get info about a segment.
 * fills start_address, end and vm_segtype fields
 */
static int
query_segment_type (struct dcss_segment *seg)
{
	struct qin64  *qin = kmalloc (sizeof(struct qin64), GFP_DMA);
	struct qout64 *qout = kmalloc (sizeof(struct qout64), GFP_DMA);

	int diag_cc, rc, i;
	unsigned long dummy, vmrc;

	if ((qin == NULL) || (qout == NULL)) {
		rc = -ENOMEM;
		goto out_free;
	}

	/* initialize diag input parameters */
	qin->qopcode = DCSS_FINDSEGA;
	qin->qoutptr = (unsigned long) qout;
	qin->qoutlen = sizeof(struct qout64);
	memcpy (qin->qname, seg->dcss_name, 8);

	diag_cc = dcss_diag(&segext_scode, qin, &dummy, &vmrc);

	if (diag_cc < 0) {
		rc = diag_cc;
		goto out_free;
	}
	if (diag_cc > 1) {
		PRINT_WARN ("segment_type: diag returned error %ld\n", vmrc);
		rc = dcss_diag_translate_rc (vmrc);
		goto out_free;
	}

#ifdef CONFIG_64BIT
	/* Only old format of output area of Diagnose x'64' is supported,
	   copy data for the new format. */
	if (segext_scode == DCSS_SEGEXT) {
		struct qout64_old *qout_old;
		qout_old = kzalloc(sizeof(struct qout64_old), GFP_DMA);
		if (qout_old == NULL) {
			rc = -ENOMEM;
			goto out_free;
		}
		memcpy(qout_old, qout, sizeof(struct qout64_old));
		qout->segstart = (unsigned long) qout_old->segstart;
		qout->segend = (unsigned long) qout_old->segend;
		qout->segcnt = qout_old->segcnt;
		qout->segrcnt = qout_old->segrcnt;

		if (qout->segcnt > 6)
			qout->segrcnt = 6;
		for (i = 0; i < qout->segrcnt; i++) {
			qout->range[i].start =
				(unsigned long) qout_old->range[i].start;
			qout->range[i].end =
				(unsigned long) qout_old->range[i].end;
		}
		kfree(qout_old);
	}
#endif
	if (qout->segcnt > 6) {
		rc = -ENOTSUPP;
		goto out_free;
	}

	if (qout->segcnt == 1) {
		seg->vm_segtype = qout->range[0].start & 0xff;
	} else {
		/* multi-part segment. only one type supported here:
		    - all parts are contiguous
		    - all parts are either EW or EN type
		    - maximum 6 parts allowed */
		unsigned long start = qout->segstart >> PAGE_SHIFT;
		for (i=0; i<qout->segcnt; i++) {
			if (((qout->range[i].start & 0xff) != SEG_TYPE_EW) &&
			    ((qout->range[i].start & 0xff) != SEG_TYPE_EN)) {
				rc = -ENOTSUPP;
				goto out_free;
			}
			if (start != qout->range[i].start >> PAGE_SHIFT) {
				rc = -ENOTSUPP;
				goto out_free;
			}
			start = (qout->range[i].end >> PAGE_SHIFT) + 1;
		}
		seg->vm_segtype = SEG_TYPE_EWEN;
	}

	/* analyze diag output and update seg */
	seg->start_addr = qout->segstart;
	seg->end = qout->segend;

	memcpy (seg->range, qout->range, 6*sizeof(struct qrange));
	seg->segcnt = qout->segcnt;

	rc = 0;

 out_free:
	kfree(qin);
	kfree(qout);
	return rc;
}

/*
 * get info about a segment
 * possible return values:
 * -ENOSYS  : we are not running on VM
 * -EIO     : could not perform query diagnose
 * -ENOENT  : no such segment
 * -ENOTSUPP: multi-part segment cannot be used with linux
 * -ENOSPC  : segment cannot be used (overlaps with storage)
 * -ENOMEM  : out of memory
 * 0 .. 6   : type of segment as defined in include/asm-s390/extmem.h
 */
int
segment_type (char* name)
{
	int rc;
	struct dcss_segment seg;

	if (!MACHINE_IS_VM)
		return -ENOSYS;

	dcss_mkname(name, seg.dcss_name);
	rc = query_segment_type (&seg);
	if (rc < 0)
		return rc;
	return seg.vm_segtype;
}

/*
 * check if segment collides with other segments that are currently loaded
 * returns 1 if this is the case, 0 if no collision was found
 */
static int
segment_overlaps_others (struct dcss_segment *seg)
{
	struct list_head *l;
	struct dcss_segment *tmp;

	BUG_ON(!mutex_is_locked(&dcss_lock));
	list_for_each(l, &dcss_list) {
		tmp = list_entry(l, struct dcss_segment, list);
		if ((tmp->start_addr >> 20) > (seg->end >> 20))
			continue;
		if ((tmp->end >> 20) < (seg->start_addr >> 20))
			continue;
		if (seg == tmp)
			continue;
		return 1;
	}
	return 0;
}

/*
 * real segment loading function, called from segment_load
 */
static int
__segment_load (char *name, int do_nonshared, unsigned long *addr, unsigned long *end)
{
	struct dcss_segment *seg = kmalloc(sizeof(struct dcss_segment),
			GFP_DMA);
	int rc, diag_cc;
	unsigned long start_addr, end_addr, dummy;

	if (seg == NULL) {
		rc = -ENOMEM;
		goto out;
	}
	dcss_mkname (name, seg->dcss_name);
	rc = query_segment_type (seg);
	if (rc < 0)
		goto out_free;

	if (loadshr_scode == DCSS_LOADSHRX) {
		if (segment_overlaps_others(seg)) {
			rc = -EBUSY;
			goto out_free;
		}
	}

	rc = vmem_add_mapping(seg->start_addr, seg->end - seg->start_addr + 1);

	if (rc)
		goto out_free;

	seg->res = kzalloc(sizeof(struct resource), GFP_KERNEL);
	if (seg->res == NULL) {
		rc = -ENOMEM;
		goto out_shared;
	}
	seg->res->flags = IORESOURCE_BUSY | IORESOURCE_MEM;
	seg->res->start = seg->start_addr;
	seg->res->end = seg->end;
	memcpy(&seg->res_name, seg->dcss_name, 8);
	EBCASC(seg->res_name, 8);
	seg->res_name[8] = '\0';
	strncat(seg->res_name, " (DCSS)", 7);
	seg->res->name = seg->res_name;
	rc = seg->vm_segtype;
	if (rc == SEG_TYPE_SC ||
	    ((rc == SEG_TYPE_SR || rc == SEG_TYPE_ER) && !do_nonshared))
		seg->res->flags |= IORESOURCE_READONLY;
	if (request_resource(&iomem_resource, seg->res)) {
		rc = -EBUSY;
		kfree(seg->res);
		goto out_shared;
	}

	if (do_nonshared)
		diag_cc = dcss_diag(&loadnsr_scode, seg->dcss_name,
				&start_addr, &end_addr);
	else
		diag_cc = dcss_diag(&loadshr_scode, seg->dcss_name,
				&start_addr, &end_addr);
	if (diag_cc < 0) {
		dcss_diag(&purgeseg_scode, seg->dcss_name,
				&dummy, &dummy);
		rc = diag_cc;
		goto out_resource;
	}
	if (diag_cc > 1) {
		PRINT_WARN ("segment_load: could not load segment %s - "
				"diag returned error (%ld)\n",
				name, end_addr);
		rc = dcss_diag_translate_rc(end_addr);
		dcss_diag(&purgeseg_scode, seg->dcss_name,
				&dummy, &dummy);
		goto out_resource;
	}
	seg->start_addr = start_addr;
	seg->end = end_addr;
	seg->do_nonshared = do_nonshared;
	atomic_set(&seg->ref_count, 1);
	list_add(&seg->list, &dcss_list);
	*addr = seg->start_addr;
	*end  = seg->end;
	if (do_nonshared)
		PRINT_INFO ("segment_load: loaded segment %s range %p .. %p "
				"type %s in non-shared mode\n", name,
				(void*)seg->start_addr, (void*)seg->end,
				segtype_string[seg->vm_segtype]);
	else {
		PRINT_INFO ("segment_load: loaded segment %s range %p .. %p "
				"type %s in shared mode\n", name,
				(void*)seg->start_addr, (void*)seg->end,
				segtype_string[seg->vm_segtype]);
	}
	goto out;
 out_resource:
	release_resource(seg->res);
	kfree(seg->res);
 out_shared:
	vmem_remove_mapping(seg->start_addr, seg->end - seg->start_addr + 1);
 out_free:
	kfree(seg);
 out:
	return rc;
}

/*
 * this function loads a DCSS segment
 * name         : name of the DCSS
 * do_nonshared : 0 indicates that the dcss should be shared with other linux images
 *                1 indicates that the dcss should be exclusive for this linux image
 * addr         : will be filled with start address of the segment
 * end          : will be filled with end address of the segment
 * return values:
 * -ENOSYS  : we are not running on VM
 * -EIO     : could not perform query or load diagnose
 * -ENOENT  : no such segment
 * -ENOTSUPP: multi-part segment cannot be used with linux
 * -ENOSPC  : segment cannot be used (overlaps with storage)
 * -EBUSY   : segment can temporarily not be used (overlaps with dcss)
 * -ERANGE  : segment cannot be used (exceeds kernel mapping range)
 * -EPERM   : segment is currently loaded with incompatible permissions
 * -ENOMEM  : out of memory
 * 0 .. 6   : type of segment as defined in include/asm-s390/extmem.h
 */
int
segment_load (char *name, int do_nonshared, unsigned long *addr,
		unsigned long *end)
{
	struct dcss_segment *seg;
	int rc;

	if (!MACHINE_IS_VM)
		return -ENOSYS;

	mutex_lock(&dcss_lock);
	seg = segment_by_name (name);
	if (seg == NULL)
		rc = __segment_load (name, do_nonshared, addr, end);
	else {
		if (do_nonshared == seg->do_nonshared) {
			atomic_inc(&seg->ref_count);
			*addr = seg->start_addr;
			*end  = seg->end;
			rc    = seg->vm_segtype;
		} else {
			*addr = *end = 0;
			rc    = -EPERM;
		}
	}
	mutex_unlock(&dcss_lock);
	return rc;
}

/*
 * this function modifies the shared state of a DCSS segment. note that
 * name         : name of the DCSS
 * do_nonshared : 0 indicates that the dcss should be shared with other linux images
 *                1 indicates that the dcss should be exclusive for this linux image
 * return values:
 * -EIO     : could not perform load diagnose (segment gone!)
 * -ENOENT  : no such segment (segment gone!)
 * -EAGAIN  : segment is in use by other exploiters, try later
 * -EINVAL  : no segment with the given name is currently loaded - name invalid
 * -EBUSY   : segment can temporarily not be used (overlaps with dcss)
 * 0	    : operation succeeded
 */
int
segment_modify_shared (char *name, int do_nonshared)
{
	struct dcss_segment *seg;
	unsigned long start_addr, end_addr, dummy;
	int rc, diag_cc;

	mutex_lock(&dcss_lock);
	seg = segment_by_name (name);
	if (seg == NULL) {
		rc = -EINVAL;
		goto out_unlock;
	}
	if (do_nonshared == seg->do_nonshared) {
		PRINT_INFO ("segment_modify_shared: not reloading segment %s"
				" - already in requested mode\n",name);
		rc = 0;
		goto out_unlock;
	}
	if (atomic_read (&seg->ref_count) != 1) {
		PRINT_WARN ("segment_modify_shared: not reloading segment %s - "
				"segment is in use by other driver(s)\n",name);
		rc = -EAGAIN;
		goto out_unlock;
	}
	release_resource(seg->res);
	if (do_nonshared)
		seg->res->flags &= ~IORESOURCE_READONLY;
	else
		if (seg->vm_segtype == SEG_TYPE_SR ||
		    seg->vm_segtype == SEG_TYPE_ER)
			seg->res->flags |= IORESOURCE_READONLY;

	if (request_resource(&iomem_resource, seg->res)) {
		PRINT_WARN("segment_modify_shared: could not reload segment %s"
			   " - overlapping resources\n", name);
		rc = -EBUSY;
		kfree(seg->res);
		goto out_del_mem;
	}

	dcss_diag(&purgeseg_scode, seg->dcss_name, &dummy, &dummy);
	if (do_nonshared)
		diag_cc = dcss_diag(&loadnsr_scode, seg->dcss_name,
				&start_addr, &end_addr);
	else
		diag_cc = dcss_diag(&loadshr_scode, seg->dcss_name,
				&start_addr, &end_addr);
	if (diag_cc < 0) {
		rc = diag_cc;
		goto out_del_res;
	}
	if (diag_cc > 1) {
		PRINT_WARN ("segment_modify_shared: could not reload segment %s"
				" - diag returned error (%ld)\n",
				name, end_addr);
		rc = dcss_diag_translate_rc(end_addr);
		goto out_del_res;
	}
	seg->start_addr = start_addr;
	seg->end = end_addr;
	seg->do_nonshared = do_nonshared;
	rc = 0;
	goto out_unlock;
 out_del_res:
	release_resource(seg->res);
	kfree(seg->res);
 out_del_mem:
	vmem_remove_mapping(seg->start_addr, seg->end - seg->start_addr + 1);
	list_del(&seg->list);
	dcss_diag(&purgeseg_scode, seg->dcss_name, &dummy, &dummy);
	kfree(seg);
 out_unlock:
	mutex_unlock(&dcss_lock);
	return rc;
}

/*
 * Decrease the use count of a DCSS segment and remove
 * it from the address space if nobody is using it
 * any longer.
 */
void
segment_unload(char *name)
{
	unsigned long dummy;
	struct dcss_segment *seg;

	if (!MACHINE_IS_VM)
		return;

	mutex_lock(&dcss_lock);
	seg = segment_by_name (name);
	if (seg == NULL) {
		PRINT_ERR ("could not find segment %s in segment_unload, "
				"please report to linux390@de.ibm.com\n",name);
		goto out_unlock;
	}
	if (atomic_dec_return(&seg->ref_count) != 0)
		goto out_unlock;
	release_resource(seg->res);
	kfree(seg->res);
	vmem_remove_mapping(seg->start_addr, seg->end - seg->start_addr + 1);
	list_del(&seg->list);
	dcss_diag(&purgeseg_scode, seg->dcss_name, &dummy, &dummy);
	kfree(seg);
out_unlock:
	mutex_unlock(&dcss_lock);
}

/*
 * save segment content permanently
 */
void
segment_save(char *name)
{
	struct dcss_segment *seg;
	int startpfn = 0;
	int endpfn = 0;
	char cmd1[160];
	char cmd2[80];
	int i, response;

	if (!MACHINE_IS_VM)
		return;

	mutex_lock(&dcss_lock);
	seg = segment_by_name (name);

	if (seg == NULL) {
		PRINT_ERR("could not find segment %s in segment_save, please "
			  "report to linux390@de.ibm.com\n", name);
		goto out;
	}

	startpfn = seg->start_addr >> PAGE_SHIFT;
	endpfn = (seg->end) >> PAGE_SHIFT;
	sprintf(cmd1, "DEFSEG %s", name);
	for (i=0; i<seg->segcnt; i++) {
		sprintf(cmd1+strlen(cmd1), " %lX-%lX %s",
			seg->range[i].start >> PAGE_SHIFT,
			seg->range[i].end >> PAGE_SHIFT,
			segtype_string[seg->range[i].start & 0xff]);
	}
	sprintf(cmd2, "SAVESEG %s", name);
	response = 0;
	cpcmd(cmd1, NULL, 0, &response);
	if (response) {
		PRINT_ERR("segment_save: DEFSEG failed with response code %i\n",
			  response);
		goto out;
	}
	cpcmd(cmd2, NULL, 0, &response);
	if (response) {
		PRINT_ERR("segment_save: SAVESEG failed with response code %i\n",
			  response);
		goto out;
	}
out:
	mutex_unlock(&dcss_lock);
}

/*
 * print appropriate error message for segment_load()/segment_type()
 * return code
 */
void segment_warning(int rc, char *seg_name)
{
	switch (rc) {
	case -ENOENT:
		PRINT_WARN("cannot load/query segment %s, "
			   "does not exist\n", seg_name);
		break;
	case -ENOSYS:
		PRINT_WARN("cannot load/query segment %s, "
			   "not running on VM\n", seg_name);
		break;
	case -EIO:
		PRINT_WARN("cannot load/query segment %s, "
			   "hardware error\n", seg_name);
		break;
	case -ENOTSUPP:
		PRINT_WARN("cannot load/query segment %s, "
			   "is a multi-part segment\n", seg_name);
		break;
	case -ENOSPC:
		PRINT_WARN("cannot load/query segment %s, "
			   "overlaps with storage\n", seg_name);
		break;
	case -EBUSY:
		PRINT_WARN("cannot load/query segment %s, "
			   "overlaps with already loaded dcss\n", seg_name);
		break;
	case -EPERM:
		PRINT_WARN("cannot load/query segment %s, "
			   "already loaded in incompatible mode\n", seg_name);
		break;
	case -ENOMEM:
		PRINT_WARN("cannot load/query segment %s, "
			   "out of memory\n", seg_name);
		break;
	case -ERANGE:
		PRINT_WARN("cannot load/query segment %s, "
			   "exceeds kernel mapping range\n", seg_name);
		break;
	default:
		PRINT_WARN("cannot load/query segment %s, "
			   "return value %i\n", seg_name, rc);
		break;
	}
}

EXPORT_SYMBOL(segment_load);
EXPORT_SYMBOL(segment_unload);
EXPORT_SYMBOL(segment_save);
EXPORT_SYMBOL(segment_type);
EXPORT_SYMBOL(segment_modify_shared);
EXPORT_SYMBOL(segment_warning);