xref: /openbmc/linux/arch/s390/mm/extmem.c (revision 15e47304)
1 /*
2  * Author(s)......: Carsten Otte <cotte@de.ibm.com>
3  * 		    Rob M van der Heij <rvdheij@nl.ibm.com>
4  * 		    Steven Shultz <shultzss@us.ibm.com>
5  * Bugreports.to..: <Linux390@de.ibm.com>
6  * Copyright IBM Corp. 2002, 2004
7  */
8 
9 #define KMSG_COMPONENT "extmem"
10 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
11 
12 #include <linux/kernel.h>
13 #include <linux/string.h>
14 #include <linux/spinlock.h>
15 #include <linux/list.h>
16 #include <linux/slab.h>
17 #include <linux/module.h>
18 #include <linux/bootmem.h>
19 #include <linux/ctype.h>
20 #include <linux/ioport.h>
21 #include <asm/page.h>
22 #include <asm/pgtable.h>
23 #include <asm/ebcdic.h>
24 #include <asm/errno.h>
25 #include <asm/extmem.h>
26 #include <asm/cpcmd.h>
27 #include <asm/setup.h>
28 
29 #define DCSS_LOADSHR    0x00
30 #define DCSS_LOADNSR    0x04
31 #define DCSS_PURGESEG   0x08
32 #define DCSS_FINDSEG    0x0c
33 #define DCSS_LOADNOLY   0x10
34 #define DCSS_SEGEXT     0x18
35 #define DCSS_LOADSHRX	0x20
36 #define DCSS_LOADNSRX	0x24
37 #define DCSS_FINDSEGX	0x2c
38 #define DCSS_SEGEXTX	0x38
39 #define DCSS_FINDSEGA   0x0c
40 
41 struct qrange {
42 	unsigned long  start; /* last byte type */
43 	unsigned long  end;   /* last byte reserved */
44 };
45 
46 struct qout64 {
47 	unsigned long segstart;
48 	unsigned long segend;
49 	int segcnt;
50 	int segrcnt;
51 	struct qrange range[6];
52 };
53 
54 #ifdef CONFIG_64BIT
55 struct qrange_old {
56 	unsigned int start; /* last byte type */
57 	unsigned int end;   /* last byte reserved */
58 };
59 
60 /* output area format for the Diag x'64' old subcode x'18' */
61 struct qout64_old {
62 	int segstart;
63 	int segend;
64 	int segcnt;
65 	int segrcnt;
66 	struct qrange_old range[6];
67 };
68 #endif
69 
70 struct qin64 {
71 	char qopcode;
72 	char rsrv1[3];
73 	char qrcode;
74 	char rsrv2[3];
75 	char qname[8];
76 	unsigned int qoutptr;
77 	short int qoutlen;
78 };
79 
80 struct dcss_segment {
81 	struct list_head list;
82 	char dcss_name[8];
83 	char res_name[15];
84 	unsigned long start_addr;
85 	unsigned long end;
86 	atomic_t ref_count;
87 	int do_nonshared;
88 	unsigned int vm_segtype;
89 	struct qrange range[6];
90 	int segcnt;
91 	struct resource *res;
92 };
93 
94 static DEFINE_MUTEX(dcss_lock);
95 static LIST_HEAD(dcss_list);
96 static char *segtype_string[] = { "SW", "EW", "SR", "ER", "SN", "EN", "SC",
97 					"EW/EN-MIXED" };
98 static int loadshr_scode, loadnsr_scode, findseg_scode;
99 static int segext_scode, purgeseg_scode;
100 static int scode_set;
101 
102 /* set correct Diag x'64' subcodes. */
103 static int
104 dcss_set_subcodes(void)
105 {
106 #ifdef CONFIG_64BIT
107 	char *name = kmalloc(8 * sizeof(char), GFP_KERNEL | GFP_DMA);
108 	unsigned long rx, ry;
109 	int rc;
110 
111 	if (name == NULL)
112 		return -ENOMEM;
113 
114 	rx = (unsigned long) name;
115 	ry = DCSS_FINDSEGX;
116 
117 	strcpy(name, "dummy");
118 	asm volatile(
119 		"	diag	%0,%1,0x64\n"
120 		"0:	ipm	%2\n"
121 		"	srl	%2,28\n"
122 		"	j	2f\n"
123 		"1:	la	%2,3\n"
124 		"2:\n"
125 		EX_TABLE(0b, 1b)
126 		: "+d" (rx), "+d" (ry), "=d" (rc) : : "cc");
127 
128 	kfree(name);
129 	/* Diag x'64' new subcodes are supported, set to new subcodes */
130 	if (rc != 3) {
131 		loadshr_scode = DCSS_LOADSHRX;
132 		loadnsr_scode = DCSS_LOADNSRX;
133 		purgeseg_scode = DCSS_PURGESEG;
134 		findseg_scode = DCSS_FINDSEGX;
135 		segext_scode = DCSS_SEGEXTX;
136 		return 0;
137 	}
138 #endif
139 	/* Diag x'64' new subcodes are not supported, set to old subcodes */
140 	loadshr_scode = DCSS_LOADNOLY;
141 	loadnsr_scode = DCSS_LOADNSR;
142 	purgeseg_scode = DCSS_PURGESEG;
143 	findseg_scode = DCSS_FINDSEG;
144 	segext_scode = DCSS_SEGEXT;
145 	return 0;
146 }
147 
148 /*
149  * Create the 8 bytes, ebcdic VM segment name from
150  * an ascii name.
151  */
152 static void
153 dcss_mkname(char *name, char *dcss_name)
154 {
155 	int i;
156 
157 	for (i = 0; i < 8; i++) {
158 		if (name[i] == '\0')
159 			break;
160 		dcss_name[i] = toupper(name[i]);
161 	};
162 	for (; i < 8; i++)
163 		dcss_name[i] = ' ';
164 	ASCEBC(dcss_name, 8);
165 }
166 
167 
168 /*
169  * search all segments in dcss_list, and return the one
170  * namend *name. If not found, return NULL.
171  */
172 static struct dcss_segment *
173 segment_by_name (char *name)
174 {
175 	char dcss_name[9];
176 	struct list_head *l;
177 	struct dcss_segment *tmp, *retval = NULL;
178 
179 	BUG_ON(!mutex_is_locked(&dcss_lock));
180 	dcss_mkname (name, dcss_name);
181 	list_for_each (l, &dcss_list) {
182 		tmp = list_entry (l, struct dcss_segment, list);
183 		if (memcmp(tmp->dcss_name, dcss_name, 8) == 0) {
184 			retval = tmp;
185 			break;
186 		}
187 	}
188 	return retval;
189 }
190 
191 
192 /*
193  * Perform a function on a dcss segment.
194  */
195 static inline int
196 dcss_diag(int *func, void *parameter,
197            unsigned long *ret1, unsigned long *ret2)
198 {
199 	unsigned long rx, ry;
200 	int rc;
201 
202 	if (scode_set == 0) {
203 		rc = dcss_set_subcodes();
204 		if (rc < 0)
205 			return rc;
206 		scode_set = 1;
207 	}
208 	rx = (unsigned long) parameter;
209 	ry = (unsigned long) *func;
210 
211 #ifdef CONFIG_64BIT
212 	/* 64-bit Diag x'64' new subcode, keep in 64-bit addressing mode */
213 	if (*func > DCSS_SEGEXT)
214 		asm volatile(
215 			"	diag	%0,%1,0x64\n"
216 			"	ipm	%2\n"
217 			"	srl	%2,28\n"
218 			: "+d" (rx), "+d" (ry), "=d" (rc) : : "cc");
219 	/* 31-bit Diag x'64' old subcode, switch to 31-bit addressing mode */
220 	else
221 		asm volatile(
222 			"	sam31\n"
223 			"	diag	%0,%1,0x64\n"
224 			"	sam64\n"
225 			"	ipm	%2\n"
226 			"	srl	%2,28\n"
227 			: "+d" (rx), "+d" (ry), "=d" (rc) : : "cc");
228 #else
229 	asm volatile(
230 		"	diag	%0,%1,0x64\n"
231 		"	ipm	%2\n"
232 		"	srl	%2,28\n"
233 		: "+d" (rx), "+d" (ry), "=d" (rc) : : "cc");
234 #endif
235 	*ret1 = rx;
236 	*ret2 = ry;
237 	return rc;
238 }
239 
240 static inline int
241 dcss_diag_translate_rc (int vm_rc) {
242 	if (vm_rc == 44)
243 		return -ENOENT;
244 	return -EIO;
245 }
246 
247 
248 /* do a diag to get info about a segment.
249  * fills start_address, end and vm_segtype fields
250  */
251 static int
252 query_segment_type (struct dcss_segment *seg)
253 {
254 	unsigned long dummy, vmrc;
255 	int diag_cc, rc, i;
256 	struct qout64 *qout;
257 	struct qin64 *qin;
258 
259 	qin = kmalloc(sizeof(*qin), GFP_KERNEL | GFP_DMA);
260 	qout = kmalloc(sizeof(*qout), GFP_KERNEL | GFP_DMA);
261 	if ((qin == NULL) || (qout == NULL)) {
262 		rc = -ENOMEM;
263 		goto out_free;
264 	}
265 
266 	/* initialize diag input parameters */
267 	qin->qopcode = DCSS_FINDSEGA;
268 	qin->qoutptr = (unsigned long) qout;
269 	qin->qoutlen = sizeof(struct qout64);
270 	memcpy (qin->qname, seg->dcss_name, 8);
271 
272 	diag_cc = dcss_diag(&segext_scode, qin, &dummy, &vmrc);
273 
274 	if (diag_cc < 0) {
275 		rc = diag_cc;
276 		goto out_free;
277 	}
278 	if (diag_cc > 1) {
279 		pr_warning("Querying a DCSS type failed with rc=%ld\n", vmrc);
280 		rc = dcss_diag_translate_rc (vmrc);
281 		goto out_free;
282 	}
283 
284 #ifdef CONFIG_64BIT
285 	/* Only old format of output area of Diagnose x'64' is supported,
286 	   copy data for the new format. */
287 	if (segext_scode == DCSS_SEGEXT) {
288 		struct qout64_old *qout_old;
289 		qout_old = kzalloc(sizeof(*qout_old), GFP_KERNEL | GFP_DMA);
290 		if (qout_old == NULL) {
291 			rc = -ENOMEM;
292 			goto out_free;
293 		}
294 		memcpy(qout_old, qout, sizeof(struct qout64_old));
295 		qout->segstart = (unsigned long) qout_old->segstart;
296 		qout->segend = (unsigned long) qout_old->segend;
297 		qout->segcnt = qout_old->segcnt;
298 		qout->segrcnt = qout_old->segrcnt;
299 
300 		if (qout->segcnt > 6)
301 			qout->segrcnt = 6;
302 		for (i = 0; i < qout->segrcnt; i++) {
303 			qout->range[i].start =
304 				(unsigned long) qout_old->range[i].start;
305 			qout->range[i].end =
306 				(unsigned long) qout_old->range[i].end;
307 		}
308 		kfree(qout_old);
309 	}
310 #endif
311 	if (qout->segcnt > 6) {
312 		rc = -EOPNOTSUPP;
313 		goto out_free;
314 	}
315 
316 	if (qout->segcnt == 1) {
317 		seg->vm_segtype = qout->range[0].start & 0xff;
318 	} else {
319 		/* multi-part segment. only one type supported here:
320 		    - all parts are contiguous
321 		    - all parts are either EW or EN type
322 		    - maximum 6 parts allowed */
323 		unsigned long start = qout->segstart >> PAGE_SHIFT;
324 		for (i=0; i<qout->segcnt; i++) {
325 			if (((qout->range[i].start & 0xff) != SEG_TYPE_EW) &&
326 			    ((qout->range[i].start & 0xff) != SEG_TYPE_EN)) {
327 				rc = -EOPNOTSUPP;
328 				goto out_free;
329 			}
330 			if (start != qout->range[i].start >> PAGE_SHIFT) {
331 				rc = -EOPNOTSUPP;
332 				goto out_free;
333 			}
334 			start = (qout->range[i].end >> PAGE_SHIFT) + 1;
335 		}
336 		seg->vm_segtype = SEG_TYPE_EWEN;
337 	}
338 
339 	/* analyze diag output and update seg */
340 	seg->start_addr = qout->segstart;
341 	seg->end = qout->segend;
342 
343 	memcpy (seg->range, qout->range, 6*sizeof(struct qrange));
344 	seg->segcnt = qout->segcnt;
345 
346 	rc = 0;
347 
348  out_free:
349 	kfree(qin);
350 	kfree(qout);
351 	return rc;
352 }
353 
354 /*
355  * get info about a segment
356  * possible return values:
357  * -ENOSYS  : we are not running on VM
358  * -EIO     : could not perform query diagnose
359  * -ENOENT  : no such segment
360  * -EOPNOTSUPP: multi-part segment cannot be used with linux
361  * -ENOMEM  : out of memory
362  * 0 .. 6   : type of segment as defined in include/asm-s390/extmem.h
363  */
364 int
365 segment_type (char* name)
366 {
367 	int rc;
368 	struct dcss_segment seg;
369 
370 	if (!MACHINE_IS_VM)
371 		return -ENOSYS;
372 
373 	dcss_mkname(name, seg.dcss_name);
374 	rc = query_segment_type (&seg);
375 	if (rc < 0)
376 		return rc;
377 	return seg.vm_segtype;
378 }
379 
380 /*
381  * check if segment collides with other segments that are currently loaded
382  * returns 1 if this is the case, 0 if no collision was found
383  */
384 static int
385 segment_overlaps_others (struct dcss_segment *seg)
386 {
387 	struct list_head *l;
388 	struct dcss_segment *tmp;
389 
390 	BUG_ON(!mutex_is_locked(&dcss_lock));
391 	list_for_each(l, &dcss_list) {
392 		tmp = list_entry(l, struct dcss_segment, list);
393 		if ((tmp->start_addr >> 20) > (seg->end >> 20))
394 			continue;
395 		if ((tmp->end >> 20) < (seg->start_addr >> 20))
396 			continue;
397 		if (seg == tmp)
398 			continue;
399 		return 1;
400 	}
401 	return 0;
402 }
403 
404 /*
405  * real segment loading function, called from segment_load
406  */
407 static int
408 __segment_load (char *name, int do_nonshared, unsigned long *addr, unsigned long *end)
409 {
410 	unsigned long start_addr, end_addr, dummy;
411 	struct dcss_segment *seg;
412 	int rc, diag_cc;
413 
414 	start_addr = end_addr = 0;
415 	seg = kmalloc(sizeof(*seg), GFP_KERNEL | GFP_DMA);
416 	if (seg == NULL) {
417 		rc = -ENOMEM;
418 		goto out;
419 	}
420 	dcss_mkname (name, seg->dcss_name);
421 	rc = query_segment_type (seg);
422 	if (rc < 0)
423 		goto out_free;
424 
425 	if (loadshr_scode == DCSS_LOADSHRX) {
426 		if (segment_overlaps_others(seg)) {
427 			rc = -EBUSY;
428 			goto out_free;
429 		}
430 	}
431 
432 	rc = vmem_add_mapping(seg->start_addr, seg->end - seg->start_addr + 1);
433 
434 	if (rc)
435 		goto out_free;
436 
437 	seg->res = kzalloc(sizeof(struct resource), GFP_KERNEL);
438 	if (seg->res == NULL) {
439 		rc = -ENOMEM;
440 		goto out_shared;
441 	}
442 	seg->res->flags = IORESOURCE_BUSY | IORESOURCE_MEM;
443 	seg->res->start = seg->start_addr;
444 	seg->res->end = seg->end;
445 	memcpy(&seg->res_name, seg->dcss_name, 8);
446 	EBCASC(seg->res_name, 8);
447 	seg->res_name[8] = '\0';
448 	strncat(seg->res_name, " (DCSS)", 7);
449 	seg->res->name = seg->res_name;
450 	rc = seg->vm_segtype;
451 	if (rc == SEG_TYPE_SC ||
452 	    ((rc == SEG_TYPE_SR || rc == SEG_TYPE_ER) && !do_nonshared))
453 		seg->res->flags |= IORESOURCE_READONLY;
454 	if (request_resource(&iomem_resource, seg->res)) {
455 		rc = -EBUSY;
456 		kfree(seg->res);
457 		goto out_shared;
458 	}
459 
460 	if (do_nonshared)
461 		diag_cc = dcss_diag(&loadnsr_scode, seg->dcss_name,
462 				&start_addr, &end_addr);
463 	else
464 		diag_cc = dcss_diag(&loadshr_scode, seg->dcss_name,
465 				&start_addr, &end_addr);
466 	if (diag_cc < 0) {
467 		dcss_diag(&purgeseg_scode, seg->dcss_name,
468 				&dummy, &dummy);
469 		rc = diag_cc;
470 		goto out_resource;
471 	}
472 	if (diag_cc > 1) {
473 		pr_warning("Loading DCSS %s failed with rc=%ld\n", name,
474 			   end_addr);
475 		rc = dcss_diag_translate_rc(end_addr);
476 		dcss_diag(&purgeseg_scode, seg->dcss_name,
477 				&dummy, &dummy);
478 		goto out_resource;
479 	}
480 	seg->start_addr = start_addr;
481 	seg->end = end_addr;
482 	seg->do_nonshared = do_nonshared;
483 	atomic_set(&seg->ref_count, 1);
484 	list_add(&seg->list, &dcss_list);
485 	*addr = seg->start_addr;
486 	*end  = seg->end;
487 	if (do_nonshared)
488 		pr_info("DCSS %s of range %p to %p and type %s loaded as "
489 			"exclusive-writable\n", name, (void*) seg->start_addr,
490 			(void*) seg->end, segtype_string[seg->vm_segtype]);
491 	else {
492 		pr_info("DCSS %s of range %p to %p and type %s loaded in "
493 			"shared access mode\n", name, (void*) seg->start_addr,
494 			(void*) seg->end, segtype_string[seg->vm_segtype]);
495 	}
496 	goto out;
497  out_resource:
498 	release_resource(seg->res);
499 	kfree(seg->res);
500  out_shared:
501 	vmem_remove_mapping(seg->start_addr, seg->end - seg->start_addr + 1);
502  out_free:
503 	kfree(seg);
504  out:
505 	return rc;
506 }
507 
508 /*
509  * this function loads a DCSS segment
510  * name         : name of the DCSS
511  * do_nonshared : 0 indicates that the dcss should be shared with other linux images
512  *                1 indicates that the dcss should be exclusive for this linux image
513  * addr         : will be filled with start address of the segment
514  * end          : will be filled with end address of the segment
515  * return values:
516  * -ENOSYS  : we are not running on VM
517  * -EIO     : could not perform query or load diagnose
518  * -ENOENT  : no such segment
519  * -EOPNOTSUPP: multi-part segment cannot be used with linux
520  * -ENOSPC  : segment cannot be used (overlaps with storage)
521  * -EBUSY   : segment can temporarily not be used (overlaps with dcss)
522  * -ERANGE  : segment cannot be used (exceeds kernel mapping range)
523  * -EPERM   : segment is currently loaded with incompatible permissions
524  * -ENOMEM  : out of memory
525  * 0 .. 6   : type of segment as defined in include/asm-s390/extmem.h
526  */
527 int
528 segment_load (char *name, int do_nonshared, unsigned long *addr,
529 		unsigned long *end)
530 {
531 	struct dcss_segment *seg;
532 	int rc;
533 
534 	if (!MACHINE_IS_VM)
535 		return -ENOSYS;
536 
537 	mutex_lock(&dcss_lock);
538 	seg = segment_by_name (name);
539 	if (seg == NULL)
540 		rc = __segment_load (name, do_nonshared, addr, end);
541 	else {
542 		if (do_nonshared == seg->do_nonshared) {
543 			atomic_inc(&seg->ref_count);
544 			*addr = seg->start_addr;
545 			*end  = seg->end;
546 			rc    = seg->vm_segtype;
547 		} else {
548 			*addr = *end = 0;
549 			rc    = -EPERM;
550 		}
551 	}
552 	mutex_unlock(&dcss_lock);
553 	return rc;
554 }
555 
556 /*
557  * this function modifies the shared state of a DCSS segment. note that
558  * name         : name of the DCSS
559  * do_nonshared : 0 indicates that the dcss should be shared with other linux images
560  *                1 indicates that the dcss should be exclusive for this linux image
561  * return values:
562  * -EIO     : could not perform load diagnose (segment gone!)
563  * -ENOENT  : no such segment (segment gone!)
564  * -EAGAIN  : segment is in use by other exploiters, try later
565  * -EINVAL  : no segment with the given name is currently loaded - name invalid
566  * -EBUSY   : segment can temporarily not be used (overlaps with dcss)
567  * 0	    : operation succeeded
568  */
569 int
570 segment_modify_shared (char *name, int do_nonshared)
571 {
572 	struct dcss_segment *seg;
573 	unsigned long start_addr, end_addr, dummy;
574 	int rc, diag_cc;
575 
576 	start_addr = end_addr = 0;
577 	mutex_lock(&dcss_lock);
578 	seg = segment_by_name (name);
579 	if (seg == NULL) {
580 		rc = -EINVAL;
581 		goto out_unlock;
582 	}
583 	if (do_nonshared == seg->do_nonshared) {
584 		pr_info("DCSS %s is already in the requested access "
585 			"mode\n", name);
586 		rc = 0;
587 		goto out_unlock;
588 	}
589 	if (atomic_read (&seg->ref_count) != 1) {
590 		pr_warning("DCSS %s is in use and cannot be reloaded\n",
591 			   name);
592 		rc = -EAGAIN;
593 		goto out_unlock;
594 	}
595 	release_resource(seg->res);
596 	if (do_nonshared)
597 		seg->res->flags &= ~IORESOURCE_READONLY;
598 	else
599 		if (seg->vm_segtype == SEG_TYPE_SR ||
600 		    seg->vm_segtype == SEG_TYPE_ER)
601 			seg->res->flags |= IORESOURCE_READONLY;
602 
603 	if (request_resource(&iomem_resource, seg->res)) {
604 		pr_warning("DCSS %s overlaps with used memory resources "
605 			   "and cannot be reloaded\n", name);
606 		rc = -EBUSY;
607 		kfree(seg->res);
608 		goto out_del_mem;
609 	}
610 
611 	dcss_diag(&purgeseg_scode, seg->dcss_name, &dummy, &dummy);
612 	if (do_nonshared)
613 		diag_cc = dcss_diag(&loadnsr_scode, seg->dcss_name,
614 				&start_addr, &end_addr);
615 	else
616 		diag_cc = dcss_diag(&loadshr_scode, seg->dcss_name,
617 				&start_addr, &end_addr);
618 	if (diag_cc < 0) {
619 		rc = diag_cc;
620 		goto out_del_res;
621 	}
622 	if (diag_cc > 1) {
623 		pr_warning("Reloading DCSS %s failed with rc=%ld\n", name,
624 			   end_addr);
625 		rc = dcss_diag_translate_rc(end_addr);
626 		goto out_del_res;
627 	}
628 	seg->start_addr = start_addr;
629 	seg->end = end_addr;
630 	seg->do_nonshared = do_nonshared;
631 	rc = 0;
632 	goto out_unlock;
633  out_del_res:
634 	release_resource(seg->res);
635 	kfree(seg->res);
636  out_del_mem:
637 	vmem_remove_mapping(seg->start_addr, seg->end - seg->start_addr + 1);
638 	list_del(&seg->list);
639 	dcss_diag(&purgeseg_scode, seg->dcss_name, &dummy, &dummy);
640 	kfree(seg);
641  out_unlock:
642 	mutex_unlock(&dcss_lock);
643 	return rc;
644 }
645 
646 /*
647  * Decrease the use count of a DCSS segment and remove
648  * it from the address space if nobody is using it
649  * any longer.
650  */
651 void
652 segment_unload(char *name)
653 {
654 	unsigned long dummy;
655 	struct dcss_segment *seg;
656 
657 	if (!MACHINE_IS_VM)
658 		return;
659 
660 	mutex_lock(&dcss_lock);
661 	seg = segment_by_name (name);
662 	if (seg == NULL) {
663 		pr_err("Unloading unknown DCSS %s failed\n", name);
664 		goto out_unlock;
665 	}
666 	if (atomic_dec_return(&seg->ref_count) != 0)
667 		goto out_unlock;
668 	release_resource(seg->res);
669 	kfree(seg->res);
670 	vmem_remove_mapping(seg->start_addr, seg->end - seg->start_addr + 1);
671 	list_del(&seg->list);
672 	dcss_diag(&purgeseg_scode, seg->dcss_name, &dummy, &dummy);
673 	kfree(seg);
674 out_unlock:
675 	mutex_unlock(&dcss_lock);
676 }
677 
678 /*
679  * save segment content permanently
680  */
681 void
682 segment_save(char *name)
683 {
684 	struct dcss_segment *seg;
685 	char cmd1[160];
686 	char cmd2[80];
687 	int i, response;
688 
689 	if (!MACHINE_IS_VM)
690 		return;
691 
692 	mutex_lock(&dcss_lock);
693 	seg = segment_by_name (name);
694 
695 	if (seg == NULL) {
696 		pr_err("Saving unknown DCSS %s failed\n", name);
697 		goto out;
698 	}
699 
700 	sprintf(cmd1, "DEFSEG %s", name);
701 	for (i=0; i<seg->segcnt; i++) {
702 		sprintf(cmd1+strlen(cmd1), " %lX-%lX %s",
703 			seg->range[i].start >> PAGE_SHIFT,
704 			seg->range[i].end >> PAGE_SHIFT,
705 			segtype_string[seg->range[i].start & 0xff]);
706 	}
707 	sprintf(cmd2, "SAVESEG %s", name);
708 	response = 0;
709 	cpcmd(cmd1, NULL, 0, &response);
710 	if (response) {
711 		pr_err("Saving a DCSS failed with DEFSEG response code "
712 		       "%i\n", response);
713 		goto out;
714 	}
715 	cpcmd(cmd2, NULL, 0, &response);
716 	if (response) {
717 		pr_err("Saving a DCSS failed with SAVESEG response code "
718 		       "%i\n", response);
719 		goto out;
720 	}
721 out:
722 	mutex_unlock(&dcss_lock);
723 }
724 
725 /*
726  * print appropriate error message for segment_load()/segment_type()
727  * return code
728  */
729 void segment_warning(int rc, char *seg_name)
730 {
731 	switch (rc) {
732 	case -ENOENT:
733 		pr_err("DCSS %s cannot be loaded or queried\n", seg_name);
734 		break;
735 	case -ENOSYS:
736 		pr_err("DCSS %s cannot be loaded or queried without "
737 		       "z/VM\n", seg_name);
738 		break;
739 	case -EIO:
740 		pr_err("Loading or querying DCSS %s resulted in a "
741 		       "hardware error\n", seg_name);
742 		break;
743 	case -EOPNOTSUPP:
744 		pr_err("DCSS %s has multiple page ranges and cannot be "
745 		       "loaded or queried\n", seg_name);
746 		break;
747 	case -ENOSPC:
748 		pr_err("DCSS %s overlaps with used storage and cannot "
749 		       "be loaded\n", seg_name);
750 		break;
751 	case -EBUSY:
752 		pr_err("%s needs used memory resources and cannot be "
753 		       "loaded or queried\n", seg_name);
754 		break;
755 	case -EPERM:
756 		pr_err("DCSS %s is already loaded in a different access "
757 		       "mode\n", seg_name);
758 		break;
759 	case -ENOMEM:
760 		pr_err("There is not enough memory to load or query "
761 		       "DCSS %s\n", seg_name);
762 		break;
763 	case -ERANGE:
764 		pr_err("DCSS %s exceeds the kernel mapping range (%lu) "
765 		       "and cannot be loaded\n", seg_name, VMEM_MAX_PHYS);
766 		break;
767 	default:
768 		break;
769 	}
770 }
771 
772 EXPORT_SYMBOL(segment_load);
773 EXPORT_SYMBOL(segment_unload);
774 EXPORT_SYMBOL(segment_save);
775 EXPORT_SYMBOL(segment_type);
776 EXPORT_SYMBOL(segment_modify_shared);
777 EXPORT_SYMBOL(segment_warning);
778