arch/s390/mm/extmem.c

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