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_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         struct qin64  *qin = kmalloc (sizeof(struct qin64), GFP_DMA);
 256         struct qout64 *qout = kmalloc (sizeof(struct qout64), GFP_DMA);
 257
 258         int diag_cc, rc, i;
 259         unsigned long dummy, vmrc;
 260
 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(struct qout64_old), 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 = -ENOTSUPP;
 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 = -ENOTSUPP;
 328                                 goto out_free;
 329                         }
 330                         if (start != qout->range[i].start >> PAGE_SHIFT) {
 331                                 rc = -ENOTSUPP;
 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  * -ENOTSUPP: 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         struct dcss_segment *seg = kmalloc(sizeof(struct dcss_segment),
 411                         GFP_DMA);
 412         int rc, diag_cc;
 413         unsigned long start_addr, end_addr, dummy;
 414
 415         if (seg == NULL) {
 416                 rc = -ENOMEM;
 417                 goto out;
 418         }
 419         dcss_mkname (name, seg->dcss_name);
 420         rc = query_segment_type (seg);
 421         if (rc < 0)
 422                 goto out_free;
 423
 424         if (loadshr_scode == DCSS_LOADSHRX) {
 425                 if (segment_overlaps_others(seg)) {
 426                         rc = -EBUSY;
 427                         goto out_free;
 428                 }
 429         }
 430
 431         rc = vmem_add_mapping(seg->start_addr, seg->end - seg->start_addr + 1);
 432
 433         if (rc)
 434                 goto out_free;
 435
 436         seg->res = kzalloc(sizeof(struct resource), GFP_KERNEL);
 437         if (seg->res == NULL) {
 438                 rc = -ENOMEM;
 439                 goto out_shared;
 440         }
 441         seg->res->flags = IORESOURCE_BUSY | IORESOURCE_MEM;
 442         seg->res->start = seg->start_addr;
 443         seg->res->end = seg->end;
 444         memcpy(&seg->res_name, seg->dcss_name, 8);
 445         EBCASC(seg->res_name, 8);
 446         seg->res_name[8] = '\0';
 447         strncat(seg->res_name, " (DCSS)", 7);
 448         seg->res->name = seg->res_name;
 449         rc = seg->vm_segtype;
 450         if (rc == SEG_TYPE_SC ||
 451             ((rc == SEG_TYPE_SR || rc == SEG_TYPE_ER) && !do_nonshared))
 452                 seg->res->flags |= IORESOURCE_READONLY;
 453         if (request_resource(&iomem_resource, seg->res)) {
 454                 rc = -EBUSY;
 455                 kfree(seg->res);
 456                 goto out_shared;
 457         }
 458
 459         if (do_nonshared)
 460                 diag_cc = dcss_diag(&loadnsr_scode, seg->dcss_name,
 461                                 &start_addr, &end_addr);
 462         else
 463                 diag_cc = dcss_diag(&loadshr_scode, seg->dcss_name,
 464                                 &start_addr, &end_addr);
 465         if (diag_cc < 0) {
 466                 dcss_diag(&purgeseg_scode, seg->dcss_name,
 467                                 &dummy, &dummy);
 468                 rc = diag_cc;
 469                 goto out_resource;
 470         }
 471         if (diag_cc > 1) {
 472                 pr_warning("Loading DCSS %s failed with rc=%ld\n", name,
 473                            end_addr);
 474                 rc = dcss_diag_translate_rc(end_addr);
 475                 dcss_diag(&purgeseg_scode, seg->dcss_name,
 476                                 &dummy, &dummy);
 477                 goto out_resource;
 478         }
 479         seg->start_addr = start_addr;
 480         seg->end = end_addr;
 481         seg->do_nonshared = do_nonshared;
 482         atomic_set(&seg->ref_count, 1);
 483         list_add(&seg->list, &dcss_list);
 484         *addr = seg->start_addr;
 485         *end  = seg->end;
 486         if (do_nonshared)
 487                 pr_info("DCSS %s of range %p to %p and type %s loaded as "
 488                         "exclusive-writable\n", name, (void*) seg->start_addr,
 489                         (void*) seg->end, segtype_string[seg->vm_segtype]);
 490         else {
 491                 pr_info("DCSS %s of range %p to %p and type %s loaded in "
 492                         "shared access mode\n", name, (void*) seg->start_addr,
 493                         (void*) seg->end, segtype_string[seg->vm_segtype]);
 494         }
 495         goto out;
 496  out_resource:
 497         release_resource(seg->res);
 498         kfree(seg->res);
 499  out_shared:
 500         vmem_remove_mapping(seg->start_addr, seg->end - seg->start_addr + 1);
 501  out_free:
 502         kfree(seg);
 503  out:
 504         return rc;
 505 }
 506
 507 /*
 508  * this function loads a DCSS segment
 509  * name         : name of the DCSS
 510  * do_nonshared : 0 indicates that the dcss should be shared with other linux images
 511  *                1 indicates that the dcss should be exclusive for this linux image
 512  * addr         : will be filled with start address of the segment
 513  * end          : will be filled with end address of the segment
 514  * return values:
 515  * -ENOSYS  : we are not running on VM
 516  * -EIO     : could not perform query or load diagnose
 517  * -ENOENT  : no such segment
 518  * -ENOTSUPP: multi-part segment cannot be used with linux
 519  * -ENOSPC  : segment cannot be used (overlaps with storage)
 520  * -EBUSY   : segment can temporarily not be used (overlaps with dcss)
 521  * -ERANGE  : segment cannot be used (exceeds kernel mapping range)
 522  * -EPERM   : segment is currently loaded with incompatible permissions
 523  * -ENOMEM  : out of memory
 524  * 0 .. 6   : type of segment as defined in include/asm-s390/extmem.h
 525  */
 526 int
 527 segment_load (char *name, int do_nonshared, unsigned long *addr,
 528                 unsigned long *end)
 529 {
 530         struct dcss_segment *seg;
 531         int rc;
 532
 533         if (!MACHINE_IS_VM)
 534                 return -ENOSYS;
 535
 536         mutex_lock(&dcss_lock);
 537         seg = segment_by_name (name);
 538         if (seg == NULL)
 539                 rc = __segment_load (name, do_nonshared, addr, end);
 540         else {
 541                 if (do_nonshared == seg->do_nonshared) {
 542                         atomic_inc(&seg->ref_count);
 543                         *addr = seg->start_addr;
 544                         *end  = seg->end;
 545                         rc    = seg->vm_segtype;
 546                 } else {
 547                         *addr = *end = 0;
 548                         rc    = -EPERM;
 549                 }
 550         }
 551         mutex_unlock(&dcss_lock);
 552         return rc;
 553 }
 554
 555 /*
 556  * this function modifies the shared state of a DCSS segment. note that
 557  * name         : name of the DCSS
 558  * do_nonshared : 0 indicates that the dcss should be shared with other linux images
 559  *                1 indicates that the dcss should be exclusive for this linux image
 560  * return values:
 561  * -EIO     : could not perform load diagnose (segment gone!)
 562  * -ENOENT  : no such segment (segment gone!)
 563  * -EAGAIN  : segment is in use by other exploiters, try later
 564  * -EINVAL  : no segment with the given name is currently loaded - name invalid
 565  * -EBUSY   : segment can temporarily not be used (overlaps with dcss)
 566  * 0        : operation succeeded
 567  */
 568 int
 569 segment_modify_shared (char *name, int do_nonshared)
 570 {
 571         struct dcss_segment *seg;
 572         unsigned long start_addr, end_addr, dummy;
 573         int rc, diag_cc;
 574
 575         mutex_lock(&dcss_lock);
 576         seg = segment_by_name (name);
 577         if (seg == NULL) {
 578                 rc = -EINVAL;
 579                 goto out_unlock;
 580         }
 581         if (do_nonshared == seg->do_nonshared) {
 582                 pr_info("DCSS %s is already in the requested access "
 583                         "mode\n", name);
 584                 rc = 0;
 585                 goto out_unlock;
 586         }
 587         if (atomic_read (&seg->ref_count) != 1) {
 588                 pr_warning("DCSS %s is in use and cannot be reloaded\n",
 589                            name);
 590                 rc = -EAGAIN;
 591                 goto out_unlock;
 592         }
 593         release_resource(seg->res);
 594         if (do_nonshared)
 595                 seg->res->flags &= ~IORESOURCE_READONLY;
 596         else
 597                 if (seg->vm_segtype == SEG_TYPE_SR ||
 598                     seg->vm_segtype == SEG_TYPE_ER)
 599                         seg->res->flags |= IORESOURCE_READONLY;
 600
 601         if (request_resource(&iomem_resource, seg->res)) {
 602                 pr_warning("DCSS %s overlaps with used memory resources "
 603                            "and cannot be reloaded\n", name);
 604                 rc = -EBUSY;
 605                 kfree(seg->res);
 606                 goto out_del_mem;
 607         }
 608
 609         dcss_diag(&purgeseg_scode, seg->dcss_name, &dummy, &dummy);
 610         if (do_nonshared)
 611                 diag_cc = dcss_diag(&loadnsr_scode, seg->dcss_name,
 612                                 &start_addr, &end_addr);
 613         else
 614                 diag_cc = dcss_diag(&loadshr_scode, seg->dcss_name,
 615                                 &start_addr, &end_addr);
 616         if (diag_cc < 0) {
 617                 rc = diag_cc;
 618                 goto out_del_res;
 619         }
 620         if (diag_cc > 1) {
 621                 pr_warning("Reloading DCSS %s failed with rc=%ld\n", name,
 622                            end_addr);
 623                 rc = dcss_diag_translate_rc(end_addr);
 624                 goto out_del_res;
 625         }
 626         seg->start_addr = start_addr;
 627         seg->end = end_addr;
 628         seg->do_nonshared = do_nonshared;
 629         rc = 0;
 630         goto out_unlock;
 631  out_del_res:
 632         release_resource(seg->res);
 633         kfree(seg->res);
 634  out_del_mem:
 635         vmem_remove_mapping(seg->start_addr, seg->end - seg->start_addr + 1);
 636         list_del(&seg->list);
 637         dcss_diag(&purgeseg_scode, seg->dcss_name, &dummy, &dummy);
 638         kfree(seg);
 639  out_unlock:
 640         mutex_unlock(&dcss_lock);
 641         return rc;
 642 }
 643
 644 /*
 645  * Decrease the use count of a DCSS segment and remove
 646  * it from the address space if nobody is using it
 647  * any longer.
 648  */
 649 void
 650 segment_unload(char *name)
 651 {
 652         unsigned long dummy;
 653         struct dcss_segment *seg;
 654
 655         if (!MACHINE_IS_VM)
 656                 return;
 657
 658         mutex_lock(&dcss_lock);
 659         seg = segment_by_name (name);
 660         if (seg == NULL) {
 661                 pr_err("Unloading unknown DCSS %s failed\n", name);
 662                 goto out_unlock;
 663         }
 664         if (atomic_dec_return(&seg->ref_count) != 0)
 665                 goto out_unlock;
 666         release_resource(seg->res);
 667         kfree(seg->res);
 668         vmem_remove_mapping(seg->start_addr, seg->end - seg->start_addr + 1);
 669         list_del(&seg->list);
 670         dcss_diag(&purgeseg_scode, seg->dcss_name, &dummy, &dummy);
 671         kfree(seg);
 672 out_unlock:
 673         mutex_unlock(&dcss_lock);
 674 }
 675
 676 /*
 677  * save segment content permanently
 678  */
 679 void
 680 segment_save(char *name)
 681 {
 682         struct dcss_segment *seg;
 683         int startpfn = 0;
 684         int endpfn = 0;
 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         startpfn = seg->start_addr >> PAGE_SHIFT;
 701         endpfn = (seg->end) >> PAGE_SHIFT;
 702         sprintf(cmd1, "DEFSEG %s", name);
 703         for (i=0; i<seg->segcnt; i++) {
 704                 sprintf(cmd1+strlen(cmd1), " %lX-%lX %s",
 705                         seg->range[i].start >> PAGE_SHIFT,
 706                         seg->range[i].end >> PAGE_SHIFT,
 707                         segtype_string[seg->range[i].start & 0xff]);
 708         }
 709         sprintf(cmd2, "SAVESEG %s", name);
 710         response = 0;
 711         cpcmd(cmd1, NULL, 0, &response);
 712         if (response) {
 713                 pr_err("Saving a DCSS failed with DEFSEG response code "
 714                        "%i\n", response);
 715                 goto out;
 716         }
 717         cpcmd(cmd2, NULL, 0, &response);
 718         if (response) {
 719                 pr_err("Saving a DCSS failed with SAVESEG response code "
 720                        "%i\n", response);
 721                 goto out;
 722         }
 723 out:
 724         mutex_unlock(&dcss_lock);
 725 }
 726
 727 /*
 728  * print appropriate error message for segment_load()/segment_type()
 729  * return code
 730  */
 731 void segment_warning(int rc, char *seg_name)
 732 {
 733         switch (rc) {
 734         case -ENOENT:
 735                 pr_err("DCSS %s cannot be loaded or queried\n", seg_name);
 736                 break;
 737         case -ENOSYS:
 738                 pr_err("DCSS %s cannot be loaded or queried without "
 739                        "z/VM\n", seg_name);
 740                 break;
 741         case -EIO:
 742                 pr_err("Loading or querying DCSS %s resulted in a "
 743                        "hardware error\n", seg_name);
 744                 break;
 745         case -ENOTSUPP:
 746                 pr_err("DCSS %s has multiple page ranges and cannot be "
 747                        "loaded or queried\n", seg_name);
 748                 break;
 749         case -ENOSPC:
 750                 pr_err("DCSS %s overlaps with used storage and cannot "
 751                        "be loaded\n", seg_name);
 752                 break;
 753         case -EBUSY:
 754                 pr_err("%s needs used memory resources and cannot be "
 755                        "loaded or queried\n", seg_name);
 756                 break;
 757         case -EPERM:
 758                 pr_err("DCSS %s is already loaded in a different access "
 759                        "mode\n", seg_name);
 760                 break;
 761         case -ENOMEM:
 762                 pr_err("There is not enough memory to load or query "
 763                        "DCSS %s\n", seg_name);
 764                 break;
 765         case -ERANGE:
 766                 pr_err("DCSS %s exceeds the kernel mapping range (%lu) "
 767                        "and cannot be loaded\n", seg_name, VMEM_MAX_PHYS);
 768                 break;
 769         default:
 770                 break;
 771         }
 772 }
 773
 774 EXPORT_SYMBOL(segment_load);
 775 EXPORT_SYMBOL(segment_unload);
 776 EXPORT_SYMBOL(segment_save);
 777 EXPORT_SYMBOL(segment_type);
 778 EXPORT_SYMBOL(segment_modify_shared);
 779 EXPORT_SYMBOL(segment_warning);