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 #include <linux/kernel.h>
  11 #include <linux/string.h>
  12 #include <linux/spinlock.h>
  13 #include <linux/list.h>
  14 #include <linux/slab.h>
  15 #include <linux/module.h>
  16 #include <linux/bootmem.h>
  17 #include <linux/ctype.h>
  18 #include <linux/ioport.h>
  19 #include <asm/page.h>
  20 #include <asm/pgtable.h>
  21 #include <asm/ebcdic.h>
  22 #include <asm/errno.h>
  23 #include <asm/extmem.h>
  24 #include <asm/cpcmd.h>
  25 #include <asm/setup.h>
  26
  27 #define DCSS_DEBUG      /* Debug messages on/off */
  28
  29 #define DCSS_NAME "extmem"
  30 #ifdef DCSS_DEBUG
  31 #define PRINT_DEBUG(x...)       printk(KERN_DEBUG DCSS_NAME " debug:" x)
  32 #else
  33 #define PRINT_DEBUG(x...)   do {} while (0)
  34 #endif
  35 #define PRINT_INFO(x...)        printk(KERN_INFO DCSS_NAME " info:" x)
  36 #define PRINT_WARN(x...)        printk(KERN_WARNING DCSS_NAME " warning:" x)
  37 #define PRINT_ERR(x...)         printk(KERN_ERR DCSS_NAME " error:" x)
  38
  39
  40 #define DCSS_LOADSHR    0x00
  41 #define DCSS_LOADNSR    0x04
  42 #define DCSS_PURGESEG   0x08
  43 #define DCSS_FINDSEG    0x0c
  44 #define DCSS_LOADNOLY   0x10
  45 #define DCSS_SEGEXT     0x18
  46 #define DCSS_LOADSHRX   0x20
  47 #define DCSS_LOADNSRX   0x24
  48 #define DCSS_FINDSEGX   0x2c
  49 #define DCSS_SEGEXTX    0x38
  50 #define DCSS_FINDSEGA   0x0c
  51
  52 struct qrange {
  53         unsigned long  start; /* last byte type */
  54         unsigned long  end;   /* last byte reserved */
  55 };
  56
  57 struct qout64 {
  58         unsigned long segstart;
  59         unsigned long segend;
  60         int segcnt;
  61         int segrcnt;
  62         struct qrange range[6];
  63 };
  64
  65 #ifdef CONFIG_64BIT
  66 struct qrange_old {
  67         unsigned int start; /* last byte type */
  68         unsigned int end;   /* last byte reserved */
  69 };
  70
  71 /* output area format for the Diag x'64' old subcode x'18' */
  72 struct qout64_old {
  73         int segstart;
  74         int segend;
  75         int segcnt;
  76         int segrcnt;
  77         struct qrange_old range[6];
  78 };
  79 #endif
  80
  81 struct qin64 {
  82         char qopcode;
  83         char rsrv1[3];
  84         char qrcode;
  85         char rsrv2[3];
  86         char qname[8];
  87         unsigned int qoutptr;
  88         short int qoutlen;
  89 };
  90
  91 struct dcss_segment {
  92         struct list_head list;
  93         char dcss_name[8];
  94         char res_name[15];
  95         unsigned long start_addr;
  96         unsigned long end;
  97         atomic_t ref_count;
  98         int do_nonshared;
  99         unsigned int vm_segtype;
 100         struct qrange range[6];
 101         int segcnt;
 102         struct resource *res;
 103 };
 104
 105 static DEFINE_MUTEX(dcss_lock);
 106 static LIST_HEAD(dcss_list);
 107 static char *segtype_string[] = { "SW", "EW", "SR", "ER", "SN", "EN", "SC",
 108                                         "EW/EN-MIXED" };
 109 static int loadshr_scode, loadnsr_scode, findseg_scode;
 110 static int segext_scode, purgeseg_scode;
 111 static int scode_set;
 112
 113 /* set correct Diag x'64' subcodes. */
 114 static int
 115 dcss_set_subcodes(void)
 116 {
 117 #ifdef CONFIG_64BIT
 118         char *name = kmalloc(8 * sizeof(char), GFP_DMA);
 119         unsigned long rx, ry;
 120         int rc;
 121
 122         if (name == NULL)
 123                 return -ENOMEM;
 124
 125         rx = (unsigned long) name;
 126         ry = DCSS_FINDSEGX;
 127
 128         strcpy(name, "dummy");
 129         asm volatile(
 130                 "       diag    %0,%1,0x64\n"
 131                 "0:     ipm     %2\n"
 132                 "       srl     %2,28\n"
 133                 "       j       2f\n"
 134                 "1:     la      %2,3\n"
 135                 "2:\n"
 136                 EX_TABLE(0b, 1b)
 137                 : "+d" (rx), "+d" (ry), "=d" (rc) : : "cc");
 138
 139         kfree(name);
 140         /* Diag x'64' new subcodes are supported, set to new subcodes */
 141         if (rc != 3) {
 142                 loadshr_scode = DCSS_LOADSHRX;
 143                 loadnsr_scode = DCSS_LOADNSRX;
 144                 purgeseg_scode = DCSS_PURGESEG;
 145                 findseg_scode = DCSS_FINDSEGX;
 146                 segext_scode = DCSS_SEGEXTX;
 147                 return 0;
 148         }
 149 #endif
 150         /* Diag x'64' new subcodes are not supported, set to old subcodes */
 151         loadshr_scode = DCSS_LOADNOLY;
 152         loadnsr_scode = DCSS_LOADNSR;
 153         purgeseg_scode = DCSS_PURGESEG;
 154         findseg_scode = DCSS_FINDSEG;
 155         segext_scode = DCSS_SEGEXT;
 156         return 0;
 157 }
 158
 159 /*
 160  * Create the 8 bytes, ebcdic VM segment name from
 161  * an ascii name.
 162  */
 163 static void
 164 dcss_mkname(char *name, char *dcss_name)
 165 {
 166         int i;
 167
 168         for (i = 0; i < 8; i++) {
 169                 if (name[i] == '\0')
 170                         break;
 171                 dcss_name[i] = toupper(name[i]);
 172         };
 173         for (; i < 8; i++)
 174                 dcss_name[i] = ' ';
 175         ASCEBC(dcss_name, 8);
 176 }
 177
 178
 179 /*
 180  * search all segments in dcss_list, and return the one
 181  * namend *name. If not found, return NULL.
 182  */
 183 static struct dcss_segment *
 184 segment_by_name (char *name)
 185 {
 186         char dcss_name[9];
 187         struct list_head *l;
 188         struct dcss_segment *tmp, *retval = NULL;
 189
 190         BUG_ON(!mutex_is_locked(&dcss_lock));
 191         dcss_mkname (name, dcss_name);
 192         list_for_each (l, &dcss_list) {
 193                 tmp = list_entry (l, struct dcss_segment, list);
 194                 if (memcmp(tmp->dcss_name, dcss_name, 8) == 0) {
 195                         retval = tmp;
 196                         break;
 197                 }
 198         }
 199         return retval;
 200 }
 201
 202
 203 /*
 204  * Perform a function on a dcss segment.
 205  */
 206 static inline int
 207 dcss_diag(int *func, void *parameter,
 208            unsigned long *ret1, unsigned long *ret2)
 209 {
 210         unsigned long rx, ry;
 211         int rc;
 212
 213         if (scode_set == 0) {
 214                 rc = dcss_set_subcodes();
 215                 if (rc < 0)
 216                         return rc;
 217                 scode_set = 1;
 218         }
 219         rx = (unsigned long) parameter;
 220         ry = (unsigned long) *func;
 221
 222 #ifdef CONFIG_64BIT
 223         /* 64-bit Diag x'64' new subcode, keep in 64-bit addressing mode */
 224         if (*func > DCSS_SEGEXT)
 225                 asm volatile(
 226                         "       diag    %0,%1,0x64\n"
 227                         "       ipm     %2\n"
 228                         "       srl     %2,28\n"
 229                         : "+d" (rx), "+d" (ry), "=d" (rc) : : "cc");
 230         /* 31-bit Diag x'64' old subcode, switch to 31-bit addressing mode */
 231         else
 232                 asm volatile(
 233                         "       sam31\n"
 234                         "       diag    %0,%1,0x64\n"
 235                         "       sam64\n"
 236                         "       ipm     %2\n"
 237                         "       srl     %2,28\n"
 238                         : "+d" (rx), "+d" (ry), "=d" (rc) : : "cc");
 239 #else
 240         asm volatile(
 241                 "       diag    %0,%1,0x64\n"
 242                 "       ipm     %2\n"
 243                 "       srl     %2,28\n"
 244                 : "+d" (rx), "+d" (ry), "=d" (rc) : : "cc");
 245 #endif
 246         *ret1 = rx;
 247         *ret2 = ry;
 248         return rc;
 249 }
 250
 251 static inline int
 252 dcss_diag_translate_rc (int vm_rc) {
 253         if (vm_rc == 44)
 254                 return -ENOENT;
 255         return -EIO;
 256 }
 257
 258
 259 /* do a diag to get info about a segment.
 260  * fills start_address, end and vm_segtype fields
 261  */
 262 static int
 263 query_segment_type (struct dcss_segment *seg)
 264 {
 265         struct qin64  *qin = kmalloc (sizeof(struct qin64), GFP_DMA);
 266         struct qout64 *qout = kmalloc (sizeof(struct qout64), GFP_DMA);
 267
 268         int diag_cc, rc, i;
 269         unsigned long dummy, vmrc;
 270
 271         if ((qin == NULL) || (qout == NULL)) {
 272                 rc = -ENOMEM;
 273                 goto out_free;
 274         }
 275
 276         /* initialize diag input parameters */
 277         qin->qopcode = DCSS_FINDSEGA;
 278         qin->qoutptr = (unsigned long) qout;
 279         qin->qoutlen = sizeof(struct qout64);
 280         memcpy (qin->qname, seg->dcss_name, 8);
 281
 282         diag_cc = dcss_diag(&segext_scode, qin, &dummy, &vmrc);
 283
 284         if (diag_cc < 0) {
 285                 rc = diag_cc;
 286                 goto out_free;
 287         }
 288         if (diag_cc > 1) {
 289                 PRINT_WARN ("segment_type: diag returned error %ld\n", vmrc);
 290                 rc = dcss_diag_translate_rc (vmrc);
 291                 goto out_free;
 292         }
 293
 294 #ifdef CONFIG_64BIT
 295         /* Only old format of output area of Diagnose x'64' is supported,
 296            copy data for the new format. */
 297         if (segext_scode == DCSS_SEGEXT) {
 298                 struct qout64_old *qout_old;
 299                 qout_old = kzalloc(sizeof(struct qout64_old), GFP_DMA);
 300                 if (qout_old == NULL) {
 301                         rc = -ENOMEM;
 302                         goto out_free;
 303                 }
 304                 memcpy(qout_old, qout, sizeof(struct qout64_old));
 305                 qout->segstart = (unsigned long) qout_old->segstart;
 306                 qout->segend = (unsigned long) qout_old->segend;
 307                 qout->segcnt = qout_old->segcnt;
 308                 qout->segrcnt = qout_old->segrcnt;
 309
 310                 if (qout->segcnt > 6)
 311                         qout->segrcnt = 6;
 312                 for (i = 0; i < qout->segrcnt; i++) {
 313                         qout->range[i].start =
 314                                 (unsigned long) qout_old->range[i].start;
 315                         qout->range[i].end =
 316                                 (unsigned long) qout_old->range[i].end;
 317                 }
 318                 kfree(qout_old);
 319         }
 320 #endif
 321         if (qout->segcnt > 6) {
 322                 rc = -ENOTSUPP;
 323                 goto out_free;
 324         }
 325
 326         if (qout->segcnt == 1) {
 327                 seg->vm_segtype = qout->range[0].start & 0xff;
 328         } else {
 329                 /* multi-part segment. only one type supported here:
 330                     - all parts are contiguous
 331                     - all parts are either EW or EN type
 332                     - maximum 6 parts allowed */
 333                 unsigned long start = qout->segstart >> PAGE_SHIFT;
 334                 for (i=0; i<qout->segcnt; i++) {
 335                         if (((qout->range[i].start & 0xff) != SEG_TYPE_EW) &&
 336                             ((qout->range[i].start & 0xff) != SEG_TYPE_EN)) {
 337                                 rc = -ENOTSUPP;
 338                                 goto out_free;
 339                         }
 340                         if (start != qout->range[i].start >> PAGE_SHIFT) {
 341                                 rc = -ENOTSUPP;
 342                                 goto out_free;
 343                         }
 344                         start = (qout->range[i].end >> PAGE_SHIFT) + 1;
 345                 }
 346                 seg->vm_segtype = SEG_TYPE_EWEN;
 347         }
 348
 349         /* analyze diag output and update seg */
 350         seg->start_addr = qout->segstart;
 351         seg->end = qout->segend;
 352
 353         memcpy (seg->range, qout->range, 6*sizeof(struct qrange));
 354         seg->segcnt = qout->segcnt;
 355
 356         rc = 0;
 357
 358  out_free:
 359         kfree(qin);
 360         kfree(qout);
 361         return rc;
 362 }
 363
 364 /*
 365  * get info about a segment
 366  * possible return values:
 367  * -ENOSYS  : we are not running on VM
 368  * -EIO     : could not perform query diagnose
 369  * -ENOENT  : no such segment
 370  * -ENOTSUPP: multi-part segment cannot be used with linux
 371  * -ENOSPC  : segment cannot be used (overlaps with storage)
 372  * -ENOMEM  : out of memory
 373  * 0 .. 6   : type of segment as defined in include/asm-s390/extmem.h
 374  */
 375 int
 376 segment_type (char* name)
 377 {
 378         int rc;
 379         struct dcss_segment seg;
 380
 381         if (!MACHINE_IS_VM)
 382                 return -ENOSYS;
 383
 384         dcss_mkname(name, seg.dcss_name);
 385         rc = query_segment_type (&seg);
 386         if (rc < 0)
 387                 return rc;
 388         return seg.vm_segtype;
 389 }
 390
 391 /*
 392  * check if segment collides with other segments that are currently loaded
 393  * returns 1 if this is the case, 0 if no collision was found
 394  */
 395 static int
 396 segment_overlaps_others (struct dcss_segment *seg)
 397 {
 398         struct list_head *l;
 399         struct dcss_segment *tmp;
 400
 401         BUG_ON(!mutex_is_locked(&dcss_lock));
 402         list_for_each(l, &dcss_list) {
 403                 tmp = list_entry(l, struct dcss_segment, list);
 404                 if ((tmp->start_addr >> 20) > (seg->end >> 20))
 405                         continue;
 406                 if ((tmp->end >> 20) < (seg->start_addr >> 20))
 407                         continue;
 408                 if (seg == tmp)
 409                         continue;
 410                 return 1;
 411         }
 412         return 0;
 413 }
 414
 415 /*
 416  * real segment loading function, called from segment_load
 417  */
 418 static int
 419 __segment_load (char *name, int do_nonshared, unsigned long *addr, unsigned long *end)
 420 {
 421         struct dcss_segment *seg = kmalloc(sizeof(struct dcss_segment),
 422                         GFP_DMA);
 423         int rc, diag_cc;
 424         unsigned long start_addr, end_addr, dummy;
 425
 426         if (seg == NULL) {
 427                 rc = -ENOMEM;
 428                 goto out;
 429         }
 430         dcss_mkname (name, seg->dcss_name);
 431         rc = query_segment_type (seg);
 432         if (rc < 0)
 433                 goto out_free;
 434
 435         if (loadshr_scode == DCSS_LOADSHRX) {
 436                 if (segment_overlaps_others(seg)) {
 437                         rc = -EBUSY;
 438                         goto out_free;
 439                 }
 440         }
 441
 442         rc = vmem_add_mapping(seg->start_addr, seg->end - seg->start_addr + 1);
 443
 444         if (rc)
 445                 goto out_free;
 446
 447         seg->res = kzalloc(sizeof(struct resource), GFP_KERNEL);
 448         if (seg->res == NULL) {
 449                 rc = -ENOMEM;
 450                 goto out_shared;
 451         }
 452         seg->res->flags = IORESOURCE_BUSY | IORESOURCE_MEM;
 453         seg->res->start = seg->start_addr;
 454         seg->res->end = seg->end;
 455         memcpy(&seg->res_name, seg->dcss_name, 8);
 456         EBCASC(seg->res_name, 8);
 457         seg->res_name[8] = '\0';
 458         strncat(seg->res_name, " (DCSS)", 7);
 459         seg->res->name = seg->res_name;
 460         rc = seg->vm_segtype;
 461         if (rc == SEG_TYPE_SC ||
 462             ((rc == SEG_TYPE_SR || rc == SEG_TYPE_ER) && !do_nonshared))
 463                 seg->res->flags |= IORESOURCE_READONLY;
 464         if (request_resource(&iomem_resource, seg->res)) {
 465                 rc = -EBUSY;
 466                 kfree(seg->res);
 467                 goto out_shared;
 468         }
 469
 470         if (do_nonshared)
 471                 diag_cc = dcss_diag(&loadnsr_scode, seg->dcss_name,
 472                                 &start_addr, &end_addr);
 473         else
 474                 diag_cc = dcss_diag(&loadshr_scode, seg->dcss_name,
 475                                 &start_addr, &end_addr);
 476         if (diag_cc < 0) {
 477                 dcss_diag(&purgeseg_scode, seg->dcss_name,
 478                                 &dummy, &dummy);
 479                 rc = diag_cc;
 480                 goto out_resource;
 481         }
 482         if (diag_cc > 1) {
 483                 PRINT_WARN ("segment_load: could not load segment %s - "
 484                                 "diag returned error (%ld)\n",
 485                                 name, end_addr);
 486                 rc = dcss_diag_translate_rc(end_addr);
 487                 dcss_diag(&purgeseg_scode, seg->dcss_name,
 488                                 &dummy, &dummy);
 489                 goto out_resource;
 490         }
 491         seg->start_addr = start_addr;
 492         seg->end = end_addr;
 493         seg->do_nonshared = do_nonshared;
 494         atomic_set(&seg->ref_count, 1);
 495         list_add(&seg->list, &dcss_list);
 496         *addr = seg->start_addr;
 497         *end  = seg->end;
 498         if (do_nonshared)
 499                 PRINT_INFO ("segment_load: loaded segment %s range %p .. %p "
 500                                 "type %s in non-shared mode\n", name,
 501                                 (void*)seg->start_addr, (void*)seg->end,
 502                                 segtype_string[seg->vm_segtype]);
 503         else {
 504                 PRINT_INFO ("segment_load: loaded segment %s range %p .. %p "
 505                                 "type %s in shared mode\n", name,
 506                                 (void*)seg->start_addr, (void*)seg->end,
 507                                 segtype_string[seg->vm_segtype]);
 508         }
 509         goto out;
 510  out_resource:
 511         release_resource(seg->res);
 512         kfree(seg->res);
 513  out_shared:
 514         vmem_remove_mapping(seg->start_addr, seg->end - seg->start_addr + 1);
 515  out_free:
 516         kfree(seg);
 517  out:
 518         return rc;
 519 }
 520
 521 /*
 522  * this function loads a DCSS segment
 523  * name         : name of the DCSS
 524  * do_nonshared : 0 indicates that the dcss should be shared with other linux images
 525  *                1 indicates that the dcss should be exclusive for this linux image
 526  * addr         : will be filled with start address of the segment
 527  * end          : will be filled with end address of the segment
 528  * return values:
 529  * -ENOSYS  : we are not running on VM
 530  * -EIO     : could not perform query or load diagnose
 531  * -ENOENT  : no such segment
 532  * -ENOTSUPP: multi-part segment cannot be used with linux
 533  * -ENOSPC  : segment cannot be used (overlaps with storage)
 534  * -EBUSY   : segment can temporarily not be used (overlaps with dcss)
 535  * -ERANGE  : segment cannot be used (exceeds kernel mapping range)
 536  * -EPERM   : segment is currently loaded with incompatible permissions
 537  * -ENOMEM  : out of memory
 538  * 0 .. 6   : type of segment as defined in include/asm-s390/extmem.h
 539  */
 540 int
 541 segment_load (char *name, int do_nonshared, unsigned long *addr,
 542                 unsigned long *end)
 543 {
 544         struct dcss_segment *seg;
 545         int rc;
 546
 547         if (!MACHINE_IS_VM)
 548                 return -ENOSYS;
 549
 550         mutex_lock(&dcss_lock);
 551         seg = segment_by_name (name);
 552         if (seg == NULL)
 553                 rc = __segment_load (name, do_nonshared, addr, end);
 554         else {
 555                 if (do_nonshared == seg->do_nonshared) {
 556                         atomic_inc(&seg->ref_count);
 557                         *addr = seg->start_addr;
 558                         *end  = seg->end;
 559                         rc    = seg->vm_segtype;
 560                 } else {
 561                         *addr = *end = 0;
 562                         rc    = -EPERM;
 563                 }
 564         }
 565         mutex_unlock(&dcss_lock);
 566         return rc;
 567 }
 568
 569 /*
 570  * this function modifies the shared state of a DCSS segment. note that
 571  * name         : name of the DCSS
 572  * do_nonshared : 0 indicates that the dcss should be shared with other linux images
 573  *                1 indicates that the dcss should be exclusive for this linux image
 574  * return values:
 575  * -EIO     : could not perform load diagnose (segment gone!)
 576  * -ENOENT  : no such segment (segment gone!)
 577  * -EAGAIN  : segment is in use by other exploiters, try later
 578  * -EINVAL  : no segment with the given name is currently loaded - name invalid
 579  * -EBUSY   : segment can temporarily not be used (overlaps with dcss)
 580  * 0        : operation succeeded
 581  */
 582 int
 583 segment_modify_shared (char *name, int do_nonshared)
 584 {
 585         struct dcss_segment *seg;
 586         unsigned long start_addr, end_addr, dummy;
 587         int rc, diag_cc;
 588
 589         mutex_lock(&dcss_lock);
 590         seg = segment_by_name (name);
 591         if (seg == NULL) {
 592                 rc = -EINVAL;
 593                 goto out_unlock;
 594         }
 595         if (do_nonshared == seg->do_nonshared) {
 596                 PRINT_INFO ("segment_modify_shared: not reloading segment %s"
 597                                 " - already in requested mode\n",name);
 598                 rc = 0;
 599                 goto out_unlock;
 600         }
 601         if (atomic_read (&seg->ref_count) != 1) {
 602                 PRINT_WARN ("segment_modify_shared: not reloading segment %s - "
 603                                 "segment is in use by other driver(s)\n",name);
 604                 rc = -EAGAIN;
 605                 goto out_unlock;
 606         }
 607         release_resource(seg->res);
 608         if (do_nonshared)
 609                 seg->res->flags &= ~IORESOURCE_READONLY;
 610         else
 611                 if (seg->vm_segtype == SEG_TYPE_SR ||
 612                     seg->vm_segtype == SEG_TYPE_ER)
 613                         seg->res->flags |= IORESOURCE_READONLY;
 614
 615         if (request_resource(&iomem_resource, seg->res)) {
 616                 PRINT_WARN("segment_modify_shared: could not reload segment %s"
 617                            " - overlapping resources\n", name);
 618                 rc = -EBUSY;
 619                 kfree(seg->res);
 620                 goto out_del_mem;
 621         }
 622
 623         dcss_diag(&purgeseg_scode, seg->dcss_name, &dummy, &dummy);
 624         if (do_nonshared)
 625                 diag_cc = dcss_diag(&loadnsr_scode, seg->dcss_name,
 626                                 &start_addr, &end_addr);
 627         else
 628                 diag_cc = dcss_diag(&loadshr_scode, seg->dcss_name,
 629                                 &start_addr, &end_addr);
 630         if (diag_cc < 0) {
 631                 rc = diag_cc;
 632                 goto out_del_res;
 633         }
 634         if (diag_cc > 1) {
 635                 PRINT_WARN ("segment_modify_shared: could not reload segment %s"
 636                                 " - diag returned error (%ld)\n",
 637                                 name, end_addr);
 638                 rc = dcss_diag_translate_rc(end_addr);
 639                 goto out_del_res;
 640         }
 641         seg->start_addr = start_addr;
 642         seg->end = end_addr;
 643         seg->do_nonshared = do_nonshared;
 644         rc = 0;
 645         goto out_unlock;
 646  out_del_res:
 647         release_resource(seg->res);
 648         kfree(seg->res);
 649  out_del_mem:
 650         vmem_remove_mapping(seg->start_addr, seg->end - seg->start_addr + 1);
 651         list_del(&seg->list);
 652         dcss_diag(&purgeseg_scode, seg->dcss_name, &dummy, &dummy);
 653         kfree(seg);
 654  out_unlock:
 655         mutex_unlock(&dcss_lock);
 656         return rc;
 657 }
 658
 659 /*
 660  * Decrease the use count of a DCSS segment and remove
 661  * it from the address space if nobody is using it
 662  * any longer.
 663  */
 664 void
 665 segment_unload(char *name)
 666 {
 667         unsigned long dummy;
 668         struct dcss_segment *seg;
 669
 670         if (!MACHINE_IS_VM)
 671                 return;
 672
 673         mutex_lock(&dcss_lock);
 674         seg = segment_by_name (name);
 675         if (seg == NULL) {
 676                 PRINT_ERR ("could not find segment %s in segment_unload, "
 677                                 "please report to linux390@de.ibm.com\n",name);
 678                 goto out_unlock;
 679         }
 680         if (atomic_dec_return(&seg->ref_count) != 0)
 681                 goto out_unlock;
 682         release_resource(seg->res);
 683         kfree(seg->res);
 684         vmem_remove_mapping(seg->start_addr, seg->end - seg->start_addr + 1);
 685         list_del(&seg->list);
 686         dcss_diag(&purgeseg_scode, seg->dcss_name, &dummy, &dummy);
 687         kfree(seg);
 688 out_unlock:
 689         mutex_unlock(&dcss_lock);
 690 }
 691
 692 /*
 693  * save segment content permanently
 694  */
 695 void
 696 segment_save(char *name)
 697 {
 698         struct dcss_segment *seg;
 699         int startpfn = 0;
 700         int endpfn = 0;
 701         char cmd1[160];
 702         char cmd2[80];
 703         int i, response;
 704
 705         if (!MACHINE_IS_VM)
 706                 return;
 707
 708         mutex_lock(&dcss_lock);
 709         seg = segment_by_name (name);
 710
 711         if (seg == NULL) {
 712                 PRINT_ERR("could not find segment %s in segment_save, please "
 713                           "report to linux390@de.ibm.com\n", name);
 714                 goto out;
 715         }
 716
 717         startpfn = seg->start_addr >> PAGE_SHIFT;
 718         endpfn = (seg->end) >> PAGE_SHIFT;
 719         sprintf(cmd1, "DEFSEG %s", name);
 720         for (i=0; i<seg->segcnt; i++) {
 721                 sprintf(cmd1+strlen(cmd1), " %lX-%lX %s",
 722                         seg->range[i].start >> PAGE_SHIFT,
 723                         seg->range[i].end >> PAGE_SHIFT,
 724                         segtype_string[seg->range[i].start & 0xff]);
 725         }
 726         sprintf(cmd2, "SAVESEG %s", name);
 727         response = 0;
 728         cpcmd(cmd1, NULL, 0, &response);
 729         if (response) {
 730                 PRINT_ERR("segment_save: DEFSEG failed with response code %i\n",
 731                           response);
 732                 goto out;
 733         }
 734         cpcmd(cmd2, NULL, 0, &response);
 735         if (response) {
 736                 PRINT_ERR("segment_save: SAVESEG failed with response code %i\n",
 737                           response);
 738                 goto out;
 739         }
 740 out:
 741         mutex_unlock(&dcss_lock);
 742 }
 743
 744 /*
 745  * print appropriate error message for segment_load()/segment_type()
 746  * return code
 747  */
 748 void segment_warning(int rc, char *seg_name)
 749 {
 750         switch (rc) {
 751         case -ENOENT:
 752                 PRINT_WARN("cannot load/query segment %s, "
 753                            "does not exist\n", seg_name);
 754                 break;
 755         case -ENOSYS:
 756                 PRINT_WARN("cannot load/query segment %s, "
 757                            "not running on VM\n", seg_name);
 758                 break;
 759         case -EIO:
 760                 PRINT_WARN("cannot load/query segment %s, "
 761                            "hardware error\n", seg_name);
 762                 break;
 763         case -ENOTSUPP:
 764                 PRINT_WARN("cannot load/query segment %s, "
 765                            "is a multi-part segment\n", seg_name);
 766                 break;
 767         case -ENOSPC:
 768                 PRINT_WARN("cannot load/query segment %s, "
 769                            "overlaps with storage\n", seg_name);
 770                 break;
 771         case -EBUSY:
 772                 PRINT_WARN("cannot load/query segment %s, "
 773                            "overlaps with already loaded dcss\n", seg_name);
 774                 break;
 775         case -EPERM:
 776                 PRINT_WARN("cannot load/query segment %s, "
 777                            "already loaded in incompatible mode\n", seg_name);
 778                 break;
 779         case -ENOMEM:
 780                 PRINT_WARN("cannot load/query segment %s, "
 781                            "out of memory\n", seg_name);
 782                 break;
 783         case -ERANGE:
 784                 PRINT_WARN("cannot load/query segment %s, "
 785                            "exceeds kernel mapping range\n", seg_name);
 786                 break;
 787         default:
 788                 PRINT_WARN("cannot load/query segment %s, "
 789                            "return value %i\n", seg_name, rc);
 790                 break;
 791         }
 792 }
 793
 794 EXPORT_SYMBOL(segment_load);
 795 EXPORT_SYMBOL(segment_unload);
 796 EXPORT_SYMBOL(segment_save);
 797 EXPORT_SYMBOL(segment_type);
 798 EXPORT_SYMBOL(segment_modify_shared);
 799 EXPORT_SYMBOL(segment_warning);