arch/x86/kernel/e820_64.c

   1 /*
   2  * Handle the memory map.
   3  * The functions here do the job until bootmem takes over.
   4  *
   5  *  Getting sanitize_e820_map() in sync with i386 version by applying change:
   6  *  -  Provisions for empty E820 memory regions (reported by certain BIOSes).
   7  *     Alex Achenbach <xela@slit.de>, December 2002.
   8  *  Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
   9  *
  10  */
  11 #include <linux/kernel.h>
  12 #include <linux/types.h>
  13 #include <linux/init.h>
  14 #include <linux/bootmem.h>
  15 #include <linux/ioport.h>
  16 #include <linux/string.h>
  17 #include <linux/kexec.h>
  18 #include <linux/module.h>
  19 #include <linux/mm.h>
  20 #include <linux/suspend.h>
  21 #include <linux/pfn.h>
  22
  23 #include <asm/pgtable.h>
  24 #include <asm/page.h>
  25 #include <asm/e820.h>
  26 #include <asm/proto.h>
  27 #include <asm/setup.h>
  28 #include <asm/sections.h>
  29 #include <asm/kdebug.h>
  30
  31 struct e820map e820;
  32
  33 /*
  34  * PFN of last memory page.
  35  */
  36 unsigned long end_pfn;
  37
  38 /*
  39  * end_pfn only includes RAM, while end_pfn_map includes all e820 entries.
  40  * The direct mapping extends to end_pfn_map, so that we can directly access
  41  * apertures, ACPI and other tables without having to play with fixmaps.
  42  */
  43 unsigned long end_pfn_map;
  44
  45 /*
  46  * Last pfn which the user wants to use.
  47  */
  48 static unsigned long __initdata end_user_pfn = MAXMEM>>PAGE_SHIFT;
  49
  50 extern struct resource code_resource, data_resource, bss_resource;
  51
  52 /* Check for some hardcoded bad areas that early boot is not allowed to touch */
  53 static inline int bad_addr(unsigned long *addrp, unsigned long size)
  54 {
  55         unsigned long addr = *addrp, last = addr + size;
  56
  57         /* various gunk below that needed for SMP startup */
  58         if (addr < 0x8000) {
  59                 *addrp = PAGE_ALIGN(0x8000);
  60                 return 1;
  61         }
  62
  63         /* direct mapping tables of the kernel */
  64         if (last >= table_start<<PAGE_SHIFT && addr < table_end<<PAGE_SHIFT) {
  65                 *addrp = PAGE_ALIGN(table_end << PAGE_SHIFT);
  66                 return 1;
  67         }
  68
  69         /* initrd */
  70 #ifdef CONFIG_BLK_DEV_INITRD
  71         if (boot_params.hdr.type_of_loader && boot_params.hdr.ramdisk_image) {
  72                 unsigned long ramdisk_image = boot_params.hdr.ramdisk_image;
  73                 unsigned long ramdisk_size  = boot_params.hdr.ramdisk_size;
  74                 unsigned long ramdisk_end   = ramdisk_image+ramdisk_size;
  75
  76                 if (last >= ramdisk_image && addr < ramdisk_end) {
  77                         *addrp = PAGE_ALIGN(ramdisk_end);
  78                         return 1;
  79                 }
  80         }
  81 #endif
  82         /* kernel code */
  83         if (last >= __pa_symbol(&_text) && addr < __pa_symbol(&_end)) {
  84                 *addrp = PAGE_ALIGN(__pa_symbol(&_end));
  85                 return 1;
  86         }
  87
  88         if (last >= ebda_addr && addr < ebda_addr + ebda_size) {
  89                 *addrp = PAGE_ALIGN(ebda_addr + ebda_size);
  90                 return 1;
  91         }
  92
  93 #ifdef CONFIG_NUMA
  94         /* NUMA memory to node map */
  95         if (last >= nodemap_addr && addr < nodemap_addr + nodemap_size) {
  96                 *addrp = nodemap_addr + nodemap_size;
  97                 return 1;
  98         }
  99 #endif
 100         /* XXX ramdisk image here? */
 101         return 0;
 102 }
 103
 104 /*
 105  * This function checks if any part of the range <start,end> is mapped
 106  * with type.
 107  */
 108 int
 109 e820_any_mapped(unsigned long start, unsigned long end, unsigned type)
 110 {
 111         int i;
 112
 113         for (i = 0; i < e820.nr_map; i++) {
 114                 struct e820entry *ei = &e820.map[i];
 115
 116                 if (type && ei->type != type)
 117                         continue;
 118                 if (ei->addr >= end || ei->addr + ei->size <= start)
 119                         continue;
 120                 return 1;
 121         }
 122         return 0;
 123 }
 124 EXPORT_SYMBOL_GPL(e820_any_mapped);
 125
 126 /*
 127  * This function checks if the entire range <start,end> is mapped with type.
 128  *
 129  * Note: this function only works correct if the e820 table is sorted and
 130  * not-overlapping, which is the case
 131  */
 132 int __init e820_all_mapped(unsigned long start, unsigned long end,
 133                            unsigned type)
 134 {
 135         int i;
 136
 137         for (i = 0; i < e820.nr_map; i++) {
 138                 struct e820entry *ei = &e820.map[i];
 139
 140                 if (type && ei->type != type)
 141                         continue;
 142                 /* is the region (part) in overlap with the current region ?*/
 143                 if (ei->addr >= end || ei->addr + ei->size <= start)
 144                         continue;
 145
 146                 /* if the region is at the beginning of <start,end> we move
 147                  * start to the end of the region since it's ok until there
 148                  */
 149                 if (ei->addr <= start)
 150                         start = ei->addr + ei->size;
 151                 /*
 152                  * if start is now at or beyond end, we're done, full
 153                  * coverage
 154                  */
 155                 if (start >= end)
 156                         return 1;
 157         }
 158         return 0;
 159 }
 160
 161 /*
 162  * Find a free area in a specific range.
 163  */
 164 unsigned long __init find_e820_area(unsigned long start, unsigned long end,
 165                                     unsigned size)
 166 {
 167         int i;
 168
 169         for (i = 0; i < e820.nr_map; i++) {
 170                 struct e820entry *ei = &e820.map[i];
 171                 unsigned long addr = ei->addr, last;
 172
 173                 if (ei->type != E820_RAM)
 174                         continue;
 175                 if (addr < start)
 176                         addr = start;
 177                 if (addr > ei->addr + ei->size)
 178                         continue;
 179                 while (bad_addr(&addr, size) && addr+size <= ei->addr+ei->size)
 180                         ;
 181                 last = PAGE_ALIGN(addr) + size;
 182                 if (last > ei->addr + ei->size)
 183                         continue;
 184                 if (last > end)
 185                         continue;
 186                 return addr;
 187         }
 188         return -1UL;
 189 }
 190
 191 /*
 192  * Find the highest page frame number we have available
 193  */
 194 unsigned long __init e820_end_of_ram(void)
 195 {
 196         unsigned long end_pfn;
 197
 198         end_pfn = find_max_pfn_with_active_regions();
 199
 200         if (end_pfn > end_pfn_map)
 201                 end_pfn_map = end_pfn;
 202         if (end_pfn_map > MAXMEM>>PAGE_SHIFT)
 203                 end_pfn_map = MAXMEM>>PAGE_SHIFT;
 204         if (end_pfn > end_user_pfn)
 205                 end_pfn = end_user_pfn;
 206         if (end_pfn > end_pfn_map)
 207                 end_pfn = end_pfn_map;
 208
 209         printk(KERN_INFO "end_pfn_map = %lu\n", end_pfn_map);
 210         return end_pfn;
 211 }
 212
 213 /*
 214  * Mark e820 reserved areas as busy for the resource manager.
 215  */
 216 void __init e820_reserve_resources(void)
 217 {
 218         int i;
 219         for (i = 0; i < e820.nr_map; i++) {
 220                 struct resource *res;
 221                 res = alloc_bootmem_low(sizeof(struct resource));
 222                 switch (e820.map[i].type) {
 223                 case E820_RAM:  res->name = "System RAM"; break;
 224                 case E820_ACPI: res->name = "ACPI Tables"; break;
 225                 case E820_NVS:  res->name = "ACPI Non-volatile Storage"; break;
 226                 default:        res->name = "reserved";
 227                 }
 228                 res->start = e820.map[i].addr;
 229                 res->end = res->start + e820.map[i].size - 1;
 230                 res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
 231                 request_resource(&iomem_resource, res);
 232                 if (e820.map[i].type == E820_RAM) {
 233                         /*
 234                          * We don't know which RAM region contains kernel data,
 235                          * so we try it repeatedly and let the resource manager
 236                          * test it.
 237                          */
 238                         request_resource(res, &code_resource);
 239                         request_resource(res, &data_resource);
 240                         request_resource(res, &bss_resource);
 241 #ifdef CONFIG_KEXEC
 242                         if (crashk_res.start != crashk_res.end)
 243                                 request_resource(res, &crashk_res);
 244 #endif
 245                 }
 246         }
 247 }
 248
 249 /*
 250  * Find the ranges of physical addresses that do not correspond to
 251  * e820 RAM areas and mark the corresponding pages as nosave for software
 252  * suspend and suspend to RAM.
 253  *
 254  * This function requires the e820 map to be sorted and without any
 255  * overlapping entries and assumes the first e820 area to be RAM.
 256  */
 257 void __init e820_mark_nosave_regions(void)
 258 {
 259         int i;
 260         unsigned long paddr;
 261
 262         paddr = round_down(e820.map[0].addr + e820.map[0].size, PAGE_SIZE);
 263         for (i = 1; i < e820.nr_map; i++) {
 264                 struct e820entry *ei = &e820.map[i];
 265
 266                 if (paddr < ei->addr)
 267                         register_nosave_region(PFN_DOWN(paddr),
 268                                                 PFN_UP(ei->addr));
 269
 270                 paddr = round_down(ei->addr + ei->size, PAGE_SIZE);
 271                 if (ei->type != E820_RAM)
 272                         register_nosave_region(PFN_UP(ei->addr),
 273                                                 PFN_DOWN(paddr));
 274
 275                 if (paddr >= (end_pfn << PAGE_SHIFT))
 276                         break;
 277         }
 278 }
 279
 280 /*
 281  * Finds an active region in the address range from start_pfn to end_pfn and
 282  * returns its range in ei_startpfn and ei_endpfn for the e820 entry.
 283  */
 284 static int __init e820_find_active_region(const struct e820entry *ei,
 285                                           unsigned long start_pfn,
 286                                           unsigned long end_pfn,
 287                                           unsigned long *ei_startpfn,
 288                                           unsigned long *ei_endpfn)
 289 {
 290         *ei_startpfn = round_up(ei->addr, PAGE_SIZE) >> PAGE_SHIFT;
 291         *ei_endpfn = round_down(ei->addr + ei->size, PAGE_SIZE) >> PAGE_SHIFT;
 292
 293         /* Skip map entries smaller than a page */
 294         if (*ei_startpfn >= *ei_endpfn)
 295                 return 0;
 296
 297         /* Check if end_pfn_map should be updated */
 298         if (ei->type != E820_RAM && *ei_endpfn > end_pfn_map)
 299                 end_pfn_map = *ei_endpfn;
 300
 301         /* Skip if map is outside the node */
 302         if (ei->type != E820_RAM || *ei_endpfn <= start_pfn ||
 303                                     *ei_startpfn >= end_pfn)
 304                 return 0;
 305
 306         /* Check for overlaps */
 307         if (*ei_startpfn < start_pfn)
 308                 *ei_startpfn = start_pfn;
 309         if (*ei_endpfn > end_pfn)
 310                 *ei_endpfn = end_pfn;
 311
 312         /* Obey end_user_pfn to save on memmap */
 313         if (*ei_startpfn >= end_user_pfn)
 314                 return 0;
 315         if (*ei_endpfn > end_user_pfn)
 316                 *ei_endpfn = end_user_pfn;
 317
 318         return 1;
 319 }
 320
 321 /* Walk the e820 map and register active regions within a node */
 322 void __init
 323 e820_register_active_regions(int nid, unsigned long start_pfn,
 324                                                         unsigned long end_pfn)
 325 {
 326         unsigned long ei_startpfn;
 327         unsigned long ei_endpfn;
 328         int i;
 329
 330         for (i = 0; i < e820.nr_map; i++)
 331                 if (e820_find_active_region(&e820.map[i],
 332                                             start_pfn, end_pfn,
 333                                             &ei_startpfn, &ei_endpfn))
 334                         add_active_range(nid, ei_startpfn, ei_endpfn);
 335 }
 336
 337 /*
 338  * Add a memory region to the kernel e820 map.
 339  */
 340 void __init add_memory_region(unsigned long start, unsigned long size, int type)
 341 {
 342         int x = e820.nr_map;
 343
 344         if (x == E820MAX) {
 345                 printk(KERN_ERR "Ooops! Too many entries in the memory map!\n");
 346                 return;
 347         }
 348
 349         e820.map[x].addr = start;
 350         e820.map[x].size = size;
 351         e820.map[x].type = type;
 352         e820.nr_map++;
 353 }
 354
 355 /*
 356  * Find the hole size (in bytes) in the memory range.
 357  * @start: starting address of the memory range to scan
 358  * @end: ending address of the memory range to scan
 359  */
 360 unsigned long __init e820_hole_size(unsigned long start, unsigned long end)
 361 {
 362         unsigned long start_pfn = start >> PAGE_SHIFT;
 363         unsigned long end_pfn = end >> PAGE_SHIFT;
 364         unsigned long ei_startpfn, ei_endpfn, ram = 0;
 365         int i;
 366
 367         for (i = 0; i < e820.nr_map; i++) {
 368                 if (e820_find_active_region(&e820.map[i],
 369                                             start_pfn, end_pfn,
 370                                             &ei_startpfn, &ei_endpfn))
 371                         ram += ei_endpfn - ei_startpfn;
 372         }
 373         return end - start - (ram << PAGE_SHIFT);
 374 }
 375
 376 void __init e820_print_map(char *who)
 377 {
 378         int i;
 379
 380         for (i = 0; i < e820.nr_map; i++) {
 381                 printk(KERN_INFO " %s: %016Lx - %016Lx ", who,
 382                        (unsigned long long) e820.map[i].addr,
 383                        (unsigned long long)
 384                        (e820.map[i].addr + e820.map[i].size));
 385                 switch (e820.map[i].type) {
 386                 case E820_RAM:
 387                         printk(KERN_CONT "(usable)\n");
 388                         break;
 389                 case E820_RESERVED:
 390                         printk(KERN_CONT "(reserved)\n");
 391                         break;
 392                 case E820_ACPI:
 393                         printk(KERN_CONT "(ACPI data)\n");
 394                         break;
 395                 case E820_NVS:
 396                         printk(KERN_CONT "(ACPI NVS)\n");
 397                         break;
 398                 default:
 399                         printk(KERN_CONT "type %u\n", e820.map[i].type);
 400                         break;
 401                 }
 402         }
 403 }
 404
 405 /*
 406  * Sanitize the BIOS e820 map.
 407  *
 408  * Some e820 responses include overlapping entries. The following
 409  * replaces the original e820 map with a new one, removing overlaps.
 410  *
 411  */
 412 static int __init sanitize_e820_map(struct e820entry *biosmap, char *pnr_map)
 413 {
 414         struct change_member {
 415                 struct e820entry *pbios; /* pointer to original bios entry */
 416                 unsigned long long addr; /* address for this change point */
 417         };
 418         static struct change_member change_point_list[2*E820MAX] __initdata;
 419         static struct change_member *change_point[2*E820MAX] __initdata;
 420         static struct e820entry *overlap_list[E820MAX] __initdata;
 421         static struct e820entry new_bios[E820MAX] __initdata;
 422         struct change_member *change_tmp;
 423         unsigned long current_type, last_type;
 424         unsigned long long last_addr;
 425         int chgidx, still_changing;
 426         int overlap_entries;
 427         int new_bios_entry;
 428         int old_nr, new_nr, chg_nr;
 429         int i;
 430
 431         /*
 432                 Visually we're performing the following
 433                 (1,2,3,4 = memory types)...
 434
 435                 Sample memory map (w/overlaps):
 436                    ____22__________________
 437                    ______________________4_
 438                    ____1111________________
 439                    _44_____________________
 440                    11111111________________
 441                    ____________________33__
 442                    ___________44___________
 443                    __________33333_________
 444                    ______________22________
 445                    ___________________2222_
 446                    _________111111111______
 447                    _____________________11_
 448                    _________________4______
 449
 450                 Sanitized equivalent (no overlap):
 451                    1_______________________
 452                    _44_____________________
 453                    ___1____________________
 454                    ____22__________________
 455                    ______11________________
 456                    _________1______________
 457                    __________3_____________
 458                    ___________44___________
 459                    _____________33_________
 460                    _______________2________
 461                    ________________1_______
 462                    _________________4______
 463                    ___________________2____
 464                    ____________________33__
 465                    ______________________4_
 466         */
 467
 468         /* if there's only one memory region, don't bother */
 469         if (*pnr_map < 2)
 470                 return -1;
 471
 472         old_nr = *pnr_map;
 473
 474         /* bail out if we find any unreasonable addresses in bios map */
 475         for (i = 0; i < old_nr; i++)
 476                 if (biosmap[i].addr + biosmap[i].size < biosmap[i].addr)
 477                         return -1;
 478
 479         /* create pointers for initial change-point information (for sorting) */
 480         for (i = 0; i < 2 * old_nr; i++)
 481                 change_point[i] = &change_point_list[i];
 482
 483         /* record all known change-points (starting and ending addresses),
 484            omitting those that are for empty memory regions */
 485         chgidx = 0;
 486         for (i = 0; i < old_nr; i++)    {
 487                 if (biosmap[i].size != 0) {
 488                         change_point[chgidx]->addr = biosmap[i].addr;
 489                         change_point[chgidx++]->pbios = &biosmap[i];
 490                         change_point[chgidx]->addr = biosmap[i].addr +
 491                                 biosmap[i].size;
 492                         change_point[chgidx++]->pbios = &biosmap[i];
 493                 }
 494         }
 495         chg_nr = chgidx;
 496
 497         /* sort change-point list by memory addresses (low -> high) */
 498         still_changing = 1;
 499         while (still_changing)  {
 500                 still_changing = 0;
 501                 for (i = 1; i < chg_nr; i++)  {
 502                         unsigned long long curaddr, lastaddr;
 503                         unsigned long long curpbaddr, lastpbaddr;
 504
 505                         curaddr = change_point[i]->addr;
 506                         lastaddr = change_point[i - 1]->addr;
 507                         curpbaddr = change_point[i]->pbios->addr;
 508                         lastpbaddr = change_point[i - 1]->pbios->addr;
 509
 510                         /*
 511                          * swap entries, when:
 512                          *
 513                          * curaddr > lastaddr or
 514                          * curaddr == lastaddr and curaddr == curpbaddr and
 515                          * lastaddr != lastpbaddr
 516                          */
 517                         if (curaddr < lastaddr ||
 518                             (curaddr == lastaddr && curaddr == curpbaddr &&
 519                              lastaddr != lastpbaddr)) {
 520                                 change_tmp = change_point[i];
 521                                 change_point[i] = change_point[i-1];
 522                                 change_point[i-1] = change_tmp;
 523                                 still_changing = 1;
 524                         }
 525                 }
 526         }
 527
 528         /* create a new bios memory map, removing overlaps */
 529         overlap_entries = 0;     /* number of entries in the overlap table */
 530         new_bios_entry = 0;      /* index for creating new bios map entries */
 531         last_type = 0;           /* start with undefined memory type */
 532         last_addr = 0;           /* start with 0 as last starting address */
 533
 534         /* loop through change-points, determining affect on the new bios map */
 535         for (chgidx = 0; chgidx < chg_nr; chgidx++) {
 536                 /* keep track of all overlapping bios entries */
 537                 if (change_point[chgidx]->addr ==
 538                     change_point[chgidx]->pbios->addr) {
 539                         /*
 540                          * add map entry to overlap list (> 1 entry
 541                          * implies an overlap)
 542                          */
 543                         overlap_list[overlap_entries++] =
 544                                 change_point[chgidx]->pbios;
 545                 } else {
 546                         /*
 547                          * remove entry from list (order independent,
 548                          * so swap with last)
 549                          */
 550                         for (i = 0; i < overlap_entries; i++) {
 551                                 if (overlap_list[i] ==
 552                                     change_point[chgidx]->pbios)
 553                                         overlap_list[i] =
 554                                                 overlap_list[overlap_entries-1];
 555                         }
 556                         overlap_entries--;
 557                 }
 558                 /*
 559                  * if there are overlapping entries, decide which
 560                  * "type" to use (larger value takes precedence --
 561                  * 1=usable, 2,3,4,4+=unusable)
 562                  */
 563                 current_type = 0;
 564                 for (i = 0; i < overlap_entries; i++)
 565                         if (overlap_list[i]->type > current_type)
 566                                 current_type = overlap_list[i]->type;
 567                 /*
 568                  * continue building up new bios map based on this
 569                  * information
 570                  */
 571                 if (current_type != last_type)  {
 572                         if (last_type != 0)      {
 573                                 new_bios[new_bios_entry].size =
 574                                         change_point[chgidx]->addr - last_addr;
 575                                 /*
 576                                  * move forward only if the new size
 577                                  * was non-zero
 578                                  */
 579                                 if (new_bios[new_bios_entry].size != 0)
 580                                         /*
 581                                          * no more space left for new
 582                                          * bios entries ?
 583                                          */
 584                                         if (++new_bios_entry >= E820MAX)
 585                                                 break;
 586                         }
 587                         if (current_type != 0)  {
 588                                 new_bios[new_bios_entry].addr =
 589                                         change_point[chgidx]->addr;
 590                                 new_bios[new_bios_entry].type = current_type;
 591                                 last_addr = change_point[chgidx]->addr;
 592                         }
 593                         last_type = current_type;
 594                 }
 595         }
 596         /* retain count for new bios entries */
 597         new_nr = new_bios_entry;
 598
 599         /* copy new bios mapping into original location */
 600         memcpy(biosmap, new_bios, new_nr * sizeof(struct e820entry));
 601         *pnr_map = new_nr;
 602
 603         return 0;
 604 }
 605
 606 /*
 607  * Copy the BIOS e820 map into a safe place.
 608  *
 609  * Sanity-check it while we're at it..
 610  *
 611  * If we're lucky and live on a modern system, the setup code
 612  * will have given us a memory map that we can use to properly
 613  * set up memory.  If we aren't, we'll fake a memory map.
 614  */
 615 static int __init copy_e820_map(struct e820entry *biosmap, int nr_map)
 616 {
 617         /* Only one memory region (or negative)? Ignore it */
 618         if (nr_map < 2)
 619                 return -1;
 620
 621         do {
 622                 unsigned long start = biosmap->addr;
 623                 unsigned long size = biosmap->size;
 624                 unsigned long end = start + size;
 625                 unsigned long type = biosmap->type;
 626
 627                 /* Overflow in 64 bits? Ignore the memory map. */
 628                 if (start > end)
 629                         return -1;
 630
 631                 add_memory_region(start, size, type);
 632         } while (biosmap++, --nr_map);
 633         return 0;
 634 }
 635
 636 void early_panic(char *msg)
 637 {
 638         early_printk(msg);
 639         panic(msg);
 640 }
 641
 642 void __init setup_memory_region(void)
 643 {
 644         /*
 645          * Try to copy the BIOS-supplied E820-map.
 646          *
 647          * Otherwise fake a memory map; one section from 0k->640k,
 648          * the next section from 1mb->appropriate_mem_k
 649          */
 650         sanitize_e820_map(boot_params.e820_map, &boot_params.e820_entries);
 651         if (copy_e820_map(boot_params.e820_map, boot_params.e820_entries) < 0)
 652                 early_panic("Cannot find a valid memory map");
 653         printk(KERN_INFO "BIOS-provided physical RAM map:\n");
 654         e820_print_map("BIOS-e820");
 655 }
 656
 657 static int __init parse_memopt(char *p)
 658 {
 659         if (!p)
 660                 return -EINVAL;
 661         end_user_pfn = memparse(p, &p);
 662         end_user_pfn >>= PAGE_SHIFT;
 663         return 0;
 664 }
 665 early_param("mem", parse_memopt);
 666
 667 static int userdef __initdata;
 668
 669 static int __init parse_memmap_opt(char *p)
 670 {
 671         char *oldp;
 672         unsigned long long start_at, mem_size;
 673
 674         if (!strcmp(p, "exactmap")) {
 675 #ifdef CONFIG_CRASH_DUMP
 676                 /*
 677                  * If we are doing a crash dump, we still need to know
 678                  * the real mem size before original memory map is
 679                  * reset.
 680                  */
 681                 e820_register_active_regions(0, 0, -1UL);
 682                 saved_max_pfn = e820_end_of_ram();
 683                 remove_all_active_ranges();
 684 #endif
 685                 end_pfn_map = 0;
 686                 e820.nr_map = 0;
 687                 userdef = 1;
 688                 return 0;
 689         }
 690
 691         oldp = p;
 692         mem_size = memparse(p, &p);
 693         if (p == oldp)
 694                 return -EINVAL;
 695         if (*p == '@') {
 696                 start_at = memparse(p+1, &p);
 697                 add_memory_region(start_at, mem_size, E820_RAM);
 698         } else if (*p == '#') {
 699                 start_at = memparse(p+1, &p);
 700                 add_memory_region(start_at, mem_size, E820_ACPI);
 701         } else if (*p == '$') {
 702                 start_at = memparse(p+1, &p);
 703                 add_memory_region(start_at, mem_size, E820_RESERVED);
 704         } else {
 705                 end_user_pfn = (mem_size >> PAGE_SHIFT);
 706         }
 707         return *p == '\0' ? 0 : -EINVAL;
 708 }
 709 early_param("memmap", parse_memmap_opt);
 710
 711 void __init finish_e820_parsing(void)
 712 {
 713         if (userdef) {
 714                 printk(KERN_INFO "user-defined physical RAM map:\n");
 715                 e820_print_map("user");
 716         }
 717 }
 718
 719 unsigned long pci_mem_start = 0xaeedbabe;
 720 EXPORT_SYMBOL(pci_mem_start);
 721
 722 /*
 723  * Search for the biggest gap in the low 32 bits of the e820
 724  * memory space.  We pass this space to PCI to assign MMIO resources
 725  * for hotplug or unconfigured devices in.
 726  * Hopefully the BIOS let enough space left.
 727  */
 728 __init void e820_setup_gap(void)
 729 {
 730         unsigned long gapstart, gapsize, round;
 731         unsigned long last;
 732         int i;
 733         int found = 0;
 734
 735         last = 0x100000000ull;
 736         gapstart = 0x10000000;
 737         gapsize = 0x400000;
 738         i = e820.nr_map;
 739         while (--i >= 0) {
 740                 unsigned long long start = e820.map[i].addr;
 741                 unsigned long long end = start + e820.map[i].size;
 742
 743                 /*
 744                  * Since "last" is at most 4GB, we know we'll
 745                  * fit in 32 bits if this condition is true
 746                  */
 747                 if (last > end) {
 748                         unsigned long gap = last - end;
 749
 750                         if (gap > gapsize) {
 751                                 gapsize = gap;
 752                                 gapstart = end;
 753                                 found = 1;
 754                         }
 755                 }
 756                 if (start < last)
 757                         last = start;
 758         }
 759
 760         if (!found) {
 761                 gapstart = (end_pfn << PAGE_SHIFT) + 1024*1024;
 762                 printk(KERN_ERR "PCI: Warning: Cannot find a gap in the 32bit "
 763                        "address range\n"
 764                        KERN_ERR "PCI: Unassigned devices with 32bit resource "
 765                        "registers may break!\n");
 766         }
 767
 768         /*
 769          * See how much we want to round up: start off with
 770          * rounding to the next 1MB area.
 771          */
 772         round = 0x100000;
 773         while ((gapsize >> 4) > round)
 774                 round += round;
 775         /* Fun with two's complement */
 776         pci_mem_start = (gapstart + round) & -round;
 777
 778         printk(KERN_INFO
 779                "Allocating PCI resources starting at %lx (gap: %lx:%lx)\n",
 780                pci_mem_start, gapstart, gapsize);
 781 }
 782
 783 int __init arch_get_ram_range(int slot, u64 *addr, u64 *size)
 784 {
 785         int i;
 786
 787         if (slot < 0 || slot >= e820.nr_map)
 788                 return -1;
 789         for (i = slot; i < e820.nr_map; i++) {
 790                 if (e820.map[i].type != E820_RAM)
 791                         continue;
 792                 break;
 793         }
 794         if (i == e820.nr_map || e820.map[i].addr > (max_pfn << PAGE_SHIFT))
 795                 return -1;
 796         *addr = e820.map[i].addr;
 797         *size = min_t(u64, e820.map[i].size + e820.map[i].addr,
 798                 max_pfn << PAGE_SHIFT) - *addr;
 799         return i + 1;
 800 }