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 EXPORT_SYMBOL(end_pfn);
  38
  39 /*
  40  * end_pfn only includes RAM, while end_pfn_map includes all e820 entries.
  41  * The direct mapping extends to end_pfn_map, so that we can directly access
  42  * apertures, ACPI and other tables without having to play with fixmaps.
  43  */
  44 unsigned long end_pfn_map;
  45
  46 /*
  47  * Last pfn which the user wants to use.
  48  */
  49 static unsigned long __initdata end_user_pfn = MAXMEM>>PAGE_SHIFT;
  50
  51 extern struct resource code_resource, data_resource, bss_resource;
  52
  53 /* Check for some hardcoded bad areas that early boot is not allowed to touch */
  54 static inline int bad_addr(unsigned long *addrp, unsigned long size)
  55 {
  56         unsigned long addr = *addrp, last = addr + size;
  57
  58         /* various gunk below that needed for SMP startup */
  59         if (addr < 0x8000) {
  60                 *addrp = PAGE_ALIGN(0x8000);
  61                 return 1;
  62         }
  63
  64         /* direct mapping tables of the kernel */
  65         if (last >= table_start<<PAGE_SHIFT && addr < table_end<<PAGE_SHIFT) {
  66                 *addrp = PAGE_ALIGN(table_end << PAGE_SHIFT);
  67                 return 1;
  68         }
  69
  70         /* initrd */
  71 #ifdef CONFIG_BLK_DEV_INITRD
  72         if (boot_params.hdr.type_of_loader && boot_params.hdr.ramdisk_image) {
  73                 unsigned long ramdisk_image = boot_params.hdr.ramdisk_image;
  74                 unsigned long ramdisk_size  = boot_params.hdr.ramdisk_size;
  75                 unsigned long ramdisk_end   = ramdisk_image+ramdisk_size;
  76
  77                 if (last >= ramdisk_image && addr < ramdisk_end) {
  78                         *addrp = PAGE_ALIGN(ramdisk_end);
  79                         return 1;
  80                 }
  81         }
  82 #endif
  83         /* kernel code */
  84         if (last >= __pa_symbol(&_text) && addr < __pa_symbol(&_end)) {
  85                 *addrp = PAGE_ALIGN(__pa_symbol(&_end));
  86                 return 1;
  87         }
  88
  89         if (last >= ebda_addr && addr < ebda_addr + ebda_size) {
  90                 *addrp = PAGE_ALIGN(ebda_addr + ebda_size);
  91                 return 1;
  92         }
  93
  94 #ifdef CONFIG_NUMA
  95         /* NUMA memory to node map */
  96         if (last >= nodemap_addr && addr < nodemap_addr + nodemap_size) {
  97                 *addrp = nodemap_addr + nodemap_size;
  98                 return 1;
  99         }
 100 #endif
 101         /* XXX ramdisk image here? */
 102         return 0;
 103 }
 104
 105 /*
 106  * This function checks if any part of the range <start,end> is mapped
 107  * with type.
 108  */
 109 int
 110 e820_any_mapped(unsigned long start, unsigned long end, unsigned type)
 111 {
 112         int i;
 113
 114         for (i = 0; i < e820.nr_map; i++) {
 115                 struct e820entry *ei = &e820.map[i];
 116
 117                 if (type && ei->type != type)
 118                         continue;
 119                 if (ei->addr >= end || ei->addr + ei->size <= start)
 120                         continue;
 121                 return 1;
 122         }
 123         return 0;
 124 }
 125 EXPORT_SYMBOL_GPL(e820_any_mapped);
 126
 127 /*
 128  * This function checks if the entire range <start,end> is mapped with type.
 129  *
 130  * Note: this function only works correct if the e820 table is sorted and
 131  * not-overlapping, which is the case
 132  */
 133 int __init e820_all_mapped(unsigned long start, unsigned long end,
 134                            unsigned type)
 135 {
 136         int i;
 137
 138         for (i = 0; i < e820.nr_map; i++) {
 139                 struct e820entry *ei = &e820.map[i];
 140
 141                 if (type && ei->type != type)
 142                         continue;
 143                 /* is the region (part) in overlap with the current region ?*/
 144                 if (ei->addr >= end || ei->addr + ei->size <= start)
 145                         continue;
 146
 147                 /* if the region is at the beginning of <start,end> we move
 148                  * start to the end of the region since it's ok until there
 149                  */
 150                 if (ei->addr <= start)
 151                         start = ei->addr + ei->size;
 152                 /*
 153                  * if start is now at or beyond end, we're done, full
 154                  * coverage
 155                  */
 156                 if (start >= end)
 157                         return 1;
 158         }
 159         return 0;
 160 }
 161
 162 /*
 163  * Find a free area in a specific range.
 164  */
 165 unsigned long __init find_e820_area(unsigned long start, unsigned long end,
 166                                     unsigned size)
 167 {
 168         int i;
 169
 170         for (i = 0; i < e820.nr_map; i++) {
 171                 struct e820entry *ei = &e820.map[i];
 172                 unsigned long addr = ei->addr, last;
 173
 174                 if (ei->type != E820_RAM)
 175                         continue;
 176                 if (addr < start)
 177                         addr = start;
 178                 if (addr > ei->addr + ei->size)
 179                         continue;
 180                 while (bad_addr(&addr, size) && addr+size <= ei->addr+ei->size)
 181                         ;
 182                 last = PAGE_ALIGN(addr) + size;
 183                 if (last > ei->addr + ei->size)
 184                         continue;
 185                 if (last > end)
 186                         continue;
 187                 return addr;
 188         }
 189         return -1UL;
 190 }
 191
 192 /*
 193  * Find the highest page frame number we have available
 194  */
 195 unsigned long __init e820_end_of_ram(void)
 196 {
 197         unsigned long end_pfn;
 198
 199         end_pfn = find_max_pfn_with_active_regions();
 200
 201         if (end_pfn > end_pfn_map)
 202                 end_pfn_map = end_pfn;
 203         if (end_pfn_map > MAXMEM>>PAGE_SHIFT)
 204                 end_pfn_map = MAXMEM>>PAGE_SHIFT;
 205         if (end_pfn > end_user_pfn)
 206                 end_pfn = end_user_pfn;
 207         if (end_pfn > end_pfn_map)
 208                 end_pfn = end_pfn_map;
 209
 210         printk(KERN_INFO "end_pfn_map = %lu\n", end_pfn_map);
 211         return end_pfn;
 212 }
 213
 214 /*
 215  * Mark e820 reserved areas as busy for the resource manager.
 216  */
 217 void __init e820_reserve_resources(void)
 218 {
 219         int i;
 220         for (i = 0; i < e820.nr_map; i++) {
 221                 struct resource *res;
 222                 res = alloc_bootmem_low(sizeof(struct resource));
 223                 switch (e820.map[i].type) {
 224                 case E820_RAM:  res->name = "System RAM"; break;
 225                 case E820_ACPI: res->name = "ACPI Tables"; break;
 226                 case E820_NVS:  res->name = "ACPI Non-volatile Storage"; break;
 227                 default:        res->name = "reserved";
 228                 }
 229                 res->start = e820.map[i].addr;
 230                 res->end = res->start + e820.map[i].size - 1;
 231                 res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
 232                 request_resource(&iomem_resource, res);
 233                 if (e820.map[i].type == E820_RAM) {
 234                         /*
 235                          * We don't know which RAM region contains kernel data,
 236                          * so we try it repeatedly and let the resource manager
 237                          * test it.
 238                          */
 239                         request_resource(res, &code_resource);
 240                         request_resource(res, &data_resource);
 241                         request_resource(res, &bss_resource);
 242 #ifdef CONFIG_KEXEC
 243                         if (crashk_res.start != crashk_res.end)
 244                                 request_resource(res, &crashk_res);
 245 #endif
 246                 }
 247         }
 248 }
 249
 250 /*
 251  * Find the ranges of physical addresses that do not correspond to
 252  * e820 RAM areas and mark the corresponding pages as nosave for software
 253  * suspend and suspend to RAM.
 254  *
 255  * This function requires the e820 map to be sorted and without any
 256  * overlapping entries and assumes the first e820 area to be RAM.
 257  */
 258 void __init e820_mark_nosave_regions(void)
 259 {
 260         int i;
 261         unsigned long paddr;
 262
 263         paddr = round_down(e820.map[0].addr + e820.map[0].size, PAGE_SIZE);
 264         for (i = 1; i < e820.nr_map; i++) {
 265                 struct e820entry *ei = &e820.map[i];
 266
 267                 if (paddr < ei->addr)
 268                         register_nosave_region(PFN_DOWN(paddr),
 269                                                 PFN_UP(ei->addr));
 270
 271                 paddr = round_down(ei->addr + ei->size, PAGE_SIZE);
 272                 if (ei->type != E820_RAM)
 273                         register_nosave_region(PFN_UP(ei->addr),
 274                                                 PFN_DOWN(paddr));
 275
 276                 if (paddr >= (end_pfn << PAGE_SHIFT))
 277                         break;
 278         }
 279 }
 280
 281 /*
 282  * Finds an active region in the address range from start_pfn to end_pfn and
 283  * returns its range in ei_startpfn and ei_endpfn for the e820 entry.
 284  */
 285 static int __init e820_find_active_region(const struct e820entry *ei,
 286                                           unsigned long start_pfn,
 287                                           unsigned long end_pfn,
 288                                           unsigned long *ei_startpfn,
 289                                           unsigned long *ei_endpfn)
 290 {
 291         *ei_startpfn = round_up(ei->addr, PAGE_SIZE) >> PAGE_SHIFT;
 292         *ei_endpfn = round_down(ei->addr + ei->size, PAGE_SIZE) >> PAGE_SHIFT;
 293
 294         /* Skip map entries smaller than a page */
 295         if (*ei_startpfn >= *ei_endpfn)
 296                 return 0;
 297
 298         /* Check if end_pfn_map should be updated */
 299         if (ei->type != E820_RAM && *ei_endpfn > end_pfn_map)
 300                 end_pfn_map = *ei_endpfn;
 301
 302         /* Skip if map is outside the node */
 303         if (ei->type != E820_RAM || *ei_endpfn <= start_pfn ||
 304                                     *ei_startpfn >= end_pfn)
 305                 return 0;
 306
 307         /* Check for overlaps */
 308         if (*ei_startpfn < start_pfn)
 309                 *ei_startpfn = start_pfn;
 310         if (*ei_endpfn > end_pfn)
 311                 *ei_endpfn = end_pfn;
 312
 313         /* Obey end_user_pfn to save on memmap */
 314         if (*ei_startpfn >= end_user_pfn)
 315                 return 0;
 316         if (*ei_endpfn > end_user_pfn)
 317                 *ei_endpfn = end_user_pfn;
 318
 319         return 1;
 320 }
 321
 322 /* Walk the e820 map and register active regions within a node */
 323 void __init
 324 e820_register_active_regions(int nid, unsigned long start_pfn,
 325                                                         unsigned long end_pfn)
 326 {
 327         unsigned long ei_startpfn;
 328         unsigned long ei_endpfn;
 329         int i;
 330
 331         for (i = 0; i < e820.nr_map; i++)
 332                 if (e820_find_active_region(&e820.map[i],
 333                                             start_pfn, end_pfn,
 334                                             &ei_startpfn, &ei_endpfn))
 335                         add_active_range(nid, ei_startpfn, ei_endpfn);
 336 }
 337
 338 /*
 339  * Add a memory region to the kernel e820 map.
 340  */
 341 void __init add_memory_region(unsigned long start, unsigned long size, int type)
 342 {
 343         int x = e820.nr_map;
 344
 345         if (x == E820MAX) {
 346                 printk(KERN_ERR "Ooops! Too many entries in the memory map!\n");
 347                 return;
 348         }
 349
 350         e820.map[x].addr = start;
 351         e820.map[x].size = size;
 352         e820.map[x].type = type;
 353         e820.nr_map++;
 354 }
 355
 356 /*
 357  * Find the hole size (in bytes) in the memory range.
 358  * @start: starting address of the memory range to scan
 359  * @end: ending address of the memory range to scan
 360  */
 361 unsigned long __init e820_hole_size(unsigned long start, unsigned long end)
 362 {
 363         unsigned long start_pfn = start >> PAGE_SHIFT;
 364         unsigned long end_pfn = end >> PAGE_SHIFT;
 365         unsigned long ei_startpfn, ei_endpfn, ram = 0;
 366         int i;
 367
 368         for (i = 0; i < e820.nr_map; i++) {
 369                 if (e820_find_active_region(&e820.map[i],
 370                                             start_pfn, end_pfn,
 371                                             &ei_startpfn, &ei_endpfn))
 372                         ram += ei_endpfn - ei_startpfn;
 373         }
 374         return end - start - (ram << PAGE_SHIFT);
 375 }
 376
 377 void __init e820_print_map(char *who)
 378 {
 379         int i;
 380
 381         for (i = 0; i < e820.nr_map; i++) {
 382                 printk(KERN_INFO " %s: %016Lx - %016Lx ", who,
 383                        (unsigned long long) e820.map[i].addr,
 384                        (unsigned long long)
 385                        (e820.map[i].addr + e820.map[i].size));
 386                 switch (e820.map[i].type) {
 387                 case E820_RAM:
 388                         printk(KERN_CONT "(usable)\n");
 389                         break;
 390                 case E820_RESERVED:
 391                         printk(KERN_CONT "(reserved)\n");
 392                         break;
 393                 case E820_ACPI:
 394                         printk(KERN_CONT "(ACPI data)\n");
 395                         break;
 396                 case E820_NVS:
 397                         printk(KERN_CONT "(ACPI NVS)\n");
 398                         break;
 399                 default:
 400                         printk(KERN_CONT "type %u\n", e820.map[i].type);
 401                         break;
 402                 }
 403         }
 404 }
 405
 406 /*
 407  * Sanitize the BIOS e820 map.
 408  *
 409  * Some e820 responses include overlapping entries. The following
 410  * replaces the original e820 map with a new one, removing overlaps.
 411  *
 412  */
 413 static int __init sanitize_e820_map(struct e820entry *biosmap, char *pnr_map)
 414 {
 415         struct change_member {
 416                 struct e820entry *pbios; /* pointer to original bios entry */
 417                 unsigned long long addr; /* address for this change point */
 418         };
 419         static struct change_member change_point_list[2*E820MAX] __initdata;
 420         static struct change_member *change_point[2*E820MAX] __initdata;
 421         static struct e820entry *overlap_list[E820MAX] __initdata;
 422         static struct e820entry new_bios[E820MAX] __initdata;
 423         struct change_member *change_tmp;
 424         unsigned long current_type, last_type;
 425         unsigned long long last_addr;
 426         int chgidx, still_changing;
 427         int overlap_entries;
 428         int new_bios_entry;
 429         int old_nr, new_nr, chg_nr;
 430         int i;
 431
 432         /*
 433                 Visually we're performing the following
 434                 (1,2,3,4 = memory types)...
 435
 436                 Sample memory map (w/overlaps):
 437                    ____22__________________
 438                    ______________________4_
 439                    ____1111________________
 440                    _44_____________________
 441                    11111111________________
 442                    ____________________33__
 443                    ___________44___________
 444                    __________33333_________
 445                    ______________22________
 446                    ___________________2222_
 447                    _________111111111______
 448                    _____________________11_
 449                    _________________4______
 450
 451                 Sanitized equivalent (no overlap):
 452                    1_______________________
 453                    _44_____________________
 454                    ___1____________________
 455                    ____22__________________
 456                    ______11________________
 457                    _________1______________
 458                    __________3_____________
 459                    ___________44___________
 460                    _____________33_________
 461                    _______________2________
 462                    ________________1_______
 463                    _________________4______
 464                    ___________________2____
 465                    ____________________33__
 466                    ______________________4_
 467         */
 468
 469         /* if there's only one memory region, don't bother */
 470         if (*pnr_map < 2)
 471                 return -1;
 472
 473         old_nr = *pnr_map;
 474
 475         /* bail out if we find any unreasonable addresses in bios map */
 476         for (i = 0; i < old_nr; i++)
 477                 if (biosmap[i].addr + biosmap[i].size < biosmap[i].addr)
 478                         return -1;
 479
 480         /* create pointers for initial change-point information (for sorting) */
 481         for (i = 0; i < 2 * old_nr; i++)
 482                 change_point[i] = &change_point_list[i];
 483
 484         /* record all known change-points (starting and ending addresses),
 485            omitting those that are for empty memory regions */
 486         chgidx = 0;
 487         for (i = 0; i < old_nr; i++)    {
 488                 if (biosmap[i].size != 0) {
 489                         change_point[chgidx]->addr = biosmap[i].addr;
 490                         change_point[chgidx++]->pbios = &biosmap[i];
 491                         change_point[chgidx]->addr = biosmap[i].addr +
 492                                 biosmap[i].size;
 493                         change_point[chgidx++]->pbios = &biosmap[i];
 494                 }
 495         }
 496         chg_nr = chgidx;
 497
 498         /* sort change-point list by memory addresses (low -> high) */
 499         still_changing = 1;
 500         while (still_changing)  {
 501                 still_changing = 0;
 502                 for (i = 1; i < chg_nr; i++)  {
 503                         unsigned long long curaddr, lastaddr;
 504                         unsigned long long curpbaddr, lastpbaddr;
 505
 506                         curaddr = change_point[i]->addr;
 507                         lastaddr = change_point[i - 1]->addr;
 508                         curpbaddr = change_point[i]->pbios->addr;
 509                         lastpbaddr = change_point[i - 1]->pbios->addr;
 510
 511                         /*
 512                          * swap entries, when:
 513                          *
 514                          * curaddr > lastaddr or
 515                          * curaddr == lastaddr and curaddr == curpbaddr and
 516                          * lastaddr != lastpbaddr
 517                          */
 518                         if (curaddr < lastaddr ||
 519                             (curaddr == lastaddr && curaddr == curpbaddr &&
 520                              lastaddr != lastpbaddr)) {
 521                                 change_tmp = change_point[i];
 522                                 change_point[i] = change_point[i-1];
 523                                 change_point[i-1] = change_tmp;
 524                                 still_changing = 1;
 525                         }
 526                 }
 527         }
 528
 529         /* create a new bios memory map, removing overlaps */
 530         overlap_entries = 0;     /* number of entries in the overlap table */
 531         new_bios_entry = 0;      /* index for creating new bios map entries */
 532         last_type = 0;           /* start with undefined memory type */
 533         last_addr = 0;           /* start with 0 as last starting address */
 534
 535         /* loop through change-points, determining affect on the new bios map */
 536         for (chgidx = 0; chgidx < chg_nr; chgidx++) {
 537                 /* keep track of all overlapping bios entries */
 538                 if (change_point[chgidx]->addr ==
 539                     change_point[chgidx]->pbios->addr) {
 540                         /*
 541                          * add map entry to overlap list (> 1 entry
 542                          * implies an overlap)
 543                          */
 544                         overlap_list[overlap_entries++] =
 545                                 change_point[chgidx]->pbios;
 546                 } else {
 547                         /*
 548                          * remove entry from list (order independent,
 549                          * so swap with last)
 550                          */
 551                         for (i = 0; i < overlap_entries; i++) {
 552                                 if (overlap_list[i] ==
 553                                     change_point[chgidx]->pbios)
 554                                         overlap_list[i] =
 555                                                 overlap_list[overlap_entries-1];
 556                         }
 557                         overlap_entries--;
 558                 }
 559                 /*
 560                  * if there are overlapping entries, decide which
 561                  * "type" to use (larger value takes precedence --
 562                  * 1=usable, 2,3,4,4+=unusable)
 563                  */
 564                 current_type = 0;
 565                 for (i = 0; i < overlap_entries; i++)
 566                         if (overlap_list[i]->type > current_type)
 567                                 current_type = overlap_list[i]->type;
 568                 /*
 569                  * continue building up new bios map based on this
 570                  * information
 571                  */
 572                 if (current_type != last_type)  {
 573                         if (last_type != 0)      {
 574                                 new_bios[new_bios_entry].size =
 575                                         change_point[chgidx]->addr - last_addr;
 576                                 /*
 577                                  * move forward only if the new size
 578                                  * was non-zero
 579                                  */
 580                                 if (new_bios[new_bios_entry].size != 0)
 581                                         /*
 582                                          * no more space left for new
 583                                          * bios entries ?
 584                                          */
 585                                         if (++new_bios_entry >= E820MAX)
 586                                                 break;
 587                         }
 588                         if (current_type != 0)  {
 589                                 new_bios[new_bios_entry].addr =
 590                                         change_point[chgidx]->addr;
 591                                 new_bios[new_bios_entry].type = current_type;
 592                                 last_addr = change_point[chgidx]->addr;
 593                         }
 594                         last_type = current_type;
 595                 }
 596         }
 597         /* retain count for new bios entries */
 598         new_nr = new_bios_entry;
 599
 600         /* copy new bios mapping into original location */
 601         memcpy(biosmap, new_bios, new_nr * sizeof(struct e820entry));
 602         *pnr_map = new_nr;
 603
 604         return 0;
 605 }
 606
 607 /*
 608  * Copy the BIOS e820 map into a safe place.
 609  *
 610  * Sanity-check it while we're at it..
 611  *
 612  * If we're lucky and live on a modern system, the setup code
 613  * will have given us a memory map that we can use to properly
 614  * set up memory.  If we aren't, we'll fake a memory map.
 615  */
 616 static int __init copy_e820_map(struct e820entry *biosmap, int nr_map)
 617 {
 618         /* Only one memory region (or negative)? Ignore it */
 619         if (nr_map < 2)
 620                 return -1;
 621
 622         do {
 623                 unsigned long start = biosmap->addr;
 624                 unsigned long size = biosmap->size;
 625                 unsigned long end = start + size;
 626                 unsigned long type = biosmap->type;
 627
 628                 /* Overflow in 64 bits? Ignore the memory map. */
 629                 if (start > end)
 630                         return -1;
 631
 632                 add_memory_region(start, size, type);
 633         } while (biosmap++, --nr_map);
 634         return 0;
 635 }
 636
 637 void early_panic(char *msg)
 638 {
 639         early_printk(msg);
 640         panic(msg);
 641 }
 642
 643 void __init setup_memory_region(void)
 644 {
 645         /*
 646          * Try to copy the BIOS-supplied E820-map.
 647          *
 648          * Otherwise fake a memory map; one section from 0k->640k,
 649          * the next section from 1mb->appropriate_mem_k
 650          */
 651         sanitize_e820_map(boot_params.e820_map, &boot_params.e820_entries);
 652         if (copy_e820_map(boot_params.e820_map, boot_params.e820_entries) < 0)
 653                 early_panic("Cannot find a valid memory map");
 654         printk(KERN_INFO "BIOS-provided physical RAM map:\n");
 655         e820_print_map("BIOS-e820");
 656 }
 657
 658 static int __init parse_memopt(char *p)
 659 {
 660         if (!p)
 661                 return -EINVAL;
 662         end_user_pfn = memparse(p, &p);
 663         end_user_pfn >>= PAGE_SHIFT;
 664         return 0;
 665 }
 666 early_param("mem", parse_memopt);
 667
 668 static int userdef __initdata;
 669
 670 static int __init parse_memmap_opt(char *p)
 671 {
 672         char *oldp;
 673         unsigned long long start_at, mem_size;
 674
 675         if (!strcmp(p, "exactmap")) {
 676 #ifdef CONFIG_CRASH_DUMP
 677                 /*
 678                  * If we are doing a crash dump, we still need to know
 679                  * the real mem size before original memory map is
 680                  * reset.
 681                  */
 682                 e820_register_active_regions(0, 0, -1UL);
 683                 saved_max_pfn = e820_end_of_ram();
 684                 remove_all_active_ranges();
 685 #endif
 686                 end_pfn_map = 0;
 687                 e820.nr_map = 0;
 688                 userdef = 1;
 689                 return 0;
 690         }
 691
 692         oldp = p;
 693         mem_size = memparse(p, &p);
 694         if (p == oldp)
 695                 return -EINVAL;
 696         if (*p == '@') {
 697                 start_at = memparse(p+1, &p);
 698                 add_memory_region(start_at, mem_size, E820_RAM);
 699         } else if (*p == '#') {
 700                 start_at = memparse(p+1, &p);
 701                 add_memory_region(start_at, mem_size, E820_ACPI);
 702         } else if (*p == '$') {
 703                 start_at = memparse(p+1, &p);
 704                 add_memory_region(start_at, mem_size, E820_RESERVED);
 705         } else {
 706                 end_user_pfn = (mem_size >> PAGE_SHIFT);
 707         }
 708         return *p == '\0' ? 0 : -EINVAL;
 709 }
 710 early_param("memmap", parse_memmap_opt);
 711
 712 void __init finish_e820_parsing(void)
 713 {
 714         if (userdef) {
 715                 printk(KERN_INFO "user-defined physical RAM map:\n");
 716                 e820_print_map("user");
 717         }
 718 }
 719
 720 unsigned long pci_mem_start = 0xaeedbabe;
 721 EXPORT_SYMBOL(pci_mem_start);
 722
 723 /*
 724  * Search for the biggest gap in the low 32 bits of the e820
 725  * memory space.  We pass this space to PCI to assign MMIO resources
 726  * for hotplug or unconfigured devices in.
 727  * Hopefully the BIOS let enough space left.
 728  */
 729 __init void e820_setup_gap(void)
 730 {
 731         unsigned long gapstart, gapsize, round;
 732         unsigned long last;
 733         int i;
 734         int found = 0;
 735
 736         last = 0x100000000ull;
 737         gapstart = 0x10000000;
 738         gapsize = 0x400000;
 739         i = e820.nr_map;
 740         while (--i >= 0) {
 741                 unsigned long long start = e820.map[i].addr;
 742                 unsigned long long end = start + e820.map[i].size;
 743
 744                 /*
 745                  * Since "last" is at most 4GB, we know we'll
 746                  * fit in 32 bits if this condition is true
 747                  */
 748                 if (last > end) {
 749                         unsigned long gap = last - end;
 750
 751                         if (gap > gapsize) {
 752                                 gapsize = gap;
 753                                 gapstart = end;
 754                                 found = 1;
 755                         }
 756                 }
 757                 if (start < last)
 758                         last = start;
 759         }
 760
 761         if (!found) {
 762                 gapstart = (end_pfn << PAGE_SHIFT) + 1024*1024;
 763                 printk(KERN_ERR "PCI: Warning: Cannot find a gap in the 32bit "
 764                        "address range\n"
 765                        KERN_ERR "PCI: Unassigned devices with 32bit resource "
 766                        "registers may break!\n");
 767         }
 768
 769         /*
 770          * See how much we want to round up: start off with
 771          * rounding to the next 1MB area.
 772          */
 773         round = 0x100000;
 774         while ((gapsize >> 4) > round)
 775                 round += round;
 776         /* Fun with two's complement */
 777         pci_mem_start = (gapstart + round) & -round;
 778
 779         printk(KERN_INFO
 780                "Allocating PCI resources starting at %lx (gap: %lx:%lx)\n",
 781                pci_mem_start, gapstart, gapsize);
 782 }
 783
 784 int __init arch_get_ram_range(int slot, u64 *addr, u64 *size)
 785 {
 786         int i;
 787
 788         if (slot < 0 || slot >= e820.nr_map)
 789                 return -1;
 790         for (i = slot; i < e820.nr_map; i++) {
 791                 if (e820.map[i].type != E820_RAM)
 792                         continue;
 793                 break;
 794         }
 795         if (i == e820.nr_map || e820.map[i].addr > (max_pfn << PAGE_SHIFT))
 796                 return -1;
 797         *addr = e820.map[i].addr;
 798         *size = min_t(u64, e820.map[i].size + e820.map[i].addr,
 799                 max_pfn << PAGE_SHIFT) - *addr;
 800         return i + 1;
 801 }