arch/i386/kernel/e820.c

   1 #include <linux/kernel.h>
   2 #include <linux/types.h>
   3 #include <linux/init.h>
   4 #include <linux/bootmem.h>
   5 #include <linux/ioport.h>
   6 #include <linux/string.h>
   7 #include <linux/kexec.h>
   8 #include <linux/module.h>
   9 #include <linux/mm.h>
  10 #include <linux/efi.h>
  11 #include <linux/pfn.h>
  12 #include <linux/uaccess.h>
  13 #include <linux/suspend.h>
  14
  15 #include <asm/pgtable.h>
  16 #include <asm/page.h>
  17 #include <asm/e820.h>
  18 #include <asm/setup.h>
  19
  20 #ifdef CONFIG_EFI
  21 int efi_enabled = 0;
  22 EXPORT_SYMBOL(efi_enabled);
  23 #endif
  24
  25 struct e820map e820;
  26 struct change_member {
  27         struct e820entry *pbios; /* pointer to original bios entry */
  28         unsigned long long addr; /* address for this change point */
  29 };
  30 static struct change_member change_point_list[2*E820MAX] __initdata;
  31 static struct change_member *change_point[2*E820MAX] __initdata;
  32 static struct e820entry *overlap_list[E820MAX] __initdata;
  33 static struct e820entry new_bios[E820MAX] __initdata;
  34 /* For PCI or other memory-mapped resources */
  35 unsigned long pci_mem_start = 0x10000000;
  36 #ifdef CONFIG_PCI
  37 EXPORT_SYMBOL(pci_mem_start);
  38 #endif
  39 extern int user_defined_memmap;
  40 struct resource data_resource = {
  41         .name   = "Kernel data",
  42         .start  = 0,
  43         .end    = 0,
  44         .flags  = IORESOURCE_BUSY | IORESOURCE_MEM
  45 };
  46
  47 struct resource code_resource = {
  48         .name   = "Kernel code",
  49         .start  = 0,
  50         .end    = 0,
  51         .flags  = IORESOURCE_BUSY | IORESOURCE_MEM
  52 };
  53
  54 static struct resource system_rom_resource = {
  55         .name   = "System ROM",
  56         .start  = 0xf0000,
  57         .end    = 0xfffff,
  58         .flags  = IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
  59 };
  60
  61 static struct resource extension_rom_resource = {
  62         .name   = "Extension ROM",
  63         .start  = 0xe0000,
  64         .end    = 0xeffff,
  65         .flags  = IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
  66 };
  67
  68 static struct resource adapter_rom_resources[] = { {
  69         .name   = "Adapter ROM",
  70         .start  = 0xc8000,
  71         .end    = 0,
  72         .flags  = IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
  73 }, {
  74         .name   = "Adapter ROM",
  75         .start  = 0,
  76         .end    = 0,
  77         .flags  = IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
  78 }, {
  79         .name   = "Adapter ROM",
  80         .start  = 0,
  81         .end    = 0,
  82         .flags  = IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
  83 }, {
  84         .name   = "Adapter ROM",
  85         .start  = 0,
  86         .end    = 0,
  87         .flags  = IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
  88 }, {
  89         .name   = "Adapter ROM",
  90         .start  = 0,
  91         .end    = 0,
  92         .flags  = IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
  93 }, {
  94         .name   = "Adapter ROM",
  95         .start  = 0,
  96         .end    = 0,
  97         .flags  = IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
  98 } };
  99
 100 static struct resource video_rom_resource = {
 101         .name   = "Video ROM",
 102         .start  = 0xc0000,
 103         .end    = 0xc7fff,
 104         .flags  = IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
 105 };
 106
 107 static struct resource video_ram_resource = {
 108         .name   = "Video RAM area",
 109         .start  = 0xa0000,
 110         .end    = 0xbffff,
 111         .flags  = IORESOURCE_BUSY | IORESOURCE_MEM
 112 };
 113
 114 static struct resource standard_io_resources[] = { {
 115         .name   = "dma1",
 116         .start  = 0x0000,
 117         .end    = 0x001f,
 118         .flags  = IORESOURCE_BUSY | IORESOURCE_IO
 119 }, {
 120         .name   = "pic1",
 121         .start  = 0x0020,
 122         .end    = 0x0021,
 123         .flags  = IORESOURCE_BUSY | IORESOURCE_IO
 124 }, {
 125         .name   = "timer0",
 126         .start  = 0x0040,
 127         .end    = 0x0043,
 128         .flags  = IORESOURCE_BUSY | IORESOURCE_IO
 129 }, {
 130         .name   = "timer1",
 131         .start  = 0x0050,
 132         .end    = 0x0053,
 133         .flags  = IORESOURCE_BUSY | IORESOURCE_IO
 134 }, {
 135         .name   = "keyboard",
 136         .start  = 0x0060,
 137         .end    = 0x006f,
 138         .flags  = IORESOURCE_BUSY | IORESOURCE_IO
 139 }, {
 140         .name   = "dma page reg",
 141         .start  = 0x0080,
 142         .end    = 0x008f,
 143         .flags  = IORESOURCE_BUSY | IORESOURCE_IO
 144 }, {
 145         .name   = "pic2",
 146         .start  = 0x00a0,
 147         .end    = 0x00a1,
 148         .flags  = IORESOURCE_BUSY | IORESOURCE_IO
 149 }, {
 150         .name   = "dma2",
 151         .start  = 0x00c0,
 152         .end    = 0x00df,
 153         .flags  = IORESOURCE_BUSY | IORESOURCE_IO
 154 }, {
 155         .name   = "fpu",
 156         .start  = 0x00f0,
 157         .end    = 0x00ff,
 158         .flags  = IORESOURCE_BUSY | IORESOURCE_IO
 159 } };
 160
 161 #define ROMSIGNATURE 0xaa55
 162
 163 static int __init romsignature(const unsigned char *rom)
 164 {
 165         const unsigned short * const ptr = (const unsigned short *)rom;
 166         unsigned short sig;
 167
 168         return probe_kernel_address(ptr, sig) == 0 && sig == ROMSIGNATURE;
 169 }
 170
 171 static int __init romchecksum(const unsigned char *rom, unsigned long length)
 172 {
 173         unsigned char sum, c;
 174
 175         for (sum = 0; length && probe_kernel_address(rom++, c) == 0; length--)
 176                 sum += c;
 177         return !length && !sum;
 178 }
 179
 180 static void __init probe_roms(void)
 181 {
 182         const unsigned char *rom;
 183         unsigned long start, length, upper;
 184         unsigned char c;
 185         int i;
 186
 187         /* video rom */
 188         upper = adapter_rom_resources[0].start;
 189         for (start = video_rom_resource.start; start < upper; start += 2048) {
 190                 rom = isa_bus_to_virt(start);
 191                 if (!romsignature(rom))
 192                         continue;
 193
 194                 video_rom_resource.start = start;
 195
 196                 if (probe_kernel_address(rom + 2, c) != 0)
 197                         continue;
 198
 199                 /* 0 < length <= 0x7f * 512, historically */
 200                 length = c * 512;
 201
 202                 /* if checksum okay, trust length byte */
 203                 if (length && romchecksum(rom, length))
 204                         video_rom_resource.end = start + length - 1;
 205
 206                 request_resource(&iomem_resource, &video_rom_resource);
 207                 break;
 208         }
 209
 210         start = (video_rom_resource.end + 1 + 2047) & ~2047UL;
 211         if (start < upper)
 212                 start = upper;
 213
 214         /* system rom */
 215         request_resource(&iomem_resource, &system_rom_resource);
 216         upper = system_rom_resource.start;
 217
 218         /* check for extension rom (ignore length byte!) */
 219         rom = isa_bus_to_virt(extension_rom_resource.start);
 220         if (romsignature(rom)) {
 221                 length = extension_rom_resource.end - extension_rom_resource.start + 1;
 222                 if (romchecksum(rom, length)) {
 223                         request_resource(&iomem_resource, &extension_rom_resource);
 224                         upper = extension_rom_resource.start;
 225                 }
 226         }
 227
 228         /* check for adapter roms on 2k boundaries */
 229         for (i = 0; i < ARRAY_SIZE(adapter_rom_resources) && start < upper; start += 2048) {
 230                 rom = isa_bus_to_virt(start);
 231                 if (!romsignature(rom))
 232                         continue;
 233
 234                 if (probe_kernel_address(rom + 2, c) != 0)
 235                         continue;
 236
 237                 /* 0 < length <= 0x7f * 512, historically */
 238                 length = c * 512;
 239
 240                 /* but accept any length that fits if checksum okay */
 241                 if (!length || start + length > upper || !romchecksum(rom, length))
 242                         continue;
 243
 244                 adapter_rom_resources[i].start = start;
 245                 adapter_rom_resources[i].end = start + length - 1;
 246                 request_resource(&iomem_resource, &adapter_rom_resources[i]);
 247
 248                 start = adapter_rom_resources[i++].end & ~2047UL;
 249         }
 250 }
 251
 252 /*
 253  * Request address space for all standard RAM and ROM resources
 254  * and also for regions reported as reserved by the e820.
 255  */
 256 static void __init
 257 legacy_init_iomem_resources(struct resource *code_resource, struct resource *data_resource)
 258 {
 259         int i;
 260
 261         probe_roms();
 262         for (i = 0; i < e820.nr_map; i++) {
 263                 struct resource *res;
 264 #ifndef CONFIG_RESOURCES_64BIT
 265                 if (e820.map[i].addr + e820.map[i].size > 0x100000000ULL)
 266                         continue;
 267 #endif
 268                 res = kzalloc(sizeof(struct resource), GFP_ATOMIC);
 269                 switch (e820.map[i].type) {
 270                 case E820_RAM:  res->name = "System RAM"; break;
 271                 case E820_ACPI: res->name = "ACPI Tables"; break;
 272                 case E820_NVS:  res->name = "ACPI Non-volatile Storage"; break;
 273                 default:        res->name = "reserved";
 274                 }
 275                 res->start = e820.map[i].addr;
 276                 res->end = res->start + e820.map[i].size - 1;
 277                 res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
 278                 if (request_resource(&iomem_resource, res)) {
 279                         kfree(res);
 280                         continue;
 281                 }
 282                 if (e820.map[i].type == E820_RAM) {
 283                         /*
 284                          *  We don't know which RAM region contains kernel data,
 285                          *  so we try it repeatedly and let the resource manager
 286                          *  test it.
 287                          */
 288                         request_resource(res, code_resource);
 289                         request_resource(res, data_resource);
 290 #ifdef CONFIG_KEXEC
 291                         request_resource(res, &crashk_res);
 292 #endif
 293                 }
 294         }
 295 }
 296
 297 /*
 298  * Request address space for all standard resources
 299  *
 300  * This is called just before pcibios_init(), which is also a
 301  * subsys_initcall, but is linked in later (in arch/i386/pci/common.c).
 302  */
 303 static int __init request_standard_resources(void)
 304 {
 305         int i;
 306
 307         printk("Setting up standard PCI resources\n");
 308         if (efi_enabled)
 309                 efi_initialize_iomem_resources(&code_resource, &data_resource);
 310         else
 311                 legacy_init_iomem_resources(&code_resource, &data_resource);
 312
 313         /* EFI systems may still have VGA */
 314         request_resource(&iomem_resource, &video_ram_resource);
 315
 316         /* request I/O space for devices used on all i[345]86 PCs */
 317         for (i = 0; i < ARRAY_SIZE(standard_io_resources); i++)
 318                 request_resource(&ioport_resource, &standard_io_resources[i]);
 319         return 0;
 320 }
 321
 322 subsys_initcall(request_standard_resources);
 323
 324 #if defined(CONFIG_PM) && defined(CONFIG_SOFTWARE_SUSPEND)
 325 /**
 326  * e820_mark_nosave_regions - Find the ranges of physical addresses that do not
 327  * correspond to e820 RAM areas and mark the corresponding pages as nosave for
 328  * hibernation.
 329  *
 330  * This function requires the e820 map to be sorted and without any
 331  * overlapping entries and assumes the first e820 area to be RAM.
 332  */
 333 void __init e820_mark_nosave_regions(void)
 334 {
 335         int i;
 336         unsigned long pfn;
 337
 338         pfn = PFN_DOWN(e820.map[0].addr + e820.map[0].size);
 339         for (i = 1; i < e820.nr_map; i++) {
 340                 struct e820entry *ei = &e820.map[i];
 341
 342                 if (pfn < PFN_UP(ei->addr))
 343                         register_nosave_region(pfn, PFN_UP(ei->addr));
 344
 345                 pfn = PFN_DOWN(ei->addr + ei->size);
 346                 if (ei->type != E820_RAM)
 347                         register_nosave_region(PFN_UP(ei->addr), pfn);
 348
 349                 if (pfn >= max_low_pfn)
 350                         break;
 351         }
 352 }
 353 #endif
 354
 355 void __init add_memory_region(unsigned long long start,
 356                               unsigned long long size, int type)
 357 {
 358         int x;
 359
 360         if (!efi_enabled) {
 361                 x = e820.nr_map;
 362
 363                 if (x == E820MAX) {
 364                     printk(KERN_ERR "Ooops! Too many entries in the memory map!\n");
 365                     return;
 366                 }
 367
 368                 e820.map[x].addr = start;
 369                 e820.map[x].size = size;
 370                 e820.map[x].type = type;
 371                 e820.nr_map++;
 372         }
 373 } /* add_memory_region */
 374
 375 /*
 376  * Sanitize the BIOS e820 map.
 377  *
 378  * Some e820 responses include overlapping entries.  The following
 379  * replaces the original e820 map with a new one, removing overlaps.
 380  *
 381  */
 382 int __init sanitize_e820_map(struct e820entry * biosmap, char * pnr_map)
 383 {
 384         struct change_member *change_tmp;
 385         unsigned long current_type, last_type;
 386         unsigned long long last_addr;
 387         int chgidx, still_changing;
 388         int overlap_entries;
 389         int new_bios_entry;
 390         int old_nr, new_nr, chg_nr;
 391         int i;
 392
 393         /*
 394                 Visually we're performing the following (1,2,3,4 = memory types)...
 395
 396                 Sample memory map (w/overlaps):
 397                    ____22__________________
 398                    ______________________4_
 399                    ____1111________________
 400                    _44_____________________
 401                    11111111________________
 402                    ____________________33__
 403                    ___________44___________
 404                    __________33333_________
 405                    ______________22________
 406                    ___________________2222_
 407                    _________111111111______
 408                    _____________________11_
 409                    _________________4______
 410
 411                 Sanitized equivalent (no overlap):
 412                    1_______________________
 413                    _44_____________________
 414                    ___1____________________
 415                    ____22__________________
 416                    ______11________________
 417                    _________1______________
 418                    __________3_____________
 419                    ___________44___________
 420                    _____________33_________
 421                    _______________2________
 422                    ________________1_______
 423                    _________________4______
 424                    ___________________2____
 425                    ____________________33__
 426                    ______________________4_
 427         */
 428         /* if there's only one memory region, don't bother */
 429         if (*pnr_map < 2) {
 430                 return -1;
 431         }
 432
 433         old_nr = *pnr_map;
 434
 435         /* bail out if we find any unreasonable addresses in bios map */
 436         for (i=0; i<old_nr; i++)
 437                 if (biosmap[i].addr + biosmap[i].size < biosmap[i].addr) {
 438                         return -1;
 439                 }
 440
 441         /* create pointers for initial change-point information (for sorting) */
 442         for (i=0; i < 2*old_nr; i++)
 443                 change_point[i] = &change_point_list[i];
 444
 445         /* record all known change-points (starting and ending addresses),
 446            omitting those that are for empty memory regions */
 447         chgidx = 0;
 448         for (i=0; i < old_nr; i++)      {
 449                 if (biosmap[i].size != 0) {
 450                         change_point[chgidx]->addr = biosmap[i].addr;
 451                         change_point[chgidx++]->pbios = &biosmap[i];
 452                         change_point[chgidx]->addr = biosmap[i].addr + biosmap[i].size;
 453                         change_point[chgidx++]->pbios = &biosmap[i];
 454                 }
 455         }
 456         chg_nr = chgidx;        /* true number of change-points */
 457
 458         /* sort change-point list by memory addresses (low -> high) */
 459         still_changing = 1;
 460         while (still_changing)  {
 461                 still_changing = 0;
 462                 for (i=1; i < chg_nr; i++)  {
 463                         /* if <current_addr> > <last_addr>, swap */
 464                         /* or, if current=<start_addr> & last=<end_addr>, swap */
 465                         if ((change_point[i]->addr < change_point[i-1]->addr) ||
 466                                 ((change_point[i]->addr == change_point[i-1]->addr) &&
 467                                  (change_point[i]->addr == change_point[i]->pbios->addr) &&
 468                                  (change_point[i-1]->addr != change_point[i-1]->pbios->addr))
 469                            )
 470                         {
 471                                 change_tmp = change_point[i];
 472                                 change_point[i] = change_point[i-1];
 473                                 change_point[i-1] = change_tmp;
 474                                 still_changing=1;
 475                         }
 476                 }
 477         }
 478
 479         /* create a new bios memory map, removing overlaps */
 480         overlap_entries=0;       /* number of entries in the overlap table */
 481         new_bios_entry=0;        /* index for creating new bios map entries */
 482         last_type = 0;           /* start with undefined memory type */
 483         last_addr = 0;           /* start with 0 as last starting address */
 484         /* loop through change-points, determining affect on the new bios map */
 485         for (chgidx=0; chgidx < chg_nr; chgidx++)
 486         {
 487                 /* keep track of all overlapping bios entries */
 488                 if (change_point[chgidx]->addr == change_point[chgidx]->pbios->addr)
 489                 {
 490                         /* add map entry to overlap list (> 1 entry implies an overlap) */
 491                         overlap_list[overlap_entries++]=change_point[chgidx]->pbios;
 492                 }
 493                 else
 494                 {
 495                         /* remove entry from list (order independent, so swap with last) */
 496                         for (i=0; i<overlap_entries; i++)
 497                         {
 498                                 if (overlap_list[i] == change_point[chgidx]->pbios)
 499                                         overlap_list[i] = overlap_list[overlap_entries-1];
 500                         }
 501                         overlap_entries--;
 502                 }
 503                 /* if there are overlapping entries, decide which "type" to use */
 504                 /* (larger value takes precedence -- 1=usable, 2,3,4,4+=unusable) */
 505                 current_type = 0;
 506                 for (i=0; i<overlap_entries; i++)
 507                         if (overlap_list[i]->type > current_type)
 508                                 current_type = overlap_list[i]->type;
 509                 /* continue building up new bios map based on this information */
 510                 if (current_type != last_type)  {
 511                         if (last_type != 0)      {
 512                                 new_bios[new_bios_entry].size =
 513                                         change_point[chgidx]->addr - last_addr;
 514                                 /* move forward only if the new size was non-zero */
 515                                 if (new_bios[new_bios_entry].size != 0)
 516                                         if (++new_bios_entry >= E820MAX)
 517                                                 break;  /* no more space left for new bios entries */
 518                         }
 519                         if (current_type != 0)  {
 520                                 new_bios[new_bios_entry].addr = change_point[chgidx]->addr;
 521                                 new_bios[new_bios_entry].type = current_type;
 522                                 last_addr=change_point[chgidx]->addr;
 523                         }
 524                         last_type = current_type;
 525                 }
 526         }
 527         new_nr = new_bios_entry;   /* retain count for new bios entries */
 528
 529         /* copy new bios mapping into original location */
 530         memcpy(biosmap, new_bios, new_nr*sizeof(struct e820entry));
 531         *pnr_map = new_nr;
 532
 533         return 0;
 534 }
 535
 536 /*
 537  * Copy the BIOS e820 map into a safe place.
 538  *
 539  * Sanity-check it while we're at it..
 540  *
 541  * If we're lucky and live on a modern system, the setup code
 542  * will have given us a memory map that we can use to properly
 543  * set up memory.  If we aren't, we'll fake a memory map.
 544  *
 545  * We check to see that the memory map contains at least 2 elements
 546  * before we'll use it, because the detection code in setup.S may
 547  * not be perfect and most every PC known to man has two memory
 548  * regions: one from 0 to 640k, and one from 1mb up.  (The IBM
 549  * thinkpad 560x, for example, does not cooperate with the memory
 550  * detection code.)
 551  */
 552 int __init copy_e820_map(struct e820entry * biosmap, int nr_map)
 553 {
 554         /* Only one memory region (or negative)? Ignore it */
 555         if (nr_map < 2)
 556                 return -1;
 557
 558         do {
 559                 unsigned long long start = biosmap->addr;
 560                 unsigned long long size = biosmap->size;
 561                 unsigned long long end = start + size;
 562                 unsigned long type = biosmap->type;
 563
 564                 /* Overflow in 64 bits? Ignore the memory map. */
 565                 if (start > end)
 566                         return -1;
 567
 568                 /*
 569                  * Some BIOSes claim RAM in the 640k - 1M region.
 570                  * Not right. Fix it up.
 571                  */
 572                 if (type == E820_RAM) {
 573                         if (start < 0x100000ULL && end > 0xA0000ULL) {
 574                                 if (start < 0xA0000ULL)
 575                                         add_memory_region(start, 0xA0000ULL-start, type);
 576                                 if (end <= 0x100000ULL)
 577                                         continue;
 578                                 start = 0x100000ULL;
 579                                 size = end - start;
 580                         }
 581                 }
 582                 add_memory_region(start, size, type);
 583         } while (biosmap++,--nr_map);
 584         return 0;
 585 }
 586
 587 /*
 588  * Callback for efi_memory_walk.
 589  */
 590 static int __init
 591 efi_find_max_pfn(unsigned long start, unsigned long end, void *arg)
 592 {
 593         unsigned long *max_pfn = arg, pfn;
 594
 595         if (start < end) {
 596                 pfn = PFN_UP(end -1);
 597                 if (pfn > *max_pfn)
 598                         *max_pfn = pfn;
 599         }
 600         return 0;
 601 }
 602
 603 static int __init
 604 efi_memory_present_wrapper(unsigned long start, unsigned long end, void *arg)
 605 {
 606         memory_present(0, PFN_UP(start), PFN_DOWN(end));
 607         return 0;
 608 }
 609
 610 /*
 611  * Find the highest page frame number we have available
 612  */
 613 void __init find_max_pfn(void)
 614 {
 615         int i;
 616
 617         max_pfn = 0;
 618         if (efi_enabled) {
 619                 efi_memmap_walk(efi_find_max_pfn, &max_pfn);
 620                 efi_memmap_walk(efi_memory_present_wrapper, NULL);
 621                 return;
 622         }
 623
 624         for (i = 0; i < e820.nr_map; i++) {
 625                 unsigned long start, end;
 626                 /* RAM? */
 627                 if (e820.map[i].type != E820_RAM)
 628                         continue;
 629                 start = PFN_UP(e820.map[i].addr);
 630                 end = PFN_DOWN(e820.map[i].addr + e820.map[i].size);
 631                 if (start >= end)
 632                         continue;
 633                 if (end > max_pfn)
 634                         max_pfn = end;
 635                 memory_present(0, start, end);
 636         }
 637 }
 638
 639 /*
 640  * Free all available memory for boot time allocation.  Used
 641  * as a callback function by efi_memory_walk()
 642  */
 643
 644 static int __init
 645 free_available_memory(unsigned long start, unsigned long end, void *arg)
 646 {
 647         /* check max_low_pfn */
 648         if (start >= (max_low_pfn << PAGE_SHIFT))
 649                 return 0;
 650         if (end >= (max_low_pfn << PAGE_SHIFT))
 651                 end = max_low_pfn << PAGE_SHIFT;
 652         if (start < end)
 653                 free_bootmem(start, end - start);
 654
 655         return 0;
 656 }
 657 /*
 658  * Register fully available low RAM pages with the bootmem allocator.
 659  */
 660 void __init register_bootmem_low_pages(unsigned long max_low_pfn)
 661 {
 662         int i;
 663
 664         if (efi_enabled) {
 665                 efi_memmap_walk(free_available_memory, NULL);
 666                 return;
 667         }
 668         for (i = 0; i < e820.nr_map; i++) {
 669                 unsigned long curr_pfn, last_pfn, size;
 670                 /*
 671                  * Reserve usable low memory
 672                  */
 673                 if (e820.map[i].type != E820_RAM)
 674                         continue;
 675                 /*
 676                  * We are rounding up the start address of usable memory:
 677                  */
 678                 curr_pfn = PFN_UP(e820.map[i].addr);
 679                 if (curr_pfn >= max_low_pfn)
 680                         continue;
 681                 /*
 682                  * ... and at the end of the usable range downwards:
 683                  */
 684                 last_pfn = PFN_DOWN(e820.map[i].addr + e820.map[i].size);
 685
 686                 if (last_pfn > max_low_pfn)
 687                         last_pfn = max_low_pfn;
 688
 689                 /*
 690                  * .. finally, did all the rounding and playing
 691                  * around just make the area go away?
 692                  */
 693                 if (last_pfn <= curr_pfn)
 694                         continue;
 695
 696                 size = last_pfn - curr_pfn;
 697                 free_bootmem(PFN_PHYS(curr_pfn), PFN_PHYS(size));
 698         }
 699 }
 700
 701 void __init e820_register_memory(void)
 702 {
 703         unsigned long gapstart, gapsize, round;
 704         unsigned long long last;
 705         int i;
 706
 707         /*
 708          * Search for the bigest gap in the low 32 bits of the e820
 709          * memory space.
 710          */
 711         last = 0x100000000ull;
 712         gapstart = 0x10000000;
 713         gapsize = 0x400000;
 714         i = e820.nr_map;
 715         while (--i >= 0) {
 716                 unsigned long long start = e820.map[i].addr;
 717                 unsigned long long end = start + e820.map[i].size;
 718
 719                 /*
 720                  * Since "last" is at most 4GB, we know we'll
 721                  * fit in 32 bits if this condition is true
 722                  */
 723                 if (last > end) {
 724                         unsigned long gap = last - end;
 725
 726                         if (gap > gapsize) {
 727                                 gapsize = gap;
 728                                 gapstart = end;
 729                         }
 730                 }
 731                 if (start < last)
 732                         last = start;
 733         }
 734
 735         /*
 736          * See how much we want to round up: start off with
 737          * rounding to the next 1MB area.
 738          */
 739         round = 0x100000;
 740         while ((gapsize >> 4) > round)
 741                 round += round;
 742         /* Fun with two's complement */
 743         pci_mem_start = (gapstart + round) & -round;
 744
 745         printk("Allocating PCI resources starting at %08lx (gap: %08lx:%08lx)\n",
 746                 pci_mem_start, gapstart, gapsize);
 747 }
 748
 749 void __init print_memory_map(char *who)
 750 {
 751         int i;
 752
 753         for (i = 0; i < e820.nr_map; i++) {
 754                 printk(" %s: %016Lx - %016Lx ", who,
 755                         e820.map[i].addr,
 756                         e820.map[i].addr + e820.map[i].size);
 757                 switch (e820.map[i].type) {
 758                 case E820_RAM:  printk("(usable)\n");
 759                                 break;
 760                 case E820_RESERVED:
 761                                 printk("(reserved)\n");
 762                                 break;
 763                 case E820_ACPI:
 764                                 printk("(ACPI data)\n");
 765                                 break;
 766                 case E820_NVS:
 767                                 printk("(ACPI NVS)\n");
 768                                 break;
 769                 default:        printk("type %u\n", e820.map[i].type);
 770                                 break;
 771                 }
 772         }
 773 }
 774
 775 static __init __always_inline void efi_limit_regions(unsigned long long size)
 776 {
 777         unsigned long long current_addr = 0;
 778         efi_memory_desc_t *md, *next_md;
 779         void *p, *p1;
 780         int i, j;
 781
 782         j = 0;
 783         p1 = memmap.map;
 784         for (p = p1, i = 0; p < memmap.map_end; p += memmap.desc_size, i++) {
 785                 md = p;
 786                 next_md = p1;
 787                 current_addr = md->phys_addr +
 788                         PFN_PHYS(md->num_pages);
 789                 if (is_available_memory(md)) {
 790                         if (md->phys_addr >= size) continue;
 791                         memcpy(next_md, md, memmap.desc_size);
 792                         if (current_addr >= size) {
 793                                 next_md->num_pages -=
 794                                         PFN_UP(current_addr-size);
 795                         }
 796                         p1 += memmap.desc_size;
 797                         next_md = p1;
 798                         j++;
 799                 } else if ((md->attribute & EFI_MEMORY_RUNTIME) ==
 800                            EFI_MEMORY_RUNTIME) {
 801                         /* In order to make runtime services
 802                          * available we have to include runtime
 803                          * memory regions in memory map */
 804                         memcpy(next_md, md, memmap.desc_size);
 805                         p1 += memmap.desc_size;
 806                         next_md = p1;
 807                         j++;
 808                 }
 809         }
 810         memmap.nr_map = j;
 811         memmap.map_end = memmap.map +
 812                 (memmap.nr_map * memmap.desc_size);
 813 }
 814
 815 void __init limit_regions(unsigned long long size)
 816 {
 817         unsigned long long current_addr;
 818         int i;
 819
 820         print_memory_map("limit_regions start");
 821         if (efi_enabled) {
 822                 efi_limit_regions(size);
 823                 return;
 824         }
 825         for (i = 0; i < e820.nr_map; i++) {
 826                 current_addr = e820.map[i].addr + e820.map[i].size;
 827                 if (current_addr < size)
 828                         continue;
 829
 830                 if (e820.map[i].type != E820_RAM)
 831                         continue;
 832
 833                 if (e820.map[i].addr >= size) {
 834                         /*
 835                          * This region starts past the end of the
 836                          * requested size, skip it completely.
 837                          */
 838                         e820.nr_map = i;
 839                 } else {
 840                         e820.nr_map = i + 1;
 841                         e820.map[i].size -= current_addr - size;
 842                 }
 843                 print_memory_map("limit_regions endfor");
 844                 return;
 845         }
 846         print_memory_map("limit_regions endfunc");
 847 }
 848
 849 /*
 850  * This function checks if any part of the range <start,end> is mapped
 851  * with type.
 852  */
 853 int
 854 e820_any_mapped(u64 start, u64 end, unsigned type)
 855 {
 856         int i;
 857         for (i = 0; i < e820.nr_map; i++) {
 858                 const struct e820entry *ei = &e820.map[i];
 859                 if (type && ei->type != type)
 860                         continue;
 861                 if (ei->addr >= end || ei->addr + ei->size <= start)
 862                         continue;
 863                 return 1;
 864         }
 865         return 0;
 866 }
 867 EXPORT_SYMBOL_GPL(e820_any_mapped);
 868
 869  /*
 870   * This function checks if the entire range <start,end> is mapped with type.
 871   *
 872   * Note: this function only works correct if the e820 table is sorted and
 873   * not-overlapping, which is the case
 874   */
 875 int __init
 876 e820_all_mapped(unsigned long s, unsigned long e, unsigned type)
 877 {
 878         u64 start = s;
 879         u64 end = e;
 880         int i;
 881         for (i = 0; i < e820.nr_map; i++) {
 882                 struct e820entry *ei = &e820.map[i];
 883                 if (type && ei->type != type)
 884                         continue;
 885                 /* is the region (part) in overlap with the current region ?*/
 886                 if (ei->addr >= end || ei->addr + ei->size <= start)
 887                         continue;
 888                 /* if the region is at the beginning of <start,end> we move
 889                  * start to the end of the region since it's ok until there
 890                  */
 891                 if (ei->addr <= start)
 892                         start = ei->addr + ei->size;
 893                 /* if start is now at or beyond end, we're done, full
 894                  * coverage */
 895                 if (start >= end)
 896                         return 1; /* we're done */
 897         }
 898         return 0;
 899 }
 900
 901 static int __init parse_memmap(char *arg)
 902 {
 903         if (!arg)
 904                 return -EINVAL;
 905
 906         if (strcmp(arg, "exactmap") == 0) {
 907 #ifdef CONFIG_CRASH_DUMP
 908                 /* If we are doing a crash dump, we
 909                  * still need to know the real mem
 910                  * size before original memory map is
 911                  * reset.
 912                  */
 913                 find_max_pfn();
 914                 saved_max_pfn = max_pfn;
 915 #endif
 916                 e820.nr_map = 0;
 917                 user_defined_memmap = 1;
 918         } else {
 919                 /* If the user specifies memory size, we
 920                  * limit the BIOS-provided memory map to
 921                  * that size. exactmap can be used to specify
 922                  * the exact map. mem=number can be used to
 923                  * trim the existing memory map.
 924                  */
 925                 unsigned long long start_at, mem_size;
 926
 927                 mem_size = memparse(arg, &arg);
 928                 if (*arg == '@') {
 929                         start_at = memparse(arg+1, &arg);
 930                         add_memory_region(start_at, mem_size, E820_RAM);
 931                 } else if (*arg == '#') {
 932                         start_at = memparse(arg+1, &arg);
 933                         add_memory_region(start_at, mem_size, E820_ACPI);
 934                 } else if (*arg == '$') {
 935                         start_at = memparse(arg+1, &arg);
 936                         add_memory_region(start_at, mem_size, E820_RESERVED);
 937                 } else {
 938                         limit_regions(mem_size);
 939                         user_defined_memmap = 1;
 940                 }
 941         }
 942         return 0;
 943 }
 944 early_param("memmap", parse_memmap);