arch/x86/kernel/e820_32.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 struct resource bss_resource = {
  55         .name   = "Kernel bss",
  56         .start  = 0,
  57         .end    = 0,
  58         .flags  = IORESOURCE_BUSY | IORESOURCE_MEM
  59 };
  60
  61 static struct resource system_rom_resource = {
  62         .name   = "System ROM",
  63         .start  = 0xf0000,
  64         .end    = 0xfffff,
  65         .flags  = IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
  66 };
  67
  68 static struct resource extension_rom_resource = {
  69         .name   = "Extension ROM",
  70         .start  = 0xe0000,
  71         .end    = 0xeffff,
  72         .flags  = IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
  73 };
  74
  75 static struct resource adapter_rom_resources[] = { {
  76         .name   = "Adapter ROM",
  77         .start  = 0xc8000,
  78         .end    = 0,
  79         .flags  = IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
  80 }, {
  81         .name   = "Adapter ROM",
  82         .start  = 0,
  83         .end    = 0,
  84         .flags  = IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
  85 }, {
  86         .name   = "Adapter ROM",
  87         .start  = 0,
  88         .end    = 0,
  89         .flags  = IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
  90 }, {
  91         .name   = "Adapter ROM",
  92         .start  = 0,
  93         .end    = 0,
  94         .flags  = IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
  95 }, {
  96         .name   = "Adapter ROM",
  97         .start  = 0,
  98         .end    = 0,
  99         .flags  = IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
 100 }, {
 101         .name   = "Adapter ROM",
 102         .start  = 0,
 103         .end    = 0,
 104         .flags  = IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
 105 } };
 106
 107 static struct resource video_rom_resource = {
 108         .name   = "Video ROM",
 109         .start  = 0xc0000,
 110         .end    = 0xc7fff,
 111         .flags  = IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
 112 };
 113
 114 static struct resource video_ram_resource = {
 115         .name   = "Video RAM area",
 116         .start  = 0xa0000,
 117         .end    = 0xbffff,
 118         .flags  = IORESOURCE_BUSY | IORESOURCE_MEM
 119 };
 120
 121 static struct resource standard_io_resources[] = { {
 122         .name   = "dma1",
 123         .start  = 0x0000,
 124         .end    = 0x001f,
 125         .flags  = IORESOURCE_BUSY | IORESOURCE_IO
 126 }, {
 127         .name   = "pic1",
 128         .start  = 0x0020,
 129         .end    = 0x0021,
 130         .flags  = IORESOURCE_BUSY | IORESOURCE_IO
 131 }, {
 132         .name   = "timer0",
 133         .start  = 0x0040,
 134         .end    = 0x0043,
 135         .flags  = IORESOURCE_BUSY | IORESOURCE_IO
 136 }, {
 137         .name   = "timer1",
 138         .start  = 0x0050,
 139         .end    = 0x0053,
 140         .flags  = IORESOURCE_BUSY | IORESOURCE_IO
 141 }, {
 142         .name   = "keyboard",
 143         .start  = 0x0060,
 144         .end    = 0x006f,
 145         .flags  = IORESOURCE_BUSY | IORESOURCE_IO
 146 }, {
 147         .name   = "dma page reg",
 148         .start  = 0x0080,
 149         .end    = 0x008f,
 150         .flags  = IORESOURCE_BUSY | IORESOURCE_IO
 151 }, {
 152         .name   = "pic2",
 153         .start  = 0x00a0,
 154         .end    = 0x00a1,
 155         .flags  = IORESOURCE_BUSY | IORESOURCE_IO
 156 }, {
 157         .name   = "dma2",
 158         .start  = 0x00c0,
 159         .end    = 0x00df,
 160         .flags  = IORESOURCE_BUSY | IORESOURCE_IO
 161 }, {
 162         .name   = "fpu",
 163         .start  = 0x00f0,
 164         .end    = 0x00ff,
 165         .flags  = IORESOURCE_BUSY | IORESOURCE_IO
 166 } };
 167
 168 #define ROMSIGNATURE 0xaa55
 169
 170 static int __init romsignature(const unsigned char *rom)
 171 {
 172         const unsigned short * const ptr = (const unsigned short *)rom;
 173         unsigned short sig;
 174
 175         return probe_kernel_address(ptr, sig) == 0 && sig == ROMSIGNATURE;
 176 }
 177
 178 static int __init romchecksum(const unsigned char *rom, unsigned long length)
 179 {
 180         unsigned char sum, c;
 181
 182         for (sum = 0; length && probe_kernel_address(rom++, c) == 0; length--)
 183                 sum += c;
 184         return !length && !sum;
 185 }
 186
 187 static void __init probe_roms(void)
 188 {
 189         const unsigned char *rom;
 190         unsigned long start, length, upper;
 191         unsigned char c;
 192         int i;
 193
 194         /* video rom */
 195         upper = adapter_rom_resources[0].start;
 196         for (start = video_rom_resource.start; start < upper; start += 2048) {
 197                 rom = isa_bus_to_virt(start);
 198                 if (!romsignature(rom))
 199                         continue;
 200
 201                 video_rom_resource.start = start;
 202
 203                 if (probe_kernel_address(rom + 2, c) != 0)
 204                         continue;
 205
 206                 /* 0 < length <= 0x7f * 512, historically */
 207                 length = c * 512;
 208
 209                 /* if checksum okay, trust length byte */
 210                 if (length && romchecksum(rom, length))
 211                         video_rom_resource.end = start + length - 1;
 212
 213                 request_resource(&iomem_resource, &video_rom_resource);
 214                 break;
 215         }
 216
 217         start = (video_rom_resource.end + 1 + 2047) & ~2047UL;
 218         if (start < upper)
 219                 start = upper;
 220
 221         /* system rom */
 222         request_resource(&iomem_resource, &system_rom_resource);
 223         upper = system_rom_resource.start;
 224
 225         /* check for extension rom (ignore length byte!) */
 226         rom = isa_bus_to_virt(extension_rom_resource.start);
 227         if (romsignature(rom)) {
 228                 length = extension_rom_resource.end - extension_rom_resource.start + 1;
 229                 if (romchecksum(rom, length)) {
 230                         request_resource(&iomem_resource, &extension_rom_resource);
 231                         upper = extension_rom_resource.start;
 232                 }
 233         }
 234
 235         /* check for adapter roms on 2k boundaries */
 236         for (i = 0; i < ARRAY_SIZE(adapter_rom_resources) && start < upper; start += 2048) {
 237                 rom = isa_bus_to_virt(start);
 238                 if (!romsignature(rom))
 239                         continue;
 240
 241                 if (probe_kernel_address(rom + 2, c) != 0)
 242                         continue;
 243
 244                 /* 0 < length <= 0x7f * 512, historically */
 245                 length = c * 512;
 246
 247                 /* but accept any length that fits if checksum okay */
 248                 if (!length || start + length > upper || !romchecksum(rom, length))
 249                         continue;
 250
 251                 adapter_rom_resources[i].start = start;
 252                 adapter_rom_resources[i].end = start + length - 1;
 253                 request_resource(&iomem_resource, &adapter_rom_resources[i]);
 254
 255                 start = adapter_rom_resources[i++].end & ~2047UL;
 256         }
 257 }
 258
 259 /*
 260  * Request address space for all standard RAM and ROM resources
 261  * and also for regions reported as reserved by the e820.
 262  */
 263 static void __init
 264 legacy_init_iomem_resources(struct resource *code_resource,
 265                             struct resource *data_resource,
 266                             struct resource *bss_resource)
 267 {
 268         int i;
 269
 270         probe_roms();
 271         for (i = 0; i < e820.nr_map; i++) {
 272                 struct resource *res;
 273 #ifndef CONFIG_RESOURCES_64BIT
 274                 if (e820.map[i].addr + e820.map[i].size > 0x100000000ULL)
 275                         continue;
 276 #endif
 277                 res = kzalloc(sizeof(struct resource), GFP_ATOMIC);
 278                 switch (e820.map[i].type) {
 279                 case E820_RAM:  res->name = "System RAM"; break;
 280                 case E820_ACPI: res->name = "ACPI Tables"; break;
 281                 case E820_NVS:  res->name = "ACPI Non-volatile Storage"; break;
 282                 default:        res->name = "reserved";
 283                 }
 284                 res->start = e820.map[i].addr;
 285                 res->end = res->start + e820.map[i].size - 1;
 286                 res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
 287                 if (request_resource(&iomem_resource, res)) {
 288                         kfree(res);
 289                         continue;
 290                 }
 291                 if (e820.map[i].type == E820_RAM) {
 292                         /*
 293                          *  We don't know which RAM region contains kernel data,
 294                          *  so we try it repeatedly and let the resource manager
 295                          *  test it.
 296                          */
 297                         request_resource(res, code_resource);
 298                         request_resource(res, data_resource);
 299                         request_resource(res, bss_resource);
 300 #ifdef CONFIG_KEXEC
 301                         if (crashk_res.start != crashk_res.end)
 302                                 request_resource(res, &crashk_res);
 303 #endif
 304                 }
 305         }
 306 }
 307
 308 /*
 309  * Request address space for all standard resources
 310  *
 311  * This is called just before pcibios_init(), which is also a
 312  * subsys_initcall, but is linked in later (in arch/i386/pci/common.c).
 313  */
 314 static int __init request_standard_resources(void)
 315 {
 316         int i;
 317
 318         printk("Setting up standard PCI resources\n");
 319         if (efi_enabled)
 320                 efi_initialize_iomem_resources(&code_resource,
 321                                 &data_resource, &bss_resource);
 322         else
 323                 legacy_init_iomem_resources(&code_resource,
 324                                 &data_resource, &bss_resource);
 325
 326         /* EFI systems may still have VGA */
 327         request_resource(&iomem_resource, &video_ram_resource);
 328
 329         /* request I/O space for devices used on all i[345]86 PCs */
 330         for (i = 0; i < ARRAY_SIZE(standard_io_resources); i++)
 331                 request_resource(&ioport_resource, &standard_io_resources[i]);
 332         return 0;
 333 }
 334
 335 subsys_initcall(request_standard_resources);
 336
 337 #if defined(CONFIG_PM) && defined(CONFIG_HIBERNATION)
 338 /**
 339  * e820_mark_nosave_regions - Find the ranges of physical addresses that do not
 340  * correspond to e820 RAM areas and mark the corresponding pages as nosave for
 341  * hibernation.
 342  *
 343  * This function requires the e820 map to be sorted and without any
 344  * overlapping entries and assumes the first e820 area to be RAM.
 345  */
 346 void __init e820_mark_nosave_regions(void)
 347 {
 348         int i;
 349         unsigned long pfn;
 350
 351         pfn = PFN_DOWN(e820.map[0].addr + e820.map[0].size);
 352         for (i = 1; i < e820.nr_map; i++) {
 353                 struct e820entry *ei = &e820.map[i];
 354
 355                 if (pfn < PFN_UP(ei->addr))
 356                         register_nosave_region(pfn, PFN_UP(ei->addr));
 357
 358                 pfn = PFN_DOWN(ei->addr + ei->size);
 359                 if (ei->type != E820_RAM)
 360                         register_nosave_region(PFN_UP(ei->addr), pfn);
 361
 362                 if (pfn >= max_low_pfn)
 363                         break;
 364         }
 365 }
 366 #endif
 367
 368 void __init add_memory_region(unsigned long long start,
 369                               unsigned long long size, int type)
 370 {
 371         int x;
 372
 373         if (!efi_enabled) {
 374                 x = e820.nr_map;
 375
 376                 if (x == E820MAX) {
 377                     printk(KERN_ERR "Ooops! Too many entries in the memory map!\n");
 378                     return;
 379                 }
 380
 381                 e820.map[x].addr = start;
 382                 e820.map[x].size = size;
 383                 e820.map[x].type = type;
 384                 e820.nr_map++;
 385         }
 386 } /* add_memory_region */
 387
 388 /*
 389  * Sanitize the BIOS e820 map.
 390  *
 391  * Some e820 responses include overlapping entries.  The following
 392  * replaces the original e820 map with a new one, removing overlaps.
 393  *
 394  */
 395 int __init sanitize_e820_map(struct e820entry * biosmap, char * pnr_map)
 396 {
 397         struct change_member *change_tmp;
 398         unsigned long current_type, last_type;
 399         unsigned long long last_addr;
 400         int chgidx, still_changing;
 401         int overlap_entries;
 402         int new_bios_entry;
 403         int old_nr, new_nr, chg_nr;
 404         int i;
 405
 406         /*
 407                 Visually we're performing the following (1,2,3,4 = memory types)...
 408
 409                 Sample memory map (w/overlaps):
 410                    ____22__________________
 411                    ______________________4_
 412                    ____1111________________
 413                    _44_____________________
 414                    11111111________________
 415                    ____________________33__
 416                    ___________44___________
 417                    __________33333_________
 418                    ______________22________
 419                    ___________________2222_
 420                    _________111111111______
 421                    _____________________11_
 422                    _________________4______
 423
 424                 Sanitized equivalent (no overlap):
 425                    1_______________________
 426                    _44_____________________
 427                    ___1____________________
 428                    ____22__________________
 429                    ______11________________
 430                    _________1______________
 431                    __________3_____________
 432                    ___________44___________
 433                    _____________33_________
 434                    _______________2________
 435                    ________________1_______
 436                    _________________4______
 437                    ___________________2____
 438                    ____________________33__
 439                    ______________________4_
 440         */
 441         /* if there's only one memory region, don't bother */
 442         if (*pnr_map < 2) {
 443                 return -1;
 444         }
 445
 446         old_nr = *pnr_map;
 447
 448         /* bail out if we find any unreasonable addresses in bios map */
 449         for (i=0; i<old_nr; i++)
 450                 if (biosmap[i].addr + biosmap[i].size < biosmap[i].addr) {
 451                         return -1;
 452                 }
 453
 454         /* create pointers for initial change-point information (for sorting) */
 455         for (i=0; i < 2*old_nr; i++)
 456                 change_point[i] = &change_point_list[i];
 457
 458         /* record all known change-points (starting and ending addresses),
 459            omitting those that are for empty memory regions */
 460         chgidx = 0;
 461         for (i=0; i < old_nr; i++)      {
 462                 if (biosmap[i].size != 0) {
 463                         change_point[chgidx]->addr = biosmap[i].addr;
 464                         change_point[chgidx++]->pbios = &biosmap[i];
 465                         change_point[chgidx]->addr = biosmap[i].addr + biosmap[i].size;
 466                         change_point[chgidx++]->pbios = &biosmap[i];
 467                 }
 468         }
 469         chg_nr = chgidx;        /* true number of change-points */
 470
 471         /* sort change-point list by memory addresses (low -> high) */
 472         still_changing = 1;
 473         while (still_changing)  {
 474                 still_changing = 0;
 475                 for (i=1; i < chg_nr; i++)  {
 476                         /* if <current_addr> > <last_addr>, swap */
 477                         /* or, if current=<start_addr> & last=<end_addr>, swap */
 478                         if ((change_point[i]->addr < change_point[i-1]->addr) ||
 479                                 ((change_point[i]->addr == change_point[i-1]->addr) &&
 480                                  (change_point[i]->addr == change_point[i]->pbios->addr) &&
 481                                  (change_point[i-1]->addr != change_point[i-1]->pbios->addr))
 482                            )
 483                         {
 484                                 change_tmp = change_point[i];
 485                                 change_point[i] = change_point[i-1];
 486                                 change_point[i-1] = change_tmp;
 487                                 still_changing=1;
 488                         }
 489                 }
 490         }
 491
 492         /* create a new bios memory map, removing overlaps */
 493         overlap_entries=0;       /* number of entries in the overlap table */
 494         new_bios_entry=0;        /* index for creating new bios map entries */
 495         last_type = 0;           /* start with undefined memory type */
 496         last_addr = 0;           /* start with 0 as last starting address */
 497         /* loop through change-points, determining affect on the new bios map */
 498         for (chgidx=0; chgidx < chg_nr; chgidx++)
 499         {
 500                 /* keep track of all overlapping bios entries */
 501                 if (change_point[chgidx]->addr == change_point[chgidx]->pbios->addr)
 502                 {
 503                         /* add map entry to overlap list (> 1 entry implies an overlap) */
 504                         overlap_list[overlap_entries++]=change_point[chgidx]->pbios;
 505                 }
 506                 else
 507                 {
 508                         /* remove entry from list (order independent, so swap with last) */
 509                         for (i=0; i<overlap_entries; i++)
 510                         {
 511                                 if (overlap_list[i] == change_point[chgidx]->pbios)
 512                                         overlap_list[i] = overlap_list[overlap_entries-1];
 513                         }
 514                         overlap_entries--;
 515                 }
 516                 /* if there are overlapping entries, decide which "type" to use */
 517                 /* (larger value takes precedence -- 1=usable, 2,3,4,4+=unusable) */
 518                 current_type = 0;
 519                 for (i=0; i<overlap_entries; i++)
 520                         if (overlap_list[i]->type > current_type)
 521                                 current_type = overlap_list[i]->type;
 522                 /* continue building up new bios map based on this information */
 523                 if (current_type != last_type)  {
 524                         if (last_type != 0)      {
 525                                 new_bios[new_bios_entry].size =
 526                                         change_point[chgidx]->addr - last_addr;
 527                                 /* move forward only if the new size was non-zero */
 528                                 if (new_bios[new_bios_entry].size != 0)
 529                                         if (++new_bios_entry >= E820MAX)
 530                                                 break;  /* no more space left for new bios entries */
 531                         }
 532                         if (current_type != 0)  {
 533                                 new_bios[new_bios_entry].addr = change_point[chgidx]->addr;
 534                                 new_bios[new_bios_entry].type = current_type;
 535                                 last_addr=change_point[chgidx]->addr;
 536                         }
 537                         last_type = current_type;
 538                 }
 539         }
 540         new_nr = new_bios_entry;   /* retain count for new bios entries */
 541
 542         /* copy new bios mapping into original location */
 543         memcpy(biosmap, new_bios, new_nr*sizeof(struct e820entry));
 544         *pnr_map = new_nr;
 545
 546         return 0;
 547 }
 548
 549 /*
 550  * Copy the BIOS e820 map into a safe place.
 551  *
 552  * Sanity-check it while we're at it..
 553  *
 554  * If we're lucky and live on a modern system, the setup code
 555  * will have given us a memory map that we can use to properly
 556  * set up memory.  If we aren't, we'll fake a memory map.
 557  *
 558  * We check to see that the memory map contains at least 2 elements
 559  * before we'll use it, because the detection code in setup.S may
 560  * not be perfect and most every PC known to man has two memory
 561  * regions: one from 0 to 640k, and one from 1mb up.  (The IBM
 562  * thinkpad 560x, for example, does not cooperate with the memory
 563  * detection code.)
 564  */
 565 int __init copy_e820_map(struct e820entry * biosmap, int nr_map)
 566 {
 567         /* Only one memory region (or negative)? Ignore it */
 568         if (nr_map < 2)
 569                 return -1;
 570
 571         do {
 572                 unsigned long long start = biosmap->addr;
 573                 unsigned long long size = biosmap->size;
 574                 unsigned long long end = start + size;
 575                 unsigned long type = biosmap->type;
 576
 577                 /* Overflow in 64 bits? Ignore the memory map. */
 578                 if (start > end)
 579                         return -1;
 580
 581                 /*
 582                  * Some BIOSes claim RAM in the 640k - 1M region.
 583                  * Not right. Fix it up.
 584                  */
 585                 if (type == E820_RAM) {
 586                         if (start < 0x100000ULL && end > 0xA0000ULL) {
 587                                 if (start < 0xA0000ULL)
 588                                         add_memory_region(start, 0xA0000ULL-start, type);
 589                                 if (end <= 0x100000ULL)
 590                                         continue;
 591                                 start = 0x100000ULL;
 592                                 size = end - start;
 593                         }
 594                 }
 595                 add_memory_region(start, size, type);
 596         } while (biosmap++,--nr_map);
 597         return 0;
 598 }
 599
 600 /*
 601  * Callback for efi_memory_walk.
 602  */
 603 static int __init
 604 efi_find_max_pfn(unsigned long start, unsigned long end, void *arg)
 605 {
 606         unsigned long *max_pfn = arg, pfn;
 607
 608         if (start < end) {
 609                 pfn = PFN_UP(end -1);
 610                 if (pfn > *max_pfn)
 611                         *max_pfn = pfn;
 612         }
 613         return 0;
 614 }
 615
 616 static int __init
 617 efi_memory_present_wrapper(unsigned long start, unsigned long end, void *arg)
 618 {
 619         memory_present(0, PFN_UP(start), PFN_DOWN(end));
 620         return 0;
 621 }
 622
 623 /*
 624  * Find the highest page frame number we have available
 625  */
 626 void __init find_max_pfn(void)
 627 {
 628         int i;
 629
 630         max_pfn = 0;
 631         if (efi_enabled) {
 632                 efi_memmap_walk(efi_find_max_pfn, &max_pfn);
 633                 efi_memmap_walk(efi_memory_present_wrapper, NULL);
 634                 return;
 635         }
 636
 637         for (i = 0; i < e820.nr_map; i++) {
 638                 unsigned long start, end;
 639                 /* RAM? */
 640                 if (e820.map[i].type != E820_RAM)
 641                         continue;
 642                 start = PFN_UP(e820.map[i].addr);
 643                 end = PFN_DOWN(e820.map[i].addr + e820.map[i].size);
 644                 if (start >= end)
 645                         continue;
 646                 if (end > max_pfn)
 647                         max_pfn = end;
 648                 memory_present(0, start, end);
 649         }
 650 }
 651
 652 /*
 653  * Free all available memory for boot time allocation.  Used
 654  * as a callback function by efi_memory_walk()
 655  */
 656
 657 static int __init
 658 free_available_memory(unsigned long start, unsigned long end, void *arg)
 659 {
 660         /* check max_low_pfn */
 661         if (start >= (max_low_pfn << PAGE_SHIFT))
 662                 return 0;
 663         if (end >= (max_low_pfn << PAGE_SHIFT))
 664                 end = max_low_pfn << PAGE_SHIFT;
 665         if (start < end)
 666                 free_bootmem(start, end - start);
 667
 668         return 0;
 669 }
 670 /*
 671  * Register fully available low RAM pages with the bootmem allocator.
 672  */
 673 void __init register_bootmem_low_pages(unsigned long max_low_pfn)
 674 {
 675         int i;
 676
 677         if (efi_enabled) {
 678                 efi_memmap_walk(free_available_memory, NULL);
 679                 return;
 680         }
 681         for (i = 0; i < e820.nr_map; i++) {
 682                 unsigned long curr_pfn, last_pfn, size;
 683                 /*
 684                  * Reserve usable low memory
 685                  */
 686                 if (e820.map[i].type != E820_RAM)
 687                         continue;
 688                 /*
 689                  * We are rounding up the start address of usable memory:
 690                  */
 691                 curr_pfn = PFN_UP(e820.map[i].addr);
 692                 if (curr_pfn >= max_low_pfn)
 693                         continue;
 694                 /*
 695                  * ... and at the end of the usable range downwards:
 696                  */
 697                 last_pfn = PFN_DOWN(e820.map[i].addr + e820.map[i].size);
 698
 699                 if (last_pfn > max_low_pfn)
 700                         last_pfn = max_low_pfn;
 701
 702                 /*
 703                  * .. finally, did all the rounding and playing
 704                  * around just make the area go away?
 705                  */
 706                 if (last_pfn <= curr_pfn)
 707                         continue;
 708
 709                 size = last_pfn - curr_pfn;
 710                 free_bootmem(PFN_PHYS(curr_pfn), PFN_PHYS(size));
 711         }
 712 }
 713
 714 void __init e820_register_memory(void)
 715 {
 716         unsigned long gapstart, gapsize, round;
 717         unsigned long long last;
 718         int i;
 719
 720         /*
 721          * Search for the biggest gap in the low 32 bits of the e820
 722          * memory space.
 723          */
 724         last = 0x100000000ull;
 725         gapstart = 0x10000000;
 726         gapsize = 0x400000;
 727         i = e820.nr_map;
 728         while (--i >= 0) {
 729                 unsigned long long start = e820.map[i].addr;
 730                 unsigned long long end = start + e820.map[i].size;
 731
 732                 /*
 733                  * Since "last" is at most 4GB, we know we'll
 734                  * fit in 32 bits if this condition is true
 735                  */
 736                 if (last > end) {
 737                         unsigned long gap = last - end;
 738
 739                         if (gap > gapsize) {
 740                                 gapsize = gap;
 741                                 gapstart = end;
 742                         }
 743                 }
 744                 if (start < last)
 745                         last = start;
 746         }
 747
 748         /*
 749          * See how much we want to round up: start off with
 750          * rounding to the next 1MB area.
 751          */
 752         round = 0x100000;
 753         while ((gapsize >> 4) > round)
 754                 round += round;
 755         /* Fun with two's complement */
 756         pci_mem_start = (gapstart + round) & -round;
 757
 758         printk("Allocating PCI resources starting at %08lx (gap: %08lx:%08lx)\n",
 759                 pci_mem_start, gapstart, gapsize);
 760 }
 761
 762 void __init print_memory_map(char *who)
 763 {
 764         int i;
 765
 766         for (i = 0; i < e820.nr_map; i++) {
 767                 printk(" %s: %016Lx - %016Lx ", who,
 768                         e820.map[i].addr,
 769                         e820.map[i].addr + e820.map[i].size);
 770                 switch (e820.map[i].type) {
 771                 case E820_RAM:  printk("(usable)\n");
 772                                 break;
 773                 case E820_RESERVED:
 774                                 printk("(reserved)\n");
 775                                 break;
 776                 case E820_ACPI:
 777                                 printk("(ACPI data)\n");
 778                                 break;
 779                 case E820_NVS:
 780                                 printk("(ACPI NVS)\n");
 781                                 break;
 782                 default:        printk("type %u\n", e820.map[i].type);
 783                                 break;
 784                 }
 785         }
 786 }
 787
 788 static __init __always_inline void efi_limit_regions(unsigned long long size)
 789 {
 790         unsigned long long current_addr = 0;
 791         efi_memory_desc_t *md, *next_md;
 792         void *p, *p1;
 793         int i, j;
 794
 795         j = 0;
 796         p1 = memmap.map;
 797         for (p = p1, i = 0; p < memmap.map_end; p += memmap.desc_size, i++) {
 798                 md = p;
 799                 next_md = p1;
 800                 current_addr = md->phys_addr +
 801                         PFN_PHYS(md->num_pages);
 802                 if (is_available_memory(md)) {
 803                         if (md->phys_addr >= size) continue;
 804                         memcpy(next_md, md, memmap.desc_size);
 805                         if (current_addr >= size) {
 806                                 next_md->num_pages -=
 807                                         PFN_UP(current_addr-size);
 808                         }
 809                         p1 += memmap.desc_size;
 810                         next_md = p1;
 811                         j++;
 812                 } else if ((md->attribute & EFI_MEMORY_RUNTIME) ==
 813                            EFI_MEMORY_RUNTIME) {
 814                         /* In order to make runtime services
 815                          * available we have to include runtime
 816                          * memory regions in memory map */
 817                         memcpy(next_md, md, memmap.desc_size);
 818                         p1 += memmap.desc_size;
 819                         next_md = p1;
 820                         j++;
 821                 }
 822         }
 823         memmap.nr_map = j;
 824         memmap.map_end = memmap.map +
 825                 (memmap.nr_map * memmap.desc_size);
 826 }
 827
 828 void __init limit_regions(unsigned long long size)
 829 {
 830         unsigned long long current_addr;
 831         int i;
 832
 833         print_memory_map("limit_regions start");
 834         if (efi_enabled) {
 835                 efi_limit_regions(size);
 836                 return;
 837         }
 838         for (i = 0; i < e820.nr_map; i++) {
 839                 current_addr = e820.map[i].addr + e820.map[i].size;
 840                 if (current_addr < size)
 841                         continue;
 842
 843                 if (e820.map[i].type != E820_RAM)
 844                         continue;
 845
 846                 if (e820.map[i].addr >= size) {
 847                         /*
 848                          * This region starts past the end of the
 849                          * requested size, skip it completely.
 850                          */
 851                         e820.nr_map = i;
 852                 } else {
 853                         e820.nr_map = i + 1;
 854                         e820.map[i].size -= current_addr - size;
 855                 }
 856                 print_memory_map("limit_regions endfor");
 857                 return;
 858         }
 859         print_memory_map("limit_regions endfunc");
 860 }
 861
 862 /*
 863  * This function checks if any part of the range <start,end> is mapped
 864  * with type.
 865  */
 866 int
 867 e820_any_mapped(u64 start, u64 end, unsigned type)
 868 {
 869         int i;
 870         for (i = 0; i < e820.nr_map; i++) {
 871                 const struct e820entry *ei = &e820.map[i];
 872                 if (type && ei->type != type)
 873                         continue;
 874                 if (ei->addr >= end || ei->addr + ei->size <= start)
 875                         continue;
 876                 return 1;
 877         }
 878         return 0;
 879 }
 880 EXPORT_SYMBOL_GPL(e820_any_mapped);
 881
 882  /*
 883   * This function checks if the entire range <start,end> is mapped with type.
 884   *
 885   * Note: this function only works correct if the e820 table is sorted and
 886   * not-overlapping, which is the case
 887   */
 888 int __init
 889 e820_all_mapped(unsigned long s, unsigned long e, unsigned type)
 890 {
 891         u64 start = s;
 892         u64 end = e;
 893         int i;
 894         for (i = 0; i < e820.nr_map; i++) {
 895                 struct e820entry *ei = &e820.map[i];
 896                 if (type && ei->type != type)
 897                         continue;
 898                 /* is the region (part) in overlap with the current region ?*/
 899                 if (ei->addr >= end || ei->addr + ei->size <= start)
 900                         continue;
 901                 /* if the region is at the beginning of <start,end> we move
 902                  * start to the end of the region since it's ok until there
 903                  */
 904                 if (ei->addr <= start)
 905                         start = ei->addr + ei->size;
 906                 /* if start is now at or beyond end, we're done, full
 907                  * coverage */
 908                 if (start >= end)
 909                         return 1; /* we're done */
 910         }
 911         return 0;
 912 }
 913
 914 static int __init parse_memmap(char *arg)
 915 {
 916         if (!arg)
 917                 return -EINVAL;
 918
 919         if (strcmp(arg, "exactmap") == 0) {
 920 #ifdef CONFIG_CRASH_DUMP
 921                 /* If we are doing a crash dump, we
 922                  * still need to know the real mem
 923                  * size before original memory map is
 924                  * reset.
 925                  */
 926                 find_max_pfn();
 927                 saved_max_pfn = max_pfn;
 928 #endif
 929                 e820.nr_map = 0;
 930                 user_defined_memmap = 1;
 931         } else {
 932                 /* If the user specifies memory size, we
 933                  * limit the BIOS-provided memory map to
 934                  * that size. exactmap can be used to specify
 935                  * the exact map. mem=number can be used to
 936                  * trim the existing memory map.
 937                  */
 938                 unsigned long long start_at, mem_size;
 939
 940                 mem_size = memparse(arg, &arg);
 941                 if (*arg == '@') {
 942                         start_at = memparse(arg+1, &arg);
 943                         add_memory_region(start_at, mem_size, E820_RAM);
 944                 } else if (*arg == '#') {
 945                         start_at = memparse(arg+1, &arg);
 946                         add_memory_region(start_at, mem_size, E820_ACPI);
 947                 } else if (*arg == '$') {
 948                         start_at = memparse(arg+1, &arg);
 949                         add_memory_region(start_at, mem_size, E820_RESERVED);
 950                 } else {
 951                         limit_regions(mem_size);
 952                         user_defined_memmap = 1;
 953                 }
 954         }
 955         return 0;
 956 }
 957 early_param("memmap", parse_memmap);