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