arch/x86/kernel/e820_64.c

   1 /*
   2  * Handle the memory map.
   3  * The functions here do the job until bootmem takes over.
   4  *
   5  *  Getting sanitize_e820_map() in sync with i386 version by applying change:
   6  *  -  Provisions for empty E820 memory regions (reported by certain BIOSes).
   7  *     Alex Achenbach <xela@slit.de>, December 2002.
   8  *  Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
   9  *
  10  */
  11 #include <linux/kernel.h>
  12 #include <linux/types.h>
  13 #include <linux/init.h>
  14 #include <linux/bootmem.h>
  15 #include <linux/ioport.h>
  16 #include <linux/string.h>
  17 #include <linux/kexec.h>
  18 #include <linux/module.h>
  19 #include <linux/mm.h>
  20 #include <linux/suspend.h>
  21 #include <linux/pfn.h>
  22
  23 #include <asm/pgtable.h>
  24 #include <asm/page.h>
  25 #include <asm/e820.h>
  26 #include <asm/proto.h>
  27 #include <asm/setup.h>
  28 #include <asm/sections.h>
  29 #include <asm/kdebug.h>
  30 #include <asm/trampoline.h>
  31
  32 struct e820map e820;
  33
  34 /*
  35  * PFN of last memory page.
  36  */
  37 unsigned long end_pfn;
  38
  39 /*
  40  * end_pfn only includes RAM, while max_pfn_mapped includes all e820 entries.
  41  * The direct mapping extends to max_pfn_mapped, so that we can directly access
  42  * apertures, ACPI and other tables without having to play with fixmaps.
  43  */
  44 unsigned long max_pfn_mapped;
  45
  46 /*
  47  * Last pfn which the user wants to use.
  48  */
  49 static unsigned long __initdata end_user_pfn = MAXMEM>>PAGE_SHIFT;
  50
  51 /*
  52  * Early reserved memory areas.
  53  */
  54 #define MAX_EARLY_RES 20
  55
  56 struct early_res {
  57         unsigned long start, end;
  58         char name[16];
  59 };
  60 static struct early_res early_res[MAX_EARLY_RES] __initdata = {
  61         { 0, PAGE_SIZE, "BIOS data page" },                     /* BIOS data page */
  62 #ifdef CONFIG_X86_TRAMPOLINE
  63         { TRAMPOLINE_BASE, TRAMPOLINE_BASE + 2 * PAGE_SIZE, "TRAMPOLINE" },
  64 #endif
  65         {}
  66 };
  67
  68 void __init reserve_early(unsigned long start, unsigned long end, char *name)
  69 {
  70         int i;
  71         struct early_res *r;
  72         for (i = 0; i < MAX_EARLY_RES && early_res[i].end; i++) {
  73                 r = &early_res[i];
  74                 if (end > r->start && start < r->end)
  75                         panic("Overlapping early reservations %lx-%lx %s to %lx-%lx %s\n",
  76                               start, end - 1, name?name:"", r->start, r->end - 1, r->name);
  77         }
  78         if (i >= MAX_EARLY_RES)
  79                 panic("Too many early reservations");
  80         r = &early_res[i];
  81         r->start = start;
  82         r->end = end;
  83         if (name)
  84                 strncpy(r->name, name, sizeof(r->name) - 1);
  85 }
  86
  87 void __init free_early(unsigned long start, unsigned long end)
  88 {
  89         struct early_res *r;
  90         int i, j;
  91
  92         for (i = 0; i < MAX_EARLY_RES && early_res[i].end; i++) {
  93                 r = &early_res[i];
  94                 if (start == r->start && end == r->end)
  95                         break;
  96         }
  97         if (i >= MAX_EARLY_RES || !early_res[i].end)
  98                 panic("free_early on not reserved area: %lx-%lx!", start, end);
  99
 100         for (j = i + 1; j < MAX_EARLY_RES && early_res[j].end; j++)
 101                 ;
 102
 103         memmove(&early_res[i], &early_res[i + 1],
 104                (j - 1 - i) * sizeof(struct early_res));
 105
 106         early_res[j - 1].end = 0;
 107 }
 108
 109 void __init early_res_to_bootmem(unsigned long start, unsigned long end)
 110 {
 111         int i;
 112         unsigned long final_start, final_end;
 113         for (i = 0; i < MAX_EARLY_RES && early_res[i].end; i++) {
 114                 struct early_res *r = &early_res[i];
 115                 final_start = max(start, r->start);
 116                 final_end = min(end, r->end);
 117                 if (final_start >= final_end)
 118                         continue;
 119                 printk(KERN_INFO "  early res: %d [%lx-%lx] %s\n", i,
 120                         final_start, final_end - 1, r->name);
 121                 reserve_bootmem_generic(final_start, final_end - final_start);
 122         }
 123 }
 124
 125 /* Check for already reserved areas */
 126 static inline int __init
 127 bad_addr(unsigned long *addrp, unsigned long size, unsigned long align)
 128 {
 129         int i;
 130         unsigned long addr = *addrp, last;
 131         int changed = 0;
 132 again:
 133         last = addr + size;
 134         for (i = 0; i < MAX_EARLY_RES && early_res[i].end; i++) {
 135                 struct early_res *r = &early_res[i];
 136                 if (last >= r->start && addr < r->end) {
 137                         *addrp = addr = round_up(r->end, align);
 138                         changed = 1;
 139                         goto again;
 140                 }
 141         }
 142         return changed;
 143 }
 144
 145 /* Check for already reserved areas */
 146 static inline int __init
 147 bad_addr_size(unsigned long *addrp, unsigned long *sizep, unsigned long align)
 148 {
 149         int i;
 150         unsigned long addr = *addrp, last;
 151         unsigned long size = *sizep;
 152         int changed = 0;
 153 again:
 154         last = addr + size;
 155         for (i = 0; i < MAX_EARLY_RES && early_res[i].end; i++) {
 156                 struct early_res *r = &early_res[i];
 157                 if (last > r->start && addr < r->start) {
 158                         size = r->start - addr;
 159                         changed = 1;
 160                         goto again;
 161                 }
 162                 if (last > r->end && addr < r->end) {
 163                         addr = round_up(r->end, align);
 164                         size = last - addr;
 165                         changed = 1;
 166                         goto again;
 167                 }
 168                 if (last <= r->end && addr >= r->start) {
 169                         (*sizep)++;
 170                         return 0;
 171                 }
 172         }
 173         if (changed) {
 174                 *addrp = addr;
 175                 *sizep = size;
 176         }
 177         return changed;
 178 }
 179 /*
 180  * This function checks if any part of the range <start,end> is mapped
 181  * with type.
 182  */
 183 int
 184 e820_any_mapped(unsigned long start, unsigned long end, unsigned type)
 185 {
 186         int i;
 187
 188         for (i = 0; i < e820.nr_map; i++) {
 189                 struct e820entry *ei = &e820.map[i];
 190
 191                 if (type && ei->type != type)
 192                         continue;
 193                 if (ei->addr >= end || ei->addr + ei->size <= start)
 194                         continue;
 195                 return 1;
 196         }
 197         return 0;
 198 }
 199 EXPORT_SYMBOL_GPL(e820_any_mapped);
 200
 201 /*
 202  * This function checks if the entire range <start,end> is mapped with type.
 203  *
 204  * Note: this function only works correct if the e820 table is sorted and
 205  * not-overlapping, which is the case
 206  */
 207 int __init e820_all_mapped(unsigned long start, unsigned long end,
 208                            unsigned type)
 209 {
 210         int i;
 211
 212         for (i = 0; i < e820.nr_map; i++) {
 213                 struct e820entry *ei = &e820.map[i];
 214
 215                 if (type && ei->type != type)
 216                         continue;
 217                 /* is the region (part) in overlap with the current region ?*/
 218                 if (ei->addr >= end || ei->addr + ei->size <= start)
 219                         continue;
 220
 221                 /* if the region is at the beginning of <start,end> we move
 222                  * start to the end of the region since it's ok until there
 223                  */
 224                 if (ei->addr <= start)
 225                         start = ei->addr + ei->size;
 226                 /*
 227                  * if start is now at or beyond end, we're done, full
 228                  * coverage
 229                  */
 230                 if (start >= end)
 231                         return 1;
 232         }
 233         return 0;
 234 }
 235
 236 /*
 237  * Find a free area with specified alignment in a specific range.
 238  */
 239 unsigned long __init find_e820_area(unsigned long start, unsigned long end,
 240                                     unsigned long size, unsigned long align)
 241 {
 242         int i;
 243
 244         for (i = 0; i < e820.nr_map; i++) {
 245                 struct e820entry *ei = &e820.map[i];
 246                 unsigned long addr, last;
 247                 unsigned long ei_last;
 248
 249                 if (ei->type != E820_RAM)
 250                         continue;
 251                 addr = round_up(ei->addr, align);
 252                 ei_last = ei->addr + ei->size;
 253                 if (addr < start)
 254                         addr = round_up(start, align);
 255                 if (addr >= ei_last)
 256                         continue;
 257                 while (bad_addr(&addr, size, align) && addr+size <= ei_last)
 258                         ;
 259                 last = addr + size;
 260                 if (last > ei_last)
 261                         continue;
 262                 if (last > end)
 263                         continue;
 264                 return addr;
 265         }
 266         return -1UL;
 267 }
 268
 269 /*
 270  * Find next free range after *start
 271  */
 272 unsigned long __init find_e820_area_size(unsigned long start,
 273                                          unsigned long *sizep,
 274                                          unsigned long align)
 275 {
 276         int i;
 277
 278         for (i = 0; i < e820.nr_map; i++) {
 279                 struct e820entry *ei = &e820.map[i];
 280                 unsigned long addr, last;
 281                 unsigned long ei_last;
 282
 283                 if (ei->type != E820_RAM)
 284                         continue;
 285                 addr = round_up(ei->addr, align);
 286                 ei_last = ei->addr + ei->size;
 287                 if (addr < start)
 288                         addr = round_up(start, align);
 289                 if (addr >= ei_last)
 290                         continue;
 291                 *sizep = ei_last - addr;
 292                 while (bad_addr_size(&addr, sizep, align) &&
 293                         addr + *sizep <= ei_last)
 294                         ;
 295                 last = addr + *sizep;
 296                 if (last > ei_last)
 297                         continue;
 298                 return addr;
 299         }
 300         return -1UL;
 301
 302 }
 303 /*
 304  * Find the highest page frame number we have available
 305  */
 306 unsigned long __init e820_end_of_ram(void)
 307 {
 308         unsigned long end_pfn;
 309
 310         end_pfn = find_max_pfn_with_active_regions();
 311
 312         if (end_pfn > max_pfn_mapped)
 313                 max_pfn_mapped = end_pfn;
 314         if (max_pfn_mapped > MAXMEM>>PAGE_SHIFT)
 315                 max_pfn_mapped = MAXMEM>>PAGE_SHIFT;
 316         if (end_pfn > end_user_pfn)
 317                 end_pfn = end_user_pfn;
 318         if (end_pfn > max_pfn_mapped)
 319                 end_pfn = max_pfn_mapped;
 320
 321         printk(KERN_INFO "max_pfn_mapped = %lu\n", max_pfn_mapped);
 322         return end_pfn;
 323 }
 324
 325 /*
 326  * Mark e820 reserved areas as busy for the resource manager.
 327  */
 328 void __init e820_reserve_resources(void)
 329 {
 330         int i;
 331         struct resource *res;
 332
 333         res = alloc_bootmem_low(sizeof(struct resource) * e820.nr_map);
 334         for (i = 0; i < e820.nr_map; i++) {
 335                 switch (e820.map[i].type) {
 336                 case E820_RAM:  res->name = "System RAM"; break;
 337                 case E820_ACPI: res->name = "ACPI Tables"; break;
 338                 case E820_NVS:  res->name = "ACPI Non-volatile Storage"; break;
 339                 default:        res->name = "reserved";
 340                 }
 341                 res->start = e820.map[i].addr;
 342                 res->end = res->start + e820.map[i].size - 1;
 343                 res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
 344                 insert_resource(&iomem_resource, res);
 345                 res++;
 346         }
 347 }
 348
 349 /*
 350  * Find the ranges of physical addresses that do not correspond to
 351  * e820 RAM areas and mark the corresponding pages as nosave for software
 352  * suspend and suspend to RAM.
 353  *
 354  * This function requires the e820 map to be sorted and without any
 355  * overlapping entries and assumes the first e820 area to be RAM.
 356  */
 357 void __init e820_mark_nosave_regions(void)
 358 {
 359         int i;
 360         unsigned long paddr;
 361
 362         paddr = round_down(e820.map[0].addr + e820.map[0].size, PAGE_SIZE);
 363         for (i = 1; i < e820.nr_map; i++) {
 364                 struct e820entry *ei = &e820.map[i];
 365
 366                 if (paddr < ei->addr)
 367                         register_nosave_region(PFN_DOWN(paddr),
 368                                                 PFN_UP(ei->addr));
 369
 370                 paddr = round_down(ei->addr + ei->size, PAGE_SIZE);
 371                 if (ei->type != E820_RAM)
 372                         register_nosave_region(PFN_UP(ei->addr),
 373                                                 PFN_DOWN(paddr));
 374
 375                 if (paddr >= (end_pfn << PAGE_SHIFT))
 376                         break;
 377         }
 378 }
 379
 380 /*
 381  * Finds an active region in the address range from start_pfn to end_pfn and
 382  * returns its range in ei_startpfn and ei_endpfn for the e820 entry.
 383  */
 384 static int __init e820_find_active_region(const struct e820entry *ei,
 385                                           unsigned long start_pfn,
 386                                           unsigned long end_pfn,
 387                                           unsigned long *ei_startpfn,
 388                                           unsigned long *ei_endpfn)
 389 {
 390         *ei_startpfn = round_up(ei->addr, PAGE_SIZE) >> PAGE_SHIFT;
 391         *ei_endpfn = round_down(ei->addr + ei->size, PAGE_SIZE) >> PAGE_SHIFT;
 392
 393         /* Skip map entries smaller than a page */
 394         if (*ei_startpfn >= *ei_endpfn)
 395                 return 0;
 396
 397         /* Check if max_pfn_mapped should be updated */
 398         if (ei->type != E820_RAM && *ei_endpfn > max_pfn_mapped)
 399                 max_pfn_mapped = *ei_endpfn;
 400
 401         /* Skip if map is outside the node */
 402         if (ei->type != E820_RAM || *ei_endpfn <= start_pfn ||
 403                                     *ei_startpfn >= end_pfn)
 404                 return 0;
 405
 406         /* Check for overlaps */
 407         if (*ei_startpfn < start_pfn)
 408                 *ei_startpfn = start_pfn;
 409         if (*ei_endpfn > end_pfn)
 410                 *ei_endpfn = end_pfn;
 411
 412         /* Obey end_user_pfn to save on memmap */
 413         if (*ei_startpfn >= end_user_pfn)
 414                 return 0;
 415         if (*ei_endpfn > end_user_pfn)
 416                 *ei_endpfn = end_user_pfn;
 417
 418         return 1;
 419 }
 420
 421 /* Walk the e820 map and register active regions within a node */
 422 void __init
 423 e820_register_active_regions(int nid, unsigned long start_pfn,
 424                                                         unsigned long end_pfn)
 425 {
 426         unsigned long ei_startpfn;
 427         unsigned long ei_endpfn;
 428         int i;
 429
 430         for (i = 0; i < e820.nr_map; i++)
 431                 if (e820_find_active_region(&e820.map[i],
 432                                             start_pfn, end_pfn,
 433                                             &ei_startpfn, &ei_endpfn))
 434                         add_active_range(nid, ei_startpfn, ei_endpfn);
 435 }
 436
 437 /*
 438  * Add a memory region to the kernel e820 map.
 439  */
 440 void __init add_memory_region(unsigned long start, unsigned long size, int type)
 441 {
 442         int x = e820.nr_map;
 443
 444         if (x == E820MAX) {
 445                 printk(KERN_ERR "Ooops! Too many entries in the memory map!\n");
 446                 return;
 447         }
 448
 449         e820.map[x].addr = start;
 450         e820.map[x].size = size;
 451         e820.map[x].type = type;
 452         e820.nr_map++;
 453 }
 454
 455 /*
 456  * Find the hole size (in bytes) in the memory range.
 457  * @start: starting address of the memory range to scan
 458  * @end: ending address of the memory range to scan
 459  */
 460 unsigned long __init e820_hole_size(unsigned long start, unsigned long end)
 461 {
 462         unsigned long start_pfn = start >> PAGE_SHIFT;
 463         unsigned long end_pfn = end >> PAGE_SHIFT;
 464         unsigned long ei_startpfn, ei_endpfn, ram = 0;
 465         int i;
 466
 467         for (i = 0; i < e820.nr_map; i++) {
 468                 if (e820_find_active_region(&e820.map[i],
 469                                             start_pfn, end_pfn,
 470                                             &ei_startpfn, &ei_endpfn))
 471                         ram += ei_endpfn - ei_startpfn;
 472         }
 473         return end - start - (ram << PAGE_SHIFT);
 474 }
 475
 476 static void __init e820_print_map(char *who)
 477 {
 478         int i;
 479
 480         for (i = 0; i < e820.nr_map; i++) {
 481                 printk(KERN_INFO " %s: %016Lx - %016Lx ", who,
 482                        (unsigned long long) e820.map[i].addr,
 483                        (unsigned long long)
 484                        (e820.map[i].addr + e820.map[i].size));
 485                 switch (e820.map[i].type) {
 486                 case E820_RAM:
 487                         printk(KERN_CONT "(usable)\n");
 488                         break;
 489                 case E820_RESERVED:
 490                         printk(KERN_CONT "(reserved)\n");
 491                         break;
 492                 case E820_ACPI:
 493                         printk(KERN_CONT "(ACPI data)\n");
 494                         break;
 495                 case E820_NVS:
 496                         printk(KERN_CONT "(ACPI NVS)\n");
 497                         break;
 498                 default:
 499                         printk(KERN_CONT "type %u\n", e820.map[i].type);
 500                         break;
 501                 }
 502         }
 503 }
 504
 505 /*
 506  * Sanitize the BIOS e820 map.
 507  *
 508  * Some e820 responses include overlapping entries. The following
 509  * replaces the original e820 map with a new one, removing overlaps.
 510  *
 511  */
 512 static int __init sanitize_e820_map(struct e820entry *biosmap, char *pnr_map)
 513 {
 514         struct change_member {
 515                 struct e820entry *pbios; /* pointer to original bios entry */
 516                 unsigned long long addr; /* address for this change point */
 517         };
 518         static struct change_member change_point_list[2*E820MAX] __initdata;
 519         static struct change_member *change_point[2*E820MAX] __initdata;
 520         static struct e820entry *overlap_list[E820MAX] __initdata;
 521         static struct e820entry new_bios[E820MAX] __initdata;
 522         struct change_member *change_tmp;
 523         unsigned long current_type, last_type;
 524         unsigned long long last_addr;
 525         int chgidx, still_changing;
 526         int overlap_entries;
 527         int new_bios_entry;
 528         int old_nr, new_nr, chg_nr;
 529         int i;
 530
 531         /*
 532                 Visually we're performing the following
 533                 (1,2,3,4 = memory types)...
 534
 535                 Sample memory map (w/overlaps):
 536                    ____22__________________
 537                    ______________________4_
 538                    ____1111________________
 539                    _44_____________________
 540                    11111111________________
 541                    ____________________33__
 542                    ___________44___________
 543                    __________33333_________
 544                    ______________22________
 545                    ___________________2222_
 546                    _________111111111______
 547                    _____________________11_
 548                    _________________4______
 549
 550                 Sanitized equivalent (no overlap):
 551                    1_______________________
 552                    _44_____________________
 553                    ___1____________________
 554                    ____22__________________
 555                    ______11________________
 556                    _________1______________
 557                    __________3_____________
 558                    ___________44___________
 559                    _____________33_________
 560                    _______________2________
 561                    ________________1_______
 562                    _________________4______
 563                    ___________________2____
 564                    ____________________33__
 565                    ______________________4_
 566         */
 567
 568         /* if there's only one memory region, don't bother */
 569         if (*pnr_map < 2)
 570                 return -1;
 571
 572         old_nr = *pnr_map;
 573
 574         /* bail out if we find any unreasonable addresses in bios map */
 575         for (i = 0; i < old_nr; i++)
 576                 if (biosmap[i].addr + biosmap[i].size < biosmap[i].addr)
 577                         return -1;
 578
 579         /* create pointers for initial change-point information (for sorting) */
 580         for (i = 0; i < 2 * old_nr; i++)
 581                 change_point[i] = &change_point_list[i];
 582
 583         /* record all known change-points (starting and ending addresses),
 584            omitting those that are for empty memory regions */
 585         chgidx = 0;
 586         for (i = 0; i < old_nr; i++)    {
 587                 if (biosmap[i].size != 0) {
 588                         change_point[chgidx]->addr = biosmap[i].addr;
 589                         change_point[chgidx++]->pbios = &biosmap[i];
 590                         change_point[chgidx]->addr = biosmap[i].addr +
 591                                 biosmap[i].size;
 592                         change_point[chgidx++]->pbios = &biosmap[i];
 593                 }
 594         }
 595         chg_nr = chgidx;
 596
 597         /* sort change-point list by memory addresses (low -> high) */
 598         still_changing = 1;
 599         while (still_changing)  {
 600                 still_changing = 0;
 601                 for (i = 1; i < chg_nr; i++)  {
 602                         unsigned long long curaddr, lastaddr;
 603                         unsigned long long curpbaddr, lastpbaddr;
 604
 605                         curaddr = change_point[i]->addr;
 606                         lastaddr = change_point[i - 1]->addr;
 607                         curpbaddr = change_point[i]->pbios->addr;
 608                         lastpbaddr = change_point[i - 1]->pbios->addr;
 609
 610                         /*
 611                          * swap entries, when:
 612                          *
 613                          * curaddr > lastaddr or
 614                          * curaddr == lastaddr and curaddr == curpbaddr and
 615                          * lastaddr != lastpbaddr
 616                          */
 617                         if (curaddr < lastaddr ||
 618                             (curaddr == lastaddr && curaddr == curpbaddr &&
 619                              lastaddr != lastpbaddr)) {
 620                                 change_tmp = change_point[i];
 621                                 change_point[i] = change_point[i-1];
 622                                 change_point[i-1] = change_tmp;
 623                                 still_changing = 1;
 624                         }
 625                 }
 626         }
 627
 628         /* create a new bios memory map, removing overlaps */
 629         overlap_entries = 0;     /* number of entries in the overlap table */
 630         new_bios_entry = 0;      /* index for creating new bios map entries */
 631         last_type = 0;           /* start with undefined memory type */
 632         last_addr = 0;           /* start with 0 as last starting address */
 633
 634         /* loop through change-points, determining affect on the new bios map */
 635         for (chgidx = 0; chgidx < chg_nr; chgidx++) {
 636                 /* keep track of all overlapping bios entries */
 637                 if (change_point[chgidx]->addr ==
 638                     change_point[chgidx]->pbios->addr) {
 639                         /*
 640                          * add map entry to overlap list (> 1 entry
 641                          * implies an overlap)
 642                          */
 643                         overlap_list[overlap_entries++] =
 644                                 change_point[chgidx]->pbios;
 645                 } else {
 646                         /*
 647                          * remove entry from list (order independent,
 648                          * so swap with last)
 649                          */
 650                         for (i = 0; i < overlap_entries; i++) {
 651                                 if (overlap_list[i] ==
 652                                     change_point[chgidx]->pbios)
 653                                         overlap_list[i] =
 654                                                 overlap_list[overlap_entries-1];
 655                         }
 656                         overlap_entries--;
 657                 }
 658                 /*
 659                  * if there are overlapping entries, decide which
 660                  * "type" to use (larger value takes precedence --
 661                  * 1=usable, 2,3,4,4+=unusable)
 662                  */
 663                 current_type = 0;
 664                 for (i = 0; i < overlap_entries; i++)
 665                         if (overlap_list[i]->type > current_type)
 666                                 current_type = overlap_list[i]->type;
 667                 /*
 668                  * continue building up new bios map based on this
 669                  * information
 670                  */
 671                 if (current_type != last_type)  {
 672                         if (last_type != 0)      {
 673                                 new_bios[new_bios_entry].size =
 674                                         change_point[chgidx]->addr - last_addr;
 675                                 /*
 676                                  * move forward only if the new size
 677                                  * was non-zero
 678                                  */
 679                                 if (new_bios[new_bios_entry].size != 0)
 680                                         /*
 681                                          * no more space left for new
 682                                          * bios entries ?
 683                                          */
 684                                         if (++new_bios_entry >= E820MAX)
 685                                                 break;
 686                         }
 687                         if (current_type != 0)  {
 688                                 new_bios[new_bios_entry].addr =
 689                                         change_point[chgidx]->addr;
 690                                 new_bios[new_bios_entry].type = current_type;
 691                                 last_addr = change_point[chgidx]->addr;
 692                         }
 693                         last_type = current_type;
 694                 }
 695         }
 696         /* retain count for new bios entries */
 697         new_nr = new_bios_entry;
 698
 699         /* copy new bios mapping into original location */
 700         memcpy(biosmap, new_bios, new_nr * sizeof(struct e820entry));
 701         *pnr_map = new_nr;
 702
 703         return 0;
 704 }
 705
 706 /*
 707  * Copy the BIOS e820 map into a safe place.
 708  *
 709  * Sanity-check it while we're at it..
 710  *
 711  * If we're lucky and live on a modern system, the setup code
 712  * will have given us a memory map that we can use to properly
 713  * set up memory.  If we aren't, we'll fake a memory map.
 714  */
 715 static int __init copy_e820_map(struct e820entry *biosmap, int nr_map)
 716 {
 717         /* Only one memory region (or negative)? Ignore it */
 718         if (nr_map < 2)
 719                 return -1;
 720
 721         do {
 722                 u64 start = biosmap->addr;
 723                 u64 size = biosmap->size;
 724                 u64 end = start + size;
 725                 u32 type = biosmap->type;
 726
 727                 /* Overflow in 64 bits? Ignore the memory map. */
 728                 if (start > end)
 729                         return -1;
 730
 731                 add_memory_region(start, size, type);
 732         } while (biosmap++, --nr_map);
 733         return 0;
 734 }
 735
 736 static void early_panic(char *msg)
 737 {
 738         early_printk(msg);
 739         panic(msg);
 740 }
 741
 742 /* We're not void only for x86 32-bit compat */
 743 char * __init machine_specific_memory_setup(void)
 744 {
 745         char *who = "BIOS-e820";
 746         /*
 747          * Try to copy the BIOS-supplied E820-map.
 748          *
 749          * Otherwise fake a memory map; one section from 0k->640k,
 750          * the next section from 1mb->appropriate_mem_k
 751          */
 752         sanitize_e820_map(boot_params.e820_map, &boot_params.e820_entries);
 753         if (copy_e820_map(boot_params.e820_map, boot_params.e820_entries) < 0)
 754                 early_panic("Cannot find a valid memory map");
 755         printk(KERN_INFO "BIOS-provided physical RAM map:\n");
 756         e820_print_map(who);
 757
 758         /* In case someone cares... */
 759         return who;
 760 }
 761
 762 static int __init parse_memopt(char *p)
 763 {
 764         if (!p)
 765                 return -EINVAL;
 766         end_user_pfn = memparse(p, &p);
 767         end_user_pfn >>= PAGE_SHIFT;
 768         return 0;
 769 }
 770 early_param("mem", parse_memopt);
 771
 772 static int userdef __initdata;
 773
 774 static int __init parse_memmap_opt(char *p)
 775 {
 776         char *oldp;
 777         unsigned long long start_at, mem_size;
 778
 779         if (!strcmp(p, "exactmap")) {
 780 #ifdef CONFIG_CRASH_DUMP
 781                 /*
 782                  * If we are doing a crash dump, we still need to know
 783                  * the real mem size before original memory map is
 784                  * reset.
 785                  */
 786                 e820_register_active_regions(0, 0, -1UL);
 787                 saved_max_pfn = e820_end_of_ram();
 788                 remove_all_active_ranges();
 789 #endif
 790                 max_pfn_mapped = 0;
 791                 e820.nr_map = 0;
 792                 userdef = 1;
 793                 return 0;
 794         }
 795
 796         oldp = p;
 797         mem_size = memparse(p, &p);
 798         if (p == oldp)
 799                 return -EINVAL;
 800
 801         userdef = 1;
 802         if (*p == '@') {
 803                 start_at = memparse(p+1, &p);
 804                 add_memory_region(start_at, mem_size, E820_RAM);
 805         } else if (*p == '#') {
 806                 start_at = memparse(p+1, &p);
 807                 add_memory_region(start_at, mem_size, E820_ACPI);
 808         } else if (*p == '$') {
 809                 start_at = memparse(p+1, &p);
 810                 add_memory_region(start_at, mem_size, E820_RESERVED);
 811         } else {
 812                 end_user_pfn = (mem_size >> PAGE_SHIFT);
 813         }
 814         return *p == '\0' ? 0 : -EINVAL;
 815 }
 816 early_param("memmap", parse_memmap_opt);
 817
 818 void __init finish_e820_parsing(void)
 819 {
 820         if (userdef) {
 821                 char nr = e820.nr_map;
 822
 823                 if (sanitize_e820_map(e820.map, &nr) < 0)
 824                         early_panic("Invalid user supplied memory map");
 825                 e820.nr_map = nr;
 826
 827                 printk(KERN_INFO "user-defined physical RAM map:\n");
 828                 e820_print_map("user");
 829         }
 830 }
 831
 832 void __init update_memory_range(u64 start, u64 size, unsigned old_type,
 833                                 unsigned new_type)
 834 {
 835         int i;
 836
 837         BUG_ON(old_type == new_type);
 838
 839         for (i = 0; i < e820.nr_map; i++) {
 840                 struct e820entry *ei = &e820.map[i];
 841                 u64 final_start, final_end;
 842                 if (ei->type != old_type)
 843                         continue;
 844                 /* totally covered? */
 845                 if (ei->addr >= start && ei->size <= size) {
 846                         ei->type = new_type;
 847                         continue;
 848                 }
 849                 /* partially covered */
 850                 final_start = max(start, ei->addr);
 851                 final_end = min(start + size, ei->addr + ei->size);
 852                 if (final_start >= final_end)
 853                         continue;
 854                 add_memory_region(final_start, final_end - final_start,
 855                                          new_type);
 856         }
 857 }
 858
 859 void __init update_e820(void)
 860 {
 861         u8 nr_map;
 862
 863         nr_map = e820.nr_map;
 864         if (sanitize_e820_map(e820.map, &nr_map))
 865                 return;
 866         e820.nr_map = nr_map;
 867         printk(KERN_INFO "modified physical RAM map:\n");
 868         e820_print_map("modified");
 869 }
 870
 871 unsigned long pci_mem_start = 0xaeedbabe;
 872 EXPORT_SYMBOL(pci_mem_start);
 873
 874 /*
 875  * Search for the biggest gap in the low 32 bits of the e820
 876  * memory space.  We pass this space to PCI to assign MMIO resources
 877  * for hotplug or unconfigured devices in.
 878  * Hopefully the BIOS let enough space left.
 879  */
 880 __init void e820_setup_gap(void)
 881 {
 882         unsigned long gapstart, gapsize, round;
 883         unsigned long last;
 884         int i;
 885         int found = 0;
 886
 887         last = 0x100000000ull;
 888         gapstart = 0x10000000;
 889         gapsize = 0x400000;
 890         i = e820.nr_map;
 891         while (--i >= 0) {
 892                 unsigned long long start = e820.map[i].addr;
 893                 unsigned long long end = start + e820.map[i].size;
 894
 895                 /*
 896                  * Since "last" is at most 4GB, we know we'll
 897                  * fit in 32 bits if this condition is true
 898                  */
 899                 if (last > end) {
 900                         unsigned long gap = last - end;
 901
 902                         if (gap > gapsize) {
 903                                 gapsize = gap;
 904                                 gapstart = end;
 905                                 found = 1;
 906                         }
 907                 }
 908                 if (start < last)
 909                         last = start;
 910         }
 911
 912         if (!found) {
 913                 gapstart = (end_pfn << PAGE_SHIFT) + 1024*1024;
 914                 printk(KERN_ERR "PCI: Warning: Cannot find a gap in the 32bit "
 915                        "address range\n"
 916                        KERN_ERR "PCI: Unassigned devices with 32bit resource "
 917                        "registers may break!\n");
 918         }
 919
 920         /*
 921          * See how much we want to round up: start off with
 922          * rounding to the next 1MB area.
 923          */
 924         round = 0x100000;
 925         while ((gapsize >> 4) > round)
 926                 round += round;
 927         /* Fun with two's complement */
 928         pci_mem_start = (gapstart + round) & -round;
 929
 930         printk(KERN_INFO
 931                "Allocating PCI resources starting at %lx (gap: %lx:%lx)\n",
 932                pci_mem_start, gapstart, gapsize);
 933 }
 934
 935 int __init arch_get_ram_range(int slot, u64 *addr, u64 *size)
 936 {
 937         int i;
 938
 939         if (slot < 0 || slot >= e820.nr_map)
 940                 return -1;
 941         for (i = slot; i < e820.nr_map; i++) {
 942                 if (e820.map[i].type != E820_RAM)
 943                         continue;
 944                 break;
 945         }
 946         if (i == e820.nr_map || e820.map[i].addr > (max_pfn << PAGE_SHIFT))
 947                 return -1;
 948         *addr = e820.map[i].addr;
 949         *size = min_t(u64, e820.map[i].size + e820.map[i].addr,
 950                 max_pfn << PAGE_SHIFT) - *addr;
 951         return i + 1;
 952 }