arch/x86_64/kernel/e820.c

   1 /*
   2  * Handle the memory map.
   3  * The functions here do the job until bootmem takes over.
   4  * $Id: e820.c,v 1.4 2002/09/19 19:25:32 ak Exp $
   5  *
   6  *  Getting sanitize_e820_map() in sync with i386 version by applying change:
   7  *  -  Provisions for empty E820 memory regions (reported by certain BIOSes).
   8  *     Alex Achenbach <xela@slit.de>, December 2002.
   9  *  Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
  10  *
  11  */
  12 #include <linux/config.h>
  13 #include <linux/kernel.h>
  14 #include <linux/types.h>
  15 #include <linux/init.h>
  16 #include <linux/bootmem.h>
  17 #include <linux/ioport.h>
  18 #include <linux/string.h>
  19 #include <linux/kexec.h>
  20 #include <asm/page.h>
  21 #include <asm/e820.h>
  22 #include <asm/proto.h>
  23 #include <asm/bootsetup.h>
  24
  25 extern char _end[];
  26
  27 /*
  28  * PFN of last memory page.
  29  */
  30 unsigned long end_pfn;
  31 EXPORT_SYMBOL(end_pfn);
  32
  33 /*
  34  * end_pfn only includes RAM, while end_pfn_map includes all e820 entries.
  35  * The direct mapping extends to end_pfn_map, so that we can directly access
  36  * apertures, ACPI and other tables without having to play with fixmaps.
  37  */
  38 unsigned long end_pfn_map;
  39
  40 /*
  41  * Last pfn which the user wants to use.
  42  */
  43 unsigned long end_user_pfn = MAXMEM>>PAGE_SHIFT;
  44
  45 extern struct resource code_resource, data_resource;
  46
  47 /* Check for some hardcoded bad areas that early boot is not allowed to touch */
  48 static inline int bad_addr(unsigned long *addrp, unsigned long size)
  49 {
  50         unsigned long addr = *addrp, last = addr + size;
  51
  52         /* various gunk below that needed for SMP startup */
  53         if (addr < 0x8000) {
  54                 *addrp = 0x8000;
  55                 return 1;
  56         }
  57
  58         /* direct mapping tables of the kernel */
  59         if (last >= table_start<<PAGE_SHIFT && addr < table_end<<PAGE_SHIFT) {
  60                 *addrp = table_end << PAGE_SHIFT;
  61                 return 1;
  62         }
  63
  64         /* initrd */
  65 #ifdef CONFIG_BLK_DEV_INITRD
  66         if (LOADER_TYPE && INITRD_START && last >= INITRD_START &&
  67             addr < INITRD_START+INITRD_SIZE) {
  68                 *addrp = INITRD_START + INITRD_SIZE;
  69                 return 1;
  70         }
  71 #endif
  72         /* kernel code + 640k memory hole (later should not be needed, but
  73            be paranoid for now) */
  74         if (last >= 640*1024 && addr < __pa_symbol(&_end)) {
  75                 *addrp = __pa_symbol(&_end);
  76                 return 1;
  77         }
  78         /* XXX ramdisk image here? */
  79         return 0;
  80 }
  81
  82 int __init e820_mapped(unsigned long start, unsigned long end, unsigned type)
  83 {
  84         int i;
  85         for (i = 0; i < e820.nr_map; i++) {
  86                 struct e820entry *ei = &e820.map[i];
  87                 if (type && ei->type != type)
  88                         continue;
  89                 if (ei->addr >= end || ei->addr + ei->size <= start)
  90                         continue;
  91                 return 1;
  92         }
  93         return 0;
  94 }
  95
  96 /*
  97  * Find a free area in a specific range.
  98  */
  99 unsigned long __init find_e820_area(unsigned long start, unsigned long end, unsigned size)
 100 {
 101         int i;
 102         for (i = 0; i < e820.nr_map; i++) {
 103                 struct e820entry *ei = &e820.map[i];
 104                 unsigned long addr = ei->addr, last;
 105                 if (ei->type != E820_RAM)
 106                         continue;
 107                 if (addr < start)
 108                         addr = start;
 109                 if (addr > ei->addr + ei->size)
 110                         continue;
 111                 while (bad_addr(&addr, size) && addr+size < ei->addr + ei->size)
 112                         ;
 113                 last = addr + size;
 114                 if (last > ei->addr + ei->size)
 115                         continue;
 116                 if (last > end)
 117                         continue;
 118                 return addr;
 119         }
 120         return -1UL;
 121 }
 122
 123 /*
 124  * Free bootmem based on the e820 table for a node.
 125  */
 126 void __init e820_bootmem_free(pg_data_t *pgdat, unsigned long start,unsigned long end)
 127 {
 128         int i;
 129         for (i = 0; i < e820.nr_map; i++) {
 130                 struct e820entry *ei = &e820.map[i];
 131                 unsigned long last, addr;
 132
 133                 if (ei->type != E820_RAM ||
 134                     ei->addr+ei->size <= start ||
 135                     ei->addr >= end)
 136                         continue;
 137
 138                 addr = round_up(ei->addr, PAGE_SIZE);
 139                 if (addr < start)
 140                         addr = start;
 141
 142                 last = round_down(ei->addr + ei->size, PAGE_SIZE);
 143                 if (last >= end)
 144                         last = end;
 145
 146                 if (last > addr && last-addr >= PAGE_SIZE)
 147                         free_bootmem_node(pgdat, addr, last-addr);
 148         }
 149 }
 150
 151 /*
 152  * Find the highest page frame number we have available
 153  */
 154 unsigned long __init e820_end_of_ram(void)
 155 {
 156         int i;
 157         unsigned long end_pfn = 0;
 158
 159         for (i = 0; i < e820.nr_map; i++) {
 160                 struct e820entry *ei = &e820.map[i];
 161                 unsigned long start, end;
 162
 163                 start = round_up(ei->addr, PAGE_SIZE);
 164                 end = round_down(ei->addr + ei->size, PAGE_SIZE);
 165                 if (start >= end)
 166                         continue;
 167                 if (ei->type == E820_RAM) {
 168                 if (end > end_pfn<<PAGE_SHIFT)
 169                         end_pfn = end>>PAGE_SHIFT;
 170                 } else {
 171                         if (end > end_pfn_map<<PAGE_SHIFT)
 172                                 end_pfn_map = end>>PAGE_SHIFT;
 173                 }
 174         }
 175
 176         if (end_pfn > end_pfn_map)
 177                 end_pfn_map = end_pfn;
 178         if (end_pfn_map > MAXMEM>>PAGE_SHIFT)
 179                 end_pfn_map = MAXMEM>>PAGE_SHIFT;
 180         if (end_pfn > end_user_pfn)
 181                 end_pfn = end_user_pfn;
 182         if (end_pfn > end_pfn_map)
 183                 end_pfn = end_pfn_map;
 184
 185         return end_pfn;
 186 }
 187
 188 /*
 189  * Compute how much memory is missing in a range.
 190  * Unlike the other functions in this file the arguments are in page numbers.
 191  */
 192 unsigned long __init
 193 e820_hole_size(unsigned long start_pfn, unsigned long end_pfn)
 194 {
 195         unsigned long ram = 0;
 196         unsigned long start = start_pfn << PAGE_SHIFT;
 197         unsigned long end = end_pfn << PAGE_SHIFT;
 198         int i;
 199         for (i = 0; i < e820.nr_map; i++) {
 200                 struct e820entry *ei = &e820.map[i];
 201                 unsigned long last, addr;
 202
 203                 if (ei->type != E820_RAM ||
 204                     ei->addr+ei->size <= start ||
 205                     ei->addr >= end)
 206                         continue;
 207
 208                 addr = round_up(ei->addr, PAGE_SIZE);
 209                 if (addr < start)
 210                         addr = start;
 211
 212                 last = round_down(ei->addr + ei->size, PAGE_SIZE);
 213                 if (last >= end)
 214                         last = end;
 215
 216                 if (last > addr)
 217                         ram += last - addr;
 218         }
 219         return ((end - start) - ram) >> PAGE_SHIFT;
 220 }
 221
 222 /*
 223  * Mark e820 reserved areas as busy for the resource manager.
 224  */
 225 void __init e820_reserve_resources(void)
 226 {
 227         int i;
 228         for (i = 0; i < e820.nr_map; i++) {
 229                 struct resource *res;
 230                 res = alloc_bootmem_low(sizeof(struct resource));
 231                 switch (e820.map[i].type) {
 232                 case E820_RAM:  res->name = "System RAM"; break;
 233                 case E820_ACPI: res->name = "ACPI Tables"; break;
 234                 case E820_NVS:  res->name = "ACPI Non-volatile Storage"; break;
 235                 default:        res->name = "reserved";
 236                 }
 237                 res->start = e820.map[i].addr;
 238                 res->end = res->start + e820.map[i].size - 1;
 239                 res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
 240                 request_resource(&iomem_resource, res);
 241                 if (e820.map[i].type == E820_RAM) {
 242                         /*
 243                          *  We don't know which RAM region contains kernel data,
 244                          *  so we try it repeatedly and let the resource manager
 245                          *  test it.
 246                          */
 247                         request_resource(res, &code_resource);
 248                         request_resource(res, &data_resource);
 249 #ifdef CONFIG_KEXEC
 250                         request_resource(res, &crashk_res);
 251 #endif
 252                 }
 253         }
 254 }
 255
 256 /*
 257  * Add a memory region to the kernel e820 map.
 258  */
 259 void __init add_memory_region(unsigned long start, unsigned long size, int type)
 260 {
 261         int x = e820.nr_map;
 262
 263         if (x == E820MAX) {
 264                 printk(KERN_ERR "Ooops! Too many entries in the memory map!\n");
 265                 return;
 266         }
 267
 268         e820.map[x].addr = start;
 269         e820.map[x].size = size;
 270         e820.map[x].type = type;
 271         e820.nr_map++;
 272 }
 273
 274 void __init e820_print_map(char *who)
 275 {
 276         int i;
 277
 278         for (i = 0; i < e820.nr_map; i++) {
 279                 printk(" %s: %016Lx - %016Lx ", who,
 280                         (unsigned long long) e820.map[i].addr,
 281                         (unsigned long long) (e820.map[i].addr + e820.map[i].size));
 282                 switch (e820.map[i].type) {
 283                 case E820_RAM:  printk("(usable)\n");
 284                                 break;
 285                 case E820_RESERVED:
 286                                 printk("(reserved)\n");
 287                                 break;
 288                 case E820_ACPI:
 289                                 printk("(ACPI data)\n");
 290                                 break;
 291                 case E820_NVS:
 292                                 printk("(ACPI NVS)\n");
 293                                 break;
 294                 default:        printk("type %u\n", e820.map[i].type);
 295                                 break;
 296                 }
 297         }
 298 }
 299
 300 /*
 301  * Sanitize the BIOS e820 map.
 302  *
 303  * Some e820 responses include overlapping entries.  The following
 304  * replaces the original e820 map with a new one, removing overlaps.
 305  *
 306  */
 307 static int __init sanitize_e820_map(struct e820entry * biosmap, char * pnr_map)
 308 {
 309         struct change_member {
 310                 struct e820entry *pbios; /* pointer to original bios entry */
 311                 unsigned long long addr; /* address for this change point */
 312         };
 313         static struct change_member change_point_list[2*E820MAX] __initdata;
 314         static struct change_member *change_point[2*E820MAX] __initdata;
 315         static struct e820entry *overlap_list[E820MAX] __initdata;
 316         static struct e820entry new_bios[E820MAX] __initdata;
 317         struct change_member *change_tmp;
 318         unsigned long current_type, last_type;
 319         unsigned long long last_addr;
 320         int chgidx, still_changing;
 321         int overlap_entries;
 322         int new_bios_entry;
 323         int old_nr, new_nr, chg_nr;
 324         int i;
 325
 326         /*
 327                 Visually we're performing the following (1,2,3,4 = memory types)...
 328
 329                 Sample memory map (w/overlaps):
 330                    ____22__________________
 331                    ______________________4_
 332                    ____1111________________
 333                    _44_____________________
 334                    11111111________________
 335                    ____________________33__
 336                    ___________44___________
 337                    __________33333_________
 338                    ______________22________
 339                    ___________________2222_
 340                    _________111111111______
 341                    _____________________11_
 342                    _________________4______
 343
 344                 Sanitized equivalent (no overlap):
 345                    1_______________________
 346                    _44_____________________
 347                    ___1____________________
 348                    ____22__________________
 349                    ______11________________
 350                    _________1______________
 351                    __________3_____________
 352                    ___________44___________
 353                    _____________33_________
 354                    _______________2________
 355                    ________________1_______
 356                    _________________4______
 357                    ___________________2____
 358                    ____________________33__
 359                    ______________________4_
 360         */
 361
 362         /* if there's only one memory region, don't bother */
 363         if (*pnr_map < 2)
 364                 return -1;
 365
 366         old_nr = *pnr_map;
 367
 368         /* bail out if we find any unreasonable addresses in bios map */
 369         for (i=0; i<old_nr; i++)
 370                 if (biosmap[i].addr + biosmap[i].size < biosmap[i].addr)
 371                         return -1;
 372
 373         /* create pointers for initial change-point information (for sorting) */
 374         for (i=0; i < 2*old_nr; i++)
 375                 change_point[i] = &change_point_list[i];
 376
 377         /* record all known change-points (starting and ending addresses),
 378            omitting those that are for empty memory regions */
 379         chgidx = 0;
 380         for (i=0; i < old_nr; i++)      {
 381                 if (biosmap[i].size != 0) {
 382                         change_point[chgidx]->addr = biosmap[i].addr;
 383                         change_point[chgidx++]->pbios = &biosmap[i];
 384                         change_point[chgidx]->addr = biosmap[i].addr + biosmap[i].size;
 385                         change_point[chgidx++]->pbios = &biosmap[i];
 386                 }
 387         }
 388         chg_nr = chgidx;
 389
 390         /* sort change-point list by memory addresses (low -> high) */
 391         still_changing = 1;
 392         while (still_changing)  {
 393                 still_changing = 0;
 394                 for (i=1; i < chg_nr; i++)  {
 395                         /* if <current_addr> > <last_addr>, swap */
 396                         /* or, if current=<start_addr> & last=<end_addr>, swap */
 397                         if ((change_point[i]->addr < change_point[i-1]->addr) ||
 398                                 ((change_point[i]->addr == change_point[i-1]->addr) &&
 399                                  (change_point[i]->addr == change_point[i]->pbios->addr) &&
 400                                  (change_point[i-1]->addr != change_point[i-1]->pbios->addr))
 401                            )
 402                         {
 403                                 change_tmp = change_point[i];
 404                                 change_point[i] = change_point[i-1];
 405                                 change_point[i-1] = change_tmp;
 406                                 still_changing=1;
 407                         }
 408                 }
 409         }
 410
 411         /* create a new bios memory map, removing overlaps */
 412         overlap_entries=0;       /* number of entries in the overlap table */
 413         new_bios_entry=0;        /* index for creating new bios map entries */
 414         last_type = 0;           /* start with undefined memory type */
 415         last_addr = 0;           /* start with 0 as last starting address */
 416         /* loop through change-points, determining affect on the new bios map */
 417         for (chgidx=0; chgidx < chg_nr; chgidx++)
 418         {
 419                 /* keep track of all overlapping bios entries */
 420                 if (change_point[chgidx]->addr == change_point[chgidx]->pbios->addr)
 421                 {
 422                         /* add map entry to overlap list (> 1 entry implies an overlap) */
 423                         overlap_list[overlap_entries++]=change_point[chgidx]->pbios;
 424                 }
 425                 else
 426                 {
 427                         /* remove entry from list (order independent, so swap with last) */
 428                         for (i=0; i<overlap_entries; i++)
 429                         {
 430                                 if (overlap_list[i] == change_point[chgidx]->pbios)
 431                                         overlap_list[i] = overlap_list[overlap_entries-1];
 432                         }
 433                         overlap_entries--;
 434                 }
 435                 /* if there are overlapping entries, decide which "type" to use */
 436                 /* (larger value takes precedence -- 1=usable, 2,3,4,4+=unusable) */
 437                 current_type = 0;
 438                 for (i=0; i<overlap_entries; i++)
 439                         if (overlap_list[i]->type > current_type)
 440                                 current_type = overlap_list[i]->type;
 441                 /* continue building up new bios map based on this information */
 442                 if (current_type != last_type)  {
 443                         if (last_type != 0)      {
 444                                 new_bios[new_bios_entry].size =
 445                                         change_point[chgidx]->addr - last_addr;
 446                                 /* move forward only if the new size was non-zero */
 447                                 if (new_bios[new_bios_entry].size != 0)
 448                                         if (++new_bios_entry >= E820MAX)
 449                                                 break;  /* no more space left for new bios entries */
 450                         }
 451                         if (current_type != 0)  {
 452                                 new_bios[new_bios_entry].addr = change_point[chgidx]->addr;
 453                                 new_bios[new_bios_entry].type = current_type;
 454                                 last_addr=change_point[chgidx]->addr;
 455                         }
 456                         last_type = current_type;
 457                 }
 458         }
 459         new_nr = new_bios_entry;   /* retain count for new bios entries */
 460
 461         /* copy new bios mapping into original location */
 462         memcpy(biosmap, new_bios, new_nr*sizeof(struct e820entry));
 463         *pnr_map = new_nr;
 464
 465         return 0;
 466 }
 467
 468 /*
 469  * Copy the BIOS e820 map into a safe place.
 470  *
 471  * Sanity-check it while we're at it..
 472  *
 473  * If we're lucky and live on a modern system, the setup code
 474  * will have given us a memory map that we can use to properly
 475  * set up memory.  If we aren't, we'll fake a memory map.
 476  *
 477  * We check to see that the memory map contains at least 2 elements
 478  * before we'll use it, because the detection code in setup.S may
 479  * not be perfect and most every PC known to man has two memory
 480  * regions: one from 0 to 640k, and one from 1mb up.  (The IBM
 481  * thinkpad 560x, for example, does not cooperate with the memory
 482  * detection code.)
 483  */
 484 static int __init copy_e820_map(struct e820entry * biosmap, int nr_map)
 485 {
 486         /* Only one memory region (or negative)? Ignore it */
 487         if (nr_map < 2)
 488                 return -1;
 489
 490         do {
 491                 unsigned long start = biosmap->addr;
 492                 unsigned long size = biosmap->size;
 493                 unsigned long end = start + size;
 494                 unsigned long type = biosmap->type;
 495
 496                 /* Overflow in 64 bits? Ignore the memory map. */
 497                 if (start > end)
 498                         return -1;
 499
 500                 /*
 501                  * Some BIOSes claim RAM in the 640k - 1M region.
 502                  * Not right. Fix it up.
 503                  *
 504                  * This should be removed on Hammer which is supposed to not
 505                  * have non e820 covered ISA mappings there, but I had some strange
 506                  * problems so it stays for now.  -AK
 507                  */
 508                 if (type == E820_RAM) {
 509                         if (start < 0x100000ULL && end > 0xA0000ULL) {
 510                                 if (start < 0xA0000ULL)
 511                                         add_memory_region(start, 0xA0000ULL-start, type);
 512                                 if (end <= 0x100000ULL)
 513                                         continue;
 514                                 start = 0x100000ULL;
 515                                 size = end - start;
 516                         }
 517                 }
 518
 519                 add_memory_region(start, size, type);
 520         } while (biosmap++,--nr_map);
 521         return 0;
 522 }
 523
 524 void __init setup_memory_region(void)
 525 {
 526         char *who = "BIOS-e820";
 527
 528         /*
 529          * Try to copy the BIOS-supplied E820-map.
 530          *
 531          * Otherwise fake a memory map; one section from 0k->640k,
 532          * the next section from 1mb->appropriate_mem_k
 533          */
 534         sanitize_e820_map(E820_MAP, &E820_MAP_NR);
 535         if (copy_e820_map(E820_MAP, E820_MAP_NR) < 0) {
 536                 unsigned long mem_size;
 537
 538                 /* compare results from other methods and take the greater */
 539                 if (ALT_MEM_K < EXT_MEM_K) {
 540                         mem_size = EXT_MEM_K;
 541                         who = "BIOS-88";
 542                 } else {
 543                         mem_size = ALT_MEM_K;
 544                         who = "BIOS-e801";
 545                 }
 546
 547                 e820.nr_map = 0;
 548                 add_memory_region(0, LOWMEMSIZE(), E820_RAM);
 549                 add_memory_region(HIGH_MEMORY, mem_size << 10, E820_RAM);
 550         }
 551         printk(KERN_INFO "BIOS-provided physical RAM map:\n");
 552         e820_print_map(who);
 553 }
 554
 555 void __init parse_memopt(char *p, char **from)
 556 {
 557         end_user_pfn = memparse(p, from);
 558         end_user_pfn >>= PAGE_SHIFT;
 559 }
 560
 561 unsigned long pci_mem_start = 0xaeedbabe;
 562
 563 /*
 564  * Search for the biggest gap in the low 32 bits of the e820
 565  * memory space.  We pass this space to PCI to assign MMIO resources
 566  * for hotplug or unconfigured devices in.
 567  * Hopefully the BIOS let enough space left.
 568  */
 569 __init void e820_setup_gap(void)
 570 {
 571         unsigned long gapstart, gapsize, round;
 572         unsigned long last;
 573         int i;
 574         int found = 0;
 575
 576         last = 0x100000000ull;
 577         gapstart = 0x10000000;
 578         gapsize = 0x400000;
 579         i = e820.nr_map;
 580         while (--i >= 0) {
 581                 unsigned long long start = e820.map[i].addr;
 582                 unsigned long long end = start + e820.map[i].size;
 583
 584                 /*
 585                  * Since "last" is at most 4GB, we know we'll
 586                  * fit in 32 bits if this condition is true
 587                  */
 588                 if (last > end) {
 589                         unsigned long gap = last - end;
 590
 591                         if (gap > gapsize) {
 592                                 gapsize = gap;
 593                                 gapstart = end;
 594                                 found = 1;
 595                         }
 596                 }
 597                 if (start < last)
 598                         last = start;
 599         }
 600
 601         if (!found) {
 602                 gapstart = (end_pfn << PAGE_SHIFT) + 1024*1024;
 603                 printk(KERN_ERR "PCI: Warning: Cannot find a gap in the 32bit address range\n"
 604                        KERN_ERR "PCI: Unassigned devices with 32bit resource registers may break!\n");
 605         }
 606
 607         /*
 608          * See how much we want to round up: start off with
 609          * rounding to the next 1MB area.
 610          */
 611         round = 0x100000;
 612         while ((gapsize >> 4) > round)
 613                 round += round;
 614         /* Fun with two's complement */
 615         pci_mem_start = (gapstart + round) & -round;
 616
 617         printk(KERN_INFO "Allocating PCI resources starting at %lx (gap: %lx:%lx)\n",
 618                 pci_mem_start, gapstart, gapsize);
 619 }