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