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 #include <linux/config.h>
   7 #include <linux/kernel.h>
   8 #include <linux/types.h>
   9 #include <linux/init.h>
  10 #include <linux/bootmem.h>
  11 #include <linux/ioport.h>
  12 #include <linux/string.h>
  13 #include <asm/page.h>
  14 #include <asm/e820.h>
  15 #include <asm/proto.h>
  16 #include <asm/bootsetup.h>
  17
  18 extern char _end[];
  19
  20 /*
  21  * PFN of last memory page.
  22  */
  23 unsigned long end_pfn;
  24
  25 /*
  26  * end_pfn only includes RAM, while end_pfn_map includes all e820 entries.
  27  * The direct mapping extends to end_pfn_map, so that we can directly access
  28  * apertures, ACPI and other tables without having to play with fixmaps.
  29  */
  30 unsigned long end_pfn_map;
  31
  32 /*
  33  * Last pfn which the user wants to use.
  34  */
  35 unsigned long end_user_pfn = MAXMEM>>PAGE_SHIFT;
  36
  37 extern struct resource code_resource, data_resource;
  38
  39 /* Check for some hardcoded bad areas that early boot is not allowed to touch */
  40 static inline int bad_addr(unsigned long *addrp, unsigned long size)
  41 {
  42         unsigned long addr = *addrp, last = addr + size;
  43
  44         /* various gunk below that needed for SMP startup */
  45         if (addr < 0x8000) {
  46                 *addrp = 0x8000;
  47                 return 1;
  48         }
  49
  50         /* direct mapping tables of the kernel */
  51         if (last >= table_start<<PAGE_SHIFT && addr < table_end<<PAGE_SHIFT) {
  52                 *addrp = table_end << PAGE_SHIFT;
  53                 return 1;
  54         }
  55
  56         /* initrd */
  57 #ifdef CONFIG_BLK_DEV_INITRD
  58         if (LOADER_TYPE && INITRD_START && last >= INITRD_START &&
  59             addr < INITRD_START+INITRD_SIZE) {
  60                 *addrp = INITRD_START + INITRD_SIZE;
  61                 return 1;
  62         }
  63 #endif
  64         /* kernel code + 640k memory hole (later should not be needed, but
  65            be paranoid for now) */
  66         if (last >= 640*1024 && addr < __pa_symbol(&_end)) {
  67                 *addrp = __pa_symbol(&_end);
  68                 return 1;
  69         }
  70         /* XXX ramdisk image here? */
  71         return 0;
  72 }
  73
  74 int __init e820_mapped(unsigned long start, unsigned long end, unsigned type)
  75 {
  76         int i;
  77         for (i = 0; i < e820.nr_map; i++) {
  78                 struct e820entry *ei = &e820.map[i];
  79                 if (type && ei->type != type)
  80                         continue;
  81                 if (ei->addr >= end || ei->addr + ei->size < start)
  82                         continue;
  83                 return 1;
  84         }
  85         return 0;
  86 }
  87
  88 /*
  89  * Find a free area in a specific range.
  90  */
  91 unsigned long __init find_e820_area(unsigned long start, unsigned long end, unsigned size)
  92 {
  93         int i;
  94         for (i = 0; i < e820.nr_map; i++) {
  95                 struct e820entry *ei = &e820.map[i];
  96                 unsigned long addr = ei->addr, last;
  97                 if (ei->type != E820_RAM)
  98                         continue;
  99                 if (addr < start)
 100                         addr = start;
 101                 if (addr > ei->addr + ei->size)
 102                         continue;
 103                 while (bad_addr(&addr, size) && addr+size < ei->addr + ei->size)
 104                         ;
 105                 last = addr + size;
 106                 if (last > ei->addr + ei->size)
 107                         continue;
 108                 if (last > end)
 109                         continue;
 110                 return addr;
 111         }
 112         return -1UL;
 113 }
 114
 115 /*
 116  * Free bootmem based on the e820 table for a node.
 117  */
 118 void __init e820_bootmem_free(pg_data_t *pgdat, unsigned long start,unsigned long end)
 119 {
 120         int i;
 121         for (i = 0; i < e820.nr_map; i++) {
 122                 struct e820entry *ei = &e820.map[i];
 123                 unsigned long last, addr;
 124
 125                 if (ei->type != E820_RAM ||
 126                     ei->addr+ei->size <= start ||
 127                     ei->addr > end)
 128                         continue;
 129
 130                 addr = round_up(ei->addr, PAGE_SIZE);
 131                 if (addr < start)
 132                         addr = start;
 133
 134                 last = round_down(ei->addr + ei->size, PAGE_SIZE);
 135                 if (last >= end)
 136                         last = end;
 137
 138                 if (last > addr && last-addr >= PAGE_SIZE)
 139                         free_bootmem_node(pgdat, addr, last-addr);
 140         }
 141 }
 142
 143 /*
 144  * Find the highest page frame number we have available
 145  */
 146 unsigned long __init e820_end_of_ram(void)
 147 {
 148         int i;
 149         unsigned long end_pfn = 0;
 150
 151         for (i = 0; i < e820.nr_map; i++) {
 152                 struct e820entry *ei = &e820.map[i];
 153                 unsigned long start, end;
 154
 155                 start = round_up(ei->addr, PAGE_SIZE);
 156                 end = round_down(ei->addr + ei->size, PAGE_SIZE);
 157                 if (start >= end)
 158                         continue;
 159                 if (ei->type == E820_RAM) {
 160                 if (end > end_pfn<<PAGE_SHIFT)
 161                         end_pfn = end>>PAGE_SHIFT;
 162                 } else {
 163                         if (end > end_pfn_map<<PAGE_SHIFT)
 164                                 end_pfn_map = end>>PAGE_SHIFT;
 165                 }
 166         }
 167
 168         if (end_pfn > end_pfn_map)
 169                 end_pfn_map = end_pfn;
 170         if (end_pfn_map > MAXMEM>>PAGE_SHIFT)
 171                 end_pfn_map = MAXMEM>>PAGE_SHIFT;
 172         if (end_pfn > end_user_pfn)
 173                 end_pfn = end_user_pfn;
 174         if (end_pfn > end_pfn_map)
 175                 end_pfn = end_pfn_map;
 176
 177         return end_pfn;
 178 }
 179
 180 /*
 181  * Mark e820 reserved areas as busy for the resource manager.
 182  */
 183 void __init e820_reserve_resources(void)
 184 {
 185         int i;
 186         for (i = 0; i < e820.nr_map; i++) {
 187                 struct resource *res;
 188                 if (e820.map[i].addr + e820.map[i].size > 0x100000000ULL)
 189                         continue;
 190                 res = alloc_bootmem_low(sizeof(struct resource));
 191                 switch (e820.map[i].type) {
 192                 case E820_RAM:  res->name = "System RAM"; break;
 193                 case E820_ACPI: res->name = "ACPI Tables"; break;
 194                 case E820_NVS:  res->name = "ACPI Non-volatile Storage"; break;
 195                 default:        res->name = "reserved";
 196                 }
 197                 res->start = e820.map[i].addr;
 198                 res->end = res->start + e820.map[i].size - 1;
 199                 res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
 200                 request_resource(&iomem_resource, res);
 201                 if (e820.map[i].type == E820_RAM) {
 202                         /*
 203                          *  We don't know which RAM region contains kernel data,
 204                          *  so we try it repeatedly and let the resource manager
 205                          *  test it.
 206                          */
 207                         request_resource(res, &code_resource);
 208                         request_resource(res, &data_resource);
 209                 }
 210         }
 211 }
 212
 213 /*
 214  * Add a memory region to the kernel e820 map.
 215  */
 216 void __init add_memory_region(unsigned long start, unsigned long size, int type)
 217 {
 218         int x = e820.nr_map;
 219
 220         if (x == E820MAX) {
 221                 printk(KERN_ERR "Ooops! Too many entries in the memory map!\n");
 222                 return;
 223         }
 224
 225         e820.map[x].addr = start;
 226         e820.map[x].size = size;
 227         e820.map[x].type = type;
 228         e820.nr_map++;
 229 }
 230
 231 void __init e820_print_map(char *who)
 232 {
 233         int i;
 234
 235         for (i = 0; i < e820.nr_map; i++) {
 236                 printk(" %s: %016Lx - %016Lx ", who,
 237                         (unsigned long long) e820.map[i].addr,
 238                         (unsigned long long) (e820.map[i].addr + e820.map[i].size));
 239                 switch (e820.map[i].type) {
 240                 case E820_RAM:  printk("(usable)\n");
 241                                 break;
 242                 case E820_RESERVED:
 243                                 printk("(reserved)\n");
 244                                 break;
 245                 case E820_ACPI:
 246                                 printk("(ACPI data)\n");
 247                                 break;
 248                 case E820_NVS:
 249                                 printk("(ACPI NVS)\n");
 250                                 break;
 251                 default:        printk("type %u\n", e820.map[i].type);
 252                                 break;
 253                 }
 254         }
 255 }
 256
 257 /*
 258  * Sanitize the BIOS e820 map.
 259  *
 260  * Some e820 responses include overlapping entries.  The following
 261  * replaces the original e820 map with a new one, removing overlaps.
 262  *
 263  */
 264 static int __init sanitize_e820_map(struct e820entry * biosmap, char * pnr_map)
 265 {
 266         struct change_member {
 267                 struct e820entry *pbios; /* pointer to original bios entry */
 268                 unsigned long long addr; /* address for this change point */
 269         };
 270         static struct change_member change_point_list[2*E820MAX] __initdata;
 271         static struct change_member *change_point[2*E820MAX] __initdata;
 272         static struct e820entry *overlap_list[E820MAX] __initdata;
 273         static struct e820entry new_bios[E820MAX] __initdata;
 274         struct change_member *change_tmp;
 275         unsigned long current_type, last_type;
 276         unsigned long long last_addr;
 277         int chgidx, still_changing;
 278         int overlap_entries;
 279         int new_bios_entry;
 280         int old_nr, new_nr;
 281         int i;
 282
 283         /*
 284                 Visually we're performing the following (1,2,3,4 = memory types)...
 285
 286                 Sample memory map (w/overlaps):
 287                    ____22__________________
 288                    ______________________4_
 289                    ____1111________________
 290                    _44_____________________
 291                    11111111________________
 292                    ____________________33__
 293                    ___________44___________
 294                    __________33333_________
 295                    ______________22________
 296                    ___________________2222_
 297                    _________111111111______
 298                    _____________________11_
 299                    _________________4______
 300
 301                 Sanitized equivalent (no overlap):
 302                    1_______________________
 303                    _44_____________________
 304                    ___1____________________
 305                    ____22__________________
 306                    ______11________________
 307                    _________1______________
 308                    __________3_____________
 309                    ___________44___________
 310                    _____________33_________
 311                    _______________2________
 312                    ________________1_______
 313                    _________________4______
 314                    ___________________2____
 315                    ____________________33__
 316                    ______________________4_
 317         */
 318
 319         /* if there's only one memory region, don't bother */
 320         if (*pnr_map < 2)
 321                 return -1;
 322
 323         old_nr = *pnr_map;
 324
 325         /* bail out if we find any unreasonable addresses in bios map */
 326         for (i=0; i<old_nr; i++)
 327                 if (biosmap[i].addr + biosmap[i].size < biosmap[i].addr)
 328                         return -1;
 329
 330         /* create pointers for initial change-point information (for sorting) */
 331         for (i=0; i < 2*old_nr; i++)
 332                 change_point[i] = &change_point_list[i];
 333
 334         /* record all known change-points (starting and ending addresses) */
 335         chgidx = 0;
 336         for (i=0; i < old_nr; i++)      {
 337                 change_point[chgidx]->addr = biosmap[i].addr;
 338                 change_point[chgidx++]->pbios = &biosmap[i];
 339                 change_point[chgidx]->addr = biosmap[i].addr + biosmap[i].size;
 340                 change_point[chgidx++]->pbios = &biosmap[i];
 341         }
 342
 343         /* sort change-point list by memory addresses (low -> high) */
 344         still_changing = 1;
 345         while (still_changing)  {
 346                 still_changing = 0;
 347                 for (i=1; i < 2*old_nr; i++)  {
 348                         /* if <current_addr> > <last_addr>, swap */
 349                         /* or, if current=<start_addr> & last=<end_addr>, swap */
 350                         if ((change_point[i]->addr < change_point[i-1]->addr) ||
 351                                 ((change_point[i]->addr == change_point[i-1]->addr) &&
 352                                  (change_point[i]->addr == change_point[i]->pbios->addr) &&
 353                                  (change_point[i-1]->addr != change_point[i-1]->pbios->addr))
 354                            )
 355                         {
 356                                 change_tmp = change_point[i];
 357                                 change_point[i] = change_point[i-1];
 358                                 change_point[i-1] = change_tmp;
 359                                 still_changing=1;
 360                         }
 361                 }
 362         }
 363
 364         /* create a new bios memory map, removing overlaps */
 365         overlap_entries=0;       /* number of entries in the overlap table */
 366         new_bios_entry=0;        /* index for creating new bios map entries */
 367         last_type = 0;           /* start with undefined memory type */
 368         last_addr = 0;           /* start with 0 as last starting address */
 369         /* loop through change-points, determining affect on the new bios map */
 370         for (chgidx=0; chgidx < 2*old_nr; chgidx++)
 371         {
 372                 /* keep track of all overlapping bios entries */
 373                 if (change_point[chgidx]->addr == change_point[chgidx]->pbios->addr)
 374                 {
 375                         /* add map entry to overlap list (> 1 entry implies an overlap) */
 376                         overlap_list[overlap_entries++]=change_point[chgidx]->pbios;
 377                 }
 378                 else
 379                 {
 380                         /* remove entry from list (order independent, so swap with last) */
 381                         for (i=0; i<overlap_entries; i++)
 382                         {
 383                                 if (overlap_list[i] == change_point[chgidx]->pbios)
 384                                         overlap_list[i] = overlap_list[overlap_entries-1];
 385                         }
 386                         overlap_entries--;
 387                 }
 388                 /* if there are overlapping entries, decide which "type" to use */
 389                 /* (larger value takes precedence -- 1=usable, 2,3,4,4+=unusable) */
 390                 current_type = 0;
 391                 for (i=0; i<overlap_entries; i++)
 392                         if (overlap_list[i]->type > current_type)
 393                                 current_type = overlap_list[i]->type;
 394                 /* continue building up new bios map based on this information */
 395                 if (current_type != last_type)  {
 396                         if (last_type != 0)      {
 397                                 new_bios[new_bios_entry].size =
 398                                         change_point[chgidx]->addr - last_addr;
 399                                 /* move forward only if the new size was non-zero */
 400                                 if (new_bios[new_bios_entry].size != 0)
 401                                         if (++new_bios_entry >= E820MAX)
 402                                                 break;  /* no more space left for new bios entries */
 403                         }
 404                         if (current_type != 0)  {
 405                                 new_bios[new_bios_entry].addr = change_point[chgidx]->addr;
 406                                 new_bios[new_bios_entry].type = current_type;
 407                                 last_addr=change_point[chgidx]->addr;
 408                         }
 409                         last_type = current_type;
 410                 }
 411         }
 412         new_nr = new_bios_entry;   /* retain count for new bios entries */
 413
 414         /* copy new bios mapping into original location */
 415         memcpy(biosmap, new_bios, new_nr*sizeof(struct e820entry));
 416         *pnr_map = new_nr;
 417
 418         return 0;
 419 }
 420
 421 /*
 422  * Copy the BIOS e820 map into a safe place.
 423  *
 424  * Sanity-check it while we're at it..
 425  *
 426  * If we're lucky and live on a modern system, the setup code
 427  * will have given us a memory map that we can use to properly
 428  * set up memory.  If we aren't, we'll fake a memory map.
 429  *
 430  * We check to see that the memory map contains at least 2 elements
 431  * before we'll use it, because the detection code in setup.S may
 432  * not be perfect and most every PC known to man has two memory
 433  * regions: one from 0 to 640k, and one from 1mb up.  (The IBM
 434  * thinkpad 560x, for example, does not cooperate with the memory
 435  * detection code.)
 436  */
 437 static int __init copy_e820_map(struct e820entry * biosmap, int nr_map)
 438 {
 439         /* Only one memory region (or negative)? Ignore it */
 440         if (nr_map < 2)
 441                 return -1;
 442
 443         do {
 444                 unsigned long start = biosmap->addr;
 445                 unsigned long size = biosmap->size;
 446                 unsigned long end = start + size;
 447                 unsigned long type = biosmap->type;
 448
 449                 /* Overflow in 64 bits? Ignore the memory map. */
 450                 if (start > end)
 451                         return -1;
 452
 453                 /*
 454                  * Some BIOSes claim RAM in the 640k - 1M region.
 455                  * Not right. Fix it up.
 456                  *
 457                  * This should be removed on Hammer which is supposed to not
 458                  * have non e820 covered ISA mappings there, but I had some strange
 459                  * problems so it stays for now.  -AK
 460                  */
 461                 if (type == E820_RAM) {
 462                         if (start < 0x100000ULL && end > 0xA0000ULL) {
 463                                 if (start < 0xA0000ULL)
 464                                         add_memory_region(start, 0xA0000ULL-start, type);
 465                                 if (end <= 0x100000ULL)
 466                                         continue;
 467                                 start = 0x100000ULL;
 468                                 size = end - start;
 469                         }
 470                 }
 471
 472                 add_memory_region(start, size, type);
 473         } while (biosmap++,--nr_map);
 474         return 0;
 475 }
 476
 477 void __init setup_memory_region(void)
 478 {
 479         char *who = "BIOS-e820";
 480
 481         /*
 482          * Try to copy the BIOS-supplied E820-map.
 483          *
 484          * Otherwise fake a memory map; one section from 0k->640k,
 485          * the next section from 1mb->appropriate_mem_k
 486          */
 487         sanitize_e820_map(E820_MAP, &E820_MAP_NR);
 488         if (copy_e820_map(E820_MAP, E820_MAP_NR) < 0) {
 489                 unsigned long mem_size;
 490
 491                 /* compare results from other methods and take the greater */
 492                 if (ALT_MEM_K < EXT_MEM_K) {
 493                         mem_size = EXT_MEM_K;
 494                         who = "BIOS-88";
 495                 } else {
 496                         mem_size = ALT_MEM_K;
 497                         who = "BIOS-e801";
 498                 }
 499
 500                 e820.nr_map = 0;
 501                 add_memory_region(0, LOWMEMSIZE(), E820_RAM);
 502                 add_memory_region(HIGH_MEMORY, mem_size << 10, E820_RAM);
 503         }
 504         printk(KERN_INFO "BIOS-provided physical RAM map:\n");
 505         e820_print_map(who);
 506 }
 507
 508 void __init parse_memopt(char *p, char **from)
 509 {
 510         end_user_pfn = memparse(p, from);
 511         end_user_pfn >>= PAGE_SHIFT;
 512 }
 513
 514 unsigned long pci_mem_start = 0xaeedbabe;
 515
 516 /*
 517  * Search for the biggest gap in the low 32 bits of the e820
 518  * memory space.  We pass this space to PCI to assign MMIO resources
 519  * for hotplug or unconfigured devices in.
 520  * Hopefully the BIOS let enough space left.
 521  */
 522 __init void e820_setup_gap(void)
 523 {
 524         unsigned long gapstart, gapsize;
 525         unsigned long last;
 526         int i;
 527         int found = 0;
 528
 529         last = 0x100000000ull;
 530         gapstart = 0x10000000;
 531         gapsize = 0x400000;
 532         i = e820.nr_map;
 533         while (--i >= 0) {
 534                 unsigned long long start = e820.map[i].addr;
 535                 unsigned long long end = start + e820.map[i].size;
 536
 537                 /*
 538                  * Since "last" is at most 4GB, we know we'll
 539                  * fit in 32 bits if this condition is true
 540                  */
 541                 if (last > end) {
 542                         unsigned long gap = last - end;
 543
 544                         if (gap > gapsize) {
 545                                 gapsize = gap;
 546                                 gapstart = end;
 547                                 found = 1;
 548                         }
 549                 }
 550                 if (start < last)
 551                         last = start;
 552         }
 553
 554         if (!found) {
 555                 gapstart = (end_pfn << PAGE_SHIFT) + 1024*1024;
 556                 printk(KERN_ERR "PCI: Warning: Cannot find a gap in the 32bit address range\n"
 557                        KERN_ERR "PCI: Unassigned devices with 32bit resource registers may break!\n");
 558         }
 559
 560         /*
 561          * Start allocating dynamic PCI memory a bit into the gap,
 562          * aligned up to the nearest megabyte.
 563          *
 564          * Question: should we try to pad it up a bit (do something
 565          * like " + (gapsize >> 3)" in there too?). We now have the
 566          * technology.
 567          */
 568         pci_mem_start = (gapstart + 0xfffff) & ~0xfffff;
 569
 570         printk(KERN_INFO "Allocating PCI resources starting at %lx (gap: %lx:%lx)\n",
 571                 pci_mem_start, gapstart, gapsize);
 572 }