arch/x86/kernel/e820.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/pfn.h>
  21
  22 #include <asm/pgtable.h>
  23 #include <asm/page.h>
  24 #include <asm/e820.h>
  25 #include <asm/setup.h>
  26
  27 struct e820map e820;
  28
  29 /* For PCI or other memory-mapped resources */
  30 unsigned long pci_mem_start = 0xaeedbabe;
  31 #ifdef CONFIG_PCI
  32 EXPORT_SYMBOL(pci_mem_start);
  33 #endif
  34
  35 /*
  36  * This function checks if any part of the range <start,end> is mapped
  37  * with type.
  38  */
  39 int
  40 e820_any_mapped(u64 start, u64 end, unsigned type)
  41 {
  42         int i;
  43
  44         for (i = 0; i < e820.nr_map; i++) {
  45                 struct e820entry *ei = &e820.map[i];
  46
  47                 if (type && ei->type != type)
  48                         continue;
  49                 if (ei->addr >= end || ei->addr + ei->size <= start)
  50                         continue;
  51                 return 1;
  52         }
  53         return 0;
  54 }
  55 EXPORT_SYMBOL_GPL(e820_any_mapped);
  56
  57 /*
  58  * This function checks if the entire range <start,end> is mapped with type.
  59  *
  60  * Note: this function only works correct if the e820 table is sorted and
  61  * not-overlapping, which is the case
  62  */
  63 int __init e820_all_mapped(u64 start, u64 end, unsigned type)
  64 {
  65         int i;
  66
  67         for (i = 0; i < e820.nr_map; i++) {
  68                 struct e820entry *ei = &e820.map[i];
  69
  70                 if (type && ei->type != type)
  71                         continue;
  72                 /* is the region (part) in overlap with the current region ?*/
  73                 if (ei->addr >= end || ei->addr + ei->size <= start)
  74                         continue;
  75
  76                 /* if the region is at the beginning of <start,end> we move
  77                  * start to the end of the region since it's ok until there
  78                  */
  79                 if (ei->addr <= start)
  80                         start = ei->addr + ei->size;
  81                 /*
  82                  * if start is now at or beyond end, we're done, full
  83                  * coverage
  84                  */
  85                 if (start >= end)
  86                         return 1;
  87         }
  88         return 0;
  89 }
  90
  91 /*
  92  * Add a memory region to the kernel e820 map.
  93  */
  94 void __init add_memory_region(u64 start, u64 size, int type)
  95 {
  96         int x = e820.nr_map;
  97
  98         if (x == E820MAX) {
  99                 printk(KERN_ERR "Ooops! Too many entries in the memory map!\n");
 100                 return;
 101         }
 102
 103         e820.map[x].addr = start;
 104         e820.map[x].size = size;
 105         e820.map[x].type = type;
 106         e820.nr_map++;
 107 }
 108
 109 void __init e820_print_map(char *who)
 110 {
 111         int i;
 112
 113         for (i = 0; i < e820.nr_map; i++) {
 114                 printk(KERN_INFO " %s: %016Lx - %016Lx ", who,
 115                        (unsigned long long) e820.map[i].addr,
 116                        (unsigned long long)
 117                        (e820.map[i].addr + e820.map[i].size));
 118                 switch (e820.map[i].type) {
 119                 case E820_RAM:
 120                         printk(KERN_CONT "(usable)\n");
 121                         break;
 122                 case E820_RESERVED:
 123                         printk(KERN_CONT "(reserved)\n");
 124                         break;
 125                 case E820_ACPI:
 126                         printk(KERN_CONT "(ACPI data)\n");
 127                         break;
 128                 case E820_NVS:
 129                         printk(KERN_CONT "(ACPI NVS)\n");
 130                         break;
 131                 default:
 132                         printk(KERN_CONT "type %u\n", e820.map[i].type);
 133                         break;
 134                 }
 135         }
 136 }
 137
 138 /*
 139  * Sanitize the BIOS e820 map.
 140  *
 141  * Some e820 responses include overlapping entries. The following
 142  * replaces the original e820 map with a new one, removing overlaps.
 143  *
 144  */
 145 int __init sanitize_e820_map(struct e820entry *biosmap, char *pnr_map)
 146 {
 147         struct change_member {
 148                 struct e820entry *pbios; /* pointer to original bios entry */
 149                 unsigned long long addr; /* address for this change point */
 150         };
 151         static struct change_member change_point_list[2*E820MAX] __initdata;
 152         static struct change_member *change_point[2*E820MAX] __initdata;
 153         static struct e820entry *overlap_list[E820MAX] __initdata;
 154         static struct e820entry new_bios[E820MAX] __initdata;
 155         struct change_member *change_tmp;
 156         unsigned long current_type, last_type;
 157         unsigned long long last_addr;
 158         int chgidx, still_changing;
 159         int overlap_entries;
 160         int new_bios_entry;
 161         int old_nr, new_nr, chg_nr;
 162         int i;
 163
 164         /*
 165                 Visually we're performing the following
 166                 (1,2,3,4 = memory types)...
 167
 168                 Sample memory map (w/overlaps):
 169                    ____22__________________
 170                    ______________________4_
 171                    ____1111________________
 172                    _44_____________________
 173                    11111111________________
 174                    ____________________33__
 175                    ___________44___________
 176                    __________33333_________
 177                    ______________22________
 178                    ___________________2222_
 179                    _________111111111______
 180                    _____________________11_
 181                    _________________4______
 182
 183                 Sanitized equivalent (no overlap):
 184                    1_______________________
 185                    _44_____________________
 186                    ___1____________________
 187                    ____22__________________
 188                    ______11________________
 189                    _________1______________
 190                    __________3_____________
 191                    ___________44___________
 192                    _____________33_________
 193                    _______________2________
 194                    ________________1_______
 195                    _________________4______
 196                    ___________________2____
 197                    ____________________33__
 198                    ______________________4_
 199         */
 200
 201         /* if there's only one memory region, don't bother */
 202         if (*pnr_map < 2)
 203                 return -1;
 204
 205         old_nr = *pnr_map;
 206
 207         /* bail out if we find any unreasonable addresses in bios map */
 208         for (i = 0; i < old_nr; i++)
 209                 if (biosmap[i].addr + biosmap[i].size < biosmap[i].addr)
 210                         return -1;
 211
 212         /* create pointers for initial change-point information (for sorting) */
 213         for (i = 0; i < 2 * old_nr; i++)
 214                 change_point[i] = &change_point_list[i];
 215
 216         /* record all known change-points (starting and ending addresses),
 217            omitting those that are for empty memory regions */
 218         chgidx = 0;
 219         for (i = 0; i < old_nr; i++)    {
 220                 if (biosmap[i].size != 0) {
 221                         change_point[chgidx]->addr = biosmap[i].addr;
 222                         change_point[chgidx++]->pbios = &biosmap[i];
 223                         change_point[chgidx]->addr = biosmap[i].addr +
 224                                 biosmap[i].size;
 225                         change_point[chgidx++]->pbios = &biosmap[i];
 226                 }
 227         }
 228         chg_nr = chgidx;
 229
 230         /* sort change-point list by memory addresses (low -> high) */
 231         still_changing = 1;
 232         while (still_changing)  {
 233                 still_changing = 0;
 234                 for (i = 1; i < chg_nr; i++)  {
 235                         unsigned long long curaddr, lastaddr;
 236                         unsigned long long curpbaddr, lastpbaddr;
 237
 238                         curaddr = change_point[i]->addr;
 239                         lastaddr = change_point[i - 1]->addr;
 240                         curpbaddr = change_point[i]->pbios->addr;
 241                         lastpbaddr = change_point[i - 1]->pbios->addr;
 242
 243                         /*
 244                          * swap entries, when:
 245                          *
 246                          * curaddr > lastaddr or
 247                          * curaddr == lastaddr and curaddr == curpbaddr and
 248                          * lastaddr != lastpbaddr
 249                          */
 250                         if (curaddr < lastaddr ||
 251                             (curaddr == lastaddr && curaddr == curpbaddr &&
 252                              lastaddr != lastpbaddr)) {
 253                                 change_tmp = change_point[i];
 254                                 change_point[i] = change_point[i-1];
 255                                 change_point[i-1] = change_tmp;
 256                                 still_changing = 1;
 257                         }
 258                 }
 259         }
 260
 261         /* create a new bios memory map, removing overlaps */
 262         overlap_entries = 0;     /* number of entries in the overlap table */
 263         new_bios_entry = 0;      /* index for creating new bios map entries */
 264         last_type = 0;           /* start with undefined memory type */
 265         last_addr = 0;           /* start with 0 as last starting address */
 266
 267         /* loop through change-points, determining affect on the new bios map */
 268         for (chgidx = 0; chgidx < chg_nr; chgidx++) {
 269                 /* keep track of all overlapping bios entries */
 270                 if (change_point[chgidx]->addr ==
 271                     change_point[chgidx]->pbios->addr) {
 272                         /*
 273                          * add map entry to overlap list (> 1 entry
 274                          * implies an overlap)
 275                          */
 276                         overlap_list[overlap_entries++] =
 277                                 change_point[chgidx]->pbios;
 278                 } else {
 279                         /*
 280                          * remove entry from list (order independent,
 281                          * so swap with last)
 282                          */
 283                         for (i = 0; i < overlap_entries; i++) {
 284                                 if (overlap_list[i] ==
 285                                     change_point[chgidx]->pbios)
 286                                         overlap_list[i] =
 287                                                 overlap_list[overlap_entries-1];
 288                         }
 289                         overlap_entries--;
 290                 }
 291                 /*
 292                  * if there are overlapping entries, decide which
 293                  * "type" to use (larger value takes precedence --
 294                  * 1=usable, 2,3,4,4+=unusable)
 295                  */
 296                 current_type = 0;
 297                 for (i = 0; i < overlap_entries; i++)
 298                         if (overlap_list[i]->type > current_type)
 299                                 current_type = overlap_list[i]->type;
 300                 /*
 301                  * continue building up new bios map based on this
 302                  * information
 303                  */
 304                 if (current_type != last_type)  {
 305                         if (last_type != 0)      {
 306                                 new_bios[new_bios_entry].size =
 307                                         change_point[chgidx]->addr - last_addr;
 308                                 /*
 309                                  * move forward only if the new size
 310                                  * was non-zero
 311                                  */
 312                                 if (new_bios[new_bios_entry].size != 0)
 313                                         /*
 314                                          * no more space left for new
 315                                          * bios entries ?
 316                                          */
 317                                         if (++new_bios_entry >= E820MAX)
 318                                                 break;
 319                         }
 320                         if (current_type != 0)  {
 321                                 new_bios[new_bios_entry].addr =
 322                                         change_point[chgidx]->addr;
 323                                 new_bios[new_bios_entry].type = current_type;
 324                                 last_addr = change_point[chgidx]->addr;
 325                         }
 326                         last_type = current_type;
 327                 }
 328         }
 329         /* retain count for new bios entries */
 330         new_nr = new_bios_entry;
 331
 332         /* copy new bios mapping into original location */
 333         memcpy(biosmap, new_bios, new_nr * sizeof(struct e820entry));
 334         *pnr_map = new_nr;
 335
 336         return 0;
 337 }
 338
 339 /*
 340  * Copy the BIOS e820 map into a safe place.
 341  *
 342  * Sanity-check it while we're at it..
 343  *
 344  * If we're lucky and live on a modern system, the setup code
 345  * will have given us a memory map that we can use to properly
 346  * set up memory.  If we aren't, we'll fake a memory map.
 347  */
 348 int __init copy_e820_map(struct e820entry *biosmap, int nr_map)
 349 {
 350         /* Only one memory region (or negative)? Ignore it */
 351         if (nr_map < 2)
 352                 return -1;
 353
 354         do {
 355                 u64 start = biosmap->addr;
 356                 u64 size = biosmap->size;
 357                 u64 end = start + size;
 358                 u32 type = biosmap->type;
 359
 360                 /* Overflow in 64 bits? Ignore the memory map. */
 361                 if (start > end)
 362                         return -1;
 363
 364                 add_memory_region(start, size, type);
 365         } while (biosmap++, --nr_map);
 366         return 0;
 367 }
 368
 369 u64 __init update_memory_range(u64 start, u64 size, unsigned old_type,
 370                                 unsigned new_type)
 371 {
 372         int i;
 373         u64 real_updated_size = 0;
 374
 375         BUG_ON(old_type == new_type);
 376
 377         for (i = 0; i < e820.nr_map; i++) {
 378                 struct e820entry *ei = &e820.map[i];
 379                 u64 final_start, final_end;
 380                 if (ei->type != old_type)
 381                         continue;
 382                 /* totally covered? */
 383                 if (ei->addr >= start &&
 384                     (ei->addr + ei->size) <= (start + size)) {
 385                         ei->type = new_type;
 386                         real_updated_size += ei->size;
 387                         continue;
 388                 }
 389                 /* partially covered */
 390                 final_start = max(start, ei->addr);
 391                 final_end = min(start + size, ei->addr + ei->size);
 392                 if (final_start >= final_end)
 393                         continue;
 394                 add_memory_region(final_start, final_end - final_start,
 395                                          new_type);
 396                 real_updated_size += final_end - final_start;
 397         }
 398         return real_updated_size;
 399 }
 400
 401 void __init update_e820(void)
 402 {
 403         u8 nr_map;
 404
 405         nr_map = e820.nr_map;
 406         if (sanitize_e820_map(e820.map, &nr_map))
 407                 return;
 408         e820.nr_map = nr_map;
 409         printk(KERN_INFO "modified physical RAM map:\n");
 410         e820_print_map("modified");
 411 }
 412
 413 /*
 414  * Search for the biggest gap in the low 32 bits of the e820
 415  * memory space.  We pass this space to PCI to assign MMIO resources
 416  * for hotplug or unconfigured devices in.
 417  * Hopefully the BIOS let enough space left.
 418  */
 419 __init void e820_setup_gap(void)
 420 {
 421         unsigned long gapstart, gapsize, round;
 422         unsigned long long last;
 423         int i;
 424         int found = 0;
 425
 426         last = 0x100000000ull;
 427         gapstart = 0x10000000;
 428         gapsize = 0x400000;
 429         i = e820.nr_map;
 430         while (--i >= 0) {
 431                 unsigned long long start = e820.map[i].addr;
 432                 unsigned long long end = start + e820.map[i].size;
 433
 434                 /*
 435                  * Since "last" is at most 4GB, we know we'll
 436                  * fit in 32 bits if this condition is true
 437                  */
 438                 if (last > end) {
 439                         unsigned long gap = last - end;
 440
 441                         if (gap > gapsize) {
 442                                 gapsize = gap;
 443                                 gapstart = end;
 444                                 found = 1;
 445                         }
 446                 }
 447                 if (start < last)
 448                         last = start;
 449         }
 450
 451 #ifdef CONFIG_X86_64
 452         if (!found) {
 453                 gapstart = (end_pfn << PAGE_SHIFT) + 1024*1024;
 454                 printk(KERN_ERR "PCI: Warning: Cannot find a gap in the 32bit "
 455                        "address range\n"
 456                        KERN_ERR "PCI: Unassigned devices with 32bit resource "
 457                        "registers may break!\n");
 458         }
 459 #endif
 460
 461         /*
 462          * See how much we want to round up: start off with
 463          * rounding to the next 1MB area.
 464          */
 465         round = 0x100000;
 466         while ((gapsize >> 4) > round)
 467                 round += round;
 468         /* Fun with two's complement */
 469         pci_mem_start = (gapstart + round) & -round;
 470
 471         printk(KERN_INFO
 472                "Allocating PCI resources starting at %lx (gap: %lx:%lx)\n",
 473                pci_mem_start, gapstart, gapsize);
 474 }
 475