arch/xen/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 /*
  19  * PFN of last memory page.
  20  */
  21 unsigned long end_pfn;
  22 unsigned long end_user_pfn = MAXMEM>>PAGE_SHIFT;
  23 unsigned long end_pfn_map;
  24
  25 /*
  26  * Add a memory region to the kernel e820 map.
  27  */
  28 void __init add_memory_region(unsigned long start, unsigned long size, int type)
  29 {
  30         int x = e820.nr_map;
  31
  32         if (x == E820MAX) {
  33                 printk(KERN_ERR "Ooops! Too many entries in the memory map!\n");
  34                 return;
  35         }
  36
  37         e820.map[x].addr = start;
  38         e820.map[x].size = size;
  39         e820.map[x].type = type;
  40         e820.nr_map++;
  41 }
  42
  43 #if 0
  44 extern char _end[];
  45
  46 /*
  47  * end_pfn only includes RAM, while end_pfn_map includes all e820 entries.
  48  * The direct mapping extends to end_pfn_map, so that we can directly access
  49  * apertures, ACPI and other tables without having to play with fixmaps.
  50  */
  51
  52 /*
  53  * Last pfn which the user wants to use.
  54  */
  55
  56 extern struct resource code_resource, data_resource;
  57
  58 /* Check for some hardcoded bad areas that early boot is not allowed to touch */
  59 static inline int bad_addr(unsigned long *addrp, unsigned long size)
  60 {
  61         unsigned long addr = *addrp, last = addr + size;
  62
  63         /* various gunk below that needed for SMP startup */
  64         if (addr < 0x8000) {
  65                 *addrp = 0x8000;
  66                 return 1;
  67         }
  68
  69         /* direct mapping tables of the kernel */
  70         if (last >= table_start<<PAGE_SHIFT && addr < table_end<<PAGE_SHIFT) {
  71                 *addrp = table_end << PAGE_SHIFT;
  72                 return 1;
  73         }
  74
  75         /* initrd */
  76 #ifdef CONFIG_BLK_DEV_INITRD
  77         if (LOADER_TYPE && INITRD_START && last >= INITRD_START &&
  78             addr < INITRD_START+INITRD_SIZE) {
  79                 *addrp = INITRD_START + INITRD_SIZE;
  80                 return 1;
  81         }
  82 #endif
  83         /* kernel code + 640k memory hole (later should not be needed, but
  84            be paranoid for now) */
  85         if (last >= 640*1024 && addr < __pa_symbol(&_end)) {
  86                 *addrp = __pa_symbol(&_end);
  87                 return 1;
  88         }
  89         /* XXX ramdisk image here? */
  90         return 0;
  91 }
  92
  93 int __init e820_mapped(unsigned long start, unsigned long end, unsigned type)
  94 {
  95         int i;
  96         for (i = 0; i < e820.nr_map; i++) {
  97                 struct e820entry *ei = &e820.map[i];
  98                 if (type && ei->type != type)
  99                         continue;
 100                 if (ei->addr >= end || ei->addr + ei->size < start)
 101                         continue;
 102                 return 1;
 103         }
 104         return 0;
 105 }
 106
 107 /*
 108  * Find a free area in a specific range.
 109  */
 110 unsigned long __init find_e820_area(unsigned long start, unsigned long end, unsigned size)
 111 {
 112         int i;
 113         for (i = 0; i < e820.nr_map; i++) {
 114                 struct e820entry *ei = &e820.map[i];
 115                 unsigned long addr = ei->addr, last;
 116                 if (ei->type != E820_RAM)
 117                         continue;
 118                 if (addr < start)
 119                         addr = start;
 120                 if (addr > ei->addr + ei->size)
 121                         continue;
 122                 while (bad_addr(&addr, size) && addr+size < ei->addr + ei->size)
 123                         ;
 124                 last = addr + size;
 125                 if (last > ei->addr + ei->size)
 126                         continue;
 127                 if (last > end)
 128                         continue;
 129                 return addr;
 130         }
 131         return -1UL;
 132 }
 133
 134 /*
 135  * Free bootmem based on the e820 table for a node.
 136  */
 137 void __init e820_bootmem_free(pg_data_t *pgdat, unsigned long start,unsigned long end)
 138 {
 139         int i;
 140         for (i = 0; i < e820.nr_map; i++) {
 141                 struct e820entry *ei = &e820.map[i];
 142                 unsigned long last, addr;
 143
 144                 if (ei->type != E820_RAM ||
 145                     ei->addr+ei->size <= start ||
 146                     ei->addr > end)
 147                         continue;
 148
 149                 addr = round_up(ei->addr, PAGE_SIZE);
 150                 if (addr < start)
 151                         addr = start;
 152
 153                 last = round_down(ei->addr + ei->size, PAGE_SIZE);
 154                 if (last >= end)
 155                         last = end;
 156
 157                 if (last > addr && last-addr >= PAGE_SIZE)
 158                         free_bootmem_node(pgdat, addr, last-addr);
 159         }
 160 }
 161
 162 /*
 163  * Find the highest page frame number we have available
 164  */
 165 unsigned long __init e820_end_of_ram(void)
 166 {
 167         int i;
 168         unsigned long end_pfn = 0;
 169
 170         for (i = 0; i < e820.nr_map; i++) {
 171                 struct e820entry *ei = &e820.map[i];
 172                 unsigned long start, end;
 173
 174                 start = round_up(ei->addr, PAGE_SIZE);
 175                 end = round_down(ei->addr + ei->size, PAGE_SIZE);
 176                 if (start >= end)
 177                         continue;
 178                 if (ei->type == E820_RAM) {
 179                 if (end > end_pfn<<PAGE_SHIFT)
 180                         end_pfn = end>>PAGE_SHIFT;
 181                 } else {
 182                         if (end > end_pfn_map<<PAGE_SHIFT)
 183                                 end_pfn_map = end>>PAGE_SHIFT;
 184                 }
 185         }
 186
 187         if (end_pfn > end_pfn_map)
 188                 end_pfn_map = end_pfn;
 189         if (end_pfn_map > MAXMEM>>PAGE_SHIFT)
 190                 end_pfn_map = MAXMEM>>PAGE_SHIFT;
 191         if (end_pfn > end_user_pfn)
 192                 end_pfn = end_user_pfn;
 193         if (end_pfn > end_pfn_map)
 194                 end_pfn = end_pfn_map;
 195
 196         return end_pfn;
 197 }
 198
 199 /*
 200  * Mark e820 reserved areas as busy for the resource manager.
 201  */
 202 void __init e820_reserve_resources(void)
 203 {
 204         int i;
 205         for (i = 0; i < e820.nr_map; i++) {
 206                 struct resource *res;
 207                 if (e820.map[i].addr + e820.map[i].size > 0x100000000ULL)
 208                         continue;
 209                 res = alloc_bootmem_low(sizeof(struct resource));
 210                 switch (e820.map[i].type) {
 211                 case E820_RAM:  res->name = "System RAM"; break;
 212                 case E820_ACPI: res->name = "ACPI Tables"; break;
 213                 case E820_NVS:  res->name = "ACPI Non-volatile Storage"; break;
 214                 default:        res->name = "reserved";
 215                 }
 216                 res->start = e820.map[i].addr;
 217                 res->end = res->start + e820.map[i].size - 1;
 218                 res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
 219                 request_resource(&iomem_resource, res);
 220                 if (e820.map[i].type == E820_RAM) {
 221                         /*
 222                          *  We don't know which RAM region contains kernel data,
 223                          *  so we try it repeatedly and let the resource manager
 224                          *  test it.
 225                          */
 226                         request_resource(res, &code_resource);
 227                         request_resource(res, &data_resource);
 228                 }
 229         }
 230 }
 231
 232
 233 void __init e820_print_map(char *who)
 234 {
 235         int i;
 236
 237         for (i = 0; i < e820.nr_map; i++) {
 238                 printk(" %s: %016Lx - %016Lx ", who,
 239                         (unsigned long long) e820.map[i].addr,
 240                         (unsigned long long) (e820.map[i].addr + e820.map[i].size));
 241                 switch (e820.map[i].type) {
 242                 case E820_RAM:  printk("(usable)\n");
 243                                 break;
 244                 case E820_RESERVED:
 245                                 printk("(reserved)\n");
 246                                 break;
 247                 case E820_ACPI:
 248                                 printk("(ACPI data)\n");
 249                                 break;
 250                 case E820_NVS:
 251                                 printk("(ACPI NVS)\n");
 252                                 break;
 253                 default:        printk("type %u\n", e820.map[i].type);
 254                                 break;
 255                 }
 256         }
 257 }
 258
 259 /*
 260  * Sanitize the BIOS e820 map.
 261  *
 262  * Some e820 responses include overlapping entries.  The following
 263  * replaces the original e820 map with a new one, removing overlaps.
 264  *
 265  */
 266 static int __init sanitize_e820_map(struct e820entry * biosmap, char * pnr_map)
 267 {
 268         struct change_member {
 269                 struct e820entry *pbios; /* pointer to original bios entry */
 270                 unsigned long long addr; /* address for this change point */
 271         };
 272         static struct change_member change_point_list[2*E820MAX] __initdata;
 273         static struct change_member *change_point[2*E820MAX] __initdata;
 274         static struct e820entry *overlap_list[E820MAX] __initdata;
 275         static struct e820entry new_bios[E820MAX] __initdata;
 276         struct change_member *change_tmp;
 277         unsigned long current_type, last_type;
 278         unsigned long long last_addr;
 279         int chgidx, still_changing;
 280         int overlap_entries;
 281         int new_bios_entry;
 282         int old_nr, new_nr;
 283         int i;
 284
 285         /*
 286                 Visually we're performing the following (1,2,3,4 = memory types)...
 287
 288                 Sample memory map (w/overlaps):
 289                    ____22__________________
 290                    ______________________4_
 291                    ____1111________________
 292                    _44_____________________
 293                    11111111________________
 294                    ____________________33__
 295                    ___________44___________
 296                    __________33333_________
 297                    ______________22________
 298                    ___________________2222_
 299                    _________111111111______
 300                    _____________________11_
 301                    _________________4______
 302
 303                 Sanitized equivalent (no overlap):
 304                    1_______________________
 305                    _44_____________________
 306                    ___1____________________
 307                    ____22__________________
 308                    ______11________________
 309                    _________1______________
 310                    __________3_____________
 311                    ___________44___________
 312                    _____________33_________
 313                    _______________2________
 314                    ________________1_______
 315                    _________________4______
 316                    ___________________2____
 317                    ____________________33__
 318                    ______________________4_
 319         */
 320
 321         /* if there's only one memory region, don't bother */
 322         if (*pnr_map < 2)
 323                 return -1;
 324
 325         old_nr = *pnr_map;
 326
 327         /* bail out if we find any unreasonable addresses in bios map */
 328         for (i=0; i<old_nr; i++)
 329                 if (biosmap[i].addr + biosmap[i].size < biosmap[i].addr)
 330                         return -1;
 331
 332         /* create pointers for initial change-point information (for sorting) */
 333         for (i=0; i < 2*old_nr; i++)
 334                 change_point[i] = &change_point_list[i];
 335
 336         /* record all known change-points (starting and ending addresses) */
 337         chgidx = 0;
 338         for (i=0; i < old_nr; i++)      {
 339                 change_point[chgidx]->addr = biosmap[i].addr;
 340                 change_point[chgidx++]->pbios = &biosmap[i];
 341                 change_point[chgidx]->addr = biosmap[i].addr + biosmap[i].size;
 342                 change_point[chgidx++]->pbios = &biosmap[i];
 343         }
 344
 345         /* sort change-point list by memory addresses (low -> high) */
 346         still_changing = 1;
 347         while (still_changing)  {
 348                 still_changing = 0;
 349                 for (i=1; i < 2*old_nr; i++)  {
 350                         /* if <current_addr> > <last_addr>, swap */
 351                         /* or, if current=<start_addr> & last=<end_addr>, swap */
 352                         if ((change_point[i]->addr < change_point[i-1]->addr) ||
 353                                 ((change_point[i]->addr == change_point[i-1]->addr) &&
 354                                  (change_point[i]->addr == change_point[i]->pbios->addr) &&
 355                                  (change_point[i-1]->addr != change_point[i-1]->pbios->addr))
 356                            )
 357                         {
 358                                 change_tmp = change_point[i];
 359                                 change_point[i] = change_point[i-1];
 360                                 change_point[i-1] = change_tmp;
 361                                 still_changing=1;
 362                         }
 363                 }
 364         }
 365
 366         /* create a new bios memory map, removing overlaps */
 367         overlap_entries=0;       /* number of entries in the overlap table */
 368         new_bios_entry=0;        /* index for creating new bios map entries */
 369         last_type = 0;           /* start with undefined memory type */
 370         last_addr = 0;           /* start with 0 as last starting address */
 371         /* loop through change-points, determining affect on the new bios map */
 372         for (chgidx=0; chgidx < 2*old_nr; chgidx++)
 373         {
 374                 /* keep track of all overlapping bios entries */
 375                 if (change_point[chgidx]->addr == change_point[chgidx]->pbios->addr)
 376                 {
 377                         /* add map entry to overlap list (> 1 entry implies an overlap) */
 378                         overlap_list[overlap_entries++]=change_point[chgidx]->pbios;
 379                 }
 380                 else
 381                 {
 382                         /* remove entry from list (order independent, so swap with last) */
 383                         for (i=0; i<overlap_entries; i++)
 384                         {
 385                                 if (overlap_list[i] == change_point[chgidx]->pbios)
 386                                         overlap_list[i] = overlap_list[overlap_entries-1];
 387                         }
 388                         overlap_entries--;
 389                 }
 390                 /* if there are overlapping entries, decide which "type" to use */
 391                 /* (larger value takes precedence -- 1=usable, 2,3,4,4+=unusable) */
 392                 current_type = 0;
 393                 for (i=0; i<overlap_entries; i++)
 394                         if (overlap_list[i]->type > current_type)
 395                                 current_type = overlap_list[i]->type;
 396                 /* continue building up new bios map based on this information */
 397                 if (current_type != last_type)  {
 398                         if (last_type != 0)      {
 399                                 new_bios[new_bios_entry].size =
 400                                         change_point[chgidx]->addr - last_addr;
 401                                 /* move forward only if the new size was non-zero */
 402                                 if (new_bios[new_bios_entry].size != 0)
 403                                         if (++new_bios_entry >= E820MAX)
 404                                                 break;  /* no more space left for new bios entries */
 405                         }
 406                         if (current_type != 0)  {
 407                                 new_bios[new_bios_entry].addr = change_point[chgidx]->addr;
 408                                 new_bios[new_bios_entry].type = current_type;
 409                                 last_addr=change_point[chgidx]->addr;
 410                         }
 411                         last_type = current_type;
 412                 }
 413         }
 414         new_nr = new_bios_entry;   /* retain count for new bios entries */
 415
 416         /* copy new bios mapping into original location */
 417         memcpy(biosmap, new_bios, new_nr*sizeof(struct e820entry));
 418         *pnr_map = new_nr;
 419
 420         return 0;
 421 }
 422
 423 /*
 424  * Copy the BIOS e820 map into a safe place.
 425  *
 426  * Sanity-check it while we're at it..
 427  *
 428  * If we're lucky and live on a modern system, the setup code
 429  * will have given us a memory map that we can use to properly
 430  * set up memory.  If we aren't, we'll fake a memory map.
 431  *
 432  * We check to see that the memory map contains at least 2 elements
 433  * before we'll use it, because the detection code in setup.S may
 434  * not be perfect and most every PC known to man has two memory
 435  * regions: one from 0 to 640k, and one from 1mb up.  (The IBM
 436  * thinkpad 560x, for example, does not cooperate with the memory
 437  * detection code.)
 438  */
 439 static int __init copy_e820_map(struct e820entry * biosmap, int nr_map)
 440 {
 441         /* Only one memory region (or negative)? Ignore it */
 442         if (nr_map < 2)
 443                 return -1;
 444
 445         do {
 446                 unsigned long start = biosmap->addr;
 447                 unsigned long size = biosmap->size;
 448                 unsigned long end = start + size;
 449                 unsigned long type = biosmap->type;
 450
 451                 /* Overflow in 64 bits? Ignore the memory map. */
 452                 if (start > end)
 453                         return -1;
 454
 455                 /*
 456                  * Some BIOSes claim RAM in the 640k - 1M region.
 457                  * Not right. Fix it up.
 458                  *
 459                  * This should be removed on Hammer which is supposed to not
 460                  * have non e820 covered ISA mappings there, but I had some strange
 461                  * problems so it stays for now.  -AK
 462                  */
 463                 if (type == E820_RAM) {
 464                         if (start < 0x100000ULL && end > 0xA0000ULL) {
 465                                 if (start < 0xA0000ULL)
 466                                         add_memory_region(start, 0xA0000ULL-start, type);
 467                                 if (end <= 0x100000ULL)
 468                                         continue;
 469                                 start = 0x100000ULL;
 470                                 size = end - start;
 471                         }
 472                 }
 473
 474                 add_memory_region(start, size, type);
 475         } while (biosmap++,--nr_map);
 476         return 0;
 477 }
 478
 479 void __init setup_memory_region(void)
 480 {
 481         char *who = "BIOS-e820";
 482
 483         /*
 484          * Try to copy the BIOS-supplied E820-map.
 485          *
 486          * Otherwise fake a memory map; one section from 0k->640k,
 487          * the next section from 1mb->appropriate_mem_k
 488          */
 489         sanitize_e820_map(E820_MAP, &E820_MAP_NR);
 490         if (copy_e820_map(E820_MAP, E820_MAP_NR) < 0) {
 491                 unsigned long mem_size;
 492
 493                 /* compare results from other methods and take the greater */
 494                 if (ALT_MEM_K < EXT_MEM_K) {
 495                         mem_size = EXT_MEM_K;
 496                         who = "BIOS-88";
 497                 } else {
 498                         mem_size = ALT_MEM_K;
 499                         who = "BIOS-e801";
 500                 }
 501
 502                 e820.nr_map = 0;
 503                 add_memory_region(0, LOWMEMSIZE(), E820_RAM);
 504                 add_memory_region(HIGH_MEMORY, mem_size << 10, E820_RAM);
 505         }
 506         printk(KERN_INFO "BIOS-provided physical RAM map:\n");
 507         e820_print_map(who);
 508 }
 509 #endif
 510
 511 extern unsigned long xen_override_max_pfn;
 512
 513 void __init parse_memopt(char *p, char **from)
 514 {
 515         /*
 516          * mem=XXX[kKmM] limits kernel memory to XXX+1MB
 517          *
 518          * It would be more logical to count from 0 instead of from
 519          * HIGH_MEMORY, but we keep that for now for i386 compatibility.
 520          *
 521          * No support for custom mapping like i386.  The reason is
 522          * that we need to read the e820 map anyways to handle the
 523          * ACPI mappings in the direct map.  Also on x86-64 there
 524          * should be always a good e820 map. This is only an upper
 525          * limit, you cannot force usage of memory not in e820.
 526          *
 527          * -AK
 528                          */
 529         end_user_pfn = memparse(p, from) + HIGH_MEMORY;
 530         end_user_pfn >>= PAGE_SHIFT;
 531         xen_override_max_pfn = (unsigned long) end_user_pfn;
 532 }
 533