SAFE public projects git trees. - safe/jmp/linux-2.6/blob - arch/arm/mm/mm-armv.c

   1 /*
   2  *  linux/arch/arm/mm/mm-armv.c
   3  *
   4  *  Copyright (C) 1998-2002 Russell King
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  *  Page table sludge for ARM v3 and v4 processor architectures.
  11  */
  12 #include <linux/config.h>
  13 #include <linux/module.h>
  14 #include <linux/mm.h>
  15 #include <linux/init.h>
  16 #include <linux/bootmem.h>
  17 #include <linux/highmem.h>
  18 #include <linux/nodemask.h>
  19
  20 #include <asm/pgalloc.h>
  21 #include <asm/page.h>
  22 #include <asm/io.h>
  23 #include <asm/setup.h>
  24 #include <asm/tlbflush.h>
  25
  26 #include <asm/mach/map.h>
  27
  28 #define CPOLICY_UNCACHED        0
  29 #define CPOLICY_BUFFERED        1
  30 #define CPOLICY_WRITETHROUGH    2
  31 #define CPOLICY_WRITEBACK       3
  32 #define CPOLICY_WRITEALLOC      4
  33
  34 static unsigned int cachepolicy __initdata = CPOLICY_WRITEBACK;
  35 static unsigned int ecc_mask __initdata = 0;
  36 pgprot_t pgprot_kernel;
  37
  38 EXPORT_SYMBOL(pgprot_kernel);
  39
  40 struct cachepolicy {
  41         const char      policy[16];
  42         unsigned int    cr_mask;
  43         unsigned int    pmd;
  44         unsigned int    pte;
  45 };
  46
  47 static struct cachepolicy cache_policies[] __initdata = {
  48         {
  49                 .policy         = "uncached",
  50                 .cr_mask        = CR_W|CR_C,
  51                 .pmd            = PMD_SECT_UNCACHED,
  52                 .pte            = 0,
  53         }, {
  54                 .policy         = "buffered",
  55                 .cr_mask        = CR_C,
  56                 .pmd            = PMD_SECT_BUFFERED,
  57                 .pte            = PTE_BUFFERABLE,
  58         }, {
  59                 .policy         = "writethrough",
  60                 .cr_mask        = 0,
  61                 .pmd            = PMD_SECT_WT,
  62                 .pte            = PTE_CACHEABLE,
  63         }, {
  64                 .policy         = "writeback",
  65                 .cr_mask        = 0,
  66                 .pmd            = PMD_SECT_WB,
  67                 .pte            = PTE_BUFFERABLE|PTE_CACHEABLE,
  68         }, {
  69                 .policy         = "writealloc",
  70                 .cr_mask        = 0,
  71                 .pmd            = PMD_SECT_WBWA,
  72                 .pte            = PTE_BUFFERABLE|PTE_CACHEABLE,
  73         }
  74 };
  75
  76 /*
  77  * These are useful for identifing cache coherency
  78  * problems by allowing the cache or the cache and
  79  * writebuffer to be turned off.  (Note: the write
  80  * buffer should not be on and the cache off).
  81  */
  82 static void __init early_cachepolicy(char **p)
  83 {
  84         int i;
  85
  86         for (i = 0; i < ARRAY_SIZE(cache_policies); i++) {
  87                 int len = strlen(cache_policies[i].policy);
  88
  89                 if (memcmp(*p, cache_policies[i].policy, len) == 0) {
  90                         cachepolicy = i;
  91                         cr_alignment &= ~cache_policies[i].cr_mask;
  92                         cr_no_alignment &= ~cache_policies[i].cr_mask;
  93                         *p += len;
  94                         break;
  95                 }
  96         }
  97         if (i == ARRAY_SIZE(cache_policies))
  98                 printk(KERN_ERR "ERROR: unknown or unsupported cache policy\n");
  99         flush_cache_all();
 100         set_cr(cr_alignment);
 101 }
 102
 103 static void __init early_nocache(char **__unused)
 104 {
 105         char *p = "buffered";
 106         printk(KERN_WARNING "nocache is deprecated; use cachepolicy=%s\n", p);
 107         early_cachepolicy(&p);
 108 }
 109
 110 static void __init early_nowrite(char **__unused)
 111 {
 112         char *p = "uncached";
 113         printk(KERN_WARNING "nowb is deprecated; use cachepolicy=%s\n", p);
 114         early_cachepolicy(&p);
 115 }
 116
 117 static void __init early_ecc(char **p)
 118 {
 119         if (memcmp(*p, "on", 2) == 0) {
 120                 ecc_mask = PMD_PROTECTION;
 121                 *p += 2;
 122         } else if (memcmp(*p, "off", 3) == 0) {
 123                 ecc_mask = 0;
 124                 *p += 3;
 125         }
 126 }
 127
 128 __early_param("nocache", early_nocache);
 129 __early_param("nowb", early_nowrite);
 130 __early_param("cachepolicy=", early_cachepolicy);
 131 __early_param("ecc=", early_ecc);
 132
 133 static int __init noalign_setup(char *__unused)
 134 {
 135         cr_alignment &= ~CR_A;
 136         cr_no_alignment &= ~CR_A;
 137         set_cr(cr_alignment);
 138         return 1;
 139 }
 140
 141 __setup("noalign", noalign_setup);
 142
 143 #define FIRST_KERNEL_PGD_NR     (FIRST_USER_PGD_NR + USER_PTRS_PER_PGD)
 144
 145 /*
 146  * need to get a 16k page for level 1
 147  */
 148 pgd_t *get_pgd_slow(struct mm_struct *mm)
 149 {
 150         pgd_t *new_pgd, *init_pgd;
 151         pmd_t *new_pmd, *init_pmd;
 152         pte_t *new_pte, *init_pte;
 153
 154         new_pgd = (pgd_t *)__get_free_pages(GFP_KERNEL, 2);
 155         if (!new_pgd)
 156                 goto no_pgd;
 157
 158         memzero(new_pgd, FIRST_KERNEL_PGD_NR * sizeof(pgd_t));
 159
 160         init_pgd = pgd_offset_k(0);
 161
 162         if (!vectors_high()) {
 163                 /*
 164                  * This lock is here just to satisfy pmd_alloc and pte_lock
 165                  */
 166                 spin_lock(&mm->page_table_lock);
 167
 168                 /*
 169                  * On ARM, first page must always be allocated since it
 170                  * contains the machine vectors.
 171                  */
 172                 new_pmd = pmd_alloc(mm, new_pgd, 0);
 173                 if (!new_pmd)
 174                         goto no_pmd;
 175
 176                 new_pte = pte_alloc_map(mm, new_pmd, 0);
 177                 if (!new_pte)
 178                         goto no_pte;
 179
 180                 init_pmd = pmd_offset(init_pgd, 0);
 181                 init_pte = pte_offset_map_nested(init_pmd, 0);
 182                 set_pte(new_pte, *init_pte);
 183                 pte_unmap_nested(init_pte);
 184                 pte_unmap(new_pte);
 185
 186                 spin_unlock(&mm->page_table_lock);
 187         }
 188
 189         /*
 190          * Copy over the kernel and IO PGD entries
 191          */
 192         memcpy(new_pgd + FIRST_KERNEL_PGD_NR, init_pgd + FIRST_KERNEL_PGD_NR,
 193                        (PTRS_PER_PGD - FIRST_KERNEL_PGD_NR) * sizeof(pgd_t));
 194
 195         clean_dcache_area(new_pgd, PTRS_PER_PGD * sizeof(pgd_t));
 196
 197         return new_pgd;
 198
 199 no_pte:
 200         spin_unlock(&mm->page_table_lock);
 201         pmd_free(new_pmd);
 202         free_pages((unsigned long)new_pgd, 2);
 203         return NULL;
 204
 205 no_pmd:
 206         spin_unlock(&mm->page_table_lock);
 207         free_pages((unsigned long)new_pgd, 2);
 208         return NULL;
 209
 210 no_pgd:
 211         return NULL;
 212 }
 213
 214 void free_pgd_slow(pgd_t *pgd)
 215 {
 216         pmd_t *pmd;
 217         struct page *pte;
 218
 219         if (!pgd)
 220                 return;
 221
 222         /* pgd is always present and good */
 223         pmd = (pmd_t *)pgd;
 224         if (pmd_none(*pmd))
 225                 goto free;
 226         if (pmd_bad(*pmd)) {
 227                 pmd_ERROR(*pmd);
 228                 pmd_clear(pmd);
 229                 goto free;
 230         }
 231
 232         pte = pmd_page(*pmd);
 233         pmd_clear(pmd);
 234         dec_page_state(nr_page_table_pages);
 235         pte_free(pte);
 236         pmd_free(pmd);
 237 free:
 238         free_pages((unsigned long) pgd, 2);
 239 }
 240
 241 /*
 242  * Create a SECTION PGD between VIRT and PHYS in domain
 243  * DOMAIN with protection PROT.  This operates on half-
 244  * pgdir entry increments.
 245  */
 246 static inline void
 247 alloc_init_section(unsigned long virt, unsigned long phys, int prot)
 248 {
 249         pmd_t *pmdp;
 250
 251         pmdp = pmd_offset(pgd_offset_k(virt), virt);
 252         if (virt & (1 << 20))
 253                 pmdp++;
 254
 255         *pmdp = __pmd(phys | prot);
 256         flush_pmd_entry(pmdp);
 257 }
 258
 259 /*
 260  * Create a SUPER SECTION PGD between VIRT and PHYS with protection PROT
 261  */
 262 static inline void
 263 alloc_init_supersection(unsigned long virt, unsigned long phys, int prot)
 264 {
 265         int i;
 266
 267         for (i = 0; i < 16; i += 1) {
 268                 alloc_init_section(virt, phys & SUPERSECTION_MASK,
 269                                    prot | PMD_SECT_SUPER);
 270
 271                 virt += (PGDIR_SIZE / 2);
 272                 phys += (PGDIR_SIZE / 2);
 273         }
 274 }
 275
 276 /*
 277  * Add a PAGE mapping between VIRT and PHYS in domain
 278  * DOMAIN with protection PROT.  Note that due to the
 279  * way we map the PTEs, we must allocate two PTE_SIZE'd
 280  * blocks - one for the Linux pte table, and one for
 281  * the hardware pte table.
 282  */
 283 static inline void
 284 alloc_init_page(unsigned long virt, unsigned long phys, unsigned int prot_l1, pgprot_t prot)
 285 {
 286         pmd_t *pmdp;
 287         pte_t *ptep;
 288
 289         pmdp = pmd_offset(pgd_offset_k(virt), virt);
 290
 291         if (pmd_none(*pmdp)) {
 292                 unsigned long pmdval;
 293                 ptep = alloc_bootmem_low_pages(2 * PTRS_PER_PTE *
 294                                                sizeof(pte_t));
 295
 296                 pmdval = __pa(ptep) | prot_l1;
 297                 pmdp[0] = __pmd(pmdval);
 298                 pmdp[1] = __pmd(pmdval + 256 * sizeof(pte_t));
 299                 flush_pmd_entry(pmdp);
 300         }
 301         ptep = pte_offset_kernel(pmdp, virt);
 302
 303         set_pte(ptep, pfn_pte(phys >> PAGE_SHIFT, prot));
 304 }
 305
 306 /*
 307  * Clear any PGD mapping.  On a two-level page table system,
 308  * the clearance is done by the middle-level functions (pmd)
 309  * rather than the top-level (pgd) functions.
 310  */
 311 static inline void clear_mapping(unsigned long virt)
 312 {
 313         pmd_clear(pmd_offset(pgd_offset_k(virt), virt));
 314 }
 315
 316 struct mem_types {
 317         unsigned int    prot_pte;
 318         unsigned int    prot_l1;
 319         unsigned int    prot_sect;
 320         unsigned int    domain;
 321 };
 322
 323 static struct mem_types mem_types[] __initdata = {
 324         [MT_DEVICE] = {
 325                 .prot_pte  = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
 326                                 L_PTE_WRITE,
 327                 .prot_l1   = PMD_TYPE_TABLE,
 328                 .prot_sect = PMD_TYPE_SECT | PMD_SECT_UNCACHED |
 329                                 PMD_SECT_AP_WRITE,
 330                 .domain    = DOMAIN_IO,
 331         },
 332         [MT_CACHECLEAN] = {
 333                 .prot_sect = PMD_TYPE_SECT,
 334                 .domain    = DOMAIN_KERNEL,
 335         },
 336         [MT_MINICLEAN] = {
 337                 .prot_sect = PMD_TYPE_SECT | PMD_SECT_MINICACHE,
 338                 .domain    = DOMAIN_KERNEL,
 339         },
 340         [MT_LOW_VECTORS] = {
 341                 .prot_pte  = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
 342                                 L_PTE_EXEC,
 343                 .prot_l1   = PMD_TYPE_TABLE,
 344                 .domain    = DOMAIN_USER,
 345         },
 346         [MT_HIGH_VECTORS] = {
 347                 .prot_pte  = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
 348                                 L_PTE_USER | L_PTE_EXEC,
 349                 .prot_l1   = PMD_TYPE_TABLE,
 350                 .domain    = DOMAIN_USER,
 351         },
 352         [MT_MEMORY] = {
 353                 .prot_sect = PMD_TYPE_SECT | PMD_SECT_AP_WRITE,
 354                 .domain    = DOMAIN_KERNEL,
 355         },
 356         [MT_ROM] = {
 357                 .prot_sect = PMD_TYPE_SECT,
 358                 .domain    = DOMAIN_KERNEL,
 359         },
 360         [MT_IXP2000_DEVICE] = { /* IXP2400 requires XCB=101 for on-chip I/O */
 361                 .prot_pte  = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
 362                                 L_PTE_WRITE,
 363                 .prot_l1   = PMD_TYPE_TABLE,
 364                 .prot_sect = PMD_TYPE_SECT | PMD_SECT_UNCACHED |
 365                                 PMD_SECT_AP_WRITE | PMD_SECT_BUFFERABLE |
 366                                 PMD_SECT_TEX(1),
 367                 .domain    = DOMAIN_IO,
 368         }
 369 };
 370
 371 /*
 372  * Adjust the PMD section entries according to the CPU in use.
 373  */
 374 static void __init build_mem_type_table(void)
 375 {
 376         struct cachepolicy *cp;
 377         unsigned int cr = get_cr();
 378         int cpu_arch = cpu_architecture();
 379         int i;
 380
 381 #if defined(CONFIG_CPU_DCACHE_DISABLE)
 382         if (cachepolicy > CPOLICY_BUFFERED)
 383                 cachepolicy = CPOLICY_BUFFERED;
 384 #elif defined(CONFIG_CPU_DCACHE_WRITETHROUGH)
 385         if (cachepolicy > CPOLICY_WRITETHROUGH)
 386                 cachepolicy = CPOLICY_WRITETHROUGH;
 387 #endif
 388         if (cpu_arch < CPU_ARCH_ARMv5) {
 389                 if (cachepolicy >= CPOLICY_WRITEALLOC)
 390                         cachepolicy = CPOLICY_WRITEBACK;
 391                 ecc_mask = 0;
 392         }
 393
 394         if (cpu_arch <= CPU_ARCH_ARMv5) {
 395                 for (i = 0; i < ARRAY_SIZE(mem_types); i++) {
 396                         if (mem_types[i].prot_l1)
 397                                 mem_types[i].prot_l1 |= PMD_BIT4;
 398                         if (mem_types[i].prot_sect)
 399                                 mem_types[i].prot_sect |= PMD_BIT4;
 400                 }
 401         }
 402
 403         /*
 404          * ARMv6 and above have extended page tables.
 405          */
 406         if (cpu_arch >= CPU_ARCH_ARMv6 && (cr & CR_XP)) {
 407                 /*
 408                  * bit 4 becomes XN which we must clear for the
 409                  * kernel memory mapping.
 410                  */
 411                 mem_types[MT_MEMORY].prot_sect &= ~PMD_BIT4;
 412                 mem_types[MT_ROM].prot_sect &= ~PMD_BIT4;
 413                 /*
 414                  * Mark cache clean areas read only from SVC mode
 415                  * and no access from userspace.
 416                  */
 417                 mem_types[MT_MINICLEAN].prot_sect |= PMD_SECT_APX|PMD_SECT_AP_WRITE;
 418                 mem_types[MT_CACHECLEAN].prot_sect |= PMD_SECT_APX|PMD_SECT_AP_WRITE;
 419         }
 420
 421         cp = &cache_policies[cachepolicy];
 422
 423         if (cpu_arch >= CPU_ARCH_ARMv5) {
 424                 mem_types[MT_LOW_VECTORS].prot_pte |= cp->pte & PTE_CACHEABLE;
 425                 mem_types[MT_HIGH_VECTORS].prot_pte |= cp->pte & PTE_CACHEABLE;
 426         } else {
 427                 mem_types[MT_LOW_VECTORS].prot_pte |= cp->pte;
 428                 mem_types[MT_HIGH_VECTORS].prot_pte |= cp->pte;
 429                 mem_types[MT_MINICLEAN].prot_sect &= ~PMD_SECT_TEX(1);
 430         }
 431
 432         mem_types[MT_LOW_VECTORS].prot_l1 |= ecc_mask;
 433         mem_types[MT_HIGH_VECTORS].prot_l1 |= ecc_mask;
 434         mem_types[MT_MEMORY].prot_sect |= ecc_mask | cp->pmd;
 435         mem_types[MT_ROM].prot_sect |= cp->pmd;
 436
 437         for (i = 0; i < 16; i++) {
 438                 unsigned long v = pgprot_val(protection_map[i]);
 439                 v &= (~(PTE_BUFFERABLE|PTE_CACHEABLE)) | cp->pte;
 440                 protection_map[i] = __pgprot(v);
 441         }
 442
 443         pgprot_kernel = __pgprot(L_PTE_PRESENT | L_PTE_YOUNG |
 444                                  L_PTE_DIRTY | L_PTE_WRITE |
 445                                  L_PTE_EXEC | cp->pte);
 446
 447         switch (cp->pmd) {
 448         case PMD_SECT_WT:
 449                 mem_types[MT_CACHECLEAN].prot_sect |= PMD_SECT_WT;
 450                 break;
 451         case PMD_SECT_WB:
 452         case PMD_SECT_WBWA:
 453                 mem_types[MT_CACHECLEAN].prot_sect |= PMD_SECT_WB;
 454                 break;
 455         }
 456         printk("Memory policy: ECC %sabled, Data cache %s\n",
 457                 ecc_mask ? "en" : "dis", cp->policy);
 458 }
 459
 460 #define vectors_base()  (vectors_high() ? 0xffff0000 : 0)
 461
 462 /*
 463  * Create the page directory entries and any necessary
 464  * page tables for the mapping specified by `md'.  We
 465  * are able to cope here with varying sizes and address
 466  * offsets, and we take full advantage of sections and
 467  * supersections.
 468  */
 469 static void __init create_mapping(struct map_desc *md)
 470 {
 471         unsigned long virt, length;
 472         int prot_sect, prot_l1, domain;
 473         pgprot_t prot_pte;
 474         long off;
 475
 476         if (md->virtual != vectors_base() && md->virtual < TASK_SIZE) {
 477                 printk(KERN_WARNING "BUG: not creating mapping for "
 478                        "0x%08lx at 0x%08lx in user region\n",
 479                        md->physical, md->virtual);
 480                 return;
 481         }
 482
 483         if ((md->type == MT_DEVICE || md->type == MT_ROM) &&
 484             md->virtual >= PAGE_OFFSET && md->virtual < VMALLOC_END) {
 485                 printk(KERN_WARNING "BUG: mapping for 0x%08lx at 0x%08lx "
 486                        "overlaps vmalloc space\n",
 487                        md->physical, md->virtual);
 488         }
 489
 490         domain    = mem_types[md->type].domain;
 491         prot_pte  = __pgprot(mem_types[md->type].prot_pte);
 492         prot_l1   = mem_types[md->type].prot_l1 | PMD_DOMAIN(domain);
 493         prot_sect = mem_types[md->type].prot_sect | PMD_DOMAIN(domain);
 494
 495         virt   = md->virtual;
 496         off    = md->physical - virt;
 497         length = md->length;
 498
 499         if (mem_types[md->type].prot_l1 == 0 &&
 500             (virt & 0xfffff || (virt + off) & 0xfffff || (virt + length) & 0xfffff)) {
 501                 printk(KERN_WARNING "BUG: map for 0x%08lx at 0x%08lx can not "
 502                        "be mapped using pages, ignoring.\n",
 503                        md->physical, md->virtual);
 504                 return;
 505         }
 506
 507         while ((virt & 0xfffff || (virt + off) & 0xfffff) && length >= PAGE_SIZE) {
 508                 alloc_init_page(virt, virt + off, prot_l1, prot_pte);
 509
 510                 virt   += PAGE_SIZE;
 511                 length -= PAGE_SIZE;
 512         }
 513
 514         /* N.B. ARMv6 supersections are only defined to work with domain 0.
 515          *      Since domain assignments can in fact be arbitrary, the
 516          *      'domain == 0' check below is required to insure that ARMv6
 517          *      supersections are only allocated for domain 0 regardless
 518          *      of the actual domain assignments in use.
 519          */
 520         if (cpu_architecture() >= CPU_ARCH_ARMv6 && domain == 0) {
 521                 /* Align to supersection boundary */
 522                 while ((virt & ~SUPERSECTION_MASK || (virt + off) &
 523                         ~SUPERSECTION_MASK) && length >= (PGDIR_SIZE / 2)) {
 524                         alloc_init_section(virt, virt + off, prot_sect);
 525
 526                         virt   += (PGDIR_SIZE / 2);
 527                         length -= (PGDIR_SIZE / 2);
 528                 }
 529
 530                 while (length >= SUPERSECTION_SIZE) {
 531                         alloc_init_supersection(virt, virt + off, prot_sect);
 532
 533                         virt   += SUPERSECTION_SIZE;
 534                         length -= SUPERSECTION_SIZE;
 535                 }
 536         }
 537
 538         /*
 539          * A section mapping covers half a "pgdir" entry.
 540          */
 541         while (length >= (PGDIR_SIZE / 2)) {
 542                 alloc_init_section(virt, virt + off, prot_sect);
 543
 544                 virt   += (PGDIR_SIZE / 2);
 545                 length -= (PGDIR_SIZE / 2);
 546         }
 547
 548         while (length >= PAGE_SIZE) {
 549                 alloc_init_page(virt, virt + off, prot_l1, prot_pte);
 550
 551                 virt   += PAGE_SIZE;
 552                 length -= PAGE_SIZE;
 553         }
 554 }
 555
 556 /*
 557  * In order to soft-boot, we need to insert a 1:1 mapping in place of
 558  * the user-mode pages.  This will then ensure that we have predictable
 559  * results when turning the mmu off
 560  */
 561 void setup_mm_for_reboot(char mode)
 562 {
 563         unsigned long pmdval;
 564         pgd_t *pgd;
 565         pmd_t *pmd;
 566         int i;
 567         int cpu_arch = cpu_architecture();
 568
 569         if (current->mm && current->mm->pgd)
 570                 pgd = current->mm->pgd;
 571         else
 572                 pgd = init_mm.pgd;
 573
 574         for (i = 0; i < FIRST_USER_PGD_NR + USER_PTRS_PER_PGD; i++) {
 575                 pmdval = (i << PGDIR_SHIFT) |
 576                          PMD_SECT_AP_WRITE | PMD_SECT_AP_READ |
 577                          PMD_TYPE_SECT;
 578                 if (cpu_arch <= CPU_ARCH_ARMv5)
 579                         pmdval |= PMD_BIT4;
 580                 pmd = pmd_offset(pgd + i, i << PGDIR_SHIFT);
 581                 pmd[0] = __pmd(pmdval);
 582                 pmd[1] = __pmd(pmdval + (1 << (PGDIR_SHIFT - 1)));
 583                 flush_pmd_entry(pmd);
 584         }
 585 }
 586
 587 extern void _stext, _etext;
 588
 589 /*
 590  * Setup initial mappings.  We use the page we allocated for zero page to hold
 591  * the mappings, which will get overwritten by the vectors in traps_init().
 592  * The mappings must be in virtual address order.
 593  */
 594 void __init memtable_init(struct meminfo *mi)
 595 {
 596         struct map_desc *init_maps, *p, *q;
 597         unsigned long address = 0;
 598         int i;
 599
 600         build_mem_type_table();
 601
 602         init_maps = p = alloc_bootmem_low_pages(PAGE_SIZE);
 603
 604 #ifdef CONFIG_XIP_KERNEL
 605         p->physical   = CONFIG_XIP_PHYS_ADDR & PMD_MASK;
 606         p->virtual    = (unsigned long)&_stext & PMD_MASK;
 607         p->length     = ((unsigned long)&_etext - p->virtual + ~PMD_MASK) & PMD_MASK;
 608         p->type       = MT_ROM;
 609         p ++;
 610 #endif
 611
 612         for (i = 0; i < mi->nr_banks; i++) {
 613                 if (mi->bank[i].size == 0)
 614                         continue;
 615
 616                 p->physical   = mi->bank[i].start;
 617                 p->virtual    = __phys_to_virt(p->physical);
 618                 p->length     = mi->bank[i].size;
 619                 p->type       = MT_MEMORY;
 620                 p ++;
 621         }
 622
 623 #ifdef FLUSH_BASE
 624         p->physical   = FLUSH_BASE_PHYS;
 625         p->virtual    = FLUSH_BASE;
 626         p->length     = PGDIR_SIZE;
 627         p->type       = MT_CACHECLEAN;
 628         p ++;
 629 #endif
 630
 631 #ifdef FLUSH_BASE_MINICACHE
 632         p->physical   = FLUSH_BASE_PHYS + PGDIR_SIZE;
 633         p->virtual    = FLUSH_BASE_MINICACHE;
 634         p->length     = PGDIR_SIZE;
 635         p->type       = MT_MINICLEAN;
 636         p ++;
 637 #endif
 638
 639         /*
 640          * Go through the initial mappings, but clear out any
 641          * pgdir entries that are not in the description.
 642          */
 643         q = init_maps;
 644         do {
 645                 if (address < q->virtual || q == p) {
 646                         clear_mapping(address);
 647                         address += PGDIR_SIZE;
 648                 } else {
 649                         create_mapping(q);
 650
 651                         address = q->virtual + q->length;
 652                         address = (address + PGDIR_SIZE - 1) & PGDIR_MASK;
 653
 654                         q ++;
 655                 }
 656         } while (address != 0);
 657
 658         /*
 659          * Create a mapping for the machine vectors at the high-vectors
 660          * location (0xffff0000).  If we aren't using high-vectors, also
 661          * create a mapping at the low-vectors virtual address.
 662          */
 663         init_maps->physical   = virt_to_phys(init_maps);
 664         init_maps->virtual    = 0xffff0000;
 665         init_maps->length     = PAGE_SIZE;
 666         init_maps->type       = MT_HIGH_VECTORS;
 667         create_mapping(init_maps);
 668
 669         if (!vectors_high()) {
 670                 init_maps->virtual = 0;
 671                 init_maps->type = MT_LOW_VECTORS;
 672                 create_mapping(init_maps);
 673         }
 674
 675         flush_cache_all();
 676         flush_tlb_all();
 677 }
 678
 679 /*
 680  * Create the architecture specific mappings
 681  */
 682 void __init iotable_init(struct map_desc *io_desc, int nr)
 683 {
 684         int i;
 685
 686         for (i = 0; i < nr; i++)
 687                 create_mapping(io_desc + i);
 688 }
 689
 690 static inline void
 691 free_memmap(int node, unsigned long start_pfn, unsigned long end_pfn)
 692 {
 693         struct page *start_pg, *end_pg;
 694         unsigned long pg, pgend;
 695
 696         /*
 697          * Convert start_pfn/end_pfn to a struct page pointer.
 698          */
 699         start_pg = pfn_to_page(start_pfn);
 700         end_pg = pfn_to_page(end_pfn);
 701
 702         /*
 703          * Convert to physical addresses, and
 704          * round start upwards and end downwards.
 705          */
 706         pg = PAGE_ALIGN(__pa(start_pg));
 707         pgend = __pa(end_pg) & PAGE_MASK;
 708
 709         /*
 710          * If there are free pages between these,
 711          * free the section of the memmap array.
 712          */
 713         if (pg < pgend)
 714                 free_bootmem_node(NODE_DATA(node), pg, pgend - pg);
 715 }
 716
 717 static inline void free_unused_memmap_node(int node, struct meminfo *mi)
 718 {
 719         unsigned long bank_start, prev_bank_end = 0;
 720         unsigned int i;
 721
 722         /*
 723          * [FIXME] This relies on each bank being in address order.  This
 724          * may not be the case, especially if the user has provided the
 725          * information on the command line.
 726          */
 727         for (i = 0; i < mi->nr_banks; i++) {
 728                 if (mi->bank[i].size == 0 || mi->bank[i].node != node)
 729                         continue;
 730
 731                 bank_start = mi->bank[i].start >> PAGE_SHIFT;
 732                 if (bank_start < prev_bank_end) {
 733                         printk(KERN_ERR "MEM: unordered memory banks.  "
 734                                 "Not freeing memmap.\n");
 735                         break;
 736                 }
 737
 738                 /*
 739                  * If we had a previous bank, and there is a space
 740                  * between the current bank and the previous, free it.
 741                  */
 742                 if (prev_bank_end && prev_bank_end != bank_start)
 743                         free_memmap(node, prev_bank_end, bank_start);
 744
 745                 prev_bank_end = PAGE_ALIGN(mi->bank[i].start +
 746                                            mi->bank[i].size) >> PAGE_SHIFT;
 747         }
 748 }
 749
 750 /*
 751  * The mem_map array can get very big.  Free
 752  * the unused area of the memory map.
 753  */
 754 void __init create_memmap_holes(struct meminfo *mi)
 755 {
 756         int node;
 757
 758         for_each_online_node(node)
 759                 free_unused_memmap_node(node, mi);
 760 }