arch/arm/mm/mmu.c

   1 /*
   2  *  linux/arch/arm/mm/mmu.c
   3  *
   4  *  Copyright (C) 1995-2005 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 #include <linux/module.h>
  11 #include <linux/kernel.h>
  12 #include <linux/errno.h>
  13 #include <linux/init.h>
  14 #include <linux/mman.h>
  15 #include <linux/nodemask.h>
  16 #include <linux/memblock.h>
  17 #include <linux/fs.h>
  18 #include <linux/vmalloc.h>
  19
  20 #include <asm/cputype.h>
  21 #include <asm/sections.h>
  22 #include <asm/cachetype.h>
  23 #include <asm/setup.h>
  24 #include <asm/sizes.h>
  25 #include <asm/smp_plat.h>
  26 #include <asm/tlb.h>
  27 #include <asm/highmem.h>
  28 #include <asm/traps.h>
  29
  30 #include <asm/mach/arch.h>
  31 #include <asm/mach/map.h>
  32
  33 #include "mm.h"
  34
  35 /*
  36  * empty_zero_page is a special page that is used for
  37  * zero-initialized data and COW.
  38  */
  39 struct page *empty_zero_page;
  40 EXPORT_SYMBOL(empty_zero_page);
  41
  42 /*
  43  * The pmd table for the upper-most set of pages.
  44  */
  45 pmd_t *top_pmd;
  46
  47 #define CPOLICY_UNCACHED        0
  48 #define CPOLICY_BUFFERED        1
  49 #define CPOLICY_WRITETHROUGH    2
  50 #define CPOLICY_WRITEBACK       3
  51 #define CPOLICY_WRITEALLOC      4
  52
  53 static unsigned int cachepolicy __initdata = CPOLICY_WRITEBACK;
  54 static unsigned int ecc_mask __initdata = 0;
  55 pgprot_t pgprot_user;
  56 pgprot_t pgprot_kernel;
  57
  58 EXPORT_SYMBOL(pgprot_user);
  59 EXPORT_SYMBOL(pgprot_kernel);
  60
  61 struct cachepolicy {
  62         const char      policy[16];
  63         unsigned int    cr_mask;
  64         pmdval_t        pmd;
  65         pteval_t        pte;
  66 };
  67
  68 static struct cachepolicy cache_policies[] __initdata = {
  69         {
  70                 .policy         = "uncached",
  71                 .cr_mask        = CR_W|CR_C,
  72                 .pmd            = PMD_SECT_UNCACHED,
  73                 .pte            = L_PTE_MT_UNCACHED,
  74         }, {
  75                 .policy         = "buffered",
  76                 .cr_mask        = CR_C,
  77                 .pmd            = PMD_SECT_BUFFERED,
  78                 .pte            = L_PTE_MT_BUFFERABLE,
  79         }, {
  80                 .policy         = "writethrough",
  81                 .cr_mask        = 0,
  82                 .pmd            = PMD_SECT_WT,
  83                 .pte            = L_PTE_MT_WRITETHROUGH,
  84         }, {
  85                 .policy         = "writeback",
  86                 .cr_mask        = 0,
  87                 .pmd            = PMD_SECT_WB,
  88                 .pte            = L_PTE_MT_WRITEBACK,
  89         }, {
  90                 .policy         = "writealloc",
  91                 .cr_mask        = 0,
  92                 .pmd            = PMD_SECT_WBWA,
  93                 .pte            = L_PTE_MT_WRITEALLOC,
  94         }
  95 };
  96
  97 /*
  98  * These are useful for identifying cache coherency
  99  * problems by allowing the cache or the cache and
 100  * writebuffer to be turned off.  (Note: the write
 101  * buffer should not be on and the cache off).
 102  */
 103 static int __init early_cachepolicy(char *p)
 104 {
 105         int i;
 106
 107         for (i = 0; i < ARRAY_SIZE(cache_policies); i++) {
 108                 int len = strlen(cache_policies[i].policy);
 109
 110                 if (memcmp(p, cache_policies[i].policy, len) == 0) {
 111                         cachepolicy = i;
 112                         cr_alignment &= ~cache_policies[i].cr_mask;
 113                         cr_no_alignment &= ~cache_policies[i].cr_mask;
 114                         break;
 115                 }
 116         }
 117         if (i == ARRAY_SIZE(cache_policies))
 118                 printk(KERN_ERR "ERROR: unknown or unsupported cache policy\n");
 119         /*
 120          * This restriction is partly to do with the way we boot; it is
 121          * unpredictable to have memory mapped using two different sets of
 122          * memory attributes (shared, type, and cache attribs).  We can not
 123          * change these attributes once the initial assembly has setup the
 124          * page tables.
 125          */
 126         if (cpu_architecture() >= CPU_ARCH_ARMv6) {
 127                 printk(KERN_WARNING "Only cachepolicy=writeback supported on ARMv6 and later\n");
 128                 cachepolicy = CPOLICY_WRITEBACK;
 129         }
 130         flush_cache_all();
 131         set_cr(cr_alignment);
 132         return 0;
 133 }
 134 early_param("cachepolicy", early_cachepolicy);
 135
 136 static int __init early_nocache(char *__unused)
 137 {
 138         char *p = "buffered";
 139         printk(KERN_WARNING "nocache is deprecated; use cachepolicy=%s\n", p);
 140         early_cachepolicy(p);
 141         return 0;
 142 }
 143 early_param("nocache", early_nocache);
 144
 145 static int __init early_nowrite(char *__unused)
 146 {
 147         char *p = "uncached";
 148         printk(KERN_WARNING "nowb is deprecated; use cachepolicy=%s\n", p);
 149         early_cachepolicy(p);
 150         return 0;
 151 }
 152 early_param("nowb", early_nowrite);
 153
 154 #ifndef CONFIG_ARM_LPAE
 155 static int __init early_ecc(char *p)
 156 {
 157         if (memcmp(p, "on", 2) == 0)
 158                 ecc_mask = PMD_PROTECTION;
 159         else if (memcmp(p, "off", 3) == 0)
 160                 ecc_mask = 0;
 161         return 0;
 162 }
 163 early_param("ecc", early_ecc);
 164 #endif
 165
 166 static int __init noalign_setup(char *__unused)
 167 {
 168         cr_alignment &= ~CR_A;
 169         cr_no_alignment &= ~CR_A;
 170         set_cr(cr_alignment);
 171         return 1;
 172 }
 173 __setup("noalign", noalign_setup);
 174
 175 #ifndef CONFIG_SMP
 176 void adjust_cr(unsigned long mask, unsigned long set)
 177 {
 178         unsigned long flags;
 179
 180         mask &= ~CR_A;
 181
 182         set &= mask;
 183
 184         local_irq_save(flags);
 185
 186         cr_no_alignment = (cr_no_alignment & ~mask) | set;
 187         cr_alignment = (cr_alignment & ~mask) | set;
 188
 189         set_cr((get_cr() & ~mask) | set);
 190
 191         local_irq_restore(flags);
 192 }
 193 #endif
 194
 195 #define PROT_PTE_DEVICE         L_PTE_PRESENT|L_PTE_YOUNG|L_PTE_DIRTY|L_PTE_XN
 196 #define PROT_SECT_DEVICE        PMD_TYPE_SECT|PMD_SECT_AP_WRITE
 197
 198 static struct mem_type mem_types[] = {
 199         [MT_DEVICE] = {           /* Strongly ordered / ARMv6 shared device */
 200                 .prot_pte       = PROT_PTE_DEVICE | L_PTE_MT_DEV_SHARED |
 201                                   L_PTE_SHARED,
 202                 .prot_l1        = PMD_TYPE_TABLE,
 203                 .prot_sect      = PROT_SECT_DEVICE | PMD_SECT_S,
 204                 .domain         = DOMAIN_IO,
 205         },
 206         [MT_DEVICE_NONSHARED] = { /* ARMv6 non-shared device */
 207                 .prot_pte       = PROT_PTE_DEVICE | L_PTE_MT_DEV_NONSHARED,
 208                 .prot_l1        = PMD_TYPE_TABLE,
 209                 .prot_sect      = PROT_SECT_DEVICE,
 210                 .domain         = DOMAIN_IO,
 211         },
 212         [MT_DEVICE_CACHED] = {    /* ioremap_cached */
 213                 .prot_pte       = PROT_PTE_DEVICE | L_PTE_MT_DEV_CACHED,
 214                 .prot_l1        = PMD_TYPE_TABLE,
 215                 .prot_sect      = PROT_SECT_DEVICE | PMD_SECT_WB,
 216                 .domain         = DOMAIN_IO,
 217         },
 218         [MT_DEVICE_WC] = {      /* ioremap_wc */
 219                 .prot_pte       = PROT_PTE_DEVICE | L_PTE_MT_DEV_WC,
 220                 .prot_l1        = PMD_TYPE_TABLE,
 221                 .prot_sect      = PROT_SECT_DEVICE,
 222                 .domain         = DOMAIN_IO,
 223         },
 224         [MT_UNCACHED] = {
 225                 .prot_pte       = PROT_PTE_DEVICE,
 226                 .prot_l1        = PMD_TYPE_TABLE,
 227                 .prot_sect      = PMD_TYPE_SECT | PMD_SECT_XN,
 228                 .domain         = DOMAIN_IO,
 229         },
 230         [MT_CACHECLEAN] = {
 231                 .prot_sect = PMD_TYPE_SECT | PMD_SECT_XN,
 232                 .domain    = DOMAIN_KERNEL,
 233         },
 234 #ifndef CONFIG_ARM_LPAE
 235         [MT_MINICLEAN] = {
 236                 .prot_sect = PMD_TYPE_SECT | PMD_SECT_XN | PMD_SECT_MINICACHE,
 237                 .domain    = DOMAIN_KERNEL,
 238         },
 239 #endif
 240         [MT_LOW_VECTORS] = {
 241                 .prot_pte  = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
 242                                 L_PTE_RDONLY,
 243                 .prot_l1   = PMD_TYPE_TABLE,
 244                 .domain    = DOMAIN_USER,
 245         },
 246         [MT_HIGH_VECTORS] = {
 247                 .prot_pte  = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
 248                                 L_PTE_USER | L_PTE_RDONLY,
 249                 .prot_l1   = PMD_TYPE_TABLE,
 250                 .domain    = DOMAIN_USER,
 251         },
 252         [MT_MEMORY] = {
 253                 .prot_pte  = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY,
 254                 .prot_l1   = PMD_TYPE_TABLE,
 255                 .prot_sect = PMD_TYPE_SECT | PMD_SECT_AP_WRITE,
 256                 .domain    = DOMAIN_KERNEL,
 257         },
 258         [MT_ROM] = {
 259                 .prot_sect = PMD_TYPE_SECT,
 260                 .domain    = DOMAIN_KERNEL,
 261         },
 262         [MT_MEMORY_NONCACHED] = {
 263                 .prot_pte  = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
 264                                 L_PTE_MT_BUFFERABLE,
 265                 .prot_l1   = PMD_TYPE_TABLE,
 266                 .prot_sect = PMD_TYPE_SECT | PMD_SECT_AP_WRITE,
 267                 .domain    = DOMAIN_KERNEL,
 268         },
 269         [MT_MEMORY_DTCM] = {
 270                 .prot_pte  = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
 271                                 L_PTE_XN,
 272                 .prot_l1   = PMD_TYPE_TABLE,
 273                 .prot_sect = PMD_TYPE_SECT | PMD_SECT_XN,
 274                 .domain    = DOMAIN_KERNEL,
 275         },
 276         [MT_MEMORY_ITCM] = {
 277                 .prot_pte  = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY,
 278                 .prot_l1   = PMD_TYPE_TABLE,
 279                 .domain    = DOMAIN_KERNEL,
 280         },
 281         [MT_MEMORY_SO] = {
 282                 .prot_pte  = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
 283                                 L_PTE_MT_UNCACHED,
 284                 .prot_l1   = PMD_TYPE_TABLE,
 285                 .prot_sect = PMD_TYPE_SECT | PMD_SECT_AP_WRITE | PMD_SECT_S |
 286                                 PMD_SECT_UNCACHED | PMD_SECT_XN,
 287                 .domain    = DOMAIN_KERNEL,
 288         },
 289         [MT_MEMORY_DMA_READY] = {
 290                 .prot_pte  = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY,
 291                 .prot_l1   = PMD_TYPE_TABLE,
 292                 .domain    = DOMAIN_KERNEL,
 293         },
 294 };
 295
 296 const struct mem_type *get_mem_type(unsigned int type)
 297 {
 298         return type < ARRAY_SIZE(mem_types) ? &mem_types[type] : NULL;
 299 }
 300 EXPORT_SYMBOL(get_mem_type);
 301
 302 /*
 303  * If the system supports huge pages and we are running with short descriptors,
 304  * then compute the pmd and linux pte prot values for a huge page.
 305  *
 306  * These values are used by both the HugeTLB and THP code.
 307  */
 308 #if defined(CONFIG_SYS_SUPPORTS_HUGETLBFS) && !defined(CONFIG_ARM_LPAE)
 309 pmdval_t arm_hugepmdprotval;
 310 EXPORT_SYMBOL(arm_hugepmdprotval);
 311
 312 pteval_t arm_hugepteprotval;
 313 EXPORT_SYMBOL(arm_hugepteprotval);
 314 #endif
 315
 316
 317 /*
 318  * Adjust the PMD section entries according to the CPU in use.
 319  */
 320 static void __init build_mem_type_table(void)
 321 {
 322         struct cachepolicy *cp;
 323         unsigned int cr = get_cr();
 324         pteval_t user_pgprot, kern_pgprot, vecs_pgprot;
 325         int cpu_arch = cpu_architecture();
 326         int i;
 327
 328         if (cpu_arch < CPU_ARCH_ARMv6) {
 329 #if defined(CONFIG_CPU_DCACHE_DISABLE)
 330                 if (cachepolicy > CPOLICY_BUFFERED)
 331                         cachepolicy = CPOLICY_BUFFERED;
 332 #elif defined(CONFIG_CPU_DCACHE_WRITETHROUGH)
 333                 if (cachepolicy > CPOLICY_WRITETHROUGH)
 334                         cachepolicy = CPOLICY_WRITETHROUGH;
 335 #endif
 336         }
 337         if (cpu_arch < CPU_ARCH_ARMv5) {
 338                 if (cachepolicy >= CPOLICY_WRITEALLOC)
 339                         cachepolicy = CPOLICY_WRITEBACK;
 340                 ecc_mask = 0;
 341         }
 342         if (is_smp())
 343                 cachepolicy = CPOLICY_WRITEALLOC;
 344
 345         /*
 346          * Strip out features not present on earlier architectures.
 347          * Pre-ARMv5 CPUs don't have TEX bits.  Pre-ARMv6 CPUs or those
 348          * without extended page tables don't have the 'Shared' bit.
 349          */
 350         if (cpu_arch < CPU_ARCH_ARMv5)
 351                 for (i = 0; i < ARRAY_SIZE(mem_types); i++)
 352                         mem_types[i].prot_sect &= ~PMD_SECT_TEX(7);
 353         if ((cpu_arch < CPU_ARCH_ARMv6 || !(cr & CR_XP)) && !cpu_is_xsc3())
 354                 for (i = 0; i < ARRAY_SIZE(mem_types); i++)
 355                         mem_types[i].prot_sect &= ~PMD_SECT_S;
 356
 357         /*
 358          * ARMv5 and lower, bit 4 must be set for page tables (was: cache
 359          * "update-able on write" bit on ARM610).  However, Xscale and
 360          * Xscale3 require this bit to be cleared.
 361          */
 362         if (cpu_is_xscale() || cpu_is_xsc3()) {
 363                 for (i = 0; i < ARRAY_SIZE(mem_types); i++) {
 364                         mem_types[i].prot_sect &= ~PMD_BIT4;
 365                         mem_types[i].prot_l1 &= ~PMD_BIT4;
 366                 }
 367         } else if (cpu_arch < CPU_ARCH_ARMv6) {
 368                 for (i = 0; i < ARRAY_SIZE(mem_types); i++) {
 369                         if (mem_types[i].prot_l1)
 370                                 mem_types[i].prot_l1 |= PMD_BIT4;
 371                         if (mem_types[i].prot_sect)
 372                                 mem_types[i].prot_sect |= PMD_BIT4;
 373                 }
 374         }
 375
 376         /*
 377          * Mark the device areas according to the CPU/architecture.
 378          */
 379         if (cpu_is_xsc3() || (cpu_arch >= CPU_ARCH_ARMv6 && (cr & CR_XP))) {
 380                 if (!cpu_is_xsc3()) {
 381                         /*
 382                          * Mark device regions on ARMv6+ as execute-never
 383                          * to prevent speculative instruction fetches.
 384                          */
 385                         mem_types[MT_DEVICE].prot_sect |= PMD_SECT_XN;
 386                         mem_types[MT_DEVICE_NONSHARED].prot_sect |= PMD_SECT_XN;
 387                         mem_types[MT_DEVICE_CACHED].prot_sect |= PMD_SECT_XN;
 388                         mem_types[MT_DEVICE_WC].prot_sect |= PMD_SECT_XN;
 389                 }
 390                 if (cpu_arch >= CPU_ARCH_ARMv7 && (cr & CR_TRE)) {
 391                         /*
 392                          * For ARMv7 with TEX remapping,
 393                          * - shared device is SXCB=1100
 394                          * - nonshared device is SXCB=0100
 395                          * - write combine device mem is SXCB=0001
 396                          * (Uncached Normal memory)
 397                          */
 398                         mem_types[MT_DEVICE].prot_sect |= PMD_SECT_TEX(1);
 399                         mem_types[MT_DEVICE_NONSHARED].prot_sect |= PMD_SECT_TEX(1);
 400                         mem_types[MT_DEVICE_WC].prot_sect |= PMD_SECT_BUFFERABLE;
 401                 } else if (cpu_is_xsc3()) {
 402                         /*
 403                          * For Xscale3,
 404                          * - shared device is TEXCB=00101
 405                          * - nonshared device is TEXCB=01000
 406                          * - write combine device mem is TEXCB=00100
 407                          * (Inner/Outer Uncacheable in xsc3 parlance)
 408                          */
 409                         mem_types[MT_DEVICE].prot_sect |= PMD_SECT_TEX(1) | PMD_SECT_BUFFERED;
 410                         mem_types[MT_DEVICE_NONSHARED].prot_sect |= PMD_SECT_TEX(2);
 411                         mem_types[MT_DEVICE_WC].prot_sect |= PMD_SECT_TEX(1);
 412                 } else {
 413                         /*
 414                          * For ARMv6 and ARMv7 without TEX remapping,
 415                          * - shared device is TEXCB=00001
 416                          * - nonshared device is TEXCB=01000
 417                          * - write combine device mem is TEXCB=00100
 418                          * (Uncached Normal in ARMv6 parlance).
 419                          */
 420                         mem_types[MT_DEVICE].prot_sect |= PMD_SECT_BUFFERED;
 421                         mem_types[MT_DEVICE_NONSHARED].prot_sect |= PMD_SECT_TEX(2);
 422                         mem_types[MT_DEVICE_WC].prot_sect |= PMD_SECT_TEX(1);
 423                 }
 424         } else {
 425                 /*
 426                  * On others, write combining is "Uncached/Buffered"
 427                  */
 428                 mem_types[MT_DEVICE_WC].prot_sect |= PMD_SECT_BUFFERABLE;
 429         }
 430
 431         /*
 432          * Now deal with the memory-type mappings
 433          */
 434         cp = &cache_policies[cachepolicy];
 435         vecs_pgprot = kern_pgprot = user_pgprot = cp->pte;
 436
 437         /*
 438          * Only use write-through for non-SMP systems
 439          */
 440         if (!is_smp() && cpu_arch >= CPU_ARCH_ARMv5 && cachepolicy > CPOLICY_WRITETHROUGH)
 441                 vecs_pgprot = cache_policies[CPOLICY_WRITETHROUGH].pte;
 442
 443         /*
 444          * Enable CPU-specific coherency if supported.
 445          * (Only available on XSC3 at the moment.)
 446          */
 447         if (arch_is_coherent() && cpu_is_xsc3()) {
 448                 mem_types[MT_MEMORY].prot_sect |= PMD_SECT_S;
 449                 mem_types[MT_MEMORY].prot_pte |= L_PTE_SHARED;
 450                 mem_types[MT_MEMORY_DMA_READY].prot_pte |= L_PTE_SHARED;
 451                 mem_types[MT_MEMORY_NONCACHED].prot_sect |= PMD_SECT_S;
 452                 mem_types[MT_MEMORY_NONCACHED].prot_pte |= L_PTE_SHARED;
 453         }
 454         /*
 455          * ARMv6 and above have extended page tables.
 456          */
 457         if (cpu_arch >= CPU_ARCH_ARMv6 && (cr & CR_XP)) {
 458 #ifndef CONFIG_ARM_LPAE
 459                 /*
 460                  * Mark cache clean areas and XIP ROM read only
 461                  * from SVC mode and no access from userspace.
 462                  */
 463                 mem_types[MT_ROM].prot_sect |= PMD_SECT_APX|PMD_SECT_AP_WRITE;
 464                 mem_types[MT_MINICLEAN].prot_sect |= PMD_SECT_APX|PMD_SECT_AP_WRITE;
 465                 mem_types[MT_CACHECLEAN].prot_sect |= PMD_SECT_APX|PMD_SECT_AP_WRITE;
 466 #endif
 467
 468                 if (is_smp()) {
 469                         /*
 470                          * Mark memory with the "shared" attribute
 471                          * for SMP systems
 472                          */
 473                         user_pgprot |= L_PTE_SHARED;
 474                         kern_pgprot |= L_PTE_SHARED;
 475                         vecs_pgprot |= L_PTE_SHARED;
 476                         mem_types[MT_DEVICE_WC].prot_sect |= PMD_SECT_S;
 477                         mem_types[MT_DEVICE_WC].prot_pte |= L_PTE_SHARED;
 478                         mem_types[MT_DEVICE_CACHED].prot_sect |= PMD_SECT_S;
 479                         mem_types[MT_DEVICE_CACHED].prot_pte |= L_PTE_SHARED;
 480                         mem_types[MT_MEMORY].prot_sect |= PMD_SECT_S;
 481                         mem_types[MT_MEMORY].prot_pte |= L_PTE_SHARED;
 482                         mem_types[MT_MEMORY_DMA_READY].prot_pte |= L_PTE_SHARED;
 483                         mem_types[MT_MEMORY_NONCACHED].prot_sect |= PMD_SECT_S;
 484                         mem_types[MT_MEMORY_NONCACHED].prot_pte |= L_PTE_SHARED;
 485                 }
 486         }
 487
 488         /*
 489          * Non-cacheable Normal - intended for memory areas that must
 490          * not cause dirty cache line writebacks when used
 491          */
 492         if (cpu_arch >= CPU_ARCH_ARMv6) {
 493                 if (cpu_arch >= CPU_ARCH_ARMv7 && (cr & CR_TRE)) {
 494                         /* Non-cacheable Normal is XCB = 001 */
 495                         mem_types[MT_MEMORY_NONCACHED].prot_sect |=
 496                                 PMD_SECT_BUFFERED;
 497                 } else {
 498                         /* For both ARMv6 and non-TEX-remapping ARMv7 */
 499                         mem_types[MT_MEMORY_NONCACHED].prot_sect |=
 500                                 PMD_SECT_TEX(1);
 501                 }
 502         } else {
 503                 mem_types[MT_MEMORY_NONCACHED].prot_sect |= PMD_SECT_BUFFERABLE;
 504         }
 505
 506 #ifdef CONFIG_ARM_LPAE
 507         /*
 508          * Do not generate access flag faults for the kernel mappings.
 509          */
 510         for (i = 0; i < ARRAY_SIZE(mem_types); i++) {
 511                 mem_types[i].prot_pte |= PTE_EXT_AF;
 512                 mem_types[i].prot_sect |= PMD_SECT_AF;
 513         }
 514         kern_pgprot |= PTE_EXT_AF;
 515         vecs_pgprot |= PTE_EXT_AF;
 516 #endif
 517
 518         for (i = 0; i < 16; i++) {
 519                 pteval_t v = pgprot_val(protection_map[i]);
 520                 protection_map[i] = __pgprot(v | user_pgprot);
 521         }
 522
 523         mem_types[MT_LOW_VECTORS].prot_pte |= vecs_pgprot;
 524         mem_types[MT_HIGH_VECTORS].prot_pte |= vecs_pgprot;
 525
 526         pgprot_user   = __pgprot(L_PTE_PRESENT | L_PTE_YOUNG | user_pgprot);
 527         pgprot_kernel = __pgprot(L_PTE_PRESENT | L_PTE_YOUNG |
 528                                  L_PTE_DIRTY | kern_pgprot);
 529
 530         mem_types[MT_LOW_VECTORS].prot_l1 |= ecc_mask;
 531         mem_types[MT_HIGH_VECTORS].prot_l1 |= ecc_mask;
 532         mem_types[MT_MEMORY].prot_sect |= ecc_mask | cp->pmd;
 533         mem_types[MT_MEMORY].prot_pte |= kern_pgprot;
 534         mem_types[MT_MEMORY_DMA_READY].prot_pte |= kern_pgprot;
 535         mem_types[MT_MEMORY_NONCACHED].prot_sect |= ecc_mask;
 536         mem_types[MT_ROM].prot_sect |= cp->pmd;
 537
 538         switch (cp->pmd) {
 539         case PMD_SECT_WT:
 540                 mem_types[MT_CACHECLEAN].prot_sect |= PMD_SECT_WT;
 541                 break;
 542         case PMD_SECT_WB:
 543         case PMD_SECT_WBWA:
 544                 mem_types[MT_CACHECLEAN].prot_sect |= PMD_SECT_WB;
 545                 break;
 546         }
 547         printk("Memory policy: ECC %sabled, Data cache %s\n",
 548                 ecc_mask ? "en" : "dis", cp->policy);
 549
 550         for (i = 0; i < ARRAY_SIZE(mem_types); i++) {
 551                 struct mem_type *t = &mem_types[i];
 552                 if (t->prot_l1)
 553                         t->prot_l1 |= PMD_DOMAIN(t->domain);
 554                 if (t->prot_sect)
 555                         t->prot_sect |= PMD_DOMAIN(t->domain);
 556         }
 557
 558 #if defined(CONFIG_SYS_SUPPORTS_HUGETLBFS) && !defined(CONFIG_ARM_LPAE)
 559         /*
 560          * we assume all huge pages are user pages and that hardware access
 561          * flag updates are disabled (i.e. SCTLR.AFE == 0b).
 562          */
 563         arm_hugepteprotval = mem_types[MT_MEMORY].prot_pte | L_PTE_USER | L_PTE_VALID;
 564
 565         arm_hugepmdprotval = mem_types[MT_MEMORY].prot_sect | PMD_SECT_AP_READ
 566                                 | PMD_SECT_nG;
 567
 568         /* HACK: make huge pages WT
 569          * XXX: mm will not know nothing about this..
 570          * FIXME: should only do it on Cortex-A8 or below */
 571         arm_hugepmdprotval &= ~(PMD_SECT_WB | PMD_SECT_TEX(1));
 572         arm_hugepmdprotval |= PMD_SECT_WT;
 573 #endif
 574
 575 }
 576
 577 #ifdef CONFIG_ARM_DMA_MEM_BUFFERABLE
 578 pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
 579                               unsigned long size, pgprot_t vma_prot)
 580 {
 581         if (!pfn_valid(pfn))
 582                 return pgprot_noncached(vma_prot);
 583         else if (file->f_flags & O_SYNC)
 584                 return pgprot_writecombine(vma_prot);
 585         return vma_prot;
 586 }
 587 EXPORT_SYMBOL(phys_mem_access_prot);
 588 #endif
 589
 590 #define vectors_base()  (vectors_high() ? 0xffff0000 : 0)
 591
 592 static void __init *early_alloc_aligned(unsigned long sz, unsigned long align)
 593 {
 594         void *ptr = __va(memblock_alloc(sz, align));
 595         memset(ptr, 0, sz);
 596         return ptr;
 597 }
 598
 599 static void __init *early_alloc(unsigned long sz)
 600 {
 601         return early_alloc_aligned(sz, sz);
 602 }
 603
 604 static pte_t * __init early_pte_alloc(pmd_t *pmd, unsigned long addr, unsigned long prot)
 605 {
 606         if (pmd_none(*pmd)) {
 607                 pte_t *pte = early_alloc(PTE_HWTABLE_OFF + PTE_HWTABLE_SIZE);
 608                 __pmd_populate(pmd, __pa(pte), prot);
 609         }
 610         BUG_ON(pmd_bad(*pmd));
 611         return pte_offset_kernel(pmd, addr);
 612 }
 613
 614 static void __init alloc_init_pte(pmd_t *pmd, unsigned long addr,
 615                                   unsigned long end, unsigned long pfn,
 616                                   const struct mem_type *type)
 617 {
 618         pte_t *pte = early_pte_alloc(pmd, addr, type->prot_l1);
 619         do {
 620                 set_pte_ext(pte, pfn_pte(pfn, __pgprot(type->prot_pte)), 0);
 621                 pfn++;
 622         } while (pte++, addr += PAGE_SIZE, addr != end);
 623 }
 624
 625 static void __init alloc_init_section(pud_t *pud, unsigned long addr,
 626                                       unsigned long end, phys_addr_t phys,
 627                                       const struct mem_type *type)
 628 {
 629         pmd_t *pmd = pmd_offset(pud, addr);
 630
 631         /*
 632          * Try a section mapping - end, addr and phys must all be aligned
 633          * to a section boundary.  Note that PMDs refer to the individual
 634          * L1 entries, whereas PGDs refer to a group of L1 entries making
 635          * up one logical pointer to an L2 table.
 636          */
 637         if (type->prot_sect && ((addr | end | phys) & ~SECTION_MASK) == 0) {
 638                 pmd_t *p = pmd;
 639
 640 #ifndef CONFIG_ARM_LPAE
 641                 if (addr & SECTION_SIZE)
 642                         pmd++;
 643 #endif
 644
 645                 do {
 646                         *pmd = __pmd(phys | type->prot_sect);
 647                         phys += SECTION_SIZE;
 648                 } while (pmd++, addr += SECTION_SIZE, addr != end);
 649
 650                 flush_pmd_entry(p);
 651         } else {
 652                 /*
 653                  * No need to loop; pte's aren't interested in the
 654                  * individual L1 entries.
 655                  */
 656                 alloc_init_pte(pmd, addr, end, __phys_to_pfn(phys), type);
 657         }
 658 }
 659
 660 static void alloc_init_pud(pgd_t *pgd, unsigned long addr, unsigned long end,
 661         unsigned long phys, const struct mem_type *type)
 662 {
 663         pud_t *pud = pud_offset(pgd, addr);
 664         unsigned long next;
 665
 666         do {
 667                 next = pud_addr_end(addr, end);
 668                 alloc_init_section(pud, addr, next, phys, type);
 669                 phys += next - addr;
 670         } while (pud++, addr = next, addr != end);
 671 }
 672
 673 #ifndef CONFIG_ARM_LPAE
 674 static void __init create_36bit_mapping(struct map_desc *md,
 675                                         const struct mem_type *type)
 676 {
 677         unsigned long addr, length, end;
 678         phys_addr_t phys;
 679         pgd_t *pgd;
 680
 681         addr = md->virtual;
 682         phys = __pfn_to_phys(md->pfn);
 683         length = PAGE_ALIGN(md->length);
 684
 685         if (!(cpu_architecture() >= CPU_ARCH_ARMv6 || cpu_is_xsc3())) {
 686                 printk(KERN_ERR "MM: CPU does not support supersection "
 687                        "mapping for 0x%08llx at 0x%08lx\n",
 688                        (long long)__pfn_to_phys((u64)md->pfn), addr);
 689                 return;
 690         }
 691
 692         /* N.B. ARMv6 supersections are only defined to work with domain 0.
 693          *      Since domain assignments can in fact be arbitrary, the
 694          *      'domain == 0' check below is required to insure that ARMv6
 695          *      supersections are only allocated for domain 0 regardless
 696          *      of the actual domain assignments in use.
 697          */
 698         if (type->domain) {
 699                 printk(KERN_ERR "MM: invalid domain in supersection "
 700                        "mapping for 0x%08llx at 0x%08lx\n",
 701                        (long long)__pfn_to_phys((u64)md->pfn), addr);
 702                 return;
 703         }
 704
 705         if ((addr | length | __pfn_to_phys(md->pfn)) & ~SUPERSECTION_MASK) {
 706                 printk(KERN_ERR "MM: cannot create mapping for 0x%08llx"
 707                        " at 0x%08lx invalid alignment\n",
 708                        (long long)__pfn_to_phys((u64)md->pfn), addr);
 709                 return;
 710         }
 711
 712         /*
 713          * Shift bits [35:32] of address into bits [23:20] of PMD
 714          * (See ARMv6 spec).
 715          */
 716         phys |= (((md->pfn >> (32 - PAGE_SHIFT)) & 0xF) << 20);
 717
 718         pgd = pgd_offset_k(addr);
 719         end = addr + length;
 720         do {
 721                 pud_t *pud = pud_offset(pgd, addr);
 722                 pmd_t *pmd = pmd_offset(pud, addr);
 723                 int i;
 724
 725                 for (i = 0; i < 16; i++)
 726                         *pmd++ = __pmd(phys | type->prot_sect | PMD_SECT_SUPER);
 727
 728                 addr += SUPERSECTION_SIZE;
 729                 phys += SUPERSECTION_SIZE;
 730                 pgd += SUPERSECTION_SIZE >> PGDIR_SHIFT;
 731         } while (addr != end);
 732 }
 733 #endif  /* !CONFIG_ARM_LPAE */
 734
 735 /*
 736  * Create the page directory entries and any necessary
 737  * page tables for the mapping specified by `md'.  We
 738  * are able to cope here with varying sizes and address
 739  * offsets, and we take full advantage of sections and
 740  * supersections.
 741  */
 742 static void __init create_mapping(struct map_desc *md)
 743 {
 744         unsigned long addr, length, end;
 745         phys_addr_t phys;
 746         const struct mem_type *type;
 747         pgd_t *pgd;
 748
 749         if (md->virtual != vectors_base() && md->virtual < TASK_SIZE) {
 750                 printk(KERN_WARNING "BUG: not creating mapping for 0x%08llx"
 751                        " at 0x%08lx in user region\n",
 752                        (long long)__pfn_to_phys((u64)md->pfn), md->virtual);
 753                 return;
 754         }
 755
 756         if ((md->type == MT_DEVICE || md->type == MT_ROM) &&
 757             md->virtual >= PAGE_OFFSET &&
 758             (md->virtual < VMALLOC_START || md->virtual >= VMALLOC_END)) {
 759                 printk(KERN_WARNING "BUG: mapping for 0x%08llx"
 760                        " at 0x%08lx out of vmalloc space\n",
 761                        (long long)__pfn_to_phys((u64)md->pfn), md->virtual);
 762         }
 763
 764         type = &mem_types[md->type];
 765
 766 #ifndef CONFIG_ARM_LPAE
 767         /*
 768          * Catch 36-bit addresses
 769          */
 770         if (md->pfn >= 0x100000) {
 771                 create_36bit_mapping(md, type);
 772                 return;
 773         }
 774 #endif
 775
 776         addr = md->virtual & PAGE_MASK;
 777         phys = __pfn_to_phys(md->pfn);
 778         length = PAGE_ALIGN(md->length + (md->virtual & ~PAGE_MASK));
 779
 780         if (type->prot_l1 == 0 && ((addr | phys | length) & ~SECTION_MASK)) {
 781                 printk(KERN_WARNING "BUG: map for 0x%08llx at 0x%08lx can not "
 782                        "be mapped using pages, ignoring.\n",
 783                        (long long)__pfn_to_phys(md->pfn), addr);
 784                 return;
 785         }
 786
 787         pgd = pgd_offset_k(addr);
 788         end = addr + length;
 789         do {
 790                 unsigned long next = pgd_addr_end(addr, end);
 791
 792                 alloc_init_pud(pgd, addr, next, phys, type);
 793
 794                 phys += next - addr;
 795                 addr = next;
 796         } while (pgd++, addr != end);
 797 }
 798
 799 /*
 800  * Create the architecture specific mappings
 801  */
 802 void __init iotable_init(struct map_desc *io_desc, int nr)
 803 {
 804         struct map_desc *md;
 805         struct vm_struct *vm;
 806
 807         if (!nr)
 808                 return;
 809
 810         vm = early_alloc_aligned(sizeof(*vm) * nr, __alignof__(*vm));
 811
 812         for (md = io_desc; nr; md++, nr--) {
 813                 create_mapping(md);
 814                 vm->addr = (void *)(md->virtual & PAGE_MASK);
 815                 vm->size = PAGE_ALIGN(md->length + (md->virtual & ~PAGE_MASK));
 816                 vm->phys_addr = __pfn_to_phys(md->pfn);
 817                 vm->flags = VM_IOREMAP | VM_ARM_STATIC_MAPPING;
 818                 vm->flags |= VM_ARM_MTYPE(md->type);
 819                 vm->caller = iotable_init;
 820                 vm_area_add_early(vm++);
 821         }
 822 }
 823
 824 static void * __initdata vmalloc_min =
 825         (void *)(VMALLOC_END - (240 << 20) - VMALLOC_OFFSET);
 826
 827 /*
 828  * vmalloc=size forces the vmalloc area to be exactly 'size'
 829  * bytes. This can be used to increase (or decrease) the vmalloc
 830  * area - the default is 240m.
 831  */
 832 static int __init early_vmalloc(char *arg)
 833 {
 834         unsigned long vmalloc_reserve = memparse(arg, NULL);
 835
 836         if (vmalloc_reserve < SZ_16M) {
 837                 vmalloc_reserve = SZ_16M;
 838                 printk(KERN_WARNING
 839                         "vmalloc area too small, limiting to %luMB\n",
 840                         vmalloc_reserve >> 20);
 841         }
 842
 843         if (vmalloc_reserve > VMALLOC_END - (PAGE_OFFSET + SZ_32M)) {
 844                 vmalloc_reserve = VMALLOC_END - (PAGE_OFFSET + SZ_32M);
 845                 printk(KERN_WARNING
 846                         "vmalloc area is too big, limiting to %luMB\n",
 847                         vmalloc_reserve >> 20);
 848         }
 849
 850         vmalloc_min = (void *)(VMALLOC_END - vmalloc_reserve);
 851         return 0;
 852 }
 853 early_param("vmalloc", early_vmalloc);
 854
 855 phys_addr_t arm_lowmem_limit __initdata = 0;
 856
 857 void __init sanity_check_meminfo(void)
 858 {
 859         int i, j, highmem = 0;
 860
 861         for (i = 0, j = 0; i < meminfo.nr_banks; i++) {
 862                 struct membank *bank = &meminfo.bank[j];
 863                 *bank = meminfo.bank[i];
 864
 865                 if (bank->start > ULONG_MAX)
 866                         highmem = 1;
 867
 868 #ifdef CONFIG_HIGHMEM
 869                 if (__va(bank->start) >= vmalloc_min ||
 870                     __va(bank->start) < (void *)PAGE_OFFSET)
 871                         highmem = 1;
 872
 873                 bank->highmem = highmem;
 874
 875                 /*
 876                  * Split those memory banks which are partially overlapping
 877                  * the vmalloc area greatly simplifying things later.
 878                  */
 879                 if (!highmem && __va(bank->start) < vmalloc_min &&
 880                     bank->size > vmalloc_min - __va(bank->start)) {
 881                         if (meminfo.nr_banks >= NR_BANKS) {
 882                                 printk(KERN_CRIT "NR_BANKS too low, "
 883                                                  "ignoring high memory\n");
 884                         } else {
 885                                 memmove(bank + 1, bank,
 886                                         (meminfo.nr_banks - i) * sizeof(*bank));
 887                                 meminfo.nr_banks++;
 888                                 i++;
 889                                 bank[1].size -= vmalloc_min - __va(bank->start);
 890                                 bank[1].start = __pa(vmalloc_min - 1) + 1;
 891                                 bank[1].highmem = highmem = 1;
 892                                 j++;
 893                         }
 894                         bank->size = vmalloc_min - __va(bank->start);
 895                 }
 896 #else
 897                 bank->highmem = highmem;
 898
 899                 /*
 900                  * Highmem banks not allowed with !CONFIG_HIGHMEM.
 901                  */
 902                 if (highmem) {
 903                         printk(KERN_NOTICE "Ignoring RAM at %.8llx-%.8llx "
 904                                "(!CONFIG_HIGHMEM).\n",
 905                                (unsigned long long)bank->start,
 906                                (unsigned long long)bank->start + bank->size - 1);
 907                         continue;
 908                 }
 909
 910                 /*
 911                  * Check whether this memory bank would entirely overlap
 912                  * the vmalloc area.
 913                  */
 914                 if (__va(bank->start) >= vmalloc_min ||
 915                     __va(bank->start) < (void *)PAGE_OFFSET) {
 916                         printk(KERN_NOTICE "Ignoring RAM at %.8llx-%.8llx "
 917                                "(vmalloc region overlap).\n",
 918                                (unsigned long long)bank->start,
 919                                (unsigned long long)bank->start + bank->size - 1);
 920                         continue;
 921                 }
 922
 923                 /*
 924                  * Check whether this memory bank would partially overlap
 925                  * the vmalloc area.
 926                  */
 927                 if (__va(bank->start + bank->size) > vmalloc_min ||
 928                     __va(bank->start + bank->size) < __va(bank->start)) {
 929                         unsigned long newsize = vmalloc_min - __va(bank->start);
 930                         printk(KERN_NOTICE "Truncating RAM at %.8llx-%.8llx "
 931                                "to -%.8llx (vmalloc region overlap).\n",
 932                                (unsigned long long)bank->start,
 933                                (unsigned long long)bank->start + bank->size - 1,
 934                                (unsigned long long)bank->start + newsize - 1);
 935                         bank->size = newsize;
 936                 }
 937 #endif
 938                 if (!bank->highmem && bank->start + bank->size > arm_lowmem_limit)
 939                         arm_lowmem_limit = bank->start + bank->size;
 940
 941                 j++;
 942         }
 943 #ifdef CONFIG_HIGHMEM
 944         if (highmem) {
 945                 const char *reason = NULL;
 946
 947                 if (cache_is_vipt_aliasing()) {
 948                         /*
 949                          * Interactions between kmap and other mappings
 950                          * make highmem support with aliasing VIPT caches
 951                          * rather difficult.
 952                          */
 953                         reason = "with VIPT aliasing cache";
 954                 }
 955                 if (reason) {
 956                         printk(KERN_CRIT "HIGHMEM is not supported %s, ignoring high memory\n",
 957                                 reason);
 958                         while (j > 0 && meminfo.bank[j - 1].highmem)
 959                                 j--;
 960                 }
 961         }
 962 #endif
 963         meminfo.nr_banks = j;
 964         high_memory = __va(arm_lowmem_limit - 1) + 1;
 965         memblock_set_current_limit(arm_lowmem_limit);
 966 }
 967
 968 static inline void prepare_page_table(void)
 969 {
 970         unsigned long addr;
 971         phys_addr_t end;
 972
 973         /*
 974          * Clear out all the mappings below the kernel image.
 975          */
 976         for (addr = 0; addr < MODULES_VADDR; addr += PMD_SIZE)
 977                 pmd_clear(pmd_off_k(addr));
 978
 979 #ifdef CONFIG_XIP_KERNEL
 980         /* The XIP kernel is mapped in the module area -- skip over it */
 981         addr = ((unsigned long)_etext + PMD_SIZE - 1) & PMD_MASK;
 982 #endif
 983         for ( ; addr < PAGE_OFFSET; addr += PMD_SIZE)
 984                 pmd_clear(pmd_off_k(addr));
 985
 986         /*
 987          * Find the end of the first block of lowmem.
 988          */
 989         end = memblock.memory.regions[0].base + memblock.memory.regions[0].size;
 990         if (end >= arm_lowmem_limit)
 991                 end = arm_lowmem_limit;
 992
 993         /*
 994          * Clear out all the kernel space mappings, except for the first
 995          * memory bank, up to the vmalloc region.
 996          */
 997         for (addr = __phys_to_virt(end);
 998              addr < VMALLOC_START; addr += PMD_SIZE)
 999                 pmd_clear(pmd_off_k(addr));
1000 }
1001
1002 #ifdef CONFIG_ARM_LPAE
1003 /* the first page is reserved for pgd */
1004 #define SWAPPER_PG_DIR_SIZE     (PAGE_SIZE + \
1005                                  PTRS_PER_PGD * PTRS_PER_PMD * sizeof(pmd_t))
1006 #else
1007 #define SWAPPER_PG_DIR_SIZE     (PTRS_PER_PGD * sizeof(pgd_t))
1008 #endif
1009
1010 /*
1011  * Reserve the special regions of memory
1012  */
1013 void __init arm_mm_memblock_reserve(void)
1014 {
1015         /*
1016          * Reserve the page tables.  These are already in use,
1017          * and can only be in node 0.
1018          */
1019         memblock_reserve(__pa(swapper_pg_dir), SWAPPER_PG_DIR_SIZE);
1020
1021 #ifdef CONFIG_SA1111
1022         /*
1023          * Because of the SA1111 DMA bug, we want to preserve our
1024          * precious DMA-able memory...
1025          */
1026         memblock_reserve(PHYS_OFFSET, __pa(swapper_pg_dir) - PHYS_OFFSET);
1027 #endif
1028 }
1029
1030 /*
1031  * Set up the device mappings.  Since we clear out the page tables for all
1032  * mappings above VMALLOC_START, we will remove any debug device mappings.
1033  * This means you have to be careful how you debug this function, or any
1034  * called function.  This means you can't use any function or debugging
1035  * method which may touch any device, otherwise the kernel _will_ crash.
1036  */
1037 static void __init devicemaps_init(struct machine_desc *mdesc)
1038 {
1039         struct map_desc map;
1040         unsigned long addr;
1041
1042         /*
1043          * Allocate the vector page early.
1044          */
1045         vectors_page = early_alloc(PAGE_SIZE);
1046
1047         for (addr = VMALLOC_START; addr; addr += PMD_SIZE)
1048                 pmd_clear(pmd_off_k(addr));
1049
1050         /*
1051          * Map the kernel if it is XIP.
1052          * It is always first in the modulearea.
1053          */
1054 #ifdef CONFIG_XIP_KERNEL
1055         map.pfn = __phys_to_pfn(CONFIG_XIP_PHYS_ADDR & SECTION_MASK);
1056         map.virtual = MODULES_VADDR;
1057         map.length = ((unsigned long)_etext - map.virtual + ~SECTION_MASK) & SECTION_MASK;
1058         map.type = MT_ROM;
1059         create_mapping(&map);
1060 #endif
1061
1062         /*
1063          * Map the cache flushing regions.
1064          */
1065 #ifdef FLUSH_BASE
1066         map.pfn = __phys_to_pfn(FLUSH_BASE_PHYS);
1067         map.virtual = FLUSH_BASE;
1068         map.length = SZ_1M;
1069         map.type = MT_CACHECLEAN;
1070         create_mapping(&map);
1071 #endif
1072 #ifdef FLUSH_BASE_MINICACHE
1073         map.pfn = __phys_to_pfn(FLUSH_BASE_PHYS + SZ_1M);
1074         map.virtual = FLUSH_BASE_MINICACHE;
1075         map.length = SZ_1M;
1076         map.type = MT_MINICLEAN;
1077         create_mapping(&map);
1078 #endif
1079
1080         /*
1081          * Create a mapping for the machine vectors at the high-vectors
1082          * location (0xffff0000).  If we aren't using high-vectors, also
1083          * create a mapping at the low-vectors virtual address.
1084          */
1085         map.pfn = __phys_to_pfn(virt_to_phys(vectors_page));
1086         map.virtual = 0xffff0000;
1087         map.length = PAGE_SIZE;
1088         map.type = MT_HIGH_VECTORS;
1089         create_mapping(&map);
1090
1091         if (!vectors_high()) {
1092                 map.virtual = 0;
1093                 map.type = MT_LOW_VECTORS;
1094                 create_mapping(&map);
1095         }
1096
1097         /*
1098          * Ask the machine support to map in the statically mapped devices.
1099          */
1100         if (mdesc->map_io)
1101                 mdesc->map_io();
1102
1103         /*
1104          * Finally flush the caches and tlb to ensure that we're in a
1105          * consistent state wrt the writebuffer.  This also ensures that
1106          * any write-allocated cache lines in the vector page are written
1107          * back.  After this point, we can start to touch devices again.
1108          */
1109         local_flush_tlb_all();
1110         flush_cache_all();
1111 }
1112
1113 static void __init kmap_init(void)
1114 {
1115 #ifdef CONFIG_HIGHMEM
1116         pkmap_page_table = early_pte_alloc(pmd_off_k(PKMAP_BASE),
1117                 PKMAP_BASE, _PAGE_KERNEL_TABLE);
1118 #endif
1119 }
1120
1121 static void __init map_lowmem(void)
1122 {
1123         struct memblock_region *reg;
1124
1125         /* Map all the lowmem memory banks. */
1126         for_each_memblock(memory, reg) {
1127                 phys_addr_t start = reg->base;
1128                 phys_addr_t end = start + reg->size;
1129                 struct map_desc map;
1130
1131                 if (end > arm_lowmem_limit)
1132                         end = arm_lowmem_limit;
1133                 if (start >= end)
1134                         break;
1135
1136                 map.pfn = __phys_to_pfn(start);
1137                 map.virtual = __phys_to_virt(start);
1138                 map.length = end - start;
1139                 map.type = MT_MEMORY;
1140
1141                 create_mapping(&map);
1142         }
1143 }
1144
1145 /*
1146  * paging_init() sets up the page tables, initialises the zone memory
1147  * maps, and sets up the zero page, bad page and bad page tables.
1148  */
1149 void __init paging_init(struct machine_desc *mdesc)
1150 {
1151         void *zero_page;
1152
1153         memblock_set_current_limit(arm_lowmem_limit);
1154
1155         build_mem_type_table();
1156         prepare_page_table();
1157         map_lowmem();
1158         dma_contiguous_remap();
1159         devicemaps_init(mdesc);
1160         kmap_init();
1161
1162         top_pmd = pmd_off_k(0xffff0000);
1163
1164         /* allocate the zero page. */
1165         zero_page = early_alloc(PAGE_SIZE);
1166
1167         bootmem_init();
1168
1169         empty_zero_page = virt_to_page(zero_page);
1170         __flush_dcache_page(NULL, empty_zero_page);
1171 }