arch/arm/mm/init.c

   1 /*
   2  *  linux/arch/arm/mm/init.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/kernel.h>
  11 #include <linux/errno.h>
  12 #include <linux/swap.h>
  13 #include <linux/init.h>
  14 #include <linux/bootmem.h>
  15 #include <linux/mman.h>
  16 #include <linux/export.h>
  17 #include <linux/nodemask.h>
  18 #include <linux/initrd.h>
  19 #include <linux/of_fdt.h>
  20 #include <linux/highmem.h>
  21 #include <linux/gfp.h>
  22 #include <linux/memblock.h>
  23 #include <linux/dma-contiguous.h>
  24 #include <linux/sizes.h>
  25 #include <linux/stop_machine.h>
  26
  27 #include <asm/cp15.h>
  28 #include <asm/mach-types.h>
  29 #include <asm/memblock.h>
  30 #include <asm/prom.h>
  31 #include <asm/sections.h>
  32 #include <asm/setup.h>
  33 #include <asm/system_info.h>
  34 #include <asm/tlb.h>
  35 #include <asm/fixmap.h>
  36
  37 #include <asm/mach/arch.h>
  38 #include <asm/mach/map.h>
  39
  40 #include "mm.h"
  41
  42 #ifdef CONFIG_CPU_CP15_MMU
  43 unsigned long __init __clear_cr(unsigned long mask)
  44 {
  45         cr_alignment = cr_alignment & ~mask;
  46         return cr_alignment;
  47 }
  48 #endif
  49
  50 static phys_addr_t phys_initrd_start __initdata = 0;
  51 static unsigned long phys_initrd_size __initdata = 0;
  52
  53 static int __init early_initrd(char *p)
  54 {
  55         phys_addr_t start;
  56         unsigned long size;
  57         char *endp;
  58
  59         start = memparse(p, &endp);
  60         if (*endp == ',') {
  61                 size = memparse(endp + 1, NULL);
  62
  63                 phys_initrd_start = start;
  64                 phys_initrd_size = size;
  65         }
  66         return 0;
  67 }
  68 early_param("initrd", early_initrd);
  69
  70 static int __init parse_tag_initrd(const struct tag *tag)
  71 {
  72         pr_warn("ATAG_INITRD is deprecated; "
  73                 "please update your bootloader.\n");
  74         phys_initrd_start = __virt_to_phys(tag->u.initrd.start);
  75         phys_initrd_size = tag->u.initrd.size;
  76         return 0;
  77 }
  78
  79 __tagtable(ATAG_INITRD, parse_tag_initrd);
  80
  81 static int __init parse_tag_initrd2(const struct tag *tag)
  82 {
  83         phys_initrd_start = tag->u.initrd.start;
  84         phys_initrd_size = tag->u.initrd.size;
  85         return 0;
  86 }
  87
  88 __tagtable(ATAG_INITRD2, parse_tag_initrd2);
  89
  90 static void __init find_limits(unsigned long *min, unsigned long *max_low,
  91                                unsigned long *max_high)
  92 {
  93         *max_low = PFN_DOWN(memblock_get_current_limit());
  94         *min = PFN_UP(memblock_start_of_DRAM());
  95         *max_high = PFN_DOWN(memblock_end_of_DRAM());
  96 }
  97
  98 #ifdef CONFIG_ZONE_DMA
  99
 100 phys_addr_t arm_dma_zone_size __read_mostly;
 101 EXPORT_SYMBOL(arm_dma_zone_size);
 102
 103 /*
 104  * The DMA mask corresponding to the maximum bus address allocatable
 105  * using GFP_DMA.  The default here places no restriction on DMA
 106  * allocations.  This must be the smallest DMA mask in the system,
 107  * so a successful GFP_DMA allocation will always satisfy this.
 108  */
 109 phys_addr_t arm_dma_limit;
 110 unsigned long arm_dma_pfn_limit;
 111
 112 static void __init arm_adjust_dma_zone(unsigned long *size, unsigned long *hole,
 113         unsigned long dma_size)
 114 {
 115         if (size[0] <= dma_size)
 116                 return;
 117
 118         size[ZONE_NORMAL] = size[0] - dma_size;
 119         size[ZONE_DMA] = dma_size;
 120         hole[ZONE_NORMAL] = hole[0];
 121         hole[ZONE_DMA] = 0;
 122 }
 123 #endif
 124
 125 void __init setup_dma_zone(const struct machine_desc *mdesc)
 126 {
 127 #ifdef CONFIG_ZONE_DMA
 128         if (mdesc->dma_zone_size) {
 129                 arm_dma_zone_size = mdesc->dma_zone_size;
 130                 arm_dma_limit = PHYS_OFFSET + arm_dma_zone_size - 1;
 131         } else
 132                 arm_dma_limit = 0xffffffff;
 133         arm_dma_pfn_limit = arm_dma_limit >> PAGE_SHIFT;
 134 #endif
 135 }
 136
 137 static void __init zone_sizes_init(unsigned long min, unsigned long max_low,
 138         unsigned long max_high)
 139 {
 140         unsigned long zone_size[MAX_NR_ZONES], zhole_size[MAX_NR_ZONES];
 141         struct memblock_region *reg;
 142
 143         /*
 144          * initialise the zones.
 145          */
 146         memset(zone_size, 0, sizeof(zone_size));
 147
 148         /*
 149          * The memory size has already been determined.  If we need
 150          * to do anything fancy with the allocation of this memory
 151          * to the zones, now is the time to do it.
 152          */
 153         zone_size[0] = max_low - min;
 154 #ifdef CONFIG_HIGHMEM
 155         zone_size[ZONE_HIGHMEM] = max_high - max_low;
 156 #endif
 157
 158         /*
 159          * Calculate the size of the holes.
 160          *  holes = node_size - sum(bank_sizes)
 161          */
 162         memcpy(zhole_size, zone_size, sizeof(zhole_size));
 163         for_each_memblock(memory, reg) {
 164                 unsigned long start = memblock_region_memory_base_pfn(reg);
 165                 unsigned long end = memblock_region_memory_end_pfn(reg);
 166
 167                 if (start < max_low) {
 168                         unsigned long low_end = min(end, max_low);
 169                         zhole_size[0] -= low_end - start;
 170                 }
 171 #ifdef CONFIG_HIGHMEM
 172                 if (end > max_low) {
 173                         unsigned long high_start = max(start, max_low);
 174                         zhole_size[ZONE_HIGHMEM] -= end - high_start;
 175                 }
 176 #endif
 177         }
 178
 179 #ifdef CONFIG_ZONE_DMA
 180         /*
 181          * Adjust the sizes according to any special requirements for
 182          * this machine type.
 183          */
 184         if (arm_dma_zone_size)
 185                 arm_adjust_dma_zone(zone_size, zhole_size,
 186                         arm_dma_zone_size >> PAGE_SHIFT);
 187 #endif
 188
 189         free_area_init_node(0, zone_size, min, zhole_size);
 190 }
 191
 192 #ifdef CONFIG_HAVE_ARCH_PFN_VALID
 193 int pfn_valid(unsigned long pfn)
 194 {
 195         phys_addr_t addr = __pfn_to_phys(pfn);
 196
 197         if (__phys_to_pfn(addr) != pfn)
 198                 return 0;
 199
 200         return memblock_is_map_memory(__pfn_to_phys(pfn));
 201 }
 202 EXPORT_SYMBOL(pfn_valid);
 203 #endif
 204
 205 #ifndef CONFIG_SPARSEMEM
 206 static void __init arm_memory_present(void)
 207 {
 208 }
 209 #else
 210 static void __init arm_memory_present(void)
 211 {
 212         struct memblock_region *reg;
 213
 214         for_each_memblock(memory, reg)
 215                 memory_present(0, memblock_region_memory_base_pfn(reg),
 216                                memblock_region_memory_end_pfn(reg));
 217 }
 218 #endif
 219
 220 static bool arm_memblock_steal_permitted = true;
 221
 222 phys_addr_t __init arm_memblock_steal(phys_addr_t size, phys_addr_t align)
 223 {
 224         phys_addr_t phys;
 225
 226         BUG_ON(!arm_memblock_steal_permitted);
 227
 228         phys = memblock_alloc_base(size, align, MEMBLOCK_ALLOC_ANYWHERE);
 229         memblock_free(phys, size);
 230         memblock_remove(phys, size);
 231
 232         return phys;
 233 }
 234
 235 void __init arm_memblock_init(const struct machine_desc *mdesc)
 236 {
 237         /* Register the kernel text, kernel data and initrd with memblock. */
 238 #ifdef CONFIG_XIP_KERNEL
 239         memblock_reserve(__pa(_sdata), _end - _sdata);
 240 #else
 241         memblock_reserve(__pa(_stext), _end - _stext);
 242 #endif
 243 #ifdef CONFIG_BLK_DEV_INITRD
 244         /* FDT scan will populate initrd_start */
 245         if (initrd_start && !phys_initrd_size) {
 246                 phys_initrd_start = __virt_to_phys(initrd_start);
 247                 phys_initrd_size = initrd_end - initrd_start;
 248         }
 249         initrd_start = initrd_end = 0;
 250         if (phys_initrd_size &&
 251             !memblock_is_region_memory(phys_initrd_start, phys_initrd_size)) {
 252                 pr_err("INITRD: 0x%08llx+0x%08lx is not a memory region - disabling initrd\n",
 253                        (u64)phys_initrd_start, phys_initrd_size);
 254                 phys_initrd_start = phys_initrd_size = 0;
 255         }
 256         if (phys_initrd_size &&
 257             memblock_is_region_reserved(phys_initrd_start, phys_initrd_size)) {
 258                 pr_err("INITRD: 0x%08llx+0x%08lx overlaps in-use memory region - disabling initrd\n",
 259                        (u64)phys_initrd_start, phys_initrd_size);
 260                 phys_initrd_start = phys_initrd_size = 0;
 261         }
 262         if (phys_initrd_size) {
 263                 memblock_reserve(phys_initrd_start, phys_initrd_size);
 264
 265                 /* Now convert initrd to virtual addresses */
 266                 initrd_start = __phys_to_virt(phys_initrd_start);
 267                 initrd_end = initrd_start + phys_initrd_size;
 268         }
 269 #endif
 270
 271         arm_mm_memblock_reserve();
 272
 273         /* reserve any platform specific memblock areas */
 274         if (mdesc->reserve)
 275                 mdesc->reserve();
 276
 277         early_init_fdt_reserve_self();
 278         early_init_fdt_scan_reserved_mem();
 279
 280         /* reserve memory for DMA contiguous allocations */
 281         dma_contiguous_reserve(arm_dma_limit);
 282
 283         arm_memblock_steal_permitted = false;
 284         memblock_dump_all();
 285 }
 286
 287 void __init bootmem_init(void)
 288 {
 289         unsigned long min, max_low, max_high;
 290
 291         memblock_allow_resize();
 292         max_low = max_high = 0;
 293
 294         find_limits(&min, &max_low, &max_high);
 295
 296         early_memtest((phys_addr_t)min << PAGE_SHIFT,
 297                       (phys_addr_t)max_low << PAGE_SHIFT);
 298
 299         /*
 300          * Sparsemem tries to allocate bootmem in memory_present(),
 301          * so must be done after the fixed reservations
 302          */
 303         arm_memory_present();
 304
 305         /*
 306          * sparse_init() needs the bootmem allocator up and running.
 307          */
 308         sparse_init();
 309
 310         /*
 311          * Now free the memory - free_area_init_node needs
 312          * the sparse mem_map arrays initialized by sparse_init()
 313          * for memmap_init_zone(), otherwise all PFNs are invalid.
 314          */
 315         zone_sizes_init(min, max_low, max_high);
 316
 317         /*
 318          * This doesn't seem to be used by the Linux memory manager any
 319          * more, but is used by ll_rw_block.  If we can get rid of it, we
 320          * also get rid of some of the stuff above as well.
 321          */
 322         min_low_pfn = min;
 323         max_low_pfn = max_low;
 324         max_pfn = max_high;
 325 }
 326
 327 /*
 328  * Poison init memory with an undefined instruction (ARM) or a branch to an
 329  * undefined instruction (Thumb).
 330  */
 331 static inline void poison_init_mem(void *s, size_t count)
 332 {
 333         u32 *p = (u32 *)s;
 334         for (; count != 0; count -= 4)
 335                 *p++ = 0xe7fddef0;
 336 }
 337
 338 static inline void
 339 free_memmap(unsigned long start_pfn, unsigned long end_pfn)
 340 {
 341         struct page *start_pg, *end_pg;
 342         phys_addr_t pg, pgend;
 343
 344         /*
 345          * Convert start_pfn/end_pfn to a struct page pointer.
 346          */
 347         start_pg = pfn_to_page(start_pfn - 1) + 1;
 348         end_pg = pfn_to_page(end_pfn - 1) + 1;
 349
 350         /*
 351          * Convert to physical addresses, and
 352          * round start upwards and end downwards.
 353          */
 354         pg = PAGE_ALIGN(__pa(start_pg));
 355         pgend = __pa(end_pg) & PAGE_MASK;
 356
 357         /*
 358          * If there are free pages between these,
 359          * free the section of the memmap array.
 360          */
 361         if (pg < pgend)
 362                 memblock_free_early(pg, pgend - pg);
 363 }
 364
 365 /*
 366  * The mem_map array can get very big.  Free the unused area of the memory map.
 367  */
 368 static void __init free_unused_memmap(void)
 369 {
 370         unsigned long start, prev_end = 0;
 371         struct memblock_region *reg;
 372
 373         /*
 374          * This relies on each bank being in address order.
 375          * The banks are sorted previously in bootmem_init().
 376          */
 377         for_each_memblock(memory, reg) {
 378                 start = memblock_region_memory_base_pfn(reg);
 379
 380 #ifdef CONFIG_SPARSEMEM
 381                 /*
 382                  * Take care not to free memmap entries that don't exist
 383                  * due to SPARSEMEM sections which aren't present.
 384                  */
 385                 start = min(start,
 386                                  ALIGN(prev_end, PAGES_PER_SECTION));
 387 #else
 388                 /*
 389                  * Align down here since the VM subsystem insists that the
 390                  * memmap entries are valid from the bank start aligned to
 391                  * MAX_ORDER_NR_PAGES.
 392                  */
 393                 start = round_down(start, MAX_ORDER_NR_PAGES);
 394 #endif
 395                 /*
 396                  * If we had a previous bank, and there is a space
 397                  * between the current bank and the previous, free it.
 398                  */
 399                 if (prev_end && prev_end < start)
 400                         free_memmap(prev_end, start);
 401
 402                 /*
 403                  * Align up here since the VM subsystem insists that the
 404                  * memmap entries are valid from the bank end aligned to
 405                  * MAX_ORDER_NR_PAGES.
 406                  */
 407                 prev_end = ALIGN(memblock_region_memory_end_pfn(reg),
 408                                  MAX_ORDER_NR_PAGES);
 409         }
 410
 411 #ifdef CONFIG_SPARSEMEM
 412         if (!IS_ALIGNED(prev_end, PAGES_PER_SECTION))
 413                 free_memmap(prev_end,
 414                             ALIGN(prev_end, PAGES_PER_SECTION));
 415 #endif
 416 }
 417
 418 #ifdef CONFIG_HIGHMEM
 419 static inline void free_area_high(unsigned long pfn, unsigned long end)
 420 {
 421         for (; pfn < end; pfn++)
 422                 free_highmem_page(pfn_to_page(pfn));
 423 }
 424 #endif
 425
 426 static void __init free_highpages(void)
 427 {
 428 #ifdef CONFIG_HIGHMEM
 429         unsigned long max_low = max_low_pfn;
 430         struct memblock_region *mem, *res;
 431
 432         /* set highmem page free */
 433         for_each_memblock(memory, mem) {
 434                 unsigned long start = memblock_region_memory_base_pfn(mem);
 435                 unsigned long end = memblock_region_memory_end_pfn(mem);
 436
 437                 /* Ignore complete lowmem entries */
 438                 if (end <= max_low)
 439                         continue;
 440
 441                 if (memblock_is_nomap(mem))
 442                         continue;
 443
 444                 /* Truncate partial highmem entries */
 445                 if (start < max_low)
 446                         start = max_low;
 447
 448                 /* Find and exclude any reserved regions */
 449                 for_each_memblock(reserved, res) {
 450                         unsigned long res_start, res_end;
 451
 452                         res_start = memblock_region_reserved_base_pfn(res);
 453                         res_end = memblock_region_reserved_end_pfn(res);
 454
 455                         if (res_end < start)
 456                                 continue;
 457                         if (res_start < start)
 458                                 res_start = start;
 459                         if (res_start > end)
 460                                 res_start = end;
 461                         if (res_end > end)
 462                                 res_end = end;
 463                         if (res_start != start)
 464                                 free_area_high(start, res_start);
 465                         start = res_end;
 466                         if (start == end)
 467                                 break;
 468                 }
 469
 470                 /* And now free anything which remains */
 471                 if (start < end)
 472                         free_area_high(start, end);
 473         }
 474 #endif
 475 }
 476
 477 /*
 478  * mem_init() marks the free areas in the mem_map and tells us how much
 479  * memory is free.  This is done after various parts of the system have
 480  * claimed their memory after the kernel image.
 481  */
 482 void __init mem_init(void)
 483 {
 484 #ifdef CONFIG_HAVE_TCM
 485         /* These pointers are filled in on TCM detection */
 486         extern u32 dtcm_end;
 487         extern u32 itcm_end;
 488 #endif
 489
 490         set_max_mapnr(pfn_to_page(max_pfn) - mem_map);
 491
 492         /* this will put all unused low memory onto the freelists */
 493         free_unused_memmap();
 494         free_all_bootmem();
 495
 496 #ifdef CONFIG_SA1111
 497         /* now that our DMA memory is actually so designated, we can free it */
 498         free_reserved_area(__va(PHYS_OFFSET), swapper_pg_dir, -1, NULL);
 499 #endif
 500
 501         free_highpages();
 502
 503         mem_init_print_info(NULL);
 504
 505 #define MLK(b, t) b, t, ((t) - (b)) >> 10
 506 #define MLM(b, t) b, t, ((t) - (b)) >> 20
 507 #define MLK_ROUNDUP(b, t) b, t, DIV_ROUND_UP(((t) - (b)), SZ_1K)
 508
 509         pr_notice("Virtual kernel memory layout:\n"
 510                         "    vector  : 0x%08lx - 0x%08lx   (%4ld kB)\n"
 511 #ifdef CONFIG_HAVE_TCM
 512                         "    DTCM    : 0x%08lx - 0x%08lx   (%4ld kB)\n"
 513                         "    ITCM    : 0x%08lx - 0x%08lx   (%4ld kB)\n"
 514 #endif
 515                         "    fixmap  : 0x%08lx - 0x%08lx   (%4ld kB)\n"
 516                         "    vmalloc : 0x%08lx - 0x%08lx   (%4ld MB)\n"
 517                         "    lowmem  : 0x%08lx - 0x%08lx   (%4ld MB)\n"
 518 #ifdef CONFIG_HIGHMEM
 519                         "    pkmap   : 0x%08lx - 0x%08lx   (%4ld MB)\n"
 520 #endif
 521 #ifdef CONFIG_MODULES
 522                         "    modules : 0x%08lx - 0x%08lx   (%4ld MB)\n"
 523 #endif
 524                         "      .text : 0x%p" " - 0x%p" "   (%4td kB)\n"
 525                         "      .init : 0x%p" " - 0x%p" "   (%4td kB)\n"
 526                         "      .data : 0x%p" " - 0x%p" "   (%4td kB)\n"
 527                         "       .bss : 0x%p" " - 0x%p" "   (%4td kB)\n",
 528
 529                         MLK(UL(CONFIG_VECTORS_BASE), UL(CONFIG_VECTORS_BASE) +
 530                                 (PAGE_SIZE)),
 531 #ifdef CONFIG_HAVE_TCM
 532                         MLK(DTCM_OFFSET, (unsigned long) dtcm_end),
 533                         MLK(ITCM_OFFSET, (unsigned long) itcm_end),
 534 #endif
 535                         MLK(FIXADDR_START, FIXADDR_END),
 536                         MLM(VMALLOC_START, VMALLOC_END),
 537                         MLM(PAGE_OFFSET, (unsigned long)high_memory),
 538 #ifdef CONFIG_HIGHMEM
 539                         MLM(PKMAP_BASE, (PKMAP_BASE) + (LAST_PKMAP) *
 540                                 (PAGE_SIZE)),
 541 #endif
 542 #ifdef CONFIG_MODULES
 543                         MLM(MODULES_VADDR, MODULES_END),
 544 #endif
 545
 546                         MLK_ROUNDUP(_text, _etext),
 547                         MLK_ROUNDUP(__init_begin, __init_end),
 548                         MLK_ROUNDUP(_sdata, _edata),
 549                         MLK_ROUNDUP(__bss_start, __bss_stop));
 550
 551 #undef MLK
 552 #undef MLM
 553 #undef MLK_ROUNDUP
 554
 555         /*
 556          * Check boundaries twice: Some fundamental inconsistencies can
 557          * be detected at build time already.
 558          */
 559 #ifdef CONFIG_MMU
 560         BUILD_BUG_ON(TASK_SIZE                          > MODULES_VADDR);
 561         BUG_ON(TASK_SIZE                                > MODULES_VADDR);
 562 #endif
 563
 564 #ifdef CONFIG_HIGHMEM
 565         BUILD_BUG_ON(PKMAP_BASE + LAST_PKMAP * PAGE_SIZE > PAGE_OFFSET);
 566         BUG_ON(PKMAP_BASE + LAST_PKMAP * PAGE_SIZE      > PAGE_OFFSET);
 567 #endif
 568
 569         if (PAGE_SIZE >= 16384 && get_num_physpages() <= 128) {
 570                 extern int sysctl_overcommit_memory;
 571                 /*
 572                  * On a machine this small we won't get
 573                  * anywhere without overcommit, so turn
 574                  * it on by default.
 575                  */
 576                 sysctl_overcommit_memory = OVERCOMMIT_ALWAYS;
 577         }
 578 }
 579
 580 #ifdef CONFIG_DEBUG_RODATA
 581 struct section_perm {
 582         const char *name;
 583         unsigned long start;
 584         unsigned long end;
 585         pmdval_t mask;
 586         pmdval_t prot;
 587         pmdval_t clear;
 588 };
 589
 590 /* First section-aligned location at or after __start_rodata. */
 591 extern char __start_rodata_section_aligned[];
 592
 593 static struct section_perm nx_perms[] = {
 594         /* Make pages tables, etc before _stext RW (set NX). */
 595         {
 596                 .name   = "pre-text NX",
 597                 .start  = PAGE_OFFSET,
 598                 .end    = (unsigned long)_stext,
 599                 .mask   = ~PMD_SECT_XN,
 600                 .prot   = PMD_SECT_XN,
 601         },
 602         /* Make init RW (set NX). */
 603         {
 604                 .name   = "init NX",
 605                 .start  = (unsigned long)__init_begin,
 606                 .end    = (unsigned long)_sdata,
 607                 .mask   = ~PMD_SECT_XN,
 608                 .prot   = PMD_SECT_XN,
 609         },
 610         /* Make rodata NX (set RO in ro_perms below). */
 611         {
 612                 .name   = "rodata NX",
 613                 .start  = (unsigned long)__start_rodata_section_aligned,
 614                 .end    = (unsigned long)__init_begin,
 615                 .mask   = ~PMD_SECT_XN,
 616                 .prot   = PMD_SECT_XN,
 617         },
 618 };
 619
 620 static struct section_perm ro_perms[] = {
 621         /* Make kernel code and rodata RX (set RO). */
 622         {
 623                 .name   = "text/rodata RO",
 624                 .start  = (unsigned long)_stext,
 625                 .end    = (unsigned long)__init_begin,
 626 #ifdef CONFIG_ARM_LPAE
 627                 .mask   = ~(L_PMD_SECT_RDONLY | PMD_SECT_AP2),
 628                 .prot   = L_PMD_SECT_RDONLY | PMD_SECT_AP2,
 629 #else
 630                 .mask   = ~(PMD_SECT_APX | PMD_SECT_AP_WRITE),
 631                 .prot   = PMD_SECT_APX | PMD_SECT_AP_WRITE,
 632                 .clear  = PMD_SECT_AP_WRITE,
 633 #endif
 634         },
 635 };
 636
 637 /*
 638  * Updates section permissions only for the current mm (sections are
 639  * copied into each mm). During startup, this is the init_mm. Is only
 640  * safe to be called with preemption disabled, as under stop_machine().
 641  */
 642 static inline void section_update(unsigned long addr, pmdval_t mask,
 643                                   pmdval_t prot, struct mm_struct *mm)
 644 {
 645         pmd_t *pmd;
 646
 647         pmd = pmd_offset(pud_offset(pgd_offset(mm, addr), addr), addr);
 648
 649 #ifdef CONFIG_ARM_LPAE
 650         pmd[0] = __pmd((pmd_val(pmd[0]) & mask) | prot);
 651 #else
 652         if (addr & SECTION_SIZE)
 653                 pmd[1] = __pmd((pmd_val(pmd[1]) & mask) | prot);
 654         else
 655                 pmd[0] = __pmd((pmd_val(pmd[0]) & mask) | prot);
 656 #endif
 657         flush_pmd_entry(pmd);
 658         local_flush_tlb_kernel_range(addr, addr + SECTION_SIZE);
 659 }
 660
 661 /* Make sure extended page tables are in use. */
 662 static inline bool arch_has_strict_perms(void)
 663 {
 664         if (cpu_architecture() < CPU_ARCH_ARMv6)
 665                 return false;
 666
 667         return !!(get_cr() & CR_XP);
 668 }
 669
 670 void set_section_perms(struct section_perm *perms, int n, bool set,
 671                         struct mm_struct *mm)
 672 {
 673         size_t i;
 674         unsigned long addr;
 675
 676         if (!arch_has_strict_perms())
 677                 return;
 678
 679         for (i = 0; i < n; i++) {
 680                 if (!IS_ALIGNED(perms[i].start, SECTION_SIZE) ||
 681                     !IS_ALIGNED(perms[i].end, SECTION_SIZE)) {
 682                         pr_err("BUG: %s section %lx-%lx not aligned to %lx\n",
 683                                 perms[i].name, perms[i].start, perms[i].end,
 684                                 SECTION_SIZE);
 685                         continue;
 686                 }
 687
 688                 for (addr = perms[i].start;
 689                      addr < perms[i].end;
 690                      addr += SECTION_SIZE)
 691                         section_update(addr, perms[i].mask,
 692                                 set ? perms[i].prot : perms[i].clear, mm);
 693         }
 694
 695 }
 696
 697 static void update_sections_early(struct section_perm perms[], int n)
 698 {
 699         struct task_struct *t, *s;
 700
 701         read_lock(&tasklist_lock);
 702         for_each_process(t) {
 703                 if (t->flags & PF_KTHREAD)
 704                         continue;
 705                 for_each_thread(t, s)
 706                         if (s->mm)
 707                                 set_section_perms(perms, n, true, s->mm);
 708         }
 709         read_unlock(&tasklist_lock);
 710         set_section_perms(perms, n, true, current->active_mm);
 711         set_section_perms(perms, n, true, &init_mm);
 712 }
 713
 714 int __fix_kernmem_perms(void *unused)
 715 {
 716         update_sections_early(nx_perms, ARRAY_SIZE(nx_perms));
 717         return 0;
 718 }
 719
 720 void fix_kernmem_perms(void)
 721 {
 722         stop_machine(__fix_kernmem_perms, NULL, NULL);
 723 }
 724
 725 int __mark_rodata_ro(void *unused)
 726 {
 727         update_sections_early(ro_perms, ARRAY_SIZE(ro_perms));
 728         return 0;
 729 }
 730
 731 static int kernel_set_to_readonly __read_mostly;
 732
 733 void mark_rodata_ro(void)
 734 {
 735         kernel_set_to_readonly = 1;
 736         stop_machine(__mark_rodata_ro, NULL, NULL);
 737 }
 738
 739 void set_kernel_text_rw(void)
 740 {
 741         if (!kernel_set_to_readonly)
 742                 return;
 743
 744         set_section_perms(ro_perms, ARRAY_SIZE(ro_perms), false,
 745                                 current->active_mm);
 746 }
 747
 748 void set_kernel_text_ro(void)
 749 {
 750         if (!kernel_set_to_readonly)
 751                 return;
 752
 753         set_section_perms(ro_perms, ARRAY_SIZE(ro_perms), true,
 754                                 current->active_mm);
 755 }
 756
 757 #else
 758 static inline void fix_kernmem_perms(void) { }
 759 #endif /* CONFIG_DEBUG_RODATA */
 760
 761 void free_tcmmem(void)
 762 {
 763 #ifdef CONFIG_HAVE_TCM
 764         extern char __tcm_start, __tcm_end;
 765
 766         poison_init_mem(&__tcm_start, &__tcm_end - &__tcm_start);
 767         free_reserved_area(&__tcm_start, &__tcm_end, -1, "TCM link");
 768 #endif
 769 }
 770
 771 void free_initmem(void)
 772 {
 773         fix_kernmem_perms();
 774         free_tcmmem();
 775
 776         poison_init_mem(__init_begin, __init_end - __init_begin);
 777         if (!machine_is_integrator() && !machine_is_cintegrator())
 778                 free_initmem_default(-1);
 779 }
 780
 781 #ifdef CONFIG_BLK_DEV_INITRD
 782
 783 static int keep_initrd;
 784
 785 void free_initrd_mem(unsigned long start, unsigned long end)
 786 {
 787         if (!keep_initrd) {
 788                 if (start == initrd_start)
 789                         start = round_down(start, PAGE_SIZE);
 790                 if (end == initrd_end)
 791                         end = round_up(end, PAGE_SIZE);
 792
 793                 poison_init_mem((void *)start, PAGE_ALIGN(end) - start);
 794                 free_reserved_area((void *)start, (void *)end, -1, "initrd");
 795         }
 796 }
 797
 798 static int __init keepinitrd_setup(char *__unused)
 799 {
 800         keep_initrd = 1;
 801         return 1;
 802 }
 803
 804 __setup("keepinitrd", keepinitrd_setup);
 805 #endif