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/sched/signal.h>
  17 #include <linux/sched/task.h>
  18 #include <linux/export.h>
  19 #include <linux/nodemask.h>
  20 #include <linux/initrd.h>
  21 #include <linux/of_fdt.h>
  22 #include <linux/highmem.h>
  23 #include <linux/gfp.h>
  24 #include <linux/memblock.h>
  25 #include <linux/dma-contiguous.h>
  26 #include <linux/sizes.h>
  27 #include <linux/stop_machine.h>
  28
  29 #include <asm/cp15.h>
  30 #include <asm/mach-types.h>
  31 #include <asm/memblock.h>
  32 #include <asm/memory.h>
  33 #include <asm/prom.h>
  34 #include <asm/sections.h>
  35 #include <asm/setup.h>
  36 #include <asm/system_info.h>
  37 #include <asm/tlb.h>
  38 #include <asm/fixmap.h>
  39
  40 #include <asm/mach/arch.h>
  41 #include <asm/mach/map.h>
  42
  43 #include "mm.h"
  44
  45 #ifdef CONFIG_CPU_CP15_MMU
  46 unsigned long __init __clear_cr(unsigned long mask)
  47 {
  48         cr_alignment = cr_alignment & ~mask;
  49         return cr_alignment;
  50 }
  51 #endif
  52
  53 static phys_addr_t phys_initrd_start __initdata = 0;
  54 static unsigned long phys_initrd_size __initdata = 0;
  55
  56 static int __init early_initrd(char *p)
  57 {
  58         phys_addr_t start;
  59         unsigned long size;
  60         char *endp;
  61
  62         start = memparse(p, &endp);
  63         if (*endp == ',') {
  64                 size = memparse(endp + 1, NULL);
  65
  66                 phys_initrd_start = start;
  67                 phys_initrd_size = size;
  68         }
  69         return 0;
  70 }
  71 early_param("initrd", early_initrd);
  72
  73 static int __init parse_tag_initrd(const struct tag *tag)
  74 {
  75         pr_warn("ATAG_INITRD is deprecated; "
  76                 "please update your bootloader.\n");
  77         phys_initrd_start = __virt_to_phys(tag->u.initrd.start);
  78         phys_initrd_size = tag->u.initrd.size;
  79         return 0;
  80 }
  81
  82 __tagtable(ATAG_INITRD, parse_tag_initrd);
  83
  84 static int __init parse_tag_initrd2(const struct tag *tag)
  85 {
  86         phys_initrd_start = tag->u.initrd.start;
  87         phys_initrd_size = tag->u.initrd.size;
  88         return 0;
  89 }
  90
  91 __tagtable(ATAG_INITRD2, parse_tag_initrd2);
  92
  93 static void __init find_limits(unsigned long *min, unsigned long *max_low,
  94                                unsigned long *max_high)
  95 {
  96         *max_low = PFN_DOWN(memblock_get_current_limit());
  97         *min = PFN_UP(memblock_start_of_DRAM());
  98         *max_high = PFN_DOWN(memblock_end_of_DRAM());
  99 }
 100
 101 #ifdef CONFIG_ZONE_DMA
 102
 103 phys_addr_t arm_dma_zone_size __read_mostly;
 104 EXPORT_SYMBOL(arm_dma_zone_size);
 105
 106 /*
 107  * The DMA mask corresponding to the maximum bus address allocatable
 108  * using GFP_DMA.  The default here places no restriction on DMA
 109  * allocations.  This must be the smallest DMA mask in the system,
 110  * so a successful GFP_DMA allocation will always satisfy this.
 111  */
 112 phys_addr_t arm_dma_limit;
 113 unsigned long arm_dma_pfn_limit;
 114
 115 static void __init arm_adjust_dma_zone(unsigned long *size, unsigned long *hole,
 116         unsigned long dma_size)
 117 {
 118         if (size[0] <= dma_size)
 119                 return;
 120
 121         size[ZONE_NORMAL] = size[0] - dma_size;
 122         size[ZONE_DMA] = dma_size;
 123         hole[ZONE_NORMAL] = hole[0];
 124         hole[ZONE_DMA] = 0;
 125 }
 126 #endif
 127
 128 void __init setup_dma_zone(const struct machine_desc *mdesc)
 129 {
 130 #ifdef CONFIG_ZONE_DMA
 131         if (mdesc->dma_zone_size) {
 132                 arm_dma_zone_size = mdesc->dma_zone_size;
 133                 arm_dma_limit = PHYS_OFFSET + arm_dma_zone_size - 1;
 134         } else
 135                 arm_dma_limit = 0xffffffff;
 136         arm_dma_pfn_limit = arm_dma_limit >> PAGE_SHIFT;
 137 #endif
 138 }
 139
 140 static void __init zone_sizes_init(unsigned long min, unsigned long max_low,
 141         unsigned long max_high)
 142 {
 143         unsigned long zone_size[MAX_NR_ZONES], zhole_size[MAX_NR_ZONES];
 144         struct memblock_region *reg;
 145
 146         /*
 147          * initialise the zones.
 148          */
 149         memset(zone_size, 0, sizeof(zone_size));
 150
 151         /*
 152          * The memory size has already been determined.  If we need
 153          * to do anything fancy with the allocation of this memory
 154          * to the zones, now is the time to do it.
 155          */
 156         zone_size[0] = max_low - min;
 157 #ifdef CONFIG_HIGHMEM
 158         zone_size[ZONE_HIGHMEM] = max_high - max_low;
 159 #endif
 160
 161         /*
 162          * Calculate the size of the holes.
 163          *  holes = node_size - sum(bank_sizes)
 164          */
 165         memcpy(zhole_size, zone_size, sizeof(zhole_size));
 166         for_each_memblock(memory, reg) {
 167                 unsigned long start = memblock_region_memory_base_pfn(reg);
 168                 unsigned long end = memblock_region_memory_end_pfn(reg);
 169
 170                 if (start < max_low) {
 171                         unsigned long low_end = min(end, max_low);
 172                         zhole_size[0] -= low_end - start;
 173                 }
 174 #ifdef CONFIG_HIGHMEM
 175                 if (end > max_low) {
 176                         unsigned long high_start = max(start, max_low);
 177                         zhole_size[ZONE_HIGHMEM] -= end - high_start;
 178                 }
 179 #endif
 180         }
 181
 182 #ifdef CONFIG_ZONE_DMA
 183         /*
 184          * Adjust the sizes according to any special requirements for
 185          * this machine type.
 186          */
 187         if (arm_dma_zone_size)
 188                 arm_adjust_dma_zone(zone_size, zhole_size,
 189                         arm_dma_zone_size >> PAGE_SHIFT);
 190 #endif
 191
 192         free_area_init_node(0, zone_size, min, zhole_size);
 193 }
 194
 195 #ifdef CONFIG_HAVE_ARCH_PFN_VALID
 196 int pfn_valid(unsigned long pfn)
 197 {
 198         phys_addr_t addr = __pfn_to_phys(pfn);
 199
 200         if (__phys_to_pfn(addr) != pfn)
 201                 return 0;
 202
 203         return memblock_is_map_memory(__pfn_to_phys(pfn));
 204 }
 205 EXPORT_SYMBOL(pfn_valid);
 206 #endif
 207
 208 #ifndef CONFIG_SPARSEMEM
 209 static void __init arm_memory_present(void)
 210 {
 211 }
 212 #else
 213 static void __init arm_memory_present(void)
 214 {
 215         struct memblock_region *reg;
 216
 217         for_each_memblock(memory, reg)
 218                 memory_present(0, memblock_region_memory_base_pfn(reg),
 219                                memblock_region_memory_end_pfn(reg));
 220 }
 221 #endif
 222
 223 static bool arm_memblock_steal_permitted = true;
 224
 225 phys_addr_t __init arm_memblock_steal(phys_addr_t size, phys_addr_t align)
 226 {
 227         phys_addr_t phys;
 228
 229         BUG_ON(!arm_memblock_steal_permitted);
 230
 231         phys = memblock_alloc_base(size, align, MEMBLOCK_ALLOC_ANYWHERE);
 232         memblock_free(phys, size);
 233         memblock_remove(phys, size);
 234
 235         return phys;
 236 }
 237
 238 static void __init arm_initrd_init(void)
 239 {
 240 #ifdef CONFIG_BLK_DEV_INITRD
 241         phys_addr_t start;
 242         unsigned long size;
 243
 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
 250         initrd_start = initrd_end = 0;
 251
 252         if (!phys_initrd_size)
 253                 return;
 254
 255         /*
 256          * Round the memory region to page boundaries as per free_initrd_mem()
 257          * This allows us to detect whether the pages overlapping the initrd
 258          * are in use, but more importantly, reserves the entire set of pages
 259          * as we don't want these pages allocated for other purposes.
 260          */
 261         start = round_down(phys_initrd_start, PAGE_SIZE);
 262         size = phys_initrd_size + (phys_initrd_start - start);
 263         size = round_up(size, PAGE_SIZE);
 264
 265         if (!memblock_is_region_memory(start, size)) {
 266                 pr_err("INITRD: 0x%08llx+0x%08lx is not a memory region - disabling initrd\n",
 267                        (u64)start, size);
 268                 return;
 269         }
 270
 271         if (memblock_is_region_reserved(start, size)) {
 272                 pr_err("INITRD: 0x%08llx+0x%08lx overlaps in-use memory region - disabling initrd\n",
 273                        (u64)start, size);
 274                 return;
 275         }
 276
 277         memblock_reserve(start, size);
 278
 279         /* Now convert initrd to virtual addresses */
 280         initrd_start = __phys_to_virt(phys_initrd_start);
 281         initrd_end = initrd_start + phys_initrd_size;
 282 #endif
 283 }
 284
 285 void __init arm_memblock_init(const struct machine_desc *mdesc)
 286 {
 287         /* Register the kernel text, kernel data and initrd with memblock. */
 288         memblock_reserve(__pa(KERNEL_START), KERNEL_END - KERNEL_START);
 289
 290         arm_initrd_init();
 291
 292         arm_mm_memblock_reserve();
 293
 294         /* reserve any platform specific memblock areas */
 295         if (mdesc->reserve)
 296                 mdesc->reserve();
 297
 298         early_init_fdt_reserve_self();
 299         early_init_fdt_scan_reserved_mem();
 300
 301         /* reserve memory for DMA contiguous allocations */
 302         dma_contiguous_reserve(arm_dma_limit);
 303
 304         arm_memblock_steal_permitted = false;
 305         memblock_dump_all();
 306 }
 307
 308 void __init bootmem_init(void)
 309 {
 310         unsigned long min, max_low, max_high;
 311
 312         memblock_allow_resize();
 313         max_low = max_high = 0;
 314
 315         find_limits(&min, &max_low, &max_high);
 316
 317         early_memtest((phys_addr_t)min << PAGE_SHIFT,
 318                       (phys_addr_t)max_low << PAGE_SHIFT);
 319
 320         /*
 321          * Sparsemem tries to allocate bootmem in memory_present(),
 322          * so must be done after the fixed reservations
 323          */
 324         arm_memory_present();
 325
 326         /*
 327          * sparse_init() needs the bootmem allocator up and running.
 328          */
 329         sparse_init();
 330
 331         /*
 332          * Now free the memory - free_area_init_node needs
 333          * the sparse mem_map arrays initialized by sparse_init()
 334          * for memmap_init_zone(), otherwise all PFNs are invalid.
 335          */
 336         zone_sizes_init(min, max_low, max_high);
 337
 338         /*
 339          * This doesn't seem to be used by the Linux memory manager any
 340          * more, but is used by ll_rw_block.  If we can get rid of it, we
 341          * also get rid of some of the stuff above as well.
 342          */
 343         min_low_pfn = min;
 344         max_low_pfn = max_low;
 345         max_pfn = max_high;
 346 }
 347
 348 /*
 349  * Poison init memory with an undefined instruction (ARM) or a branch to an
 350  * undefined instruction (Thumb).
 351  */
 352 static inline void poison_init_mem(void *s, size_t count)
 353 {
 354         u32 *p = (u32 *)s;
 355         for (; count != 0; count -= 4)
 356                 *p++ = 0xe7fddef0;
 357 }
 358
 359 static inline void __init
 360 free_memmap(unsigned long start_pfn, unsigned long end_pfn)
 361 {
 362         struct page *start_pg, *end_pg;
 363         phys_addr_t pg, pgend;
 364
 365         /*
 366          * Convert start_pfn/end_pfn to a struct page pointer.
 367          */
 368         start_pg = pfn_to_page(start_pfn - 1) + 1;
 369         end_pg = pfn_to_page(end_pfn - 1) + 1;
 370
 371         /*
 372          * Convert to physical addresses, and
 373          * round start upwards and end downwards.
 374          */
 375         pg = PAGE_ALIGN(__pa(start_pg));
 376         pgend = __pa(end_pg) & PAGE_MASK;
 377
 378         /*
 379          * If there are free pages between these,
 380          * free the section of the memmap array.
 381          */
 382         if (pg < pgend)
 383                 memblock_free_early(pg, pgend - pg);
 384 }
 385
 386 /*
 387  * The mem_map array can get very big.  Free the unused area of the memory map.
 388  */
 389 static void __init free_unused_memmap(void)
 390 {
 391         unsigned long start, prev_end = 0;
 392         struct memblock_region *reg;
 393
 394         /*
 395          * This relies on each bank being in address order.
 396          * The banks are sorted previously in bootmem_init().
 397          */
 398         for_each_memblock(memory, reg) {
 399                 start = memblock_region_memory_base_pfn(reg);
 400
 401 #ifdef CONFIG_SPARSEMEM
 402                 /*
 403                  * Take care not to free memmap entries that don't exist
 404                  * due to SPARSEMEM sections which aren't present.
 405                  */
 406                 start = min(start,
 407                                  ALIGN(prev_end, PAGES_PER_SECTION));
 408 #else
 409                 /*
 410                  * Align down here since the VM subsystem insists that the
 411                  * memmap entries are valid from the bank start aligned to
 412                  * MAX_ORDER_NR_PAGES.
 413                  */
 414                 start = round_down(start, MAX_ORDER_NR_PAGES);
 415 #endif
 416                 /*
 417                  * If we had a previous bank, and there is a space
 418                  * between the current bank and the previous, free it.
 419                  */
 420                 if (prev_end && prev_end < start)
 421                         free_memmap(prev_end, start);
 422
 423                 /*
 424                  * Align up here since the VM subsystem insists that the
 425                  * memmap entries are valid from the bank end aligned to
 426                  * MAX_ORDER_NR_PAGES.
 427                  */
 428                 prev_end = ALIGN(memblock_region_memory_end_pfn(reg),
 429                                  MAX_ORDER_NR_PAGES);
 430         }
 431
 432 #ifdef CONFIG_SPARSEMEM
 433         if (!IS_ALIGNED(prev_end, PAGES_PER_SECTION))
 434                 free_memmap(prev_end,
 435                             ALIGN(prev_end, PAGES_PER_SECTION));
 436 #endif
 437 }
 438
 439 #ifdef CONFIG_HIGHMEM
 440 static inline void free_area_high(unsigned long pfn, unsigned long end)
 441 {
 442         for (; pfn < end; pfn++)
 443                 free_highmem_page(pfn_to_page(pfn));
 444 }
 445 #endif
 446
 447 static void __init free_highpages(void)
 448 {
 449 #ifdef CONFIG_HIGHMEM
 450         unsigned long max_low = max_low_pfn;
 451         struct memblock_region *mem, *res;
 452
 453         /* set highmem page free */
 454         for_each_memblock(memory, mem) {
 455                 unsigned long start = memblock_region_memory_base_pfn(mem);
 456                 unsigned long end = memblock_region_memory_end_pfn(mem);
 457
 458                 /* Ignore complete lowmem entries */
 459                 if (end <= max_low)
 460                         continue;
 461
 462                 if (memblock_is_nomap(mem))
 463                         continue;
 464
 465                 /* Truncate partial highmem entries */
 466                 if (start < max_low)
 467                         start = max_low;
 468
 469                 /* Find and exclude any reserved regions */
 470                 for_each_memblock(reserved, res) {
 471                         unsigned long res_start, res_end;
 472
 473                         res_start = memblock_region_reserved_base_pfn(res);
 474                         res_end = memblock_region_reserved_end_pfn(res);
 475
 476                         if (res_end < start)
 477                                 continue;
 478                         if (res_start < start)
 479                                 res_start = start;
 480                         if (res_start > end)
 481                                 res_start = end;
 482                         if (res_end > end)
 483                                 res_end = end;
 484                         if (res_start != start)
 485                                 free_area_high(start, res_start);
 486                         start = res_end;
 487                         if (start == end)
 488                                 break;
 489                 }
 490
 491                 /* And now free anything which remains */
 492                 if (start < end)
 493                         free_area_high(start, end);
 494         }
 495 #endif
 496 }
 497
 498 /*
 499  * mem_init() marks the free areas in the mem_map and tells us how much
 500  * memory is free.  This is done after various parts of the system have
 501  * claimed their memory after the kernel image.
 502  */
 503 void __init mem_init(void)
 504 {
 505 #ifdef CONFIG_HAVE_TCM
 506         /* These pointers are filled in on TCM detection */
 507         extern u32 dtcm_end;
 508         extern u32 itcm_end;
 509 #endif
 510
 511         set_max_mapnr(pfn_to_page(max_pfn) - mem_map);
 512
 513         /* this will put all unused low memory onto the freelists */
 514         free_unused_memmap();
 515         free_all_bootmem();
 516
 517 #ifdef CONFIG_SA1111
 518         /* now that our DMA memory is actually so designated, we can free it */
 519         free_reserved_area(__va(PHYS_OFFSET), swapper_pg_dir, -1, NULL);
 520 #endif
 521
 522         free_highpages();
 523
 524         mem_init_print_info(NULL);
 525
 526 #define MLK(b, t) b, t, ((t) - (b)) >> 10
 527 #define MLM(b, t) b, t, ((t) - (b)) >> 20
 528 #define MLK_ROUNDUP(b, t) b, t, DIV_ROUND_UP(((t) - (b)), SZ_1K)
 529
 530         pr_notice("Virtual kernel memory layout:\n"
 531                         "    vector  : 0x%08lx - 0x%08lx   (%4ld kB)\n"
 532 #ifdef CONFIG_HAVE_TCM
 533                         "    DTCM    : 0x%08lx - 0x%08lx   (%4ld kB)\n"
 534                         "    ITCM    : 0x%08lx - 0x%08lx   (%4ld kB)\n"
 535 #endif
 536                         "    fixmap  : 0x%08lx - 0x%08lx   (%4ld kB)\n"
 537                         "    vmalloc : 0x%08lx - 0x%08lx   (%4ld MB)\n"
 538                         "    lowmem  : 0x%08lx - 0x%08lx   (%4ld MB)\n"
 539 #ifdef CONFIG_HIGHMEM
 540                         "    pkmap   : 0x%08lx - 0x%08lx   (%4ld MB)\n"
 541 #endif
 542 #ifdef CONFIG_MODULES
 543                         "    modules : 0x%08lx - 0x%08lx   (%4ld MB)\n"
 544 #endif
 545                         "      .text : 0x%p" " - 0x%p" "   (%4td kB)\n"
 546                         "      .init : 0x%p" " - 0x%p" "   (%4td kB)\n"
 547                         "      .data : 0x%p" " - 0x%p" "   (%4td kB)\n"
 548                         "       .bss : 0x%p" " - 0x%p" "   (%4td kB)\n",
 549
 550                         MLK(VECTORS_BASE, VECTORS_BASE + PAGE_SIZE),
 551 #ifdef CONFIG_HAVE_TCM
 552                         MLK(DTCM_OFFSET, (unsigned long) dtcm_end),
 553                         MLK(ITCM_OFFSET, (unsigned long) itcm_end),
 554 #endif
 555                         MLK(FIXADDR_START, FIXADDR_END),
 556                         MLM(VMALLOC_START, VMALLOC_END),
 557                         MLM(PAGE_OFFSET, (unsigned long)high_memory),
 558 #ifdef CONFIG_HIGHMEM
 559                         MLM(PKMAP_BASE, (PKMAP_BASE) + (LAST_PKMAP) *
 560                                 (PAGE_SIZE)),
 561 #endif
 562 #ifdef CONFIG_MODULES
 563                         MLM(MODULES_VADDR, MODULES_END),
 564 #endif
 565
 566                         MLK_ROUNDUP(_text, _etext),
 567                         MLK_ROUNDUP(__init_begin, __init_end),
 568                         MLK_ROUNDUP(_sdata, _edata),
 569                         MLK_ROUNDUP(__bss_start, __bss_stop));
 570
 571 #undef MLK
 572 #undef MLM
 573 #undef MLK_ROUNDUP
 574
 575         /*
 576          * Check boundaries twice: Some fundamental inconsistencies can
 577          * be detected at build time already.
 578          */
 579 #ifdef CONFIG_MMU
 580         BUILD_BUG_ON(TASK_SIZE                          > MODULES_VADDR);
 581         BUG_ON(TASK_SIZE                                > MODULES_VADDR);
 582 #endif
 583
 584 #ifdef CONFIG_HIGHMEM
 585         BUILD_BUG_ON(PKMAP_BASE + LAST_PKMAP * PAGE_SIZE > PAGE_OFFSET);
 586         BUG_ON(PKMAP_BASE + LAST_PKMAP * PAGE_SIZE      > PAGE_OFFSET);
 587 #endif
 588
 589         if (PAGE_SIZE >= 16384 && get_num_physpages() <= 128) {
 590                 extern int sysctl_overcommit_memory;
 591                 /*
 592                  * On a machine this small we won't get
 593                  * anywhere without overcommit, so turn
 594                  * it on by default.
 595                  */
 596                 sysctl_overcommit_memory = OVERCOMMIT_ALWAYS;
 597         }
 598 }
 599
 600 #ifdef CONFIG_STRICT_KERNEL_RWX
 601 struct section_perm {
 602         const char *name;
 603         unsigned long start;
 604         unsigned long end;
 605         pmdval_t mask;
 606         pmdval_t prot;
 607         pmdval_t clear;
 608 };
 609
 610 /* First section-aligned location at or after __start_rodata. */
 611 extern char __start_rodata_section_aligned[];
 612
 613 static struct section_perm nx_perms[] = {
 614         /* Make pages tables, etc before _stext RW (set NX). */
 615         {
 616                 .name   = "pre-text NX",
 617                 .start  = PAGE_OFFSET,
 618                 .end    = (unsigned long)_stext,
 619                 .mask   = ~PMD_SECT_XN,
 620                 .prot   = PMD_SECT_XN,
 621         },
 622         /* Make init RW (set NX). */
 623         {
 624                 .name   = "init NX",
 625                 .start  = (unsigned long)__init_begin,
 626                 .end    = (unsigned long)_sdata,
 627                 .mask   = ~PMD_SECT_XN,
 628                 .prot   = PMD_SECT_XN,
 629         },
 630         /* Make rodata NX (set RO in ro_perms below). */
 631         {
 632                 .name   = "rodata NX",
 633                 .start  = (unsigned long)__start_rodata_section_aligned,
 634                 .end    = (unsigned long)__init_begin,
 635                 .mask   = ~PMD_SECT_XN,
 636                 .prot   = PMD_SECT_XN,
 637         },
 638 };
 639
 640 static struct section_perm ro_perms[] = {
 641         /* Make kernel code and rodata RX (set RO). */
 642         {
 643                 .name   = "text/rodata RO",
 644                 .start  = (unsigned long)_stext,
 645                 .end    = (unsigned long)__init_begin,
 646 #ifdef CONFIG_ARM_LPAE
 647                 .mask   = ~(L_PMD_SECT_RDONLY | PMD_SECT_AP2),
 648                 .prot   = L_PMD_SECT_RDONLY | PMD_SECT_AP2,
 649 #else
 650                 .mask   = ~(PMD_SECT_APX | PMD_SECT_AP_WRITE),
 651                 .prot   = PMD_SECT_APX | PMD_SECT_AP_WRITE,
 652                 .clear  = PMD_SECT_AP_WRITE,
 653 #endif
 654         },
 655 };
 656
 657 /*
 658  * Updates section permissions only for the current mm (sections are
 659  * copied into each mm). During startup, this is the init_mm. Is only
 660  * safe to be called with preemption disabled, as under stop_machine().
 661  */
 662 static inline void section_update(unsigned long addr, pmdval_t mask,
 663                                   pmdval_t prot, struct mm_struct *mm)
 664 {
 665         pmd_t *pmd;
 666
 667         pmd = pmd_offset(pud_offset(pgd_offset(mm, addr), addr), addr);
 668
 669 #ifdef CONFIG_ARM_LPAE
 670         pmd[0] = __pmd((pmd_val(pmd[0]) & mask) | prot);
 671 #else
 672         if (addr & SECTION_SIZE)
 673                 pmd[1] = __pmd((pmd_val(pmd[1]) & mask) | prot);
 674         else
 675                 pmd[0] = __pmd((pmd_val(pmd[0]) & mask) | prot);
 676 #endif
 677         flush_pmd_entry(pmd);
 678         local_flush_tlb_kernel_range(addr, addr + SECTION_SIZE);
 679 }
 680
 681 /* Make sure extended page tables are in use. */
 682 static inline bool arch_has_strict_perms(void)
 683 {
 684         if (cpu_architecture() < CPU_ARCH_ARMv6)
 685                 return false;
 686
 687         return !!(get_cr() & CR_XP);
 688 }
 689
 690 void set_section_perms(struct section_perm *perms, int n, bool set,
 691                         struct mm_struct *mm)
 692 {
 693         size_t i;
 694         unsigned long addr;
 695
 696         if (!arch_has_strict_perms())
 697                 return;
 698
 699         for (i = 0; i < n; i++) {
 700                 if (!IS_ALIGNED(perms[i].start, SECTION_SIZE) ||
 701                     !IS_ALIGNED(perms[i].end, SECTION_SIZE)) {
 702                         pr_err("BUG: %s section %lx-%lx not aligned to %lx\n",
 703                                 perms[i].name, perms[i].start, perms[i].end,
 704                                 SECTION_SIZE);
 705                         continue;
 706                 }
 707
 708                 for (addr = perms[i].start;
 709                      addr < perms[i].end;
 710                      addr += SECTION_SIZE)
 711                         section_update(addr, perms[i].mask,
 712                                 set ? perms[i].prot : perms[i].clear, mm);
 713         }
 714
 715 }
 716
 717 /**
 718  * update_sections_early intended to be called only through stop_machine
 719  * framework and executed by only one CPU while all other CPUs will spin and
 720  * wait, so no locking is required in this function.
 721  */
 722 static void update_sections_early(struct section_perm perms[], int n)
 723 {
 724         struct task_struct *t, *s;
 725
 726         for_each_process(t) {
 727                 if (t->flags & PF_KTHREAD)
 728                         continue;
 729                 for_each_thread(t, s)
 730                         if (s->mm)
 731                                 set_section_perms(perms, n, true, s->mm);
 732         }
 733         set_section_perms(perms, n, true, current->active_mm);
 734         set_section_perms(perms, n, true, &init_mm);
 735 }
 736
 737 static int __fix_kernmem_perms(void *unused)
 738 {
 739         update_sections_early(nx_perms, ARRAY_SIZE(nx_perms));
 740         return 0;
 741 }
 742
 743 static void fix_kernmem_perms(void)
 744 {
 745         stop_machine(__fix_kernmem_perms, NULL, NULL);
 746 }
 747
 748 static int __mark_rodata_ro(void *unused)
 749 {
 750         update_sections_early(ro_perms, ARRAY_SIZE(ro_perms));
 751         return 0;
 752 }
 753
 754 static int kernel_set_to_readonly __read_mostly;
 755
 756 void mark_rodata_ro(void)
 757 {
 758         kernel_set_to_readonly = 1;
 759         stop_machine(__mark_rodata_ro, NULL, NULL);
 760 }
 761
 762 void set_kernel_text_rw(void)
 763 {
 764         if (!kernel_set_to_readonly)
 765                 return;
 766
 767         set_section_perms(ro_perms, ARRAY_SIZE(ro_perms), false,
 768                                 current->active_mm);
 769 }
 770
 771 void set_kernel_text_ro(void)
 772 {
 773         if (!kernel_set_to_readonly)
 774                 return;
 775
 776         set_section_perms(ro_perms, ARRAY_SIZE(ro_perms), true,
 777                                 current->active_mm);
 778 }
 779
 780 #else
 781 static inline void fix_kernmem_perms(void) { }
 782 #endif /* CONFIG_STRICT_KERNEL_RWX */
 783
 784 void free_tcmmem(void)
 785 {
 786 #ifdef CONFIG_HAVE_TCM
 787         extern char __tcm_start, __tcm_end;
 788
 789         poison_init_mem(&__tcm_start, &__tcm_end - &__tcm_start);
 790         free_reserved_area(&__tcm_start, &__tcm_end, -1, "TCM link");
 791 #endif
 792 }
 793
 794 void free_initmem(void)
 795 {
 796         fix_kernmem_perms();
 797         free_tcmmem();
 798
 799         poison_init_mem(__init_begin, __init_end - __init_begin);
 800         if (!machine_is_integrator() && !machine_is_cintegrator())
 801                 free_initmem_default(-1);
 802 }
 803
 804 #ifdef CONFIG_BLK_DEV_INITRD
 805
 806 static int keep_initrd;
 807
 808 void free_initrd_mem(unsigned long start, unsigned long end)
 809 {
 810         if (!keep_initrd) {
 811                 if (start == initrd_start)
 812                         start = round_down(start, PAGE_SIZE);
 813                 if (end == initrd_end)
 814                         end = round_up(end, PAGE_SIZE);
 815
 816                 poison_init_mem((void *)start, PAGE_ALIGN(end) - start);
 817                 free_reserved_area((void *)start, (void *)end, -1, "initrd");
 818         }
 819 }
 820
 821 static int __init keepinitrd_setup(char *__unused)
 822 {
 823         keep_initrd = 1;
 824         return 1;
 825 }
 826
 827 __setup("keepinitrd", keepinitrd_setup);
 828 #endif