arch/arm/mm/init.c

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This source file includes following definitions.
__clear_cr
parse_tag_initrd
parse_tag_initrd2
find_limits
arm_adjust_dma_zone
setup_dma_zone
zone_sizes_init
pfn_valid
arm_memblock_steal
arm_initrd_init
check_cpu_icache_size
arm_memblock_init
bootmem_init
poison_init_mem
free_memmap
free_unused_memmap
free_area_high
free_highpages
mem_init
section_update
arch_has_strict_perms
set_section_perms
update_sections_early
__fix_kernmem_perms
fix_kernmem_perms
__mark_rodata_ro
mark_rodata_ro
set_kernel_text_rw
set_kernel_text_ro
fix_kernmem_perms
free_initmem
free_initrd_mem
   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  linux/arch/arm/mm/init.c
   4  *
   5  *  Copyright (C) 1995-2005 Russell King
   6  */
   7 #include <linux/kernel.h>
   8 #include <linux/errno.h>
   9 #include <linux/swap.h>
  10 #include <linux/init.h>
  11 #include <linux/mman.h>
  12 #include <linux/sched/signal.h>
  13 #include <linux/sched/task.h>
  14 #include <linux/export.h>
  15 #include <linux/nodemask.h>
  16 #include <linux/initrd.h>
  17 #include <linux/of_fdt.h>
  18 #include <linux/highmem.h>
  19 #include <linux/gfp.h>
  20 #include <linux/memblock.h>
  21 #include <linux/dma-contiguous.h>
  22 #include <linux/sizes.h>
  23 #include <linux/stop_machine.h>
  24 #include <linux/swiotlb.h>
  25 
  26 #include <asm/cp15.h>
  27 #include <asm/mach-types.h>
  28 #include <asm/memblock.h>
  29 #include <asm/memory.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 #include <asm/ptdump.h>
  37 
  38 #include <asm/mach/arch.h>
  39 #include <asm/mach/map.h>
  40 
  41 #include "mm.h"
  42 
  43 #ifdef CONFIG_CPU_CP15_MMU
  44 unsigned long __init __clear_cr(unsigned long mask)
  45 {
  46         cr_alignment = cr_alignment & ~mask;
  47         return cr_alignment;
  48 }
  49 #endif
  50 
  51 #ifdef CONFIG_BLK_DEV_INITRD
  52 static int __init parse_tag_initrd(const struct tag *tag)
  53 {
  54         pr_warn("ATAG_INITRD is deprecated; "
  55                 "please update your bootloader.\n");
  56         phys_initrd_start = __virt_to_phys(tag->u.initrd.start);
  57         phys_initrd_size = tag->u.initrd.size;
  58         return 0;
  59 }
  60 
  61 __tagtable(ATAG_INITRD, parse_tag_initrd);
  62 
  63 static int __init parse_tag_initrd2(const struct tag *tag)
  64 {
  65         phys_initrd_start = tag->u.initrd.start;
  66         phys_initrd_size = tag->u.initrd.size;
  67         return 0;
  68 }
  69 
  70 __tagtable(ATAG_INITRD2, parse_tag_initrd2);
  71 #endif
  72 
  73 static void __init find_limits(unsigned long *min, unsigned long *max_low,
  74                                unsigned long *max_high)
  75 {
  76         *max_low = PFN_DOWN(memblock_get_current_limit());
  77         *min = PFN_UP(memblock_start_of_DRAM());
  78         *max_high = PFN_DOWN(memblock_end_of_DRAM());
  79 }
  80 
  81 #ifdef CONFIG_ZONE_DMA
  82 
  83 phys_addr_t arm_dma_zone_size __read_mostly;
  84 EXPORT_SYMBOL(arm_dma_zone_size);
  85 
  86 /*
  87  * The DMA mask corresponding to the maximum bus address allocatable
  88  * using GFP_DMA.  The default here places no restriction on DMA
  89  * allocations.  This must be the smallest DMA mask in the system,
  90  * so a successful GFP_DMA allocation will always satisfy this.
  91  */
  92 phys_addr_t arm_dma_limit;
  93 unsigned long arm_dma_pfn_limit;
  94 
  95 static void __init arm_adjust_dma_zone(unsigned long *size, unsigned long *hole,
  96         unsigned long dma_size)
  97 {
  98         if (size[0] <= dma_size)
  99                 return;
 100 
 101         size[ZONE_NORMAL] = size[0] - dma_size;
 102         size[ZONE_DMA] = dma_size;
 103         hole[ZONE_NORMAL] = hole[0];
 104         hole[ZONE_DMA] = 0;
 105 }
 106 #endif
 107 
 108 void __init setup_dma_zone(const struct machine_desc *mdesc)
 109 {
 110 #ifdef CONFIG_ZONE_DMA
 111         if (mdesc->dma_zone_size) {
 112                 arm_dma_zone_size = mdesc->dma_zone_size;
 113                 arm_dma_limit = PHYS_OFFSET + arm_dma_zone_size - 1;
 114         } else
 115                 arm_dma_limit = 0xffffffff;
 116         arm_dma_pfn_limit = arm_dma_limit >> PAGE_SHIFT;
 117 #endif
 118 }
 119 
 120 static void __init zone_sizes_init(unsigned long min, unsigned long max_low,
 121         unsigned long max_high)
 122 {
 123         unsigned long zone_size[MAX_NR_ZONES], zhole_size[MAX_NR_ZONES];
 124         struct memblock_region *reg;
 125 
 126         /*
 127          * initialise the zones.
 128          */
 129         memset(zone_size, 0, sizeof(zone_size));
 130 
 131         /*
 132          * The memory size has already been determined.  If we need
 133          * to do anything fancy with the allocation of this memory
 134          * to the zones, now is the time to do it.
 135          */
 136         zone_size[0] = max_low - min;
 137 #ifdef CONFIG_HIGHMEM
 138         zone_size[ZONE_HIGHMEM] = max_high - max_low;
 139 #endif
 140 
 141         /*
 142          * Calculate the size of the holes.
 143          *  holes = node_size - sum(bank_sizes)
 144          */
 145         memcpy(zhole_size, zone_size, sizeof(zhole_size));
 146         for_each_memblock(memory, reg) {
 147                 unsigned long start = memblock_region_memory_base_pfn(reg);
 148                 unsigned long end = memblock_region_memory_end_pfn(reg);
 149 
 150                 if (start < max_low) {
 151                         unsigned long low_end = min(end, max_low);
 152                         zhole_size[0] -= low_end - start;
 153                 }
 154 #ifdef CONFIG_HIGHMEM
 155                 if (end > max_low) {
 156                         unsigned long high_start = max(start, max_low);
 157                         zhole_size[ZONE_HIGHMEM] -= end - high_start;
 158                 }
 159 #endif
 160         }
 161 
 162 #ifdef CONFIG_ZONE_DMA
 163         /*
 164          * Adjust the sizes according to any special requirements for
 165          * this machine type.
 166          */
 167         if (arm_dma_zone_size)
 168                 arm_adjust_dma_zone(zone_size, zhole_size,
 169                         arm_dma_zone_size >> PAGE_SHIFT);
 170 #endif
 171 
 172         free_area_init_node(0, zone_size, min, zhole_size);
 173 }
 174 
 175 #ifdef CONFIG_HAVE_ARCH_PFN_VALID
 176 int pfn_valid(unsigned long pfn)
 177 {
 178         phys_addr_t addr = __pfn_to_phys(pfn);
 179 
 180         if (__phys_to_pfn(addr) != pfn)
 181                 return 0;
 182 
 183         return memblock_is_map_memory(__pfn_to_phys(pfn));
 184 }
 185 EXPORT_SYMBOL(pfn_valid);
 186 #endif
 187 
 188 static bool arm_memblock_steal_permitted = true;
 189 
 190 phys_addr_t __init arm_memblock_steal(phys_addr_t size, phys_addr_t align)
 191 {
 192         phys_addr_t phys;
 193 
 194         BUG_ON(!arm_memblock_steal_permitted);
 195 
 196         phys = memblock_phys_alloc(size, align);
 197         if (!phys)
 198                 panic("Failed to steal %pa bytes at %pS\n",
 199                       &size, (void *)_RET_IP_);
 200 
 201         memblock_free(phys, size);
 202         memblock_remove(phys, size);
 203 
 204         return phys;
 205 }
 206 
 207 static void __init arm_initrd_init(void)
 208 {
 209 #ifdef CONFIG_BLK_DEV_INITRD
 210         phys_addr_t start;
 211         unsigned long size;
 212 
 213         initrd_start = initrd_end = 0;
 214 
 215         if (!phys_initrd_size)
 216                 return;
 217 
 218         /*
 219          * Round the memory region to page boundaries as per free_initrd_mem()
 220          * This allows us to detect whether the pages overlapping the initrd
 221          * are in use, but more importantly, reserves the entire set of pages
 222          * as we don't want these pages allocated for other purposes.
 223          */
 224         start = round_down(phys_initrd_start, PAGE_SIZE);
 225         size = phys_initrd_size + (phys_initrd_start - start);
 226         size = round_up(size, PAGE_SIZE);
 227 
 228         if (!memblock_is_region_memory(start, size)) {
 229                 pr_err("INITRD: 0x%08llx+0x%08lx is not a memory region - disabling initrd\n",
 230                        (u64)start, size);
 231                 return;
 232         }
 233 
 234         if (memblock_is_region_reserved(start, size)) {
 235                 pr_err("INITRD: 0x%08llx+0x%08lx overlaps in-use memory region - disabling initrd\n",
 236                        (u64)start, size);
 237                 return;
 238         }
 239 
 240         memblock_reserve(start, size);
 241 
 242         /* Now convert initrd to virtual addresses */
 243         initrd_start = __phys_to_virt(phys_initrd_start);
 244         initrd_end = initrd_start + phys_initrd_size;
 245 #endif
 246 }
 247 
 248 #ifdef CONFIG_CPU_ICACHE_MISMATCH_WORKAROUND
 249 void check_cpu_icache_size(int cpuid)
 250 {
 251         u32 size, ctr;
 252 
 253         asm("mrc p15, 0, %0, c0, c0, 1" : "=r" (ctr));
 254 
 255         size = 1 << ((ctr & 0xf) + 2);
 256         if (cpuid != 0 && icache_size != size)
 257                 pr_info("CPU%u: detected I-Cache line size mismatch, workaround enabled\n",
 258                         cpuid);
 259         if (icache_size > size)
 260                 icache_size = size;
 261 }
 262 #endif
 263 
 264 void __init arm_memblock_init(const struct machine_desc *mdesc)
 265 {
 266         /* Register the kernel text, kernel data and initrd with memblock. */
 267         memblock_reserve(__pa(KERNEL_START), KERNEL_END - KERNEL_START);
 268 
 269         arm_initrd_init();
 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         memblock_allow_resize();
 290 
 291         find_limits(&min_low_pfn, &max_low_pfn, &max_pfn);
 292 
 293         early_memtest((phys_addr_t)min_low_pfn << PAGE_SHIFT,
 294                       (phys_addr_t)max_low_pfn << PAGE_SHIFT);
 295 
 296         /*
 297          * Sparsemem tries to allocate bootmem in memory_present(),
 298          * so must be done after the fixed reservations
 299          */
 300         memblocks_present();
 301 
 302         /*
 303          * sparse_init() needs the bootmem allocator up and running.
 304          */
 305         sparse_init();
 306 
 307         /*
 308          * Now free the memory - free_area_init_node needs
 309          * the sparse mem_map arrays initialized by sparse_init()
 310          * for memmap_init_zone(), otherwise all PFNs are invalid.
 311          */
 312         zone_sizes_init(min_low_pfn, max_low_pfn, max_pfn);
 313 }
 314 
 315 /*
 316  * Poison init memory with an undefined instruction (ARM) or a branch to an
 317  * undefined instruction (Thumb).
 318  */
 319 static inline void poison_init_mem(void *s, size_t count)
 320 {
 321         u32 *p = (u32 *)s;
 322         for (; count != 0; count -= 4)
 323                 *p++ = 0xe7fddef0;
 324 }
 325 
 326 static inline void __init
 327 free_memmap(unsigned long start_pfn, unsigned long end_pfn)
 328 {
 329         struct page *start_pg, *end_pg;
 330         phys_addr_t pg, pgend;
 331 
 332         /*
 333          * Convert start_pfn/end_pfn to a struct page pointer.
 334          */
 335         start_pg = pfn_to_page(start_pfn - 1) + 1;
 336         end_pg = pfn_to_page(end_pfn - 1) + 1;
 337 
 338         /*
 339          * Convert to physical addresses, and
 340          * round start upwards and end downwards.
 341          */
 342         pg = PAGE_ALIGN(__pa(start_pg));
 343         pgend = __pa(end_pg) & PAGE_MASK;
 344 
 345         /*
 346          * If there are free pages between these,
 347          * free the section of the memmap array.
 348          */
 349         if (pg < pgend)
 350                 memblock_free_early(pg, pgend - pg);
 351 }
 352 
 353 /*
 354  * The mem_map array can get very big.  Free the unused area of the memory map.
 355  */
 356 static void __init free_unused_memmap(void)
 357 {
 358         unsigned long start, prev_end = 0;
 359         struct memblock_region *reg;
 360 
 361         /*
 362          * This relies on each bank being in address order.
 363          * The banks are sorted previously in bootmem_init().
 364          */
 365         for_each_memblock(memory, reg) {
 366                 start = memblock_region_memory_base_pfn(reg);
 367 
 368 #ifdef CONFIG_SPARSEMEM
 369                 /*
 370                  * Take care not to free memmap entries that don't exist
 371                  * due to SPARSEMEM sections which aren't present.
 372                  */
 373                 start = min(start,
 374                                  ALIGN(prev_end, PAGES_PER_SECTION));
 375 #else
 376                 /*
 377                  * Align down here since the VM subsystem insists that the
 378                  * memmap entries are valid from the bank start aligned to
 379                  * MAX_ORDER_NR_PAGES.
 380                  */
 381                 start = round_down(start, MAX_ORDER_NR_PAGES);
 382 #endif
 383                 /*
 384                  * If we had a previous bank, and there is a space
 385                  * between the current bank and the previous, free it.
 386                  */
 387                 if (prev_end && prev_end < start)
 388                         free_memmap(prev_end, start);
 389 
 390                 /*
 391                  * Align up here since the VM subsystem insists that the
 392                  * memmap entries are valid from the bank end aligned to
 393                  * MAX_ORDER_NR_PAGES.
 394                  */
 395                 prev_end = ALIGN(memblock_region_memory_end_pfn(reg),
 396                                  MAX_ORDER_NR_PAGES);
 397         }
 398 
 399 #ifdef CONFIG_SPARSEMEM
 400         if (!IS_ALIGNED(prev_end, PAGES_PER_SECTION))
 401                 free_memmap(prev_end,
 402                             ALIGN(prev_end, PAGES_PER_SECTION));
 403 #endif
 404 }
 405 
 406 #ifdef CONFIG_HIGHMEM
 407 static inline void free_area_high(unsigned long pfn, unsigned long end)
 408 {
 409         for (; pfn < end; pfn++)
 410                 free_highmem_page(pfn_to_page(pfn));
 411 }
 412 #endif
 413 
 414 static void __init free_highpages(void)
 415 {
 416 #ifdef CONFIG_HIGHMEM
 417         unsigned long max_low = max_low_pfn;
 418         struct memblock_region *mem, *res;
 419 
 420         /* set highmem page free */
 421         for_each_memblock(memory, mem) {
 422                 unsigned long start = memblock_region_memory_base_pfn(mem);
 423                 unsigned long end = memblock_region_memory_end_pfn(mem);
 424 
 425                 /* Ignore complete lowmem entries */
 426                 if (end <= max_low)
 427                         continue;
 428 
 429                 if (memblock_is_nomap(mem))
 430                         continue;
 431 
 432                 /* Truncate partial highmem entries */
 433                 if (start < max_low)
 434                         start = max_low;
 435 
 436                 /* Find and exclude any reserved regions */
 437                 for_each_memblock(reserved, res) {
 438                         unsigned long res_start, res_end;
 439 
 440                         res_start = memblock_region_reserved_base_pfn(res);
 441                         res_end = memblock_region_reserved_end_pfn(res);
 442 
 443                         if (res_end < start)
 444                                 continue;
 445                         if (res_start < start)
 446                                 res_start = start;
 447                         if (res_start > end)
 448                                 res_start = end;
 449                         if (res_end > end)
 450                                 res_end = end;
 451                         if (res_start != start)
 452                                 free_area_high(start, res_start);
 453                         start = res_end;
 454                         if (start == end)
 455                                 break;
 456                 }
 457 
 458                 /* And now free anything which remains */
 459                 if (start < end)
 460                         free_area_high(start, end);
 461         }
 462 #endif
 463 }
 464 
 465 /*
 466  * mem_init() marks the free areas in the mem_map and tells us how much
 467  * memory is free.  This is done after various parts of the system have
 468  * claimed their memory after the kernel image.
 469  */
 470 void __init mem_init(void)
 471 {
 472 #ifdef CONFIG_ARM_LPAE
 473         swiotlb_init(1);
 474 #endif
 475 
 476         set_max_mapnr(pfn_to_page(max_pfn) - mem_map);
 477 
 478         /* this will put all unused low memory onto the freelists */
 479         free_unused_memmap();
 480         memblock_free_all();
 481 
 482 #ifdef CONFIG_SA1111
 483         /* now that our DMA memory is actually so designated, we can free it */
 484         free_reserved_area(__va(PHYS_OFFSET), swapper_pg_dir, -1, NULL);
 485 #endif
 486 
 487         free_highpages();
 488 
 489         mem_init_print_info(NULL);
 490 
 491         /*
 492          * Check boundaries twice: Some fundamental inconsistencies can
 493          * be detected at build time already.
 494          */
 495 #ifdef CONFIG_MMU
 496         BUILD_BUG_ON(TASK_SIZE                          > MODULES_VADDR);
 497         BUG_ON(TASK_SIZE                                > MODULES_VADDR);
 498 #endif
 499 
 500 #ifdef CONFIG_HIGHMEM
 501         BUILD_BUG_ON(PKMAP_BASE + LAST_PKMAP * PAGE_SIZE > PAGE_OFFSET);
 502         BUG_ON(PKMAP_BASE + LAST_PKMAP * PAGE_SIZE      > PAGE_OFFSET);
 503 #endif
 504 }
 505 
 506 #ifdef CONFIG_STRICT_KERNEL_RWX
 507 struct section_perm {
 508         const char *name;
 509         unsigned long start;
 510         unsigned long end;
 511         pmdval_t mask;
 512         pmdval_t prot;
 513         pmdval_t clear;
 514 };
 515 
 516 /* First section-aligned location at or after __start_rodata. */
 517 extern char __start_rodata_section_aligned[];
 518 
 519 static struct section_perm nx_perms[] = {
 520         /* Make pages tables, etc before _stext RW (set NX). */
 521         {
 522                 .name   = "pre-text NX",
 523                 .start  = PAGE_OFFSET,
 524                 .end    = (unsigned long)_stext,
 525                 .mask   = ~PMD_SECT_XN,
 526                 .prot   = PMD_SECT_XN,
 527         },
 528         /* Make init RW (set NX). */
 529         {
 530                 .name   = "init NX",
 531                 .start  = (unsigned long)__init_begin,
 532                 .end    = (unsigned long)_sdata,
 533                 .mask   = ~PMD_SECT_XN,
 534                 .prot   = PMD_SECT_XN,
 535         },
 536         /* Make rodata NX (set RO in ro_perms below). */
 537         {
 538                 .name   = "rodata NX",
 539                 .start  = (unsigned long)__start_rodata_section_aligned,
 540                 .end    = (unsigned long)__init_begin,
 541                 .mask   = ~PMD_SECT_XN,
 542                 .prot   = PMD_SECT_XN,
 543         },
 544 };
 545 
 546 static struct section_perm ro_perms[] = {
 547         /* Make kernel code and rodata RX (set RO). */
 548         {
 549                 .name   = "text/rodata RO",
 550                 .start  = (unsigned long)_stext,
 551                 .end    = (unsigned long)__init_begin,
 552 #ifdef CONFIG_ARM_LPAE
 553                 .mask   = ~(L_PMD_SECT_RDONLY | PMD_SECT_AP2),
 554                 .prot   = L_PMD_SECT_RDONLY | PMD_SECT_AP2,
 555 #else
 556                 .mask   = ~(PMD_SECT_APX | PMD_SECT_AP_WRITE),
 557                 .prot   = PMD_SECT_APX | PMD_SECT_AP_WRITE,
 558                 .clear  = PMD_SECT_AP_WRITE,
 559 #endif
 560         },
 561 };
 562 
 563 /*
 564  * Updates section permissions only for the current mm (sections are
 565  * copied into each mm). During startup, this is the init_mm. Is only
 566  * safe to be called with preemption disabled, as under stop_machine().
 567  */
 568 static inline void section_update(unsigned long addr, pmdval_t mask,
 569                                   pmdval_t prot, struct mm_struct *mm)
 570 {
 571         pmd_t *pmd;
 572 
 573         pmd = pmd_offset(pud_offset(pgd_offset(mm, addr), addr), addr);
 574 
 575 #ifdef CONFIG_ARM_LPAE
 576         pmd[0] = __pmd((pmd_val(pmd[0]) & mask) | prot);
 577 #else
 578         if (addr & SECTION_SIZE)
 579                 pmd[1] = __pmd((pmd_val(pmd[1]) & mask) | prot);
 580         else
 581                 pmd[0] = __pmd((pmd_val(pmd[0]) & mask) | prot);
 582 #endif
 583         flush_pmd_entry(pmd);
 584         local_flush_tlb_kernel_range(addr, addr + SECTION_SIZE);
 585 }
 586 
 587 /* Make sure extended page tables are in use. */
 588 static inline bool arch_has_strict_perms(void)
 589 {
 590         if (cpu_architecture() < CPU_ARCH_ARMv6)
 591                 return false;
 592 
 593         return !!(get_cr() & CR_XP);
 594 }
 595 
 596 void set_section_perms(struct section_perm *perms, int n, bool set,
 597                         struct mm_struct *mm)
 598 {
 599         size_t i;
 600         unsigned long addr;
 601 
 602         if (!arch_has_strict_perms())
 603                 return;
 604 
 605         for (i = 0; i < n; i++) {
 606                 if (!IS_ALIGNED(perms[i].start, SECTION_SIZE) ||
 607                     !IS_ALIGNED(perms[i].end, SECTION_SIZE)) {
 608                         pr_err("BUG: %s section %lx-%lx not aligned to %lx\n",
 609                                 perms[i].name, perms[i].start, perms[i].end,
 610                                 SECTION_SIZE);
 611                         continue;
 612                 }
 613 
 614                 for (addr = perms[i].start;
 615                      addr < perms[i].end;
 616                      addr += SECTION_SIZE)
 617                         section_update(addr, perms[i].mask,
 618                                 set ? perms[i].prot : perms[i].clear, mm);
 619         }
 620 
 621 }
 622 
 623 /**
 624  * update_sections_early intended to be called only through stop_machine
 625  * framework and executed by only one CPU while all other CPUs will spin and
 626  * wait, so no locking is required in this function.
 627  */
 628 static void update_sections_early(struct section_perm perms[], int n)
 629 {
 630         struct task_struct *t, *s;
 631 
 632         for_each_process(t) {
 633                 if (t->flags & PF_KTHREAD)
 634                         continue;
 635                 for_each_thread(t, s)
 636                         if (s->mm)
 637                                 set_section_perms(perms, n, true, s->mm);
 638         }
 639         set_section_perms(perms, n, true, current->active_mm);
 640         set_section_perms(perms, n, true, &init_mm);
 641 }
 642 
 643 static int __fix_kernmem_perms(void *unused)
 644 {
 645         update_sections_early(nx_perms, ARRAY_SIZE(nx_perms));
 646         return 0;
 647 }
 648 
 649 static void fix_kernmem_perms(void)
 650 {
 651         stop_machine(__fix_kernmem_perms, NULL, NULL);
 652 }
 653 
 654 static int __mark_rodata_ro(void *unused)
 655 {
 656         update_sections_early(ro_perms, ARRAY_SIZE(ro_perms));
 657         return 0;
 658 }
 659 
 660 static int kernel_set_to_readonly __read_mostly;
 661 
 662 void mark_rodata_ro(void)
 663 {
 664         kernel_set_to_readonly = 1;
 665         stop_machine(__mark_rodata_ro, NULL, NULL);
 666         debug_checkwx();
 667 }
 668 
 669 void set_kernel_text_rw(void)
 670 {
 671         if (!kernel_set_to_readonly)
 672                 return;
 673 
 674         set_section_perms(ro_perms, ARRAY_SIZE(ro_perms), false,
 675                                 current->active_mm);
 676 }
 677 
 678 void set_kernel_text_ro(void)
 679 {
 680         if (!kernel_set_to_readonly)
 681                 return;
 682 
 683         set_section_perms(ro_perms, ARRAY_SIZE(ro_perms), true,
 684                                 current->active_mm);
 685 }
 686 
 687 #else
 688 static inline void fix_kernmem_perms(void) { }
 689 #endif /* CONFIG_STRICT_KERNEL_RWX */
 690 
 691 void free_initmem(void)
 692 {
 693         fix_kernmem_perms();
 694 
 695         poison_init_mem(__init_begin, __init_end - __init_begin);
 696         if (!machine_is_integrator() && !machine_is_cintegrator())
 697                 free_initmem_default(-1);
 698 }
 699 
 700 #ifdef CONFIG_BLK_DEV_INITRD
 701 void free_initrd_mem(unsigned long start, unsigned long end)
 702 {
 703         if (start == initrd_start)
 704                 start = round_down(start, PAGE_SIZE);
 705         if (end == initrd_end)
 706                 end = round_up(end, PAGE_SIZE);
 707 
 708         poison_init_mem((void *)start, PAGE_ALIGN(end) - start);
 709         free_reserved_area((void *)start, (void *)end, -1, "initrd");
 710 }
 711 #endif
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root/arch/arm/mm/init.c

DEFINITIONS
