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Linux/arch/arm/mm/init.c

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  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         return memblock_is_map_memory(__pfn_to_phys(pfn));
199 }
200 EXPORT_SYMBOL(pfn_valid);
201 #endif
202 
203 #ifndef CONFIG_SPARSEMEM
204 static void __init arm_memory_present(void)
205 {
206 }
207 #else
208 static void __init arm_memory_present(void)
209 {
210         struct memblock_region *reg;
211 
212         for_each_memblock(memory, reg)
213                 memory_present(0, memblock_region_memory_base_pfn(reg),
214                                memblock_region_memory_end_pfn(reg));
215 }
216 #endif
217 
218 static bool arm_memblock_steal_permitted = true;
219 
220 phys_addr_t __init arm_memblock_steal(phys_addr_t size, phys_addr_t align)
221 {
222         phys_addr_t phys;
223 
224         BUG_ON(!arm_memblock_steal_permitted);
225 
226         phys = memblock_alloc_base(size, align, MEMBLOCK_ALLOC_ANYWHERE);
227         memblock_free(phys, size);
228         memblock_remove(phys, size);
229 
230         return phys;
231 }
232 
233 static void __init arm_initrd_init(void)
234 {
235 #ifdef CONFIG_BLK_DEV_INITRD
236         phys_addr_t start;
237         unsigned long size;
238 
239         /* FDT scan will populate initrd_start */
240         if (initrd_start && !phys_initrd_size) {
241                 phys_initrd_start = __virt_to_phys(initrd_start);
242                 phys_initrd_size = initrd_end - initrd_start;
243         }
244 
245         initrd_start = initrd_end = 0;
246 
247         if (!phys_initrd_size)
248                 return;
249 
250         /*
251          * Round the memory region to page boundaries as per free_initrd_mem()
252          * This allows us to detect whether the pages overlapping the initrd
253          * are in use, but more importantly, reserves the entire set of pages
254          * as we don't want these pages allocated for other purposes.
255          */
256         start = round_down(phys_initrd_start, PAGE_SIZE);
257         size = phys_initrd_size + (phys_initrd_start - start);
258         size = round_up(size, PAGE_SIZE);
259 
260         if (!memblock_is_region_memory(start, size)) {
261                 pr_err("INITRD: 0x%08llx+0x%08lx is not a memory region - disabling initrd\n",
262                        (u64)start, size);
263                 return;
264         }
265 
266         if (memblock_is_region_reserved(start, size)) {
267                 pr_err("INITRD: 0x%08llx+0x%08lx overlaps in-use memory region - disabling initrd\n",
268                        (u64)start, size);
269                 return;
270         }
271 
272         memblock_reserve(start, size);
273 
274         /* Now convert initrd to virtual addresses */
275         initrd_start = __phys_to_virt(phys_initrd_start);
276         initrd_end = initrd_start + phys_initrd_size;
277 #endif
278 }
279 
280 void __init arm_memblock_init(const struct machine_desc *mdesc)
281 {
282         /* Register the kernel text, kernel data and initrd with memblock. */
283         memblock_reserve(__pa(KERNEL_START), KERNEL_END - KERNEL_START);
284 
285         arm_initrd_init();
286 
287         arm_mm_memblock_reserve();
288 
289         /* reserve any platform specific memblock areas */
290         if (mdesc->reserve)
291                 mdesc->reserve();
292 
293         early_init_fdt_reserve_self();
294         early_init_fdt_scan_reserved_mem();
295 
296         /* reserve memory for DMA contiguous allocations */
297         dma_contiguous_reserve(arm_dma_limit);
298 
299         arm_memblock_steal_permitted = false;
300         memblock_dump_all();
301 }
302 
303 void __init bootmem_init(void)
304 {
305         unsigned long min, max_low, max_high;
306 
307         memblock_allow_resize();
308         max_low = max_high = 0;
309 
310         find_limits(&min, &max_low, &max_high);
311 
312         early_memtest((phys_addr_t)min << PAGE_SHIFT,
313                       (phys_addr_t)max_low << PAGE_SHIFT);
314 
315         /*
316          * Sparsemem tries to allocate bootmem in memory_present(),
317          * so must be done after the fixed reservations
318          */
319         arm_memory_present();
320 
321         /*
322          * sparse_init() needs the bootmem allocator up and running.
323          */
324         sparse_init();
325 
326         /*
327          * Now free the memory - free_area_init_node needs
328          * the sparse mem_map arrays initialized by sparse_init()
329          * for memmap_init_zone(), otherwise all PFNs are invalid.
330          */
331         zone_sizes_init(min, max_low, max_high);
332 
333         /*
334          * This doesn't seem to be used by the Linux memory manager any
335          * more, but is used by ll_rw_block.  If we can get rid of it, we
336          * also get rid of some of the stuff above as well.
337          */
338         min_low_pfn = min;
339         max_low_pfn = max_low;
340         max_pfn = max_high;
341 }
342 
343 /*
344  * Poison init memory with an undefined instruction (ARM) or a branch to an
345  * undefined instruction (Thumb).
346  */
347 static inline void poison_init_mem(void *s, size_t count)
348 {
349         u32 *p = (u32 *)s;
350         for (; count != 0; count -= 4)
351                 *p++ = 0xe7fddef0;
352 }
353 
354 static inline void
355 free_memmap(unsigned long start_pfn, unsigned long end_pfn)
356 {
357         struct page *start_pg, *end_pg;
358         phys_addr_t pg, pgend;
359 
360         /*
361          * Convert start_pfn/end_pfn to a struct page pointer.
362          */
363         start_pg = pfn_to_page(start_pfn - 1) + 1;
364         end_pg = pfn_to_page(end_pfn - 1) + 1;
365 
366         /*
367          * Convert to physical addresses, and
368          * round start upwards and end downwards.
369          */
370         pg = PAGE_ALIGN(__pa(start_pg));
371         pgend = __pa(end_pg) & PAGE_MASK;
372 
373         /*
374          * If there are free pages between these,
375          * free the section of the memmap array.
376          */
377         if (pg < pgend)
378                 memblock_free_early(pg, pgend - pg);
379 }
380 
381 /*
382  * The mem_map array can get very big.  Free the unused area of the memory map.
383  */
384 static void __init free_unused_memmap(void)
385 {
386         unsigned long start, prev_end = 0;
387         struct memblock_region *reg;
388 
389         /*
390          * This relies on each bank being in address order.
391          * The banks are sorted previously in bootmem_init().
392          */
393         for_each_memblock(memory, reg) {
394                 start = memblock_region_memory_base_pfn(reg);
395 
396 #ifdef CONFIG_SPARSEMEM
397                 /*
398                  * Take care not to free memmap entries that don't exist
399                  * due to SPARSEMEM sections which aren't present.
400                  */
401                 start = min(start,
402                                  ALIGN(prev_end, PAGES_PER_SECTION));
403 #else
404                 /*
405                  * Align down here since the VM subsystem insists that the
406                  * memmap entries are valid from the bank start aligned to
407                  * MAX_ORDER_NR_PAGES.
408                  */
409                 start = round_down(start, MAX_ORDER_NR_PAGES);
410 #endif
411                 /*
412                  * If we had a previous bank, and there is a space
413                  * between the current bank and the previous, free it.
414                  */
415                 if (prev_end && prev_end < start)
416                         free_memmap(prev_end, start);
417 
418                 /*
419                  * Align up here since the VM subsystem insists that the
420                  * memmap entries are valid from the bank end aligned to
421                  * MAX_ORDER_NR_PAGES.
422                  */
423                 prev_end = ALIGN(memblock_region_memory_end_pfn(reg),
424                                  MAX_ORDER_NR_PAGES);
425         }
426 
427 #ifdef CONFIG_SPARSEMEM
428         if (!IS_ALIGNED(prev_end, PAGES_PER_SECTION))
429                 free_memmap(prev_end,
430                             ALIGN(prev_end, PAGES_PER_SECTION));
431 #endif
432 }
433 
434 #ifdef CONFIG_HIGHMEM
435 static inline void free_area_high(unsigned long pfn, unsigned long end)
436 {
437         for (; pfn < end; pfn++)
438                 free_highmem_page(pfn_to_page(pfn));
439 }
440 #endif
441 
442 static void __init free_highpages(void)
443 {
444 #ifdef CONFIG_HIGHMEM
445         unsigned long max_low = max_low_pfn;
446         struct memblock_region *mem, *res;
447 
448         /* set highmem page free */
449         for_each_memblock(memory, mem) {
450                 unsigned long start = memblock_region_memory_base_pfn(mem);
451                 unsigned long end = memblock_region_memory_end_pfn(mem);
452 
453                 /* Ignore complete lowmem entries */
454                 if (end <= max_low)
455                         continue;
456 
457                 if (memblock_is_nomap(mem))
458                         continue;
459 
460                 /* Truncate partial highmem entries */
461                 if (start < max_low)
462                         start = max_low;
463 
464                 /* Find and exclude any reserved regions */
465                 for_each_memblock(reserved, res) {
466                         unsigned long res_start, res_end;
467 
468                         res_start = memblock_region_reserved_base_pfn(res);
469                         res_end = memblock_region_reserved_end_pfn(res);
470 
471                         if (res_end < start)
472                                 continue;
473                         if (res_start < start)
474                                 res_start = start;
475                         if (res_start > end)
476                                 res_start = end;
477                         if (res_end > end)
478                                 res_end = end;
479                         if (res_start != start)
480                                 free_area_high(start, res_start);
481                         start = res_end;
482                         if (start == end)
483                                 break;
484                 }
485 
486                 /* And now free anything which remains */
487                 if (start < end)
488                         free_area_high(start, end);
489         }
490 #endif
491 }
492 
493 /*
494  * mem_init() marks the free areas in the mem_map and tells us how much
495  * memory is free.  This is done after various parts of the system have
496  * claimed their memory after the kernel image.
497  */
498 void __init mem_init(void)
499 {
500 #ifdef CONFIG_HAVE_TCM
501         /* These pointers are filled in on TCM detection */
502         extern u32 dtcm_end;
503         extern u32 itcm_end;
504 #endif
505 
506         set_max_mapnr(pfn_to_page(max_pfn) - mem_map);
507 
508         /* this will put all unused low memory onto the freelists */
509         free_unused_memmap();
510         free_all_bootmem();
511 
512 #ifdef CONFIG_SA1111
513         /* now that our DMA memory is actually so designated, we can free it */
514         free_reserved_area(__va(PHYS_OFFSET), swapper_pg_dir, -1, NULL);
515 #endif
516 
517         free_highpages();
518 
519         mem_init_print_info(NULL);
520 
521 #define MLK(b, t) b, t, ((t) - (b)) >> 10
522 #define MLM(b, t) b, t, ((t) - (b)) >> 20
523 #define MLK_ROUNDUP(b, t) b, t, DIV_ROUND_UP(((t) - (b)), SZ_1K)
524 
525         pr_notice("Virtual kernel memory layout:\n"
526                         "    vector  : 0x%08lx - 0x%08lx   (%4ld kB)\n"
527 #ifdef CONFIG_HAVE_TCM
528                         "    DTCM    : 0x%08lx - 0x%08lx   (%4ld kB)\n"
529                         "    ITCM    : 0x%08lx - 0x%08lx   (%4ld kB)\n"
530 #endif
531                         "    fixmap  : 0x%08lx - 0x%08lx   (%4ld kB)\n"
532                         "    vmalloc : 0x%08lx - 0x%08lx   (%4ld MB)\n"
533                         "    lowmem  : 0x%08lx - 0x%08lx   (%4ld MB)\n"
534 #ifdef CONFIG_HIGHMEM
535                         "    pkmap   : 0x%08lx - 0x%08lx   (%4ld MB)\n"
536 #endif
537 #ifdef CONFIG_MODULES
538                         "    modules : 0x%08lx - 0x%08lx   (%4ld MB)\n"
539 #endif
540                         "      .text : 0x%p" " - 0x%p" "   (%4td kB)\n"
541                         "      .init : 0x%p" " - 0x%p" "   (%4td kB)\n"
542                         "      .data : 0x%p" " - 0x%p" "   (%4td kB)\n"
543                         "       .bss : 0x%p" " - 0x%p" "   (%4td kB)\n",
544 
545                         MLK(VECTORS_BASE, VECTORS_BASE + PAGE_SIZE),
546 #ifdef CONFIG_HAVE_TCM
547                         MLK(DTCM_OFFSET, (unsigned long) dtcm_end),
548                         MLK(ITCM_OFFSET, (unsigned long) itcm_end),
549 #endif
550                         MLK(FIXADDR_START, FIXADDR_END),
551                         MLM(VMALLOC_START, VMALLOC_END),
552                         MLM(PAGE_OFFSET, (unsigned long)high_memory),
553 #ifdef CONFIG_HIGHMEM
554                         MLM(PKMAP_BASE, (PKMAP_BASE) + (LAST_PKMAP) *
555                                 (PAGE_SIZE)),
556 #endif
557 #ifdef CONFIG_MODULES
558                         MLM(MODULES_VADDR, MODULES_END),
559 #endif
560 
561                         MLK_ROUNDUP(_text, _etext),
562                         MLK_ROUNDUP(__init_begin, __init_end),
563                         MLK_ROUNDUP(_sdata, _edata),
564                         MLK_ROUNDUP(__bss_start, __bss_stop));
565 
566 #undef MLK
567 #undef MLM
568 #undef MLK_ROUNDUP
569 
570         /*
571          * Check boundaries twice: Some fundamental inconsistencies can
572          * be detected at build time already.
573          */
574 #ifdef CONFIG_MMU
575         BUILD_BUG_ON(TASK_SIZE                          > MODULES_VADDR);
576         BUG_ON(TASK_SIZE                                > MODULES_VADDR);
577 #endif
578 
579 #ifdef CONFIG_HIGHMEM
580         BUILD_BUG_ON(PKMAP_BASE + LAST_PKMAP * PAGE_SIZE > PAGE_OFFSET);
581         BUG_ON(PKMAP_BASE + LAST_PKMAP * PAGE_SIZE      > PAGE_OFFSET);
582 #endif
583 
584         if (PAGE_SIZE >= 16384 && get_num_physpages() <= 128) {
585                 extern int sysctl_overcommit_memory;
586                 /*
587                  * On a machine this small we won't get
588                  * anywhere without overcommit, so turn
589                  * it on by default.
590                  */
591                 sysctl_overcommit_memory = OVERCOMMIT_ALWAYS;
592         }
593 }
594 
595 #ifdef CONFIG_STRICT_KERNEL_RWX
596 struct section_perm {
597         const char *name;
598         unsigned long start;
599         unsigned long end;
600         pmdval_t mask;
601         pmdval_t prot;
602         pmdval_t clear;
603 };
604 
605 /* First section-aligned location at or after __start_rodata. */
606 extern char __start_rodata_section_aligned[];
607 
608 static struct section_perm nx_perms[] = {
609         /* Make pages tables, etc before _stext RW (set NX). */
610         {
611                 .name   = "pre-text NX",
612                 .start  = PAGE_OFFSET,
613                 .end    = (unsigned long)_stext,
614                 .mask   = ~PMD_SECT_XN,
615                 .prot   = PMD_SECT_XN,
616         },
617         /* Make init RW (set NX). */
618         {
619                 .name   = "init NX",
620                 .start  = (unsigned long)__init_begin,
621                 .end    = (unsigned long)_sdata,
622                 .mask   = ~PMD_SECT_XN,
623                 .prot   = PMD_SECT_XN,
624         },
625         /* Make rodata NX (set RO in ro_perms below). */
626         {
627                 .name   = "rodata NX",
628                 .start  = (unsigned long)__start_rodata_section_aligned,
629                 .end    = (unsigned long)__init_begin,
630                 .mask   = ~PMD_SECT_XN,
631                 .prot   = PMD_SECT_XN,
632         },
633 };
634 
635 static struct section_perm ro_perms[] = {
636         /* Make kernel code and rodata RX (set RO). */
637         {
638                 .name   = "text/rodata RO",
639                 .start  = (unsigned long)_stext,
640                 .end    = (unsigned long)__init_begin,
641 #ifdef CONFIG_ARM_LPAE
642                 .mask   = ~L_PMD_SECT_RDONLY,
643                 .prot   = L_PMD_SECT_RDONLY,
644 #else
645                 .mask   = ~(PMD_SECT_APX | PMD_SECT_AP_WRITE),
646                 .prot   = PMD_SECT_APX | PMD_SECT_AP_WRITE,
647                 .clear  = PMD_SECT_AP_WRITE,
648 #endif
649         },
650 };
651 
652 /*
653  * Updates section permissions only for the current mm (sections are
654  * copied into each mm). During startup, this is the init_mm. Is only
655  * safe to be called with preemption disabled, as under stop_machine().
656  */
657 static inline void section_update(unsigned long addr, pmdval_t mask,
658                                   pmdval_t prot, struct mm_struct *mm)
659 {
660         pmd_t *pmd;
661 
662         pmd = pmd_offset(pud_offset(pgd_offset(mm, addr), addr), addr);
663 
664 #ifdef CONFIG_ARM_LPAE
665         pmd[0] = __pmd((pmd_val(pmd[0]) & mask) | prot);
666 #else
667         if (addr & SECTION_SIZE)
668                 pmd[1] = __pmd((pmd_val(pmd[1]) & mask) | prot);
669         else
670                 pmd[0] = __pmd((pmd_val(pmd[0]) & mask) | prot);
671 #endif
672         flush_pmd_entry(pmd);
673         local_flush_tlb_kernel_range(addr, addr + SECTION_SIZE);
674 }
675 
676 /* Make sure extended page tables are in use. */
677 static inline bool arch_has_strict_perms(void)
678 {
679         if (cpu_architecture() < CPU_ARCH_ARMv6)
680                 return false;
681 
682         return !!(get_cr() & CR_XP);
683 }
684 
685 void set_section_perms(struct section_perm *perms, int n, bool set,
686                         struct mm_struct *mm)
687 {
688         size_t i;
689         unsigned long addr;
690 
691         if (!arch_has_strict_perms())
692                 return;
693 
694         for (i = 0; i < n; i++) {
695                 if (!IS_ALIGNED(perms[i].start, SECTION_SIZE) ||
696                     !IS_ALIGNED(perms[i].end, SECTION_SIZE)) {
697                         pr_err("BUG: %s section %lx-%lx not aligned to %lx\n",
698                                 perms[i].name, perms[i].start, perms[i].end,
699                                 SECTION_SIZE);
700                         continue;
701                 }
702 
703                 for (addr = perms[i].start;
704                      addr < perms[i].end;
705                      addr += SECTION_SIZE)
706                         section_update(addr, perms[i].mask,
707                                 set ? perms[i].prot : perms[i].clear, mm);
708         }
709 
710 }
711 
712 /**
713  * update_sections_early intended to be called only through stop_machine
714  * framework and executed by only one CPU while all other CPUs will spin and
715  * wait, so no locking is required in this function.
716  */
717 static void update_sections_early(struct section_perm perms[], int n)
718 {
719         struct task_struct *t, *s;
720 
721         for_each_process(t) {
722                 if (t->flags & PF_KTHREAD)
723                         continue;
724                 for_each_thread(t, s)
725                         set_section_perms(perms, n, true, s->mm);
726         }
727         set_section_perms(perms, n, true, current->active_mm);
728         set_section_perms(perms, n, true, &init_mm);
729 }
730 
731 static int __fix_kernmem_perms(void *unused)
732 {
733         update_sections_early(nx_perms, ARRAY_SIZE(nx_perms));
734         return 0;
735 }
736 
737 static void fix_kernmem_perms(void)
738 {
739         stop_machine(__fix_kernmem_perms, NULL, NULL);
740 }
741 
742 static int __mark_rodata_ro(void *unused)
743 {
744         update_sections_early(ro_perms, ARRAY_SIZE(ro_perms));
745         return 0;
746 }
747 
748 void mark_rodata_ro(void)
749 {
750         stop_machine(__mark_rodata_ro, NULL, NULL);
751 }
752 
753 void set_kernel_text_rw(void)
754 {
755         set_section_perms(ro_perms, ARRAY_SIZE(ro_perms), false,
756                                 current->active_mm);
757 }
758 
759 void set_kernel_text_ro(void)
760 {
761         set_section_perms(ro_perms, ARRAY_SIZE(ro_perms), true,
762                                 current->active_mm);
763 }
764 
765 #else
766 static inline void fix_kernmem_perms(void) { }
767 #endif /* CONFIG_STRICT_KERNEL_RWX */
768 
769 void free_tcmmem(void)
770 {
771 #ifdef CONFIG_HAVE_TCM
772         extern char __tcm_start, __tcm_end;
773 
774         poison_init_mem(&__tcm_start, &__tcm_end - &__tcm_start);
775         free_reserved_area(&__tcm_start, &__tcm_end, -1, "TCM link");
776 #endif
777 }
778 
779 void free_initmem(void)
780 {
781         fix_kernmem_perms();
782         free_tcmmem();
783 
784         poison_init_mem(__init_begin, __init_end - __init_begin);
785         if (!machine_is_integrator() && !machine_is_cintegrator())
786                 free_initmem_default(-1);
787 }
788 
789 #ifdef CONFIG_BLK_DEV_INITRD
790 
791 static int keep_initrd;
792 
793 void free_initrd_mem(unsigned long start, unsigned long end)
794 {
795         if (!keep_initrd) {
796                 if (start == initrd_start)
797                         start = round_down(start, PAGE_SIZE);
798                 if (end == initrd_end)
799                         end = round_up(end, PAGE_SIZE);
800 
801                 poison_init_mem((void *)start, PAGE_ALIGN(end) - start);
802                 free_reserved_area((void *)start, (void *)end, -1, "initrd");
803         }
804 }
805 
806 static int __init keepinitrd_setup(char *__unused)
807 {
808         keep_initrd = 1;
809         return 1;
810 }
811 
812 __setup("keepinitrd", keepinitrd_setup);
813 #endif
814 

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