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Linux/arch/arm64/mm/mmu.c

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  1 /*
  2  * Based on arch/arm/mm/mmu.c
  3  *
  4  * Copyright (C) 1995-2005 Russell King
  5  * Copyright (C) 2012 ARM Ltd.
  6  *
  7  * This program is free software; you can redistribute it and/or modify
  8  * it under the terms of the GNU General Public License version 2 as
  9  * published by the Free Software Foundation.
 10  *
 11  * This program is distributed in the hope that it will be useful,
 12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
 13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 14  * GNU General Public License for more details.
 15  *
 16  * You should have received a copy of the GNU General Public License
 17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 18  */
 19 
 20 #include <linux/export.h>
 21 #include <linux/kernel.h>
 22 #include <linux/errno.h>
 23 #include <linux/init.h>
 24 #include <linux/libfdt.h>
 25 #include <linux/mman.h>
 26 #include <linux/nodemask.h>
 27 #include <linux/memblock.h>
 28 #include <linux/fs.h>
 29 #include <linux/io.h>
 30 #include <linux/slab.h>
 31 #include <linux/stop_machine.h>
 32 
 33 #include <asm/barrier.h>
 34 #include <asm/cputype.h>
 35 #include <asm/fixmap.h>
 36 #include <asm/kasan.h>
 37 #include <asm/kernel-pgtable.h>
 38 #include <asm/sections.h>
 39 #include <asm/setup.h>
 40 #include <asm/sizes.h>
 41 #include <asm/tlb.h>
 42 #include <asm/memblock.h>
 43 #include <asm/mmu_context.h>
 44 
 45 #include "mm.h"
 46 
 47 u64 idmap_t0sz = TCR_T0SZ(VA_BITS);
 48 
 49 u64 kimage_voffset __read_mostly;
 50 EXPORT_SYMBOL(kimage_voffset);
 51 
 52 /*
 53  * Empty_zero_page is a special page that is used for zero-initialized data
 54  * and COW.
 55  */
 56 unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] __page_aligned_bss;
 57 EXPORT_SYMBOL(empty_zero_page);
 58 
 59 static pte_t bm_pte[PTRS_PER_PTE] __page_aligned_bss;
 60 static pmd_t bm_pmd[PTRS_PER_PMD] __page_aligned_bss __maybe_unused;
 61 static pud_t bm_pud[PTRS_PER_PUD] __page_aligned_bss __maybe_unused;
 62 
 63 pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
 64                               unsigned long size, pgprot_t vma_prot)
 65 {
 66         if (!pfn_valid(pfn))
 67                 return pgprot_noncached(vma_prot);
 68         else if (file->f_flags & O_SYNC)
 69                 return pgprot_writecombine(vma_prot);
 70         return vma_prot;
 71 }
 72 EXPORT_SYMBOL(phys_mem_access_prot);
 73 
 74 static phys_addr_t __init early_pgtable_alloc(void)
 75 {
 76         phys_addr_t phys;
 77         void *ptr;
 78 
 79         phys = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
 80 
 81         /*
 82          * The FIX_{PGD,PUD,PMD} slots may be in active use, but the FIX_PTE
 83          * slot will be free, so we can (ab)use the FIX_PTE slot to initialise
 84          * any level of table.
 85          */
 86         ptr = pte_set_fixmap(phys);
 87 
 88         memset(ptr, 0, PAGE_SIZE);
 89 
 90         /*
 91          * Implicit barriers also ensure the zeroed page is visible to the page
 92          * table walker
 93          */
 94         pte_clear_fixmap();
 95 
 96         return phys;
 97 }
 98 
 99 static void alloc_init_pte(pmd_t *pmd, unsigned long addr,
100                                   unsigned long end, unsigned long pfn,
101                                   pgprot_t prot,
102                                   phys_addr_t (*pgtable_alloc)(void))
103 {
104         pte_t *pte;
105 
106         BUG_ON(pmd_sect(*pmd));
107         if (pmd_none(*pmd)) {
108                 phys_addr_t pte_phys;
109                 BUG_ON(!pgtable_alloc);
110                 pte_phys = pgtable_alloc();
111                 pte = pte_set_fixmap(pte_phys);
112                 __pmd_populate(pmd, pte_phys, PMD_TYPE_TABLE);
113                 pte_clear_fixmap();
114         }
115         BUG_ON(pmd_bad(*pmd));
116 
117         pte = pte_set_fixmap_offset(pmd, addr);
118         do {
119                 set_pte(pte, pfn_pte(pfn, prot));
120                 pfn++;
121         } while (pte++, addr += PAGE_SIZE, addr != end);
122 
123         pte_clear_fixmap();
124 }
125 
126 static void alloc_init_pmd(pud_t *pud, unsigned long addr, unsigned long end,
127                                   phys_addr_t phys, pgprot_t prot,
128                                   phys_addr_t (*pgtable_alloc)(void),
129                                   bool allow_block_mappings)
130 {
131         pmd_t *pmd;
132         unsigned long next;
133 
134         /*
135          * Check for initial section mappings in the pgd/pud and remove them.
136          */
137         BUG_ON(pud_sect(*pud));
138         if (pud_none(*pud)) {
139                 phys_addr_t pmd_phys;
140                 BUG_ON(!pgtable_alloc);
141                 pmd_phys = pgtable_alloc();
142                 pmd = pmd_set_fixmap(pmd_phys);
143                 __pud_populate(pud, pmd_phys, PUD_TYPE_TABLE);
144                 pmd_clear_fixmap();
145         }
146         BUG_ON(pud_bad(*pud));
147 
148         pmd = pmd_set_fixmap_offset(pud, addr);
149         do {
150                 next = pmd_addr_end(addr, end);
151                 /* try section mapping first */
152                 if (((addr | next | phys) & ~SECTION_MASK) == 0 &&
153                       allow_block_mappings) {
154                         pmd_t old_pmd =*pmd;
155                         pmd_set_huge(pmd, phys, prot);
156                         /*
157                          * Check for previous table entries created during
158                          * boot (__create_page_tables) and flush them.
159                          */
160                         if (!pmd_none(old_pmd)) {
161                                 flush_tlb_all();
162                                 if (pmd_table(old_pmd)) {
163                                         phys_addr_t table = pmd_page_paddr(old_pmd);
164                                         if (!WARN_ON_ONCE(slab_is_available()))
165                                                 memblock_free(table, PAGE_SIZE);
166                                 }
167                         }
168                 } else {
169                         alloc_init_pte(pmd, addr, next, __phys_to_pfn(phys),
170                                        prot, pgtable_alloc);
171                 }
172                 phys += next - addr;
173         } while (pmd++, addr = next, addr != end);
174 
175         pmd_clear_fixmap();
176 }
177 
178 static inline bool use_1G_block(unsigned long addr, unsigned long next,
179                         unsigned long phys)
180 {
181         if (PAGE_SHIFT != 12)
182                 return false;
183 
184         if (((addr | next | phys) & ~PUD_MASK) != 0)
185                 return false;
186 
187         return true;
188 }
189 
190 static void alloc_init_pud(pgd_t *pgd, unsigned long addr, unsigned long end,
191                                   phys_addr_t phys, pgprot_t prot,
192                                   phys_addr_t (*pgtable_alloc)(void),
193                                   bool allow_block_mappings)
194 {
195         pud_t *pud;
196         unsigned long next;
197 
198         if (pgd_none(*pgd)) {
199                 phys_addr_t pud_phys;
200                 BUG_ON(!pgtable_alloc);
201                 pud_phys = pgtable_alloc();
202                 __pgd_populate(pgd, pud_phys, PUD_TYPE_TABLE);
203         }
204         BUG_ON(pgd_bad(*pgd));
205 
206         pud = pud_set_fixmap_offset(pgd, addr);
207         do {
208                 next = pud_addr_end(addr, end);
209 
210                 /*
211                  * For 4K granule only, attempt to put down a 1GB block
212                  */
213                 if (use_1G_block(addr, next, phys) && allow_block_mappings) {
214                         pud_t old_pud = *pud;
215                         pud_set_huge(pud, phys, prot);
216 
217                         /*
218                          * If we have an old value for a pud, it will
219                          * be pointing to a pmd table that we no longer
220                          * need (from swapper_pg_dir).
221                          *
222                          * Look up the old pmd table and free it.
223                          */
224                         if (!pud_none(old_pud)) {
225                                 flush_tlb_all();
226                                 if (pud_table(old_pud)) {
227                                         phys_addr_t table = pud_page_paddr(old_pud);
228                                         if (!WARN_ON_ONCE(slab_is_available()))
229                                                 memblock_free(table, PAGE_SIZE);
230                                 }
231                         }
232                 } else {
233                         alloc_init_pmd(pud, addr, next, phys, prot,
234                                        pgtable_alloc, allow_block_mappings);
235                 }
236                 phys += next - addr;
237         } while (pud++, addr = next, addr != end);
238 
239         pud_clear_fixmap();
240 }
241 
242 static void __create_pgd_mapping(pgd_t *pgdir, phys_addr_t phys,
243                                  unsigned long virt, phys_addr_t size,
244                                  pgprot_t prot,
245                                  phys_addr_t (*pgtable_alloc)(void),
246                                  bool allow_block_mappings)
247 {
248         unsigned long addr, length, end, next;
249         pgd_t *pgd = pgd_offset_raw(pgdir, virt);
250 
251         /*
252          * If the virtual and physical address don't have the same offset
253          * within a page, we cannot map the region as the caller expects.
254          */
255         if (WARN_ON((phys ^ virt) & ~PAGE_MASK))
256                 return;
257 
258         phys &= PAGE_MASK;
259         addr = virt & PAGE_MASK;
260         length = PAGE_ALIGN(size + (virt & ~PAGE_MASK));
261 
262         end = addr + length;
263         do {
264                 next = pgd_addr_end(addr, end);
265                 alloc_init_pud(pgd, addr, next, phys, prot, pgtable_alloc,
266                                allow_block_mappings);
267                 phys += next - addr;
268         } while (pgd++, addr = next, addr != end);
269 }
270 
271 static phys_addr_t pgd_pgtable_alloc(void)
272 {
273         void *ptr = (void *)__get_free_page(PGALLOC_GFP);
274         if (!ptr || !pgtable_page_ctor(virt_to_page(ptr)))
275                 BUG();
276 
277         /* Ensure the zeroed page is visible to the page table walker */
278         dsb(ishst);
279         return __pa(ptr);
280 }
281 
282 /*
283  * This function can only be used to modify existing table entries,
284  * without allocating new levels of table. Note that this permits the
285  * creation of new section or page entries.
286  */
287 static void __init create_mapping_noalloc(phys_addr_t phys, unsigned long virt,
288                                   phys_addr_t size, pgprot_t prot)
289 {
290         if (virt < VMALLOC_START) {
291                 pr_warn("BUG: not creating mapping for %pa at 0x%016lx - outside kernel range\n",
292                         &phys, virt);
293                 return;
294         }
295         __create_pgd_mapping(init_mm.pgd, phys, virt, size, prot, NULL, true);
296 }
297 
298 void __init create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys,
299                                unsigned long virt, phys_addr_t size,
300                                pgprot_t prot, bool allow_block_mappings)
301 {
302         BUG_ON(mm == &init_mm);
303 
304         __create_pgd_mapping(mm->pgd, phys, virt, size, prot,
305                              pgd_pgtable_alloc, allow_block_mappings);
306 }
307 
308 static void create_mapping_late(phys_addr_t phys, unsigned long virt,
309                                   phys_addr_t size, pgprot_t prot)
310 {
311         if (virt < VMALLOC_START) {
312                 pr_warn("BUG: not creating mapping for %pa at 0x%016lx - outside kernel range\n",
313                         &phys, virt);
314                 return;
315         }
316 
317         __create_pgd_mapping(init_mm.pgd, phys, virt, size, prot,
318                              NULL, !debug_pagealloc_enabled());
319 }
320 
321 static void __init __map_memblock(pgd_t *pgd, phys_addr_t start, phys_addr_t end)
322 {
323         unsigned long kernel_start = __pa(_text);
324         unsigned long kernel_end = __pa(__init_begin);
325 
326         /*
327          * Take care not to create a writable alias for the
328          * read-only text and rodata sections of the kernel image.
329          */
330 
331         /* No overlap with the kernel text/rodata */
332         if (end < kernel_start || start >= kernel_end) {
333                 __create_pgd_mapping(pgd, start, __phys_to_virt(start),
334                                      end - start, PAGE_KERNEL,
335                                      early_pgtable_alloc,
336                                      !debug_pagealloc_enabled());
337                 return;
338         }
339 
340         /*
341          * This block overlaps the kernel text/rodata mappings.
342          * Map the portion(s) which don't overlap.
343          */
344         if (start < kernel_start)
345                 __create_pgd_mapping(pgd, start,
346                                      __phys_to_virt(start),
347                                      kernel_start - start, PAGE_KERNEL,
348                                      early_pgtable_alloc,
349                                      !debug_pagealloc_enabled());
350         if (kernel_end < end)
351                 __create_pgd_mapping(pgd, kernel_end,
352                                      __phys_to_virt(kernel_end),
353                                      end - kernel_end, PAGE_KERNEL,
354                                      early_pgtable_alloc,
355                                      !debug_pagealloc_enabled());
356 
357         /*
358          * Map the linear alias of the [_text, __init_begin) interval as
359          * read-only/non-executable. This makes the contents of the
360          * region accessible to subsystems such as hibernate, but
361          * protects it from inadvertent modification or execution.
362          */
363         __create_pgd_mapping(pgd, kernel_start, __phys_to_virt(kernel_start),
364                              kernel_end - kernel_start, PAGE_KERNEL_RO,
365                              early_pgtable_alloc, !debug_pagealloc_enabled());
366 }
367 
368 static void __init map_mem(pgd_t *pgd)
369 {
370         struct memblock_region *reg;
371 
372         /* map all the memory banks */
373         for_each_memblock(memory, reg) {
374                 phys_addr_t start = reg->base;
375                 phys_addr_t end = start + reg->size;
376 
377                 if (start >= end)
378                         break;
379                 if (memblock_is_nomap(reg))
380                         continue;
381 
382                 __map_memblock(pgd, start, end);
383         }
384 }
385 
386 void mark_rodata_ro(void)
387 {
388         unsigned long section_size;
389 
390         section_size = (unsigned long)_etext - (unsigned long)_text;
391         create_mapping_late(__pa(_text), (unsigned long)_text,
392                             section_size, PAGE_KERNEL_ROX);
393         /*
394          * mark .rodata as read only. Use __init_begin rather than __end_rodata
395          * to cover NOTES and EXCEPTION_TABLE.
396          */
397         section_size = (unsigned long)__init_begin - (unsigned long)__start_rodata;
398         create_mapping_late(__pa(__start_rodata), (unsigned long)__start_rodata,
399                             section_size, PAGE_KERNEL_RO);
400 }
401 
402 void fixup_init(void)
403 {
404         /*
405          * Unmap the __init region but leave the VM area in place. This
406          * prevents the region from being reused for kernel modules, which
407          * is not supported by kallsyms.
408          */
409         unmap_kernel_range((u64)__init_begin, (u64)(__init_end - __init_begin));
410 }
411 
412 static void __init map_kernel_segment(pgd_t *pgd, void *va_start, void *va_end,
413                                       pgprot_t prot, struct vm_struct *vma)
414 {
415         phys_addr_t pa_start = __pa(va_start);
416         unsigned long size = va_end - va_start;
417 
418         BUG_ON(!PAGE_ALIGNED(pa_start));
419         BUG_ON(!PAGE_ALIGNED(size));
420 
421         __create_pgd_mapping(pgd, pa_start, (unsigned long)va_start, size, prot,
422                              early_pgtable_alloc, !debug_pagealloc_enabled());
423 
424         vma->addr       = va_start;
425         vma->phys_addr  = pa_start;
426         vma->size       = size;
427         vma->flags      = VM_MAP;
428         vma->caller     = __builtin_return_address(0);
429 
430         vm_area_add_early(vma);
431 }
432 
433 /*
434  * Create fine-grained mappings for the kernel.
435  */
436 static void __init map_kernel(pgd_t *pgd)
437 {
438         static struct vm_struct vmlinux_text, vmlinux_rodata, vmlinux_init, vmlinux_data;
439 
440         map_kernel_segment(pgd, _text, _etext, PAGE_KERNEL_EXEC, &vmlinux_text);
441         map_kernel_segment(pgd, __start_rodata, __init_begin, PAGE_KERNEL, &vmlinux_rodata);
442         map_kernel_segment(pgd, __init_begin, __init_end, PAGE_KERNEL_EXEC,
443                            &vmlinux_init);
444         map_kernel_segment(pgd, _data, _end, PAGE_KERNEL, &vmlinux_data);
445 
446         if (!pgd_val(*pgd_offset_raw(pgd, FIXADDR_START))) {
447                 /*
448                  * The fixmap falls in a separate pgd to the kernel, and doesn't
449                  * live in the carveout for the swapper_pg_dir. We can simply
450                  * re-use the existing dir for the fixmap.
451                  */
452                 set_pgd(pgd_offset_raw(pgd, FIXADDR_START),
453                         *pgd_offset_k(FIXADDR_START));
454         } else if (CONFIG_PGTABLE_LEVELS > 3) {
455                 /*
456                  * The fixmap shares its top level pgd entry with the kernel
457                  * mapping. This can really only occur when we are running
458                  * with 16k/4 levels, so we can simply reuse the pud level
459                  * entry instead.
460                  */
461                 BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES));
462                 set_pud(pud_set_fixmap_offset(pgd, FIXADDR_START),
463                         __pud(__pa(bm_pmd) | PUD_TYPE_TABLE));
464                 pud_clear_fixmap();
465         } else {
466                 BUG();
467         }
468 
469         kasan_copy_shadow(pgd);
470 }
471 
472 /*
473  * paging_init() sets up the page tables, initialises the zone memory
474  * maps and sets up the zero page.
475  */
476 void __init paging_init(void)
477 {
478         phys_addr_t pgd_phys = early_pgtable_alloc();
479         pgd_t *pgd = pgd_set_fixmap(pgd_phys);
480 
481         map_kernel(pgd);
482         map_mem(pgd);
483 
484         /*
485          * We want to reuse the original swapper_pg_dir so we don't have to
486          * communicate the new address to non-coherent secondaries in
487          * secondary_entry, and so cpu_switch_mm can generate the address with
488          * adrp+add rather than a load from some global variable.
489          *
490          * To do this we need to go via a temporary pgd.
491          */
492         cpu_replace_ttbr1(__va(pgd_phys));
493         memcpy(swapper_pg_dir, pgd, PAGE_SIZE);
494         cpu_replace_ttbr1(swapper_pg_dir);
495 
496         pgd_clear_fixmap();
497         memblock_free(pgd_phys, PAGE_SIZE);
498 
499         /*
500          * We only reuse the PGD from the swapper_pg_dir, not the pud + pmd
501          * allocated with it.
502          */
503         memblock_free(__pa(swapper_pg_dir) + PAGE_SIZE,
504                       SWAPPER_DIR_SIZE - PAGE_SIZE);
505 }
506 
507 /*
508  * Check whether a kernel address is valid (derived from arch/x86/).
509  */
510 int kern_addr_valid(unsigned long addr)
511 {
512         pgd_t *pgd;
513         pud_t *pud;
514         pmd_t *pmd;
515         pte_t *pte;
516 
517         if ((((long)addr) >> VA_BITS) != -1UL)
518                 return 0;
519 
520         pgd = pgd_offset_k(addr);
521         if (pgd_none(*pgd))
522                 return 0;
523 
524         pud = pud_offset(pgd, addr);
525         if (pud_none(*pud))
526                 return 0;
527 
528         if (pud_sect(*pud))
529                 return pfn_valid(pud_pfn(*pud));
530 
531         pmd = pmd_offset(pud, addr);
532         if (pmd_none(*pmd))
533                 return 0;
534 
535         if (pmd_sect(*pmd))
536                 return pfn_valid(pmd_pfn(*pmd));
537 
538         pte = pte_offset_kernel(pmd, addr);
539         if (pte_none(*pte))
540                 return 0;
541 
542         return pfn_valid(pte_pfn(*pte));
543 }
544 #ifdef CONFIG_SPARSEMEM_VMEMMAP
545 #if !ARM64_SWAPPER_USES_SECTION_MAPS
546 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node)
547 {
548         return vmemmap_populate_basepages(start, end, node);
549 }
550 #else   /* !ARM64_SWAPPER_USES_SECTION_MAPS */
551 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node)
552 {
553         unsigned long addr = start;
554         unsigned long next;
555         pgd_t *pgd;
556         pud_t *pud;
557         pmd_t *pmd;
558 
559         do {
560                 next = pmd_addr_end(addr, end);
561 
562                 pgd = vmemmap_pgd_populate(addr, node);
563                 if (!pgd)
564                         return -ENOMEM;
565 
566                 pud = vmemmap_pud_populate(pgd, addr, node);
567                 if (!pud)
568                         return -ENOMEM;
569 
570                 pmd = pmd_offset(pud, addr);
571                 if (pmd_none(*pmd)) {
572                         void *p = NULL;
573 
574                         p = vmemmap_alloc_block_buf(PMD_SIZE, node);
575                         if (!p)
576                                 return -ENOMEM;
577 
578                         set_pmd(pmd, __pmd(__pa(p) | PROT_SECT_NORMAL));
579                 } else
580                         vmemmap_verify((pte_t *)pmd, node, addr, next);
581         } while (addr = next, addr != end);
582 
583         return 0;
584 }
585 #endif  /* CONFIG_ARM64_64K_PAGES */
586 void vmemmap_free(unsigned long start, unsigned long end)
587 {
588 }
589 #endif  /* CONFIG_SPARSEMEM_VMEMMAP */
590 
591 static inline pud_t * fixmap_pud(unsigned long addr)
592 {
593         pgd_t *pgd = pgd_offset_k(addr);
594 
595         BUG_ON(pgd_none(*pgd) || pgd_bad(*pgd));
596 
597         return pud_offset_kimg(pgd, addr);
598 }
599 
600 static inline pmd_t * fixmap_pmd(unsigned long addr)
601 {
602         pud_t *pud = fixmap_pud(addr);
603 
604         BUG_ON(pud_none(*pud) || pud_bad(*pud));
605 
606         return pmd_offset_kimg(pud, addr);
607 }
608 
609 static inline pte_t * fixmap_pte(unsigned long addr)
610 {
611         return &bm_pte[pte_index(addr)];
612 }
613 
614 void __init early_fixmap_init(void)
615 {
616         pgd_t *pgd;
617         pud_t *pud;
618         pmd_t *pmd;
619         unsigned long addr = FIXADDR_START;
620 
621         pgd = pgd_offset_k(addr);
622         if (CONFIG_PGTABLE_LEVELS > 3 &&
623             !(pgd_none(*pgd) || pgd_page_paddr(*pgd) == __pa(bm_pud))) {
624                 /*
625                  * We only end up here if the kernel mapping and the fixmap
626                  * share the top level pgd entry, which should only happen on
627                  * 16k/4 levels configurations.
628                  */
629                 BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES));
630                 pud = pud_offset_kimg(pgd, addr);
631         } else {
632                 pgd_populate(&init_mm, pgd, bm_pud);
633                 pud = fixmap_pud(addr);
634         }
635         pud_populate(&init_mm, pud, bm_pmd);
636         pmd = fixmap_pmd(addr);
637         pmd_populate_kernel(&init_mm, pmd, bm_pte);
638 
639         /*
640          * The boot-ioremap range spans multiple pmds, for which
641          * we are not prepared:
642          */
643         BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT)
644                      != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT));
645 
646         if ((pmd != fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)))
647              || pmd != fixmap_pmd(fix_to_virt(FIX_BTMAP_END))) {
648                 WARN_ON(1);
649                 pr_warn("pmd %p != %p, %p\n",
650                         pmd, fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)),
651                         fixmap_pmd(fix_to_virt(FIX_BTMAP_END)));
652                 pr_warn("fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n",
653                         fix_to_virt(FIX_BTMAP_BEGIN));
654                 pr_warn("fix_to_virt(FIX_BTMAP_END):   %08lx\n",
655                         fix_to_virt(FIX_BTMAP_END));
656 
657                 pr_warn("FIX_BTMAP_END:       %d\n", FIX_BTMAP_END);
658                 pr_warn("FIX_BTMAP_BEGIN:     %d\n", FIX_BTMAP_BEGIN);
659         }
660 }
661 
662 void __set_fixmap(enum fixed_addresses idx,
663                                phys_addr_t phys, pgprot_t flags)
664 {
665         unsigned long addr = __fix_to_virt(idx);
666         pte_t *pte;
667 
668         BUG_ON(idx <= FIX_HOLE || idx >= __end_of_fixed_addresses);
669 
670         pte = fixmap_pte(addr);
671 
672         if (pgprot_val(flags)) {
673                 set_pte(pte, pfn_pte(phys >> PAGE_SHIFT, flags));
674         } else {
675                 pte_clear(&init_mm, addr, pte);
676                 flush_tlb_kernel_range(addr, addr+PAGE_SIZE);
677         }
678 }
679 
680 void *__init __fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot)
681 {
682         const u64 dt_virt_base = __fix_to_virt(FIX_FDT);
683         int offset;
684         void *dt_virt;
685 
686         /*
687          * Check whether the physical FDT address is set and meets the minimum
688          * alignment requirement. Since we are relying on MIN_FDT_ALIGN to be
689          * at least 8 bytes so that we can always access the magic and size
690          * fields of the FDT header after mapping the first chunk, double check
691          * here if that is indeed the case.
692          */
693         BUILD_BUG_ON(MIN_FDT_ALIGN < 8);
694         if (!dt_phys || dt_phys % MIN_FDT_ALIGN)
695                 return NULL;
696 
697         /*
698          * Make sure that the FDT region can be mapped without the need to
699          * allocate additional translation table pages, so that it is safe
700          * to call create_mapping_noalloc() this early.
701          *
702          * On 64k pages, the FDT will be mapped using PTEs, so we need to
703          * be in the same PMD as the rest of the fixmap.
704          * On 4k pages, we'll use section mappings for the FDT so we only
705          * have to be in the same PUD.
706          */
707         BUILD_BUG_ON(dt_virt_base % SZ_2M);
708 
709         BUILD_BUG_ON(__fix_to_virt(FIX_FDT_END) >> SWAPPER_TABLE_SHIFT !=
710                      __fix_to_virt(FIX_BTMAP_BEGIN) >> SWAPPER_TABLE_SHIFT);
711 
712         offset = dt_phys % SWAPPER_BLOCK_SIZE;
713         dt_virt = (void *)dt_virt_base + offset;
714 
715         /* map the first chunk so we can read the size from the header */
716         create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE),
717                         dt_virt_base, SWAPPER_BLOCK_SIZE, prot);
718 
719         if (fdt_magic(dt_virt) != FDT_MAGIC)
720                 return NULL;
721 
722         *size = fdt_totalsize(dt_virt);
723         if (*size > MAX_FDT_SIZE)
724                 return NULL;
725 
726         if (offset + *size > SWAPPER_BLOCK_SIZE)
727                 create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE), dt_virt_base,
728                                round_up(offset + *size, SWAPPER_BLOCK_SIZE), prot);
729 
730         return dt_virt;
731 }
732 
733 void *__init fixmap_remap_fdt(phys_addr_t dt_phys)
734 {
735         void *dt_virt;
736         int size;
737 
738         dt_virt = __fixmap_remap_fdt(dt_phys, &size, PAGE_KERNEL_RO);
739         if (!dt_virt)
740                 return NULL;
741 
742         memblock_reserve(dt_phys, size);
743         return dt_virt;
744 }
745 
746 int __init arch_ioremap_pud_supported(void)
747 {
748         /* only 4k granule supports level 1 block mappings */
749         return IS_ENABLED(CONFIG_ARM64_4K_PAGES);
750 }
751 
752 int __init arch_ioremap_pmd_supported(void)
753 {
754         return 1;
755 }
756 
757 int pud_set_huge(pud_t *pud, phys_addr_t phys, pgprot_t prot)
758 {
759         BUG_ON(phys & ~PUD_MASK);
760         set_pud(pud, __pud(phys | PUD_TYPE_SECT | pgprot_val(mk_sect_prot(prot))));
761         return 1;
762 }
763 
764 int pmd_set_huge(pmd_t *pmd, phys_addr_t phys, pgprot_t prot)
765 {
766         BUG_ON(phys & ~PMD_MASK);
767         set_pmd(pmd, __pmd(phys | PMD_TYPE_SECT | pgprot_val(mk_sect_prot(prot))));
768         return 1;
769 }
770 
771 int pud_clear_huge(pud_t *pud)
772 {
773         if (!pud_sect(*pud))
774                 return 0;
775         pud_clear(pud);
776         return 1;
777 }
778 
779 int pmd_clear_huge(pmd_t *pmd)
780 {
781         if (!pmd_sect(*pmd))
782                 return 0;
783         pmd_clear(pmd);
784         return 1;
785 }
786 

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