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Linux/arch/arm64/mm/mmu.c

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  1 // SPDX-License-Identifier: GPL-2.0-only
  2 /*
  3  * Based on arch/arm/mm/mmu.c
  4  *
  5  * Copyright (C) 1995-2005 Russell King
  6  * Copyright (C) 2012 ARM Ltd.
  7  */
  8 
  9 #include <linux/cache.h>
 10 #include <linux/export.h>
 11 #include <linux/kernel.h>
 12 #include <linux/errno.h>
 13 #include <linux/init.h>
 14 #include <linux/ioport.h>
 15 #include <linux/kexec.h>
 16 #include <linux/libfdt.h>
 17 #include <linux/mman.h>
 18 #include <linux/nodemask.h>
 19 #include <linux/memblock.h>
 20 #include <linux/fs.h>
 21 #include <linux/io.h>
 22 #include <linux/mm.h>
 23 #include <linux/vmalloc.h>
 24 
 25 #include <asm/barrier.h>
 26 #include <asm/cputype.h>
 27 #include <asm/fixmap.h>
 28 #include <asm/kasan.h>
 29 #include <asm/kernel-pgtable.h>
 30 #include <asm/sections.h>
 31 #include <asm/setup.h>
 32 #include <linux/sizes.h>
 33 #include <asm/tlb.h>
 34 #include <asm/mmu_context.h>
 35 #include <asm/ptdump.h>
 36 #include <asm/tlbflush.h>
 37 
 38 #define NO_BLOCK_MAPPINGS       BIT(0)
 39 #define NO_CONT_MAPPINGS        BIT(1)
 40 
 41 u64 idmap_t0sz = TCR_T0SZ(VA_BITS);
 42 u64 idmap_ptrs_per_pgd = PTRS_PER_PGD;
 43 u64 vabits_user __ro_after_init;
 44 EXPORT_SYMBOL(vabits_user);
 45 
 46 u64 kimage_voffset __ro_after_init;
 47 EXPORT_SYMBOL(kimage_voffset);
 48 
 49 /*
 50  * Empty_zero_page is a special page that is used for zero-initialized data
 51  * and COW.
 52  */
 53 unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] __page_aligned_bss;
 54 EXPORT_SYMBOL(empty_zero_page);
 55 
 56 static pte_t bm_pte[PTRS_PER_PTE] __page_aligned_bss;
 57 static pmd_t bm_pmd[PTRS_PER_PMD] __page_aligned_bss __maybe_unused;
 58 static pud_t bm_pud[PTRS_PER_PUD] __page_aligned_bss __maybe_unused;
 59 
 60 static DEFINE_SPINLOCK(swapper_pgdir_lock);
 61 
 62 void set_swapper_pgd(pgd_t *pgdp, pgd_t pgd)
 63 {
 64         pgd_t *fixmap_pgdp;
 65 
 66         spin_lock(&swapper_pgdir_lock);
 67         fixmap_pgdp = pgd_set_fixmap(__pa_symbol(pgdp));
 68         WRITE_ONCE(*fixmap_pgdp, pgd);
 69         /*
 70          * We need dsb(ishst) here to ensure the page-table-walker sees
 71          * our new entry before set_p?d() returns. The fixmap's
 72          * flush_tlb_kernel_range() via clear_fixmap() does this for us.
 73          */
 74         pgd_clear_fixmap();
 75         spin_unlock(&swapper_pgdir_lock);
 76 }
 77 
 78 pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
 79                               unsigned long size, pgprot_t vma_prot)
 80 {
 81         if (!pfn_valid(pfn))
 82                 return pgprot_noncached(vma_prot);
 83         else if (file->f_flags & O_SYNC)
 84                 return pgprot_writecombine(vma_prot);
 85         return vma_prot;
 86 }
 87 EXPORT_SYMBOL(phys_mem_access_prot);
 88 
 89 static phys_addr_t __init early_pgtable_alloc(int shift)
 90 {
 91         phys_addr_t phys;
 92         void *ptr;
 93 
 94         phys = memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE);
 95         if (!phys)
 96                 panic("Failed to allocate page table page\n");
 97 
 98         /*
 99          * The FIX_{PGD,PUD,PMD} slots may be in active use, but the FIX_PTE
100          * slot will be free, so we can (ab)use the FIX_PTE slot to initialise
101          * any level of table.
102          */
103         ptr = pte_set_fixmap(phys);
104 
105         memset(ptr, 0, PAGE_SIZE);
106 
107         /*
108          * Implicit barriers also ensure the zeroed page is visible to the page
109          * table walker
110          */
111         pte_clear_fixmap();
112 
113         return phys;
114 }
115 
116 static bool pgattr_change_is_safe(u64 old, u64 new)
117 {
118         /*
119          * The following mapping attributes may be updated in live
120          * kernel mappings without the need for break-before-make.
121          */
122         static const pteval_t mask = PTE_PXN | PTE_RDONLY | PTE_WRITE | PTE_NG;
123 
124         /* creating or taking down mappings is always safe */
125         if (old == 0 || new == 0)
126                 return true;
127 
128         /* live contiguous mappings may not be manipulated at all */
129         if ((old | new) & PTE_CONT)
130                 return false;
131 
132         /* Transitioning from Non-Global to Global is unsafe */
133         if (old & ~new & PTE_NG)
134                 return false;
135 
136         return ((old ^ new) & ~mask) == 0;
137 }
138 
139 static void init_pte(pmd_t *pmdp, unsigned long addr, unsigned long end,
140                      phys_addr_t phys, pgprot_t prot)
141 {
142         pte_t *ptep;
143 
144         ptep = pte_set_fixmap_offset(pmdp, addr);
145         do {
146                 pte_t old_pte = READ_ONCE(*ptep);
147 
148                 set_pte(ptep, pfn_pte(__phys_to_pfn(phys), prot));
149 
150                 /*
151                  * After the PTE entry has been populated once, we
152                  * only allow updates to the permission attributes.
153                  */
154                 BUG_ON(!pgattr_change_is_safe(pte_val(old_pte),
155                                               READ_ONCE(pte_val(*ptep))));
156 
157                 phys += PAGE_SIZE;
158         } while (ptep++, addr += PAGE_SIZE, addr != end);
159 
160         pte_clear_fixmap();
161 }
162 
163 static void alloc_init_cont_pte(pmd_t *pmdp, unsigned long addr,
164                                 unsigned long end, phys_addr_t phys,
165                                 pgprot_t prot,
166                                 phys_addr_t (*pgtable_alloc)(int),
167                                 int flags)
168 {
169         unsigned long next;
170         pmd_t pmd = READ_ONCE(*pmdp);
171 
172         BUG_ON(pmd_sect(pmd));
173         if (pmd_none(pmd)) {
174                 phys_addr_t pte_phys;
175                 BUG_ON(!pgtable_alloc);
176                 pte_phys = pgtable_alloc(PAGE_SHIFT);
177                 __pmd_populate(pmdp, pte_phys, PMD_TYPE_TABLE);
178                 pmd = READ_ONCE(*pmdp);
179         }
180         BUG_ON(pmd_bad(pmd));
181 
182         do {
183                 pgprot_t __prot = prot;
184 
185                 next = pte_cont_addr_end(addr, end);
186 
187                 /* use a contiguous mapping if the range is suitably aligned */
188                 if ((((addr | next | phys) & ~CONT_PTE_MASK) == 0) &&
189                     (flags & NO_CONT_MAPPINGS) == 0)
190                         __prot = __pgprot(pgprot_val(prot) | PTE_CONT);
191 
192                 init_pte(pmdp, addr, next, phys, __prot);
193 
194                 phys += next - addr;
195         } while (addr = next, addr != end);
196 }
197 
198 static void init_pmd(pud_t *pudp, unsigned long addr, unsigned long end,
199                      phys_addr_t phys, pgprot_t prot,
200                      phys_addr_t (*pgtable_alloc)(int), int flags)
201 {
202         unsigned long next;
203         pmd_t *pmdp;
204 
205         pmdp = pmd_set_fixmap_offset(pudp, addr);
206         do {
207                 pmd_t old_pmd = READ_ONCE(*pmdp);
208 
209                 next = pmd_addr_end(addr, end);
210 
211                 /* try section mapping first */
212                 if (((addr | next | phys) & ~SECTION_MASK) == 0 &&
213                     (flags & NO_BLOCK_MAPPINGS) == 0) {
214                         pmd_set_huge(pmdp, phys, prot);
215 
216                         /*
217                          * After the PMD entry has been populated once, we
218                          * only allow updates to the permission attributes.
219                          */
220                         BUG_ON(!pgattr_change_is_safe(pmd_val(old_pmd),
221                                                       READ_ONCE(pmd_val(*pmdp))));
222                 } else {
223                         alloc_init_cont_pte(pmdp, addr, next, phys, prot,
224                                             pgtable_alloc, flags);
225 
226                         BUG_ON(pmd_val(old_pmd) != 0 &&
227                                pmd_val(old_pmd) != READ_ONCE(pmd_val(*pmdp)));
228                 }
229                 phys += next - addr;
230         } while (pmdp++, addr = next, addr != end);
231 
232         pmd_clear_fixmap();
233 }
234 
235 static void alloc_init_cont_pmd(pud_t *pudp, unsigned long addr,
236                                 unsigned long end, phys_addr_t phys,
237                                 pgprot_t prot,
238                                 phys_addr_t (*pgtable_alloc)(int), int flags)
239 {
240         unsigned long next;
241         pud_t pud = READ_ONCE(*pudp);
242 
243         /*
244          * Check for initial section mappings in the pgd/pud.
245          */
246         BUG_ON(pud_sect(pud));
247         if (pud_none(pud)) {
248                 phys_addr_t pmd_phys;
249                 BUG_ON(!pgtable_alloc);
250                 pmd_phys = pgtable_alloc(PMD_SHIFT);
251                 __pud_populate(pudp, pmd_phys, PUD_TYPE_TABLE);
252                 pud = READ_ONCE(*pudp);
253         }
254         BUG_ON(pud_bad(pud));
255 
256         do {
257                 pgprot_t __prot = prot;
258 
259                 next = pmd_cont_addr_end(addr, end);
260 
261                 /* use a contiguous mapping if the range is suitably aligned */
262                 if ((((addr | next | phys) & ~CONT_PMD_MASK) == 0) &&
263                     (flags & NO_CONT_MAPPINGS) == 0)
264                         __prot = __pgprot(pgprot_val(prot) | PTE_CONT);
265 
266                 init_pmd(pudp, addr, next, phys, __prot, pgtable_alloc, flags);
267 
268                 phys += next - addr;
269         } while (addr = next, addr != end);
270 }
271 
272 static inline bool use_1G_block(unsigned long addr, unsigned long next,
273                         unsigned long phys)
274 {
275         if (PAGE_SHIFT != 12)
276                 return false;
277 
278         if (((addr | next | phys) & ~PUD_MASK) != 0)
279                 return false;
280 
281         return true;
282 }
283 
284 static void alloc_init_pud(pgd_t *pgdp, unsigned long addr, unsigned long end,
285                            phys_addr_t phys, pgprot_t prot,
286                            phys_addr_t (*pgtable_alloc)(int),
287                            int flags)
288 {
289         unsigned long next;
290         pud_t *pudp;
291         pgd_t pgd = READ_ONCE(*pgdp);
292 
293         if (pgd_none(pgd)) {
294                 phys_addr_t pud_phys;
295                 BUG_ON(!pgtable_alloc);
296                 pud_phys = pgtable_alloc(PUD_SHIFT);
297                 __pgd_populate(pgdp, pud_phys, PUD_TYPE_TABLE);
298                 pgd = READ_ONCE(*pgdp);
299         }
300         BUG_ON(pgd_bad(pgd));
301 
302         pudp = pud_set_fixmap_offset(pgdp, addr);
303         do {
304                 pud_t old_pud = READ_ONCE(*pudp);
305 
306                 next = pud_addr_end(addr, end);
307 
308                 /*
309                  * For 4K granule only, attempt to put down a 1GB block
310                  */
311                 if (use_1G_block(addr, next, phys) &&
312                     (flags & NO_BLOCK_MAPPINGS) == 0) {
313                         pud_set_huge(pudp, phys, prot);
314 
315                         /*
316                          * After the PUD entry has been populated once, we
317                          * only allow updates to the permission attributes.
318                          */
319                         BUG_ON(!pgattr_change_is_safe(pud_val(old_pud),
320                                                       READ_ONCE(pud_val(*pudp))));
321                 } else {
322                         alloc_init_cont_pmd(pudp, addr, next, phys, prot,
323                                             pgtable_alloc, flags);
324 
325                         BUG_ON(pud_val(old_pud) != 0 &&
326                                pud_val(old_pud) != READ_ONCE(pud_val(*pudp)));
327                 }
328                 phys += next - addr;
329         } while (pudp++, addr = next, addr != end);
330 
331         pud_clear_fixmap();
332 }
333 
334 static void __create_pgd_mapping(pgd_t *pgdir, phys_addr_t phys,
335                                  unsigned long virt, phys_addr_t size,
336                                  pgprot_t prot,
337                                  phys_addr_t (*pgtable_alloc)(int),
338                                  int flags)
339 {
340         unsigned long addr, length, end, next;
341         pgd_t *pgdp = pgd_offset_raw(pgdir, virt);
342 
343         /*
344          * If the virtual and physical address don't have the same offset
345          * within a page, we cannot map the region as the caller expects.
346          */
347         if (WARN_ON((phys ^ virt) & ~PAGE_MASK))
348                 return;
349 
350         phys &= PAGE_MASK;
351         addr = virt & PAGE_MASK;
352         length = PAGE_ALIGN(size + (virt & ~PAGE_MASK));
353 
354         end = addr + length;
355         do {
356                 next = pgd_addr_end(addr, end);
357                 alloc_init_pud(pgdp, addr, next, phys, prot, pgtable_alloc,
358                                flags);
359                 phys += next - addr;
360         } while (pgdp++, addr = next, addr != end);
361 }
362 
363 static phys_addr_t __pgd_pgtable_alloc(int shift)
364 {
365         void *ptr = (void *)__get_free_page(GFP_PGTABLE_KERNEL);
366         BUG_ON(!ptr);
367 
368         /* Ensure the zeroed page is visible to the page table walker */
369         dsb(ishst);
370         return __pa(ptr);
371 }
372 
373 static phys_addr_t pgd_pgtable_alloc(int shift)
374 {
375         phys_addr_t pa = __pgd_pgtable_alloc(shift);
376 
377         /*
378          * Call proper page table ctor in case later we need to
379          * call core mm functions like apply_to_page_range() on
380          * this pre-allocated page table.
381          *
382          * We don't select ARCH_ENABLE_SPLIT_PMD_PTLOCK if pmd is
383          * folded, and if so pgtable_pmd_page_ctor() becomes nop.
384          */
385         if (shift == PAGE_SHIFT)
386                 BUG_ON(!pgtable_page_ctor(phys_to_page(pa)));
387         else if (shift == PMD_SHIFT)
388                 BUG_ON(!pgtable_pmd_page_ctor(phys_to_page(pa)));
389 
390         return pa;
391 }
392 
393 /*
394  * This function can only be used to modify existing table entries,
395  * without allocating new levels of table. Note that this permits the
396  * creation of new section or page entries.
397  */
398 static void __init create_mapping_noalloc(phys_addr_t phys, unsigned long virt,
399                                   phys_addr_t size, pgprot_t prot)
400 {
401         if (virt < VMALLOC_START) {
402                 pr_warn("BUG: not creating mapping for %pa at 0x%016lx - outside kernel range\n",
403                         &phys, virt);
404                 return;
405         }
406         __create_pgd_mapping(init_mm.pgd, phys, virt, size, prot, NULL,
407                              NO_CONT_MAPPINGS);
408 }
409 
410 void __init create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys,
411                                unsigned long virt, phys_addr_t size,
412                                pgprot_t prot, bool page_mappings_only)
413 {
414         int flags = 0;
415 
416         BUG_ON(mm == &init_mm);
417 
418         if (page_mappings_only)
419                 flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;
420 
421         __create_pgd_mapping(mm->pgd, phys, virt, size, prot,
422                              pgd_pgtable_alloc, flags);
423 }
424 
425 static void update_mapping_prot(phys_addr_t phys, unsigned long virt,
426                                 phys_addr_t size, pgprot_t prot)
427 {
428         if (virt < VMALLOC_START) {
429                 pr_warn("BUG: not updating mapping for %pa at 0x%016lx - outside kernel range\n",
430                         &phys, virt);
431                 return;
432         }
433 
434         __create_pgd_mapping(init_mm.pgd, phys, virt, size, prot, NULL,
435                              NO_CONT_MAPPINGS);
436 
437         /* flush the TLBs after updating live kernel mappings */
438         flush_tlb_kernel_range(virt, virt + size);
439 }
440 
441 static void __init __map_memblock(pgd_t *pgdp, phys_addr_t start,
442                                   phys_addr_t end, pgprot_t prot, int flags)
443 {
444         __create_pgd_mapping(pgdp, start, __phys_to_virt(start), end - start,
445                              prot, early_pgtable_alloc, flags);
446 }
447 
448 void __init mark_linear_text_alias_ro(void)
449 {
450         /*
451          * Remove the write permissions from the linear alias of .text/.rodata
452          */
453         update_mapping_prot(__pa_symbol(_text), (unsigned long)lm_alias(_text),
454                             (unsigned long)__init_begin - (unsigned long)_text,
455                             PAGE_KERNEL_RO);
456 }
457 
458 static void __init map_mem(pgd_t *pgdp)
459 {
460         phys_addr_t kernel_start = __pa_symbol(_text);
461         phys_addr_t kernel_end = __pa_symbol(__init_begin);
462         struct memblock_region *reg;
463         int flags = 0;
464 
465         if (rodata_full || debug_pagealloc_enabled())
466                 flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;
467 
468         /*
469          * Take care not to create a writable alias for the
470          * read-only text and rodata sections of the kernel image.
471          * So temporarily mark them as NOMAP to skip mappings in
472          * the following for-loop
473          */
474         memblock_mark_nomap(kernel_start, kernel_end - kernel_start);
475 #ifdef CONFIG_KEXEC_CORE
476         if (crashk_res.end)
477                 memblock_mark_nomap(crashk_res.start,
478                                     resource_size(&crashk_res));
479 #endif
480 
481         /* map all the memory banks */
482         for_each_memblock(memory, reg) {
483                 phys_addr_t start = reg->base;
484                 phys_addr_t end = start + reg->size;
485 
486                 if (start >= end)
487                         break;
488                 if (memblock_is_nomap(reg))
489                         continue;
490 
491                 __map_memblock(pgdp, start, end, PAGE_KERNEL, flags);
492         }
493 
494         /*
495          * Map the linear alias of the [_text, __init_begin) interval
496          * as non-executable now, and remove the write permission in
497          * mark_linear_text_alias_ro() below (which will be called after
498          * alternative patching has completed). This makes the contents
499          * of the region accessible to subsystems such as hibernate,
500          * but protects it from inadvertent modification or execution.
501          * Note that contiguous mappings cannot be remapped in this way,
502          * so we should avoid them here.
503          */
504         __map_memblock(pgdp, kernel_start, kernel_end,
505                        PAGE_KERNEL, NO_CONT_MAPPINGS);
506         memblock_clear_nomap(kernel_start, kernel_end - kernel_start);
507 
508 #ifdef CONFIG_KEXEC_CORE
509         /*
510          * Use page-level mappings here so that we can shrink the region
511          * in page granularity and put back unused memory to buddy system
512          * through /sys/kernel/kexec_crash_size interface.
513          */
514         if (crashk_res.end) {
515                 __map_memblock(pgdp, crashk_res.start, crashk_res.end + 1,
516                                PAGE_KERNEL,
517                                NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS);
518                 memblock_clear_nomap(crashk_res.start,
519                                      resource_size(&crashk_res));
520         }
521 #endif
522 }
523 
524 void mark_rodata_ro(void)
525 {
526         unsigned long section_size;
527 
528         /*
529          * mark .rodata as read only. Use __init_begin rather than __end_rodata
530          * to cover NOTES and EXCEPTION_TABLE.
531          */
532         section_size = (unsigned long)__init_begin - (unsigned long)__start_rodata;
533         update_mapping_prot(__pa_symbol(__start_rodata), (unsigned long)__start_rodata,
534                             section_size, PAGE_KERNEL_RO);
535 
536         debug_checkwx();
537 }
538 
539 static void __init map_kernel_segment(pgd_t *pgdp, void *va_start, void *va_end,
540                                       pgprot_t prot, struct vm_struct *vma,
541                                       int flags, unsigned long vm_flags)
542 {
543         phys_addr_t pa_start = __pa_symbol(va_start);
544         unsigned long size = va_end - va_start;
545 
546         BUG_ON(!PAGE_ALIGNED(pa_start));
547         BUG_ON(!PAGE_ALIGNED(size));
548 
549         __create_pgd_mapping(pgdp, pa_start, (unsigned long)va_start, size, prot,
550                              early_pgtable_alloc, flags);
551 
552         if (!(vm_flags & VM_NO_GUARD))
553                 size += PAGE_SIZE;
554 
555         vma->addr       = va_start;
556         vma->phys_addr  = pa_start;
557         vma->size       = size;
558         vma->flags      = VM_MAP | vm_flags;
559         vma->caller     = __builtin_return_address(0);
560 
561         vm_area_add_early(vma);
562 }
563 
564 static int __init parse_rodata(char *arg)
565 {
566         int ret = strtobool(arg, &rodata_enabled);
567         if (!ret) {
568                 rodata_full = false;
569                 return 0;
570         }
571 
572         /* permit 'full' in addition to boolean options */
573         if (strcmp(arg, "full"))
574                 return -EINVAL;
575 
576         rodata_enabled = true;
577         rodata_full = true;
578         return 0;
579 }
580 early_param("rodata", parse_rodata);
581 
582 #ifdef CONFIG_UNMAP_KERNEL_AT_EL0
583 static int __init map_entry_trampoline(void)
584 {
585         pgprot_t prot = rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC;
586         phys_addr_t pa_start = __pa_symbol(__entry_tramp_text_start);
587 
588         /* The trampoline is always mapped and can therefore be global */
589         pgprot_val(prot) &= ~PTE_NG;
590 
591         /* Map only the text into the trampoline page table */
592         memset(tramp_pg_dir, 0, PGD_SIZE);
593         __create_pgd_mapping(tramp_pg_dir, pa_start, TRAMP_VALIAS, PAGE_SIZE,
594                              prot, __pgd_pgtable_alloc, 0);
595 
596         /* Map both the text and data into the kernel page table */
597         __set_fixmap(FIX_ENTRY_TRAMP_TEXT, pa_start, prot);
598         if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) {
599                 extern char __entry_tramp_data_start[];
600 
601                 __set_fixmap(FIX_ENTRY_TRAMP_DATA,
602                              __pa_symbol(__entry_tramp_data_start),
603                              PAGE_KERNEL_RO);
604         }
605 
606         return 0;
607 }
608 core_initcall(map_entry_trampoline);
609 #endif
610 
611 /*
612  * Create fine-grained mappings for the kernel.
613  */
614 static void __init map_kernel(pgd_t *pgdp)
615 {
616         static struct vm_struct vmlinux_text, vmlinux_rodata, vmlinux_inittext,
617                                 vmlinux_initdata, vmlinux_data;
618 
619         /*
620          * External debuggers may need to write directly to the text
621          * mapping to install SW breakpoints. Allow this (only) when
622          * explicitly requested with rodata=off.
623          */
624         pgprot_t text_prot = rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC;
625 
626         /*
627          * Only rodata will be remapped with different permissions later on,
628          * all other segments are allowed to use contiguous mappings.
629          */
630         map_kernel_segment(pgdp, _text, _etext, text_prot, &vmlinux_text, 0,
631                            VM_NO_GUARD);
632         map_kernel_segment(pgdp, __start_rodata, __inittext_begin, PAGE_KERNEL,
633                            &vmlinux_rodata, NO_CONT_MAPPINGS, VM_NO_GUARD);
634         map_kernel_segment(pgdp, __inittext_begin, __inittext_end, text_prot,
635                            &vmlinux_inittext, 0, VM_NO_GUARD);
636         map_kernel_segment(pgdp, __initdata_begin, __initdata_end, PAGE_KERNEL,
637                            &vmlinux_initdata, 0, VM_NO_GUARD);
638         map_kernel_segment(pgdp, _data, _end, PAGE_KERNEL, &vmlinux_data, 0, 0);
639 
640         if (!READ_ONCE(pgd_val(*pgd_offset_raw(pgdp, FIXADDR_START)))) {
641                 /*
642                  * The fixmap falls in a separate pgd to the kernel, and doesn't
643                  * live in the carveout for the swapper_pg_dir. We can simply
644                  * re-use the existing dir for the fixmap.
645                  */
646                 set_pgd(pgd_offset_raw(pgdp, FIXADDR_START),
647                         READ_ONCE(*pgd_offset_k(FIXADDR_START)));
648         } else if (CONFIG_PGTABLE_LEVELS > 3) {
649                 /*
650                  * The fixmap shares its top level pgd entry with the kernel
651                  * mapping. This can really only occur when we are running
652                  * with 16k/4 levels, so we can simply reuse the pud level
653                  * entry instead.
654                  */
655                 BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES));
656                 pud_populate(&init_mm,
657                              pud_set_fixmap_offset(pgdp, FIXADDR_START),
658                              lm_alias(bm_pmd));
659                 pud_clear_fixmap();
660         } else {
661                 BUG();
662         }
663 
664         kasan_copy_shadow(pgdp);
665 }
666 
667 void __init paging_init(void)
668 {
669         pgd_t *pgdp = pgd_set_fixmap(__pa_symbol(swapper_pg_dir));
670 
671         map_kernel(pgdp);
672         map_mem(pgdp);
673 
674         pgd_clear_fixmap();
675 
676         cpu_replace_ttbr1(lm_alias(swapper_pg_dir));
677         init_mm.pgd = swapper_pg_dir;
678 
679         memblock_free(__pa_symbol(init_pg_dir),
680                       __pa_symbol(init_pg_end) - __pa_symbol(init_pg_dir));
681 
682         memblock_allow_resize();
683 }
684 
685 /*
686  * Check whether a kernel address is valid (derived from arch/x86/).
687  */
688 int kern_addr_valid(unsigned long addr)
689 {
690         pgd_t *pgdp;
691         pud_t *pudp, pud;
692         pmd_t *pmdp, pmd;
693         pte_t *ptep, pte;
694 
695         if ((((long)addr) >> VA_BITS) != -1UL)
696                 return 0;
697 
698         pgdp = pgd_offset_k(addr);
699         if (pgd_none(READ_ONCE(*pgdp)))
700                 return 0;
701 
702         pudp = pud_offset(pgdp, addr);
703         pud = READ_ONCE(*pudp);
704         if (pud_none(pud))
705                 return 0;
706 
707         if (pud_sect(pud))
708                 return pfn_valid(pud_pfn(pud));
709 
710         pmdp = pmd_offset(pudp, addr);
711         pmd = READ_ONCE(*pmdp);
712         if (pmd_none(pmd))
713                 return 0;
714 
715         if (pmd_sect(pmd))
716                 return pfn_valid(pmd_pfn(pmd));
717 
718         ptep = pte_offset_kernel(pmdp, addr);
719         pte = READ_ONCE(*ptep);
720         if (pte_none(pte))
721                 return 0;
722 
723         return pfn_valid(pte_pfn(pte));
724 }
725 #ifdef CONFIG_SPARSEMEM_VMEMMAP
726 #if !ARM64_SWAPPER_USES_SECTION_MAPS
727 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
728                 struct vmem_altmap *altmap)
729 {
730         return vmemmap_populate_basepages(start, end, node);
731 }
732 #else   /* !ARM64_SWAPPER_USES_SECTION_MAPS */
733 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
734                 struct vmem_altmap *altmap)
735 {
736         unsigned long addr = start;
737         unsigned long next;
738         pgd_t *pgdp;
739         pud_t *pudp;
740         pmd_t *pmdp;
741 
742         do {
743                 next = pmd_addr_end(addr, end);
744 
745                 pgdp = vmemmap_pgd_populate(addr, node);
746                 if (!pgdp)
747                         return -ENOMEM;
748 
749                 pudp = vmemmap_pud_populate(pgdp, addr, node);
750                 if (!pudp)
751                         return -ENOMEM;
752 
753                 pmdp = pmd_offset(pudp, addr);
754                 if (pmd_none(READ_ONCE(*pmdp))) {
755                         void *p = NULL;
756 
757                         p = vmemmap_alloc_block_buf(PMD_SIZE, node);
758                         if (!p)
759                                 return -ENOMEM;
760 
761                         pmd_set_huge(pmdp, __pa(p), __pgprot(PROT_SECT_NORMAL));
762                 } else
763                         vmemmap_verify((pte_t *)pmdp, node, addr, next);
764         } while (addr = next, addr != end);
765 
766         return 0;
767 }
768 #endif  /* !ARM64_SWAPPER_USES_SECTION_MAPS */
769 void vmemmap_free(unsigned long start, unsigned long end,
770                 struct vmem_altmap *altmap)
771 {
772 }
773 #endif  /* CONFIG_SPARSEMEM_VMEMMAP */
774 
775 static inline pud_t * fixmap_pud(unsigned long addr)
776 {
777         pgd_t *pgdp = pgd_offset_k(addr);
778         pgd_t pgd = READ_ONCE(*pgdp);
779 
780         BUG_ON(pgd_none(pgd) || pgd_bad(pgd));
781 
782         return pud_offset_kimg(pgdp, addr);
783 }
784 
785 static inline pmd_t * fixmap_pmd(unsigned long addr)
786 {
787         pud_t *pudp = fixmap_pud(addr);
788         pud_t pud = READ_ONCE(*pudp);
789 
790         BUG_ON(pud_none(pud) || pud_bad(pud));
791 
792         return pmd_offset_kimg(pudp, addr);
793 }
794 
795 static inline pte_t * fixmap_pte(unsigned long addr)
796 {
797         return &bm_pte[pte_index(addr)];
798 }
799 
800 /*
801  * The p*d_populate functions call virt_to_phys implicitly so they can't be used
802  * directly on kernel symbols (bm_p*d). This function is called too early to use
803  * lm_alias so __p*d_populate functions must be used to populate with the
804  * physical address from __pa_symbol.
805  */
806 void __init early_fixmap_init(void)
807 {
808         pgd_t *pgdp, pgd;
809         pud_t *pudp;
810         pmd_t *pmdp;
811         unsigned long addr = FIXADDR_START;
812 
813         pgdp = pgd_offset_k(addr);
814         pgd = READ_ONCE(*pgdp);
815         if (CONFIG_PGTABLE_LEVELS > 3 &&
816             !(pgd_none(pgd) || pgd_page_paddr(pgd) == __pa_symbol(bm_pud))) {
817                 /*
818                  * We only end up here if the kernel mapping and the fixmap
819                  * share the top level pgd entry, which should only happen on
820                  * 16k/4 levels configurations.
821                  */
822                 BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES));
823                 pudp = pud_offset_kimg(pgdp, addr);
824         } else {
825                 if (pgd_none(pgd))
826                         __pgd_populate(pgdp, __pa_symbol(bm_pud), PUD_TYPE_TABLE);
827                 pudp = fixmap_pud(addr);
828         }
829         if (pud_none(READ_ONCE(*pudp)))
830                 __pud_populate(pudp, __pa_symbol(bm_pmd), PMD_TYPE_TABLE);
831         pmdp = fixmap_pmd(addr);
832         __pmd_populate(pmdp, __pa_symbol(bm_pte), PMD_TYPE_TABLE);
833 
834         /*
835          * The boot-ioremap range spans multiple pmds, for which
836          * we are not prepared:
837          */
838         BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT)
839                      != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT));
840 
841         if ((pmdp != fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)))
842              || pmdp != fixmap_pmd(fix_to_virt(FIX_BTMAP_END))) {
843                 WARN_ON(1);
844                 pr_warn("pmdp %p != %p, %p\n",
845                         pmdp, fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)),
846                         fixmap_pmd(fix_to_virt(FIX_BTMAP_END)));
847                 pr_warn("fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n",
848                         fix_to_virt(FIX_BTMAP_BEGIN));
849                 pr_warn("fix_to_virt(FIX_BTMAP_END):   %08lx\n",
850                         fix_to_virt(FIX_BTMAP_END));
851 
852                 pr_warn("FIX_BTMAP_END:       %d\n", FIX_BTMAP_END);
853                 pr_warn("FIX_BTMAP_BEGIN:     %d\n", FIX_BTMAP_BEGIN);
854         }
855 }
856 
857 /*
858  * Unusually, this is also called in IRQ context (ghes_iounmap_irq) so if we
859  * ever need to use IPIs for TLB broadcasting, then we're in trouble here.
860  */
861 void __set_fixmap(enum fixed_addresses idx,
862                                phys_addr_t phys, pgprot_t flags)
863 {
864         unsigned long addr = __fix_to_virt(idx);
865         pte_t *ptep;
866 
867         BUG_ON(idx <= FIX_HOLE || idx >= __end_of_fixed_addresses);
868 
869         ptep = fixmap_pte(addr);
870 
871         if (pgprot_val(flags)) {
872                 set_pte(ptep, pfn_pte(phys >> PAGE_SHIFT, flags));
873         } else {
874                 pte_clear(&init_mm, addr, ptep);
875                 flush_tlb_kernel_range(addr, addr+PAGE_SIZE);
876         }
877 }
878 
879 void *__init __fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot)
880 {
881         const u64 dt_virt_base = __fix_to_virt(FIX_FDT);
882         int offset;
883         void *dt_virt;
884 
885         /*
886          * Check whether the physical FDT address is set and meets the minimum
887          * alignment requirement. Since we are relying on MIN_FDT_ALIGN to be
888          * at least 8 bytes so that we can always access the magic and size
889          * fields of the FDT header after mapping the first chunk, double check
890          * here if that is indeed the case.
891          */
892         BUILD_BUG_ON(MIN_FDT_ALIGN < 8);
893         if (!dt_phys || dt_phys % MIN_FDT_ALIGN)
894                 return NULL;
895 
896         /*
897          * Make sure that the FDT region can be mapped without the need to
898          * allocate additional translation table pages, so that it is safe
899          * to call create_mapping_noalloc() this early.
900          *
901          * On 64k pages, the FDT will be mapped using PTEs, so we need to
902          * be in the same PMD as the rest of the fixmap.
903          * On 4k pages, we'll use section mappings for the FDT so we only
904          * have to be in the same PUD.
905          */
906         BUILD_BUG_ON(dt_virt_base % SZ_2M);
907 
908         BUILD_BUG_ON(__fix_to_virt(FIX_FDT_END) >> SWAPPER_TABLE_SHIFT !=
909                      __fix_to_virt(FIX_BTMAP_BEGIN) >> SWAPPER_TABLE_SHIFT);
910 
911         offset = dt_phys % SWAPPER_BLOCK_SIZE;
912         dt_virt = (void *)dt_virt_base + offset;
913 
914         /* map the first chunk so we can read the size from the header */
915         create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE),
916                         dt_virt_base, SWAPPER_BLOCK_SIZE, prot);
917 
918         if (fdt_magic(dt_virt) != FDT_MAGIC)
919                 return NULL;
920 
921         *size = fdt_totalsize(dt_virt);
922         if (*size > MAX_FDT_SIZE)
923                 return NULL;
924 
925         if (offset + *size > SWAPPER_BLOCK_SIZE)
926                 create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE), dt_virt_base,
927                                round_up(offset + *size, SWAPPER_BLOCK_SIZE), prot);
928 
929         return dt_virt;
930 }
931 
932 void *__init fixmap_remap_fdt(phys_addr_t dt_phys)
933 {
934         void *dt_virt;
935         int size;
936 
937         dt_virt = __fixmap_remap_fdt(dt_phys, &size, PAGE_KERNEL_RO);
938         if (!dt_virt)
939                 return NULL;
940 
941         memblock_reserve(dt_phys, size);
942         return dt_virt;
943 }
944 
945 int __init arch_ioremap_p4d_supported(void)
946 {
947         return 0;
948 }
949 
950 int __init arch_ioremap_pud_supported(void)
951 {
952         /*
953          * Only 4k granule supports level 1 block mappings.
954          * SW table walks can't handle removal of intermediate entries.
955          */
956         return IS_ENABLED(CONFIG_ARM64_4K_PAGES) &&
957                !IS_ENABLED(CONFIG_ARM64_PTDUMP_DEBUGFS);
958 }
959 
960 int __init arch_ioremap_pmd_supported(void)
961 {
962         /* See arch_ioremap_pud_supported() */
963         return !IS_ENABLED(CONFIG_ARM64_PTDUMP_DEBUGFS);
964 }
965 
966 int pud_set_huge(pud_t *pudp, phys_addr_t phys, pgprot_t prot)
967 {
968         pud_t new_pud = pfn_pud(__phys_to_pfn(phys), mk_pud_sect_prot(prot));
969 
970         /* Only allow permission changes for now */
971         if (!pgattr_change_is_safe(READ_ONCE(pud_val(*pudp)),
972                                    pud_val(new_pud)))
973                 return 0;
974 
975         VM_BUG_ON(phys & ~PUD_MASK);
976         set_pud(pudp, new_pud);
977         return 1;
978 }
979 
980 int pmd_set_huge(pmd_t *pmdp, phys_addr_t phys, pgprot_t prot)
981 {
982         pmd_t new_pmd = pfn_pmd(__phys_to_pfn(phys), mk_pmd_sect_prot(prot));
983 
984         /* Only allow permission changes for now */
985         if (!pgattr_change_is_safe(READ_ONCE(pmd_val(*pmdp)),
986                                    pmd_val(new_pmd)))
987                 return 0;
988 
989         VM_BUG_ON(phys & ~PMD_MASK);
990         set_pmd(pmdp, new_pmd);
991         return 1;
992 }
993 
994 int pud_clear_huge(pud_t *pudp)
995 {
996         if (!pud_sect(READ_ONCE(*pudp)))
997                 return 0;
998         pud_clear(pudp);
999         return 1;
1000 }
1001 
1002 int pmd_clear_huge(pmd_t *pmdp)
1003 {
1004         if (!pmd_sect(READ_ONCE(*pmdp)))
1005                 return 0;
1006         pmd_clear(pmdp);
1007         return 1;
1008 }
1009 
1010 int pmd_free_pte_page(pmd_t *pmdp, unsigned long addr)
1011 {
1012         pte_t *table;
1013         pmd_t pmd;
1014 
1015         pmd = READ_ONCE(*pmdp);
1016 
1017         if (!pmd_table(pmd)) {
1018                 VM_WARN_ON(1);
1019                 return 1;
1020         }
1021 
1022         table = pte_offset_kernel(pmdp, addr);
1023         pmd_clear(pmdp);
1024         __flush_tlb_kernel_pgtable(addr);
1025         pte_free_kernel(NULL, table);
1026         return 1;
1027 }
1028 
1029 int pud_free_pmd_page(pud_t *pudp, unsigned long addr)
1030 {
1031         pmd_t *table;
1032         pmd_t *pmdp;
1033         pud_t pud;
1034         unsigned long next, end;
1035 
1036         pud = READ_ONCE(*pudp);
1037 
1038         if (!pud_table(pud)) {
1039                 VM_WARN_ON(1);
1040                 return 1;
1041         }
1042 
1043         table = pmd_offset(pudp, addr);
1044         pmdp = table;
1045         next = addr;
1046         end = addr + PUD_SIZE;
1047         do {
1048                 pmd_free_pte_page(pmdp, next);
1049         } while (pmdp++, next += PMD_SIZE, next != end);
1050 
1051         pud_clear(pudp);
1052         __flush_tlb_kernel_pgtable(addr);
1053         pmd_free(NULL, table);
1054         return 1;
1055 }
1056 
1057 int p4d_free_pud_page(p4d_t *p4d, unsigned long addr)
1058 {
1059         return 0;       /* Don't attempt a block mapping */
1060 }
1061 
1062 #ifdef CONFIG_MEMORY_HOTPLUG
1063 int arch_add_memory(int nid, u64 start, u64 size,
1064                         struct mhp_restrictions *restrictions)
1065 {
1066         int flags = 0;
1067 
1068         if (rodata_full || debug_pagealloc_enabled())
1069                 flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;
1070 
1071         __create_pgd_mapping(swapper_pg_dir, start, __phys_to_virt(start),
1072                              size, PAGE_KERNEL, __pgd_pgtable_alloc, flags);
1073 
1074         return __add_pages(nid, start >> PAGE_SHIFT, size >> PAGE_SHIFT,
1075                            restrictions);
1076 }
1077 void arch_remove_memory(int nid, u64 start, u64 size,
1078                         struct vmem_altmap *altmap)
1079 {
1080         unsigned long start_pfn = start >> PAGE_SHIFT;
1081         unsigned long nr_pages = size >> PAGE_SHIFT;
1082         struct zone *zone;
1083 
1084         /*
1085          * FIXME: Cleanup page tables (also in arch_add_memory() in case
1086          * adding fails). Until then, this function should only be used
1087          * during memory hotplug (adding memory), not for memory
1088          * unplug. ARCH_ENABLE_MEMORY_HOTREMOVE must not be
1089          * unlocked yet.
1090          */
1091         zone = page_zone(pfn_to_page(start_pfn));
1092         __remove_pages(zone, start_pfn, nr_pages, altmap);
1093 }
1094 #endif
1095 

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