xref: /linux/arch/arm64/include/asm/pgtable.h (revision b72b5fecc1b8a2e595bd03d7d257c88ea3f9fd45)
1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  * Copyright (C) 2012 ARM Ltd.
4  */
5 #ifndef __ASM_PGTABLE_H
6 #define __ASM_PGTABLE_H
7 
8 #include <asm/bug.h>
9 #include <asm/proc-fns.h>
10 
11 #include <asm/memory.h>
12 #include <asm/mte.h>
13 #include <asm/pgtable-hwdef.h>
14 #include <asm/pgtable-prot.h>
15 #include <asm/tlbflush.h>
16 
17 /*
18  * VMALLOC range.
19  *
20  * VMALLOC_START: beginning of the kernel vmalloc space
21  * VMALLOC_END: extends to the available space below vmemmap, PCI I/O space
22  *	and fixed mappings
23  */
24 #define VMALLOC_START		(MODULES_END)
25 #define VMALLOC_END		(VMEMMAP_START - SZ_256M)
26 
27 #define vmemmap			((struct page *)VMEMMAP_START - (memstart_addr >> PAGE_SHIFT))
28 
29 #ifndef __ASSEMBLY__
30 
31 #include <asm/cmpxchg.h>
32 #include <asm/fixmap.h>
33 #include <linux/mmdebug.h>
34 #include <linux/mm_types.h>
35 #include <linux/sched.h>
36 #include <linux/page_table_check.h>
37 
38 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
39 #define __HAVE_ARCH_FLUSH_PMD_TLB_RANGE
40 
41 /* Set stride and tlb_level in flush_*_tlb_range */
42 #define flush_pmd_tlb_range(vma, addr, end)	\
43 	__flush_tlb_range(vma, addr, end, PMD_SIZE, false, 2)
44 #define flush_pud_tlb_range(vma, addr, end)	\
45 	__flush_tlb_range(vma, addr, end, PUD_SIZE, false, 1)
46 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
47 
48 static inline bool arch_thp_swp_supported(void)
49 {
50 	return !system_supports_mte();
51 }
52 #define arch_thp_swp_supported arch_thp_swp_supported
53 
54 /*
55  * Outside of a few very special situations (e.g. hibernation), we always
56  * use broadcast TLB invalidation instructions, therefore a spurious page
57  * fault on one CPU which has been handled concurrently by another CPU
58  * does not need to perform additional invalidation.
59  */
60 #define flush_tlb_fix_spurious_fault(vma, address) do { } while (0)
61 
62 /*
63  * ZERO_PAGE is a global shared page that is always zero: used
64  * for zero-mapped memory areas etc..
65  */
66 extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)];
67 #define ZERO_PAGE(vaddr)	phys_to_page(__pa_symbol(empty_zero_page))
68 
69 #define pte_ERROR(e)	\
70 	pr_err("%s:%d: bad pte %016llx.\n", __FILE__, __LINE__, pte_val(e))
71 
72 /*
73  * Macros to convert between a physical address and its placement in a
74  * page table entry, taking care of 52-bit addresses.
75  */
76 #ifdef CONFIG_ARM64_PA_BITS_52
77 static inline phys_addr_t __pte_to_phys(pte_t pte)
78 {
79 	return (pte_val(pte) & PTE_ADDR_LOW) |
80 		((pte_val(pte) & PTE_ADDR_HIGH) << PTE_ADDR_HIGH_SHIFT);
81 }
82 static inline pteval_t __phys_to_pte_val(phys_addr_t phys)
83 {
84 	return (phys | (phys >> PTE_ADDR_HIGH_SHIFT)) & PTE_ADDR_MASK;
85 }
86 #else
87 #define __pte_to_phys(pte)	(pte_val(pte) & PTE_ADDR_MASK)
88 #define __phys_to_pte_val(phys)	(phys)
89 #endif
90 
91 #define pte_pfn(pte)		(__pte_to_phys(pte) >> PAGE_SHIFT)
92 #define pfn_pte(pfn,prot)	\
93 	__pte(__phys_to_pte_val((phys_addr_t)(pfn) << PAGE_SHIFT) | pgprot_val(prot))
94 
95 #define pte_none(pte)		(!pte_val(pte))
96 #define pte_clear(mm,addr,ptep)	set_pte(ptep, __pte(0))
97 #define pte_page(pte)		(pfn_to_page(pte_pfn(pte)))
98 
99 /*
100  * The following only work if pte_present(). Undefined behaviour otherwise.
101  */
102 #define pte_present(pte)	(!!(pte_val(pte) & (PTE_VALID | PTE_PROT_NONE)))
103 #define pte_young(pte)		(!!(pte_val(pte) & PTE_AF))
104 #define pte_special(pte)	(!!(pte_val(pte) & PTE_SPECIAL))
105 #define pte_write(pte)		(!!(pte_val(pte) & PTE_WRITE))
106 #define pte_user(pte)		(!!(pte_val(pte) & PTE_USER))
107 #define pte_user_exec(pte)	(!(pte_val(pte) & PTE_UXN))
108 #define pte_cont(pte)		(!!(pte_val(pte) & PTE_CONT))
109 #define pte_devmap(pte)		(!!(pte_val(pte) & PTE_DEVMAP))
110 #define pte_tagged(pte)		((pte_val(pte) & PTE_ATTRINDX_MASK) == \
111 				 PTE_ATTRINDX(MT_NORMAL_TAGGED))
112 
113 #define pte_cont_addr_end(addr, end)						\
114 ({	unsigned long __boundary = ((addr) + CONT_PTE_SIZE) & CONT_PTE_MASK;	\
115 	(__boundary - 1 < (end) - 1) ? __boundary : (end);			\
116 })
117 
118 #define pmd_cont_addr_end(addr, end)						\
119 ({	unsigned long __boundary = ((addr) + CONT_PMD_SIZE) & CONT_PMD_MASK;	\
120 	(__boundary - 1 < (end) - 1) ? __boundary : (end);			\
121 })
122 
123 #define pte_hw_dirty(pte)	(pte_write(pte) && !(pte_val(pte) & PTE_RDONLY))
124 #define pte_sw_dirty(pte)	(!!(pte_val(pte) & PTE_DIRTY))
125 #define pte_dirty(pte)		(pte_sw_dirty(pte) || pte_hw_dirty(pte))
126 
127 #define pte_valid(pte)		(!!(pte_val(pte) & PTE_VALID))
128 /*
129  * Execute-only user mappings do not have the PTE_USER bit set. All valid
130  * kernel mappings have the PTE_UXN bit set.
131  */
132 #define pte_valid_not_user(pte) \
133 	((pte_val(pte) & (PTE_VALID | PTE_USER | PTE_UXN)) == (PTE_VALID | PTE_UXN))
134 /*
135  * Could the pte be present in the TLB? We must check mm_tlb_flush_pending
136  * so that we don't erroneously return false for pages that have been
137  * remapped as PROT_NONE but are yet to be flushed from the TLB.
138  * Note that we can't make any assumptions based on the state of the access
139  * flag, since ptep_clear_flush_young() elides a DSB when invalidating the
140  * TLB.
141  */
142 #define pte_accessible(mm, pte)	\
143 	(mm_tlb_flush_pending(mm) ? pte_present(pte) : pte_valid(pte))
144 
145 /*
146  * p??_access_permitted() is true for valid user mappings (PTE_USER
147  * bit set, subject to the write permission check). For execute-only
148  * mappings, like PROT_EXEC with EPAN (both PTE_USER and PTE_UXN bits
149  * not set) must return false. PROT_NONE mappings do not have the
150  * PTE_VALID bit set.
151  */
152 #define pte_access_permitted(pte, write) \
153 	(((pte_val(pte) & (PTE_VALID | PTE_USER)) == (PTE_VALID | PTE_USER)) && (!(write) || pte_write(pte)))
154 #define pmd_access_permitted(pmd, write) \
155 	(pte_access_permitted(pmd_pte(pmd), (write)))
156 #define pud_access_permitted(pud, write) \
157 	(pte_access_permitted(pud_pte(pud), (write)))
158 
159 static inline pte_t clear_pte_bit(pte_t pte, pgprot_t prot)
160 {
161 	pte_val(pte) &= ~pgprot_val(prot);
162 	return pte;
163 }
164 
165 static inline pte_t set_pte_bit(pte_t pte, pgprot_t prot)
166 {
167 	pte_val(pte) |= pgprot_val(prot);
168 	return pte;
169 }
170 
171 static inline pmd_t clear_pmd_bit(pmd_t pmd, pgprot_t prot)
172 {
173 	pmd_val(pmd) &= ~pgprot_val(prot);
174 	return pmd;
175 }
176 
177 static inline pmd_t set_pmd_bit(pmd_t pmd, pgprot_t prot)
178 {
179 	pmd_val(pmd) |= pgprot_val(prot);
180 	return pmd;
181 }
182 
183 static inline pte_t pte_mkwrite(pte_t pte)
184 {
185 	pte = set_pte_bit(pte, __pgprot(PTE_WRITE));
186 	pte = clear_pte_bit(pte, __pgprot(PTE_RDONLY));
187 	return pte;
188 }
189 
190 static inline pte_t pte_mkclean(pte_t pte)
191 {
192 	pte = clear_pte_bit(pte, __pgprot(PTE_DIRTY));
193 	pte = set_pte_bit(pte, __pgprot(PTE_RDONLY));
194 
195 	return pte;
196 }
197 
198 static inline pte_t pte_mkdirty(pte_t pte)
199 {
200 	pte = set_pte_bit(pte, __pgprot(PTE_DIRTY));
201 
202 	if (pte_write(pte))
203 		pte = clear_pte_bit(pte, __pgprot(PTE_RDONLY));
204 
205 	return pte;
206 }
207 
208 static inline pte_t pte_wrprotect(pte_t pte)
209 {
210 	/*
211 	 * If hardware-dirty (PTE_WRITE/DBM bit set and PTE_RDONLY
212 	 * clear), set the PTE_DIRTY bit.
213 	 */
214 	if (pte_hw_dirty(pte))
215 		pte = pte_mkdirty(pte);
216 
217 	pte = clear_pte_bit(pte, __pgprot(PTE_WRITE));
218 	pte = set_pte_bit(pte, __pgprot(PTE_RDONLY));
219 	return pte;
220 }
221 
222 static inline pte_t pte_mkold(pte_t pte)
223 {
224 	return clear_pte_bit(pte, __pgprot(PTE_AF));
225 }
226 
227 static inline pte_t pte_mkyoung(pte_t pte)
228 {
229 	return set_pte_bit(pte, __pgprot(PTE_AF));
230 }
231 
232 static inline pte_t pte_mkspecial(pte_t pte)
233 {
234 	return set_pte_bit(pte, __pgprot(PTE_SPECIAL));
235 }
236 
237 static inline pte_t pte_mkcont(pte_t pte)
238 {
239 	pte = set_pte_bit(pte, __pgprot(PTE_CONT));
240 	return set_pte_bit(pte, __pgprot(PTE_TYPE_PAGE));
241 }
242 
243 static inline pte_t pte_mknoncont(pte_t pte)
244 {
245 	return clear_pte_bit(pte, __pgprot(PTE_CONT));
246 }
247 
248 static inline pte_t pte_mkpresent(pte_t pte)
249 {
250 	return set_pte_bit(pte, __pgprot(PTE_VALID));
251 }
252 
253 static inline pmd_t pmd_mkcont(pmd_t pmd)
254 {
255 	return __pmd(pmd_val(pmd) | PMD_SECT_CONT);
256 }
257 
258 static inline pte_t pte_mkdevmap(pte_t pte)
259 {
260 	return set_pte_bit(pte, __pgprot(PTE_DEVMAP | PTE_SPECIAL));
261 }
262 
263 static inline void set_pte(pte_t *ptep, pte_t pte)
264 {
265 	WRITE_ONCE(*ptep, pte);
266 
267 	/*
268 	 * Only if the new pte is valid and kernel, otherwise TLB maintenance
269 	 * or update_mmu_cache() have the necessary barriers.
270 	 */
271 	if (pte_valid_not_user(pte)) {
272 		dsb(ishst);
273 		isb();
274 	}
275 }
276 
277 extern void __sync_icache_dcache(pte_t pteval);
278 bool pgattr_change_is_safe(u64 old, u64 new);
279 
280 /*
281  * PTE bits configuration in the presence of hardware Dirty Bit Management
282  * (PTE_WRITE == PTE_DBM):
283  *
284  * Dirty  Writable | PTE_RDONLY  PTE_WRITE  PTE_DIRTY (sw)
285  *   0      0      |   1           0          0
286  *   0      1      |   1           1          0
287  *   1      0      |   1           0          1
288  *   1      1      |   0           1          x
289  *
290  * When hardware DBM is not present, the sofware PTE_DIRTY bit is updated via
291  * the page fault mechanism. Checking the dirty status of a pte becomes:
292  *
293  *   PTE_DIRTY || (PTE_WRITE && !PTE_RDONLY)
294  */
295 
296 static inline void __check_safe_pte_update(struct mm_struct *mm, pte_t *ptep,
297 					   pte_t pte)
298 {
299 	pte_t old_pte;
300 
301 	if (!IS_ENABLED(CONFIG_DEBUG_VM))
302 		return;
303 
304 	old_pte = READ_ONCE(*ptep);
305 
306 	if (!pte_valid(old_pte) || !pte_valid(pte))
307 		return;
308 	if (mm != current->active_mm && atomic_read(&mm->mm_users) <= 1)
309 		return;
310 
311 	/*
312 	 * Check for potential race with hardware updates of the pte
313 	 * (ptep_set_access_flags safely changes valid ptes without going
314 	 * through an invalid entry).
315 	 */
316 	VM_WARN_ONCE(!pte_young(pte),
317 		     "%s: racy access flag clearing: 0x%016llx -> 0x%016llx",
318 		     __func__, pte_val(old_pte), pte_val(pte));
319 	VM_WARN_ONCE(pte_write(old_pte) && !pte_dirty(pte),
320 		     "%s: racy dirty state clearing: 0x%016llx -> 0x%016llx",
321 		     __func__, pte_val(old_pte), pte_val(pte));
322 	VM_WARN_ONCE(!pgattr_change_is_safe(pte_val(old_pte), pte_val(pte)),
323 		     "%s: unsafe attribute change: 0x%016llx -> 0x%016llx",
324 		     __func__, pte_val(old_pte), pte_val(pte));
325 }
326 
327 static inline void __set_pte_at(struct mm_struct *mm, unsigned long addr,
328 				pte_t *ptep, pte_t pte)
329 {
330 	if (pte_present(pte) && pte_user_exec(pte) && !pte_special(pte))
331 		__sync_icache_dcache(pte);
332 
333 	/*
334 	 * If the PTE would provide user space access to the tags associated
335 	 * with it then ensure that the MTE tags are synchronised.  Although
336 	 * pte_access_permitted() returns false for exec only mappings, they
337 	 * don't expose tags (instruction fetches don't check tags).
338 	 */
339 	if (system_supports_mte() && pte_access_permitted(pte, false) &&
340 	    !pte_special(pte)) {
341 		pte_t old_pte = READ_ONCE(*ptep);
342 		/*
343 		 * We only need to synchronise if the new PTE has tags enabled
344 		 * or if swapping in (in which case another mapping may have
345 		 * set tags in the past even if this PTE isn't tagged).
346 		 * (!pte_none() && !pte_present()) is an open coded version of
347 		 * is_swap_pte()
348 		 */
349 		if (pte_tagged(pte) || (!pte_none(old_pte) && !pte_present(old_pte)))
350 			mte_sync_tags(old_pte, pte);
351 	}
352 
353 	__check_safe_pte_update(mm, ptep, pte);
354 
355 	set_pte(ptep, pte);
356 }
357 
358 static inline void set_pte_at(struct mm_struct *mm, unsigned long addr,
359 			      pte_t *ptep, pte_t pte)
360 {
361 	page_table_check_pte_set(mm, addr, ptep, pte);
362 	return __set_pte_at(mm, addr, ptep, pte);
363 }
364 
365 /*
366  * Huge pte definitions.
367  */
368 #define pte_mkhuge(pte)		(__pte(pte_val(pte) & ~PTE_TABLE_BIT))
369 
370 /*
371  * Hugetlb definitions.
372  */
373 #define HUGE_MAX_HSTATE		4
374 #define HPAGE_SHIFT		PMD_SHIFT
375 #define HPAGE_SIZE		(_AC(1, UL) << HPAGE_SHIFT)
376 #define HPAGE_MASK		(~(HPAGE_SIZE - 1))
377 #define HUGETLB_PAGE_ORDER	(HPAGE_SHIFT - PAGE_SHIFT)
378 
379 static inline pte_t pgd_pte(pgd_t pgd)
380 {
381 	return __pte(pgd_val(pgd));
382 }
383 
384 static inline pte_t p4d_pte(p4d_t p4d)
385 {
386 	return __pte(p4d_val(p4d));
387 }
388 
389 static inline pte_t pud_pte(pud_t pud)
390 {
391 	return __pte(pud_val(pud));
392 }
393 
394 static inline pud_t pte_pud(pte_t pte)
395 {
396 	return __pud(pte_val(pte));
397 }
398 
399 static inline pmd_t pud_pmd(pud_t pud)
400 {
401 	return __pmd(pud_val(pud));
402 }
403 
404 static inline pte_t pmd_pte(pmd_t pmd)
405 {
406 	return __pte(pmd_val(pmd));
407 }
408 
409 static inline pmd_t pte_pmd(pte_t pte)
410 {
411 	return __pmd(pte_val(pte));
412 }
413 
414 static inline pgprot_t mk_pud_sect_prot(pgprot_t prot)
415 {
416 	return __pgprot((pgprot_val(prot) & ~PUD_TABLE_BIT) | PUD_TYPE_SECT);
417 }
418 
419 static inline pgprot_t mk_pmd_sect_prot(pgprot_t prot)
420 {
421 	return __pgprot((pgprot_val(prot) & ~PMD_TABLE_BIT) | PMD_TYPE_SECT);
422 }
423 
424 #define __HAVE_ARCH_PTE_SWP_EXCLUSIVE
425 static inline pte_t pte_swp_mkexclusive(pte_t pte)
426 {
427 	return set_pte_bit(pte, __pgprot(PTE_SWP_EXCLUSIVE));
428 }
429 
430 static inline int pte_swp_exclusive(pte_t pte)
431 {
432 	return pte_val(pte) & PTE_SWP_EXCLUSIVE;
433 }
434 
435 static inline pte_t pte_swp_clear_exclusive(pte_t pte)
436 {
437 	return clear_pte_bit(pte, __pgprot(PTE_SWP_EXCLUSIVE));
438 }
439 
440 /*
441  * Select all bits except the pfn
442  */
443 static inline pgprot_t pte_pgprot(pte_t pte)
444 {
445 	unsigned long pfn = pte_pfn(pte);
446 
447 	return __pgprot(pte_val(pfn_pte(pfn, __pgprot(0))) ^ pte_val(pte));
448 }
449 
450 #ifdef CONFIG_NUMA_BALANCING
451 /*
452  * See the comment in include/linux/pgtable.h
453  */
454 static inline int pte_protnone(pte_t pte)
455 {
456 	return (pte_val(pte) & (PTE_VALID | PTE_PROT_NONE)) == PTE_PROT_NONE;
457 }
458 
459 static inline int pmd_protnone(pmd_t pmd)
460 {
461 	return pte_protnone(pmd_pte(pmd));
462 }
463 #endif
464 
465 #define pmd_present_invalid(pmd)     (!!(pmd_val(pmd) & PMD_PRESENT_INVALID))
466 
467 static inline int pmd_present(pmd_t pmd)
468 {
469 	return pte_present(pmd_pte(pmd)) || pmd_present_invalid(pmd);
470 }
471 
472 /*
473  * THP definitions.
474  */
475 
476 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
477 static inline int pmd_trans_huge(pmd_t pmd)
478 {
479 	return pmd_val(pmd) && pmd_present(pmd) && !(pmd_val(pmd) & PMD_TABLE_BIT);
480 }
481 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
482 
483 #define pmd_dirty(pmd)		pte_dirty(pmd_pte(pmd))
484 #define pmd_young(pmd)		pte_young(pmd_pte(pmd))
485 #define pmd_valid(pmd)		pte_valid(pmd_pte(pmd))
486 #define pmd_user(pmd)		pte_user(pmd_pte(pmd))
487 #define pmd_user_exec(pmd)	pte_user_exec(pmd_pte(pmd))
488 #define pmd_cont(pmd)		pte_cont(pmd_pte(pmd))
489 #define pmd_wrprotect(pmd)	pte_pmd(pte_wrprotect(pmd_pte(pmd)))
490 #define pmd_mkold(pmd)		pte_pmd(pte_mkold(pmd_pte(pmd)))
491 #define pmd_mkwrite(pmd)	pte_pmd(pte_mkwrite(pmd_pte(pmd)))
492 #define pmd_mkclean(pmd)	pte_pmd(pte_mkclean(pmd_pte(pmd)))
493 #define pmd_mkdirty(pmd)	pte_pmd(pte_mkdirty(pmd_pte(pmd)))
494 #define pmd_mkyoung(pmd)	pte_pmd(pte_mkyoung(pmd_pte(pmd)))
495 
496 static inline pmd_t pmd_mkinvalid(pmd_t pmd)
497 {
498 	pmd = set_pmd_bit(pmd, __pgprot(PMD_PRESENT_INVALID));
499 	pmd = clear_pmd_bit(pmd, __pgprot(PMD_SECT_VALID));
500 
501 	return pmd;
502 }
503 
504 #define pmd_thp_or_huge(pmd)	(pmd_huge(pmd) || pmd_trans_huge(pmd))
505 
506 #define pmd_write(pmd)		pte_write(pmd_pte(pmd))
507 
508 #define pmd_mkhuge(pmd)		(__pmd(pmd_val(pmd) & ~PMD_TABLE_BIT))
509 
510 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
511 #define pmd_devmap(pmd)		pte_devmap(pmd_pte(pmd))
512 #endif
513 static inline pmd_t pmd_mkdevmap(pmd_t pmd)
514 {
515 	return pte_pmd(set_pte_bit(pmd_pte(pmd), __pgprot(PTE_DEVMAP)));
516 }
517 
518 #define __pmd_to_phys(pmd)	__pte_to_phys(pmd_pte(pmd))
519 #define __phys_to_pmd_val(phys)	__phys_to_pte_val(phys)
520 #define pmd_pfn(pmd)		((__pmd_to_phys(pmd) & PMD_MASK) >> PAGE_SHIFT)
521 #define pfn_pmd(pfn,prot)	__pmd(__phys_to_pmd_val((phys_addr_t)(pfn) << PAGE_SHIFT) | pgprot_val(prot))
522 #define mk_pmd(page,prot)	pfn_pmd(page_to_pfn(page),prot)
523 
524 #define pud_young(pud)		pte_young(pud_pte(pud))
525 #define pud_mkyoung(pud)	pte_pud(pte_mkyoung(pud_pte(pud)))
526 #define pud_write(pud)		pte_write(pud_pte(pud))
527 
528 #define pud_mkhuge(pud)		(__pud(pud_val(pud) & ~PUD_TABLE_BIT))
529 
530 #define __pud_to_phys(pud)	__pte_to_phys(pud_pte(pud))
531 #define __phys_to_pud_val(phys)	__phys_to_pte_val(phys)
532 #define pud_pfn(pud)		((__pud_to_phys(pud) & PUD_MASK) >> PAGE_SHIFT)
533 #define pfn_pud(pfn,prot)	__pud(__phys_to_pud_val((phys_addr_t)(pfn) << PAGE_SHIFT) | pgprot_val(prot))
534 
535 static inline void set_pmd_at(struct mm_struct *mm, unsigned long addr,
536 			      pmd_t *pmdp, pmd_t pmd)
537 {
538 	page_table_check_pmd_set(mm, addr, pmdp, pmd);
539 	return __set_pte_at(mm, addr, (pte_t *)pmdp, pmd_pte(pmd));
540 }
541 
542 static inline void set_pud_at(struct mm_struct *mm, unsigned long addr,
543 			      pud_t *pudp, pud_t pud)
544 {
545 	page_table_check_pud_set(mm, addr, pudp, pud);
546 	return __set_pte_at(mm, addr, (pte_t *)pudp, pud_pte(pud));
547 }
548 
549 #define __p4d_to_phys(p4d)	__pte_to_phys(p4d_pte(p4d))
550 #define __phys_to_p4d_val(phys)	__phys_to_pte_val(phys)
551 
552 #define __pgd_to_phys(pgd)	__pte_to_phys(pgd_pte(pgd))
553 #define __phys_to_pgd_val(phys)	__phys_to_pte_val(phys)
554 
555 #define __pgprot_modify(prot,mask,bits) \
556 	__pgprot((pgprot_val(prot) & ~(mask)) | (bits))
557 
558 #define pgprot_nx(prot) \
559 	__pgprot_modify(prot, PTE_MAYBE_GP, PTE_PXN)
560 
561 /*
562  * Mark the prot value as uncacheable and unbufferable.
563  */
564 #define pgprot_noncached(prot) \
565 	__pgprot_modify(prot, PTE_ATTRINDX_MASK, PTE_ATTRINDX(MT_DEVICE_nGnRnE) | PTE_PXN | PTE_UXN)
566 #define pgprot_writecombine(prot) \
567 	__pgprot_modify(prot, PTE_ATTRINDX_MASK, PTE_ATTRINDX(MT_NORMAL_NC) | PTE_PXN | PTE_UXN)
568 #define pgprot_device(prot) \
569 	__pgprot_modify(prot, PTE_ATTRINDX_MASK, PTE_ATTRINDX(MT_DEVICE_nGnRE) | PTE_PXN | PTE_UXN)
570 #define pgprot_tagged(prot) \
571 	__pgprot_modify(prot, PTE_ATTRINDX_MASK, PTE_ATTRINDX(MT_NORMAL_TAGGED))
572 #define pgprot_mhp	pgprot_tagged
573 /*
574  * DMA allocations for non-coherent devices use what the Arm architecture calls
575  * "Normal non-cacheable" memory, which permits speculation, unaligned accesses
576  * and merging of writes.  This is different from "Device-nGnR[nE]" memory which
577  * is intended for MMIO and thus forbids speculation, preserves access size,
578  * requires strict alignment and can also force write responses to come from the
579  * endpoint.
580  */
581 #define pgprot_dmacoherent(prot) \
582 	__pgprot_modify(prot, PTE_ATTRINDX_MASK, \
583 			PTE_ATTRINDX(MT_NORMAL_NC) | PTE_PXN | PTE_UXN)
584 
585 #define __HAVE_PHYS_MEM_ACCESS_PROT
586 struct file;
587 extern pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
588 				     unsigned long size, pgprot_t vma_prot);
589 
590 #define pmd_none(pmd)		(!pmd_val(pmd))
591 
592 #define pmd_table(pmd)		((pmd_val(pmd) & PMD_TYPE_MASK) == \
593 				 PMD_TYPE_TABLE)
594 #define pmd_sect(pmd)		((pmd_val(pmd) & PMD_TYPE_MASK) == \
595 				 PMD_TYPE_SECT)
596 #define pmd_leaf(pmd)		(pmd_present(pmd) && !pmd_table(pmd))
597 #define pmd_bad(pmd)		(!pmd_table(pmd))
598 
599 #define pmd_leaf_size(pmd)	(pmd_cont(pmd) ? CONT_PMD_SIZE : PMD_SIZE)
600 #define pte_leaf_size(pte)	(pte_cont(pte) ? CONT_PTE_SIZE : PAGE_SIZE)
601 
602 #if defined(CONFIG_ARM64_64K_PAGES) || CONFIG_PGTABLE_LEVELS < 3
603 static inline bool pud_sect(pud_t pud) { return false; }
604 static inline bool pud_table(pud_t pud) { return true; }
605 #else
606 #define pud_sect(pud)		((pud_val(pud) & PUD_TYPE_MASK) == \
607 				 PUD_TYPE_SECT)
608 #define pud_table(pud)		((pud_val(pud) & PUD_TYPE_MASK) == \
609 				 PUD_TYPE_TABLE)
610 #endif
611 
612 extern pgd_t init_pg_dir[PTRS_PER_PGD];
613 extern pgd_t init_pg_end[];
614 extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
615 extern pgd_t idmap_pg_dir[PTRS_PER_PGD];
616 extern pgd_t tramp_pg_dir[PTRS_PER_PGD];
617 extern pgd_t reserved_pg_dir[PTRS_PER_PGD];
618 
619 extern void set_swapper_pgd(pgd_t *pgdp, pgd_t pgd);
620 
621 static inline bool in_swapper_pgdir(void *addr)
622 {
623 	return ((unsigned long)addr & PAGE_MASK) ==
624 	        ((unsigned long)swapper_pg_dir & PAGE_MASK);
625 }
626 
627 static inline void set_pmd(pmd_t *pmdp, pmd_t pmd)
628 {
629 #ifdef __PAGETABLE_PMD_FOLDED
630 	if (in_swapper_pgdir(pmdp)) {
631 		set_swapper_pgd((pgd_t *)pmdp, __pgd(pmd_val(pmd)));
632 		return;
633 	}
634 #endif /* __PAGETABLE_PMD_FOLDED */
635 
636 	WRITE_ONCE(*pmdp, pmd);
637 
638 	if (pmd_valid(pmd)) {
639 		dsb(ishst);
640 		isb();
641 	}
642 }
643 
644 static inline void pmd_clear(pmd_t *pmdp)
645 {
646 	set_pmd(pmdp, __pmd(0));
647 }
648 
649 static inline phys_addr_t pmd_page_paddr(pmd_t pmd)
650 {
651 	return __pmd_to_phys(pmd);
652 }
653 
654 static inline unsigned long pmd_page_vaddr(pmd_t pmd)
655 {
656 	return (unsigned long)__va(pmd_page_paddr(pmd));
657 }
658 
659 /* Find an entry in the third-level page table. */
660 #define pte_offset_phys(dir,addr)	(pmd_page_paddr(READ_ONCE(*(dir))) + pte_index(addr) * sizeof(pte_t))
661 
662 #define pte_set_fixmap(addr)		((pte_t *)set_fixmap_offset(FIX_PTE, addr))
663 #define pte_set_fixmap_offset(pmd, addr)	pte_set_fixmap(pte_offset_phys(pmd, addr))
664 #define pte_clear_fixmap()		clear_fixmap(FIX_PTE)
665 
666 #define pmd_page(pmd)			phys_to_page(__pmd_to_phys(pmd))
667 
668 /* use ONLY for statically allocated translation tables */
669 #define pte_offset_kimg(dir,addr)	((pte_t *)__phys_to_kimg(pte_offset_phys((dir), (addr))))
670 
671 /*
672  * Conversion functions: convert a page and protection to a page entry,
673  * and a page entry and page directory to the page they refer to.
674  */
675 #define mk_pte(page,prot)	pfn_pte(page_to_pfn(page),prot)
676 
677 #if CONFIG_PGTABLE_LEVELS > 2
678 
679 #define pmd_ERROR(e)	\
680 	pr_err("%s:%d: bad pmd %016llx.\n", __FILE__, __LINE__, pmd_val(e))
681 
682 #define pud_none(pud)		(!pud_val(pud))
683 #define pud_bad(pud)		(!pud_table(pud))
684 #define pud_present(pud)	pte_present(pud_pte(pud))
685 #define pud_leaf(pud)		(pud_present(pud) && !pud_table(pud))
686 #define pud_valid(pud)		pte_valid(pud_pte(pud))
687 #define pud_user(pud)		pte_user(pud_pte(pud))
688 #define pud_user_exec(pud)	pte_user_exec(pud_pte(pud))
689 
690 static inline void set_pud(pud_t *pudp, pud_t pud)
691 {
692 #ifdef __PAGETABLE_PUD_FOLDED
693 	if (in_swapper_pgdir(pudp)) {
694 		set_swapper_pgd((pgd_t *)pudp, __pgd(pud_val(pud)));
695 		return;
696 	}
697 #endif /* __PAGETABLE_PUD_FOLDED */
698 
699 	WRITE_ONCE(*pudp, pud);
700 
701 	if (pud_valid(pud)) {
702 		dsb(ishst);
703 		isb();
704 	}
705 }
706 
707 static inline void pud_clear(pud_t *pudp)
708 {
709 	set_pud(pudp, __pud(0));
710 }
711 
712 static inline phys_addr_t pud_page_paddr(pud_t pud)
713 {
714 	return __pud_to_phys(pud);
715 }
716 
717 static inline pmd_t *pud_pgtable(pud_t pud)
718 {
719 	return (pmd_t *)__va(pud_page_paddr(pud));
720 }
721 
722 /* Find an entry in the second-level page table. */
723 #define pmd_offset_phys(dir, addr)	(pud_page_paddr(READ_ONCE(*(dir))) + pmd_index(addr) * sizeof(pmd_t))
724 
725 #define pmd_set_fixmap(addr)		((pmd_t *)set_fixmap_offset(FIX_PMD, addr))
726 #define pmd_set_fixmap_offset(pud, addr)	pmd_set_fixmap(pmd_offset_phys(pud, addr))
727 #define pmd_clear_fixmap()		clear_fixmap(FIX_PMD)
728 
729 #define pud_page(pud)			phys_to_page(__pud_to_phys(pud))
730 
731 /* use ONLY for statically allocated translation tables */
732 #define pmd_offset_kimg(dir,addr)	((pmd_t *)__phys_to_kimg(pmd_offset_phys((dir), (addr))))
733 
734 #else
735 
736 #define pud_page_paddr(pud)	({ BUILD_BUG(); 0; })
737 #define pud_user_exec(pud)	pud_user(pud) /* Always 0 with folding */
738 
739 /* Match pmd_offset folding in <asm/generic/pgtable-nopmd.h> */
740 #define pmd_set_fixmap(addr)		NULL
741 #define pmd_set_fixmap_offset(pudp, addr)	((pmd_t *)pudp)
742 #define pmd_clear_fixmap()
743 
744 #define pmd_offset_kimg(dir,addr)	((pmd_t *)dir)
745 
746 #endif	/* CONFIG_PGTABLE_LEVELS > 2 */
747 
748 #if CONFIG_PGTABLE_LEVELS > 3
749 
750 #define pud_ERROR(e)	\
751 	pr_err("%s:%d: bad pud %016llx.\n", __FILE__, __LINE__, pud_val(e))
752 
753 #define p4d_none(p4d)		(!p4d_val(p4d))
754 #define p4d_bad(p4d)		(!(p4d_val(p4d) & 2))
755 #define p4d_present(p4d)	(p4d_val(p4d))
756 
757 static inline void set_p4d(p4d_t *p4dp, p4d_t p4d)
758 {
759 	if (in_swapper_pgdir(p4dp)) {
760 		set_swapper_pgd((pgd_t *)p4dp, __pgd(p4d_val(p4d)));
761 		return;
762 	}
763 
764 	WRITE_ONCE(*p4dp, p4d);
765 	dsb(ishst);
766 	isb();
767 }
768 
769 static inline void p4d_clear(p4d_t *p4dp)
770 {
771 	set_p4d(p4dp, __p4d(0));
772 }
773 
774 static inline phys_addr_t p4d_page_paddr(p4d_t p4d)
775 {
776 	return __p4d_to_phys(p4d);
777 }
778 
779 static inline pud_t *p4d_pgtable(p4d_t p4d)
780 {
781 	return (pud_t *)__va(p4d_page_paddr(p4d));
782 }
783 
784 /* Find an entry in the first-level page table. */
785 #define pud_offset_phys(dir, addr)	(p4d_page_paddr(READ_ONCE(*(dir))) + pud_index(addr) * sizeof(pud_t))
786 
787 #define pud_set_fixmap(addr)		((pud_t *)set_fixmap_offset(FIX_PUD, addr))
788 #define pud_set_fixmap_offset(p4d, addr)	pud_set_fixmap(pud_offset_phys(p4d, addr))
789 #define pud_clear_fixmap()		clear_fixmap(FIX_PUD)
790 
791 #define p4d_page(p4d)		pfn_to_page(__phys_to_pfn(__p4d_to_phys(p4d)))
792 
793 /* use ONLY for statically allocated translation tables */
794 #define pud_offset_kimg(dir,addr)	((pud_t *)__phys_to_kimg(pud_offset_phys((dir), (addr))))
795 
796 #else
797 
798 #define p4d_page_paddr(p4d)	({ BUILD_BUG(); 0;})
799 #define pgd_page_paddr(pgd)	({ BUILD_BUG(); 0;})
800 
801 /* Match pud_offset folding in <asm/generic/pgtable-nopud.h> */
802 #define pud_set_fixmap(addr)		NULL
803 #define pud_set_fixmap_offset(pgdp, addr)	((pud_t *)pgdp)
804 #define pud_clear_fixmap()
805 
806 #define pud_offset_kimg(dir,addr)	((pud_t *)dir)
807 
808 #endif  /* CONFIG_PGTABLE_LEVELS > 3 */
809 
810 #define pgd_ERROR(e)	\
811 	pr_err("%s:%d: bad pgd %016llx.\n", __FILE__, __LINE__, pgd_val(e))
812 
813 #define pgd_set_fixmap(addr)	((pgd_t *)set_fixmap_offset(FIX_PGD, addr))
814 #define pgd_clear_fixmap()	clear_fixmap(FIX_PGD)
815 
816 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
817 {
818 	/*
819 	 * Normal and Normal-Tagged are two different memory types and indices
820 	 * in MAIR_EL1. The mask below has to include PTE_ATTRINDX_MASK.
821 	 */
822 	const pteval_t mask = PTE_USER | PTE_PXN | PTE_UXN | PTE_RDONLY |
823 			      PTE_PROT_NONE | PTE_VALID | PTE_WRITE | PTE_GP |
824 			      PTE_ATTRINDX_MASK;
825 	/* preserve the hardware dirty information */
826 	if (pte_hw_dirty(pte))
827 		pte = pte_mkdirty(pte);
828 	pte_val(pte) = (pte_val(pte) & ~mask) | (pgprot_val(newprot) & mask);
829 	return pte;
830 }
831 
832 static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot)
833 {
834 	return pte_pmd(pte_modify(pmd_pte(pmd), newprot));
835 }
836 
837 #define __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
838 extern int ptep_set_access_flags(struct vm_area_struct *vma,
839 				 unsigned long address, pte_t *ptep,
840 				 pte_t entry, int dirty);
841 
842 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
843 #define __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS
844 static inline int pmdp_set_access_flags(struct vm_area_struct *vma,
845 					unsigned long address, pmd_t *pmdp,
846 					pmd_t entry, int dirty)
847 {
848 	return ptep_set_access_flags(vma, address, (pte_t *)pmdp, pmd_pte(entry), dirty);
849 }
850 
851 static inline int pud_devmap(pud_t pud)
852 {
853 	return 0;
854 }
855 
856 static inline int pgd_devmap(pgd_t pgd)
857 {
858 	return 0;
859 }
860 #endif
861 
862 #ifdef CONFIG_PAGE_TABLE_CHECK
863 static inline bool pte_user_accessible_page(pte_t pte)
864 {
865 	return pte_present(pte) && (pte_user(pte) || pte_user_exec(pte));
866 }
867 
868 static inline bool pmd_user_accessible_page(pmd_t pmd)
869 {
870 	return pmd_leaf(pmd) && !pmd_present_invalid(pmd) && (pmd_user(pmd) || pmd_user_exec(pmd));
871 }
872 
873 static inline bool pud_user_accessible_page(pud_t pud)
874 {
875 	return pud_leaf(pud) && (pud_user(pud) || pud_user_exec(pud));
876 }
877 #endif
878 
879 /*
880  * Atomic pte/pmd modifications.
881  */
882 #define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
883 static inline int __ptep_test_and_clear_young(pte_t *ptep)
884 {
885 	pte_t old_pte, pte;
886 
887 	pte = READ_ONCE(*ptep);
888 	do {
889 		old_pte = pte;
890 		pte = pte_mkold(pte);
891 		pte_val(pte) = cmpxchg_relaxed(&pte_val(*ptep),
892 					       pte_val(old_pte), pte_val(pte));
893 	} while (pte_val(pte) != pte_val(old_pte));
894 
895 	return pte_young(pte);
896 }
897 
898 static inline int ptep_test_and_clear_young(struct vm_area_struct *vma,
899 					    unsigned long address,
900 					    pte_t *ptep)
901 {
902 	return __ptep_test_and_clear_young(ptep);
903 }
904 
905 #define __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
906 static inline int ptep_clear_flush_young(struct vm_area_struct *vma,
907 					 unsigned long address, pte_t *ptep)
908 {
909 	int young = ptep_test_and_clear_young(vma, address, ptep);
910 
911 	if (young) {
912 		/*
913 		 * We can elide the trailing DSB here since the worst that can
914 		 * happen is that a CPU continues to use the young entry in its
915 		 * TLB and we mistakenly reclaim the associated page. The
916 		 * window for such an event is bounded by the next
917 		 * context-switch, which provides a DSB to complete the TLB
918 		 * invalidation.
919 		 */
920 		flush_tlb_page_nosync(vma, address);
921 	}
922 
923 	return young;
924 }
925 
926 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
927 #define __HAVE_ARCH_PMDP_TEST_AND_CLEAR_YOUNG
928 static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma,
929 					    unsigned long address,
930 					    pmd_t *pmdp)
931 {
932 	return ptep_test_and_clear_young(vma, address, (pte_t *)pmdp);
933 }
934 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
935 
936 #define __HAVE_ARCH_PTEP_GET_AND_CLEAR
937 static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
938 				       unsigned long address, pte_t *ptep)
939 {
940 	pte_t pte = __pte(xchg_relaxed(&pte_val(*ptep), 0));
941 
942 	page_table_check_pte_clear(mm, address, pte);
943 
944 	return pte;
945 }
946 
947 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
948 #define __HAVE_ARCH_PMDP_HUGE_GET_AND_CLEAR
949 static inline pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm,
950 					    unsigned long address, pmd_t *pmdp)
951 {
952 	pmd_t pmd = __pmd(xchg_relaxed(&pmd_val(*pmdp), 0));
953 
954 	page_table_check_pmd_clear(mm, address, pmd);
955 
956 	return pmd;
957 }
958 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
959 
960 /*
961  * ptep_set_wrprotect - mark read-only while trasferring potential hardware
962  * dirty status (PTE_DBM && !PTE_RDONLY) to the software PTE_DIRTY bit.
963  */
964 #define __HAVE_ARCH_PTEP_SET_WRPROTECT
965 static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long address, pte_t *ptep)
966 {
967 	pte_t old_pte, pte;
968 
969 	pte = READ_ONCE(*ptep);
970 	do {
971 		old_pte = pte;
972 		pte = pte_wrprotect(pte);
973 		pte_val(pte) = cmpxchg_relaxed(&pte_val(*ptep),
974 					       pte_val(old_pte), pte_val(pte));
975 	} while (pte_val(pte) != pte_val(old_pte));
976 }
977 
978 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
979 #define __HAVE_ARCH_PMDP_SET_WRPROTECT
980 static inline void pmdp_set_wrprotect(struct mm_struct *mm,
981 				      unsigned long address, pmd_t *pmdp)
982 {
983 	ptep_set_wrprotect(mm, address, (pte_t *)pmdp);
984 }
985 
986 #define pmdp_establish pmdp_establish
987 static inline pmd_t pmdp_establish(struct vm_area_struct *vma,
988 		unsigned long address, pmd_t *pmdp, pmd_t pmd)
989 {
990 	page_table_check_pmd_set(vma->vm_mm, address, pmdp, pmd);
991 	return __pmd(xchg_relaxed(&pmd_val(*pmdp), pmd_val(pmd)));
992 }
993 #endif
994 
995 /*
996  * Encode and decode a swap entry:
997  *	bits 0-1:	present (must be zero)
998  *	bits 2:		remember PG_anon_exclusive
999  *	bits 3-7:	swap type
1000  *	bits 8-57:	swap offset
1001  *	bit  58:	PTE_PROT_NONE (must be zero)
1002  */
1003 #define __SWP_TYPE_SHIFT	3
1004 #define __SWP_TYPE_BITS		5
1005 #define __SWP_OFFSET_BITS	50
1006 #define __SWP_TYPE_MASK		((1 << __SWP_TYPE_BITS) - 1)
1007 #define __SWP_OFFSET_SHIFT	(__SWP_TYPE_BITS + __SWP_TYPE_SHIFT)
1008 #define __SWP_OFFSET_MASK	((1UL << __SWP_OFFSET_BITS) - 1)
1009 
1010 #define __swp_type(x)		(((x).val >> __SWP_TYPE_SHIFT) & __SWP_TYPE_MASK)
1011 #define __swp_offset(x)		(((x).val >> __SWP_OFFSET_SHIFT) & __SWP_OFFSET_MASK)
1012 #define __swp_entry(type,offset) ((swp_entry_t) { ((type) << __SWP_TYPE_SHIFT) | ((offset) << __SWP_OFFSET_SHIFT) })
1013 
1014 #define __pte_to_swp_entry(pte)	((swp_entry_t) { pte_val(pte) })
1015 #define __swp_entry_to_pte(swp)	((pte_t) { (swp).val })
1016 
1017 #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION
1018 #define __pmd_to_swp_entry(pmd)		((swp_entry_t) { pmd_val(pmd) })
1019 #define __swp_entry_to_pmd(swp)		__pmd((swp).val)
1020 #endif /* CONFIG_ARCH_ENABLE_THP_MIGRATION */
1021 
1022 /*
1023  * Ensure that there are not more swap files than can be encoded in the kernel
1024  * PTEs.
1025  */
1026 #define MAX_SWAPFILES_CHECK() BUILD_BUG_ON(MAX_SWAPFILES_SHIFT > __SWP_TYPE_BITS)
1027 
1028 #ifdef CONFIG_ARM64_MTE
1029 
1030 #define __HAVE_ARCH_PREPARE_TO_SWAP
1031 static inline int arch_prepare_to_swap(struct page *page)
1032 {
1033 	if (system_supports_mte())
1034 		return mte_save_tags(page);
1035 	return 0;
1036 }
1037 
1038 #define __HAVE_ARCH_SWAP_INVALIDATE
1039 static inline void arch_swap_invalidate_page(int type, pgoff_t offset)
1040 {
1041 	if (system_supports_mte())
1042 		mte_invalidate_tags(type, offset);
1043 }
1044 
1045 static inline void arch_swap_invalidate_area(int type)
1046 {
1047 	if (system_supports_mte())
1048 		mte_invalidate_tags_area(type);
1049 }
1050 
1051 #define __HAVE_ARCH_SWAP_RESTORE
1052 static inline void arch_swap_restore(swp_entry_t entry, struct folio *folio)
1053 {
1054 	if (system_supports_mte())
1055 		mte_restore_tags(entry, &folio->page);
1056 }
1057 
1058 #endif /* CONFIG_ARM64_MTE */
1059 
1060 /*
1061  * On AArch64, the cache coherency is handled via the set_pte_at() function.
1062  */
1063 static inline void update_mmu_cache(struct vm_area_struct *vma,
1064 				    unsigned long addr, pte_t *ptep)
1065 {
1066 	/*
1067 	 * We don't do anything here, so there's a very small chance of
1068 	 * us retaking a user fault which we just fixed up. The alternative
1069 	 * is doing a dsb(ishst), but that penalises the fastpath.
1070 	 */
1071 }
1072 
1073 #define update_mmu_cache_pmd(vma, address, pmd) do { } while (0)
1074 
1075 #ifdef CONFIG_ARM64_PA_BITS_52
1076 #define phys_to_ttbr(addr)	(((addr) | ((addr) >> 46)) & TTBR_BADDR_MASK_52)
1077 #else
1078 #define phys_to_ttbr(addr)	(addr)
1079 #endif
1080 
1081 /*
1082  * On arm64 without hardware Access Flag, copying from user will fail because
1083  * the pte is old and cannot be marked young. So we always end up with zeroed
1084  * page after fork() + CoW for pfn mappings. We don't always have a
1085  * hardware-managed access flag on arm64.
1086  */
1087 #define arch_has_hw_pte_young		cpu_has_hw_af
1088 
1089 /*
1090  * Experimentally, it's cheap to set the access flag in hardware and we
1091  * benefit from prefaulting mappings as 'old' to start with.
1092  */
1093 #define arch_wants_old_prefaulted_pte	cpu_has_hw_af
1094 
1095 static inline bool pud_sect_supported(void)
1096 {
1097 	return PAGE_SIZE == SZ_4K;
1098 }
1099 
1100 
1101 #define __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION
1102 #define ptep_modify_prot_start ptep_modify_prot_start
1103 extern pte_t ptep_modify_prot_start(struct vm_area_struct *vma,
1104 				    unsigned long addr, pte_t *ptep);
1105 
1106 #define ptep_modify_prot_commit ptep_modify_prot_commit
1107 extern void ptep_modify_prot_commit(struct vm_area_struct *vma,
1108 				    unsigned long addr, pte_t *ptep,
1109 				    pte_t old_pte, pte_t new_pte);
1110 #endif /* !__ASSEMBLY__ */
1111 
1112 #endif /* __ASM_PGTABLE_H */
1113