xref: /openbmc/linux/arch/arm64/include/asm/pgtable.h (revision eb3fcf00)
1 /*
2  * Copyright (C) 2012 ARM Ltd.
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License version 2 as
6  * published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope that it will be useful,
9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
11  * GNU General Public License for more details.
12  *
13  * You should have received a copy of the GNU General Public License
14  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
15  */
16 #ifndef __ASM_PGTABLE_H
17 #define __ASM_PGTABLE_H
18 
19 #include <asm/bug.h>
20 #include <asm/proc-fns.h>
21 
22 #include <asm/memory.h>
23 #include <asm/pgtable-hwdef.h>
24 
25 /*
26  * Software defined PTE bits definition.
27  */
28 #define PTE_VALID		(_AT(pteval_t, 1) << 0)
29 #define PTE_WRITE		(PTE_DBM)		 /* same as DBM (51) */
30 #define PTE_DIRTY		(_AT(pteval_t, 1) << 55)
31 #define PTE_SPECIAL		(_AT(pteval_t, 1) << 56)
32 #define PTE_PROT_NONE		(_AT(pteval_t, 1) << 58) /* only when !PTE_VALID */
33 
34 /*
35  * VMALLOC and SPARSEMEM_VMEMMAP ranges.
36  *
37  * VMEMAP_SIZE: allows the whole VA space to be covered by a struct page array
38  *	(rounded up to PUD_SIZE).
39  * VMALLOC_START: beginning of the kernel VA space
40  * VMALLOC_END: extends to the available space below vmmemmap, PCI I/O space,
41  *	fixed mappings and modules
42  */
43 #define VMEMMAP_SIZE		ALIGN((1UL << (VA_BITS - PAGE_SHIFT)) * sizeof(struct page), PUD_SIZE)
44 #define VMALLOC_START		(UL(0xffffffffffffffff) << VA_BITS)
45 #define VMALLOC_END		(PAGE_OFFSET - PUD_SIZE - VMEMMAP_SIZE - SZ_64K)
46 
47 #define vmemmap			((struct page *)(VMALLOC_END + SZ_64K))
48 
49 #define FIRST_USER_ADDRESS	0UL
50 
51 #ifndef __ASSEMBLY__
52 
53 #include <linux/mmdebug.h>
54 
55 extern void __pte_error(const char *file, int line, unsigned long val);
56 extern void __pmd_error(const char *file, int line, unsigned long val);
57 extern void __pud_error(const char *file, int line, unsigned long val);
58 extern void __pgd_error(const char *file, int line, unsigned long val);
59 
60 #define PROT_DEFAULT		(PTE_TYPE_PAGE | PTE_AF | PTE_SHARED)
61 #define PROT_SECT_DEFAULT	(PMD_TYPE_SECT | PMD_SECT_AF | PMD_SECT_S)
62 
63 #define PROT_DEVICE_nGnRE	(PROT_DEFAULT | PTE_PXN | PTE_UXN | PTE_ATTRINDX(MT_DEVICE_nGnRE))
64 #define PROT_NORMAL_NC		(PROT_DEFAULT | PTE_PXN | PTE_UXN | PTE_ATTRINDX(MT_NORMAL_NC))
65 #define PROT_NORMAL		(PROT_DEFAULT | PTE_PXN | PTE_UXN | PTE_ATTRINDX(MT_NORMAL))
66 
67 #define PROT_SECT_DEVICE_nGnRE	(PROT_SECT_DEFAULT | PMD_SECT_PXN | PMD_SECT_UXN | PMD_ATTRINDX(MT_DEVICE_nGnRE))
68 #define PROT_SECT_NORMAL	(PROT_SECT_DEFAULT | PMD_SECT_PXN | PMD_SECT_UXN | PMD_ATTRINDX(MT_NORMAL))
69 #define PROT_SECT_NORMAL_EXEC	(PROT_SECT_DEFAULT | PMD_SECT_UXN | PMD_ATTRINDX(MT_NORMAL))
70 
71 #define _PAGE_DEFAULT		(PROT_DEFAULT | PTE_ATTRINDX(MT_NORMAL))
72 
73 #define PAGE_KERNEL		__pgprot(_PAGE_DEFAULT | PTE_PXN | PTE_UXN | PTE_DIRTY | PTE_WRITE)
74 #define PAGE_KERNEL_EXEC	__pgprot(_PAGE_DEFAULT | PTE_UXN | PTE_DIRTY | PTE_WRITE)
75 
76 #define PAGE_HYP		__pgprot(_PAGE_DEFAULT | PTE_HYP)
77 #define PAGE_HYP_DEVICE		__pgprot(PROT_DEVICE_nGnRE | PTE_HYP)
78 
79 #define PAGE_S2			__pgprot(PROT_DEFAULT | PTE_S2_MEMATTR(MT_S2_NORMAL) | PTE_S2_RDONLY)
80 #define PAGE_S2_DEVICE		__pgprot(PROT_DEFAULT | PTE_S2_MEMATTR(MT_S2_DEVICE_nGnRE) | PTE_S2_RDONLY | PTE_UXN)
81 
82 #define PAGE_NONE		__pgprot(((_PAGE_DEFAULT) & ~PTE_TYPE_MASK) | PTE_PROT_NONE | PTE_PXN | PTE_UXN)
83 #define PAGE_SHARED		__pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN | PTE_UXN | PTE_WRITE)
84 #define PAGE_SHARED_EXEC	__pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN | PTE_WRITE)
85 #define PAGE_COPY		__pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN | PTE_UXN)
86 #define PAGE_COPY_EXEC		__pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN)
87 #define PAGE_READONLY		__pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN | PTE_UXN)
88 #define PAGE_READONLY_EXEC	__pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN)
89 
90 #define __P000  PAGE_NONE
91 #define __P001  PAGE_READONLY
92 #define __P010  PAGE_COPY
93 #define __P011  PAGE_COPY
94 #define __P100  PAGE_READONLY_EXEC
95 #define __P101  PAGE_READONLY_EXEC
96 #define __P110  PAGE_COPY_EXEC
97 #define __P111  PAGE_COPY_EXEC
98 
99 #define __S000  PAGE_NONE
100 #define __S001  PAGE_READONLY
101 #define __S010  PAGE_SHARED
102 #define __S011  PAGE_SHARED
103 #define __S100  PAGE_READONLY_EXEC
104 #define __S101  PAGE_READONLY_EXEC
105 #define __S110  PAGE_SHARED_EXEC
106 #define __S111  PAGE_SHARED_EXEC
107 
108 /*
109  * ZERO_PAGE is a global shared page that is always zero: used
110  * for zero-mapped memory areas etc..
111  */
112 extern struct page *empty_zero_page;
113 #define ZERO_PAGE(vaddr)	(empty_zero_page)
114 
115 #define pte_ERROR(pte)		__pte_error(__FILE__, __LINE__, pte_val(pte))
116 
117 #define pte_pfn(pte)		((pte_val(pte) & PHYS_MASK) >> PAGE_SHIFT)
118 
119 #define pfn_pte(pfn,prot)	(__pte(((phys_addr_t)(pfn) << PAGE_SHIFT) | pgprot_val(prot)))
120 
121 #define pte_none(pte)		(!pte_val(pte))
122 #define pte_clear(mm,addr,ptep)	set_pte(ptep, __pte(0))
123 #define pte_page(pte)		(pfn_to_page(pte_pfn(pte)))
124 
125 /* Find an entry in the third-level page table. */
126 #define pte_index(addr)		(((addr) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
127 
128 #define pte_offset_kernel(dir,addr)	(pmd_page_vaddr(*(dir)) + pte_index(addr))
129 
130 #define pte_offset_map(dir,addr)	pte_offset_kernel((dir), (addr))
131 #define pte_offset_map_nested(dir,addr)	pte_offset_kernel((dir), (addr))
132 #define pte_unmap(pte)			do { } while (0)
133 #define pte_unmap_nested(pte)		do { } while (0)
134 
135 /*
136  * The following only work if pte_present(). Undefined behaviour otherwise.
137  */
138 #define pte_present(pte)	(!!(pte_val(pte) & (PTE_VALID | PTE_PROT_NONE)))
139 #define pte_young(pte)		(!!(pte_val(pte) & PTE_AF))
140 #define pte_special(pte)	(!!(pte_val(pte) & PTE_SPECIAL))
141 #define pte_write(pte)		(!!(pte_val(pte) & PTE_WRITE))
142 #define pte_exec(pte)		(!(pte_val(pte) & PTE_UXN))
143 
144 #ifdef CONFIG_ARM64_HW_AFDBM
145 #define pte_hw_dirty(pte)	(pte_write(pte) && !(pte_val(pte) & PTE_RDONLY))
146 #else
147 #define pte_hw_dirty(pte)	(0)
148 #endif
149 #define pte_sw_dirty(pte)	(!!(pte_val(pte) & PTE_DIRTY))
150 #define pte_dirty(pte)		(pte_sw_dirty(pte) || pte_hw_dirty(pte))
151 
152 #define pte_valid(pte)		(!!(pte_val(pte) & PTE_VALID))
153 #define pte_valid_user(pte) \
154 	((pte_val(pte) & (PTE_VALID | PTE_USER)) == (PTE_VALID | PTE_USER))
155 #define pte_valid_not_user(pte) \
156 	((pte_val(pte) & (PTE_VALID | PTE_USER)) == PTE_VALID)
157 
158 static inline pte_t clear_pte_bit(pte_t pte, pgprot_t prot)
159 {
160 	pte_val(pte) &= ~pgprot_val(prot);
161 	return pte;
162 }
163 
164 static inline pte_t set_pte_bit(pte_t pte, pgprot_t prot)
165 {
166 	pte_val(pte) |= pgprot_val(prot);
167 	return pte;
168 }
169 
170 static inline pte_t pte_wrprotect(pte_t pte)
171 {
172 	return clear_pte_bit(pte, __pgprot(PTE_WRITE));
173 }
174 
175 static inline pte_t pte_mkwrite(pte_t pte)
176 {
177 	return set_pte_bit(pte, __pgprot(PTE_WRITE));
178 }
179 
180 static inline pte_t pte_mkclean(pte_t pte)
181 {
182 	return clear_pte_bit(pte, __pgprot(PTE_DIRTY));
183 }
184 
185 static inline pte_t pte_mkdirty(pte_t pte)
186 {
187 	return set_pte_bit(pte, __pgprot(PTE_DIRTY));
188 }
189 
190 static inline pte_t pte_mkold(pte_t pte)
191 {
192 	return clear_pte_bit(pte, __pgprot(PTE_AF));
193 }
194 
195 static inline pte_t pte_mkyoung(pte_t pte)
196 {
197 	return set_pte_bit(pte, __pgprot(PTE_AF));
198 }
199 
200 static inline pte_t pte_mkspecial(pte_t pte)
201 {
202 	return set_pte_bit(pte, __pgprot(PTE_SPECIAL));
203 }
204 
205 static inline void set_pte(pte_t *ptep, pte_t pte)
206 {
207 	*ptep = pte;
208 
209 	/*
210 	 * Only if the new pte is valid and kernel, otherwise TLB maintenance
211 	 * or update_mmu_cache() have the necessary barriers.
212 	 */
213 	if (pte_valid_not_user(pte)) {
214 		dsb(ishst);
215 		isb();
216 	}
217 }
218 
219 struct mm_struct;
220 struct vm_area_struct;
221 
222 extern void __sync_icache_dcache(pte_t pteval, unsigned long addr);
223 
224 /*
225  * PTE bits configuration in the presence of hardware Dirty Bit Management
226  * (PTE_WRITE == PTE_DBM):
227  *
228  * Dirty  Writable | PTE_RDONLY  PTE_WRITE  PTE_DIRTY (sw)
229  *   0      0      |   1           0          0
230  *   0      1      |   1           1          0
231  *   1      0      |   1           0          1
232  *   1      1      |   0           1          x
233  *
234  * When hardware DBM is not present, the sofware PTE_DIRTY bit is updated via
235  * the page fault mechanism. Checking the dirty status of a pte becomes:
236  *
237  *   PTE_DIRTY || (PTE_WRITE && !PTE_RDONLY)
238  */
239 static inline void set_pte_at(struct mm_struct *mm, unsigned long addr,
240 			      pte_t *ptep, pte_t pte)
241 {
242 	if (pte_valid_user(pte)) {
243 		if (!pte_special(pte) && pte_exec(pte))
244 			__sync_icache_dcache(pte, addr);
245 		if (pte_sw_dirty(pte) && pte_write(pte))
246 			pte_val(pte) &= ~PTE_RDONLY;
247 		else
248 			pte_val(pte) |= PTE_RDONLY;
249 	}
250 
251 	/*
252 	 * If the existing pte is valid, check for potential race with
253 	 * hardware updates of the pte (ptep_set_access_flags safely changes
254 	 * valid ptes without going through an invalid entry).
255 	 */
256 	if (IS_ENABLED(CONFIG_DEBUG_VM) && IS_ENABLED(CONFIG_ARM64_HW_AFDBM) &&
257 	    pte_valid(*ptep)) {
258 		BUG_ON(!pte_young(pte));
259 		BUG_ON(pte_write(*ptep) && !pte_dirty(pte));
260 	}
261 
262 	set_pte(ptep, pte);
263 }
264 
265 /*
266  * Huge pte definitions.
267  */
268 #define pte_huge(pte)		(!(pte_val(pte) & PTE_TABLE_BIT))
269 #define pte_mkhuge(pte)		(__pte(pte_val(pte) & ~PTE_TABLE_BIT))
270 
271 /*
272  * Hugetlb definitions.
273  */
274 #define HUGE_MAX_HSTATE		2
275 #define HPAGE_SHIFT		PMD_SHIFT
276 #define HPAGE_SIZE		(_AC(1, UL) << HPAGE_SHIFT)
277 #define HPAGE_MASK		(~(HPAGE_SIZE - 1))
278 #define HUGETLB_PAGE_ORDER	(HPAGE_SHIFT - PAGE_SHIFT)
279 
280 #define __HAVE_ARCH_PTE_SPECIAL
281 
282 static inline pte_t pud_pte(pud_t pud)
283 {
284 	return __pte(pud_val(pud));
285 }
286 
287 static inline pmd_t pud_pmd(pud_t pud)
288 {
289 	return __pmd(pud_val(pud));
290 }
291 
292 static inline pte_t pmd_pte(pmd_t pmd)
293 {
294 	return __pte(pmd_val(pmd));
295 }
296 
297 static inline pmd_t pte_pmd(pte_t pte)
298 {
299 	return __pmd(pte_val(pte));
300 }
301 
302 static inline pgprot_t mk_sect_prot(pgprot_t prot)
303 {
304 	return __pgprot(pgprot_val(prot) & ~PTE_TABLE_BIT);
305 }
306 
307 /*
308  * THP definitions.
309  */
310 
311 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
312 #define pmd_trans_huge(pmd)	(pmd_val(pmd) && !(pmd_val(pmd) & PMD_TABLE_BIT))
313 #define pmd_trans_splitting(pmd)	pte_special(pmd_pte(pmd))
314 #ifdef CONFIG_HAVE_RCU_TABLE_FREE
315 #define __HAVE_ARCH_PMDP_SPLITTING_FLUSH
316 struct vm_area_struct;
317 void pmdp_splitting_flush(struct vm_area_struct *vma, unsigned long address,
318 			  pmd_t *pmdp);
319 #endif /* CONFIG_HAVE_RCU_TABLE_FREE */
320 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
321 
322 #define pmd_dirty(pmd)		pte_dirty(pmd_pte(pmd))
323 #define pmd_young(pmd)		pte_young(pmd_pte(pmd))
324 #define pmd_wrprotect(pmd)	pte_pmd(pte_wrprotect(pmd_pte(pmd)))
325 #define pmd_mksplitting(pmd)	pte_pmd(pte_mkspecial(pmd_pte(pmd)))
326 #define pmd_mkold(pmd)		pte_pmd(pte_mkold(pmd_pte(pmd)))
327 #define pmd_mkwrite(pmd)	pte_pmd(pte_mkwrite(pmd_pte(pmd)))
328 #define pmd_mkdirty(pmd)	pte_pmd(pte_mkdirty(pmd_pte(pmd)))
329 #define pmd_mkyoung(pmd)	pte_pmd(pte_mkyoung(pmd_pte(pmd)))
330 #define pmd_mknotpresent(pmd)	(__pmd(pmd_val(pmd) & ~PMD_TYPE_MASK))
331 
332 #define __HAVE_ARCH_PMD_WRITE
333 #define pmd_write(pmd)		pte_write(pmd_pte(pmd))
334 
335 #define pmd_mkhuge(pmd)		(__pmd(pmd_val(pmd) & ~PMD_TABLE_BIT))
336 
337 #define pmd_pfn(pmd)		(((pmd_val(pmd) & PMD_MASK) & PHYS_MASK) >> PAGE_SHIFT)
338 #define pfn_pmd(pfn,prot)	(__pmd(((phys_addr_t)(pfn) << PAGE_SHIFT) | pgprot_val(prot)))
339 #define mk_pmd(page,prot)	pfn_pmd(page_to_pfn(page),prot)
340 
341 #define pud_write(pud)		pte_write(pud_pte(pud))
342 #define pud_pfn(pud)		(((pud_val(pud) & PUD_MASK) & PHYS_MASK) >> PAGE_SHIFT)
343 
344 #define set_pmd_at(mm, addr, pmdp, pmd)	set_pte_at(mm, addr, (pte_t *)pmdp, pmd_pte(pmd))
345 
346 static inline int has_transparent_hugepage(void)
347 {
348 	return 1;
349 }
350 
351 #define __pgprot_modify(prot,mask,bits) \
352 	__pgprot((pgprot_val(prot) & ~(mask)) | (bits))
353 
354 /*
355  * Mark the prot value as uncacheable and unbufferable.
356  */
357 #define pgprot_noncached(prot) \
358 	__pgprot_modify(prot, PTE_ATTRINDX_MASK, PTE_ATTRINDX(MT_DEVICE_nGnRnE) | PTE_PXN | PTE_UXN)
359 #define pgprot_writecombine(prot) \
360 	__pgprot_modify(prot, PTE_ATTRINDX_MASK, PTE_ATTRINDX(MT_NORMAL_NC) | PTE_PXN | PTE_UXN)
361 #define pgprot_device(prot) \
362 	__pgprot_modify(prot, PTE_ATTRINDX_MASK, PTE_ATTRINDX(MT_DEVICE_nGnRE) | PTE_PXN | PTE_UXN)
363 #define __HAVE_PHYS_MEM_ACCESS_PROT
364 struct file;
365 extern pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
366 				     unsigned long size, pgprot_t vma_prot);
367 
368 #define pmd_none(pmd)		(!pmd_val(pmd))
369 #define pmd_present(pmd)	(pmd_val(pmd))
370 
371 #define pmd_bad(pmd)		(!(pmd_val(pmd) & 2))
372 
373 #define pmd_table(pmd)		((pmd_val(pmd) & PMD_TYPE_MASK) == \
374 				 PMD_TYPE_TABLE)
375 #define pmd_sect(pmd)		((pmd_val(pmd) & PMD_TYPE_MASK) == \
376 				 PMD_TYPE_SECT)
377 
378 #ifdef CONFIG_ARM64_64K_PAGES
379 #define pud_sect(pud)		(0)
380 #define pud_table(pud)		(1)
381 #else
382 #define pud_sect(pud)		((pud_val(pud) & PUD_TYPE_MASK) == \
383 				 PUD_TYPE_SECT)
384 #define pud_table(pud)		((pud_val(pud) & PUD_TYPE_MASK) == \
385 				 PUD_TYPE_TABLE)
386 #endif
387 
388 static inline void set_pmd(pmd_t *pmdp, pmd_t pmd)
389 {
390 	*pmdp = pmd;
391 	dsb(ishst);
392 	isb();
393 }
394 
395 static inline void pmd_clear(pmd_t *pmdp)
396 {
397 	set_pmd(pmdp, __pmd(0));
398 }
399 
400 static inline pte_t *pmd_page_vaddr(pmd_t pmd)
401 {
402 	return __va(pmd_val(pmd) & PHYS_MASK & (s32)PAGE_MASK);
403 }
404 
405 #define pmd_page(pmd)		pfn_to_page(__phys_to_pfn(pmd_val(pmd) & PHYS_MASK))
406 
407 /*
408  * Conversion functions: convert a page and protection to a page entry,
409  * and a page entry and page directory to the page they refer to.
410  */
411 #define mk_pte(page,prot)	pfn_pte(page_to_pfn(page),prot)
412 
413 #if CONFIG_PGTABLE_LEVELS > 2
414 
415 #define pmd_ERROR(pmd)		__pmd_error(__FILE__, __LINE__, pmd_val(pmd))
416 
417 #define pud_none(pud)		(!pud_val(pud))
418 #define pud_bad(pud)		(!(pud_val(pud) & 2))
419 #define pud_present(pud)	(pud_val(pud))
420 
421 static inline void set_pud(pud_t *pudp, pud_t pud)
422 {
423 	*pudp = pud;
424 	dsb(ishst);
425 	isb();
426 }
427 
428 static inline void pud_clear(pud_t *pudp)
429 {
430 	set_pud(pudp, __pud(0));
431 }
432 
433 static inline pmd_t *pud_page_vaddr(pud_t pud)
434 {
435 	return __va(pud_val(pud) & PHYS_MASK & (s32)PAGE_MASK);
436 }
437 
438 /* Find an entry in the second-level page table. */
439 #define pmd_index(addr)		(((addr) >> PMD_SHIFT) & (PTRS_PER_PMD - 1))
440 
441 static inline pmd_t *pmd_offset(pud_t *pud, unsigned long addr)
442 {
443 	return (pmd_t *)pud_page_vaddr(*pud) + pmd_index(addr);
444 }
445 
446 #define pud_page(pud)		pfn_to_page(__phys_to_pfn(pud_val(pud) & PHYS_MASK))
447 
448 #endif	/* CONFIG_PGTABLE_LEVELS > 2 */
449 
450 #if CONFIG_PGTABLE_LEVELS > 3
451 
452 #define pud_ERROR(pud)		__pud_error(__FILE__, __LINE__, pud_val(pud))
453 
454 #define pgd_none(pgd)		(!pgd_val(pgd))
455 #define pgd_bad(pgd)		(!(pgd_val(pgd) & 2))
456 #define pgd_present(pgd)	(pgd_val(pgd))
457 
458 static inline void set_pgd(pgd_t *pgdp, pgd_t pgd)
459 {
460 	*pgdp = pgd;
461 	dsb(ishst);
462 }
463 
464 static inline void pgd_clear(pgd_t *pgdp)
465 {
466 	set_pgd(pgdp, __pgd(0));
467 }
468 
469 static inline pud_t *pgd_page_vaddr(pgd_t pgd)
470 {
471 	return __va(pgd_val(pgd) & PHYS_MASK & (s32)PAGE_MASK);
472 }
473 
474 /* Find an entry in the frst-level page table. */
475 #define pud_index(addr)		(((addr) >> PUD_SHIFT) & (PTRS_PER_PUD - 1))
476 
477 static inline pud_t *pud_offset(pgd_t *pgd, unsigned long addr)
478 {
479 	return (pud_t *)pgd_page_vaddr(*pgd) + pud_index(addr);
480 }
481 
482 #define pgd_page(pgd)		pfn_to_page(__phys_to_pfn(pgd_val(pgd) & PHYS_MASK))
483 
484 #endif  /* CONFIG_PGTABLE_LEVELS > 3 */
485 
486 #define pgd_ERROR(pgd)		__pgd_error(__FILE__, __LINE__, pgd_val(pgd))
487 
488 /* to find an entry in a page-table-directory */
489 #define pgd_index(addr)		(((addr) >> PGDIR_SHIFT) & (PTRS_PER_PGD - 1))
490 
491 #define pgd_offset(mm, addr)	((mm)->pgd+pgd_index(addr))
492 
493 /* to find an entry in a kernel page-table-directory */
494 #define pgd_offset_k(addr)	pgd_offset(&init_mm, addr)
495 
496 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
497 {
498 	const pteval_t mask = PTE_USER | PTE_PXN | PTE_UXN | PTE_RDONLY |
499 			      PTE_PROT_NONE | PTE_WRITE | PTE_TYPE_MASK;
500 	/* preserve the hardware dirty information */
501 	if (pte_hw_dirty(pte))
502 		pte = pte_mkdirty(pte);
503 	pte_val(pte) = (pte_val(pte) & ~mask) | (pgprot_val(newprot) & mask);
504 	return pte;
505 }
506 
507 static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot)
508 {
509 	return pte_pmd(pte_modify(pmd_pte(pmd), newprot));
510 }
511 
512 #ifdef CONFIG_ARM64_HW_AFDBM
513 /*
514  * Atomic pte/pmd modifications.
515  */
516 #define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
517 static inline int ptep_test_and_clear_young(struct vm_area_struct *vma,
518 					    unsigned long address,
519 					    pte_t *ptep)
520 {
521 	pteval_t pteval;
522 	unsigned int tmp, res;
523 
524 	asm volatile("//	ptep_test_and_clear_young\n"
525 	"	prfm	pstl1strm, %2\n"
526 	"1:	ldxr	%0, %2\n"
527 	"	ubfx	%w3, %w0, %5, #1	// extract PTE_AF (young)\n"
528 	"	and	%0, %0, %4		// clear PTE_AF\n"
529 	"	stxr	%w1, %0, %2\n"
530 	"	cbnz	%w1, 1b\n"
531 	: "=&r" (pteval), "=&r" (tmp), "+Q" (pte_val(*ptep)), "=&r" (res)
532 	: "L" (~PTE_AF), "I" (ilog2(PTE_AF)));
533 
534 	return res;
535 }
536 
537 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
538 #define __HAVE_ARCH_PMDP_TEST_AND_CLEAR_YOUNG
539 static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma,
540 					    unsigned long address,
541 					    pmd_t *pmdp)
542 {
543 	return ptep_test_and_clear_young(vma, address, (pte_t *)pmdp);
544 }
545 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
546 
547 #define __HAVE_ARCH_PTEP_GET_AND_CLEAR
548 static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
549 				       unsigned long address, pte_t *ptep)
550 {
551 	pteval_t old_pteval;
552 	unsigned int tmp;
553 
554 	asm volatile("//	ptep_get_and_clear\n"
555 	"	prfm	pstl1strm, %2\n"
556 	"1:	ldxr	%0, %2\n"
557 	"	stxr	%w1, xzr, %2\n"
558 	"	cbnz	%w1, 1b\n"
559 	: "=&r" (old_pteval), "=&r" (tmp), "+Q" (pte_val(*ptep)));
560 
561 	return __pte(old_pteval);
562 }
563 
564 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
565 #define __HAVE_ARCH_PMDP_GET_AND_CLEAR
566 static inline pmd_t pmdp_get_and_clear(struct mm_struct *mm,
567 				       unsigned long address, pmd_t *pmdp)
568 {
569 	return pte_pmd(ptep_get_and_clear(mm, address, (pte_t *)pmdp));
570 }
571 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
572 
573 /*
574  * ptep_set_wrprotect - mark read-only while trasferring potential hardware
575  * dirty status (PTE_DBM && !PTE_RDONLY) to the software PTE_DIRTY bit.
576  */
577 #define __HAVE_ARCH_PTEP_SET_WRPROTECT
578 static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long address, pte_t *ptep)
579 {
580 	pteval_t pteval;
581 	unsigned long tmp;
582 
583 	asm volatile("//	ptep_set_wrprotect\n"
584 	"	prfm	pstl1strm, %2\n"
585 	"1:	ldxr	%0, %2\n"
586 	"	tst	%0, %4			// check for hw dirty (!PTE_RDONLY)\n"
587 	"	csel	%1, %3, xzr, eq		// set PTE_DIRTY|PTE_RDONLY if dirty\n"
588 	"	orr	%0, %0, %1		// if !dirty, PTE_RDONLY is already set\n"
589 	"	and	%0, %0, %5		// clear PTE_WRITE/PTE_DBM\n"
590 	"	stxr	%w1, %0, %2\n"
591 	"	cbnz	%w1, 1b\n"
592 	: "=&r" (pteval), "=&r" (tmp), "+Q" (pte_val(*ptep))
593 	: "r" (PTE_DIRTY|PTE_RDONLY), "L" (PTE_RDONLY), "L" (~PTE_WRITE)
594 	: "cc");
595 }
596 
597 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
598 #define __HAVE_ARCH_PMDP_SET_WRPROTECT
599 static inline void pmdp_set_wrprotect(struct mm_struct *mm,
600 				      unsigned long address, pmd_t *pmdp)
601 {
602 	ptep_set_wrprotect(mm, address, (pte_t *)pmdp);
603 }
604 #endif
605 #endif	/* CONFIG_ARM64_HW_AFDBM */
606 
607 extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
608 extern pgd_t idmap_pg_dir[PTRS_PER_PGD];
609 
610 /*
611  * Encode and decode a swap entry:
612  *	bits 0-1:	present (must be zero)
613  *	bits 2-7:	swap type
614  *	bits 8-57:	swap offset
615  */
616 #define __SWP_TYPE_SHIFT	2
617 #define __SWP_TYPE_BITS		6
618 #define __SWP_OFFSET_BITS	50
619 #define __SWP_TYPE_MASK		((1 << __SWP_TYPE_BITS) - 1)
620 #define __SWP_OFFSET_SHIFT	(__SWP_TYPE_BITS + __SWP_TYPE_SHIFT)
621 #define __SWP_OFFSET_MASK	((1UL << __SWP_OFFSET_BITS) - 1)
622 
623 #define __swp_type(x)		(((x).val >> __SWP_TYPE_SHIFT) & __SWP_TYPE_MASK)
624 #define __swp_offset(x)		(((x).val >> __SWP_OFFSET_SHIFT) & __SWP_OFFSET_MASK)
625 #define __swp_entry(type,offset) ((swp_entry_t) { ((type) << __SWP_TYPE_SHIFT) | ((offset) << __SWP_OFFSET_SHIFT) })
626 
627 #define __pte_to_swp_entry(pte)	((swp_entry_t) { pte_val(pte) })
628 #define __swp_entry_to_pte(swp)	((pte_t) { (swp).val })
629 
630 /*
631  * Ensure that there are not more swap files than can be encoded in the kernel
632  * PTEs.
633  */
634 #define MAX_SWAPFILES_CHECK() BUILD_BUG_ON(MAX_SWAPFILES_SHIFT > __SWP_TYPE_BITS)
635 
636 extern int kern_addr_valid(unsigned long addr);
637 
638 #include <asm-generic/pgtable.h>
639 
640 #define pgtable_cache_init() do { } while (0)
641 
642 /*
643  * On AArch64, the cache coherency is handled via the set_pte_at() function.
644  */
645 static inline void update_mmu_cache(struct vm_area_struct *vma,
646 				    unsigned long addr, pte_t *ptep)
647 {
648 	/*
649 	 * set_pte() does not have a DSB for user mappings, so make sure that
650 	 * the page table write is visible.
651 	 */
652 	dsb(ishst);
653 }
654 
655 #define update_mmu_cache_pmd(vma, address, pmd) do { } while (0)
656 
657 #endif /* !__ASSEMBLY__ */
658 
659 #endif /* __ASM_PGTABLE_H */
660