xref: /openbmc/linux/arch/riscv/include/asm/pgtable.h (revision 887069f4)
1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  * Copyright (C) 2012 Regents of the University of California
4  */
5 
6 #ifndef _ASM_RISCV_PGTABLE_H
7 #define _ASM_RISCV_PGTABLE_H
8 
9 #include <linux/mmzone.h>
10 #include <linux/sizes.h>
11 
12 #include <asm/pgtable-bits.h>
13 
14 #ifndef CONFIG_MMU
15 #define KERNEL_LINK_ADDR	PAGE_OFFSET
16 #else
17 
18 #define ADDRESS_SPACE_END	(UL(-1))
19 
20 #ifdef CONFIG_64BIT
21 /* Leave 2GB for kernel and BPF at the end of the address space */
22 #define KERNEL_LINK_ADDR	(ADDRESS_SPACE_END - SZ_2G + 1)
23 #else
24 #define KERNEL_LINK_ADDR	PAGE_OFFSET
25 #endif
26 
27 #define VMALLOC_SIZE     (KERN_VIRT_SIZE >> 1)
28 #define VMALLOC_END      (PAGE_OFFSET - 1)
29 #define VMALLOC_START    (PAGE_OFFSET - VMALLOC_SIZE)
30 
31 #define BPF_JIT_REGION_SIZE	(SZ_128M)
32 #ifdef CONFIG_64BIT
33 #define BPF_JIT_REGION_START	(BPF_JIT_REGION_END - BPF_JIT_REGION_SIZE)
34 #define BPF_JIT_REGION_END	(MODULES_END)
35 #else
36 #define BPF_JIT_REGION_START	(PAGE_OFFSET - BPF_JIT_REGION_SIZE)
37 #define BPF_JIT_REGION_END	(VMALLOC_END)
38 #endif
39 
40 /* Modules always live before the kernel */
41 #ifdef CONFIG_64BIT
42 #define MODULES_VADDR	(PFN_ALIGN((unsigned long)&_end) - SZ_2G)
43 #define MODULES_END	(PFN_ALIGN((unsigned long)&_start))
44 #endif
45 
46 /*
47  * Roughly size the vmemmap space to be large enough to fit enough
48  * struct pages to map half the virtual address space. Then
49  * position vmemmap directly below the VMALLOC region.
50  */
51 #define VMEMMAP_SHIFT \
52 	(CONFIG_VA_BITS - PAGE_SHIFT - 1 + STRUCT_PAGE_MAX_SHIFT)
53 #define VMEMMAP_SIZE	BIT(VMEMMAP_SHIFT)
54 #define VMEMMAP_END	(VMALLOC_START - 1)
55 #define VMEMMAP_START	(VMALLOC_START - VMEMMAP_SIZE)
56 
57 /*
58  * Define vmemmap for pfn_to_page & page_to_pfn calls. Needed if kernel
59  * is configured with CONFIG_SPARSEMEM_VMEMMAP enabled.
60  */
61 #define vmemmap		((struct page *)VMEMMAP_START)
62 
63 #define PCI_IO_SIZE      SZ_16M
64 #define PCI_IO_END       VMEMMAP_START
65 #define PCI_IO_START     (PCI_IO_END - PCI_IO_SIZE)
66 
67 #define FIXADDR_TOP      PCI_IO_START
68 #ifdef CONFIG_64BIT
69 #define FIXADDR_SIZE     PMD_SIZE
70 #else
71 #define FIXADDR_SIZE     PGDIR_SIZE
72 #endif
73 #define FIXADDR_START    (FIXADDR_TOP - FIXADDR_SIZE)
74 
75 #endif
76 
77 #ifdef CONFIG_XIP_KERNEL
78 #define XIP_OFFSET		SZ_8M
79 #else
80 #define XIP_OFFSET		0
81 #endif
82 
83 #ifndef __ASSEMBLY__
84 
85 /* Page Upper Directory not used in RISC-V */
86 #include <asm-generic/pgtable-nopud.h>
87 #include <asm/page.h>
88 #include <asm/tlbflush.h>
89 #include <linux/mm_types.h>
90 
91 #ifdef CONFIG_64BIT
92 #include <asm/pgtable-64.h>
93 #else
94 #include <asm/pgtable-32.h>
95 #endif /* CONFIG_64BIT */
96 
97 #ifdef CONFIG_XIP_KERNEL
98 #define XIP_FIXUP(addr) ({							\
99 	uintptr_t __a = (uintptr_t)(addr);					\
100 	(__a >= CONFIG_XIP_PHYS_ADDR && __a < CONFIG_XIP_PHYS_ADDR + SZ_16M) ?	\
101 		__a - CONFIG_XIP_PHYS_ADDR + CONFIG_PHYS_RAM_BASE - XIP_OFFSET :\
102 		__a;								\
103 	})
104 #else
105 #define XIP_FIXUP(addr)		(addr)
106 #endif /* CONFIG_XIP_KERNEL */
107 
108 #ifdef CONFIG_MMU
109 /* Number of entries in the page global directory */
110 #define PTRS_PER_PGD    (PAGE_SIZE / sizeof(pgd_t))
111 /* Number of entries in the page table */
112 #define PTRS_PER_PTE    (PAGE_SIZE / sizeof(pte_t))
113 
114 /* Number of PGD entries that a user-mode program can use */
115 #define USER_PTRS_PER_PGD   (TASK_SIZE / PGDIR_SIZE)
116 
117 /* Page protection bits */
118 #define _PAGE_BASE	(_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_USER)
119 
120 #define PAGE_NONE		__pgprot(_PAGE_PROT_NONE)
121 #define PAGE_READ		__pgprot(_PAGE_BASE | _PAGE_READ)
122 #define PAGE_WRITE		__pgprot(_PAGE_BASE | _PAGE_READ | _PAGE_WRITE)
123 #define PAGE_EXEC		__pgprot(_PAGE_BASE | _PAGE_EXEC)
124 #define PAGE_READ_EXEC		__pgprot(_PAGE_BASE | _PAGE_READ | _PAGE_EXEC)
125 #define PAGE_WRITE_EXEC		__pgprot(_PAGE_BASE | _PAGE_READ |	\
126 					 _PAGE_EXEC | _PAGE_WRITE)
127 
128 #define PAGE_COPY		PAGE_READ
129 #define PAGE_COPY_EXEC		PAGE_EXEC
130 #define PAGE_COPY_READ_EXEC	PAGE_READ_EXEC
131 #define PAGE_SHARED		PAGE_WRITE
132 #define PAGE_SHARED_EXEC	PAGE_WRITE_EXEC
133 
134 #define _PAGE_KERNEL		(_PAGE_READ \
135 				| _PAGE_WRITE \
136 				| _PAGE_PRESENT \
137 				| _PAGE_ACCESSED \
138 				| _PAGE_DIRTY \
139 				| _PAGE_GLOBAL)
140 
141 #define PAGE_KERNEL		__pgprot(_PAGE_KERNEL)
142 #define PAGE_KERNEL_READ	__pgprot(_PAGE_KERNEL & ~_PAGE_WRITE)
143 #define PAGE_KERNEL_EXEC	__pgprot(_PAGE_KERNEL | _PAGE_EXEC)
144 #define PAGE_KERNEL_READ_EXEC	__pgprot((_PAGE_KERNEL & ~_PAGE_WRITE) \
145 					 | _PAGE_EXEC)
146 
147 #define PAGE_TABLE		__pgprot(_PAGE_TABLE)
148 
149 /*
150  * The RISC-V ISA doesn't yet specify how to query or modify PMAs, so we can't
151  * change the properties of memory regions.
152  */
153 #define _PAGE_IOREMAP _PAGE_KERNEL
154 
155 extern pgd_t swapper_pg_dir[];
156 
157 /* MAP_PRIVATE permissions: xwr (copy-on-write) */
158 #define __P000	PAGE_NONE
159 #define __P001	PAGE_READ
160 #define __P010	PAGE_COPY
161 #define __P011	PAGE_COPY
162 #define __P100	PAGE_EXEC
163 #define __P101	PAGE_READ_EXEC
164 #define __P110	PAGE_COPY_EXEC
165 #define __P111	PAGE_COPY_READ_EXEC
166 
167 /* MAP_SHARED permissions: xwr */
168 #define __S000	PAGE_NONE
169 #define __S001	PAGE_READ
170 #define __S010	PAGE_SHARED
171 #define __S011	PAGE_SHARED
172 #define __S100	PAGE_EXEC
173 #define __S101	PAGE_READ_EXEC
174 #define __S110	PAGE_SHARED_EXEC
175 #define __S111	PAGE_SHARED_EXEC
176 
177 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
178 static inline int pmd_present(pmd_t pmd)
179 {
180 	/*
181 	 * Checking for _PAGE_LEAF is needed too because:
182 	 * When splitting a THP, split_huge_page() will temporarily clear
183 	 * the present bit, in this situation, pmd_present() and
184 	 * pmd_trans_huge() still needs to return true.
185 	 */
186 	return (pmd_val(pmd) & (_PAGE_PRESENT | _PAGE_PROT_NONE | _PAGE_LEAF));
187 }
188 #else
189 static inline int pmd_present(pmd_t pmd)
190 {
191 	return (pmd_val(pmd) & (_PAGE_PRESENT | _PAGE_PROT_NONE));
192 }
193 #endif
194 
195 static inline int pmd_none(pmd_t pmd)
196 {
197 	return (pmd_val(pmd) == 0);
198 }
199 
200 static inline int pmd_bad(pmd_t pmd)
201 {
202 	return !pmd_present(pmd) || (pmd_val(pmd) & _PAGE_LEAF);
203 }
204 
205 #define pmd_leaf	pmd_leaf
206 static inline int pmd_leaf(pmd_t pmd)
207 {
208 	return pmd_present(pmd) && (pmd_val(pmd) & _PAGE_LEAF);
209 }
210 
211 static inline void set_pmd(pmd_t *pmdp, pmd_t pmd)
212 {
213 	*pmdp = pmd;
214 }
215 
216 static inline void pmd_clear(pmd_t *pmdp)
217 {
218 	set_pmd(pmdp, __pmd(0));
219 }
220 
221 static inline pgd_t pfn_pgd(unsigned long pfn, pgprot_t prot)
222 {
223 	return __pgd((pfn << _PAGE_PFN_SHIFT) | pgprot_val(prot));
224 }
225 
226 static inline unsigned long _pgd_pfn(pgd_t pgd)
227 {
228 	return pgd_val(pgd) >> _PAGE_PFN_SHIFT;
229 }
230 
231 static inline struct page *pmd_page(pmd_t pmd)
232 {
233 	return pfn_to_page(pmd_val(pmd) >> _PAGE_PFN_SHIFT);
234 }
235 
236 static inline unsigned long pmd_page_vaddr(pmd_t pmd)
237 {
238 	return (unsigned long)pfn_to_virt(pmd_val(pmd) >> _PAGE_PFN_SHIFT);
239 }
240 
241 static inline pte_t pmd_pte(pmd_t pmd)
242 {
243 	return __pte(pmd_val(pmd));
244 }
245 
246 static inline pte_t pud_pte(pud_t pud)
247 {
248 	return __pte(pud_val(pud));
249 }
250 
251 /* Yields the page frame number (PFN) of a page table entry */
252 static inline unsigned long pte_pfn(pte_t pte)
253 {
254 	return (pte_val(pte) >> _PAGE_PFN_SHIFT);
255 }
256 
257 #define pte_page(x)     pfn_to_page(pte_pfn(x))
258 
259 /* Constructs a page table entry */
260 static inline pte_t pfn_pte(unsigned long pfn, pgprot_t prot)
261 {
262 	return __pte((pfn << _PAGE_PFN_SHIFT) | pgprot_val(prot));
263 }
264 
265 #define mk_pte(page, prot)       pfn_pte(page_to_pfn(page), prot)
266 
267 static inline int pte_present(pte_t pte)
268 {
269 	return (pte_val(pte) & (_PAGE_PRESENT | _PAGE_PROT_NONE));
270 }
271 
272 static inline int pte_none(pte_t pte)
273 {
274 	return (pte_val(pte) == 0);
275 }
276 
277 static inline int pte_write(pte_t pte)
278 {
279 	return pte_val(pte) & _PAGE_WRITE;
280 }
281 
282 static inline int pte_exec(pte_t pte)
283 {
284 	return pte_val(pte) & _PAGE_EXEC;
285 }
286 
287 static inline int pte_huge(pte_t pte)
288 {
289 	return pte_present(pte) && (pte_val(pte) & _PAGE_LEAF);
290 }
291 
292 static inline int pte_dirty(pte_t pte)
293 {
294 	return pte_val(pte) & _PAGE_DIRTY;
295 }
296 
297 static inline int pte_young(pte_t pte)
298 {
299 	return pte_val(pte) & _PAGE_ACCESSED;
300 }
301 
302 static inline int pte_special(pte_t pte)
303 {
304 	return pte_val(pte) & _PAGE_SPECIAL;
305 }
306 
307 /* static inline pte_t pte_rdprotect(pte_t pte) */
308 
309 static inline pte_t pte_wrprotect(pte_t pte)
310 {
311 	return __pte(pte_val(pte) & ~(_PAGE_WRITE));
312 }
313 
314 /* static inline pte_t pte_mkread(pte_t pte) */
315 
316 static inline pte_t pte_mkwrite(pte_t pte)
317 {
318 	return __pte(pte_val(pte) | _PAGE_WRITE);
319 }
320 
321 /* static inline pte_t pte_mkexec(pte_t pte) */
322 
323 static inline pte_t pte_mkdirty(pte_t pte)
324 {
325 	return __pte(pte_val(pte) | _PAGE_DIRTY);
326 }
327 
328 static inline pte_t pte_mkclean(pte_t pte)
329 {
330 	return __pte(pte_val(pte) & ~(_PAGE_DIRTY));
331 }
332 
333 static inline pte_t pte_mkyoung(pte_t pte)
334 {
335 	return __pte(pte_val(pte) | _PAGE_ACCESSED);
336 }
337 
338 static inline pte_t pte_mkold(pte_t pte)
339 {
340 	return __pte(pte_val(pte) & ~(_PAGE_ACCESSED));
341 }
342 
343 static inline pte_t pte_mkspecial(pte_t pte)
344 {
345 	return __pte(pte_val(pte) | _PAGE_SPECIAL);
346 }
347 
348 static inline pte_t pte_mkhuge(pte_t pte)
349 {
350 	return pte;
351 }
352 
353 #ifdef CONFIG_NUMA_BALANCING
354 /*
355  * See the comment in include/asm-generic/pgtable.h
356  */
357 static inline int pte_protnone(pte_t pte)
358 {
359 	return (pte_val(pte) & (_PAGE_PRESENT | _PAGE_PROT_NONE)) == _PAGE_PROT_NONE;
360 }
361 
362 static inline int pmd_protnone(pmd_t pmd)
363 {
364 	return pte_protnone(pmd_pte(pmd));
365 }
366 #endif
367 
368 /* Modify page protection bits */
369 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
370 {
371 	return __pte((pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot));
372 }
373 
374 #define pgd_ERROR(e) \
375 	pr_err("%s:%d: bad pgd " PTE_FMT ".\n", __FILE__, __LINE__, pgd_val(e))
376 
377 
378 /* Commit new configuration to MMU hardware */
379 static inline void update_mmu_cache(struct vm_area_struct *vma,
380 	unsigned long address, pte_t *ptep)
381 {
382 	/*
383 	 * The kernel assumes that TLBs don't cache invalid entries, but
384 	 * in RISC-V, SFENCE.VMA specifies an ordering constraint, not a
385 	 * cache flush; it is necessary even after writing invalid entries.
386 	 * Relying on flush_tlb_fix_spurious_fault would suffice, but
387 	 * the extra traps reduce performance.  So, eagerly SFENCE.VMA.
388 	 */
389 	local_flush_tlb_page(address);
390 }
391 
392 static inline void update_mmu_cache_pmd(struct vm_area_struct *vma,
393 		unsigned long address, pmd_t *pmdp)
394 {
395 	pte_t *ptep = (pte_t *)pmdp;
396 
397 	update_mmu_cache(vma, address, ptep);
398 }
399 
400 #define __HAVE_ARCH_PTE_SAME
401 static inline int pte_same(pte_t pte_a, pte_t pte_b)
402 {
403 	return pte_val(pte_a) == pte_val(pte_b);
404 }
405 
406 /*
407  * Certain architectures need to do special things when PTEs within
408  * a page table are directly modified.  Thus, the following hook is
409  * made available.
410  */
411 static inline void set_pte(pte_t *ptep, pte_t pteval)
412 {
413 	*ptep = pteval;
414 }
415 
416 void flush_icache_pte(pte_t pte);
417 
418 static inline void set_pte_at(struct mm_struct *mm,
419 	unsigned long addr, pte_t *ptep, pte_t pteval)
420 {
421 	if (pte_present(pteval) && pte_exec(pteval))
422 		flush_icache_pte(pteval);
423 
424 	set_pte(ptep, pteval);
425 }
426 
427 static inline void pte_clear(struct mm_struct *mm,
428 	unsigned long addr, pte_t *ptep)
429 {
430 	set_pte_at(mm, addr, ptep, __pte(0));
431 }
432 
433 #define __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
434 static inline int ptep_set_access_flags(struct vm_area_struct *vma,
435 					unsigned long address, pte_t *ptep,
436 					pte_t entry, int dirty)
437 {
438 	if (!pte_same(*ptep, entry))
439 		set_pte_at(vma->vm_mm, address, ptep, entry);
440 	/*
441 	 * update_mmu_cache will unconditionally execute, handling both
442 	 * the case that the PTE changed and the spurious fault case.
443 	 */
444 	return true;
445 }
446 
447 #define __HAVE_ARCH_PTEP_GET_AND_CLEAR
448 static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
449 				       unsigned long address, pte_t *ptep)
450 {
451 	return __pte(atomic_long_xchg((atomic_long_t *)ptep, 0));
452 }
453 
454 #define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
455 static inline int ptep_test_and_clear_young(struct vm_area_struct *vma,
456 					    unsigned long address,
457 					    pte_t *ptep)
458 {
459 	if (!pte_young(*ptep))
460 		return 0;
461 	return test_and_clear_bit(_PAGE_ACCESSED_OFFSET, &pte_val(*ptep));
462 }
463 
464 #define __HAVE_ARCH_PTEP_SET_WRPROTECT
465 static inline void ptep_set_wrprotect(struct mm_struct *mm,
466 				      unsigned long address, pte_t *ptep)
467 {
468 	atomic_long_and(~(unsigned long)_PAGE_WRITE, (atomic_long_t *)ptep);
469 }
470 
471 #define __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
472 static inline int ptep_clear_flush_young(struct vm_area_struct *vma,
473 					 unsigned long address, pte_t *ptep)
474 {
475 	/*
476 	 * This comment is borrowed from x86, but applies equally to RISC-V:
477 	 *
478 	 * Clearing the accessed bit without a TLB flush
479 	 * doesn't cause data corruption. [ It could cause incorrect
480 	 * page aging and the (mistaken) reclaim of hot pages, but the
481 	 * chance of that should be relatively low. ]
482 	 *
483 	 * So as a performance optimization don't flush the TLB when
484 	 * clearing the accessed bit, it will eventually be flushed by
485 	 * a context switch or a VM operation anyway. [ In the rare
486 	 * event of it not getting flushed for a long time the delay
487 	 * shouldn't really matter because there's no real memory
488 	 * pressure for swapout to react to. ]
489 	 */
490 	return ptep_test_and_clear_young(vma, address, ptep);
491 }
492 
493 /*
494  * THP functions
495  */
496 static inline pmd_t pte_pmd(pte_t pte)
497 {
498 	return __pmd(pte_val(pte));
499 }
500 
501 static inline pmd_t pmd_mkhuge(pmd_t pmd)
502 {
503 	return pmd;
504 }
505 
506 static inline pmd_t pmd_mkinvalid(pmd_t pmd)
507 {
508 	return __pmd(pmd_val(pmd) & ~(_PAGE_PRESENT|_PAGE_PROT_NONE));
509 }
510 
511 #define __pmd_to_phys(pmd)  (pmd_val(pmd) >> _PAGE_PFN_SHIFT << PAGE_SHIFT)
512 
513 static inline unsigned long pmd_pfn(pmd_t pmd)
514 {
515 	return ((__pmd_to_phys(pmd) & PMD_MASK) >> PAGE_SHIFT);
516 }
517 
518 static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot)
519 {
520 	return pte_pmd(pte_modify(pmd_pte(pmd), newprot));
521 }
522 
523 #define pmd_write pmd_write
524 static inline int pmd_write(pmd_t pmd)
525 {
526 	return pte_write(pmd_pte(pmd));
527 }
528 
529 static inline int pmd_dirty(pmd_t pmd)
530 {
531 	return pte_dirty(pmd_pte(pmd));
532 }
533 
534 static inline int pmd_young(pmd_t pmd)
535 {
536 	return pte_young(pmd_pte(pmd));
537 }
538 
539 static inline pmd_t pmd_mkold(pmd_t pmd)
540 {
541 	return pte_pmd(pte_mkold(pmd_pte(pmd)));
542 }
543 
544 static inline pmd_t pmd_mkyoung(pmd_t pmd)
545 {
546 	return pte_pmd(pte_mkyoung(pmd_pte(pmd)));
547 }
548 
549 static inline pmd_t pmd_mkwrite(pmd_t pmd)
550 {
551 	return pte_pmd(pte_mkwrite(pmd_pte(pmd)));
552 }
553 
554 static inline pmd_t pmd_wrprotect(pmd_t pmd)
555 {
556 	return pte_pmd(pte_wrprotect(pmd_pte(pmd)));
557 }
558 
559 static inline pmd_t pmd_mkclean(pmd_t pmd)
560 {
561 	return pte_pmd(pte_mkclean(pmd_pte(pmd)));
562 }
563 
564 static inline pmd_t pmd_mkdirty(pmd_t pmd)
565 {
566 	return pte_pmd(pte_mkdirty(pmd_pte(pmd)));
567 }
568 
569 static inline void set_pmd_at(struct mm_struct *mm, unsigned long addr,
570 				pmd_t *pmdp, pmd_t pmd)
571 {
572 	return set_pte_at(mm, addr, (pte_t *)pmdp, pmd_pte(pmd));
573 }
574 
575 static inline void set_pud_at(struct mm_struct *mm, unsigned long addr,
576 				pud_t *pudp, pud_t pud)
577 {
578 	return set_pte_at(mm, addr, (pte_t *)pudp, pud_pte(pud));
579 }
580 
581 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
582 static inline int pmd_trans_huge(pmd_t pmd)
583 {
584 	return pmd_leaf(pmd);
585 }
586 
587 #define __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS
588 static inline int pmdp_set_access_flags(struct vm_area_struct *vma,
589 					unsigned long address, pmd_t *pmdp,
590 					pmd_t entry, int dirty)
591 {
592 	return ptep_set_access_flags(vma, address, (pte_t *)pmdp, pmd_pte(entry), dirty);
593 }
594 
595 #define __HAVE_ARCH_PMDP_TEST_AND_CLEAR_YOUNG
596 static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma,
597 					unsigned long address, pmd_t *pmdp)
598 {
599 	return ptep_test_and_clear_young(vma, address, (pte_t *)pmdp);
600 }
601 
602 #define __HAVE_ARCH_PMDP_HUGE_GET_AND_CLEAR
603 static inline pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm,
604 					unsigned long address, pmd_t *pmdp)
605 {
606 	return pte_pmd(ptep_get_and_clear(mm, address, (pte_t *)pmdp));
607 }
608 
609 #define __HAVE_ARCH_PMDP_SET_WRPROTECT
610 static inline void pmdp_set_wrprotect(struct mm_struct *mm,
611 					unsigned long address, pmd_t *pmdp)
612 {
613 	ptep_set_wrprotect(mm, address, (pte_t *)pmdp);
614 }
615 
616 #define pmdp_establish pmdp_establish
617 static inline pmd_t pmdp_establish(struct vm_area_struct *vma,
618 				unsigned long address, pmd_t *pmdp, pmd_t pmd)
619 {
620 	return __pmd(atomic_long_xchg((atomic_long_t *)pmdp, pmd_val(pmd)));
621 }
622 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
623 
624 /*
625  * Encode and decode a swap entry
626  *
627  * Format of swap PTE:
628  *	bit            0:	_PAGE_PRESENT (zero)
629  *	bit            1:	_PAGE_PROT_NONE (zero)
630  *	bits      2 to 6:	swap type
631  *	bits 7 to XLEN-1:	swap offset
632  */
633 #define __SWP_TYPE_SHIFT	2
634 #define __SWP_TYPE_BITS		5
635 #define __SWP_TYPE_MASK		((1UL << __SWP_TYPE_BITS) - 1)
636 #define __SWP_OFFSET_SHIFT	(__SWP_TYPE_BITS + __SWP_TYPE_SHIFT)
637 
638 #define MAX_SWAPFILES_CHECK()	\
639 	BUILD_BUG_ON(MAX_SWAPFILES_SHIFT > __SWP_TYPE_BITS)
640 
641 #define __swp_type(x)	(((x).val >> __SWP_TYPE_SHIFT) & __SWP_TYPE_MASK)
642 #define __swp_offset(x)	((x).val >> __SWP_OFFSET_SHIFT)
643 #define __swp_entry(type, offset) ((swp_entry_t) \
644 	{ ((type) << __SWP_TYPE_SHIFT) | ((offset) << __SWP_OFFSET_SHIFT) })
645 
646 #define __pte_to_swp_entry(pte)	((swp_entry_t) { pte_val(pte) })
647 #define __swp_entry_to_pte(x)	((pte_t) { (x).val })
648 
649 /*
650  * In the RV64 Linux scheme, we give the user half of the virtual-address space
651  * and give the kernel the other (upper) half.
652  */
653 #ifdef CONFIG_64BIT
654 #define KERN_VIRT_START	(-(BIT(CONFIG_VA_BITS)) + TASK_SIZE)
655 #else
656 #define KERN_VIRT_START	FIXADDR_START
657 #endif
658 
659 /*
660  * Task size is 0x4000000000 for RV64 or 0x9fc00000 for RV32.
661  * Note that PGDIR_SIZE must evenly divide TASK_SIZE.
662  */
663 #ifdef CONFIG_64BIT
664 #define TASK_SIZE (PGDIR_SIZE * PTRS_PER_PGD / 2)
665 #else
666 #define TASK_SIZE FIXADDR_START
667 #endif
668 
669 #else /* CONFIG_MMU */
670 
671 #define PAGE_SHARED		__pgprot(0)
672 #define PAGE_KERNEL		__pgprot(0)
673 #define swapper_pg_dir		NULL
674 #define TASK_SIZE		0xffffffffUL
675 #define VMALLOC_START		0
676 #define VMALLOC_END		TASK_SIZE
677 
678 #endif /* !CONFIG_MMU */
679 
680 #define kern_addr_valid(addr)   (1) /* FIXME */
681 
682 extern char _start[];
683 extern void *_dtb_early_va;
684 extern uintptr_t _dtb_early_pa;
685 #if defined(CONFIG_XIP_KERNEL) && defined(CONFIG_MMU)
686 #define dtb_early_va	(*(void **)XIP_FIXUP(&_dtb_early_va))
687 #define dtb_early_pa	(*(uintptr_t *)XIP_FIXUP(&_dtb_early_pa))
688 #else
689 #define dtb_early_va	_dtb_early_va
690 #define dtb_early_pa	_dtb_early_pa
691 #endif /* CONFIG_XIP_KERNEL */
692 
693 void paging_init(void);
694 void misc_mem_init(void);
695 
696 /*
697  * ZERO_PAGE is a global shared page that is always zero,
698  * used for zero-mapped memory areas, etc.
699  */
700 extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)];
701 #define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
702 
703 #endif /* !__ASSEMBLY__ */
704 
705 #endif /* _ASM_RISCV_PGTABLE_H */
706