xref: /openbmc/linux/arch/riscv/include/asm/pgtable.h (revision 405db98b)
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_32M
79 #define XIP_OFFSET_MASK		(SZ_32M - 1)
80 #else
81 #define XIP_OFFSET		0
82 #endif
83 
84 #ifndef __ASSEMBLY__
85 
86 /* Page Upper Directory not used in RISC-V */
87 #include <asm-generic/pgtable-nopud.h>
88 #include <asm/page.h>
89 #include <asm/tlbflush.h>
90 #include <linux/mm_types.h>
91 
92 #ifdef CONFIG_64BIT
93 #include <asm/pgtable-64.h>
94 #else
95 #include <asm/pgtable-32.h>
96 #endif /* CONFIG_64BIT */
97 
98 #ifdef CONFIG_XIP_KERNEL
99 #define XIP_FIXUP(addr) ({							\
100 	uintptr_t __a = (uintptr_t)(addr);					\
101 	(__a >= CONFIG_XIP_PHYS_ADDR && \
102 	 __a < CONFIG_XIP_PHYS_ADDR + XIP_OFFSET * 2) ?	\
103 		__a - CONFIG_XIP_PHYS_ADDR + CONFIG_PHYS_RAM_BASE - XIP_OFFSET :\
104 		__a;								\
105 	})
106 #else
107 #define XIP_FIXUP(addr)		(addr)
108 #endif /* CONFIG_XIP_KERNEL */
109 
110 #ifdef CONFIG_MMU
111 /* Number of entries in the page global directory */
112 #define PTRS_PER_PGD    (PAGE_SIZE / sizeof(pgd_t))
113 /* Number of entries in the page table */
114 #define PTRS_PER_PTE    (PAGE_SIZE / sizeof(pte_t))
115 
116 /* Number of PGD entries that a user-mode program can use */
117 #define USER_PTRS_PER_PGD   (TASK_SIZE / PGDIR_SIZE)
118 
119 /* Page protection bits */
120 #define _PAGE_BASE	(_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_USER)
121 
122 #define PAGE_NONE		__pgprot(_PAGE_PROT_NONE)
123 #define PAGE_READ		__pgprot(_PAGE_BASE | _PAGE_READ)
124 #define PAGE_WRITE		__pgprot(_PAGE_BASE | _PAGE_READ | _PAGE_WRITE)
125 #define PAGE_EXEC		__pgprot(_PAGE_BASE | _PAGE_EXEC)
126 #define PAGE_READ_EXEC		__pgprot(_PAGE_BASE | _PAGE_READ | _PAGE_EXEC)
127 #define PAGE_WRITE_EXEC		__pgprot(_PAGE_BASE | _PAGE_READ |	\
128 					 _PAGE_EXEC | _PAGE_WRITE)
129 
130 #define PAGE_COPY		PAGE_READ
131 #define PAGE_COPY_EXEC		PAGE_EXEC
132 #define PAGE_COPY_READ_EXEC	PAGE_READ_EXEC
133 #define PAGE_SHARED		PAGE_WRITE
134 #define PAGE_SHARED_EXEC	PAGE_WRITE_EXEC
135 
136 #define _PAGE_KERNEL		(_PAGE_READ \
137 				| _PAGE_WRITE \
138 				| _PAGE_PRESENT \
139 				| _PAGE_ACCESSED \
140 				| _PAGE_DIRTY \
141 				| _PAGE_GLOBAL)
142 
143 #define PAGE_KERNEL		__pgprot(_PAGE_KERNEL)
144 #define PAGE_KERNEL_READ	__pgprot(_PAGE_KERNEL & ~_PAGE_WRITE)
145 #define PAGE_KERNEL_EXEC	__pgprot(_PAGE_KERNEL | _PAGE_EXEC)
146 #define PAGE_KERNEL_READ_EXEC	__pgprot((_PAGE_KERNEL & ~_PAGE_WRITE) \
147 					 | _PAGE_EXEC)
148 
149 #define PAGE_TABLE		__pgprot(_PAGE_TABLE)
150 
151 /*
152  * The RISC-V ISA doesn't yet specify how to query or modify PMAs, so we can't
153  * change the properties of memory regions.
154  */
155 #define _PAGE_IOREMAP _PAGE_KERNEL
156 
157 extern pgd_t swapper_pg_dir[];
158 
159 /* MAP_PRIVATE permissions: xwr (copy-on-write) */
160 #define __P000	PAGE_NONE
161 #define __P001	PAGE_READ
162 #define __P010	PAGE_COPY
163 #define __P011	PAGE_COPY
164 #define __P100	PAGE_EXEC
165 #define __P101	PAGE_READ_EXEC
166 #define __P110	PAGE_COPY_EXEC
167 #define __P111	PAGE_COPY_READ_EXEC
168 
169 /* MAP_SHARED permissions: xwr */
170 #define __S000	PAGE_NONE
171 #define __S001	PAGE_READ
172 #define __S010	PAGE_SHARED
173 #define __S011	PAGE_SHARED
174 #define __S100	PAGE_EXEC
175 #define __S101	PAGE_READ_EXEC
176 #define __S110	PAGE_SHARED_EXEC
177 #define __S111	PAGE_SHARED_EXEC
178 
179 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
180 static inline int pmd_present(pmd_t pmd)
181 {
182 	/*
183 	 * Checking for _PAGE_LEAF is needed too because:
184 	 * When splitting a THP, split_huge_page() will temporarily clear
185 	 * the present bit, in this situation, pmd_present() and
186 	 * pmd_trans_huge() still needs to return true.
187 	 */
188 	return (pmd_val(pmd) & (_PAGE_PRESENT | _PAGE_PROT_NONE | _PAGE_LEAF));
189 }
190 #else
191 static inline int pmd_present(pmd_t pmd)
192 {
193 	return (pmd_val(pmd) & (_PAGE_PRESENT | _PAGE_PROT_NONE));
194 }
195 #endif
196 
197 static inline int pmd_none(pmd_t pmd)
198 {
199 	return (pmd_val(pmd) == 0);
200 }
201 
202 static inline int pmd_bad(pmd_t pmd)
203 {
204 	return !pmd_present(pmd) || (pmd_val(pmd) & _PAGE_LEAF);
205 }
206 
207 #define pmd_leaf	pmd_leaf
208 static inline int pmd_leaf(pmd_t pmd)
209 {
210 	return pmd_present(pmd) && (pmd_val(pmd) & _PAGE_LEAF);
211 }
212 
213 static inline void set_pmd(pmd_t *pmdp, pmd_t pmd)
214 {
215 	*pmdp = pmd;
216 }
217 
218 static inline void pmd_clear(pmd_t *pmdp)
219 {
220 	set_pmd(pmdp, __pmd(0));
221 }
222 
223 static inline pgd_t pfn_pgd(unsigned long pfn, pgprot_t prot)
224 {
225 	return __pgd((pfn << _PAGE_PFN_SHIFT) | pgprot_val(prot));
226 }
227 
228 static inline unsigned long _pgd_pfn(pgd_t pgd)
229 {
230 	return pgd_val(pgd) >> _PAGE_PFN_SHIFT;
231 }
232 
233 static inline struct page *pmd_page(pmd_t pmd)
234 {
235 	return pfn_to_page(pmd_val(pmd) >> _PAGE_PFN_SHIFT);
236 }
237 
238 static inline unsigned long pmd_page_vaddr(pmd_t pmd)
239 {
240 	return (unsigned long)pfn_to_virt(pmd_val(pmd) >> _PAGE_PFN_SHIFT);
241 }
242 
243 static inline pte_t pmd_pte(pmd_t pmd)
244 {
245 	return __pte(pmd_val(pmd));
246 }
247 
248 static inline pte_t pud_pte(pud_t pud)
249 {
250 	return __pte(pud_val(pud));
251 }
252 
253 /* Yields the page frame number (PFN) of a page table entry */
254 static inline unsigned long pte_pfn(pte_t pte)
255 {
256 	return (pte_val(pte) >> _PAGE_PFN_SHIFT);
257 }
258 
259 #define pte_page(x)     pfn_to_page(pte_pfn(x))
260 
261 /* Constructs a page table entry */
262 static inline pte_t pfn_pte(unsigned long pfn, pgprot_t prot)
263 {
264 	return __pte((pfn << _PAGE_PFN_SHIFT) | pgprot_val(prot));
265 }
266 
267 #define mk_pte(page, prot)       pfn_pte(page_to_pfn(page), prot)
268 
269 static inline int pte_present(pte_t pte)
270 {
271 	return (pte_val(pte) & (_PAGE_PRESENT | _PAGE_PROT_NONE));
272 }
273 
274 static inline int pte_none(pte_t pte)
275 {
276 	return (pte_val(pte) == 0);
277 }
278 
279 static inline int pte_write(pte_t pte)
280 {
281 	return pte_val(pte) & _PAGE_WRITE;
282 }
283 
284 static inline int pte_exec(pte_t pte)
285 {
286 	return pte_val(pte) & _PAGE_EXEC;
287 }
288 
289 static inline int pte_huge(pte_t pte)
290 {
291 	return pte_present(pte) && (pte_val(pte) & _PAGE_LEAF);
292 }
293 
294 static inline int pte_dirty(pte_t pte)
295 {
296 	return pte_val(pte) & _PAGE_DIRTY;
297 }
298 
299 static inline int pte_young(pte_t pte)
300 {
301 	return pte_val(pte) & _PAGE_ACCESSED;
302 }
303 
304 static inline int pte_special(pte_t pte)
305 {
306 	return pte_val(pte) & _PAGE_SPECIAL;
307 }
308 
309 /* static inline pte_t pte_rdprotect(pte_t pte) */
310 
311 static inline pte_t pte_wrprotect(pte_t pte)
312 {
313 	return __pte(pte_val(pte) & ~(_PAGE_WRITE));
314 }
315 
316 /* static inline pte_t pte_mkread(pte_t pte) */
317 
318 static inline pte_t pte_mkwrite(pte_t pte)
319 {
320 	return __pte(pte_val(pte) | _PAGE_WRITE);
321 }
322 
323 /* static inline pte_t pte_mkexec(pte_t pte) */
324 
325 static inline pte_t pte_mkdirty(pte_t pte)
326 {
327 	return __pte(pte_val(pte) | _PAGE_DIRTY);
328 }
329 
330 static inline pte_t pte_mkclean(pte_t pte)
331 {
332 	return __pte(pte_val(pte) & ~(_PAGE_DIRTY));
333 }
334 
335 static inline pte_t pte_mkyoung(pte_t pte)
336 {
337 	return __pte(pte_val(pte) | _PAGE_ACCESSED);
338 }
339 
340 static inline pte_t pte_mkold(pte_t pte)
341 {
342 	return __pte(pte_val(pte) & ~(_PAGE_ACCESSED));
343 }
344 
345 static inline pte_t pte_mkspecial(pte_t pte)
346 {
347 	return __pte(pte_val(pte) | _PAGE_SPECIAL);
348 }
349 
350 static inline pte_t pte_mkhuge(pte_t pte)
351 {
352 	return pte;
353 }
354 
355 #ifdef CONFIG_NUMA_BALANCING
356 /*
357  * See the comment in include/asm-generic/pgtable.h
358  */
359 static inline int pte_protnone(pte_t pte)
360 {
361 	return (pte_val(pte) & (_PAGE_PRESENT | _PAGE_PROT_NONE)) == _PAGE_PROT_NONE;
362 }
363 
364 static inline int pmd_protnone(pmd_t pmd)
365 {
366 	return pte_protnone(pmd_pte(pmd));
367 }
368 #endif
369 
370 /* Modify page protection bits */
371 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
372 {
373 	return __pte((pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot));
374 }
375 
376 #define pgd_ERROR(e) \
377 	pr_err("%s:%d: bad pgd " PTE_FMT ".\n", __FILE__, __LINE__, pgd_val(e))
378 
379 
380 /* Commit new configuration to MMU hardware */
381 static inline void update_mmu_cache(struct vm_area_struct *vma,
382 	unsigned long address, pte_t *ptep)
383 {
384 	/*
385 	 * The kernel assumes that TLBs don't cache invalid entries, but
386 	 * in RISC-V, SFENCE.VMA specifies an ordering constraint, not a
387 	 * cache flush; it is necessary even after writing invalid entries.
388 	 * Relying on flush_tlb_fix_spurious_fault would suffice, but
389 	 * the extra traps reduce performance.  So, eagerly SFENCE.VMA.
390 	 */
391 	local_flush_tlb_page(address);
392 }
393 
394 static inline void update_mmu_cache_pmd(struct vm_area_struct *vma,
395 		unsigned long address, pmd_t *pmdp)
396 {
397 	pte_t *ptep = (pte_t *)pmdp;
398 
399 	update_mmu_cache(vma, address, ptep);
400 }
401 
402 #define __HAVE_ARCH_PTE_SAME
403 static inline int pte_same(pte_t pte_a, pte_t pte_b)
404 {
405 	return pte_val(pte_a) == pte_val(pte_b);
406 }
407 
408 /*
409  * Certain architectures need to do special things when PTEs within
410  * a page table are directly modified.  Thus, the following hook is
411  * made available.
412  */
413 static inline void set_pte(pte_t *ptep, pte_t pteval)
414 {
415 	*ptep = pteval;
416 }
417 
418 void flush_icache_pte(pte_t pte);
419 
420 static inline void set_pte_at(struct mm_struct *mm,
421 	unsigned long addr, pte_t *ptep, pte_t pteval)
422 {
423 	if (pte_present(pteval) && pte_exec(pteval))
424 		flush_icache_pte(pteval);
425 
426 	set_pte(ptep, pteval);
427 }
428 
429 static inline void pte_clear(struct mm_struct *mm,
430 	unsigned long addr, pte_t *ptep)
431 {
432 	set_pte_at(mm, addr, ptep, __pte(0));
433 }
434 
435 #define __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
436 static inline int ptep_set_access_flags(struct vm_area_struct *vma,
437 					unsigned long address, pte_t *ptep,
438 					pte_t entry, int dirty)
439 {
440 	if (!pte_same(*ptep, entry))
441 		set_pte_at(vma->vm_mm, address, ptep, entry);
442 	/*
443 	 * update_mmu_cache will unconditionally execute, handling both
444 	 * the case that the PTE changed and the spurious fault case.
445 	 */
446 	return true;
447 }
448 
449 #define __HAVE_ARCH_PTEP_GET_AND_CLEAR
450 static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
451 				       unsigned long address, pte_t *ptep)
452 {
453 	return __pte(atomic_long_xchg((atomic_long_t *)ptep, 0));
454 }
455 
456 #define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
457 static inline int ptep_test_and_clear_young(struct vm_area_struct *vma,
458 					    unsigned long address,
459 					    pte_t *ptep)
460 {
461 	if (!pte_young(*ptep))
462 		return 0;
463 	return test_and_clear_bit(_PAGE_ACCESSED_OFFSET, &pte_val(*ptep));
464 }
465 
466 #define __HAVE_ARCH_PTEP_SET_WRPROTECT
467 static inline void ptep_set_wrprotect(struct mm_struct *mm,
468 				      unsigned long address, pte_t *ptep)
469 {
470 	atomic_long_and(~(unsigned long)_PAGE_WRITE, (atomic_long_t *)ptep);
471 }
472 
473 #define __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
474 static inline int ptep_clear_flush_young(struct vm_area_struct *vma,
475 					 unsigned long address, pte_t *ptep)
476 {
477 	/*
478 	 * This comment is borrowed from x86, but applies equally to RISC-V:
479 	 *
480 	 * Clearing the accessed bit without a TLB flush
481 	 * doesn't cause data corruption. [ It could cause incorrect
482 	 * page aging and the (mistaken) reclaim of hot pages, but the
483 	 * chance of that should be relatively low. ]
484 	 *
485 	 * So as a performance optimization don't flush the TLB when
486 	 * clearing the accessed bit, it will eventually be flushed by
487 	 * a context switch or a VM operation anyway. [ In the rare
488 	 * event of it not getting flushed for a long time the delay
489 	 * shouldn't really matter because there's no real memory
490 	 * pressure for swapout to react to. ]
491 	 */
492 	return ptep_test_and_clear_young(vma, address, ptep);
493 }
494 
495 /*
496  * THP functions
497  */
498 static inline pmd_t pte_pmd(pte_t pte)
499 {
500 	return __pmd(pte_val(pte));
501 }
502 
503 static inline pmd_t pmd_mkhuge(pmd_t pmd)
504 {
505 	return pmd;
506 }
507 
508 static inline pmd_t pmd_mkinvalid(pmd_t pmd)
509 {
510 	return __pmd(pmd_val(pmd) & ~(_PAGE_PRESENT|_PAGE_PROT_NONE));
511 }
512 
513 #define __pmd_to_phys(pmd)  (pmd_val(pmd) >> _PAGE_PFN_SHIFT << PAGE_SHIFT)
514 
515 static inline unsigned long pmd_pfn(pmd_t pmd)
516 {
517 	return ((__pmd_to_phys(pmd) & PMD_MASK) >> PAGE_SHIFT);
518 }
519 
520 static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot)
521 {
522 	return pte_pmd(pte_modify(pmd_pte(pmd), newprot));
523 }
524 
525 #define pmd_write pmd_write
526 static inline int pmd_write(pmd_t pmd)
527 {
528 	return pte_write(pmd_pte(pmd));
529 }
530 
531 static inline int pmd_dirty(pmd_t pmd)
532 {
533 	return pte_dirty(pmd_pte(pmd));
534 }
535 
536 static inline int pmd_young(pmd_t pmd)
537 {
538 	return pte_young(pmd_pte(pmd));
539 }
540 
541 static inline pmd_t pmd_mkold(pmd_t pmd)
542 {
543 	return pte_pmd(pte_mkold(pmd_pte(pmd)));
544 }
545 
546 static inline pmd_t pmd_mkyoung(pmd_t pmd)
547 {
548 	return pte_pmd(pte_mkyoung(pmd_pte(pmd)));
549 }
550 
551 static inline pmd_t pmd_mkwrite(pmd_t pmd)
552 {
553 	return pte_pmd(pte_mkwrite(pmd_pte(pmd)));
554 }
555 
556 static inline pmd_t pmd_wrprotect(pmd_t pmd)
557 {
558 	return pte_pmd(pte_wrprotect(pmd_pte(pmd)));
559 }
560 
561 static inline pmd_t pmd_mkclean(pmd_t pmd)
562 {
563 	return pte_pmd(pte_mkclean(pmd_pte(pmd)));
564 }
565 
566 static inline pmd_t pmd_mkdirty(pmd_t pmd)
567 {
568 	return pte_pmd(pte_mkdirty(pmd_pte(pmd)));
569 }
570 
571 static inline void set_pmd_at(struct mm_struct *mm, unsigned long addr,
572 				pmd_t *pmdp, pmd_t pmd)
573 {
574 	return set_pte_at(mm, addr, (pte_t *)pmdp, pmd_pte(pmd));
575 }
576 
577 static inline void set_pud_at(struct mm_struct *mm, unsigned long addr,
578 				pud_t *pudp, pud_t pud)
579 {
580 	return set_pte_at(mm, addr, (pte_t *)pudp, pud_pte(pud));
581 }
582 
583 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
584 static inline int pmd_trans_huge(pmd_t pmd)
585 {
586 	return pmd_leaf(pmd);
587 }
588 
589 #define __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS
590 static inline int pmdp_set_access_flags(struct vm_area_struct *vma,
591 					unsigned long address, pmd_t *pmdp,
592 					pmd_t entry, int dirty)
593 {
594 	return ptep_set_access_flags(vma, address, (pte_t *)pmdp, pmd_pte(entry), dirty);
595 }
596 
597 #define __HAVE_ARCH_PMDP_TEST_AND_CLEAR_YOUNG
598 static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma,
599 					unsigned long address, pmd_t *pmdp)
600 {
601 	return ptep_test_and_clear_young(vma, address, (pte_t *)pmdp);
602 }
603 
604 #define __HAVE_ARCH_PMDP_HUGE_GET_AND_CLEAR
605 static inline pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm,
606 					unsigned long address, pmd_t *pmdp)
607 {
608 	return pte_pmd(ptep_get_and_clear(mm, address, (pte_t *)pmdp));
609 }
610 
611 #define __HAVE_ARCH_PMDP_SET_WRPROTECT
612 static inline void pmdp_set_wrprotect(struct mm_struct *mm,
613 					unsigned long address, pmd_t *pmdp)
614 {
615 	ptep_set_wrprotect(mm, address, (pte_t *)pmdp);
616 }
617 
618 #define pmdp_establish pmdp_establish
619 static inline pmd_t pmdp_establish(struct vm_area_struct *vma,
620 				unsigned long address, pmd_t *pmdp, pmd_t pmd)
621 {
622 	return __pmd(atomic_long_xchg((atomic_long_t *)pmdp, pmd_val(pmd)));
623 }
624 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
625 
626 /*
627  * Encode and decode a swap entry
628  *
629  * Format of swap PTE:
630  *	bit            0:	_PAGE_PRESENT (zero)
631  *	bit            1:	_PAGE_PROT_NONE (zero)
632  *	bits      2 to 6:	swap type
633  *	bits 7 to XLEN-1:	swap offset
634  */
635 #define __SWP_TYPE_SHIFT	2
636 #define __SWP_TYPE_BITS		5
637 #define __SWP_TYPE_MASK		((1UL << __SWP_TYPE_BITS) - 1)
638 #define __SWP_OFFSET_SHIFT	(__SWP_TYPE_BITS + __SWP_TYPE_SHIFT)
639 
640 #define MAX_SWAPFILES_CHECK()	\
641 	BUILD_BUG_ON(MAX_SWAPFILES_SHIFT > __SWP_TYPE_BITS)
642 
643 #define __swp_type(x)	(((x).val >> __SWP_TYPE_SHIFT) & __SWP_TYPE_MASK)
644 #define __swp_offset(x)	((x).val >> __SWP_OFFSET_SHIFT)
645 #define __swp_entry(type, offset) ((swp_entry_t) \
646 	{ ((type) << __SWP_TYPE_SHIFT) | ((offset) << __SWP_OFFSET_SHIFT) })
647 
648 #define __pte_to_swp_entry(pte)	((swp_entry_t) { pte_val(pte) })
649 #define __swp_entry_to_pte(x)	((pte_t) { (x).val })
650 
651 /*
652  * In the RV64 Linux scheme, we give the user half of the virtual-address space
653  * and give the kernel the other (upper) half.
654  */
655 #ifdef CONFIG_64BIT
656 #define KERN_VIRT_START	(-(BIT(CONFIG_VA_BITS)) + TASK_SIZE)
657 #else
658 #define KERN_VIRT_START	FIXADDR_START
659 #endif
660 
661 /*
662  * Task size is 0x4000000000 for RV64 or 0x9fc00000 for RV32.
663  * Note that PGDIR_SIZE must evenly divide TASK_SIZE.
664  */
665 #ifdef CONFIG_64BIT
666 #define TASK_SIZE (PGDIR_SIZE * PTRS_PER_PGD / 2)
667 #else
668 #define TASK_SIZE FIXADDR_START
669 #endif
670 
671 #else /* CONFIG_MMU */
672 
673 #define PAGE_SHARED		__pgprot(0)
674 #define PAGE_KERNEL		__pgprot(0)
675 #define swapper_pg_dir		NULL
676 #define TASK_SIZE		0xffffffffUL
677 #define VMALLOC_START		0
678 #define VMALLOC_END		TASK_SIZE
679 
680 #endif /* !CONFIG_MMU */
681 
682 #define kern_addr_valid(addr)   (1) /* FIXME */
683 
684 extern char _start[];
685 extern void *_dtb_early_va;
686 extern uintptr_t _dtb_early_pa;
687 #if defined(CONFIG_XIP_KERNEL) && defined(CONFIG_MMU)
688 #define dtb_early_va	(*(void **)XIP_FIXUP(&_dtb_early_va))
689 #define dtb_early_pa	(*(uintptr_t *)XIP_FIXUP(&_dtb_early_pa))
690 #else
691 #define dtb_early_va	_dtb_early_va
692 #define dtb_early_pa	_dtb_early_pa
693 #endif /* CONFIG_XIP_KERNEL */
694 
695 void paging_init(void);
696 void misc_mem_init(void);
697 
698 /*
699  * ZERO_PAGE is a global shared page that is always zero,
700  * used for zero-mapped memory areas, etc.
701  */
702 extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)];
703 #define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
704 
705 #endif /* !__ASSEMBLY__ */
706 
707 #endif /* _ASM_RISCV_PGTABLE_H */
708