xref: /linux/arch/um/include/asm/pgtable.h (revision d1895c15fc7d90a615bc8c455feb02acaf08ef1e) 
1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3  * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
4  * Copyright 2003 PathScale, Inc.
5  * Derived from include/asm-i386/pgtable.h
6  */
7 
8 #ifndef __UM_PGTABLE_H
9 #define __UM_PGTABLE_H
10 
11 #include <asm/page.h>
12 #include <linux/mm_types.h>
13 
14 #define _PAGE_PRESENT	0x001
15 #define _PAGE_NEEDSYNC	0x002
16 #define _PAGE_RW	0x020
17 #define _PAGE_USER	0x040
18 #define _PAGE_ACCESSED	0x080
19 #define _PAGE_DIRTY	0x100
20 /* If _PAGE_PRESENT is clear, we use these: */
21 #define _PAGE_PROTNONE	0x010	/* if the user mapped it with PROT_NONE;
22 				   pte_present gives true */
23 
24 /* We borrow bit 10 to store the exclusive marker in swap PTEs. */
25 #define _PAGE_SWP_EXCLUSIVE	0x400
26 
27 #if CONFIG_PGTABLE_LEVELS == 4
28 #include <asm/pgtable-4level.h>
29 #elif CONFIG_PGTABLE_LEVELS == 2
30 #include <asm/pgtable-2level.h>
31 #else
32 #error "Unsupported number of page table levels"
33 #endif
34 
35 extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
36 
37 /* zero page used for uninitialized stuff */
38 extern unsigned long *empty_zero_page;
39 
40 /* Just any arbitrary offset to the start of the vmalloc VM area: the
41  * current 8MB value just means that there will be a 8MB "hole" after the
42  * physical memory until the kernel virtual memory starts.  That means that
43  * any out-of-bounds memory accesses will hopefully be caught.
44  * The vmalloc() routines leaves a hole of 4kB between each vmalloced
45  * area for the same reason. ;)
46  */
47 
48 #ifndef COMPILE_OFFSETS
49 #include <as-layout.h> /* for high_physmem */
50 #endif
51 
52 #define VMALLOC_OFFSET	(__va_space)
53 #define VMALLOC_START	((high_physmem + VMALLOC_OFFSET) & ~(VMALLOC_OFFSET-1))
54 #define VMALLOC_END	(TASK_SIZE-2*PAGE_SIZE)
55 #define MODULES_VADDR	VMALLOC_START
56 #define MODULES_END	VMALLOC_END
57 
58 #define _PAGE_TABLE	(_PAGE_PRESENT | _PAGE_RW | _PAGE_USER | _PAGE_ACCESSED | _PAGE_DIRTY)
59 #define _KERNPG_TABLE	(_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED | _PAGE_DIRTY)
60 #define _PAGE_CHG_MASK	(PAGE_MASK | _PAGE_ACCESSED | _PAGE_DIRTY)
61 #define __PAGE_KERNEL_EXEC                                              \
62 	 (_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | _PAGE_ACCESSED)
63 #define PAGE_NONE	__pgprot(_PAGE_PROTNONE | _PAGE_ACCESSED)
64 #define PAGE_SHARED	__pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_USER | _PAGE_ACCESSED)
65 #define PAGE_COPY	__pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_ACCESSED)
66 #define PAGE_READONLY	__pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_ACCESSED)
67 #define PAGE_KERNEL	__pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | _PAGE_ACCESSED)
68 #define PAGE_KERNEL_EXEC	__pgprot(__PAGE_KERNEL_EXEC)
69 
70 /*
71  * The i386 can't do page protection for execute, and considers that the same
72  * are read.
73  * Also, write permissions imply read permissions. This is the closest we can
74  * get..
75  */
76 
77 /*
78  * ZERO_PAGE is a global shared page that is always zero: used
79  * for zero-mapped memory areas etc..
80  */
81 #define ZERO_PAGE(vaddr) virt_to_page(empty_zero_page)
82 
83 #define pte_clear(mm, addr, xp) pte_set_val(*(xp), (phys_t) 0, __pgprot(_PAGE_NEEDSYNC))
84 
85 #define pmd_none(x)	(!((unsigned long)pmd_val(x) & ~_PAGE_NEEDSYNC))
86 #define	pmd_bad(x)	((pmd_val(x) & (~PAGE_MASK & ~_PAGE_USER)) != _KERNPG_TABLE)
87 
88 #define pmd_present(x)	(pmd_val(x) & _PAGE_PRESENT)
89 #define pmd_clear(xp)	do { pmd_val(*(xp)) = _PAGE_NEEDSYNC; } while (0)
90 
91 #define pmd_needsync(x)   (pmd_val(x) & _PAGE_NEEDSYNC)
92 #define pmd_mkuptodate(x) (pmd_val(x) &= ~_PAGE_NEEDSYNC)
93 
94 #define pud_needsync(x)   (pud_val(x) & _PAGE_NEEDSYNC)
95 #define pud_mkuptodate(x) (pud_val(x) &= ~_PAGE_NEEDSYNC)
96 
97 #define p4d_needsync(x)   (p4d_val(x) & _PAGE_NEEDSYNC)
98 #define p4d_mkuptodate(x) (p4d_val(x) &= ~_PAGE_NEEDSYNC)
99 
100 #define pmd_pfn(pmd) (pmd_val(pmd) >> PAGE_SHIFT)
101 #define pmd_page(pmd) phys_to_page(pmd_val(pmd) & PAGE_MASK)
102 
103 #define pte_page(x) pfn_to_page(pte_pfn(x))
104 
105 #define pte_present(x)	pte_get_bits(x, (_PAGE_PRESENT | _PAGE_PROTNONE))
106 
107 /*
108  * =================================
109  * Flags checking section.
110  * =================================
111  */
112 
113 static inline int pte_none(pte_t pte)
114 {
115 	return pte_is_zero(pte);
116 }
117 
118 /*
119  * The following only work if pte_present() is true.
120  * Undefined behaviour if not..
121  */
122 static inline int pte_read(pte_t pte)
123 {
124 	return !pte_get_bits(pte, _PAGE_PROTNONE);
125 }
126 
127 static inline int pte_exec(pte_t pte)
128 {
129 	return !pte_get_bits(pte, _PAGE_PROTNONE);
130 }
131 
132 static inline int pte_write(pte_t pte)
133 {
134 	return((pte_get_bits(pte, _PAGE_RW)) &&
135 	       !(pte_get_bits(pte, _PAGE_PROTNONE)));
136 }
137 
138 static inline int pte_dirty(pte_t pte)
139 {
140 	return pte_get_bits(pte, _PAGE_DIRTY);
141 }
142 
143 static inline int pte_young(pte_t pte)
144 {
145 	return pte_get_bits(pte, _PAGE_ACCESSED);
146 }
147 
148 static inline int pte_needsync(pte_t pte)
149 {
150 	return pte_get_bits(pte, _PAGE_NEEDSYNC);
151 }
152 
153 /*
154  * =================================
155  * Flags setting section.
156  * =================================
157  */
158 
159 static inline pte_t pte_mkclean(pte_t pte)
160 {
161 	pte_clear_bits(pte, _PAGE_DIRTY);
162 	return(pte);
163 }
164 
165 static inline pte_t pte_mkold(pte_t pte)
166 {
167 	pte_clear_bits(pte, _PAGE_ACCESSED);
168 	return(pte);
169 }
170 
171 static inline pte_t pte_wrprotect(pte_t pte)
172 {
173 	pte_clear_bits(pte, _PAGE_RW);
174 	return pte;
175 }
176 
177 static inline pte_t pte_mkread(pte_t pte)
178 {
179 	pte_set_bits(pte, _PAGE_USER);
180 	return pte;
181 }
182 
183 static inline pte_t pte_mkdirty(pte_t pte)
184 {
185 	pte_set_bits(pte, _PAGE_DIRTY);
186 	return(pte);
187 }
188 
189 static inline pte_t pte_mkyoung(pte_t pte)
190 {
191 	pte_set_bits(pte, _PAGE_ACCESSED);
192 	return(pte);
193 }
194 
195 static inline pte_t pte_mkwrite_novma(pte_t pte)
196 {
197 	pte_set_bits(pte, _PAGE_RW);
198 	return pte;
199 }
200 
201 static inline pte_t pte_mkuptodate(pte_t pte)
202 {
203 	pte_clear_bits(pte, _PAGE_NEEDSYNC);
204 	return pte;
205 }
206 
207 static inline pte_t pte_mkneedsync(pte_t pte)
208 {
209 	pte_set_bits(pte, _PAGE_NEEDSYNC);
210 	return(pte);
211 }
212 
213 static inline void set_pte(pte_t *pteptr, pte_t pteval)
214 {
215 	pte_copy(*pteptr, pteval);
216 
217 	/* If it's a swap entry, it needs to be marked _PAGE_NEEDSYNC so
218 	 * update_pte_range knows to unmap it.
219 	 */
220 
221 	*pteptr = pte_mkneedsync(*pteptr);
222 }
223 
224 #define PFN_PTE_SHIFT		PAGE_SHIFT
225 
226 static inline void um_tlb_mark_sync(struct mm_struct *mm, unsigned long start,
227 				    unsigned long end)
228 {
229 	guard(spinlock_irqsave)(&mm->context.sync_tlb_lock);
230 
231 	if (!mm->context.sync_tlb_range_to) {
232 		mm->context.sync_tlb_range_from = start;
233 		mm->context.sync_tlb_range_to = end;
234 	} else {
235 		if (start < mm->context.sync_tlb_range_from)
236 			mm->context.sync_tlb_range_from = start;
237 		if (end > mm->context.sync_tlb_range_to)
238 			mm->context.sync_tlb_range_to = end;
239 	}
240 }
241 
242 #define set_ptes set_ptes
243 static inline void set_ptes(struct mm_struct *mm, unsigned long addr,
244 			    pte_t *ptep, pte_t pte, int nr)
245 {
246 	/* Basically the default implementation */
247 	size_t length = nr * PAGE_SIZE;
248 
249 	for (;;) {
250 		set_pte(ptep, pte);
251 		if (--nr == 0)
252 			break;
253 		ptep++;
254 		pte = __pte(pte_val(pte) + (nr << PFN_PTE_SHIFT));
255 	}
256 
257 	um_tlb_mark_sync(mm, addr, addr + length);
258 }
259 
260 #define __HAVE_ARCH_PTE_SAME
261 static inline int pte_same(pte_t pte_a, pte_t pte_b)
262 {
263 	return !((pte_val(pte_a) ^ pte_val(pte_b)) & ~_PAGE_NEEDSYNC);
264 }
265 
266 #define __virt_to_page(virt) phys_to_page(__pa(virt))
267 #define virt_to_page(addr) __virt_to_page((const unsigned long) addr)
268 
269 static inline pte_t pfn_pte(unsigned long pfn, pgprot_t pgprot)
270 {
271 	pte_t pte;
272 
273 	pte_set_val(pte, pfn_to_phys(pfn), pgprot);
274 
275 	return pte;
276 }
277 
278 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
279 {
280 	pte_set_val(pte, (pte_val(pte) & _PAGE_CHG_MASK), newprot);
281 	return pte;
282 }
283 
284 /*
285  * the pmd page can be thought of an array like this: pmd_t[PTRS_PER_PMD]
286  *
287  * this macro returns the index of the entry in the pmd page which would
288  * control the given virtual address
289  */
290 #define pmd_page_vaddr(pmd) ((unsigned long) __va(pmd_val(pmd) & PAGE_MASK))
291 
292 struct mm_struct;
293 extern pte_t *virt_to_pte(struct mm_struct *mm, unsigned long addr);
294 
295 #define update_mmu_cache(vma,address,ptep) do {} while (0)
296 #define update_mmu_cache_range(vmf, vma, address, ptep, nr) do {} while (0)
297 
298 /*
299  * Encode/decode swap entries and swap PTEs. Swap PTEs are all PTEs that
300  * are !pte_none() && !pte_present().
301  *
302  * Format of swap PTEs:
303  *
304  *   3 3 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1
305  *   1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0
306  *   <--------------- offset ----------------> E < type -> 0 0 0 1 0
307  *
308  *   E is the exclusive marker that is not stored in swap entries.
309  *   _PAGE_NEEDSYNC (bit 1) is always set to 1 in set_pte().
310  */
311 #define __swp_type(x)			(((x).val >> 5) & 0x1f)
312 #define __swp_offset(x)			((x).val >> 11)
313 
314 #define __swp_entry(type, offset) \
315 	((swp_entry_t) { (((type) & 0x1f) << 5) | ((offset) << 11) })
316 #define __pte_to_swp_entry(pte) \
317 	((swp_entry_t) { pte_val(pte_mkuptodate(pte)) })
318 #define __swp_entry_to_pte(x)		((pte_t) { (x).val })
319 
320 static inline bool pte_swp_exclusive(pte_t pte)
321 {
322 	return pte_get_bits(pte, _PAGE_SWP_EXCLUSIVE);
323 }
324 
325 static inline pte_t pte_swp_mkexclusive(pte_t pte)
326 {
327 	pte_set_bits(pte, _PAGE_SWP_EXCLUSIVE);
328 	return pte;
329 }
330 
331 static inline pte_t pte_swp_clear_exclusive(pte_t pte)
332 {
333 	pte_clear_bits(pte, _PAGE_SWP_EXCLUSIVE);
334 	return pte;
335 }
336 
337 #endif
338