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 extern unsigned long end_iomem;
49 
50 #define VMALLOC_OFFSET	(__va_space)
51 #define VMALLOC_START ((end_iomem + VMALLOC_OFFSET) & ~(VMALLOC_OFFSET-1))
52 #define VMALLOC_END	(TASK_SIZE-2*PAGE_SIZE)
53 #define MODULES_VADDR	VMALLOC_START
54 #define MODULES_END	VMALLOC_END
55 
56 #define _PAGE_TABLE	(_PAGE_PRESENT | _PAGE_RW | _PAGE_USER | _PAGE_ACCESSED | _PAGE_DIRTY)
57 #define _KERNPG_TABLE	(_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED | _PAGE_DIRTY)
58 #define _PAGE_CHG_MASK	(PAGE_MASK | _PAGE_ACCESSED | _PAGE_DIRTY)
59 #define __PAGE_KERNEL_EXEC                                              \
60 	 (_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | _PAGE_ACCESSED)
61 #define PAGE_NONE	__pgprot(_PAGE_PROTNONE | _PAGE_ACCESSED)
62 #define PAGE_SHARED	__pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_USER | _PAGE_ACCESSED)
63 #define PAGE_COPY	__pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_ACCESSED)
64 #define PAGE_READONLY	__pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_ACCESSED)
65 #define PAGE_KERNEL	__pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | _PAGE_ACCESSED)
66 #define PAGE_KERNEL_EXEC	__pgprot(__PAGE_KERNEL_EXEC)
67 
68 /*
69  * The i386 can't do page protection for execute, and considers that the same
70  * are read.
71  * Also, write permissions imply read permissions. This is the closest we can
72  * get..
73  */
74 
75 /*
76  * ZERO_PAGE is a global shared page that is always zero: used
77  * for zero-mapped memory areas etc..
78  */
79 #define ZERO_PAGE(vaddr) virt_to_page(empty_zero_page)
80 
81 #define pte_clear(mm, addr, xp) pte_set_val(*(xp), (phys_t) 0, __pgprot(_PAGE_NEEDSYNC))
82 
83 #define pmd_none(x)	(!((unsigned long)pmd_val(x) & ~_PAGE_NEEDSYNC))
84 #define	pmd_bad(x)	((pmd_val(x) & (~PAGE_MASK & ~_PAGE_USER)) != _KERNPG_TABLE)
85 
86 #define pmd_present(x)	(pmd_val(x) & _PAGE_PRESENT)
87 #define pmd_clear(xp)	do { pmd_val(*(xp)) = _PAGE_NEEDSYNC; } while (0)
88 
89 #define pmd_needsync(x)   (pmd_val(x) & _PAGE_NEEDSYNC)
90 #define pmd_mkuptodate(x) (pmd_val(x) &= ~_PAGE_NEEDSYNC)
91 
92 #define pud_needsync(x)   (pud_val(x) & _PAGE_NEEDSYNC)
93 #define pud_mkuptodate(x) (pud_val(x) &= ~_PAGE_NEEDSYNC)
94 
95 #define p4d_needsync(x)   (p4d_val(x) & _PAGE_NEEDSYNC)
96 #define p4d_mkuptodate(x) (p4d_val(x) &= ~_PAGE_NEEDSYNC)
97 
98 #define pmd_pfn(pmd) (pmd_val(pmd) >> PAGE_SHIFT)
99 #define pmd_page(pmd) phys_to_page(pmd_val(pmd) & PAGE_MASK)
100 
101 #define pte_page(x) pfn_to_page(pte_pfn(x))
102 
103 #define pte_present(x)	pte_get_bits(x, (_PAGE_PRESENT | _PAGE_PROTNONE))
104 
105 /*
106  * =================================
107  * Flags checking section.
108  * =================================
109  */
110 
111 static inline int pte_none(pte_t pte)
112 {
113 	return pte_is_zero(pte);
114 }
115 
116 /*
117  * The following only work if pte_present() is true.
118  * Undefined behaviour if not..
119  */
120 static inline int pte_read(pte_t pte)
121 {
122 	return((pte_get_bits(pte, _PAGE_USER)) &&
123 	       !(pte_get_bits(pte, _PAGE_PROTNONE)));
124 }
125 
126 static inline int pte_exec(pte_t pte){
127 	return((pte_get_bits(pte, _PAGE_USER)) &&
128 	       !(pte_get_bits(pte, _PAGE_PROTNONE)));
129 }
130 
131 static inline int pte_write(pte_t pte)
132 {
133 	return((pte_get_bits(pte, _PAGE_RW)) &&
134 	       !(pte_get_bits(pte, _PAGE_PROTNONE)));
135 }
136 
137 static inline int pte_dirty(pte_t pte)
138 {
139 	return pte_get_bits(pte, _PAGE_DIRTY);
140 }
141 
142 static inline int pte_young(pte_t pte)
143 {
144 	return pte_get_bits(pte, _PAGE_ACCESSED);
145 }
146 
147 static inline int pte_needsync(pte_t pte)
148 {
149 	return pte_get_bits(pte, _PAGE_NEEDSYNC);
150 }
151 
152 /*
153  * =================================
154  * Flags setting section.
155  * =================================
156  */
157 
158 static inline pte_t pte_mkclean(pte_t pte)
159 {
160 	pte_clear_bits(pte, _PAGE_DIRTY);
161 	return(pte);
162 }
163 
164 static inline pte_t pte_mkold(pte_t pte)
165 {
166 	pte_clear_bits(pte, _PAGE_ACCESSED);
167 	return(pte);
168 }
169 
170 static inline pte_t pte_wrprotect(pte_t pte)
171 {
172 	pte_clear_bits(pte, _PAGE_RW);
173 	return pte;
174 }
175 
176 static inline pte_t pte_mkread(pte_t pte)
177 {
178 	pte_set_bits(pte, _PAGE_USER);
179 	return pte;
180 }
181 
182 static inline pte_t pte_mkdirty(pte_t pte)
183 {
184 	pte_set_bits(pte, _PAGE_DIRTY);
185 	return(pte);
186 }
187 
188 static inline pte_t pte_mkyoung(pte_t pte)
189 {
190 	pte_set_bits(pte, _PAGE_ACCESSED);
191 	return(pte);
192 }
193 
194 static inline pte_t pte_mkwrite_novma(pte_t pte)
195 {
196 	pte_set_bits(pte, _PAGE_RW);
197 	return pte;
198 }
199 
200 static inline pte_t pte_mkuptodate(pte_t pte)
201 {
202 	pte_clear_bits(pte, _PAGE_NEEDSYNC);
203 	return pte;
204 }
205 
206 static inline pte_t pte_mkneedsync(pte_t pte)
207 {
208 	pte_set_bits(pte, _PAGE_NEEDSYNC);
209 	return(pte);
210 }
211 
212 static inline void set_pte(pte_t *pteptr, pte_t pteval)
213 {
214 	pte_copy(*pteptr, pteval);
215 
216 	/* If it's a swap entry, it needs to be marked _PAGE_NEEDSYNC so
217 	 * update_pte_range knows to unmap it.
218 	 */
219 
220 	*pteptr = pte_mkneedsync(*pteptr);
221 }
222 
223 #define PFN_PTE_SHIFT		PAGE_SHIFT
224 
225 static inline void um_tlb_mark_sync(struct mm_struct *mm, unsigned long start,
226 				    unsigned long end)
227 {
228 	if (!mm->context.sync_tlb_range_to) {
229 		mm->context.sync_tlb_range_from = start;
230 		mm->context.sync_tlb_range_to = end;
231 	} else {
232 		if (start < mm->context.sync_tlb_range_from)
233 			mm->context.sync_tlb_range_from = start;
234 		if (end > mm->context.sync_tlb_range_to)
235 			mm->context.sync_tlb_range_to = end;
236 	}
237 }
238 
239 #define set_ptes set_ptes
240 static inline void set_ptes(struct mm_struct *mm, unsigned long addr,
241 			    pte_t *ptep, pte_t pte, int nr)
242 {
243 	/* Basically the default implementation */
244 	size_t length = nr * PAGE_SIZE;
245 
246 	for (;;) {
247 		set_pte(ptep, pte);
248 		if (--nr == 0)
249 			break;
250 		ptep++;
251 		pte = __pte(pte_val(pte) + (nr << PFN_PTE_SHIFT));
252 	}
253 
254 	um_tlb_mark_sync(mm, addr, addr + length);
255 }
256 
257 #define __HAVE_ARCH_PTE_SAME
258 static inline int pte_same(pte_t pte_a, pte_t pte_b)
259 {
260 	return !((pte_val(pte_a) ^ pte_val(pte_b)) & ~_PAGE_NEEDSYNC);
261 }
262 
263 #define __virt_to_page(virt) phys_to_page(__pa(virt))
264 #define virt_to_page(addr) __virt_to_page((const unsigned long) addr)
265 
266 static inline pte_t pfn_pte(unsigned long pfn, pgprot_t pgprot)
267 {
268 	pte_t pte;
269 
270 	pte_set_val(pte, pfn_to_phys(pfn), pgprot);
271 
272 	return pte;
273 }
274 
275 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
276 {
277 	pte_set_val(pte, (pte_val(pte) & _PAGE_CHG_MASK), newprot);
278 	return pte;
279 }
280 
281 /*
282  * the pmd page can be thought of an array like this: pmd_t[PTRS_PER_PMD]
283  *
284  * this macro returns the index of the entry in the pmd page which would
285  * control the given virtual address
286  */
287 #define pmd_page_vaddr(pmd) ((unsigned long) __va(pmd_val(pmd) & PAGE_MASK))
288 
289 struct mm_struct;
290 extern pte_t *virt_to_pte(struct mm_struct *mm, unsigned long addr);
291 
292 #define update_mmu_cache(vma,address,ptep) do {} while (0)
293 #define update_mmu_cache_range(vmf, vma, address, ptep, nr) do {} while (0)
294 
295 /*
296  * Encode/decode swap entries and swap PTEs. Swap PTEs are all PTEs that
297  * are !pte_none() && !pte_present().
298  *
299  * Format of swap PTEs:
300  *
301  *   3 3 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1
302  *   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
303  *   <--------------- offset ----------------> E < type -> 0 0 0 1 0
304  *
305  *   E is the exclusive marker that is not stored in swap entries.
306  *   _PAGE_NEEDSYNC (bit 1) is always set to 1 in set_pte().
307  */
308 #define __swp_type(x)			(((x).val >> 5) & 0x1f)
309 #define __swp_offset(x)			((x).val >> 11)
310 
311 #define __swp_entry(type, offset) \
312 	((swp_entry_t) { (((type) & 0x1f) << 5) | ((offset) << 11) })
313 #define __pte_to_swp_entry(pte) \
314 	((swp_entry_t) { pte_val(pte_mkuptodate(pte)) })
315 #define __swp_entry_to_pte(x)		((pte_t) { (x).val })
316 
317 static inline int pte_swp_exclusive(pte_t pte)
318 {
319 	return pte_get_bits(pte, _PAGE_SWP_EXCLUSIVE);
320 }
321 
322 static inline pte_t pte_swp_mkexclusive(pte_t pte)
323 {
324 	pte_set_bits(pte, _PAGE_SWP_EXCLUSIVE);
325 	return pte;
326 }
327 
328 static inline pte_t pte_swp_clear_exclusive(pte_t pte)
329 {
330 	pte_clear_bits(pte, _PAGE_SWP_EXCLUSIVE);
331 	return pte;
332 }
333 
334 #endif
335