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Diffstat (limited to 'arch/arm/include/asm/pgtable.h')
-rw-r--r-- | arch/arm/include/asm/pgtable.h | 401 |
1 files changed, 401 insertions, 0 deletions
diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h new file mode 100644 index 000000000000..8ab060a53ab0 --- /dev/null +++ b/arch/arm/include/asm/pgtable.h | |||
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1 | /* | ||
2 | * arch/arm/include/asm/pgtable.h | ||
3 | * | ||
4 | * Copyright (C) 1995-2002 Russell King | ||
5 | * | ||
6 | * This program is free software; you can redistribute it and/or modify | ||
7 | * it under the terms of the GNU General Public License version 2 as | ||
8 | * published by the Free Software Foundation. | ||
9 | */ | ||
10 | #ifndef _ASMARM_PGTABLE_H | ||
11 | #define _ASMARM_PGTABLE_H | ||
12 | |||
13 | #include <asm-generic/4level-fixup.h> | ||
14 | #include <asm/proc-fns.h> | ||
15 | |||
16 | #ifndef CONFIG_MMU | ||
17 | |||
18 | #include "pgtable-nommu.h" | ||
19 | |||
20 | #else | ||
21 | |||
22 | #include <asm/memory.h> | ||
23 | #include <asm/arch/vmalloc.h> | ||
24 | #include <asm/pgtable-hwdef.h> | ||
25 | |||
26 | /* | ||
27 | * Just any arbitrary offset to the start of the vmalloc VM area: the | ||
28 | * current 8MB value just means that there will be a 8MB "hole" after the | ||
29 | * physical memory until the kernel virtual memory starts. That means that | ||
30 | * any out-of-bounds memory accesses will hopefully be caught. | ||
31 | * The vmalloc() routines leaves a hole of 4kB between each vmalloced | ||
32 | * area for the same reason. ;) | ||
33 | * | ||
34 | * Note that platforms may override VMALLOC_START, but they must provide | ||
35 | * VMALLOC_END. VMALLOC_END defines the (exclusive) limit of this space, | ||
36 | * which may not overlap IO space. | ||
37 | */ | ||
38 | #ifndef VMALLOC_START | ||
39 | #define VMALLOC_OFFSET (8*1024*1024) | ||
40 | #define VMALLOC_START (((unsigned long)high_memory + VMALLOC_OFFSET) & ~(VMALLOC_OFFSET-1)) | ||
41 | #endif | ||
42 | |||
43 | /* | ||
44 | * Hardware-wise, we have a two level page table structure, where the first | ||
45 | * level has 4096 entries, and the second level has 256 entries. Each entry | ||
46 | * is one 32-bit word. Most of the bits in the second level entry are used | ||
47 | * by hardware, and there aren't any "accessed" and "dirty" bits. | ||
48 | * | ||
49 | * Linux on the other hand has a three level page table structure, which can | ||
50 | * be wrapped to fit a two level page table structure easily - using the PGD | ||
51 | * and PTE only. However, Linux also expects one "PTE" table per page, and | ||
52 | * at least a "dirty" bit. | ||
53 | * | ||
54 | * Therefore, we tweak the implementation slightly - we tell Linux that we | ||
55 | * have 2048 entries in the first level, each of which is 8 bytes (iow, two | ||
56 | * hardware pointers to the second level.) The second level contains two | ||
57 | * hardware PTE tables arranged contiguously, followed by Linux versions | ||
58 | * which contain the state information Linux needs. We, therefore, end up | ||
59 | * with 512 entries in the "PTE" level. | ||
60 | * | ||
61 | * This leads to the page tables having the following layout: | ||
62 | * | ||
63 | * pgd pte | ||
64 | * | | | ||
65 | * +--------+ +0 | ||
66 | * | |-----> +------------+ +0 | ||
67 | * +- - - - + +4 | h/w pt 0 | | ||
68 | * | |-----> +------------+ +1024 | ||
69 | * +--------+ +8 | h/w pt 1 | | ||
70 | * | | +------------+ +2048 | ||
71 | * +- - - - + | Linux pt 0 | | ||
72 | * | | +------------+ +3072 | ||
73 | * +--------+ | Linux pt 1 | | ||
74 | * | | +------------+ +4096 | ||
75 | * | ||
76 | * See L_PTE_xxx below for definitions of bits in the "Linux pt", and | ||
77 | * PTE_xxx for definitions of bits appearing in the "h/w pt". | ||
78 | * | ||
79 | * PMD_xxx definitions refer to bits in the first level page table. | ||
80 | * | ||
81 | * The "dirty" bit is emulated by only granting hardware write permission | ||
82 | * iff the page is marked "writable" and "dirty" in the Linux PTE. This | ||
83 | * means that a write to a clean page will cause a permission fault, and | ||
84 | * the Linux MM layer will mark the page dirty via handle_pte_fault(). | ||
85 | * For the hardware to notice the permission change, the TLB entry must | ||
86 | * be flushed, and ptep_set_access_flags() does that for us. | ||
87 | * | ||
88 | * The "accessed" or "young" bit is emulated by a similar method; we only | ||
89 | * allow accesses to the page if the "young" bit is set. Accesses to the | ||
90 | * page will cause a fault, and handle_pte_fault() will set the young bit | ||
91 | * for us as long as the page is marked present in the corresponding Linux | ||
92 | * PTE entry. Again, ptep_set_access_flags() will ensure that the TLB is | ||
93 | * up to date. | ||
94 | * | ||
95 | * However, when the "young" bit is cleared, we deny access to the page | ||
96 | * by clearing the hardware PTE. Currently Linux does not flush the TLB | ||
97 | * for us in this case, which means the TLB will retain the transation | ||
98 | * until either the TLB entry is evicted under pressure, or a context | ||
99 | * switch which changes the user space mapping occurs. | ||
100 | */ | ||
101 | #define PTRS_PER_PTE 512 | ||
102 | #define PTRS_PER_PMD 1 | ||
103 | #define PTRS_PER_PGD 2048 | ||
104 | |||
105 | /* | ||
106 | * PMD_SHIFT determines the size of the area a second-level page table can map | ||
107 | * PGDIR_SHIFT determines what a third-level page table entry can map | ||
108 | */ | ||
109 | #define PMD_SHIFT 21 | ||
110 | #define PGDIR_SHIFT 21 | ||
111 | |||
112 | #define LIBRARY_TEXT_START 0x0c000000 | ||
113 | |||
114 | #ifndef __ASSEMBLY__ | ||
115 | extern void __pte_error(const char *file, int line, unsigned long val); | ||
116 | extern void __pmd_error(const char *file, int line, unsigned long val); | ||
117 | extern void __pgd_error(const char *file, int line, unsigned long val); | ||
118 | |||
119 | #define pte_ERROR(pte) __pte_error(__FILE__, __LINE__, pte_val(pte)) | ||
120 | #define pmd_ERROR(pmd) __pmd_error(__FILE__, __LINE__, pmd_val(pmd)) | ||
121 | #define pgd_ERROR(pgd) __pgd_error(__FILE__, __LINE__, pgd_val(pgd)) | ||
122 | #endif /* !__ASSEMBLY__ */ | ||
123 | |||
124 | #define PMD_SIZE (1UL << PMD_SHIFT) | ||
125 | #define PMD_MASK (~(PMD_SIZE-1)) | ||
126 | #define PGDIR_SIZE (1UL << PGDIR_SHIFT) | ||
127 | #define PGDIR_MASK (~(PGDIR_SIZE-1)) | ||
128 | |||
129 | /* | ||
130 | * This is the lowest virtual address we can permit any user space | ||
131 | * mapping to be mapped at. This is particularly important for | ||
132 | * non-high vector CPUs. | ||
133 | */ | ||
134 | #define FIRST_USER_ADDRESS PAGE_SIZE | ||
135 | |||
136 | #define FIRST_USER_PGD_NR 1 | ||
137 | #define USER_PTRS_PER_PGD ((TASK_SIZE/PGDIR_SIZE) - FIRST_USER_PGD_NR) | ||
138 | |||
139 | /* | ||
140 | * section address mask and size definitions. | ||
141 | */ | ||
142 | #define SECTION_SHIFT 20 | ||
143 | #define SECTION_SIZE (1UL << SECTION_SHIFT) | ||
144 | #define SECTION_MASK (~(SECTION_SIZE-1)) | ||
145 | |||
146 | /* | ||
147 | * ARMv6 supersection address mask and size definitions. | ||
148 | */ | ||
149 | #define SUPERSECTION_SHIFT 24 | ||
150 | #define SUPERSECTION_SIZE (1UL << SUPERSECTION_SHIFT) | ||
151 | #define SUPERSECTION_MASK (~(SUPERSECTION_SIZE-1)) | ||
152 | |||
153 | /* | ||
154 | * "Linux" PTE definitions. | ||
155 | * | ||
156 | * We keep two sets of PTEs - the hardware and the linux version. | ||
157 | * This allows greater flexibility in the way we map the Linux bits | ||
158 | * onto the hardware tables, and allows us to have YOUNG and DIRTY | ||
159 | * bits. | ||
160 | * | ||
161 | * The PTE table pointer refers to the hardware entries; the "Linux" | ||
162 | * entries are stored 1024 bytes below. | ||
163 | */ | ||
164 | #define L_PTE_PRESENT (1 << 0) | ||
165 | #define L_PTE_FILE (1 << 1) /* only when !PRESENT */ | ||
166 | #define L_PTE_YOUNG (1 << 1) | ||
167 | #define L_PTE_BUFFERABLE (1 << 2) /* matches PTE */ | ||
168 | #define L_PTE_CACHEABLE (1 << 3) /* matches PTE */ | ||
169 | #define L_PTE_USER (1 << 4) | ||
170 | #define L_PTE_WRITE (1 << 5) | ||
171 | #define L_PTE_EXEC (1 << 6) | ||
172 | #define L_PTE_DIRTY (1 << 7) | ||
173 | #define L_PTE_SHARED (1 << 10) /* shared(v6), coherent(xsc3) */ | ||
174 | |||
175 | #ifndef __ASSEMBLY__ | ||
176 | |||
177 | /* | ||
178 | * The pgprot_* and protection_map entries will be fixed up in runtime | ||
179 | * to include the cachable and bufferable bits based on memory policy, | ||
180 | * as well as any architecture dependent bits like global/ASID and SMP | ||
181 | * shared mapping bits. | ||
182 | */ | ||
183 | #define _L_PTE_DEFAULT L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_CACHEABLE | L_PTE_BUFFERABLE | ||
184 | #define _L_PTE_READ L_PTE_USER | L_PTE_EXEC | ||
185 | |||
186 | extern pgprot_t pgprot_user; | ||
187 | extern pgprot_t pgprot_kernel; | ||
188 | |||
189 | #define PAGE_NONE pgprot_user | ||
190 | #define PAGE_COPY __pgprot(pgprot_val(pgprot_user) | _L_PTE_READ) | ||
191 | #define PAGE_SHARED __pgprot(pgprot_val(pgprot_user) | _L_PTE_READ | \ | ||
192 | L_PTE_WRITE) | ||
193 | #define PAGE_READONLY __pgprot(pgprot_val(pgprot_user) | _L_PTE_READ) | ||
194 | #define PAGE_KERNEL pgprot_kernel | ||
195 | |||
196 | #define __PAGE_NONE __pgprot(_L_PTE_DEFAULT) | ||
197 | #define __PAGE_COPY __pgprot(_L_PTE_DEFAULT | _L_PTE_READ) | ||
198 | #define __PAGE_SHARED __pgprot(_L_PTE_DEFAULT | _L_PTE_READ | L_PTE_WRITE) | ||
199 | #define __PAGE_READONLY __pgprot(_L_PTE_DEFAULT | _L_PTE_READ) | ||
200 | |||
201 | #endif /* __ASSEMBLY__ */ | ||
202 | |||
203 | /* | ||
204 | * The table below defines the page protection levels that we insert into our | ||
205 | * Linux page table version. These get translated into the best that the | ||
206 | * architecture can perform. Note that on most ARM hardware: | ||
207 | * 1) We cannot do execute protection | ||
208 | * 2) If we could do execute protection, then read is implied | ||
209 | * 3) write implies read permissions | ||
210 | */ | ||
211 | #define __P000 __PAGE_NONE | ||
212 | #define __P001 __PAGE_READONLY | ||
213 | #define __P010 __PAGE_COPY | ||
214 | #define __P011 __PAGE_COPY | ||
215 | #define __P100 __PAGE_READONLY | ||
216 | #define __P101 __PAGE_READONLY | ||
217 | #define __P110 __PAGE_COPY | ||
218 | #define __P111 __PAGE_COPY | ||
219 | |||
220 | #define __S000 __PAGE_NONE | ||
221 | #define __S001 __PAGE_READONLY | ||
222 | #define __S010 __PAGE_SHARED | ||
223 | #define __S011 __PAGE_SHARED | ||
224 | #define __S100 __PAGE_READONLY | ||
225 | #define __S101 __PAGE_READONLY | ||
226 | #define __S110 __PAGE_SHARED | ||
227 | #define __S111 __PAGE_SHARED | ||
228 | |||
229 | #ifndef __ASSEMBLY__ | ||
230 | /* | ||
231 | * ZERO_PAGE is a global shared page that is always zero: used | ||
232 | * for zero-mapped memory areas etc.. | ||
233 | */ | ||
234 | extern struct page *empty_zero_page; | ||
235 | #define ZERO_PAGE(vaddr) (empty_zero_page) | ||
236 | |||
237 | #define pte_pfn(pte) (pte_val(pte) >> PAGE_SHIFT) | ||
238 | #define pfn_pte(pfn,prot) (__pte(((pfn) << PAGE_SHIFT) | pgprot_val(prot))) | ||
239 | |||
240 | #define pte_none(pte) (!pte_val(pte)) | ||
241 | #define pte_clear(mm,addr,ptep) set_pte_ext(ptep, __pte(0), 0) | ||
242 | #define pte_page(pte) (pfn_to_page(pte_pfn(pte))) | ||
243 | #define pte_offset_kernel(dir,addr) (pmd_page_vaddr(*(dir)) + __pte_index(addr)) | ||
244 | #define pte_offset_map(dir,addr) (pmd_page_vaddr(*(dir)) + __pte_index(addr)) | ||
245 | #define pte_offset_map_nested(dir,addr) (pmd_page_vaddr(*(dir)) + __pte_index(addr)) | ||
246 | #define pte_unmap(pte) do { } while (0) | ||
247 | #define pte_unmap_nested(pte) do { } while (0) | ||
248 | |||
249 | #define set_pte_ext(ptep,pte,ext) cpu_set_pte_ext(ptep,pte,ext) | ||
250 | |||
251 | #define set_pte_at(mm,addr,ptep,pteval) do { \ | ||
252 | set_pte_ext(ptep, pteval, (addr) >= TASK_SIZE ? 0 : PTE_EXT_NG); \ | ||
253 | } while (0) | ||
254 | |||
255 | /* | ||
256 | * The following only work if pte_present() is true. | ||
257 | * Undefined behaviour if not.. | ||
258 | */ | ||
259 | #define pte_present(pte) (pte_val(pte) & L_PTE_PRESENT) | ||
260 | #define pte_write(pte) (pte_val(pte) & L_PTE_WRITE) | ||
261 | #define pte_dirty(pte) (pte_val(pte) & L_PTE_DIRTY) | ||
262 | #define pte_young(pte) (pte_val(pte) & L_PTE_YOUNG) | ||
263 | #define pte_special(pte) (0) | ||
264 | |||
265 | /* | ||
266 | * The following only works if pte_present() is not true. | ||
267 | */ | ||
268 | #define pte_file(pte) (pte_val(pte) & L_PTE_FILE) | ||
269 | #define pte_to_pgoff(x) (pte_val(x) >> 2) | ||
270 | #define pgoff_to_pte(x) __pte(((x) << 2) | L_PTE_FILE) | ||
271 | |||
272 | #define PTE_FILE_MAX_BITS 30 | ||
273 | |||
274 | #define PTE_BIT_FUNC(fn,op) \ | ||
275 | static inline pte_t pte_##fn(pte_t pte) { pte_val(pte) op; return pte; } | ||
276 | |||
277 | PTE_BIT_FUNC(wrprotect, &= ~L_PTE_WRITE); | ||
278 | PTE_BIT_FUNC(mkwrite, |= L_PTE_WRITE); | ||
279 | PTE_BIT_FUNC(mkclean, &= ~L_PTE_DIRTY); | ||
280 | PTE_BIT_FUNC(mkdirty, |= L_PTE_DIRTY); | ||
281 | PTE_BIT_FUNC(mkold, &= ~L_PTE_YOUNG); | ||
282 | PTE_BIT_FUNC(mkyoung, |= L_PTE_YOUNG); | ||
283 | |||
284 | static inline pte_t pte_mkspecial(pte_t pte) { return pte; } | ||
285 | |||
286 | /* | ||
287 | * Mark the prot value as uncacheable and unbufferable. | ||
288 | */ | ||
289 | #define pgprot_noncached(prot) __pgprot(pgprot_val(prot) & ~(L_PTE_CACHEABLE | L_PTE_BUFFERABLE)) | ||
290 | #define pgprot_writecombine(prot) __pgprot(pgprot_val(prot) & ~L_PTE_CACHEABLE) | ||
291 | |||
292 | #define pmd_none(pmd) (!pmd_val(pmd)) | ||
293 | #define pmd_present(pmd) (pmd_val(pmd)) | ||
294 | #define pmd_bad(pmd) (pmd_val(pmd) & 2) | ||
295 | |||
296 | #define copy_pmd(pmdpd,pmdps) \ | ||
297 | do { \ | ||
298 | pmdpd[0] = pmdps[0]; \ | ||
299 | pmdpd[1] = pmdps[1]; \ | ||
300 | flush_pmd_entry(pmdpd); \ | ||
301 | } while (0) | ||
302 | |||
303 | #define pmd_clear(pmdp) \ | ||
304 | do { \ | ||
305 | pmdp[0] = __pmd(0); \ | ||
306 | pmdp[1] = __pmd(0); \ | ||
307 | clean_pmd_entry(pmdp); \ | ||
308 | } while (0) | ||
309 | |||
310 | static inline pte_t *pmd_page_vaddr(pmd_t pmd) | ||
311 | { | ||
312 | unsigned long ptr; | ||
313 | |||
314 | ptr = pmd_val(pmd) & ~(PTRS_PER_PTE * sizeof(void *) - 1); | ||
315 | ptr += PTRS_PER_PTE * sizeof(void *); | ||
316 | |||
317 | return __va(ptr); | ||
318 | } | ||
319 | |||
320 | #define pmd_page(pmd) virt_to_page(__va(pmd_val(pmd))) | ||
321 | |||
322 | /* | ||
323 | * Permanent address of a page. We never have highmem, so this is trivial. | ||
324 | */ | ||
325 | #define pages_to_mb(x) ((x) >> (20 - PAGE_SHIFT)) | ||
326 | |||
327 | /* | ||
328 | * Conversion functions: convert a page and protection to a page entry, | ||
329 | * and a page entry and page directory to the page they refer to. | ||
330 | */ | ||
331 | #define mk_pte(page,prot) pfn_pte(page_to_pfn(page),prot) | ||
332 | |||
333 | /* | ||
334 | * The "pgd_xxx()" functions here are trivial for a folded two-level | ||
335 | * setup: the pgd is never bad, and a pmd always exists (as it's folded | ||
336 | * into the pgd entry) | ||
337 | */ | ||
338 | #define pgd_none(pgd) (0) | ||
339 | #define pgd_bad(pgd) (0) | ||
340 | #define pgd_present(pgd) (1) | ||
341 | #define pgd_clear(pgdp) do { } while (0) | ||
342 | #define set_pgd(pgd,pgdp) do { } while (0) | ||
343 | |||
344 | /* to find an entry in a page-table-directory */ | ||
345 | #define pgd_index(addr) ((addr) >> PGDIR_SHIFT) | ||
346 | |||
347 | #define pgd_offset(mm, addr) ((mm)->pgd+pgd_index(addr)) | ||
348 | |||
349 | /* to find an entry in a kernel page-table-directory */ | ||
350 | #define pgd_offset_k(addr) pgd_offset(&init_mm, addr) | ||
351 | |||
352 | /* Find an entry in the second-level page table.. */ | ||
353 | #define pmd_offset(dir, addr) ((pmd_t *)(dir)) | ||
354 | |||
355 | /* Find an entry in the third-level page table.. */ | ||
356 | #define __pte_index(addr) (((addr) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1)) | ||
357 | |||
358 | static inline pte_t pte_modify(pte_t pte, pgprot_t newprot) | ||
359 | { | ||
360 | const unsigned long mask = L_PTE_EXEC | L_PTE_WRITE | L_PTE_USER; | ||
361 | pte_val(pte) = (pte_val(pte) & ~mask) | (pgprot_val(newprot) & mask); | ||
362 | return pte; | ||
363 | } | ||
364 | |||
365 | extern pgd_t swapper_pg_dir[PTRS_PER_PGD]; | ||
366 | |||
367 | /* Encode and decode a swap entry. | ||
368 | * | ||
369 | * We support up to 32GB of swap on 4k machines | ||
370 | */ | ||
371 | #define __swp_type(x) (((x).val >> 2) & 0x7f) | ||
372 | #define __swp_offset(x) ((x).val >> 9) | ||
373 | #define __swp_entry(type,offset) ((swp_entry_t) { ((type) << 2) | ((offset) << 9) }) | ||
374 | #define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) }) | ||
375 | #define __swp_entry_to_pte(swp) ((pte_t) { (swp).val }) | ||
376 | |||
377 | /* Needs to be defined here and not in linux/mm.h, as it is arch dependent */ | ||
378 | /* FIXME: this is not correct */ | ||
379 | #define kern_addr_valid(addr) (1) | ||
380 | |||
381 | #include <asm-generic/pgtable.h> | ||
382 | |||
383 | /* | ||
384 | * We provide our own arch_get_unmapped_area to cope with VIPT caches. | ||
385 | */ | ||
386 | #define HAVE_ARCH_UNMAPPED_AREA | ||
387 | |||
388 | /* | ||
389 | * remap a physical page `pfn' of size `size' with page protection `prot' | ||
390 | * into virtual address `from' | ||
391 | */ | ||
392 | #define io_remap_pfn_range(vma,from,pfn,size,prot) \ | ||
393 | remap_pfn_range(vma, from, pfn, size, prot) | ||
394 | |||
395 | #define pgtable_cache_init() do { } while (0) | ||
396 | |||
397 | #endif /* !__ASSEMBLY__ */ | ||
398 | |||
399 | #endif /* CONFIG_MMU */ | ||
400 | |||
401 | #endif /* _ASMARM_PGTABLE_H */ | ||