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 <linux/const.h>
14 #include <asm-generic/4level-fixup.h>
15 #include <asm/proc-fns.h>
16
17 #ifndef CONFIG_MMU
18
19 #include "pgtable-nommu.h"
20
21 #else
22
23 #include <asm/memory.h>
24 #include <mach/vmalloc.h>
25 #include <asm/pgtable-hwdef.h>
26
27 /*
28 * Just any arbitrary offset to the start of the vmalloc VM area: the
29 * current 8MB value just means that there will be a 8MB "hole" after the
30 * physical memory until the kernel virtual memory starts. That means that
31 * any out-of-bounds memory accesses will hopefully be caught.
32 * The vmalloc() routines leaves a hole of 4kB between each vmalloced
33 * area for the same reason. ;)
34 *
35 * Note that platforms may override VMALLOC_START, but they must provide
36 * VMALLOC_END. VMALLOC_END defines the (exclusive) limit of this space,
37 * which may not overlap IO space.
38 */
39 #ifndef VMALLOC_START
40 #define VMALLOC_OFFSET (8*1024*1024)
41 #define VMALLOC_START (((unsigned long)high_memory + VMALLOC_OFFSET) & ~(VMALLOC_OFFSET-1))
42 #endif
43
44 /*
45 * Hardware-wise, we have a two level page table structure, where the first
46 * level has 4096 entries, and the second level has 256 entries. Each entry
47 * is one 32-bit word. Most of the bits in the second level entry are used
48 * by hardware, and there aren't any "accessed" and "dirty" bits.
49 *
50 * Linux on the other hand has a three level page table structure, which can
51 * be wrapped to fit a two level page table structure easily - using the PGD
52 * and PTE only. However, Linux also expects one "PTE" table per page, and
53 * at least a "dirty" bit.
54 *
55 * Therefore, we tweak the implementation slightly - we tell Linux that we
56 * have 2048 entries in the first level, each of which is 8 bytes (iow, two
57 * hardware pointers to the second level.) The second level contains two
58 * hardware PTE tables arranged contiguously, preceded by Linux versions
59 * which contain the state information Linux needs. We, therefore, end up
60 * with 512 entries in the "PTE" level.
61 *
62 * This leads to the page tables having the following layout:
63 *
64 * pgd pte
65 * | |
66 * +--------+
67 * | | +------------+ +0
68 * +- - - - + | Linux pt 0 |
69 * | | +------------+ +1024
70 * +--------+ +0 | Linux pt 1 |
71 * | |-----> +------------+ +2048
72 * +- - - - + +4 | h/w pt 0 |
73 * | |-----> +------------+ +3072
74 * +--------+ +8 | h/w pt 1 |
75 * | | +------------+ +4096
76 *
77 * See L_PTE_xxx below for definitions of bits in the "Linux pt", and
78 * PTE_xxx for definitions of bits appearing in the "h/w pt".
79 *
80 * PMD_xxx definitions refer to bits in the first level page table.
81 *
82 * The "dirty" bit is emulated by only granting hardware write permission
83 * iff the page is marked "writable" and "dirty" in the Linux PTE. This
84 * means that a write to a clean page will cause a permission fault, and
85 * the Linux MM layer will mark the page dirty via handle_pte_fault().
86 * For the hardware to notice the permission change, the TLB entry must
87 * be flushed, and ptep_set_access_flags() does that for us.
88 *
89 * The "accessed" or "young" bit is emulated by a similar method; we only
90 * allow accesses to the page if the "young" bit is set. Accesses to the
91 * page will cause a fault, and handle_pte_fault() will set the young bit
92 * for us as long as the page is marked present in the corresponding Linux
93 * PTE entry. Again, ptep_set_access_flags() will ensure that the TLB is
94 * up to date.
95 *
96 * However, when the "young" bit is cleared, we deny access to the page
97 * by clearing the hardware PTE. Currently Linux does not flush the TLB
98 * for us in this case, which means the TLB will retain the transation
99 * until either the TLB entry is evicted under pressure, or a context
100 * switch which changes the user space mapping occurs.
101 */
102 #define PTRS_PER_PTE 512
103 #define PTRS_PER_PMD 1
104 #define PTRS_PER_PGD 2048
105
106 #define PTE_HWTABLE_PTRS (PTRS_PER_PTE)
107 #define PTE_HWTABLE_OFF (PTE_HWTABLE_PTRS * sizeof(pte_t))
108 #define PTE_HWTABLE_SIZE (PTRS_PER_PTE * sizeof(u32))
109
110 /*
111 * PMD_SHIFT determines the size of the area a second-level page table can map
112 * PGDIR_SHIFT determines what a third-level page table entry can map
113 */
114 #define PMD_SHIFT 21
115 #define PGDIR_SHIFT 21
116
117 #define LIBRARY_TEXT_START 0x0c000000
118
119 #ifndef __ASSEMBLY__
120 extern void __pte_error(const char *file, int line, pte_t);
121 extern void __pmd_error(const char *file, int line, pmd_t);
122 extern void __pgd_error(const char *file, int line, pgd_t);
123
124 #define pte_ERROR(pte) __pte_error(__FILE__, __LINE__, pte)
125 #define pmd_ERROR(pmd) __pmd_error(__FILE__, __LINE__, pmd)
126 #define pgd_ERROR(pgd) __pgd_error(__FILE__, __LINE__, pgd)
127 #endif /* !__ASSEMBLY__ */
128
129 #define PMD_SIZE (1UL << PMD_SHIFT)
130 #define PMD_MASK (~(PMD_SIZE-1))
131 #define PGDIR_SIZE (1UL << PGDIR_SHIFT)
132 #define PGDIR_MASK (~(PGDIR_SIZE-1))
133
134 /*
135 * This is the lowest virtual address we can permit any user space
136 * mapping to be mapped at. This is particularly important for
137 * non-high vector CPUs.
138 */
139 #define FIRST_USER_ADDRESS PAGE_SIZE
140
141 #define USER_PTRS_PER_PGD (TASK_SIZE / PGDIR_SIZE)
142
143 /*
144 * section address mask and size definitions.
145 */
146 #define SECTION_SHIFT 20
147 #define SECTION_SIZE (1UL << SECTION_SHIFT)
148 #define SECTION_MASK (~(SECTION_SIZE-1))
149
150 /*
151 * ARMv6 supersection address mask and size definitions.
152 */
153 #define SUPERSECTION_SHIFT 24
154 #define SUPERSECTION_SIZE (1UL << SUPERSECTION_SHIFT)
155 #define SUPERSECTION_MASK (~(SUPERSECTION_SIZE-1))
156
157 /*
158 * "Linux" PTE definitions.
159 *
160 * We keep two sets of PTEs - the hardware and the linux version.
161 * This allows greater flexibility in the way we map the Linux bits
162 * onto the hardware tables, and allows us to have YOUNG and DIRTY
163 * bits.
164 *
165 * The PTE table pointer refers to the hardware entries; the "Linux"
166 * entries are stored 1024 bytes below.
167 */
168 #define L_PTE_PRESENT (_AT(pteval_t, 1) << 0)
169 #define L_PTE_YOUNG (_AT(pteval_t, 1) << 1)
170 #define L_PTE_FILE (_AT(pteval_t, 1) << 2) /* only when !PRESENT */
171 #define L_PTE_DIRTY (_AT(pteval_t, 1) << 6)
172 #define L_PTE_RDONLY (_AT(pteval_t, 1) << 7)
173 #define L_PTE_USER (_AT(pteval_t, 1) << 8)
174 #define L_PTE_XN (_AT(pteval_t, 1) << 9)
175 #define L_PTE_SHARED (_AT(pteval_t, 1) << 10) /* shared(v6), coherent(xsc3) */
176
177 /*
178 * These are the memory types, defined to be compatible with
179 * pre-ARMv6 CPUs cacheable and bufferable bits: XXCB
180 */
181 #define L_PTE_MT_UNCACHED (_AT(pteval_t, 0x00) << 2) /* 0000 */
182 #define L_PTE_MT_BUFFERABLE (_AT(pteval_t, 0x01) << 2) /* 0001 */
183 #define L_PTE_MT_WRITETHROUGH (_AT(pteval_t, 0x02) << 2) /* 0010 */
184 #define L_PTE_MT_WRITEBACK (_AT(pteval_t, 0x03) << 2) /* 0011 */
185 #define L_PTE_MT_MINICACHE (_AT(pteval_t, 0x06) << 2) /* 0110 (sa1100, xscale) */
186 #define L_PTE_MT_WRITEALLOC (_AT(pteval_t, 0x07) << 2) /* 0111 */
187 #define L_PTE_MT_DEV_SHARED (_AT(pteval_t, 0x04) << 2) /* 0100 */
188 #define L_PTE_MT_DEV_NONSHARED (_AT(pteval_t, 0x0c) << 2) /* 1100 */
189 #define L_PTE_MT_DEV_WC (_AT(pteval_t, 0x09) << 2) /* 1001 */
190 #define L_PTE_MT_DEV_CACHED (_AT(pteval_t, 0x0b) << 2) /* 1011 */
191 #define L_PTE_MT_MASK (_AT(pteval_t, 0x0f) << 2)
192
193 #ifndef __ASSEMBLY__
194
195 /*
196 * The pgprot_* and protection_map entries will be fixed up in runtime
197 * to include the cachable and bufferable bits based on memory policy,
198 * as well as any architecture dependent bits like global/ASID and SMP
199 * shared mapping bits.
200 */
201 #define _L_PTE_DEFAULT L_PTE_PRESENT | L_PTE_YOUNG
202
203 extern pgprot_t pgprot_user;
204 extern pgprot_t pgprot_kernel;
205
206 #define _MOD_PROT(p, b) __pgprot(pgprot_val(p) | (b))
207
208 #define PAGE_NONE _MOD_PROT(pgprot_user, L_PTE_XN | L_PTE_RDONLY)
209 #define PAGE_SHARED _MOD_PROT(pgprot_user, L_PTE_USER | L_PTE_XN)
210 #define PAGE_SHARED_EXEC _MOD_PROT(pgprot_user, L_PTE_USER)
211 #define PAGE_COPY _MOD_PROT(pgprot_user, L_PTE_USER | L_PTE_RDONLY | L_PTE_XN)
212 #define PAGE_COPY_EXEC _MOD_PROT(pgprot_user, L_PTE_USER | L_PTE_RDONLY)
213 #define PAGE_READONLY _MOD_PROT(pgprot_user, L_PTE_USER | L_PTE_RDONLY | L_PTE_XN)
214 #define PAGE_READONLY_EXEC _MOD_PROT(pgprot_user, L_PTE_USER | L_PTE_RDONLY)
215 #define PAGE_KERNEL _MOD_PROT(pgprot_kernel, L_PTE_XN)
216 #define PAGE_KERNEL_EXEC pgprot_kernel
217
218 #define __PAGE_NONE __pgprot(_L_PTE_DEFAULT | L_PTE_RDONLY | L_PTE_XN)
219 #define __PAGE_SHARED __pgprot(_L_PTE_DEFAULT | L_PTE_USER | L_PTE_XN)
220 #define __PAGE_SHARED_EXEC __pgprot(_L_PTE_DEFAULT | L_PTE_USER)
221 #define __PAGE_COPY __pgprot(_L_PTE_DEFAULT | L_PTE_USER | L_PTE_RDONLY | L_PTE_XN)
222 #define __PAGE_COPY_EXEC __pgprot(_L_PTE_DEFAULT | L_PTE_USER | L_PTE_RDONLY)
223 #define __PAGE_READONLY __pgprot(_L_PTE_DEFAULT | L_PTE_USER | L_PTE_RDONLY | L_PTE_XN)
224 #define __PAGE_READONLY_EXEC __pgprot(_L_PTE_DEFAULT | L_PTE_USER | L_PTE_RDONLY)
225
226 #define __pgprot_modify(prot,mask,bits) \
227 __pgprot((pgprot_val(prot) & ~(mask)) | (bits))
228
229 #define pgprot_noncached(prot) \
230 __pgprot_modify(prot, L_PTE_MT_MASK, L_PTE_MT_UNCACHED)
231
232 #define pgprot_writecombine(prot) \
233 __pgprot_modify(prot, L_PTE_MT_MASK, L_PTE_MT_BUFFERABLE)
234
235 #ifdef CONFIG_ARM_DMA_MEM_BUFFERABLE
236 #define pgprot_dmacoherent(prot) \
237 __pgprot_modify(prot, L_PTE_MT_MASK, L_PTE_MT_BUFFERABLE | L_PTE_XN)
238 #define __HAVE_PHYS_MEM_ACCESS_PROT
239 struct file;
240 extern pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
241 unsigned long size, pgprot_t vma_prot);
242 #else
243 #define pgprot_dmacoherent(prot) \
244 __pgprot_modify(prot, L_PTE_MT_MASK, L_PTE_MT_UNCACHED | L_PTE_XN)
245 #endif
246
247 #endif /* __ASSEMBLY__ */
248
249 /*
250 * The table below defines the page protection levels that we insert into our
251 * Linux page table version. These get translated into the best that the
252 * architecture can perform. Note that on most ARM hardware:
253 * 1) We cannot do execute protection
254 * 2) If we could do execute protection, then read is implied
255 * 3) write implies read permissions
256 */
257 #define __P000 __PAGE_NONE
258 #define __P001 __PAGE_READONLY
259 #define __P010 __PAGE_COPY
260 #define __P011 __PAGE_COPY
261 #define __P100 __PAGE_READONLY_EXEC
262 #define __P101 __PAGE_READONLY_EXEC
263 #define __P110 __PAGE_COPY_EXEC
264 #define __P111 __PAGE_COPY_EXEC
265
266 #define __S000 __PAGE_NONE
267 #define __S001 __PAGE_READONLY
268 #define __S010 __PAGE_SHARED
269 #define __S011 __PAGE_SHARED
270 #define __S100 __PAGE_READONLY_EXEC
271 #define __S101 __PAGE_READONLY_EXEC
272 #define __S110 __PAGE_SHARED_EXEC
273 #define __S111 __PAGE_SHARED_EXEC
274
275 #ifndef __ASSEMBLY__
276 /*
277 * ZERO_PAGE is a global shared page that is always zero: used
278 * for zero-mapped memory areas etc..
279 */
280 extern struct page *empty_zero_page;
281 #define ZERO_PAGE(vaddr) (empty_zero_page)
282
283
284 extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
285
286 /* to find an entry in a page-table-directory */
287 #define pgd_index(addr) ((addr) >> PGDIR_SHIFT)
288
289 #define pgd_offset(mm, addr) ((mm)->pgd + pgd_index(addr))
290
291 /* to find an entry in a kernel page-table-directory */
292 #define pgd_offset_k(addr) pgd_offset(&init_mm, addr)
293
294 /*
295 * The "pgd_xxx()" functions here are trivial for a folded two-level
296 * setup: the pgd is never bad, and a pmd always exists (as it's folded
297 * into the pgd entry)
298 */
299 #define pgd_none(pgd) (0)
300 #define pgd_bad(pgd) (0)
301 #define pgd_present(pgd) (1)
302 #define pgd_clear(pgdp) do { } while (0)
303 #define set_pgd(pgd,pgdp) do { } while (0)
304 #define set_pud(pud,pudp) do { } while (0)
305
306
307 /* Find an entry in the second-level page table.. */
308 #define pmd_offset(dir, addr) ((pmd_t *)(dir))
309
310 #define pmd_none(pmd) (!pmd_val(pmd))
311 #define pmd_present(pmd) (pmd_val(pmd))
312 #define pmd_bad(pmd) (pmd_val(pmd) & 2)
313
314 #define copy_pmd(pmdpd,pmdps) \
315 do { \
316 pmdpd[0] = pmdps[0]; \
317 pmdpd[1] = pmdps[1]; \
318 flush_pmd_entry(pmdpd); \
319 } while (0)
320
321 #define pmd_clear(pmdp) \
322 do { \
323 pmdp[0] = __pmd(0); \
324 pmdp[1] = __pmd(0); \
325 clean_pmd_entry(pmdp); \
326 } while (0)
327
pmd_page_vaddr(pmd_t pmd)328 static inline pte_t *pmd_page_vaddr(pmd_t pmd)
329 {
330 return __va(pmd_val(pmd) & PAGE_MASK);
331 }
332
333 #define pmd_page(pmd) pfn_to_page(__phys_to_pfn(pmd_val(pmd)))
334
335 /* we don't need complex calculations here as the pmd is folded into the pgd */
336 #define pmd_addr_end(addr,end) (end)
337
338
339 #ifndef CONFIG_HIGHPTE
340 #define __pte_map(pmd) pmd_page_vaddr(*(pmd))
341 #define __pte_unmap(pte) do { } while (0)
342 #else
343 #define __pte_map(pmd) (pte_t *)kmap_atomic(pmd_page(*(pmd)))
344 #define __pte_unmap(pte) kunmap_atomic(pte)
345 #endif
346
347 #define pte_index(addr) (((addr) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
348
349 #define pte_offset_kernel(pmd,addr) (pmd_page_vaddr(*(pmd)) + pte_index(addr))
350
351 #define pte_offset_map(pmd,addr) (__pte_map(pmd) + pte_index(addr))
352 #define pte_unmap(pte) __pte_unmap(pte)
353
354 #define pte_pfn(pte) (pte_val(pte) >> PAGE_SHIFT)
355 #define pfn_pte(pfn,prot) __pte(__pfn_to_phys(pfn) | pgprot_val(prot))
356
357 #define pte_page(pte) pfn_to_page(pte_pfn(pte))
358 #define mk_pte(page,prot) pfn_pte(page_to_pfn(page), prot)
359
360 #define set_pte_ext(ptep,pte,ext) cpu_set_pte_ext(ptep,pte,ext)
361 #define pte_clear(mm,addr,ptep) set_pte_ext(ptep, __pte(0), 0)
362
363 #if __LINUX_ARM_ARCH__ < 6
__sync_icache_dcache(pte_t pteval)364 static inline void __sync_icache_dcache(pte_t pteval)
365 {
366 }
367 #else
368 extern void __sync_icache_dcache(pte_t pteval);
369 #endif
370
set_pte_at(struct mm_struct * mm,unsigned long addr,pte_t * ptep,pte_t pteval)371 static inline void set_pte_at(struct mm_struct *mm, unsigned long addr,
372 pte_t *ptep, pte_t pteval)
373 {
374 if (addr >= TASK_SIZE)
375 set_pte_ext(ptep, pteval, 0);
376 else {
377 __sync_icache_dcache(pteval);
378 set_pte_ext(ptep, pteval, PTE_EXT_NG);
379 }
380 }
381
382 #define pte_none(pte) (!pte_val(pte))
383 #define pte_present(pte) (pte_val(pte) & L_PTE_PRESENT)
384 #define pte_write(pte) (!(pte_val(pte) & L_PTE_RDONLY))
385 #define pte_dirty(pte) (pte_val(pte) & L_PTE_DIRTY)
386 #define pte_young(pte) (pte_val(pte) & L_PTE_YOUNG)
387 #define pte_exec(pte) (!(pte_val(pte) & L_PTE_XN))
388 #define pte_special(pte) (0)
389
390 #define pte_present_user(pte) \
391 ((pte_val(pte) & (L_PTE_PRESENT | L_PTE_USER)) == \
392 (L_PTE_PRESENT | L_PTE_USER))
393
394 #define PTE_BIT_FUNC(fn,op) \
395 static inline pte_t pte_##fn(pte_t pte) { pte_val(pte) op; return pte; }
396
397 PTE_BIT_FUNC(wrprotect, |= L_PTE_RDONLY);
398 PTE_BIT_FUNC(mkwrite, &= ~L_PTE_RDONLY);
399 PTE_BIT_FUNC(mkclean, &= ~L_PTE_DIRTY);
400 PTE_BIT_FUNC(mkdirty, |= L_PTE_DIRTY);
401 PTE_BIT_FUNC(mkold, &= ~L_PTE_YOUNG);
402 PTE_BIT_FUNC(mkyoung, |= L_PTE_YOUNG);
403
pte_mkspecial(pte_t pte)404 static inline pte_t pte_mkspecial(pte_t pte) { return pte; }
405
pte_modify(pte_t pte,pgprot_t newprot)406 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
407 {
408 const pteval_t mask = L_PTE_XN | L_PTE_RDONLY | L_PTE_USER;
409 pte_val(pte) = (pte_val(pte) & ~mask) | (pgprot_val(newprot) & mask);
410 return pte;
411 }
412
413 /*
414 * Encode and decode a swap entry. Swap entries are stored in the Linux
415 * page tables as follows:
416 *
417 * 3 3 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1
418 * 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
419 * <--------------- offset --------------------> <- type --> 0 0 0
420 *
421 * This gives us up to 63 swap files and 32GB per swap file. Note that
422 * the offset field is always non-zero.
423 */
424 #define __SWP_TYPE_SHIFT 3
425 #define __SWP_TYPE_BITS 6
426 #define __SWP_TYPE_MASK ((1 << __SWP_TYPE_BITS) - 1)
427 #define __SWP_OFFSET_SHIFT (__SWP_TYPE_BITS + __SWP_TYPE_SHIFT)
428
429 #define __swp_type(x) (((x).val >> __SWP_TYPE_SHIFT) & __SWP_TYPE_MASK)
430 #define __swp_offset(x) ((x).val >> __SWP_OFFSET_SHIFT)
431 #define __swp_entry(type,offset) ((swp_entry_t) { ((type) << __SWP_TYPE_SHIFT) | ((offset) << __SWP_OFFSET_SHIFT) })
432
433 #define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
434 #define __swp_entry_to_pte(swp) ((pte_t) { (swp).val })
435
436 /*
437 * It is an error for the kernel to have more swap files than we can
438 * encode in the PTEs. This ensures that we know when MAX_SWAPFILES
439 * is increased beyond what we presently support.
440 */
441 #define MAX_SWAPFILES_CHECK() BUILD_BUG_ON(MAX_SWAPFILES_SHIFT > __SWP_TYPE_BITS)
442
443 /*
444 * Encode and decode a file entry. File entries are stored in the Linux
445 * page tables as follows:
446 *
447 * 3 3 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1
448 * 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
449 * <----------------------- offset ------------------------> 1 0 0
450 */
451 #define pte_file(pte) (pte_val(pte) & L_PTE_FILE)
452 #define pte_to_pgoff(x) (pte_val(x) >> 3)
453 #define pgoff_to_pte(x) __pte(((x) << 3) | L_PTE_FILE)
454
455 #define PTE_FILE_MAX_BITS 29
456
457 /* Needs to be defined here and not in linux/mm.h, as it is arch dependent */
458 /* FIXME: this is not correct */
459 #define kern_addr_valid(addr) (1)
460
461 #include <asm-generic/pgtable.h>
462
463 /*
464 * We provide our own arch_get_unmapped_area to cope with VIPT caches.
465 */
466 #define HAVE_ARCH_UNMAPPED_AREA
467
468 /*
469 * remap a physical page `pfn' of size `size' with page protection `prot'
470 * into virtual address `from'
471 */
472 #define io_remap_pfn_range(vma,from,pfn,size,prot) \
473 remap_pfn_range(vma, from, pfn, size, prot)
474
475 #define pgtable_cache_init() do { } while (0)
476
477 void identity_mapping_add(pgd_t *, unsigned long, unsigned long);
478 void identity_mapping_del(pgd_t *, unsigned long, unsigned long);
479
480 #endif /* !__ASSEMBLY__ */
481
482 #endif /* CONFIG_MMU */
483
484 #endif /* _ASMARM_PGTABLE_H */
485