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Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
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linux
1/*
2 * CRIS pgtable.h - macros and functions to manipulate page tables.
3 */
4
5#ifndef _CRIS_PGTABLE_H
6#define _CRIS_PGTABLE_H
7
8#include <asm-generic/4level-fixup.h>
9
10#ifndef __ASSEMBLY__
11#include <linux/config.h>
12#include <linux/sched.h>
13#include <asm/mmu.h>
14#endif
15#include <asm/arch/pgtable.h>
16
17/*
18 * The Linux memory management assumes a three-level page table setup. On
19 * CRIS, we use that, but "fold" the mid level into the top-level page
20 * table. Since the MMU TLB is software loaded through an interrupt, it
21 * supports any page table structure, so we could have used a three-level
22 * setup, but for the amounts of memory we normally use, a two-level is
23 * probably more efficient.
24 *
25 * This file contains the functions and defines necessary to modify and use
26 * the CRIS page table tree.
27 */
28#ifndef __ASSEMBLY__
29extern void paging_init(void);
30#endif
31
32/* Certain architectures need to do special things when pte's
33 * within a page table are directly modified. Thus, the following
34 * hook is made available.
35 */
36#define set_pte(pteptr, pteval) ((*(pteptr)) = (pteval))
37#define set_pte_at(mm,addr,ptep,pteval) set_pte(ptep,pteval)
38
39/*
40 * (pmds are folded into pgds so this doesn't get actually called,
41 * but the define is needed for a generic inline function.)
42 */
43#define set_pmd(pmdptr, pmdval) (*(pmdptr) = pmdval)
44#define set_pgd(pgdptr, pgdval) (*(pgdptr) = pgdval)
45
46/* PMD_SHIFT determines the size of the area a second-level page table can
47 * map. It is equal to the page size times the number of PTE's that fit in
48 * a PMD page. A PTE is 4-bytes in CRIS. Hence the following number.
49 */
50
51#define PMD_SHIFT (PAGE_SHIFT + (PAGE_SHIFT-2))
52#define PMD_SIZE (1UL << PMD_SHIFT)
53#define PMD_MASK (~(PMD_SIZE-1))
54
55/* PGDIR_SHIFT determines what a third-level page table entry can map.
56 * Since we fold into a two-level structure, this is the same as PMD_SHIFT.
57 */
58
59#define PGDIR_SHIFT PMD_SHIFT
60#define PGDIR_SIZE (1UL << PGDIR_SHIFT)
61#define PGDIR_MASK (~(PGDIR_SIZE-1))
62
63/*
64 * entries per page directory level: we use a two-level, so
65 * we don't really have any PMD directory physically.
66 * pointers are 4 bytes so we can use the page size and
67 * divide it by 4 (shift by 2).
68 */
69#define PTRS_PER_PTE (1UL << (PAGE_SHIFT-2))
70#define PTRS_PER_PMD 1
71#define PTRS_PER_PGD (1UL << (PAGE_SHIFT-2))
72
73/* calculate how many PGD entries a user-level program can use
74 * the first mappable virtual address is 0
75 * (TASK_SIZE is the maximum virtual address space)
76 */
77
78#define USER_PTRS_PER_PGD (TASK_SIZE/PGDIR_SIZE)
79#define FIRST_USER_PGD_NR 0
80
81/* zero page used for uninitialized stuff */
82#ifndef __ASSEMBLY__
83extern unsigned long empty_zero_page;
84#define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
85#endif
86
87/* number of bits that fit into a memory pointer */
88#define BITS_PER_PTR (8*sizeof(unsigned long))
89
90/* to align the pointer to a pointer address */
91#define PTR_MASK (~(sizeof(void*)-1))
92
93/* sizeof(void*)==1<<SIZEOF_PTR_LOG2 */
94/* 64-bit machines, beware! SRB. */
95#define SIZEOF_PTR_LOG2 2
96
97/* to find an entry in a page-table */
98#define PAGE_PTR(address) \
99((unsigned long)(address)>>(PAGE_SHIFT-SIZEOF_PTR_LOG2)&PTR_MASK&~PAGE_MASK)
100
101/* to set the page-dir */
102#define SET_PAGE_DIR(tsk,pgdir)
103
104#define pte_none(x) (!pte_val(x))
105#define pte_present(x) (pte_val(x) & _PAGE_PRESENT)
106#define pte_clear(mm,addr,xp) do { pte_val(*(xp)) = 0; } while (0)
107
108#define pmd_none(x) (!pmd_val(x))
109/* by removing the _PAGE_KERNEL bit from the comparision, the same pmd_bad
110 * works for both _PAGE_TABLE and _KERNPG_TABLE pmd entries.
111 */
112#define pmd_bad(x) ((pmd_val(x) & (~PAGE_MASK & ~_PAGE_KERNEL)) != _PAGE_TABLE)
113#define pmd_present(x) (pmd_val(x) & _PAGE_PRESENT)
114#define pmd_clear(xp) do { pmd_val(*(xp)) = 0; } while (0)
115
116#ifndef __ASSEMBLY__
117
118/*
119 * The "pgd_xxx()" functions here are trivial for a folded two-level
120 * setup: the pgd is never bad, and a pmd always exists (as it's folded
121 * into the pgd entry)
122 */
123extern inline int pgd_none(pgd_t pgd) { return 0; }
124extern inline int pgd_bad(pgd_t pgd) { return 0; }
125extern inline int pgd_present(pgd_t pgd) { return 1; }
126extern inline void pgd_clear(pgd_t * pgdp) { }
127
128/*
129 * The following only work if pte_present() is true.
130 * Undefined behaviour if not..
131 */
132
133extern inline int pte_read(pte_t pte) { return pte_val(pte) & _PAGE_READ; }
134extern inline int pte_write(pte_t pte) { return pte_val(pte) & _PAGE_WRITE; }
135extern inline int pte_exec(pte_t pte) { return pte_val(pte) & _PAGE_READ; }
136extern inline int pte_dirty(pte_t pte) { return pte_val(pte) & _PAGE_MODIFIED; }
137extern inline int pte_young(pte_t pte) { return pte_val(pte) & _PAGE_ACCESSED; }
138extern inline int pte_file(pte_t pte) { return pte_val(pte) & _PAGE_FILE; }
139
140extern inline pte_t pte_wrprotect(pte_t pte)
141{
142 pte_val(pte) &= ~(_PAGE_WRITE | _PAGE_SILENT_WRITE);
143 return pte;
144}
145
146extern inline pte_t pte_rdprotect(pte_t pte)
147{
148 pte_val(pte) &= ~(_PAGE_READ | _PAGE_SILENT_READ);
149 return pte;
150}
151
152extern inline pte_t pte_exprotect(pte_t pte)
153{
154 pte_val(pte) &= ~(_PAGE_READ | _PAGE_SILENT_READ);
155 return pte;
156}
157
158extern inline pte_t pte_mkclean(pte_t pte)
159{
160 pte_val(pte) &= ~(_PAGE_MODIFIED | _PAGE_SILENT_WRITE);
161 return pte;
162}
163
164extern inline pte_t pte_mkold(pte_t pte)
165{
166 pte_val(pte) &= ~(_PAGE_ACCESSED | _PAGE_SILENT_READ);
167 return pte;
168}
169
170extern inline pte_t pte_mkwrite(pte_t pte)
171{
172 pte_val(pte) |= _PAGE_WRITE;
173 if (pte_val(pte) & _PAGE_MODIFIED)
174 pte_val(pte) |= _PAGE_SILENT_WRITE;
175 return pte;
176}
177
178extern inline pte_t pte_mkread(pte_t pte)
179{
180 pte_val(pte) |= _PAGE_READ;
181 if (pte_val(pte) & _PAGE_ACCESSED)
182 pte_val(pte) |= _PAGE_SILENT_READ;
183 return pte;
184}
185
186extern inline pte_t pte_mkexec(pte_t pte)
187{
188 pte_val(pte) |= _PAGE_READ;
189 if (pte_val(pte) & _PAGE_ACCESSED)
190 pte_val(pte) |= _PAGE_SILENT_READ;
191 return pte;
192}
193
194extern inline pte_t pte_mkdirty(pte_t pte)
195{
196 pte_val(pte) |= _PAGE_MODIFIED;
197 if (pte_val(pte) & _PAGE_WRITE)
198 pte_val(pte) |= _PAGE_SILENT_WRITE;
199 return pte;
200}
201
202extern inline pte_t pte_mkyoung(pte_t pte)
203{
204 pte_val(pte) |= _PAGE_ACCESSED;
205 if (pte_val(pte) & _PAGE_READ)
206 {
207 pte_val(pte) |= _PAGE_SILENT_READ;
208 if ((pte_val(pte) & (_PAGE_WRITE | _PAGE_MODIFIED)) ==
209 (_PAGE_WRITE | _PAGE_MODIFIED))
210 pte_val(pte) |= _PAGE_SILENT_WRITE;
211 }
212 return pte;
213}
214
215/*
216 * Conversion functions: convert a page and protection to a page entry,
217 * and a page entry and page directory to the page they refer to.
218 */
219
220/* What actually goes as arguments to the various functions is less than
221 * obvious, but a rule of thumb is that struct page's goes as struct page *,
222 * really physical DRAM addresses are unsigned long's, and DRAM "virtual"
223 * addresses (the 0xc0xxxxxx's) goes as void *'s.
224 */
225
226extern inline pte_t __mk_pte(void * page, pgprot_t pgprot)
227{
228 pte_t pte;
229 /* the PTE needs a physical address */
230 pte_val(pte) = __pa(page) | pgprot_val(pgprot);
231 return pte;
232}
233
234#define mk_pte(page, pgprot) __mk_pte(page_address(page), (pgprot))
235
236#define mk_pte_phys(physpage, pgprot) \
237({ \
238 pte_t __pte; \
239 \
240 pte_val(__pte) = (physpage) + pgprot_val(pgprot); \
241 __pte; \
242})
243
244extern inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
245{ pte_val(pte) = (pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot); return pte; }
246
247
248/* pte_val refers to a page in the 0x4xxxxxxx physical DRAM interval
249 * __pte_page(pte_val) refers to the "virtual" DRAM interval
250 * pte_pagenr refers to the page-number counted starting from the virtual DRAM start
251 */
252
253extern inline unsigned long __pte_page(pte_t pte)
254{
255 /* the PTE contains a physical address */
256 return (unsigned long)__va(pte_val(pte) & PAGE_MASK);
257}
258
259#define pte_pagenr(pte) ((__pte_page(pte) - PAGE_OFFSET) >> PAGE_SHIFT)
260
261/* permanent address of a page */
262
263#define __page_address(page) (PAGE_OFFSET + (((page) - mem_map) << PAGE_SHIFT))
264#define pte_page(pte) (mem_map+pte_pagenr(pte))
265
266/* only the pte's themselves need to point to physical DRAM (see above)
267 * the pagetable links are purely handled within the kernel SW and thus
268 * don't need the __pa and __va transformations.
269 */
270
271extern inline void pmd_set(pmd_t * pmdp, pte_t * ptep)
272{ pmd_val(*pmdp) = _PAGE_TABLE | (unsigned long) ptep; }
273
274#define pmd_page(pmd) (pfn_to_page(pmd_val(pmd) >> PAGE_SHIFT))
275#define pmd_page_kernel(pmd) ((unsigned long) __va(pmd_val(pmd) & PAGE_MASK))
276
277/* to find an entry in a page-table-directory. */
278#define pgd_index(address) ((address >> PGDIR_SHIFT) & (PTRS_PER_PGD-1))
279
280/* to find an entry in a page-table-directory */
281extern inline pgd_t * pgd_offset(struct mm_struct * mm, unsigned long address)
282{
283 return mm->pgd + pgd_index(address);
284}
285
286/* to find an entry in a kernel page-table-directory */
287#define pgd_offset_k(address) pgd_offset(&init_mm, address)
288
289/* Find an entry in the second-level page table.. */
290extern inline pmd_t * pmd_offset(pgd_t * dir, unsigned long address)
291{
292 return (pmd_t *) dir;
293}
294
295/* Find an entry in the third-level page table.. */
296#define __pte_offset(address) \
297 (((address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
298#define pte_offset_kernel(dir, address) \
299 ((pte_t *) pmd_page_kernel(*(dir)) + __pte_offset(address))
300#define pte_offset_map(dir, address) \
301 ((pte_t *)page_address(pmd_page(*(dir))) + __pte_offset(address))
302#define pte_offset_map_nested(dir, address) pte_offset_map(dir, address)
303
304#define pte_unmap(pte) do { } while (0)
305#define pte_unmap_nested(pte) do { } while (0)
306#define pte_pfn(x) ((unsigned long)(__va((x).pte)) >> PAGE_SHIFT)
307#define pfn_pte(pfn, prot) __pte((__pa((pfn) << PAGE_SHIFT)) | pgprot_val(prot))
308
309#define pte_ERROR(e) \
310 printk("%s:%d: bad pte %p(%08lx).\n", __FILE__, __LINE__, &(e), pte_val(e))
311#define pmd_ERROR(e) \
312 printk("%s:%d: bad pmd %p(%08lx).\n", __FILE__, __LINE__, &(e), pmd_val(e))
313#define pgd_ERROR(e) \
314 printk("%s:%d: bad pgd %p(%08lx).\n", __FILE__, __LINE__, &(e), pgd_val(e))
315
316
317extern pgd_t swapper_pg_dir[PTRS_PER_PGD]; /* defined in head.S */
318
319/*
320 * CRIS doesn't have any external MMU info: the kernel page
321 * tables contain all the necessary information.
322 *
323 * Actually I am not sure on what this could be used for.
324 */
325extern inline void update_mmu_cache(struct vm_area_struct * vma,
326 unsigned long address, pte_t pte)
327{
328}
329
330/* Encode and de-code a swap entry (must be !pte_none(e) && !pte_present(e)) */
331/* Since the PAGE_PRESENT bit is bit 4, we can use the bits above */
332
333#define __swp_type(x) (((x).val >> 5) & 0x7f)
334#define __swp_offset(x) ((x).val >> 12)
335#define __swp_entry(type, offset) ((swp_entry_t) { ((type) << 5) | ((offset) << 12) })
336#define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
337#define __swp_entry_to_pte(x) ((pte_t) { (x).val })
338
339#define kern_addr_valid(addr) (1)
340
341#include <asm-generic/pgtable.h>
342
343/*
344 * No page table caches to initialise
345 */
346#define pgtable_cache_init() do { } while (0)
347
348#define pte_to_pgoff(x) (pte_val(x) >> 6)
349#define pgoff_to_pte(x) __pte(((x) << 6) | _PAGE_FILE)
350
351#endif /* __ASSEMBLY__ */
352#endif /* _CRIS_PGTABLE_H */