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