2 * CRIS pgtable.h - macros and functions to manipulate page tables.
5 #ifndef _CRIS_PGTABLE_H
6 #define _CRIS_PGTABLE_H
8 #include <linux/config.h>
9 #include <linux/sched.h>
11 #include <asm/arch/pgtable.h>
14 * The Linux memory management assumes a three-level page table setup. On
15 * CRIS, we use that, but "fold" the mid level into the top-level page
16 * table. Since the MMU TLB is software loaded through an interrupt, it
17 * supports any page table structure, so we could have used a three-level
18 * setup, but for the amounts of memory we normally use, a two-level is
19 * probably more efficient.
21 * This file contains the functions and defines necessary to modify and use
22 * the CRIS page table tree.
25 extern void paging_init(void);
27 /* Certain architectures need to do special things when pte's
28 * within a page table are directly modified. Thus, the following
29 * hook is made available.
31 #define set_pte(pteptr, pteval) ((*(pteptr)) = (pteval))
33 * (pmds are folded into pgds so this doesn't get actually called,
34 * but the define is needed for a generic inline function.)
36 #define set_pmd(pmdptr, pmdval) (*(pmdptr) = pmdval)
37 #define set_pgd(pgdptr, pgdval) (*(pgdptr) = pgdval)
39 /* PMD_SHIFT determines the size of the area a second-level page table can
40 * map. It is equal to the page size times the number of PTE's that fit in
41 * a PMD page. A PTE is 4-bytes in CRIS. Hence the following number.
44 #define PMD_SHIFT (PAGE_SHIFT + (PAGE_SHIFT-2))
45 #define PMD_SIZE (1UL << PMD_SHIFT)
46 #define PMD_MASK (~(PMD_SIZE-1))
48 /* PGDIR_SHIFT determines what a third-level page table entry can map.
49 * Since we fold into a two-level structure, this is the same as PMD_SHIFT.
52 #define PGDIR_SHIFT PMD_SHIFT
53 #define PGDIR_SIZE (1UL << PGDIR_SHIFT)
54 #define PGDIR_MASK (~(PGDIR_SIZE-1))
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).
62 #define PTRS_PER_PTE (1UL << (PAGE_SHIFT-2))
63 #define PTRS_PER_PMD 1
64 #define PTRS_PER_PGD (1UL << (PAGE_SHIFT-2))
66 /* calculate how many PGD entries a user-level program can use
67 * the first mappable virtual address is 0
68 * (TASK_SIZE is the maximum virtual address space)
71 #define USER_PTRS_PER_PGD (TASK_SIZE/PGDIR_SIZE)
72 #define FIRST_USER_PGD_NR 0
74 /* zero page used for uninitialized stuff */
75 extern unsigned long empty_zero_page;
76 #define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
78 /* number of bits that fit into a memory pointer */
79 #define BITS_PER_PTR (8*sizeof(unsigned long))
81 /* to align the pointer to a pointer address */
82 #define PTR_MASK (~(sizeof(void*)-1))
84 /* sizeof(void*)==1<<SIZEOF_PTR_LOG2 */
85 /* 64-bit machines, beware! SRB. */
86 #define SIZEOF_PTR_LOG2 2
88 /* to find an entry in a page-table */
89 #define PAGE_PTR(address) \
90 ((unsigned long)(address)>>(PAGE_SHIFT-SIZEOF_PTR_LOG2)&PTR_MASK&~PAGE_MASK)
92 /* to set the page-dir */
93 #define SET_PAGE_DIR(tsk,pgdir)
95 #define pte_none(x) (!pte_val(x))
96 #define pte_present(x) (pte_val(x) & _PAGE_PRESENT)
97 #define pte_clear(xp) do { pte_val(*(xp)) = 0; } while (0)
99 #define pmd_none(x) (!pmd_val(x))
100 /* by removing the _PAGE_KERNEL bit from the comparision, the same pmd_bad
101 * works for both _PAGE_TABLE and _KERNPG_TABLE pmd entries.
103 #define pmd_bad(x) ((pmd_val(x) & (~PAGE_MASK & ~_PAGE_KERNEL)) != _PAGE_TABLE)
104 #define pmd_present(x) (pmd_val(x) & _PAGE_PRESENT)
105 #define pmd_clear(xp) do { pmd_val(*(xp)) = 0; } while (0)
108 * The "pgd_xxx()" functions here are trivial for a folded two-level
109 * setup: the pgd is never bad, and a pmd always exists (as it's folded
110 * into the pgd entry)
112 extern inline int pgd_none(pgd_t pgd) { return 0; }
113 extern inline int pgd_bad(pgd_t pgd) { return 0; }
114 extern inline int pgd_present(pgd_t pgd) { return 1; }
115 extern inline void pgd_clear(pgd_t * pgdp) { }
118 * The following only work if pte_present() is true.
119 * Undefined behaviour if not..
122 extern inline int pte_read(pte_t pte) { return pte_val(pte) & _PAGE_READ; }
123 extern inline int pte_write(pte_t pte) { return pte_val(pte) & _PAGE_WRITE; }
124 extern inline int pte_exec(pte_t pte) { return pte_val(pte) & _PAGE_READ; }
125 extern inline int pte_dirty(pte_t pte) { return pte_val(pte) & _PAGE_MODIFIED; }
126 extern inline int pte_young(pte_t pte) { return pte_val(pte) & _PAGE_ACCESSED; }
127 extern inline int pte_file(pte_t pte) { return pte_val(pte) & _PAGE_FILE; }
129 extern inline pte_t pte_wrprotect(pte_t pte)
131 pte_val(pte) &= ~(_PAGE_WRITE | _PAGE_SILENT_WRITE);
135 extern inline pte_t pte_rdprotect(pte_t pte)
137 pte_val(pte) &= ~(_PAGE_READ | _PAGE_SILENT_READ);
141 extern inline pte_t pte_exprotect(pte_t pte)
143 pte_val(pte) &= ~(_PAGE_READ | _PAGE_SILENT_READ);
147 extern inline pte_t pte_mkclean(pte_t pte)
149 pte_val(pte) &= ~(_PAGE_MODIFIED | _PAGE_SILENT_WRITE);
153 extern inline pte_t pte_mkold(pte_t pte)
155 pte_val(pte) &= ~(_PAGE_ACCESSED | _PAGE_SILENT_READ);
159 extern inline pte_t pte_mkwrite(pte_t pte)
161 pte_val(pte) |= _PAGE_WRITE;
162 if (pte_val(pte) & _PAGE_MODIFIED)
163 pte_val(pte) |= _PAGE_SILENT_WRITE;
167 extern inline pte_t pte_mkread(pte_t pte)
169 pte_val(pte) |= _PAGE_READ;
170 if (pte_val(pte) & _PAGE_ACCESSED)
171 pte_val(pte) |= _PAGE_SILENT_READ;
175 extern inline pte_t pte_mkexec(pte_t pte)
177 pte_val(pte) |= _PAGE_READ;
178 if (pte_val(pte) & _PAGE_ACCESSED)
179 pte_val(pte) |= _PAGE_SILENT_READ;
183 extern inline pte_t pte_mkdirty(pte_t pte)
185 pte_val(pte) |= _PAGE_MODIFIED;
186 if (pte_val(pte) & _PAGE_WRITE)
187 pte_val(pte) |= _PAGE_SILENT_WRITE;
191 extern inline pte_t pte_mkyoung(pte_t pte)
193 pte_val(pte) |= _PAGE_ACCESSED;
194 if (pte_val(pte) & _PAGE_READ)
196 pte_val(pte) |= _PAGE_SILENT_READ;
197 if ((pte_val(pte) & (_PAGE_WRITE | _PAGE_MODIFIED)) ==
198 (_PAGE_WRITE | _PAGE_MODIFIED))
199 pte_val(pte) |= _PAGE_SILENT_WRITE;
205 * Conversion functions: convert a page and protection to a page entry,
206 * and a page entry and page directory to the page they refer to.
209 /* What actually goes as arguments to the various functions is less than
210 * obvious, but a rule of thumb is that struct page's goes as struct page *,
211 * really physical DRAM addresses are unsigned long's, and DRAM "virtual"
212 * addresses (the 0xc0xxxxxx's) goes as void *'s.
215 extern inline pte_t __mk_pte(void * page, pgprot_t pgprot)
218 /* the PTE needs a physical address */
219 pte_val(pte) = __pa(page) | pgprot_val(pgprot);
223 #define mk_pte(page, pgprot) __mk_pte(page_address(page), (pgprot))
225 #define mk_pte_phys(physpage, pgprot) \
229 pte_val(__pte) = (physpage) + pgprot_val(pgprot); \
233 extern inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
234 { pte_val(pte) = (pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot); return pte; }
237 /* pte_val refers to a page in the 0x4xxxxxxx physical DRAM interval
238 * __pte_page(pte_val) refers to the "virtual" DRAM interval
239 * pte_pagenr refers to the page-number counted starting from the virtual DRAM start
242 extern inline unsigned long __pte_page(pte_t pte)
244 /* the PTE contains a physical address */
245 return (unsigned long)__va(pte_val(pte) & PAGE_MASK);
248 #define pte_pagenr(pte) ((__pte_page(pte) - PAGE_OFFSET) >> PAGE_SHIFT)
250 /* permanent address of a page */
252 #define __page_address(page) (PAGE_OFFSET + (((page) - mem_map) << PAGE_SHIFT))
253 #define pte_page(pte) (mem_map+pte_pagenr(pte))
255 /* only the pte's themselves need to point to physical DRAM (see above)
256 * the pagetable links are purely handled within the kernel SW and thus
257 * don't need the __pa and __va transformations.
260 extern inline void pmd_set(pmd_t * pmdp, pte_t * ptep)
261 { pmd_val(*pmdp) = _PAGE_TABLE | (unsigned long) ptep; }
263 #define pmd_page(pmd) (pfn_to_page(pmd_val(pmd) >> PAGE_SHIFT))
264 #define pmd_page_kernel(pmd) ((unsigned long) __va(pmd_val(pmd) & PAGE_MASK))
266 /* to find an entry in a page-table-directory. */
267 #define pgd_index(address) ((address >> PGDIR_SHIFT) & (PTRS_PER_PGD-1))
269 /* to find an entry in a page-table-directory */
270 extern inline pgd_t * pgd_offset(struct mm_struct * mm, unsigned long address)
272 return mm->pgd + pgd_index(address);
275 /* to find an entry in a kernel page-table-directory */
276 #define pgd_offset_k(address) pgd_offset(&init_mm, address)
278 /* Find an entry in the second-level page table.. */
279 extern inline pmd_t * pmd_offset(pgd_t * dir, unsigned long address)
281 return (pmd_t *) dir;
284 /* Find an entry in the third-level page table.. */
285 #define __pte_offset(address) \
286 (((address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
287 #define pte_offset_kernel(dir, address) \
288 ((pte_t *) pmd_page_kernel(*(dir)) + __pte_offset(address))
289 #define pte_offset_map(dir, address) \
290 ((pte_t *)page_address(pmd_page(*(dir))) + __pte_offset(address))
291 #define pte_offset_map_nested(dir, address) pte_offset_map(dir, address)
293 #define pte_unmap(pte) do { } while (0)
294 #define pte_unmap_nested(pte) do { } while (0)
295 #define pte_pfn(x) ((unsigned long)(__va((x).pte)) >> PAGE_SHIFT)
296 #define pfn_pte(pfn, prot) __pte((__pa((pfn) << PAGE_SHIFT)) | pgprot_val(prot))
298 #define pte_ERROR(e) \
299 printk("%s:%d: bad pte %p(%08lx).\n", __FILE__, __LINE__, &(e), pte_val(e))
300 #define pmd_ERROR(e) \
301 printk("%s:%d: bad pmd %p(%08lx).\n", __FILE__, __LINE__, &(e), pmd_val(e))
302 #define pgd_ERROR(e) \
303 printk("%s:%d: bad pgd %p(%08lx).\n", __FILE__, __LINE__, &(e), pgd_val(e))
306 extern pgd_t swapper_pg_dir[PTRS_PER_PGD]; /* defined in head.S */
309 * CRIS doesn't have any external MMU info: the kernel page
310 * tables contain all the necessary information.
312 * Actually I am not sure on what this could be used for.
314 extern inline void update_mmu_cache(struct vm_area_struct * vma,
315 unsigned long address, pte_t pte)
319 /* Encode and de-code a swap entry (must be !pte_none(e) && !pte_present(e)) */
320 /* Since the PAGE_PRESENT bit is bit 4, we can use the bits above */
322 #define __swp_type(x) (((x).val >> 5) & 0x7f)
323 #define __swp_offset(x) ((x).val >> 12)
324 #define __swp_entry(type, offset) ((swp_entry_t) { ((type) << 5) | ((offset) << 12) })
325 #define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
326 #define __swp_entry_to_pte(x) ((pte_t) { (x).val })
328 #define kern_addr_valid(addr) (1)
330 #include <asm-generic/pgtable.h>
333 * No page table caches to initialise
335 #define pgtable_cache_init() do { } while (0)
337 #define pte_to_pgoff(x) (pte_val(x) >> 6)
338 #define pgoff_to_pte(x) __pte(((x) << 6) | _PAGE_FILE)
340 typedef pte_t *pte_addr_t;
342 #endif /* _CRIS_PGTABLE_H */