File: /usr/src/linux/include/asm-alpha/pgtable.h
1 #ifndef _ALPHA_PGTABLE_H
2 #define _ALPHA_PGTABLE_H
3
4 /*
5 * This file contains the functions and defines necessary to modify and use
6 * the Alpha page table tree.
7 *
8 * This hopefully works with any standard Alpha page-size, as defined
9 * in <asm/page.h> (currently 8192).
10 */
11 #include <linux/config.h>
12 #include <linux/mmzone.h>
13
14 #include <asm/page.h>
15 #include <asm/processor.h> /* For TASK_SIZE */
16 #include <asm/machvec.h>
17
18 /* Certain architectures need to do special things when PTEs
19 * within a page table are directly modified. Thus, the following
20 * hook is made available.
21 */
22 #define set_pte(pteptr, pteval) ((*(pteptr)) = (pteval))
23
24 /* PMD_SHIFT determines the size of the area a second-level page table can map */
25 #define PMD_SHIFT (PAGE_SHIFT + (PAGE_SHIFT-3))
26 #define PMD_SIZE (1UL << PMD_SHIFT)
27 #define PMD_MASK (~(PMD_SIZE-1))
28
29 /* PGDIR_SHIFT determines what a third-level page table entry can map */
30 #define PGDIR_SHIFT (PAGE_SHIFT + 2*(PAGE_SHIFT-3))
31 #define PGDIR_SIZE (1UL << PGDIR_SHIFT)
32 #define PGDIR_MASK (~(PGDIR_SIZE-1))
33
34 /*
35 * Entries per page directory level: the Alpha is three-level, with
36 * all levels having a one-page page table.
37 */
38 #define PTRS_PER_PTE (1UL << (PAGE_SHIFT-3))
39 #define PTRS_PER_PMD (1UL << (PAGE_SHIFT-3))
40 #define PTRS_PER_PGD (1UL << (PAGE_SHIFT-3))
41 #define USER_PTRS_PER_PGD (TASK_SIZE / PGDIR_SIZE)
42 #define FIRST_USER_PGD_NR 0
43
44 /* Number of pointers that fit on a page: this will go away. */
45 #define PTRS_PER_PAGE (1UL << (PAGE_SHIFT-3))
46
47 #ifdef CONFIG_ALPHA_LARGE_VMALLOC
48 #define VMALLOC_START 0xfffffe0000000000
49 #else
50 #define VMALLOC_START (-2*PGDIR_SIZE)
51 #endif
52 #define VMALLOC_VMADDR(x) ((unsigned long)(x))
53 #define VMALLOC_END (-PGDIR_SIZE)
54
55 /*
56 * OSF/1 PAL-code-imposed page table bits
57 */
58 #define _PAGE_VALID 0x0001
59 #define _PAGE_FOR 0x0002 /* used for page protection (fault on read) */
60 #define _PAGE_FOW 0x0004 /* used for page protection (fault on write) */
61 #define _PAGE_FOE 0x0008 /* used for page protection (fault on exec) */
62 #define _PAGE_ASM 0x0010
63 #define _PAGE_KRE 0x0100 /* xxx - see below on the "accessed" bit */
64 #define _PAGE_URE 0x0200 /* xxx */
65 #define _PAGE_KWE 0x1000 /* used to do the dirty bit in software */
66 #define _PAGE_UWE 0x2000 /* used to do the dirty bit in software */
67
68 /* .. and these are ours ... */
69 #define _PAGE_DIRTY 0x20000
70 #define _PAGE_ACCESSED 0x40000
71
72 /*
73 * NOTE! The "accessed" bit isn't necessarily exact: it can be kept exactly
74 * by software (use the KRE/URE/KWE/UWE bits appropriately), but I'll fake it.
75 * Under Linux/AXP, the "accessed" bit just means "read", and I'll just use
76 * the KRE/URE bits to watch for it. That way we don't need to overload the
77 * KWE/UWE bits with both handling dirty and accessed.
78 *
79 * Note that the kernel uses the accessed bit just to check whether to page
80 * out a page or not, so it doesn't have to be exact anyway.
81 */
82
83 #define __DIRTY_BITS (_PAGE_DIRTY | _PAGE_KWE | _PAGE_UWE)
84 #define __ACCESS_BITS (_PAGE_ACCESSED | _PAGE_KRE | _PAGE_URE)
85
86 #define _PFN_MASK 0xFFFFFFFF00000000
87
88 #define _PAGE_TABLE (_PAGE_VALID | __DIRTY_BITS | __ACCESS_BITS)
89 #define _PAGE_CHG_MASK (_PFN_MASK | __DIRTY_BITS | __ACCESS_BITS)
90
91 /*
92 * All the normal masks have the "page accessed" bits on, as any time they are used,
93 * the page is accessed. They are cleared only by the page-out routines
94 */
95 #define PAGE_NONE __pgprot(_PAGE_VALID | __ACCESS_BITS | _PAGE_FOR | _PAGE_FOW | _PAGE_FOE)
96 #define PAGE_SHARED __pgprot(_PAGE_VALID | __ACCESS_BITS)
97 #define PAGE_COPY __pgprot(_PAGE_VALID | __ACCESS_BITS | _PAGE_FOW)
98 #define PAGE_READONLY __pgprot(_PAGE_VALID | __ACCESS_BITS | _PAGE_FOW)
99 #define PAGE_KERNEL __pgprot(_PAGE_VALID | _PAGE_ASM | _PAGE_KRE | _PAGE_KWE)
100
101 #define _PAGE_NORMAL(x) __pgprot(_PAGE_VALID | __ACCESS_BITS | (x))
102
103 #define _PAGE_P(x) _PAGE_NORMAL((x) | (((x) & _PAGE_FOW)?0:_PAGE_FOW))
104 #define _PAGE_S(x) _PAGE_NORMAL(x)
105
106 /*
107 * The hardware can handle write-only mappings, but as the Alpha
108 * architecture does byte-wide writes with a read-modify-write
109 * sequence, it's not practical to have write-without-read privs.
110 * Thus the "-w- -> rw-" and "-wx -> rwx" mapping here (and in
111 * arch/alpha/mm/fault.c)
112 */
113 /* xwr */
114 #define __P000 _PAGE_P(_PAGE_FOE | _PAGE_FOW | _PAGE_FOR)
115 #define __P001 _PAGE_P(_PAGE_FOE | _PAGE_FOW)
116 #define __P010 _PAGE_P(_PAGE_FOE)
117 #define __P011 _PAGE_P(_PAGE_FOE)
118 #define __P100 _PAGE_P(_PAGE_FOW | _PAGE_FOR)
119 #define __P101 _PAGE_P(_PAGE_FOW)
120 #define __P110 _PAGE_P(0)
121 #define __P111 _PAGE_P(0)
122
123 #define __S000 _PAGE_S(_PAGE_FOE | _PAGE_FOW | _PAGE_FOR)
124 #define __S001 _PAGE_S(_PAGE_FOE | _PAGE_FOW)
125 #define __S010 _PAGE_S(_PAGE_FOE)
126 #define __S011 _PAGE_S(_PAGE_FOE)
127 #define __S100 _PAGE_S(_PAGE_FOW | _PAGE_FOR)
128 #define __S101 _PAGE_S(_PAGE_FOW)
129 #define __S110 _PAGE_S(0)
130 #define __S111 _PAGE_S(0)
131
132 /*
133 * BAD_PAGETABLE is used when we need a bogus page-table, while
134 * BAD_PAGE is used for a bogus page.
135 *
136 * ZERO_PAGE is a global shared page that is always zero: used
137 * for zero-mapped memory areas etc..
138 */
139 extern pte_t __bad_page(void);
140 extern pmd_t * __bad_pagetable(void);
141
142 extern unsigned long __zero_page(void);
143
144 #define BAD_PAGETABLE __bad_pagetable()
145 #define BAD_PAGE __bad_page()
146 #define ZERO_PAGE(vaddr) (virt_to_page(ZERO_PGE))
147
148 /* number of bits that fit into a memory pointer */
149 #define BITS_PER_PTR (8*sizeof(unsigned long))
150
151 /* to align the pointer to a pointer address */
152 #define PTR_MASK (~(sizeof(void*)-1))
153
154 /* sizeof(void*)==1<<SIZEOF_PTR_LOG2 */
155 #define SIZEOF_PTR_LOG2 3
156
157 /* to find an entry in a page-table */
158 #define PAGE_PTR(address) \
159 ((unsigned long)(address)>>(PAGE_SHIFT-SIZEOF_PTR_LOG2)&PTR_MASK&~PAGE_MASK)
160
161 /*
162 * On certain platforms whose physical address space can overlap KSEG,
163 * namely EV6 and above, we must re-twiddle the physaddr to restore the
164 * correct high-order bits.
165 *
166 * This is extremely confusing until you realize that this is actually
167 * just working around a userspace bug. The X server was intending to
168 * provide the physical address but instead provided the KSEG address.
169 * Or tried to, except it's not representable.
170 *
171 * On Tsunami there's nothing meaningful at 0x40000000000, so this is
172 * a safe thing to do. Come the first core logic that does put something
173 * in this area -- memory or whathaveyou -- then this hack will have
174 * to go away. So be prepared!
175 */
176
177 #if defined(CONFIG_ALPHA_GENERIC) && defined(USE_48_BIT_KSEG)
178 #error "EV6-only feature in a generic kernel"
179 #endif
180 #if defined(CONFIG_ALPHA_GENERIC) || \
181 ((defined(CONFIG_ALPHA_EV6) || defined(CONFIG_ALPHA_EV67)) && \
182 !defined(USE_48_BIT_KSEG))
183 #define PHYS_TWIDDLE(phys) \
184 ((((phys) & 0xc0000000000UL) == 0x40000000000UL) \
185 ? ((phys) ^= 0xc0000000000UL) : (phys))
186 #else
187 #define PHYS_TWIDDLE(phys) (phys)
188 #endif
189
190 /*
191 * Conversion functions: convert a page and protection to a page entry,
192 * and a page entry and page directory to the page they refer to.
193 */
194 #ifndef CONFIG_DISCONTIGMEM
195 #define PAGE_TO_PA(page) ((page - mem_map) << PAGE_SHIFT)
196 #else
197 #define PAGE_TO_PA(page) \
198 ((((page)-(page)->zone->zone_mem_map) << PAGE_SHIFT) \
199 + (page)->zone->zone_start_paddr)
200 #endif
201
202 #ifndef CONFIG_DISCONTIGMEM
203 #define mk_pte(page, pgprot) \
204 ({ \
205 pte_t pte; \
206 \
207 pte_val(pte) = ((unsigned long)(page - mem_map) << 32) | \
208 pgprot_val(pgprot); \
209 pte; \
210 })
211 #else
212 #define mk_pte(page, pgprot) \
213 ({ \
214 pte_t pte; \
215 unsigned long pfn; \
216 \
217 pfn = ((unsigned long)((page)-(page)->zone->zone_mem_map)) << 32; \
218 pfn += (page)->zone->zone_start_paddr << (32-PAGE_SHIFT); \
219 pte_val(pte) = pfn | pgprot_val(pgprot); \
220 \
221 pte; \
222 })
223 #endif
224
225 extern inline pte_t mk_pte_phys(unsigned long physpage, pgprot_t pgprot)
226 { pte_t pte; pte_val(pte) = (PHYS_TWIDDLE(physpage) << (32-PAGE_SHIFT)) | pgprot_val(pgprot); return pte; }
227
228 extern inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
229 { pte_val(pte) = (pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot); return pte; }
230
231 extern inline void pmd_set(pmd_t * pmdp, pte_t * ptep)
232 { pmd_val(*pmdp) = _PAGE_TABLE | ((((unsigned long) ptep) - PAGE_OFFSET) << (32-PAGE_SHIFT)); }
233
234 extern inline void pgd_set(pgd_t * pgdp, pmd_t * pmdp)
235 { pgd_val(*pgdp) = _PAGE_TABLE | ((((unsigned long) pmdp) - PAGE_OFFSET) << (32-PAGE_SHIFT)); }
236
237 #ifndef CONFIG_DISCONTIGMEM
238 #define pte_page(x) (mem_map+(unsigned long)((pte_val(x) >> 32)))
239 #else
240 #define pte_page(x) \
241 ({ \
242 unsigned long kvirt; \
243 struct page * __xx; \
244 \
245 kvirt = (unsigned long)__va(pte_val(x) >> (32-PAGE_SHIFT)); \
246 __xx = virt_to_page(kvirt); \
247 \
248 __xx; \
249 })
250 #endif
251
252 extern inline unsigned long pmd_page(pmd_t pmd)
253 { return PAGE_OFFSET + ((pmd_val(pmd) & _PFN_MASK) >> (32-PAGE_SHIFT)); }
254
255 extern inline unsigned long pgd_page(pgd_t pgd)
256 { return PAGE_OFFSET + ((pgd_val(pgd) & _PFN_MASK) >> (32-PAGE_SHIFT)); }
257
258 extern inline int pte_none(pte_t pte) { return !pte_val(pte); }
259 extern inline int pte_present(pte_t pte) { return pte_val(pte) & _PAGE_VALID; }
260 extern inline void pte_clear(pte_t *ptep) { pte_val(*ptep) = 0; }
261
262 extern inline int pmd_none(pmd_t pmd) { return !pmd_val(pmd); }
263 extern inline int pmd_bad(pmd_t pmd) { return (pmd_val(pmd) & ~_PFN_MASK) != _PAGE_TABLE; }
264 extern inline int pmd_present(pmd_t pmd) { return pmd_val(pmd) & _PAGE_VALID; }
265 extern inline void pmd_clear(pmd_t * pmdp) { pmd_val(*pmdp) = 0; }
266
267 extern inline int pgd_none(pgd_t pgd) { return !pgd_val(pgd); }
268 extern inline int pgd_bad(pgd_t pgd) { return (pgd_val(pgd) & ~_PFN_MASK) != _PAGE_TABLE; }
269 extern inline int pgd_present(pgd_t pgd) { return pgd_val(pgd) & _PAGE_VALID; }
270 extern inline void pgd_clear(pgd_t * pgdp) { pgd_val(*pgdp) = 0; }
271
272 #define page_address(page) ((page)->virtual)
273
274 /*
275 * The following only work if pte_present() is true.
276 * Undefined behaviour if not..
277 */
278 extern inline int pte_read(pte_t pte) { return !(pte_val(pte) & _PAGE_FOR); }
279 extern inline int pte_write(pte_t pte) { return !(pte_val(pte) & _PAGE_FOW); }
280 extern inline int pte_exec(pte_t pte) { return !(pte_val(pte) & _PAGE_FOE); }
281 extern inline int pte_dirty(pte_t pte) { return pte_val(pte) & _PAGE_DIRTY; }
282 extern inline int pte_young(pte_t pte) { return pte_val(pte) & _PAGE_ACCESSED; }
283
284 extern inline pte_t pte_wrprotect(pte_t pte) { pte_val(pte) |= _PAGE_FOW; return pte; }
285 extern inline pte_t pte_rdprotect(pte_t pte) { pte_val(pte) |= _PAGE_FOR; return pte; }
286 extern inline pte_t pte_exprotect(pte_t pte) { pte_val(pte) |= _PAGE_FOE; return pte; }
287 extern inline pte_t pte_mkclean(pte_t pte) { pte_val(pte) &= ~(__DIRTY_BITS); return pte; }
288 extern inline pte_t pte_mkold(pte_t pte) { pte_val(pte) &= ~(__ACCESS_BITS); return pte; }
289 extern inline pte_t pte_mkwrite(pte_t pte) { pte_val(pte) &= ~_PAGE_FOW; return pte; }
290 extern inline pte_t pte_mkread(pte_t pte) { pte_val(pte) &= ~_PAGE_FOR; return pte; }
291 extern inline pte_t pte_mkexec(pte_t pte) { pte_val(pte) &= ~_PAGE_FOE; return pte; }
292 extern inline pte_t pte_mkdirty(pte_t pte) { pte_val(pte) |= __DIRTY_BITS; return pte; }
293 extern inline pte_t pte_mkyoung(pte_t pte) { pte_val(pte) |= __ACCESS_BITS; return pte; }
294
295 #define PAGE_DIR_OFFSET(tsk,address) pgd_offset((tsk),(address))
296
297 /* to find an entry in a kernel page-table-directory */
298 #define pgd_offset_k(address) pgd_offset(&init_mm, address)
299
300 /* to find an entry in a page-table-directory. */
301 #define pgd_index(address) ((address >> PGDIR_SHIFT) & (PTRS_PER_PGD - 1))
302 #define __pgd_offset(address) pgd_index(address)
303 #define pgd_offset(mm, address) ((mm)->pgd+pgd_index(address))
304
305 /* Find an entry in the second-level page table.. */
306 extern inline pmd_t * pmd_offset(pgd_t * dir, unsigned long address)
307 {
308 return (pmd_t *) pgd_page(*dir) + ((address >> PMD_SHIFT) & (PTRS_PER_PAGE - 1));
309 }
310
311 /* Find an entry in the third-level page table.. */
312 extern inline pte_t * pte_offset(pmd_t * dir, unsigned long address)
313 {
314 return (pte_t *) pmd_page(*dir) + ((address >> PAGE_SHIFT) & (PTRS_PER_PAGE - 1));
315 }
316
317 extern pgd_t swapper_pg_dir[1024];
318
319 /*
320 * The Alpha doesn't have any external MMU info: the kernel page
321 * tables contain all the necessary information.
322 */
323 extern inline void update_mmu_cache(struct vm_area_struct * vma,
324 unsigned long address, pte_t pte)
325 {
326 }
327
328 /*
329 * Non-present pages: high 24 bits are offset, next 8 bits type,
330 * low 32 bits zero.
331 */
332 extern inline pte_t mk_swap_pte(unsigned long type, unsigned long offset)
333 { pte_t pte; pte_val(pte) = (type << 32) | (offset << 40); return pte; }
334
335 #define SWP_TYPE(x) (((x).val >> 32) & 0xff)
336 #define SWP_OFFSET(x) ((x).val >> 40)
337 #define SWP_ENTRY(type, offset) ((swp_entry_t) { pte_val(mk_swap_pte((type),(offset))) })
338 #define pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
339 #define swp_entry_to_pte(x) ((pte_t) { (x).val })
340
341 /* Needs to be defined here and not in linux/mm.h, as it is arch dependent */
342 #define PageSkip(page) (0)
343
344 #ifndef CONFIG_DISCONTIGMEM
345 #define kern_addr_valid(addr) (1)
346 #endif
347
348 #define io_remap_page_range(start, busaddr, size, prot) \
349 remap_page_range(start, virt_to_phys(__ioremap(busaddr, size)), size, prot)
350
351 #define pte_ERROR(e) \
352 printk("%s:%d: bad pte %016lx.\n", __FILE__, __LINE__, pte_val(e))
353 #define pmd_ERROR(e) \
354 printk("%s:%d: bad pmd %016lx.\n", __FILE__, __LINE__, pmd_val(e))
355 #define pgd_ERROR(e) \
356 printk("%s:%d: bad pgd %016lx.\n", __FILE__, __LINE__, pgd_val(e))
357
358 extern void paging_init(void);
359
360 #include <asm-generic/pgtable.h>
361
362 /*
363 * No page table caches to initialise
364 */
365 #define pgtable_cache_init() do { } while (0)
366
367 #endif /* _ALPHA_PGTABLE_H */
368