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
13 #include <asm/page.h>
14 #include <asm/processor.h> /* For TASK_SIZE */
15 #include <asm/machvec.h>
16
17 /* Certain architectures need to do special things when PTEs
18 * within a page table are directly modified. Thus, the following
19 * hook is made available.
20 */
21 #define set_pte(pteptr, pteval) ((*(pteptr)) = (pteval))
22
23 /* PMD_SHIFT determines the size of the area a second-level page table can map */
24 #define PMD_SHIFT (PAGE_SHIFT + (PAGE_SHIFT-3))
25 #define PMD_SIZE (1UL << PMD_SHIFT)
26 #define PMD_MASK (~(PMD_SIZE-1))
27
28 /* PGDIR_SHIFT determines what a third-level page table entry can map */
29 #define PGDIR_SHIFT (PAGE_SHIFT + 2*(PAGE_SHIFT-3))
30 #define PGDIR_SIZE (1UL << PGDIR_SHIFT)
31 #define PGDIR_MASK (~(PGDIR_SIZE-1))
32
33 /*
34 * Entries per page directory level: the Alpha is three-level, with
35 * all levels having a one-page page table.
36 */
37 #define PTRS_PER_PTE (1UL << (PAGE_SHIFT-3))
38 #define PTRS_PER_PMD (1UL << (PAGE_SHIFT-3))
39 #define PTRS_PER_PGD (1UL << (PAGE_SHIFT-3))
40 #define USER_PTRS_PER_PGD (TASK_SIZE / PGDIR_SIZE)
41 #define FIRST_USER_PGD_NR 0
42
43 /* Number of pointers that fit on a page: this will go away. */
44 #define PTRS_PER_PAGE (1UL << (PAGE_SHIFT-3))
45
46 #ifdef CONFIG_ALPHA_LARGE_VMALLOC
47 #define VMALLOC_START 0xfffffe0000000000
48 #else
49 #define VMALLOC_START (-2*PGDIR_SIZE)
50 #endif
51 #define VMALLOC_VMADDR(x) ((unsigned long)(x))
52 #define VMALLOC_END (-PGDIR_SIZE)
53
54 /*
55 * OSF/1 PAL-code-imposed page table bits
56 */
57 #define _PAGE_VALID 0x0001
58 #define _PAGE_FOR 0x0002 /* used for page protection (fault on read) */
59 #define _PAGE_FOW 0x0004 /* used for page protection (fault on write) */
60 #define _PAGE_FOE 0x0008 /* used for page protection (fault on exec) */
61 #define _PAGE_ASM 0x0010
62 #if defined(CONFIG_ALPHA_EV6) && !defined(CONFIG_SMP)
63 #define _PAGE_MBE 0x0080 /* MB disable bit for EV6. */
64 #else
65 #define _PAGE_MBE 0x0000
66 #endif
67 #define _PAGE_KRE 0x0100 /* xxx - see below on the "accessed" bit */
68 #define _PAGE_URE 0x0200 /* xxx */
69 #define _PAGE_KWE 0x1000 /* used to do the dirty bit in software */
70 #define _PAGE_UWE 0x2000 /* used to do the dirty bit in software */
71
72 /* .. and these are ours ... */
73 #define _PAGE_DIRTY 0x20000
74 #define _PAGE_ACCESSED 0x40000
75
76 /*
77 * NOTE! The "accessed" bit isn't necessarily exact: it can be kept exactly
78 * by software (use the KRE/URE/KWE/UWE bits appropriately), but I'll fake it.
79 * Under Linux/AXP, the "accessed" bit just means "read", and I'll just use
80 * the KRE/URE bits to watch for it. That way we don't need to overload the
81 * KWE/UWE bits with both handling dirty and accessed.
82 *
83 * Note that the kernel uses the accessed bit just to check whether to page
84 * out a page or not, so it doesn't have to be exact anyway.
85 */
86
87 #define __DIRTY_BITS (_PAGE_DIRTY | _PAGE_KWE | _PAGE_UWE)
88 #define __ACCESS_BITS (_PAGE_ACCESSED | _PAGE_KRE | _PAGE_URE)
89
90 #define _PFN_MASK 0xFFFFFFFF00000000
91
92 #define _PAGE_TABLE (_PAGE_VALID | __DIRTY_BITS | __ACCESS_BITS)
93 #define _PAGE_CHG_MASK (_PFN_MASK | __DIRTY_BITS | __ACCESS_BITS | _PAGE_MBE)
94
95 /*
96 * All the normal masks have the "page accessed" bits on, as any time they
97 * are used, the page is accessed. They are cleared only by the page-out
98 * routines.
99 */
100 #define PAGE_NONE __pgprot(_PAGE_VALID | __ACCESS_BITS | _PAGE_FOR | _PAGE_FOW | _PAGE_FOE)
101 #define PAGE_SHARED __pgprot(_PAGE_VALID | __ACCESS_BITS)
102 #define PAGE_COPY __pgprot(_PAGE_VALID | __ACCESS_BITS | _PAGE_FOW)
103 #define PAGE_READONLY __pgprot(_PAGE_VALID | __ACCESS_BITS | _PAGE_FOW)
104 #define PAGE_KERNEL __pgprot(_PAGE_VALID | _PAGE_ASM | _PAGE_KRE | _PAGE_KWE | _PAGE_MBE)
105
106 #define _PAGE_NORMAL(x) __pgprot(_PAGE_VALID | __ACCESS_BITS | _PAGE_MBE | (x))
107
108 #define _PAGE_P(x) _PAGE_NORMAL((x) | (((x) & _PAGE_FOW)?0:_PAGE_FOW))
109 #define _PAGE_S(x) _PAGE_NORMAL(x)
110
111 /*
112 * The hardware can handle write-only mappings, but as the Alpha
113 * architecture does byte-wide writes with a read-modify-write
114 * sequence, it's not practical to have write-without-read privs.
115 * Thus the "-w- -> rw-" and "-wx -> rwx" mapping here (and in
116 * arch/alpha/mm/fault.c)
117 */
118 /* xwr */
119 #define __P000 _PAGE_P(_PAGE_FOE | _PAGE_FOW | _PAGE_FOR)
120 #define __P001 _PAGE_P(_PAGE_FOE | _PAGE_FOW)
121 #define __P010 _PAGE_P(_PAGE_FOE)
122 #define __P011 _PAGE_P(_PAGE_FOE)
123 #define __P100 _PAGE_P(_PAGE_FOW | _PAGE_FOR)
124 #define __P101 _PAGE_P(_PAGE_FOW)
125 #define __P110 _PAGE_P(0)
126 #define __P111 _PAGE_P(0)
127
128 #define __S000 _PAGE_S(_PAGE_FOE | _PAGE_FOW | _PAGE_FOR)
129 #define __S001 _PAGE_S(_PAGE_FOE | _PAGE_FOW)
130 #define __S010 _PAGE_S(_PAGE_FOE)
131 #define __S011 _PAGE_S(_PAGE_FOE)
132 #define __S100 _PAGE_S(_PAGE_FOW | _PAGE_FOR)
133 #define __S101 _PAGE_S(_PAGE_FOW)
134 #define __S110 _PAGE_S(0)
135 #define __S111 _PAGE_S(0)
136
137 /*
138 * BAD_PAGETABLE is used when we need a bogus page-table, while
139 * BAD_PAGE is used for a bogus page.
140 *
141 * ZERO_PAGE is a global shared page that is always zero: used
142 * for zero-mapped memory areas etc..
143 */
144 extern pte_t __bad_page(void);
145 extern pmd_t * __bad_pagetable(void);
146
147 extern unsigned long __zero_page(void);
148
149 #define BAD_PAGETABLE __bad_pagetable()
150 #define BAD_PAGE __bad_page()
151 #define ZERO_PAGE(vaddr) (virt_to_page(ZERO_PGE))
152
153 /* number of bits that fit into a memory pointer */
154 #define BITS_PER_PTR (8*sizeof(unsigned long))
155
156 /* to align the pointer to a pointer address */
157 #define PTR_MASK (~(sizeof(void*)-1))
158
159 /* sizeof(void*)==1<<SIZEOF_PTR_LOG2 */
160 #define SIZEOF_PTR_LOG2 3
161
162 /* to find an entry in a page-table */
163 #define PAGE_PTR(address) \
164 ((unsigned long)(address)>>(PAGE_SHIFT-SIZEOF_PTR_LOG2)&PTR_MASK&~PAGE_MASK)
165
166 /*
167 * On certain platforms whose physical address space can overlap KSEG,
168 * namely EV6 and above, we must re-twiddle the physaddr to restore the
169 * correct high-order bits.
170 *
171 * This is extremely confusing until you realize that this is actually
172 * just working around a userspace bug. The X server was intending to
173 * provide the physical address but instead provided the KSEG address.
174 * Or tried to, except it's not representable.
175 *
176 * On Tsunami there's nothing meaningful at 0x40000000000, so this is
177 * a safe thing to do. Come the first core logic that does put something
178 * in this area -- memory or whathaveyou -- then this hack will have
179 * to go away. So be prepared!
180 */
181
182 #if defined(CONFIG_ALPHA_GENERIC) && defined(USE_48_BIT_KSEG)
183 #error "EV6-only feature in a generic kernel"
184 #endif
185 #if defined(CONFIG_ALPHA_GENERIC) || \
186 (defined(CONFIG_ALPHA_EV6) && !defined(USE_48_BIT_KSEG))
187 #define PHYS_TWIDDLE(phys) \
188 ((((phys) & 0xc0000000000UL) == 0x40000000000UL) \
189 ? ((phys) ^= 0xc0000000000UL) : (phys))
190 #else
191 #define PHYS_TWIDDLE(phys) (phys)
192 #endif
193
194 /*
195 * Conversion functions: convert a page and protection to a page entry,
196 * and a page entry and page directory to the page they refer to.
197 */
198
199 #define mk_pte(page, pgprot) \
200 ({ \
201 pte_t pte; \
202 \
203 pte_val(pte) = ((unsigned long)(page - mem_map) << 32) | \
204 pgprot_val(pgprot); \
205 pte; \
206 })
207
208 extern inline pte_t mk_pte_phys(unsigned long physpage, pgprot_t pgprot)
209 { pte_t pte; pte_val(pte) = (PHYS_TWIDDLE(physpage) << (32-PAGE_SHIFT)) | (pgprot_val(pgprot) & ~_PAGE_MBE); return pte; }
210
211 extern inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
212 { pte_val(pte) = (pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot); return pte; }
213
214 extern inline void pmd_set(pmd_t * pmdp, pte_t * ptep)
215 { pmd_val(*pmdp) = _PAGE_TABLE | ((((unsigned long) ptep) - PAGE_OFFSET) << (32-PAGE_SHIFT)); }
216
217 extern inline void pgd_set(pgd_t * pgdp, pmd_t * pmdp)
218 { pgd_val(*pgdp) = _PAGE_TABLE | ((((unsigned long) pmdp) - PAGE_OFFSET) << (32-PAGE_SHIFT)); }
219
220 #define pte_page(x) (mem_map+(unsigned long)((pte_val(x) >> 32)))
221
222 extern inline unsigned long pmd_page(pmd_t pmd)
223 { return PAGE_OFFSET + ((pmd_val(pmd) & _PFN_MASK) >> (32-PAGE_SHIFT)); }
224
225 extern inline unsigned long pgd_page(pgd_t pgd)
226 { return PAGE_OFFSET + ((pgd_val(pgd) & _PFN_MASK) >> (32-PAGE_SHIFT)); }
227
228 extern inline int pte_none(pte_t pte) { return !pte_val(pte); }
229 extern inline int pte_present(pte_t pte) { return pte_val(pte) & _PAGE_VALID; }
230 extern inline void pte_clear(pte_t *ptep) { pte_val(*ptep) = 0; }
231
232 extern inline int pmd_none(pmd_t pmd) { return !pmd_val(pmd); }
233 extern inline int pmd_bad(pmd_t pmd) { return (pmd_val(pmd) & ~_PFN_MASK) != _PAGE_TABLE; }
234 extern inline int pmd_present(pmd_t pmd) { return pmd_val(pmd) & _PAGE_VALID; }
235 extern inline void pmd_clear(pmd_t * pmdp) { pmd_val(*pmdp) = 0; }
236
237 extern inline int pgd_none(pgd_t pgd) { return !pgd_val(pgd); }
238 extern inline int pgd_bad(pgd_t pgd) { return (pgd_val(pgd) & ~_PFN_MASK) != _PAGE_TABLE; }
239 extern inline int pgd_present(pgd_t pgd) { return pgd_val(pgd) & _PAGE_VALID; }
240 extern inline void pgd_clear(pgd_t * pgdp) { pgd_val(*pgdp) = 0; }
241
242 #define page_address(page) ((page)->virtual)
243
244 /*
245 * The following only work if pte_present() is true.
246 * Undefined behaviour if not..
247 */
248 extern inline int pte_read(pte_t pte) { return !(pte_val(pte) & _PAGE_FOR); }
249 extern inline int pte_write(pte_t pte) { return !(pte_val(pte) & _PAGE_FOW); }
250 extern inline int pte_exec(pte_t pte) { return !(pte_val(pte) & _PAGE_FOE); }
251 extern inline int pte_dirty(pte_t pte) { return pte_val(pte) & _PAGE_DIRTY; }
252 extern inline int pte_young(pte_t pte) { return pte_val(pte) & _PAGE_ACCESSED; }
253
254 extern inline pte_t pte_wrprotect(pte_t pte) { pte_val(pte) |= _PAGE_FOW; return pte; }
255 extern inline pte_t pte_rdprotect(pte_t pte) { pte_val(pte) |= _PAGE_FOR; return pte; }
256 extern inline pte_t pte_exprotect(pte_t pte) { pte_val(pte) |= _PAGE_FOE; return pte; }
257 extern inline pte_t pte_mkclean(pte_t pte) { pte_val(pte) &= ~(__DIRTY_BITS); return pte; }
258 extern inline pte_t pte_mkold(pte_t pte) { pte_val(pte) &= ~(__ACCESS_BITS); return pte; }
259 extern inline pte_t pte_mkwrite(pte_t pte) { pte_val(pte) &= ~_PAGE_FOW; return pte; }
260 extern inline pte_t pte_mkread(pte_t pte) { pte_val(pte) &= ~_PAGE_FOR; return pte; }
261 extern inline pte_t pte_mkexec(pte_t pte) { pte_val(pte) &= ~_PAGE_FOE; return pte; }
262 extern inline pte_t pte_mkdirty(pte_t pte) { pte_val(pte) |= __DIRTY_BITS; return pte; }
263 extern inline pte_t pte_mkyoung(pte_t pte) { pte_val(pte) |= __ACCESS_BITS; return pte; }
264
265 #define PAGE_DIR_OFFSET(tsk,address) pgd_offset((tsk),(address))
266
267 /* to find an entry in a kernel page-table-directory */
268 #define pgd_offset_k(address) pgd_offset(&init_mm, address)
269
270 /* to find an entry in a page-table-directory. */
271 #define pgd_index(address) ((address >> PGDIR_SHIFT) & (PTRS_PER_PGD - 1))
272 #define __pgd_offset(address) pgd_index(address)
273 #define pgd_offset(mm, address) ((mm)->pgd+pgd_index(address))
274
275 /* Find an entry in the second-level page table.. */
276 extern inline pmd_t * pmd_offset(pgd_t * dir, unsigned long address)
277 {
278 return (pmd_t *) pgd_page(*dir) + ((address >> PMD_SHIFT) & (PTRS_PER_PAGE - 1));
279 }
280
281 /* Find an entry in the third-level page table.. */
282 extern inline pte_t * pte_offset(pmd_t * dir, unsigned long address)
283 {
284 return (pte_t *) pmd_page(*dir) + ((address >> PAGE_SHIFT) & (PTRS_PER_PAGE - 1));
285 }
286
287 extern pgd_t swapper_pg_dir[1024];
288
289 /*
290 * The Alpha doesn't have any external MMU info: the kernel page
291 * tables contain all the necessary information.
292 */
293 extern inline void update_mmu_cache(struct vm_area_struct * vma,
294 unsigned long address, pte_t pte)
295 {
296 }
297
298 /*
299 * Non-present pages: high 24 bits are offset, next 8 bits type,
300 * low 32 bits zero.
301 */
302 extern inline pte_t mk_swap_pte(unsigned long type, unsigned long offset)
303 { pte_t pte; pte_val(pte) = (type << 32) | (offset << 40); return pte; }
304
305 #define SWP_TYPE(x) (((x).val >> 32) & 0xff)
306 #define SWP_OFFSET(x) ((x).val >> 40)
307 #define SWP_ENTRY(type, offset) ((swp_entry_t) { pte_val(mk_swap_pte((type),(offset))) })
308 #define pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
309 #define swp_entry_to_pte(x) ((pte_t) { (x).val })
310
311 /* Needs to be defined here and not in linux/mm.h, as it is arch dependent */
312 #define PageSkip(page) (0)
313 #define kern_addr_valid(addr) (1)
314
315 #define io_remap_page_range(start, busaddr, size, prot) \
316 remap_page_range(start, virt_to_phys(__ioremap(busaddr)), size, prot)
317
318 #define pte_ERROR(e) \
319 printk("%s:%d: bad pte %016lx.\n", __FILE__, __LINE__, pte_val(e))
320 #define pmd_ERROR(e) \
321 printk("%s:%d: bad pmd %016lx.\n", __FILE__, __LINE__, pmd_val(e))
322 #define pgd_ERROR(e) \
323 printk("%s:%d: bad pgd %016lx.\n", __FILE__, __LINE__, pgd_val(e))
324
325 extern void paging_init(void);
326
327 #include <asm-generic/pgtable.h>
328
329 #endif /* _ALPHA_PGTABLE_H */
330
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