1 #ifndef _ALPHA_PGTABLE_H
2 #define _ALPHA_PGTABLE_H
5 * This file contains the functions and defines necessary to modify and use
6 * the Alpha page table tree.
8 * This hopefully works with any standard Alpha page-size, as defined
9 * in <asm/page.h> (currently 8192).
11 #include <linux/config.h>
12 #include <linux/mmzone.h>
15 #include <asm/processor.h> /* For TASK_SIZE */
16 #include <asm/machvec.h>
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.
22 #define set_pte(pteptr, pteval) ((*(pteptr)) = (pteval))
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))
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))
35 * Entries per page directory level: the Alpha is three-level, with
36 * all levels having a one-page page table.
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
44 /* Number of pointers that fit on a page: this will go away. */
45 #define PTRS_PER_PAGE (1UL << (PAGE_SHIFT-3))
47 #ifdef CONFIG_ALPHA_LARGE_VMALLOC
48 #define VMALLOC_START 0xfffffe0000000000
50 #define VMALLOC_START (-2*PGDIR_SIZE)
52 #define VMALLOC_END (-PGDIR_SIZE)
55 * OSF/1 PAL-code-imposed page table bits
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 #define _PAGE_KRE 0x0100 /* xxx - see below on the "accessed" bit */
63 #define _PAGE_URE 0x0200 /* xxx */
64 #define _PAGE_KWE 0x1000 /* used to do the dirty bit in software */
65 #define _PAGE_UWE 0x2000 /* used to do the dirty bit in software */
67 /* .. and these are ours ... */
68 #define _PAGE_DIRTY 0x20000
69 #define _PAGE_ACCESSED 0x40000
70 #define _PAGE_FILE 0x80000 /* set:pagecache, unset:swap */
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.
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.
83 #define __DIRTY_BITS (_PAGE_DIRTY | _PAGE_KWE | _PAGE_UWE)
84 #define __ACCESS_BITS (_PAGE_ACCESSED | _PAGE_KRE | _PAGE_URE)
86 #define _PFN_MASK 0xFFFFFFFF00000000UL
88 #define _PAGE_TABLE (_PAGE_VALID | __DIRTY_BITS | __ACCESS_BITS)
89 #define _PAGE_CHG_MASK (_PFN_MASK | __DIRTY_BITS | __ACCESS_BITS)
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
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)
101 #define _PAGE_NORMAL(x) __pgprot(_PAGE_VALID | __ACCESS_BITS | (x))
103 #define _PAGE_P(x) _PAGE_NORMAL((x) | (((x) & _PAGE_FOW)?0:_PAGE_FOW))
104 #define _PAGE_S(x) _PAGE_NORMAL(x)
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)
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)
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)
133 * BAD_PAGETABLE is used when we need a bogus page-table, while
134 * BAD_PAGE is used for a bogus page.
136 * ZERO_PAGE is a global shared page that is always zero: used
137 * for zero-mapped memory areas etc..
139 extern pte_t __bad_page(void);
140 extern pmd_t * __bad_pagetable(void);
142 extern unsigned long __zero_page(void);
144 #define BAD_PAGETABLE __bad_pagetable()
145 #define BAD_PAGE __bad_page()
146 #define ZERO_PAGE(vaddr) (virt_to_page(ZERO_PGE))
148 /* number of bits that fit into a memory pointer */
149 #define BITS_PER_PTR (8*sizeof(unsigned long))
151 /* to align the pointer to a pointer address */
152 #define PTR_MASK (~(sizeof(void*)-1))
154 /* sizeof(void*)==1<<SIZEOF_PTR_LOG2 */
155 #define SIZEOF_PTR_LOG2 3
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)
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.
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.
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!
177 #if defined(CONFIG_ALPHA_GENERIC) && defined(USE_48_BIT_KSEG)
178 #error "EV6-only feature in a generic kernel"
180 #if defined(CONFIG_ALPHA_GENERIC) || \
181 (defined(CONFIG_ALPHA_EV6) && !defined(USE_48_BIT_KSEG))
182 #define KSEG_PFN (0xc0000000000UL >> PAGE_SHIFT)
183 #define PHYS_TWIDDLE(pfn) \
184 ((((pfn) & KSEG_PFN) == (0x40000000000UL >> PAGE_SHIFT)) \
185 ? ((pfn) ^= KSEG_PFN) : (pfn))
187 #define PHYS_TWIDDLE(pfn) (pfn)
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.
194 #ifndef CONFIG_DISCONTIGMEM
195 #define page_to_pa(page) ((page - mem_map) << PAGE_SHIFT)
197 #define pte_pfn(pte) (pte_val(pte) >> 32)
198 #define pte_page(pte) pfn_to_page(pte_pfn(pte))
199 #define mk_pte(page, pgprot) \
203 pte_val(pte) = (page_to_pfn(page) << 32) | pgprot_val(pgprot); \
208 extern inline pte_t pfn_pte(unsigned long physpfn, pgprot_t pgprot)
209 { pte_t pte; pte_val(pte) = (PHYS_TWIDDLE(physpfn) << 32) | pgprot_val(pgprot); return pte; }
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; }
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)); }
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)); }
221 extern inline unsigned long
222 pmd_page_kernel(pmd_t pmd)
224 return ((pmd_val(pmd) & _PFN_MASK) >> (32-PAGE_SHIFT)) + PAGE_OFFSET;
227 #ifndef CONFIG_DISCONTIGMEM
228 #define pmd_page(pmd) (mem_map + ((pmd_val(pmd) & _PFN_MASK) >> 32))
231 extern inline unsigned long pgd_page(pgd_t pgd)
232 { return PAGE_OFFSET + ((pgd_val(pgd) & _PFN_MASK) >> (32-PAGE_SHIFT)); }
234 extern inline int pte_none(pte_t pte) { return !pte_val(pte); }
235 extern inline int pte_present(pte_t pte) { return pte_val(pte) & _PAGE_VALID; }
236 extern inline void pte_clear(pte_t *ptep) { pte_val(*ptep) = 0; }
238 extern inline int pmd_none(pmd_t pmd) { return !pmd_val(pmd); }
239 extern inline int pmd_bad(pmd_t pmd) { return (pmd_val(pmd) & ~_PFN_MASK) != _PAGE_TABLE; }
240 extern inline int pmd_present(pmd_t pmd) { return pmd_val(pmd) & _PAGE_VALID; }
241 extern inline void pmd_clear(pmd_t * pmdp) { pmd_val(*pmdp) = 0; }
243 extern inline int pgd_none(pgd_t pgd) { return !pgd_val(pgd); }
244 extern inline int pgd_bad(pgd_t pgd) { return (pgd_val(pgd) & ~_PFN_MASK) != _PAGE_TABLE; }
245 extern inline int pgd_present(pgd_t pgd) { return pgd_val(pgd) & _PAGE_VALID; }
246 extern inline void pgd_clear(pgd_t * pgdp) { pgd_val(*pgdp) = 0; }
249 * The following only work if pte_present() is true.
250 * Undefined behaviour if not..
252 extern inline int pte_read(pte_t pte) { return !(pte_val(pte) & _PAGE_FOR); }
253 extern inline int pte_write(pte_t pte) { return !(pte_val(pte) & _PAGE_FOW); }
254 extern inline int pte_exec(pte_t pte) { return !(pte_val(pte) & _PAGE_FOE); }
255 extern inline int pte_dirty(pte_t pte) { return pte_val(pte) & _PAGE_DIRTY; }
256 extern inline int pte_young(pte_t pte) { return pte_val(pte) & _PAGE_ACCESSED; }
257 extern inline int pte_file(pte_t pte) { return pte_val(pte) & _PAGE_FILE; }
259 extern inline pte_t pte_wrprotect(pte_t pte) { pte_val(pte) |= _PAGE_FOW; return pte; }
260 extern inline pte_t pte_rdprotect(pte_t pte) { pte_val(pte) |= _PAGE_FOR; return pte; }
261 extern inline pte_t pte_exprotect(pte_t pte) { pte_val(pte) |= _PAGE_FOE; return pte; }
262 extern inline pte_t pte_mkclean(pte_t pte) { pte_val(pte) &= ~(__DIRTY_BITS); return pte; }
263 extern inline pte_t pte_mkold(pte_t pte) { pte_val(pte) &= ~(__ACCESS_BITS); return pte; }
264 extern inline pte_t pte_mkwrite(pte_t pte) { pte_val(pte) &= ~_PAGE_FOW; return pte; }
265 extern inline pte_t pte_mkread(pte_t pte) { pte_val(pte) &= ~_PAGE_FOR; return pte; }
266 extern inline pte_t pte_mkexec(pte_t pte) { pte_val(pte) &= ~_PAGE_FOE; return pte; }
267 extern inline pte_t pte_mkdirty(pte_t pte) { pte_val(pte) |= __DIRTY_BITS; return pte; }
268 extern inline pte_t pte_mkyoung(pte_t pte) { pte_val(pte) |= __ACCESS_BITS; return pte; }
270 #define PAGE_DIR_OFFSET(tsk,address) pgd_offset((tsk),(address))
272 /* to find an entry in a kernel page-table-directory */
273 #define pgd_offset_k(address) pgd_offset(&init_mm, address)
275 /* to find an entry in a page-table-directory. */
276 #define pgd_index(address) ((address >> PGDIR_SHIFT) & (PTRS_PER_PGD - 1))
277 #define pgd_offset(mm, address) ((mm)->pgd+pgd_index(address))
279 /* Find an entry in the second-level page table.. */
280 extern inline pmd_t * pmd_offset(pgd_t * dir, unsigned long address)
282 return (pmd_t *) pgd_page(*dir) + ((address >> PMD_SHIFT) & (PTRS_PER_PAGE - 1));
285 /* Find an entry in the third-level page table.. */
286 extern inline pte_t * pte_offset_kernel(pmd_t * dir, unsigned long address)
288 return (pte_t *) pmd_page_kernel(*dir)
289 + ((address >> PAGE_SHIFT) & (PTRS_PER_PAGE - 1));
292 #define pte_offset_map(dir,addr) pte_offset_kernel((dir),(addr))
293 #define pte_offset_map_nested(dir,addr) pte_offset_kernel((dir),(addr))
294 #define pte_unmap(pte) do { } while (0)
295 #define pte_unmap_nested(pte) do { } while (0)
297 extern pgd_t swapper_pg_dir[1024];
300 * The Alpha doesn't have any external MMU info: the kernel page
301 * tables contain all the necessary information.
303 extern inline void update_mmu_cache(struct vm_area_struct * vma,
304 unsigned long address, pte_t pte)
309 * Non-present pages: high 24 bits are offset, next 8 bits type,
312 extern inline pte_t mk_swap_pte(unsigned long type, unsigned long offset)
313 { pte_t pte; pte_val(pte) = (type << 32) | (offset << 40); return pte; }
315 #define __swp_type(x) (((x).val >> 32) & 0xff)
316 #define __swp_offset(x) ((x).val >> 40)
317 #define __swp_entry(type, off) ((swp_entry_t) { pte_val(mk_swap_pte((type), (off))) })
318 #define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
319 #define __swp_entry_to_pte(x) ((pte_t) { (x).val })
321 #define pte_to_pgoff(pte) (pte_val(pte) >> 32)
322 #define pgoff_to_pte(off) ((pte_t) { ((off) << 32) | _PAGE_FILE })
324 #define PTE_FILE_MAX_BITS 32
326 #ifndef CONFIG_DISCONTIGMEM
327 #define kern_addr_valid(addr) (1)
330 #define io_remap_page_range(vma, start, busaddr, size, prot) \
331 remap_page_range(vma, start, virt_to_phys(__ioremap(busaddr, size)), size, prot)
333 #define pte_ERROR(e) \
334 printk("%s:%d: bad pte %016lx.\n", __FILE__, __LINE__, pte_val(e))
335 #define pmd_ERROR(e) \
336 printk("%s:%d: bad pmd %016lx.\n", __FILE__, __LINE__, pmd_val(e))
337 #define pgd_ERROR(e) \
338 printk("%s:%d: bad pgd %016lx.\n", __FILE__, __LINE__, pgd_val(e))
340 extern void paging_init(void);
342 #include <asm-generic/pgtable.h>
345 * No page table caches to initialise
347 #define pgtable_cache_init() do { } while (0)
349 /* We have our own get_unmapped_area to cope with ADDR_LIMIT_32BIT. */
350 #define HAVE_ARCH_UNMAPPED_AREA
352 #endif /* _ALPHA_PGTABLE_H */