1 #ifndef _ALPHA_PGTABLE_H
2 #define _ALPHA_PGTABLE_H
3
4 #include <asm-generic/4level-fixup.h>
5
6 /*
7 * This file contains the functions and defines necessary to modify and use
8 * the Alpha page table tree.
9 *
10 * This hopefully works with any standard Alpha page-size, as defined
11 * in <asm/page.h> (currently 8192).
12 */
13 #include <linux/mmzone.h>
14
15 #include <asm/page.h>
16 #include <asm/processor.h> /* For TASK_SIZE */
17 #include <asm/machvec.h>
18
19 struct mm_struct;
20 struct vm_area_struct;
21
22 /* Certain architectures need to do special things when PTEs
23 * within a page table are directly modified. Thus, the following
24 * hook is made available.
25 */
26 #define set_pte(pteptr, pteval) ((*(pteptr)) = (pteval))
27 #define set_pte_at(mm,addr,ptep,pteval) set_pte(ptep,pteval)
28
29 /* PMD_SHIFT determines the size of the area a second-level page table can map */
30 #define PMD_SHIFT (PAGE_SHIFT + (PAGE_SHIFT-3))
31 #define PMD_SIZE (1UL << PMD_SHIFT)
32 #define PMD_MASK (~(PMD_SIZE-1))
33
34 /* PGDIR_SHIFT determines what a third-level page table entry can map */
35 #define PGDIR_SHIFT (PAGE_SHIFT + 2*(PAGE_SHIFT-3))
36 #define PGDIR_SIZE (1UL << PGDIR_SHIFT)
37 #define PGDIR_MASK (~(PGDIR_SIZE-1))
38
39 /*
40 * Entries per page directory level: the Alpha is three-level, with
41 * all levels having a one-page page table.
42 */
43 #define PTRS_PER_PTE (1UL << (PAGE_SHIFT-3))
44 #define PTRS_PER_PMD (1UL << (PAGE_SHIFT-3))
45 #define PTRS_PER_PGD (1UL << (PAGE_SHIFT-3))
46 #define USER_PTRS_PER_PGD (TASK_SIZE / PGDIR_SIZE)
47 #define FIRST_USER_ADDRESS 0
48
49 /* Number of pointers that fit on a page: this will go away. */
50 #define PTRS_PER_PAGE (1UL << (PAGE_SHIFT-3))
51
52 #ifdef CONFIG_ALPHA_LARGE_VMALLOC
53 #define VMALLOC_START 0xfffffe0000000000
54 #else
55 #define VMALLOC_START (-2*PGDIR_SIZE)
56 #endif
57 #define VMALLOC_END (-PGDIR_SIZE)
58
59 /*
60 * OSF/1 PAL-code-imposed page table bits
61 */
62 #define _PAGE_VALID 0x0001
63 #define _PAGE_FOR 0x0002 /* used for page protection (fault on read) */
64 #define _PAGE_FOW 0x0004 /* used for page protection (fault on write) */
65 #define _PAGE_FOE 0x0008 /* used for page protection (fault on exec) */
66 #define _PAGE_ASM 0x0010
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 #define _PAGE_FILE 0x80000 /* set:pagecache, unset:swap */
76
77 /*
78 * NOTE! The "accessed" bit isn't necessarily exact: it can be kept exactly
79 * by software (use the KRE/URE/KWE/UWE bits appropriately), but I'll fake it.
80 * Under Linux/AXP, the "accessed" bit just means "read", and I'll just use
81 * the KRE/URE bits to watch for it. That way we don't need to overload the
82 * KWE/UWE bits with both handling dirty and accessed.
83 *
84 * Note that the kernel uses the accessed bit just to check whether to page
85 * out a page or not, so it doesn't have to be exact anyway.
86 */
87
88 #define __DIRTY_BITS (_PAGE_DIRTY | _PAGE_KWE | _PAGE_UWE)
89 #define __ACCESS_BITS (_PAGE_ACCESSED | _PAGE_KRE | _PAGE_URE)
90
91 #define _PFN_MASK 0xFFFFFFFF00000000UL
92
93 #define _PAGE_TABLE (_PAGE_VALID | __DIRTY_BITS | __ACCESS_BITS)
94 #define _PAGE_CHG_MASK (_PFN_MASK | __DIRTY_BITS | __ACCESS_BITS)
95
96 /*
97 * All the normal masks have the "page accessed" bits on, as any time they are used,
98 * the page is accessed. They are cleared only by the page-out 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)
105
106 #define _PAGE_NORMAL(x) __pgprot(_PAGE_VALID | __ACCESS_BITS | (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 * pgprot_noncached() is only for infiniband pci support, and a real
139 * implementation for RAM would be more complicated.
140 */
141 #define pgprot_noncached(prot) (prot)
142
143 /*
144 * BAD_PAGETABLE is used when we need a bogus page-table, while
145 * BAD_PAGE is used for a bogus page.
146 *
147 * ZERO_PAGE is a global shared page that is always zero: used
148 * for zero-mapped memory areas etc..
149 */
150 extern pte_t __bad_page(void);
151 extern pmd_t * __bad_pagetable(void);
152
153 extern unsigned long __zero_page(void);
154
155 #define BAD_PAGETABLE __bad_pagetable()
156 #define BAD_PAGE __bad_page()
157 #define ZERO_PAGE(vaddr) (virt_to_page(ZERO_PGE))
158
159 /* number of bits that fit into a memory pointer */
160 #define BITS_PER_PTR (8*sizeof(unsigned long))
161
162 /* to align the pointer to a pointer address */
163 #define PTR_MASK (~(sizeof(void*)-1))
164
165 /* sizeof(void*)==1<<SIZEOF_PTR_LOG2 */
166 #define SIZEOF_PTR_LOG2 3
167
168 /* to find an entry in a page-table */
169 #define PAGE_PTR(address) \
170 ((unsigned long)(address)>>(PAGE_SHIFT-SIZEOF_PTR_LOG2)&PTR_MASK&~PAGE_MASK)
171
172 /*
173 * On certain platforms whose physical address space can overlap KSEG,
174 * namely EV6 and above, we must re-twiddle the physaddr to restore the
175 * correct high-order bits.
176 *
177 * This is extremely confusing until you realize that this is actually
178 * just working around a userspace bug. The X server was intending to
179 * provide the physical address but instead provided the KSEG address.
180 * Or tried to, except it's not representable.
181 *
182 * On Tsunami there's nothing meaningful at 0x40000000000, so this is
183 * a safe thing to do. Come the first core logic that does put something
184 * in this area -- memory or whathaveyou -- then this hack will have
185 * to go away. So be prepared!
186 */
187
188 #if defined(CONFIG_ALPHA_GENERIC) && defined(USE_48_BIT_KSEG)
189 #error "EV6-only feature in a generic kernel"
190 #endif
191 #if defined(CONFIG_ALPHA_GENERIC) || \
192 (defined(CONFIG_ALPHA_EV6) && !defined(USE_48_BIT_KSEG))
193 #define KSEG_PFN (0xc0000000000UL >> PAGE_SHIFT)
194 #define PHYS_TWIDDLE(pfn) \
195 ((((pfn) & KSEG_PFN) == (0x40000000000UL >> PAGE_SHIFT)) \
196 ? ((pfn) ^= KSEG_PFN) : (pfn))
197 #else
198 #define PHYS_TWIDDLE(pfn) (pfn)
199 #endif
200
201 /*
202 * Conversion functions: convert a page and protection to a page entry,
203 * and a page entry and page directory to the page they refer to.
204 */
205 #ifndef CONFIG_DISCONTIGMEM
206 #define page_to_pa(page) (((page) - mem_map) << PAGE_SHIFT)
207
208 #define pte_pfn(pte) (pte_val(pte) >> 32)
209 #define pte_page(pte) pfn_to_page(pte_pfn(pte))
210 #define mk_pte(page, pgprot) \
211 ({ \
212 pte_t pte; \
213 \
214 pte_val(pte) = (page_to_pfn(page) << 32) | pgprot_val(pgprot); \
215 pte; \
216 })
217 #endif
218
pfn_pte(unsigned long physpfn,pgprot_t pgprot)219 extern inline pte_t pfn_pte(unsigned long physpfn, pgprot_t pgprot)
220 { pte_t pte; pte_val(pte) = (PHYS_TWIDDLE(physpfn) << 32) | pgprot_val(pgprot); return pte; }
221
pte_modify(pte_t pte,pgprot_t newprot)222 extern inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
223 { pte_val(pte) = (pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot); return pte; }
224
pmd_set(pmd_t * pmdp,pte_t * ptep)225 extern inline void pmd_set(pmd_t * pmdp, pte_t * ptep)
226 { pmd_val(*pmdp) = _PAGE_TABLE | ((((unsigned long) ptep) - PAGE_OFFSET) << (32-PAGE_SHIFT)); }
227
pgd_set(pgd_t * pgdp,pmd_t * pmdp)228 extern inline void pgd_set(pgd_t * pgdp, pmd_t * pmdp)
229 { pgd_val(*pgdp) = _PAGE_TABLE | ((((unsigned long) pmdp) - PAGE_OFFSET) << (32-PAGE_SHIFT)); }
230
231
232 extern inline unsigned long
pmd_page_vaddr(pmd_t pmd)233 pmd_page_vaddr(pmd_t pmd)
234 {
235 return ((pmd_val(pmd) & _PFN_MASK) >> (32-PAGE_SHIFT)) + PAGE_OFFSET;
236 }
237
238 #ifndef CONFIG_DISCONTIGMEM
239 #define pmd_page(pmd) (mem_map + ((pmd_val(pmd) & _PFN_MASK) >> 32))
240 #define pgd_page(pgd) (mem_map + ((pgd_val(pgd) & _PFN_MASK) >> 32))
241 #endif
242
pgd_page_vaddr(pgd_t pgd)243 extern inline unsigned long pgd_page_vaddr(pgd_t pgd)
244 { return PAGE_OFFSET + ((pgd_val(pgd) & _PFN_MASK) >> (32-PAGE_SHIFT)); }
245
pte_none(pte_t pte)246 extern inline int pte_none(pte_t pte) { return !pte_val(pte); }
pte_present(pte_t pte)247 extern inline int pte_present(pte_t pte) { return pte_val(pte) & _PAGE_VALID; }
pte_clear(struct mm_struct * mm,unsigned long addr,pte_t * ptep)248 extern inline void pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
249 {
250 pte_val(*ptep) = 0;
251 }
252
pmd_none(pmd_t pmd)253 extern inline int pmd_none(pmd_t pmd) { return !pmd_val(pmd); }
pmd_bad(pmd_t pmd)254 extern inline int pmd_bad(pmd_t pmd) { return (pmd_val(pmd) & ~_PFN_MASK) != _PAGE_TABLE; }
pmd_present(pmd_t pmd)255 extern inline int pmd_present(pmd_t pmd) { return pmd_val(pmd) & _PAGE_VALID; }
pmd_clear(pmd_t * pmdp)256 extern inline void pmd_clear(pmd_t * pmdp) { pmd_val(*pmdp) = 0; }
257
pgd_none(pgd_t pgd)258 extern inline int pgd_none(pgd_t pgd) { return !pgd_val(pgd); }
pgd_bad(pgd_t pgd)259 extern inline int pgd_bad(pgd_t pgd) { return (pgd_val(pgd) & ~_PFN_MASK) != _PAGE_TABLE; }
pgd_present(pgd_t pgd)260 extern inline int pgd_present(pgd_t pgd) { return pgd_val(pgd) & _PAGE_VALID; }
pgd_clear(pgd_t * pgdp)261 extern inline void pgd_clear(pgd_t * pgdp) { pgd_val(*pgdp) = 0; }
262
263 /*
264 * The following only work if pte_present() is true.
265 * Undefined behaviour if not..
266 */
pte_write(pte_t pte)267 extern inline int pte_write(pte_t pte) { return !(pte_val(pte) & _PAGE_FOW); }
pte_dirty(pte_t pte)268 extern inline int pte_dirty(pte_t pte) { return pte_val(pte) & _PAGE_DIRTY; }
pte_young(pte_t pte)269 extern inline int pte_young(pte_t pte) { return pte_val(pte) & _PAGE_ACCESSED; }
pte_file(pte_t pte)270 extern inline int pte_file(pte_t pte) { return pte_val(pte) & _PAGE_FILE; }
pte_special(pte_t pte)271 extern inline int pte_special(pte_t pte) { return 0; }
272
pte_wrprotect(pte_t pte)273 extern inline pte_t pte_wrprotect(pte_t pte) { pte_val(pte) |= _PAGE_FOW; return pte; }
pte_mkclean(pte_t pte)274 extern inline pte_t pte_mkclean(pte_t pte) { pte_val(pte) &= ~(__DIRTY_BITS); return pte; }
pte_mkold(pte_t pte)275 extern inline pte_t pte_mkold(pte_t pte) { pte_val(pte) &= ~(__ACCESS_BITS); return pte; }
pte_mkwrite(pte_t pte)276 extern inline pte_t pte_mkwrite(pte_t pte) { pte_val(pte) &= ~_PAGE_FOW; return pte; }
pte_mkdirty(pte_t pte)277 extern inline pte_t pte_mkdirty(pte_t pte) { pte_val(pte) |= __DIRTY_BITS; return pte; }
pte_mkyoung(pte_t pte)278 extern inline pte_t pte_mkyoung(pte_t pte) { pte_val(pte) |= __ACCESS_BITS; return pte; }
pte_mkspecial(pte_t pte)279 extern inline pte_t pte_mkspecial(pte_t pte) { return pte; }
280
281 #define PAGE_DIR_OFFSET(tsk,address) pgd_offset((tsk),(address))
282
283 /* to find an entry in a kernel page-table-directory */
284 #define pgd_offset_k(address) pgd_offset(&init_mm, (address))
285
286 /* to find an entry in a page-table-directory. */
287 #define pgd_index(address) (((address) >> PGDIR_SHIFT) & (PTRS_PER_PGD-1))
288 #define pgd_offset(mm, address) ((mm)->pgd+pgd_index(address))
289
290 /*
291 * The smp_read_barrier_depends() in the following functions are required to
292 * order the load of *dir (the pointer in the top level page table) with any
293 * subsequent load of the returned pmd_t *ret (ret is data dependent on *dir).
294 *
295 * If this ordering is not enforced, the CPU might load an older value of
296 * *ret, which may be uninitialized data. See mm/memory.c:__pte_alloc for
297 * more details.
298 *
299 * Note that we never change the mm->pgd pointer after the task is running, so
300 * pgd_offset does not require such a barrier.
301 */
302
303 /* Find an entry in the second-level page table.. */
pmd_offset(pgd_t * dir,unsigned long address)304 extern inline pmd_t * pmd_offset(pgd_t * dir, unsigned long address)
305 {
306 pmd_t *ret = (pmd_t *) pgd_page_vaddr(*dir) + ((address >> PMD_SHIFT) & (PTRS_PER_PAGE - 1));
307 smp_read_barrier_depends(); /* see above */
308 return ret;
309 }
310
311 /* Find an entry in the third-level page table.. */
pte_offset_kernel(pmd_t * dir,unsigned long address)312 extern inline pte_t * pte_offset_kernel(pmd_t * dir, unsigned long address)
313 {
314 pte_t *ret = (pte_t *) pmd_page_vaddr(*dir)
315 + ((address >> PAGE_SHIFT) & (PTRS_PER_PAGE - 1));
316 smp_read_barrier_depends(); /* see above */
317 return ret;
318 }
319
320 #define pte_offset_map(dir,addr) pte_offset_kernel((dir),(addr))
321 #define pte_unmap(pte) do { } while (0)
322
323 extern pgd_t swapper_pg_dir[1024];
324
325 /*
326 * The Alpha doesn't have any external MMU info: the kernel page
327 * tables contain all the necessary information.
328 */
update_mmu_cache(struct vm_area_struct * vma,unsigned long address,pte_t * ptep)329 extern inline void update_mmu_cache(struct vm_area_struct * vma,
330 unsigned long address, pte_t *ptep)
331 {
332 }
333
334 /*
335 * Non-present pages: high 24 bits are offset, next 8 bits type,
336 * low 32 bits zero.
337 */
mk_swap_pte(unsigned long type,unsigned long offset)338 extern inline pte_t mk_swap_pte(unsigned long type, unsigned long offset)
339 { pte_t pte; pte_val(pte) = (type << 32) | (offset << 40); return pte; }
340
341 #define __swp_type(x) (((x).val >> 32) & 0xff)
342 #define __swp_offset(x) ((x).val >> 40)
343 #define __swp_entry(type, off) ((swp_entry_t) { pte_val(mk_swap_pte((type), (off))) })
344 #define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
345 #define __swp_entry_to_pte(x) ((pte_t) { (x).val })
346
347 #define pte_to_pgoff(pte) (pte_val(pte) >> 32)
348 #define pgoff_to_pte(off) ((pte_t) { ((off) << 32) | _PAGE_FILE })
349
350 #define PTE_FILE_MAX_BITS 32
351
352 #ifndef CONFIG_DISCONTIGMEM
353 #define kern_addr_valid(addr) (1)
354 #endif
355
356 #define io_remap_pfn_range(vma, start, pfn, size, prot) \
357 remap_pfn_range(vma, start, pfn, size, prot)
358
359 #define pte_ERROR(e) \
360 printk("%s:%d: bad pte %016lx.\n", __FILE__, __LINE__, pte_val(e))
361 #define pmd_ERROR(e) \
362 printk("%s:%d: bad pmd %016lx.\n", __FILE__, __LINE__, pmd_val(e))
363 #define pgd_ERROR(e) \
364 printk("%s:%d: bad pgd %016lx.\n", __FILE__, __LINE__, pgd_val(e))
365
366 extern void paging_init(void);
367
368 #include <asm-generic/pgtable.h>
369
370 /*
371 * No page table caches to initialise
372 */
373 #define pgtable_cache_init() do { } while (0)
374
375 /* We have our own get_unmapped_area to cope with ADDR_LIMIT_32BIT. */
376 #define HAVE_ARCH_UNMAPPED_AREA
377
378 #endif /* _ALPHA_PGTABLE_H */
379