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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/config.h>
14#include <linux/mmzone.h>
15
16#include <asm/page.h>
17#include <asm/processor.h> /* For TASK_SIZE */
18#include <asm/machvec.h>
19
20/* Certain architectures need to do special things when PTEs
21 * within a page table are directly modified. Thus, the following
22 * hook is made available.
23 */
24#define set_pte(pteptr, pteval) ((*(pteptr)) = (pteval))
25#define set_pte_at(mm,addr,ptep,pteval) set_pte(ptep,pteval)
26
27/* PMD_SHIFT determines the size of the area a second-level page table can map */
28#define PMD_SHIFT (PAGE_SHIFT + (PAGE_SHIFT-3))
29#define PMD_SIZE (1UL << PMD_SHIFT)
30#define PMD_MASK (~(PMD_SIZE-1))
31
32/* PGDIR_SHIFT determines what a third-level page table entry can map */
33#define PGDIR_SHIFT (PAGE_SHIFT + 2*(PAGE_SHIFT-3))
34#define PGDIR_SIZE (1UL << PGDIR_SHIFT)
35#define PGDIR_MASK (~(PGDIR_SIZE-1))
36
37/*
38 * Entries per page directory level: the Alpha is three-level, with
39 * all levels having a one-page page table.
40 */
41#define PTRS_PER_PTE (1UL << (PAGE_SHIFT-3))
42#define PTRS_PER_PMD (1UL << (PAGE_SHIFT-3))
43#define PTRS_PER_PGD (1UL << (PAGE_SHIFT-3))
44#define USER_PTRS_PER_PGD (TASK_SIZE / PGDIR_SIZE)
45#define FIRST_USER_ADDRESS 0
46
47/* Number of pointers that fit on a page: this will go away. */
48#define PTRS_PER_PAGE (1UL << (PAGE_SHIFT-3))
49
50#ifdef CONFIG_ALPHA_LARGE_VMALLOC
51#define VMALLOC_START 0xfffffe0000000000
52#else
53#define VMALLOC_START (-2*PGDIR_SIZE)
54#endif
55#define VMALLOC_END (-PGDIR_SIZE)
56
57/*
58 * OSF/1 PAL-code-imposed page table bits
59 */
60#define _PAGE_VALID 0x0001
61#define _PAGE_FOR 0x0002 /* used for page protection (fault on read) */
62#define _PAGE_FOW 0x0004 /* used for page protection (fault on write) */
63#define _PAGE_FOE 0x0008 /* used for page protection (fault on exec) */
64#define _PAGE_ASM 0x0010
65#define _PAGE_KRE 0x0100 /* xxx - see below on the "accessed" bit */
66#define _PAGE_URE 0x0200 /* xxx */
67#define _PAGE_KWE 0x1000 /* used to do the dirty bit in software */
68#define _PAGE_UWE 0x2000 /* used to do the dirty bit in software */
69
70/* .. and these are ours ... */
71#define _PAGE_DIRTY 0x20000
72#define _PAGE_ACCESSED 0x40000
73#define _PAGE_FILE 0x80000 /* set:pagecache, unset:swap */
74
75/*
76 * NOTE! The "accessed" bit isn't necessarily exact: it can be kept exactly
77 * by software (use the KRE/URE/KWE/UWE bits appropriately), but I'll fake it.
78 * Under Linux/AXP, the "accessed" bit just means "read", and I'll just use
79 * the KRE/URE bits to watch for it. That way we don't need to overload the
80 * KWE/UWE bits with both handling dirty and accessed.
81 *
82 * Note that the kernel uses the accessed bit just to check whether to page
83 * out a page or not, so it doesn't have to be exact anyway.
84 */
85
86#define __DIRTY_BITS (_PAGE_DIRTY | _PAGE_KWE | _PAGE_UWE)
87#define __ACCESS_BITS (_PAGE_ACCESSED | _PAGE_KRE | _PAGE_URE)
88
89#define _PFN_MASK 0xFFFFFFFF00000000UL
90
91#define _PAGE_TABLE (_PAGE_VALID | __DIRTY_BITS | __ACCESS_BITS)
92#define _PAGE_CHG_MASK (_PFN_MASK | __DIRTY_BITS | __ACCESS_BITS)
93
94/*
95 * All the normal masks have the "page accessed" bits on, as any time they are used,
96 * the page is accessed. They are cleared only by the page-out routines
97 */
98#define PAGE_NONE __pgprot(_PAGE_VALID | __ACCESS_BITS | _PAGE_FOR | _PAGE_FOW | _PAGE_FOE)
99#define PAGE_SHARED __pgprot(_PAGE_VALID | __ACCESS_BITS)
100#define PAGE_COPY __pgprot(_PAGE_VALID | __ACCESS_BITS | _PAGE_FOW)
101#define PAGE_READONLY __pgprot(_PAGE_VALID | __ACCESS_BITS | _PAGE_FOW)
102#define PAGE_KERNEL __pgprot(_PAGE_VALID | _PAGE_ASM | _PAGE_KRE | _PAGE_KWE)
103
104#define _PAGE_NORMAL(x) __pgprot(_PAGE_VALID | __ACCESS_BITS | (x))
105
106#define _PAGE_P(x) _PAGE_NORMAL((x) | (((x) & _PAGE_FOW)?0:_PAGE_FOW))
107#define _PAGE_S(x) _PAGE_NORMAL(x)
108
109/*
110 * The hardware can handle write-only mappings, but as the Alpha
111 * architecture does byte-wide writes with a read-modify-write
112 * sequence, it's not practical to have write-without-read privs.
113 * Thus the "-w- -> rw-" and "-wx -> rwx" mapping here (and in
114 * arch/alpha/mm/fault.c)
115 */
116 /* xwr */
117#define __P000 _PAGE_P(_PAGE_FOE | _PAGE_FOW | _PAGE_FOR)
118#define __P001 _PAGE_P(_PAGE_FOE | _PAGE_FOW)
119#define __P010 _PAGE_P(_PAGE_FOE)
120#define __P011 _PAGE_P(_PAGE_FOE)
121#define __P100 _PAGE_P(_PAGE_FOW | _PAGE_FOR)
122#define __P101 _PAGE_P(_PAGE_FOW)
123#define __P110 _PAGE_P(0)
124#define __P111 _PAGE_P(0)
125
126#define __S000 _PAGE_S(_PAGE_FOE | _PAGE_FOW | _PAGE_FOR)
127#define __S001 _PAGE_S(_PAGE_FOE | _PAGE_FOW)
128#define __S010 _PAGE_S(_PAGE_FOE)
129#define __S011 _PAGE_S(_PAGE_FOE)
130#define __S100 _PAGE_S(_PAGE_FOW | _PAGE_FOR)
131#define __S101 _PAGE_S(_PAGE_FOW)
132#define __S110 _PAGE_S(0)
133#define __S111 _PAGE_S(0)
134
135/*
136 * pgprot_noncached() is only for infiniband pci support, and a real
137 * implementation for RAM would be more complicated.
138 */
139#define pgprot_noncached(prot) (prot)
140
141/*
142 * BAD_PAGETABLE is used when we need a bogus page-table, while
143 * BAD_PAGE is used for a bogus page.
144 *
145 * ZERO_PAGE is a global shared page that is always zero: used
146 * for zero-mapped memory areas etc..
147 */
148extern pte_t __bad_page(void);
149extern pmd_t * __bad_pagetable(void);
150
151extern unsigned long __zero_page(void);
152
153#define BAD_PAGETABLE __bad_pagetable()
154#define BAD_PAGE __bad_page()
155#define ZERO_PAGE(vaddr) (virt_to_page(ZERO_PGE))
156
157/* number of bits that fit into a memory pointer */
158#define BITS_PER_PTR (8*sizeof(unsigned long))
159
160/* to align the pointer to a pointer address */
161#define PTR_MASK (~(sizeof(void*)-1))
162
163/* sizeof(void*)==1<<SIZEOF_PTR_LOG2 */
164#define SIZEOF_PTR_LOG2 3
165
166/* to find an entry in a page-table */
167#define PAGE_PTR(address) \
168 ((unsigned long)(address)>>(PAGE_SHIFT-SIZEOF_PTR_LOG2)&PTR_MASK&~PAGE_MASK)
169
170/*
171 * On certain platforms whose physical address space can overlap KSEG,
172 * namely EV6 and above, we must re-twiddle the physaddr to restore the
173 * correct high-order bits.
174 *
175 * This is extremely confusing until you realize that this is actually
176 * just working around a userspace bug. The X server was intending to
177 * provide the physical address but instead provided the KSEG address.
178 * Or tried to, except it's not representable.
179 *
180 * On Tsunami there's nothing meaningful at 0x40000000000, so this is
181 * a safe thing to do. Come the first core logic that does put something
182 * in this area -- memory or whathaveyou -- then this hack will have
183 * to go away. So be prepared!
184 */
185
186#if defined(CONFIG_ALPHA_GENERIC) && defined(USE_48_BIT_KSEG)
187#error "EV6-only feature in a generic kernel"
188#endif
189#if defined(CONFIG_ALPHA_GENERIC) || \
190 (defined(CONFIG_ALPHA_EV6) && !defined(USE_48_BIT_KSEG))
191#define KSEG_PFN (0xc0000000000UL >> PAGE_SHIFT)
192#define PHYS_TWIDDLE(pfn) \
193 ((((pfn) & KSEG_PFN) == (0x40000000000UL >> PAGE_SHIFT)) \
194 ? ((pfn) ^= KSEG_PFN) : (pfn))
195#else
196#define PHYS_TWIDDLE(pfn) (pfn)
197#endif
198
199/*
200 * Conversion functions: convert a page and protection to a page entry,
201 * and a page entry and page directory to the page they refer to.
202 */
203#ifndef CONFIG_DISCONTIGMEM
204#define page_to_pa(page) (((page) - mem_map) << PAGE_SHIFT)
205
206#define pte_pfn(pte) (pte_val(pte) >> 32)
207#define pte_page(pte) pfn_to_page(pte_pfn(pte))
208#define mk_pte(page, pgprot) \
209({ \
210 pte_t pte; \
211 \
212 pte_val(pte) = (page_to_pfn(page) << 32) | pgprot_val(pgprot); \
213 pte; \
214})
215#endif
216
217extern inline pte_t pfn_pte(unsigned long physpfn, pgprot_t pgprot)
218{ pte_t pte; pte_val(pte) = (PHYS_TWIDDLE(physpfn) << 32) | pgprot_val(pgprot); return pte; }
219
220extern inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
221{ pte_val(pte) = (pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot); return pte; }
222
223extern inline void pmd_set(pmd_t * pmdp, pte_t * ptep)
224{ pmd_val(*pmdp) = _PAGE_TABLE | ((((unsigned long) ptep) - PAGE_OFFSET) << (32-PAGE_SHIFT)); }
225
226extern inline void pgd_set(pgd_t * pgdp, pmd_t * pmdp)
227{ pgd_val(*pgdp) = _PAGE_TABLE | ((((unsigned long) pmdp) - PAGE_OFFSET) << (32-PAGE_SHIFT)); }
228
229
230extern inline unsigned long
231pmd_page_kernel(pmd_t pmd)
232{
233 return ((pmd_val(pmd) & _PFN_MASK) >> (32-PAGE_SHIFT)) + PAGE_OFFSET;
234}
235
236#ifndef CONFIG_DISCONTIGMEM
237#define pmd_page(pmd) (mem_map + ((pmd_val(pmd) & _PFN_MASK) >> 32))
238#endif
239
240extern inline unsigned long pgd_page(pgd_t pgd)
241{ return PAGE_OFFSET + ((pgd_val(pgd) & _PFN_MASK) >> (32-PAGE_SHIFT)); }
242
243extern inline int pte_none(pte_t pte) { return !pte_val(pte); }
244extern inline int pte_present(pte_t pte) { return pte_val(pte) & _PAGE_VALID; }
245extern inline void pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
246{
247 pte_val(*ptep) = 0;
248}
249
250extern inline int pmd_none(pmd_t pmd) { return !pmd_val(pmd); }
251extern inline int pmd_bad(pmd_t pmd) { return (pmd_val(pmd) & ~_PFN_MASK) != _PAGE_TABLE; }
252extern inline int pmd_present(pmd_t pmd) { return pmd_val(pmd) & _PAGE_VALID; }
253extern inline void pmd_clear(pmd_t * pmdp) { pmd_val(*pmdp) = 0; }
254
255extern inline int pgd_none(pgd_t pgd) { return !pgd_val(pgd); }
256extern inline int pgd_bad(pgd_t pgd) { return (pgd_val(pgd) & ~_PFN_MASK) != _PAGE_TABLE; }
257extern inline int pgd_present(pgd_t pgd) { return pgd_val(pgd) & _PAGE_VALID; }
258extern inline void pgd_clear(pgd_t * pgdp) { pgd_val(*pgdp) = 0; }
259
260/*
261 * The following only work if pte_present() is true.
262 * Undefined behaviour if not..
263 */
264extern inline int pte_read(pte_t pte) { return !(pte_val(pte) & _PAGE_FOR); }
265extern inline int pte_write(pte_t pte) { return !(pte_val(pte) & _PAGE_FOW); }
266extern inline int pte_exec(pte_t pte) { return !(pte_val(pte) & _PAGE_FOE); }
267extern inline int pte_dirty(pte_t pte) { return pte_val(pte) & _PAGE_DIRTY; }
268extern inline int pte_young(pte_t pte) { return pte_val(pte) & _PAGE_ACCESSED; }
269extern inline int pte_file(pte_t pte) { return pte_val(pte) & _PAGE_FILE; }
270
271extern inline pte_t pte_wrprotect(pte_t pte) { pte_val(pte) |= _PAGE_FOW; return pte; }
272extern inline pte_t pte_rdprotect(pte_t pte) { pte_val(pte) |= _PAGE_FOR; return pte; }
273extern inline pte_t pte_exprotect(pte_t pte) { pte_val(pte) |= _PAGE_FOE; return pte; }
274extern inline pte_t pte_mkclean(pte_t pte) { pte_val(pte) &= ~(__DIRTY_BITS); return pte; }
275extern inline pte_t pte_mkold(pte_t pte) { pte_val(pte) &= ~(__ACCESS_BITS); return pte; }
276extern inline pte_t pte_mkwrite(pte_t pte) { pte_val(pte) &= ~_PAGE_FOW; return pte; }
277extern inline pte_t pte_mkread(pte_t pte) { pte_val(pte) &= ~_PAGE_FOR; return pte; }
278extern inline pte_t pte_mkexec(pte_t pte) { pte_val(pte) &= ~_PAGE_FOE; return pte; }
279extern inline pte_t pte_mkdirty(pte_t pte) { pte_val(pte) |= __DIRTY_BITS; return pte; }
280extern inline pte_t pte_mkyoung(pte_t pte) { pte_val(pte) |= __ACCESS_BITS; return pte; }
281
282#define PAGE_DIR_OFFSET(tsk,address) pgd_offset((tsk),(address))
283
284/* to find an entry in a kernel page-table-directory */
285#define pgd_offset_k(address) pgd_offset(&init_mm, (address))
286
287/* to find an entry in a page-table-directory. */
288#define pgd_index(address) (((address) >> PGDIR_SHIFT) & (PTRS_PER_PGD-1))
289#define pgd_offset(mm, address) ((mm)->pgd+pgd_index(address))
290
291/* Find an entry in the second-level page table.. */
292extern inline pmd_t * pmd_offset(pgd_t * dir, unsigned long address)
293{
294 return (pmd_t *) pgd_page(*dir) + ((address >> PMD_SHIFT) & (PTRS_PER_PAGE - 1));
295}
296
297/* Find an entry in the third-level page table.. */
298extern inline pte_t * pte_offset_kernel(pmd_t * dir, unsigned long address)
299{
300 return (pte_t *) pmd_page_kernel(*dir)
301 + ((address >> PAGE_SHIFT) & (PTRS_PER_PAGE - 1));
302}
303
304#define pte_offset_map(dir,addr) pte_offset_kernel((dir),(addr))
305#define pte_offset_map_nested(dir,addr) pte_offset_kernel((dir),(addr))
306#define pte_unmap(pte) do { } while (0)
307#define pte_unmap_nested(pte) do { } while (0)
308
309extern pgd_t swapper_pg_dir[1024];
310
311/*
312 * The Alpha doesn't have any external MMU info: the kernel page
313 * tables contain all the necessary information.
314 */
315extern inline void update_mmu_cache(struct vm_area_struct * vma,
316 unsigned long address, pte_t pte)
317{
318}
319
320/*
321 * Non-present pages: high 24 bits are offset, next 8 bits type,
322 * low 32 bits zero.
323 */
324extern inline pte_t mk_swap_pte(unsigned long type, unsigned long offset)
325{ pte_t pte; pte_val(pte) = (type << 32) | (offset << 40); return pte; }
326
327#define __swp_type(x) (((x).val >> 32) & 0xff)
328#define __swp_offset(x) ((x).val >> 40)
329#define __swp_entry(type, off) ((swp_entry_t) { pte_val(mk_swap_pte((type), (off))) })
330#define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
331#define __swp_entry_to_pte(x) ((pte_t) { (x).val })
332
333#define pte_to_pgoff(pte) (pte_val(pte) >> 32)
334#define pgoff_to_pte(off) ((pte_t) { ((off) << 32) | _PAGE_FILE })
335
336#define PTE_FILE_MAX_BITS 32
337
338#ifndef CONFIG_DISCONTIGMEM
339#define kern_addr_valid(addr) (1)
340#endif
341
342#define io_remap_pfn_range(vma, start, pfn, size, prot) \
343 remap_pfn_range(vma, start, pfn, size, prot)
344
345#define MK_IOSPACE_PFN(space, pfn) (pfn)
346#define GET_IOSPACE(pfn) 0
347#define GET_PFN(pfn) (pfn)
348
349#define pte_ERROR(e) \
350 printk("%s:%d: bad pte %016lx.\n", __FILE__, __LINE__, pte_val(e))
351#define pmd_ERROR(e) \
352 printk("%s:%d: bad pmd %016lx.\n", __FILE__, __LINE__, pmd_val(e))
353#define pgd_ERROR(e) \
354 printk("%s:%d: bad pgd %016lx.\n", __FILE__, __LINE__, pgd_val(e))
355
356extern void paging_init(void);
357
358#include <asm-generic/pgtable.h>
359
360/*
361 * No page table caches to initialise
362 */
363#define pgtable_cache_init() do { } while (0)
364
365/* We have our own get_unmapped_area to cope with ADDR_LIMIT_32BIT. */
366#define HAVE_ARCH_UNMAPPED_AREA
367
368#endif /* _ALPHA_PGTABLE_H */