aboutsummaryrefslogtreecommitdiffstats
path: root/include/asm-alpha/pgtable.h
blob: 99037b0323570c1e4831e1ec2228bc455fcabef0 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
#ifndef _ALPHA_PGTABLE_H
#define _ALPHA_PGTABLE_H

#include <asm-generic/4level-fixup.h>

/*
 * This file contains the functions and defines necessary to modify and use
 * the Alpha page table tree.
 *
 * This hopefully works with any standard Alpha page-size, as defined
 * in <asm/page.h> (currently 8192).
 */
#include <linux/mmzone.h>

#include <asm/page.h>
#include <asm/processor.h>	/* For TASK_SIZE */
#include <asm/machvec.h>

struct mm_struct;
struct vm_area_struct;

/* Certain architectures need to do special things when PTEs
 * within a page table are directly modified.  Thus, the following
 * hook is made available.
 */
#define set_pte(pteptr, pteval) ((*(pteptr)) = (pteval))
#define set_pte_at(mm,addr,ptep,pteval) set_pte(ptep,pteval)

/* PMD_SHIFT determines the size of the area a second-level page table can map */
#define PMD_SHIFT	(PAGE_SHIFT + (PAGE_SHIFT-3))
#define PMD_SIZE	(1UL << PMD_SHIFT)
#define PMD_MASK	(~(PMD_SIZE-1))

/* PGDIR_SHIFT determines what a third-level page table entry can map */
#define PGDIR_SHIFT	(PAGE_SHIFT + 2*(PAGE_SHIFT-3))
#define PGDIR_SIZE	(1UL << PGDIR_SHIFT)
#define PGDIR_MASK	(~(PGDIR_SIZE-1))

/*
 * Entries per page directory level:  the Alpha is three-level, with
 * all levels having a one-page page table.
 */
#define PTRS_PER_PTE	(1UL << (PAGE_SHIFT-3))
#define PTRS_PER_PMD	(1UL << (PAGE_SHIFT-3))
#define PTRS_PER_PGD	(1UL << (PAGE_SHIFT-3))
#define USER_PTRS_PER_PGD	(TASK_SIZE / PGDIR_SIZE)
#define FIRST_USER_ADDRESS	0

/* Number of pointers that fit on a page:  this will go away. */
#define PTRS_PER_PAGE	(1UL << (PAGE_SHIFT-3))

#ifdef CONFIG_ALPHA_LARGE_VMALLOC
#define VMALLOC_START		0xfffffe0000000000
#else
#define VMALLOC_START		(-2*PGDIR_SIZE)
#endif
#define VMALLOC_END		(-PGDIR_SIZE)

/*
 * OSF/1 PAL-code-imposed page table bits
 */
#define _PAGE_VALID	0x0001
#define _PAGE_FOR	0x0002	/* used for page protection (fault on read) */
#define _PAGE_FOW	0x0004	/* used for page protection (fault on write) */
#define _PAGE_FOE	0x0008	/* used for page protection (fault on exec) */
#define _PAGE_ASM	0x0010
#define _PAGE_KRE	0x0100	/* xxx - see below on the "accessed" bit */
#define _PAGE_URE	0x0200	/* xxx */
#define _PAGE_KWE	0x1000	/* used to do the dirty bit in software */
#define _PAGE_UWE	0x2000	/* used to do the dirty bit in software */

/* .. and these are ours ... */
#define _PAGE_DIRTY	0x20000
#define _PAGE_ACCESSED	0x40000
#define _PAGE_FILE	0x80000	/* set:pagecache, unset:swap */

/*
 * NOTE! The "accessed" bit isn't necessarily exact:  it can be kept exactly
 * by software (use the KRE/URE/KWE/UWE bits appropriately), but I'll fake it.
 * Under Linux/AXP, the "accessed" bit just means "read", and I'll just use
 * the KRE/URE bits to watch for it. That way we don't need to overload the
 * KWE/UWE bits with both handling dirty and accessed.
 *
 * Note that the kernel uses the accessed bit just to check whether to page
 * out a page or not, so it doesn't have to be exact anyway.
 */

#define __DIRTY_BITS	(_PAGE_DIRTY | _PAGE_KWE | _PAGE_UWE)
#define __ACCESS_BITS	(_PAGE_ACCESSED | _PAGE_KRE | _PAGE_URE)

#define _PFN_MASK	0xFFFFFFFF00000000UL

#define _PAGE_TABLE	(_PAGE_VALID | __DIRTY_BITS | __ACCESS_BITS)
#define _PAGE_CHG_MASK	(_PFN_MASK | __DIRTY_BITS | __ACCESS_BITS)

/*
 * All the normal masks have the "page accessed" bits on, as any time they are used,
 * the page is accessed. They are cleared only by the page-out routines
 */
#define PAGE_NONE	__pgprot(_PAGE_VALID | __ACCESS_BITS | _PAGE_FOR | _PAGE_FOW | _PAGE_FOE)
#define PAGE_SHARED	__pgprot(_PAGE_VALID | __ACCESS_BITS)
#define PAGE_COPY	__pgprot(_PAGE_VALID | __ACCESS_BITS | _PAGE_FOW)
#define PAGE_READONLY	__pgprot(_PAGE_VALID | __ACCESS_BITS | _PAGE_FOW)
#define PAGE_KERNEL	__pgprot(_PAGE_VALID | _PAGE_ASM | _PAGE_KRE | _PAGE_KWE)

#define _PAGE_NORMAL(x) __pgprot(_PAGE_VALID | __ACCESS_BITS | (x))

#define _PAGE_P(x) _PAGE_NORMAL((x) | (((x) & _PAGE_FOW)?0:_PAGE_FOW))
#define _PAGE_S(x) _PAGE_NORMAL(x)

/*
 * The hardware can handle write-only mappings, but as the Alpha
 * architecture does byte-wide writes with a read-modify-write
 * sequence, it's not practical to have write-without-read privs.
 * Thus the "-w- -> rw-" and "-wx -> rwx" mapping here (and in
 * arch/alpha/mm/fault.c)
 */
	/* xwr */
#define __P000	_PAGE_P(_PAGE_FOE | _PAGE_FOW | _PAGE_FOR)
#define __P001	_PAGE_P(_PAGE_FOE | _PAGE_FOW)
#define __P010	_PAGE_P(_PAGE_FOE)
#define __P011	_PAGE_P(_PAGE_FOE)
#define __P100	_PAGE_P(_PAGE_FOW | _PAGE_FOR)
#define __P101	_PAGE_P(_PAGE_FOW)
#define __P110	_PAGE_P(0)
#define __P111	_PAGE_P(0)

#define __S000	_PAGE_S(_PAGE_FOE | _PAGE_FOW | _PAGE_FOR)
#define __S001	_PAGE_S(_PAGE_FOE | _PAGE_FOW)
#define __S010	_PAGE_S(_PAGE_FOE)
#define __S011	_PAGE_S(_PAGE_FOE)
#define __S100	_PAGE_S(_PAGE_FOW | _PAGE_FOR)
#define __S101	_PAGE_S(_PAGE_FOW)
#define __S110	_PAGE_S(0)
#define __S111	_PAGE_S(0)

/*
 * pgprot_noncached() is only for infiniband pci support, and a real
 * implementation for RAM would be more complicated.
 */
#define pgprot_noncached(prot)	(prot)

/*
 * BAD_PAGETABLE is used when we need a bogus page-table, while
 * BAD_PAGE is used for a bogus page.
 *
 * ZERO_PAGE is a global shared page that is always zero:  used
 * for zero-mapped memory areas etc..
 */
extern pte_t __bad_page(void);
extern pmd_t * __bad_pagetable(void);

extern unsigned long __zero_page(void);

#define BAD_PAGETABLE	__bad_pagetable()
#define BAD_PAGE	__bad_page()
#define ZERO_PAGE(vaddr)	(virt_to_page(ZERO_PGE))

/* number of bits that fit into a memory pointer */
#define BITS_PER_PTR			(8*sizeof(unsigned long))

/* to align the pointer to a pointer address */
#define PTR_MASK			(~(sizeof(void*)-1))

/* sizeof(void*)==1<<SIZEOF_PTR_LOG2 */
#define SIZEOF_PTR_LOG2			3

/* to find an entry in a page-table */
#define PAGE_PTR(address)		\
  ((unsigned long)(address)>>(PAGE_SHIFT-SIZEOF_PTR_LOG2)&PTR_MASK&~PAGE_MASK)

/*
 * On certain platforms whose physical address space can overlap KSEG,
 * namely EV6 and above, we must re-twiddle the physaddr to restore the
 * correct high-order bits.
 *
 * This is extremely confusing until you realize that this is actually
 * just working around a userspace bug.  The X server was intending to
 * provide the physical address but instead provided the KSEG address.
 * Or tried to, except it's not representable.
 * 
 * On Tsunami there's nothing meaningful at 0x40000000000, so this is
 * a safe thing to do.  Come the first core logic that does put something
 * in this area -- memory or whathaveyou -- then this hack will have
 * to go away.  So be prepared!
 */

#if defined(CONFIG_ALPHA_GENERIC) && defined(USE_48_BIT_KSEG)
#error "EV6-only feature in a generic kernel"
#endif
#if defined(CONFIG_ALPHA_GENERIC) || \
    (defined(CONFIG_ALPHA_EV6) && !defined(USE_48_BIT_KSEG))
#define KSEG_PFN	(0xc0000000000UL >> PAGE_SHIFT)
#define PHYS_TWIDDLE(pfn) \
  ((((pfn) & KSEG_PFN) == (0x40000000000UL >> PAGE_SHIFT)) \
  ? ((pfn) ^= KSEG_PFN) : (pfn))
#else
#define PHYS_TWIDDLE(pfn) (pfn)
#endif

/*
 * Conversion functions:  convert a page and protection to a page entry,
 * and a page entry and page directory to the page they refer to.
 */
#ifndef CONFIG_DISCONTIGMEM
#define page_to_pa(page)	(((page) - mem_map) << PAGE_SHIFT)

#define pte_pfn(pte)	(pte_val(pte) >> 32)
#define pte_page(pte)	pfn_to_page(pte_pfn(pte))
#define mk_pte(page, pgprot)						\
({									\
	pte_t pte;							\
									\
	pte_val(pte) = (page_to_pfn(page) << 32) | pgprot_val(pgprot);	\
	pte;								\
})
#endif

extern inline pte_t pfn_pte(unsigned long physpfn, pgprot_t pgprot)
{ pte_t pte; pte_val(pte) = (PHYS_TWIDDLE(physpfn) << 32) | pgprot_val(pgprot); return pte; }

extern inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
{ pte_val(pte) = (pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot); return pte; }

extern inline void pmd_set(pmd_t * pmdp, pte_t * ptep)
{ pmd_val(*pmdp) = _PAGE_TABLE | ((((unsigned long) ptep) - PAGE_OFFSET) << (32-PAGE_SHIFT)); }

extern inline void pgd_set(pgd_t * pgdp, pmd_t * pmdp)
{ pgd_val(*pgdp) = _PAGE_TABLE | ((((unsigned long) pmdp) - PAGE_OFFSET) << (32-PAGE_SHIFT)); }


extern inline unsigned long
pmd_page_vaddr(pmd_t pmd)
{
	return ((pmd_val(pmd) & _PFN_MASK) >> (32-PAGE_SHIFT)) + PAGE_OFFSET;
}

#ifndef CONFIG_DISCONTIGMEM
#define pmd_page(pmd)	(mem_map + ((pmd_val(pmd) & _PFN_MASK) >> 32))
#define pgd_page(pgd)	(mem_map + ((pgd_val(pgd) & _PFN_MASK) >> 32))
#endif

extern inline unsigned long pgd_page_vaddr(pgd_t pgd)
{ return PAGE_OFFSET + ((pgd_val(pgd) & _PFN_MASK) >> (32-PAGE_SHIFT)); }

extern inline int pte_none(pte_t pte)		{ return !pte_val(pte); }
extern inline int pte_present(pte_t pte)	{ return pte_val(pte) & _PAGE_VALID; }
extern inline void pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
{
	pte_val(*ptep) = 0;
}

extern inline int pmd_none(pmd_t pmd)		{ return !pmd_val(pmd); }
extern inline int pmd_bad(pmd_t pmd)		{ return (pmd_val(pmd) & ~_PFN_MASK) != _PAGE_TABLE; }
extern inline int pmd_present(pmd_t pmd)	{ return pmd_val(pmd) & _PAGE_VALID; }
extern inline void pmd_clear(pmd_t * pmdp)	{ pmd_val(*pmdp) = 0; }

extern inline int pgd_none(pgd_t pgd)		{ return !pgd_val(pgd); }
extern inline int pgd_bad(pgd_t pgd)		{ return (pgd_val(pgd) & ~_PFN_MASK) != _PAGE_TABLE; }
extern inline int pgd_present(pgd_t pgd)	{ return pgd_val(pgd) & _PAGE_VALID; }
extern inline void pgd_clear(pgd_t * pgdp)	{ pgd_val(*pgdp) = 0; }

/*
 * The following only work if pte_present() is true.
 * Undefined behaviour if not..
 */
extern inline int pte_write(pte_t pte)		{ return !(pte_val(pte) & _PAGE_FOW); }
extern inline int pte_dirty(pte_t pte)		{ return pte_val(pte) & _PAGE_DIRTY; }
extern inline int pte_young(pte_t pte)		{ return pte_val(pte) & _PAGE_ACCESSED; }
extern inline int pte_file(pte_t pte)		{ return pte_val(pte) & _PAGE_FILE; }

extern inline pte_t pte_wrprotect(pte_t pte)	{ pte_val(pte) |= _PAGE_FOW; return pte; }
extern inline pte_t pte_mkclean(pte_t pte)	{ pte_val(pte) &= ~(__DIRTY_BITS); return pte; }
extern inline pte_t pte_mkold(pte_t pte)	{ pte_val(pte) &= ~(__ACCESS_BITS); return pte; }
extern inline pte_t pte_mkwrite(pte_t pte)	{ pte_val(pte) &= ~_PAGE_FOW; return pte; }
extern inline pte_t pte_mkdirty(pte_t pte)	{ pte_val(pte) |= __DIRTY_BITS; return pte; }
extern inline pte_t pte_mkyoung(pte_t pte)	{ pte_val(pte) |= __ACCESS_BITS; return pte; }

#define PAGE_DIR_OFFSET(tsk,address) pgd_offset((tsk),(address))

/* to find an entry in a kernel page-table-directory */
#define pgd_offset_k(address) pgd_offset(&init_mm, (address))

/* to find an entry in a page-table-directory. */
#define pgd_index(address)	(((address) >> PGDIR_SHIFT) & (PTRS_PER_PGD-1))
#define pgd_offset(mm, address)	((mm)->pgd+pgd_index(address))

/* Find an entry in the second-level page table.. */
extern inline pmd_t * pmd_offset(pgd_t * dir, unsigned long address)
{
	return (pmd_t *) pgd_page_vaddr(*dir) + ((address >> PMD_SHIFT) & (PTRS_PER_PAGE - 1));
}

/* Find an entry in the third-level page table.. */
extern inline pte_t * pte_offset_kernel(pmd_t * dir, unsigned long address)
{
	return (pte_t *) pmd_page_vaddr(*dir)
		+ ((address >> PAGE_SHIFT) & (PTRS_PER_PAGE - 1));
}

#define pte_offset_map(dir,addr)	pte_offset_kernel((dir),(addr))
#define pte_offset_map_nested(dir,addr)	pte_offset_kernel((dir),(addr))
#define pte_unmap(pte)			do { } while (0)
#define pte_unmap_nested(pte)		do { } while (0)

extern pgd_t swapper_pg_dir[1024];

/*
 * The Alpha doesn't have any external MMU info:  the kernel page
 * tables contain all the necessary information.
 */
extern inline void update_mmu_cache(struct vm_area_struct * vma,
	unsigned long address, pte_t pte)
{
}

/*
 * Non-present pages:  high 24 bits are offset, next 8 bits type,
 * low 32 bits zero.
 */
extern inline pte_t mk_swap_pte(unsigned long type, unsigned long offset)
{ pte_t pte; pte_val(pte) = (type << 32) | (offset << 40); return pte; }

#define __swp_type(x)		(((x).val >> 32) & 0xff)
#define __swp_offset(x)		((x).val >> 40)
#define __swp_entry(type, off)	((swp_entry_t) { pte_val(mk_swap_pte((type), (off))) })
#define __pte_to_swp_entry(pte)	((swp_entry_t) { pte_val(pte) })
#define __swp_entry_to_pte(x)	((pte_t) { (x).val })

#define pte_to_pgoff(pte)	(pte_val(pte) >> 32)
#define pgoff_to_pte(off)	((pte_t) { ((off) << 32) | _PAGE_FILE })

#define PTE_FILE_MAX_BITS	32

#ifndef CONFIG_DISCONTIGMEM
#define kern_addr_valid(addr)	(1)
#endif

#define io_remap_pfn_range(vma, start, pfn, size, prot)	\
		remap_pfn_range(vma, start, pfn, size, prot)

#define pte_ERROR(e) \
	printk("%s:%d: bad pte %016lx.\n", __FILE__, __LINE__, pte_val(e))
#define pmd_ERROR(e) \
	printk("%s:%d: bad pmd %016lx.\n", __FILE__, __LINE__, pmd_val(e))
#define pgd_ERROR(e) \
	printk("%s:%d: bad pgd %016lx.\n", __FILE__, __LINE__, pgd_val(e))

extern void paging_init(void);

#include <asm-generic/pgtable.h>

/*
 * No page table caches to initialise
 */
#define pgtable_cache_init()	do { } while (0)

/* We have our own get_unmapped_area to cope with ADDR_LIMIT_32BIT.  */
#define HAVE_ARCH_UNMAPPED_AREA

#endif /* _ALPHA_PGTABLE_H */