summaryrefslogtreecommitdiff
path: root/include/asm-arm26/pgtable.h
blob: af0b8907dc143af8b48fcbab175e5cef61686a1e (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
/*
 *  linux/include/asm-arm26/pgtable.h
 *
 *  Copyright (C) 2000-2002 Russell King
 *  Copyright (C) 2003 Ian Molton
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#ifndef _ASMARM_PGTABLE_H
#define _ASMARM_PGTABLE_H

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

#include <linux/config.h>
#include <asm/memory.h>

/*
 * The table below defines the page protection levels that we insert into our
 * Linux page table version.  These get translated into the best that the
 * architecture can perform.  Note that on most ARM hardware:
 *  1) We cannot do execute protection
 *  2) If we could do execute protection, then read is implied
 *  3) write implies read permissions
 */
#define __P000  PAGE_NONE
#define __P001  PAGE_READONLY
#define __P010  PAGE_COPY
#define __P011  PAGE_COPY
#define __P100  PAGE_READONLY
#define __P101  PAGE_READONLY
#define __P110  PAGE_COPY
#define __P111  PAGE_COPY

#define __S000  PAGE_NONE
#define __S001  PAGE_READONLY
#define __S010  PAGE_SHARED
#define __S011  PAGE_SHARED
#define __S100  PAGE_READONLY
#define __S101  PAGE_READONLY
#define __S110  PAGE_SHARED
#define __S111  PAGE_SHARED

/*
 * PMD_SHIFT determines the size of the area a second-level page table can map
 * PGDIR_SHIFT determines what a third-level page table entry can map
 */
#define PGD_SHIFT		25
#define PMD_SHIFT		20

#define PGD_SIZE                (1UL << PGD_SHIFT)
#define PGD_MASK                (~(PGD_SIZE-1))
#define PMD_SIZE                (1UL << PMD_SHIFT)
#define PMD_MASK                (~(PMD_SIZE-1))

/* The kernel likes to use these names for the above (ick) */
#define PGDIR_SIZE PGD_SIZE
#define PGDIR_MASK PGD_MASK

#define PTRS_PER_PGD            32
#define PTRS_PER_PMD            1
#define PTRS_PER_PTE            32

#define FIRST_USER_PGD_NR       1
#define USER_PTRS_PER_PGD       ((TASK_SIZE/PGD_SIZE) - FIRST_USER_PGD_NR)

// FIXME - WTF?
#define LIBRARY_TEXT_START	0x0c000000



#ifndef __ASSEMBLY__
extern void __pte_error(const char *file, int line, unsigned long val);
extern void __pmd_error(const char *file, int line, unsigned long val);
extern void __pgd_error(const char *file, int line, unsigned long val);

#define pte_ERROR(pte)		__pte_error(__FILE__, __LINE__, pte_val(pte))
#define pmd_ERROR(pmd)		__pmd_error(__FILE__, __LINE__, pmd_val(pmd))
#define pgd_ERROR(pgd)		__pgd_error(__FILE__, __LINE__, pgd_val(pgd))

/*
 * ZERO_PAGE is a global shared page that is always zero: used
 * for zero-mapped memory areas etc..
 */
extern struct page *empty_zero_page;
#define ZERO_PAGE(vaddr)	(empty_zero_page)

#define pte_pfn(pte)		(pte_val(pte) >> PAGE_SHIFT)
#define pte_page(pte)           (pfn_to_page(pte_pfn(pte)))
#define pfn_pte(pfn,prot)	(__pte(((pfn) << PAGE_SHIFT) | pgprot_val(prot)))
#define pages_to_mb(x)		((x) >> (20 - PAGE_SHIFT))
#define mk_pte(page,prot)	pfn_pte(page_to_pfn(page),prot)
#define page_pte_prot(page,prot)	mk_pte(page, prot)
#define page_pte(page)		mk_pte(page, __pgprot(0))

/*
 * Terminology: PGD = Page Directory, PMD = Page Middle Directory,
 *              PTE = Page Table Entry
 *
 * on arm26 we have no 2nd level page table. we simulate this by removing the
 * PMD.
 *
 * pgd_none is 0 to prevernt pmd_alloc() calling __pmd_alloc(). This causes it
 * to return pmd_offset(pgd,addr) which is a pointer to the pgd (IOW, a no-op).
 *
 * however, to work this way, whilst we are allocating 32 pgds, containing 32
 * PTEs, the actual work is done on the PMDs, thus:
 *
 * instead of  mm->pgd->pmd->pte
 * we have     mm->pgdpmd->pte
 *
 * IOW, think of PGD operations and PMD ones as being the same thing, just
 * that PGD stuff deals with the mm_struct side of things, wheras PMD stuff
 * deals with the pte side of things.
 *
 * additionally, we store some bits in the PGD and PTE pointers: 
 * PGDs:
 *   o The lowest (1) bit of the PGD is to determine if it is present or swap.
 *   o The 2nd bit of the PGD is unused and must be zero.
 *   o The top 6 bits of the PGD must be zero. 
 * PTEs:
 *   o The lower 5 bits of a pte are flags. bit 1 is the 'present' flag. The
 *     others determine the pages attributes.
 *
 * the pgd_val, pmd_val, and pte_val macros seem to be private to our code.
 * They get the RAW value of the PGD/PMD/PTE entry, including our flags
 * encoded into the pointers.
 * 
 * The pgd_offset, pmd_offset, and pte_offset macros are used by the kernel,
 * so they shouldnt have our flags attached.
 *
 * If you understood that, feel free to explain it to me...
 *
 */

#define _PMD_PRESENT     (0x01)

/* These definitions allow us to optimise out stuff like pmd_alloc() */
#define pgd_none(pgd)		(0) 
#define pgd_bad(pgd)		(0)
#define pgd_present(pgd)	(1)
#define pgd_clear(pgdp)		do { } while (0)

/* Whilst these handle our actual 'page directory' (the agglomeration of pgd and pmd)
 */
#define pmd_none(pmd)           (!pmd_val(pmd))
#define pmd_bad(pmd)            ((pmd_val(pmd) & 0xfc000002))
#define pmd_present(pmd)        (pmd_val(pmd) & _PMD_PRESENT)
#define set_pmd(pmd_ptr, pmd)   ((*(pmd_ptr)) = (pmd))
#define pmd_clear(pmdp)         set_pmd(pmdp, __pmd(0))

/* and these handle our pte tables */
#define pte_none(pte)           (!pte_val(pte))
#define pte_present(pte)        (pte_val(pte) & _PAGE_PRESENT)
#define set_pte(pte_ptr, pte)   ((*(pte_ptr)) = (pte))
#define set_pte_at(mm,addr,ptep,pteval) set_pte(ptep,pteval)
#define pte_clear(mm,addr,ptep)	set_pte_at((mm),(addr),(ptep), __pte(0))

/* macros to ease the getting of pointers to stuff... */
#define pgd_offset(mm, addr)	((pgd_t *)(mm)->pgd        + __pgd_index(addr))
#define pmd_offset(pgd, addr)	((pmd_t *)(pgd))
#define pte_offset(pmd, addr)   ((pte_t *)pmd_page(*(pmd)) + __pte_index(addr))

/* there is no __pmd_index as we dont use pmds */
#define __pgd_index(addr)	((addr) >> PGD_SHIFT)
#define __pte_index(addr)	(((addr) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))


/* Keep the kernel happy */
#define pgd_index(addr)         __pgd_index(addr)
#define pgd_offset_k(addr)	(pgd_offset(&init_mm, addr))

/*
 * The vmalloc() routines leaves a hole of 4kB between each vmalloced
 * area for the same reason. ;) FIXME: surely 1 page not 4k ?
 */
#define VMALLOC_START     0x01a00000
#define VMALLOC_END       0x01c00000

/* Is pmd_page supposed to return a pointer to a page in some arches? ours seems to
 * return a pointer to memory (no special alignment)
 */
#define pmd_page(pmd)  ((struct page *)(pmd_val((pmd)) & ~_PMD_PRESENT))
#define pmd_page_kernel(pmd) ((pte_t *)(pmd_val((pmd)) & ~_PMD_PRESENT))

#define pte_offset_kernel(dir,addr)     (pmd_page_kernel(*(dir)) + __pte_index(addr))

#define pte_offset_map(dir,addr)        (pmd_page_kernel(*(dir)) + __pte_index(addr))
#define pte_offset_map_nested(dir,addr) (pmd_page_kernel(*(dir)) + __pte_index(addr))
#define pte_unmap(pte)                  do { } while (0)
#define pte_unmap_nested(pte)           do { } while (0)


#define _PAGE_PRESENT   0x01
#define _PAGE_READONLY  0x02
#define _PAGE_NOT_USER  0x04
#define _PAGE_OLD       0x08
#define _PAGE_CLEAN     0x10

// an old page has never been read.
// a clean page has never been written.

/*                               -- present --   -- !dirty --  --- !write ---   ---- !user --- */
#define PAGE_NONE       __pgprot(_PAGE_PRESENT | _PAGE_CLEAN | _PAGE_READONLY | _PAGE_NOT_USER)
#define PAGE_SHARED     __pgprot(_PAGE_PRESENT | _PAGE_CLEAN                                  )
#define PAGE_COPY       __pgprot(_PAGE_PRESENT | _PAGE_CLEAN | _PAGE_READONLY                 )
#define PAGE_READONLY   __pgprot(_PAGE_PRESENT | _PAGE_CLEAN | _PAGE_READONLY                 )
#define PAGE_KERNEL     __pgprot(_PAGE_PRESENT                                | _PAGE_NOT_USER)

#define _PAGE_CHG_MASK  (PAGE_MASK | _PAGE_OLD | _PAGE_CLEAN)

/*
 * The following only work if pte_present() is true.
 * Undefined behaviour if not..
 */
#define pte_read(pte)                   (!(pte_val(pte) & _PAGE_NOT_USER))
#define pte_write(pte)                  (!(pte_val(pte) & _PAGE_READONLY))
#define pte_exec(pte)                   (!(pte_val(pte) & _PAGE_NOT_USER))
#define pte_dirty(pte)                  (!(pte_val(pte) & _PAGE_CLEAN))
#define pte_young(pte)                  (!(pte_val(pte) & _PAGE_OLD))
//ONLY when !pte_present() I think. nicked from arm32 (FIXME!)
#define pte_file(pte)                   (!(pte_val(pte) & _PAGE_OLD))

#define PTE_BIT_FUNC(fn,op)                     \
static inline pte_t pte_##fn(pte_t pte) { pte_val(pte) op; return pte; }

PTE_BIT_FUNC(wrprotect, |=  _PAGE_READONLY);
PTE_BIT_FUNC(mkwrite,   &= ~_PAGE_READONLY);
PTE_BIT_FUNC(exprotect, |=  _PAGE_NOT_USER);
PTE_BIT_FUNC(mkexec,    &= ~_PAGE_NOT_USER);
PTE_BIT_FUNC(mkclean,   |=  _PAGE_CLEAN);
PTE_BIT_FUNC(mkdirty,   &= ~_PAGE_CLEAN);
PTE_BIT_FUNC(mkold,     |=  _PAGE_OLD);
PTE_BIT_FUNC(mkyoung,   &= ~_PAGE_OLD);

/*
 * We don't store cache state bits in the page table here. FIXME - or do we?
 */
#define pgprot_noncached(prot)  (prot)
#define pgprot_writecombine(prot) (prot) //FIXME - is a no-op?

extern void pgtable_cache_init(void);

//FIXME - nicked from arm32 and brutally hacked. probably wrong.
#define pte_to_pgoff(x) (pte_val(x) >> 2)
#define pgoff_to_pte(x) __pte(((x) << 2) & ~_PAGE_OLD)

//FIXME - next line borrowed from arm32. is it right?
#define PTE_FILE_MAX_BITS       30


static 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 pgd_t swapper_pg_dir[PTRS_PER_PGD];

/* Encode and decode a swap entry.
 *
 * We support up to 32GB of swap on 4k machines
 */
#define __swp_type(x)		(((x).val >> 2) & 0x7f)
#define __swp_offset(x)		((x).val >> 9)
#define __swp_entry(type,offset) ((swp_entry_t) { ((type) << 2) | ((offset) << 9) })
#define __pte_to_swp_entry(pte)	((swp_entry_t) { pte_val(pte) })
#define __swp_entry_to_pte(swp)	((pte_t) { (swp).val })

/* Needs to be defined here and not in linux/mm.h, as it is arch dependent */
/* FIXME: this is not correct */
#define kern_addr_valid(addr)	(1)

/*
 * Conversion functions: convert a page and protection to a page entry,
 * and a page entry and page directory to the page they refer to.
 */
static inline pte_t mk_pte_phys(unsigned long physpage, pgprot_t pgprot)
{
        pte_t pte;
        pte_val(pte) = physpage | pgprot_val(pgprot);
        return pte;
}


#include <asm-generic/pgtable.h>

/*
 * remap a physical address `phys' of size `size' with page protection `prot'
 * into virtual address `from'
 */
#define io_remap_page_range(vma,from,phys,size,prot) \
		remap_pfn_range(vma, from, (phys) >> PAGE_SHIFT, size, prot)

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

#define MK_IOSPACE_PFN(space, pfn)	(pfn)
#define GET_IOSPACE(pfn)		0
#define GET_PFN(pfn)			(pfn)

#endif /* !__ASSEMBLY__ */

#endif /* _ASMARM_PGTABLE_H */