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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /include/asm-arm26/pgtable.h
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
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diff --git a/include/asm-arm26/pgtable.h b/include/asm-arm26/pgtable.h
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1/*
2 * linux/include/asm-arm26/pgtable.h
3 *
4 * Copyright (C) 2000-2002 Russell King
5 * Copyright (C) 2003 Ian Molton
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 */
11#ifndef _ASMARM_PGTABLE_H
12#define _ASMARM_PGTABLE_H
13
14#include <asm-generic/4level-fixup.h>
15
16#include <linux/config.h>
17#include <asm/memory.h>
18
19/*
20 * The table below defines the page protection levels that we insert into our
21 * Linux page table version. These get translated into the best that the
22 * architecture can perform. Note that on most ARM hardware:
23 * 1) We cannot do execute protection
24 * 2) If we could do execute protection, then read is implied
25 * 3) write implies read permissions
26 */
27#define __P000 PAGE_NONE
28#define __P001 PAGE_READONLY
29#define __P010 PAGE_COPY
30#define __P011 PAGE_COPY
31#define __P100 PAGE_READONLY
32#define __P101 PAGE_READONLY
33#define __P110 PAGE_COPY
34#define __P111 PAGE_COPY
35
36#define __S000 PAGE_NONE
37#define __S001 PAGE_READONLY
38#define __S010 PAGE_SHARED
39#define __S011 PAGE_SHARED
40#define __S100 PAGE_READONLY
41#define __S101 PAGE_READONLY
42#define __S110 PAGE_SHARED
43#define __S111 PAGE_SHARED
44
45/*
46 * PMD_SHIFT determines the size of the area a second-level page table can map
47 * PGDIR_SHIFT determines what a third-level page table entry can map
48 */
49#define PGD_SHIFT 25
50#define PMD_SHIFT 20
51
52#define PGD_SIZE (1UL << PGD_SHIFT)
53#define PGD_MASK (~(PGD_SIZE-1))
54#define PMD_SIZE (1UL << PMD_SHIFT)
55#define PMD_MASK (~(PMD_SIZE-1))
56
57/* The kernel likes to use these names for the above (ick) */
58#define PGDIR_SIZE PGD_SIZE
59#define PGDIR_MASK PGD_MASK
60
61#define PTRS_PER_PGD 32
62#define PTRS_PER_PMD 1
63#define PTRS_PER_PTE 32
64
65#define FIRST_USER_PGD_NR 1
66#define USER_PTRS_PER_PGD ((TASK_SIZE/PGD_SIZE) - FIRST_USER_PGD_NR)
67
68// FIXME - WTF?
69#define LIBRARY_TEXT_START 0x0c000000
70
71
72
73#ifndef __ASSEMBLY__
74extern void __pte_error(const char *file, int line, unsigned long val);
75extern void __pmd_error(const char *file, int line, unsigned long val);
76extern void __pgd_error(const char *file, int line, unsigned long val);
77
78#define pte_ERROR(pte) __pte_error(__FILE__, __LINE__, pte_val(pte))
79#define pmd_ERROR(pmd) __pmd_error(__FILE__, __LINE__, pmd_val(pmd))
80#define pgd_ERROR(pgd) __pgd_error(__FILE__, __LINE__, pgd_val(pgd))
81
82/*
83 * ZERO_PAGE is a global shared page that is always zero: used
84 * for zero-mapped memory areas etc..
85 */
86extern struct page *empty_zero_page;
87#define ZERO_PAGE(vaddr) (empty_zero_page)
88
89#define pte_pfn(pte) (pte_val(pte) >> PAGE_SHIFT)
90#define pte_page(pte) (pfn_to_page(pte_pfn(pte)))
91#define pfn_pte(pfn,prot) (__pte(((pfn) << PAGE_SHIFT) | pgprot_val(prot)))
92#define pages_to_mb(x) ((x) >> (20 - PAGE_SHIFT))
93#define mk_pte(page,prot) pfn_pte(page_to_pfn(page),prot)
94#define page_pte_prot(page,prot) mk_pte(page, prot)
95#define page_pte(page) mk_pte(page, __pgprot(0))
96
97/*
98 * Terminology: PGD = Page Directory, PMD = Page Middle Directory,
99 * PTE = Page Table Entry
100 *
101 * on arm26 we have no 2nd level page table. we simulate this by removing the
102 * PMD.
103 *
104 * pgd_none is 0 to prevernt pmd_alloc() calling __pmd_alloc(). This causes it
105 * to return pmd_offset(pgd,addr) which is a pointer to the pgd (IOW, a no-op).
106 *
107 * however, to work this way, whilst we are allocating 32 pgds, containing 32
108 * PTEs, the actual work is done on the PMDs, thus:
109 *
110 * instead of mm->pgd->pmd->pte
111 * we have mm->pgdpmd->pte
112 *
113 * IOW, think of PGD operations and PMD ones as being the same thing, just
114 * that PGD stuff deals with the mm_struct side of things, wheras PMD stuff
115 * deals with the pte side of things.
116 *
117 * additionally, we store some bits in the PGD and PTE pointers:
118 * PGDs:
119 * o The lowest (1) bit of the PGD is to determine if it is present or swap.
120 * o The 2nd bit of the PGD is unused and must be zero.
121 * o The top 6 bits of the PGD must be zero.
122 * PTEs:
123 * o The lower 5 bits of a pte are flags. bit 1 is the 'present' flag. The
124 * others determine the pages attributes.
125 *
126 * the pgd_val, pmd_val, and pte_val macros seem to be private to our code.
127 * They get the RAW value of the PGD/PMD/PTE entry, including our flags
128 * encoded into the pointers.
129 *
130 * The pgd_offset, pmd_offset, and pte_offset macros are used by the kernel,
131 * so they shouldnt have our flags attached.
132 *
133 * If you understood that, feel free to explain it to me...
134 *
135 */
136
137#define _PMD_PRESENT (0x01)
138
139/* These definitions allow us to optimise out stuff like pmd_alloc() */
140#define pgd_none(pgd) (0)
141#define pgd_bad(pgd) (0)
142#define pgd_present(pgd) (1)
143#define pgd_clear(pgdp) do { } while (0)
144
145/* Whilst these handle our actual 'page directory' (the agglomeration of pgd and pmd)
146 */
147#define pmd_none(pmd) (!pmd_val(pmd))
148#define pmd_bad(pmd) ((pmd_val(pmd) & 0xfc000002))
149#define pmd_present(pmd) (pmd_val(pmd) & _PMD_PRESENT)
150#define set_pmd(pmd_ptr, pmd) ((*(pmd_ptr)) = (pmd))
151#define pmd_clear(pmdp) set_pmd(pmdp, __pmd(0))
152
153/* and these handle our pte tables */
154#define pte_none(pte) (!pte_val(pte))
155#define pte_present(pte) (pte_val(pte) & _PAGE_PRESENT)
156#define set_pte(pte_ptr, pte) ((*(pte_ptr)) = (pte))
157#define set_pte_at(mm,addr,ptep,pteval) set_pte(ptep,pteval)
158#define pte_clear(mm,addr,ptep) set_pte_at((mm),(addr),(ptep), __pte(0))
159
160/* macros to ease the getting of pointers to stuff... */
161#define pgd_offset(mm, addr) ((pgd_t *)(mm)->pgd + __pgd_index(addr))
162#define pmd_offset(pgd, addr) ((pmd_t *)(pgd))
163#define pte_offset(pmd, addr) ((pte_t *)pmd_page(*(pmd)) + __pte_index(addr))
164
165/* there is no __pmd_index as we dont use pmds */
166#define __pgd_index(addr) ((addr) >> PGD_SHIFT)
167#define __pte_index(addr) (((addr) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
168
169
170/* Keep the kernel happy */
171#define pgd_index(addr) __pgd_index(addr)
172#define pgd_offset_k(addr) (pgd_offset(&init_mm, addr))
173
174/*
175 * The vmalloc() routines leaves a hole of 4kB between each vmalloced
176 * area for the same reason. ;) FIXME: surely 1 page not 4k ?
177 */
178#define VMALLOC_START 0x01a00000
179#define VMALLOC_END 0x01c00000
180
181/* Is pmd_page supposed to return a pointer to a page in some arches? ours seems to
182 * return a pointer to memory (no special alignment)
183 */
184#define pmd_page(pmd) ((struct page *)(pmd_val((pmd)) & ~_PMD_PRESENT))
185#define pmd_page_kernel(pmd) ((pte_t *)(pmd_val((pmd)) & ~_PMD_PRESENT))
186
187#define pte_offset_kernel(dir,addr) (pmd_page_kernel(*(dir)) + __pte_index(addr))
188
189#define pte_offset_map(dir,addr) (pmd_page_kernel(*(dir)) + __pte_index(addr))
190#define pte_offset_map_nested(dir,addr) (pmd_page_kernel(*(dir)) + __pte_index(addr))
191#define pte_unmap(pte) do { } while (0)
192#define pte_unmap_nested(pte) do { } while (0)
193
194
195#define _PAGE_PRESENT 0x01
196#define _PAGE_READONLY 0x02
197#define _PAGE_NOT_USER 0x04
198#define _PAGE_OLD 0x08
199#define _PAGE_CLEAN 0x10
200
201// an old page has never been read.
202// a clean page has never been written.
203
204/* -- present -- -- !dirty -- --- !write --- ---- !user --- */
205#define PAGE_NONE __pgprot(_PAGE_PRESENT | _PAGE_CLEAN | _PAGE_READONLY | _PAGE_NOT_USER)
206#define PAGE_SHARED __pgprot(_PAGE_PRESENT | _PAGE_CLEAN )
207#define PAGE_COPY __pgprot(_PAGE_PRESENT | _PAGE_CLEAN | _PAGE_READONLY )
208#define PAGE_READONLY __pgprot(_PAGE_PRESENT | _PAGE_CLEAN | _PAGE_READONLY )
209#define PAGE_KERNEL __pgprot(_PAGE_PRESENT | _PAGE_NOT_USER)
210
211#define _PAGE_CHG_MASK (PAGE_MASK | _PAGE_OLD | _PAGE_CLEAN)
212
213/*
214 * The following only work if pte_present() is true.
215 * Undefined behaviour if not..
216 */
217#define pte_read(pte) (!(pte_val(pte) & _PAGE_NOT_USER))
218#define pte_write(pte) (!(pte_val(pte) & _PAGE_READONLY))
219#define pte_exec(pte) (!(pte_val(pte) & _PAGE_NOT_USER))
220#define pte_dirty(pte) (!(pte_val(pte) & _PAGE_CLEAN))
221#define pte_young(pte) (!(pte_val(pte) & _PAGE_OLD))
222//ONLY when !pte_present() I think. nicked from arm32 (FIXME!)
223#define pte_file(pte) (!(pte_val(pte) & _PAGE_OLD))
224
225#define PTE_BIT_FUNC(fn,op) \
226static inline pte_t pte_##fn(pte_t pte) { pte_val(pte) op; return pte; }
227
228PTE_BIT_FUNC(wrprotect, |= _PAGE_READONLY);
229PTE_BIT_FUNC(mkwrite, &= ~_PAGE_READONLY);
230PTE_BIT_FUNC(exprotect, |= _PAGE_NOT_USER);
231PTE_BIT_FUNC(mkexec, &= ~_PAGE_NOT_USER);
232PTE_BIT_FUNC(mkclean, |= _PAGE_CLEAN);
233PTE_BIT_FUNC(mkdirty, &= ~_PAGE_CLEAN);
234PTE_BIT_FUNC(mkold, |= _PAGE_OLD);
235PTE_BIT_FUNC(mkyoung, &= ~_PAGE_OLD);
236
237/*
238 * We don't store cache state bits in the page table here. FIXME - or do we?
239 */
240#define pgprot_noncached(prot) (prot)
241#define pgprot_writecombine(prot) (prot) //FIXME - is a no-op?
242
243extern void pgtable_cache_init(void);
244
245//FIXME - nicked from arm32 and brutally hacked. probably wrong.
246#define pte_to_pgoff(x) (pte_val(x) >> 2)
247#define pgoff_to_pte(x) __pte(((x) << 2) & ~_PAGE_OLD)
248
249//FIXME - next line borrowed from arm32. is it right?
250#define PTE_FILE_MAX_BITS 30
251
252
253static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
254{
255 pte_val(pte) = (pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot);
256 return pte;
257}
258
259extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
260
261/* Encode and decode a swap entry.
262 *
263 * We support up to 32GB of swap on 4k machines
264 */
265#define __swp_type(x) (((x).val >> 2) & 0x7f)
266#define __swp_offset(x) ((x).val >> 9)
267#define __swp_entry(type,offset) ((swp_entry_t) { ((type) << 2) | ((offset) << 9) })
268#define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
269#define __swp_entry_to_pte(swp) ((pte_t) { (swp).val })
270
271/* Needs to be defined here and not in linux/mm.h, as it is arch dependent */
272/* FIXME: this is not correct */
273#define kern_addr_valid(addr) (1)
274
275/*
276 * Conversion functions: convert a page and protection to a page entry,
277 * and a page entry and page directory to the page they refer to.
278 */
279static inline pte_t mk_pte_phys(unsigned long physpage, pgprot_t pgprot)
280{
281 pte_t pte;
282 pte_val(pte) = physpage | pgprot_val(pgprot);
283 return pte;
284}
285
286
287#include <asm-generic/pgtable.h>
288
289/*
290 * remap a physical address `phys' of size `size' with page protection `prot'
291 * into virtual address `from'
292 */
293#define io_remap_page_range(vma,from,phys,size,prot) \
294 remap_pfn_range(vma, from, (phys) >> PAGE_SHIFT, size, prot)
295
296#define io_remap_pfn_range(vma,from,pfn,size,prot) \
297 remap_pfn_range(vma, from, pfn, size, prot)
298
299#define MK_IOSPACE_PFN(space, pfn) (pfn)
300#define GET_IOSPACE(pfn) 0
301#define GET_PFN(pfn) (pfn)
302
303#endif /* !__ASSEMBLY__ */
304
305#endif /* _ASMARM_PGTABLE_H */