File: /usr/include/asm/pgtable-2level.h

1     #ifndef _I386_PGTABLE_2LEVEL_H
2     #define _I386_PGTABLE_2LEVEL_H
3     
4     /*
5      * traditional i386 two-level paging structure:
6      */
7     
8     #define PGDIR_SHIFT	22
9     #define PTRS_PER_PGD	1024
10     
11     /*
12      * the i386 is two-level, so we don't really have any
13      * PMD directory physically.
14      */
15     #define PMD_SHIFT	22
16     #define PTRS_PER_PMD	1
17     
18     #define PTRS_PER_PTE	1024
19     
20     #define pte_ERROR(e) \
21     	printk("%s:%d: bad pte %08lx.\n", __FILE__, __LINE__, (e).pte_low)
22     #define pmd_ERROR(e) \
23     	printk("%s:%d: bad pmd %08lx.\n", __FILE__, __LINE__, pmd_val(e))
24     #define pgd_ERROR(e) \
25     	printk("%s:%d: bad pgd %08lx.\n", __FILE__, __LINE__, pgd_val(e))
26     
27     /*
28      * The "pgd_xxx()" functions here are trivial for a folded two-level
29      * setup: the pgd is never bad, and a pmd always exists (as it's folded
30      * into the pgd entry)
31      */
32     extern inline int pgd_none(pgd_t pgd)		{ return 0; }
33     extern inline int pgd_bad(pgd_t pgd)		{ return 0; }
34     extern inline int pgd_present(pgd_t pgd)	{ return 1; }
35     #define pgd_clear(xp)				do { } while (0)
36     
37     /*
38      * Certain architectures need to do special things when PTEs
39      * within a page table are directly modified.  Thus, the following
40      * hook is made available.
41      */
42     #define set_pte(pteptr, pteval) (*(pteptr) = pteval)
43     /*
44      * (pmds are folded into pgds so this doesnt get actually called,
45      * but the define is needed for a generic inline function.)
46      */
47     #define set_pmd(pmdptr, pmdval) (*(pmdptr) = pmdval)
48     #define set_pgd(pgdptr, pgdval) (*(pgdptr) = pgdval)
49     
50     #define pgd_page(pgd) \
51     ((unsigned long) __va(pgd_val(pgd) & PAGE_MASK))
52     
53     extern inline pmd_t * pmd_offset(pgd_t * dir, unsigned long address)
54     {
55     	return (pmd_t *) dir;
56     }
57     #define ptep_get_and_clear(xp)	__pte(xchg(&(xp)->pte_low, 0))
58     #define pte_same(a, b)		((a).pte_low == (b).pte_low)
59     #define pte_page(x)		(mem_map+((unsigned long)(((x).pte_low >> PAGE_SHIFT))))
60     #define pte_none(x)		(!(x).pte_low)
61     #define __mk_pte(page_nr,pgprot) __pte(((page_nr) << PAGE_SHIFT) | pgprot_val(pgprot))
62     
63     #endif /* _I386_PGTABLE_2LEVEL_H */
64