1/*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License.  See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * Copyright (C) 1994, 95, 96, 97, 98, 99, 2000, 2003 Ralf Baechle
7 * Copyright (C) 1999, 2000, 2001 Silicon Graphics, Inc.
8 */
9#ifndef _ASM_PGTABLE_64_H
10#define _ASM_PGTABLE_64_H
11
12#include <linux/linkage.h>
13
14#include <asm/addrspace.h>
15#include <asm/page.h>
16#include <asm/cachectl.h>
17#include <asm/fixmap.h>
18
19#include <asm-generic/pgtable-nopud.h>
20
21/*
22 * Each address space has 2 4K pages as its page directory, giving 1024
23 * (== PTRS_PER_PGD) 8 byte pointers to pmd tables. Each pmd table is a
24 * single 4K page, giving 512 (== PTRS_PER_PMD) 8 byte pointers to page
25 * tables. Each page table is also a single 4K page, giving 512 (==
26 * PTRS_PER_PTE) 8 byte ptes. Each pud entry is initialized to point to
27 * invalid_pmd_table, each pmd entry is initialized to point to
28 * invalid_pte_table, each pte is initialized to 0. When memory is low,
29 * and a pmd table or a page table allocation fails, empty_bad_pmd_table
30 * and empty_bad_page_table is returned back to higher layer code, so
31 * that the failure is recognized later on. Linux does not seem to
32 * handle these failures very well though. The empty_bad_page_table has
33 * invalid pte entries in it, to force page faults.
34 *
35 * Kernel mappings: kernel mappings are held in the swapper_pg_table.
36 * The layout is identical to userspace except it's indexed with the
37 * fault address - VMALLOC_START.
38 */
39
40/* PMD_SHIFT determines the size of the area a second-level page table can map */
41#define PMD_SHIFT	(PAGE_SHIFT + (PAGE_SHIFT + PTE_ORDER - 3))
42#define PMD_SIZE	(1UL << PMD_SHIFT)
43#define PMD_MASK	(~(PMD_SIZE-1))
44
45/* PGDIR_SHIFT determines what a third-level page table entry can map */
46#define PGDIR_SHIFT	(PMD_SHIFT + (PAGE_SHIFT + PMD_ORDER - 3))
47#define PGDIR_SIZE	(1UL << PGDIR_SHIFT)
48#define PGDIR_MASK	(~(PGDIR_SIZE-1))
49
50/*
51 * For 4kB page size we use a 3 level page tree and an 8kB pud, which
52 * permits us mapping 40 bits of virtual address space.
53 *
54 * We used to implement 41 bits by having an order 1 pmd level but that seemed
55 * rather pointless.
56 *
57 * For 8kB page size we use a 3 level page tree which permits a total of
58 * 8TB of address space.  Alternatively a 33-bit / 8GB organization using
59 * two levels would be easy to implement.
60 *
61 * For 16kB page size we use a 2 level page tree which permits a total of
62 * 36 bits of virtual address space.  We could add a third level but it seems
63 * like at the moment there's no need for this.
64 *
65 * For 64kB page size we use a 2 level page table tree for a total of 42 bits
66 * of virtual address space.
67 */
68#ifdef CONFIG_PAGE_SIZE_4KB
69#define PGD_ORDER		1
70#define PUD_ORDER		aieeee_attempt_to_allocate_pud
71#define PMD_ORDER		0
72#define PTE_ORDER		0
73#endif
74#ifdef CONFIG_PAGE_SIZE_8KB
75#define PGD_ORDER		0
76#define PUD_ORDER		aieeee_attempt_to_allocate_pud
77#define PMD_ORDER		0
78#define PTE_ORDER		0
79#endif
80#ifdef CONFIG_PAGE_SIZE_16KB
81#define PGD_ORDER		0
82#define PUD_ORDER		aieeee_attempt_to_allocate_pud
83#define PMD_ORDER		0
84#define PTE_ORDER		0
85#endif
86#ifdef CONFIG_PAGE_SIZE_64KB
87#define PGD_ORDER		0
88#define PUD_ORDER		aieeee_attempt_to_allocate_pud
89#define PMD_ORDER		0
90#define PTE_ORDER		0
91#endif
92
93#define PTRS_PER_PGD	((PAGE_SIZE << PGD_ORDER) / sizeof(pgd_t))
94#define PTRS_PER_PMD	((PAGE_SIZE << PMD_ORDER) / sizeof(pmd_t))
95#define PTRS_PER_PTE	((PAGE_SIZE << PTE_ORDER) / sizeof(pte_t))
96
97#if PGDIR_SIZE >= TASK_SIZE
98#define USER_PTRS_PER_PGD       (1)
99#else
100#define USER_PTRS_PER_PGD	(TASK_SIZE / PGDIR_SIZE)
101#endif
102#define FIRST_USER_ADDRESS	0UL
103
104#define VMALLOC_START		MAP_BASE
105#define VMALLOC_END	\
106	(VMALLOC_START + PTRS_PER_PGD * PTRS_PER_PMD * PTRS_PER_PTE * PAGE_SIZE)
107#if defined(CONFIG_MODULES) && !defined(CONFIG_BUILD_ELF64) && VMALLOC_START != CKSSEG
108/* Load modules into 32bit-compatible segment. */
109#define MODULE_START	CKSSEG
110#define MODULE_END	(FIXADDR_START-2*PAGE_SIZE)
111extern pgd_t module_pg_dir[PTRS_PER_PGD];
112#endif
113
114#define pte_ERROR(e) \
115	printk("%s:%d: bad pte %016lx.\n", __FILE__, __LINE__, pte_val(e))
116#define pmd_ERROR(e) \
117	printk("%s:%d: bad pmd %016lx.\n", __FILE__, __LINE__, pmd_val(e))
118#define pgd_ERROR(e) \
119	printk("%s:%d: bad pgd %016lx.\n", __FILE__, __LINE__, pgd_val(e))
120
121extern pte_t invalid_pte_table[PTRS_PER_PTE];
122extern pte_t empty_bad_page_table[PTRS_PER_PTE];
123extern pmd_t invalid_pmd_table[PTRS_PER_PMD];
124extern pmd_t empty_bad_pmd_table[PTRS_PER_PMD];
125
126/*
127 * Empty pgd/pmd entries point to the invalid_pte_table.
128 */
129static inline int pmd_none(pmd_t pmd)
130{
131	return pmd_val(pmd) == (unsigned long) invalid_pte_table;
132}
133
134#define pmd_bad(pmd)		(pmd_val(pmd) & ~PAGE_MASK)
135
136static inline int pmd_present(pmd_t pmd)
137{
138	return pmd_val(pmd) != (unsigned long) invalid_pte_table;
139}
140
141static inline void pmd_clear(pmd_t *pmdp)
142{
143	pmd_val(*pmdp) = ((unsigned long) invalid_pte_table);
144}
145
146/*
147 * Empty pud entries point to the invalid_pmd_table.
148 */
149static inline int pud_none(pud_t pud)
150{
151	return pud_val(pud) == (unsigned long) invalid_pmd_table;
152}
153
154static inline int pud_bad(pud_t pud)
155{
156	return pud_val(pud) & ~PAGE_MASK;
157}
158
159static inline int pud_present(pud_t pud)
160{
161	return pud_val(pud) != (unsigned long) invalid_pmd_table;
162}
163
164static inline void pud_clear(pud_t *pudp)
165{
166	pud_val(*pudp) = ((unsigned long) invalid_pmd_table);
167}
168
169#define pte_page(x)		pfn_to_page(pte_pfn(x))
170
171#ifdef CONFIG_CPU_VR41XX
172#define pte_pfn(x)		((unsigned long)((x).pte >> (PAGE_SHIFT + 2)))
173#define pfn_pte(pfn, prot)	__pte(((pfn) << (PAGE_SHIFT + 2)) | pgprot_val(prot))
174#else
175#define pte_pfn(x)		((unsigned long)((x).pte >> PAGE_SHIFT))
176#define pfn_pte(pfn, prot)	__pte(((pfn) << PAGE_SHIFT) | pgprot_val(prot))
177#endif
178
179#define __pgd_offset(address)	pgd_index(address)
180#define __pud_offset(address)	(((address) >> PUD_SHIFT) & (PTRS_PER_PUD-1))
181#define __pmd_offset(address)	pmd_index(address)
182
183/* to find an entry in a kernel page-table-directory */
184#ifdef MODULE_START
185#define pgd_offset_k(address) \
186	((address) >= MODULE_START ? module_pg_dir : pgd_offset(&init_mm, 0UL))
187#else
188#define pgd_offset_k(address) pgd_offset(&init_mm, 0UL)
189#endif
190
191#define pgd_index(address)	(((address) >> PGDIR_SHIFT) & (PTRS_PER_PGD-1))
192#define pmd_index(address)	(((address) >> PMD_SHIFT) & (PTRS_PER_PMD-1))
193
194/* to find an entry in a page-table-directory */
195#define pgd_offset(mm,addr)	((mm)->pgd + pgd_index(addr))
196
197static inline unsigned long pud_page_vaddr(pud_t pud)
198{
199	return pud_val(pud);
200}
201#define pud_phys(pud)		virt_to_phys((void *)pud_val(pud))
202#define pud_page(pud)		(pfn_to_page(pud_phys(pud) >> PAGE_SHIFT))
203
204/* Find an entry in the second-level page table.. */
205static inline pmd_t *pmd_offset(pud_t * pud, unsigned long address)
206{
207	return (pmd_t *) pud_page_vaddr(*pud) + pmd_index(address);
208}
209
210/* Find an entry in the third-level page table.. */
211#define __pte_offset(address)						\
212	(((address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
213#define pte_offset(dir, address)					\
214	((pte_t *) pmd_page_vaddr(*(dir)) + __pte_offset(address))
215#define pte_offset_kernel(dir, address)					\
216	((pte_t *) pmd_page_vaddr(*(dir)) + __pte_offset(address))
217#define pte_offset_map(dir, address)					\
218	((pte_t *)page_address(pmd_page(*(dir))) + __pte_offset(address))
219#define pte_offset_map_nested(dir, address)				\
220	((pte_t *)page_address(pmd_page(*(dir))) + __pte_offset(address))
221#define pte_unmap(pte) ((void)(pte))
222#define pte_unmap_nested(pte) ((void)(pte))
223
224/*
225 * Initialize a new pgd / pmd table with invalid pointers.
226 */
227extern void pgd_init(unsigned long page);
228extern void pmd_init(unsigned long page, unsigned long pagetable);
229
230/*
231 * Non-present pages:  high 24 bits are offset, next 8 bits type,
232 * low 32 bits zero.
233 */
234static inline pte_t mk_swap_pte(unsigned long type, unsigned long offset)
235{ pte_t pte; pte_val(pte) = (type << 32) | (offset << 40); return pte; }
236
237#define __swp_type(x)		(((x).val >> 32) & 0xff)
238#define __swp_offset(x)		((x).val >> 40)
239#define __swp_entry(type,offset) ((swp_entry_t) { pte_val(mk_swap_pte((type),(offset))) })
240#define __pte_to_swp_entry(pte)	((swp_entry_t) { pte_val(pte) })
241#define __swp_entry_to_pte(x)	((pte_t) { (x).val })
242
243/*
244 * Bits 0, 4, 6, and 7 are taken. Let's leave bits 1, 2, 3, and 5 alone to
245 * make things easier, and only use the upper 56 bits for the page offset...
246 */
247#define PTE_FILE_MAX_BITS	56
248
249#define pte_to_pgoff(_pte)	((_pte).pte >> 8)
250#define pgoff_to_pte(off)	((pte_t) { ((off) << 8) | _PAGE_FILE })
251
252#endif /* _ASM_PGTABLE_64_H */
253