Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
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/compiler.h>
13#include <linux/linkage.h>
14
15#include <asm/addrspace.h>
16#include <asm/page.h>
17#include <asm/cachectl.h>
18#include <asm/fixmap.h>
19
20#if defined(CONFIG_PAGE_SIZE_64KB) && !defined(CONFIG_MIPS_VA_BITS_48)
21#include <asm-generic/pgtable-nopmd.h>
22#else
23#include <asm-generic/pgtable-nopud.h>
24#endif
25
26/*
27 * Each address space has 2 4K pages as its page directory, giving 1024
28 * (== PTRS_PER_PGD) 8 byte pointers to pmd tables. Each pmd table is a
29 * single 4K page, giving 512 (== PTRS_PER_PMD) 8 byte pointers to page
30 * tables. Each page table is also a single 4K page, giving 512 (==
31 * PTRS_PER_PTE) 8 byte ptes. Each pud entry is initialized to point to
32 * invalid_pmd_table, each pmd entry is initialized to point to
33 * invalid_pte_table, each pte is initialized to 0. When memory is low,
34 * and a pmd table or a page table allocation fails, empty_bad_pmd_table
35 * and empty_bad_page_table is returned back to higher layer code, so
36 * that the failure is recognized later on. Linux does not seem to
37 * handle these failures very well though. The empty_bad_page_table has
38 * invalid pte entries in it, to force page faults.
39 *
40 * Kernel mappings: kernel mappings are held in the swapper_pg_table.
41 * The layout is identical to userspace except it's indexed with the
42 * fault address - VMALLOC_START.
43 */
44
45
46/* PGDIR_SHIFT determines what a third-level page table entry can map */
47#ifdef __PAGETABLE_PMD_FOLDED
48#define PGDIR_SHIFT (PAGE_SHIFT + PAGE_SHIFT + PTE_ORDER - 3)
49#else
50
51/* PMD_SHIFT determines the size of the area a second-level page table can map */
52#define PMD_SHIFT (PAGE_SHIFT + (PAGE_SHIFT + PTE_ORDER - 3))
53#define PMD_SIZE (1UL << PMD_SHIFT)
54#define PMD_MASK (~(PMD_SIZE-1))
55
56
57#define PGDIR_SHIFT (PMD_SHIFT + (PAGE_SHIFT + PMD_ORDER - 3))
58#endif
59#define PGDIR_SIZE (1UL << PGDIR_SHIFT)
60#define PGDIR_MASK (~(PGDIR_SIZE-1))
61
62/*
63 * For 4kB page size we use a 3 level page tree and an 8kB pud, which
64 * permits us mapping 40 bits of virtual address space.
65 *
66 * We used to implement 41 bits by having an order 1 pmd level but that seemed
67 * rather pointless.
68 *
69 * For 8kB page size we use a 3 level page tree which permits a total of
70 * 8TB of address space. Alternatively a 33-bit / 8GB organization using
71 * two levels would be easy to implement.
72 *
73 * For 16kB page size we use a 2 level page tree which permits a total of
74 * 36 bits of virtual address space. We could add a third level but it seems
75 * like at the moment there's no need for this.
76 *
77 * For 64kB page size we use a 2 level page table tree for a total of 42 bits
78 * of virtual address space.
79 */
80#ifdef CONFIG_PAGE_SIZE_4KB
81#define PGD_ORDER 1
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_8KB
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#ifdef CONFIG_PAGE_SIZE_16KB
93#ifdef CONFIG_MIPS_VA_BITS_48
94#define PGD_ORDER 1
95#else
96#define PGD_ORDER 0
97#endif
98#define PUD_ORDER aieeee_attempt_to_allocate_pud
99#define PMD_ORDER 0
100#define PTE_ORDER 0
101#endif
102#ifdef CONFIG_PAGE_SIZE_32KB
103#define PGD_ORDER 0
104#define PUD_ORDER aieeee_attempt_to_allocate_pud
105#define PMD_ORDER 0
106#define PTE_ORDER 0
107#endif
108#ifdef CONFIG_PAGE_SIZE_64KB
109#define PGD_ORDER 0
110#define PUD_ORDER aieeee_attempt_to_allocate_pud
111#ifdef CONFIG_MIPS_VA_BITS_48
112#define PMD_ORDER 0
113#else
114#define PMD_ORDER aieeee_attempt_to_allocate_pmd
115#endif
116#define PTE_ORDER 0
117#endif
118
119#define PTRS_PER_PGD ((PAGE_SIZE << PGD_ORDER) / sizeof(pgd_t))
120#ifndef __PAGETABLE_PMD_FOLDED
121#define PTRS_PER_PMD ((PAGE_SIZE << PMD_ORDER) / sizeof(pmd_t))
122#endif
123#define PTRS_PER_PTE ((PAGE_SIZE << PTE_ORDER) / sizeof(pte_t))
124
125#define USER_PTRS_PER_PGD ((TASK_SIZE64 / PGDIR_SIZE)?(TASK_SIZE64 / PGDIR_SIZE):1)
126#define FIRST_USER_ADDRESS 0UL
127
128/*
129 * TLB refill handlers also map the vmalloc area into xuseg. Avoid
130 * the first couple of pages so NULL pointer dereferences will still
131 * reliably trap.
132 */
133#define VMALLOC_START (MAP_BASE + (2 * PAGE_SIZE))
134#define VMALLOC_END \
135 (MAP_BASE + \
136 min(PTRS_PER_PGD * PTRS_PER_PMD * PTRS_PER_PTE * PAGE_SIZE, \
137 (1UL << cpu_vmbits)) - (1UL << 32))
138
139#if defined(CONFIG_MODULES) && defined(KBUILD_64BIT_SYM32) && \
140 VMALLOC_START != CKSSEG
141/* Load modules into 32bit-compatible segment. */
142#define MODULE_START CKSSEG
143#define MODULE_END (FIXADDR_START-2*PAGE_SIZE)
144#endif
145
146#define pte_ERROR(e) \
147 printk("%s:%d: bad pte %016lx.\n", __FILE__, __LINE__, pte_val(e))
148#ifndef __PAGETABLE_PMD_FOLDED
149#define pmd_ERROR(e) \
150 printk("%s:%d: bad pmd %016lx.\n", __FILE__, __LINE__, pmd_val(e))
151#endif
152#define pgd_ERROR(e) \
153 printk("%s:%d: bad pgd %016lx.\n", __FILE__, __LINE__, pgd_val(e))
154
155extern pte_t invalid_pte_table[PTRS_PER_PTE];
156extern pte_t empty_bad_page_table[PTRS_PER_PTE];
157
158
159#ifndef __PAGETABLE_PMD_FOLDED
160/*
161 * For 3-level pagetables we defines these ourselves, for 2-level the
162 * definitions are supplied by <asm-generic/pgtable-nopmd.h>.
163 */
164typedef struct { unsigned long pmd; } pmd_t;
165#define pmd_val(x) ((x).pmd)
166#define __pmd(x) ((pmd_t) { (x) } )
167
168
169extern pmd_t invalid_pmd_table[PTRS_PER_PMD];
170#endif
171
172/*
173 * Empty pgd/pmd entries point to the invalid_pte_table.
174 */
175static inline int pmd_none(pmd_t pmd)
176{
177 return pmd_val(pmd) == (unsigned long) invalid_pte_table;
178}
179
180static inline int pmd_bad(pmd_t pmd)
181{
182#ifdef CONFIG_MIPS_HUGE_TLB_SUPPORT
183 /* pmd_huge(pmd) but inline */
184 if (unlikely(pmd_val(pmd) & _PAGE_HUGE))
185 return 0;
186#endif
187
188 if (unlikely(pmd_val(pmd) & ~PAGE_MASK))
189 return 1;
190
191 return 0;
192}
193
194static inline int pmd_present(pmd_t pmd)
195{
196 return pmd_val(pmd) != (unsigned long) invalid_pte_table;
197}
198
199static inline void pmd_clear(pmd_t *pmdp)
200{
201 pmd_val(*pmdp) = ((unsigned long) invalid_pte_table);
202}
203#ifndef __PAGETABLE_PMD_FOLDED
204
205/*
206 * Empty pud entries point to the invalid_pmd_table.
207 */
208static inline int pud_none(pud_t pud)
209{
210 return pud_val(pud) == (unsigned long) invalid_pmd_table;
211}
212
213static inline int pud_bad(pud_t pud)
214{
215 return pud_val(pud) & ~PAGE_MASK;
216}
217
218static inline int pud_present(pud_t pud)
219{
220 return pud_val(pud) != (unsigned long) invalid_pmd_table;
221}
222
223static inline void pud_clear(pud_t *pudp)
224{
225 pud_val(*pudp) = ((unsigned long) invalid_pmd_table);
226}
227#endif
228
229#define pte_page(x) pfn_to_page(pte_pfn(x))
230
231#ifdef CONFIG_CPU_VR41XX
232#define pte_pfn(x) ((unsigned long)((x).pte >> (PAGE_SHIFT + 2)))
233#define pfn_pte(pfn, prot) __pte(((pfn) << (PAGE_SHIFT + 2)) | pgprot_val(prot))
234#else
235#define pte_pfn(x) ((unsigned long)((x).pte >> _PFN_SHIFT))
236#define pfn_pte(pfn, prot) __pte(((pfn) << _PFN_SHIFT) | pgprot_val(prot))
237#define pfn_pmd(pfn, prot) __pmd(((pfn) << _PFN_SHIFT) | pgprot_val(prot))
238#endif
239
240#define __pgd_offset(address) pgd_index(address)
241#define __pud_offset(address) (((address) >> PUD_SHIFT) & (PTRS_PER_PUD-1))
242#define __pmd_offset(address) pmd_index(address)
243
244/* to find an entry in a kernel page-table-directory */
245#define pgd_offset_k(address) pgd_offset(&init_mm, address)
246
247#define pgd_index(address) (((address) >> PGDIR_SHIFT) & (PTRS_PER_PGD-1))
248#define pmd_index(address) (((address) >> PMD_SHIFT) & (PTRS_PER_PMD-1))
249
250/* to find an entry in a page-table-directory */
251#define pgd_offset(mm, addr) ((mm)->pgd + pgd_index(addr))
252
253#ifndef __PAGETABLE_PMD_FOLDED
254static inline unsigned long pud_page_vaddr(pud_t pud)
255{
256 return pud_val(pud);
257}
258#define pud_phys(pud) virt_to_phys((void *)pud_val(pud))
259#define pud_page(pud) (pfn_to_page(pud_phys(pud) >> PAGE_SHIFT))
260
261/* Find an entry in the second-level page table.. */
262static inline pmd_t *pmd_offset(pud_t * pud, unsigned long address)
263{
264 return (pmd_t *) pud_page_vaddr(*pud) + pmd_index(address);
265}
266#endif
267
268/* Find an entry in the third-level page table.. */
269#define __pte_offset(address) \
270 (((address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
271#define pte_offset(dir, address) \
272 ((pte_t *) pmd_page_vaddr(*(dir)) + __pte_offset(address))
273#define pte_offset_kernel(dir, address) \
274 ((pte_t *) pmd_page_vaddr(*(dir)) + __pte_offset(address))
275#define pte_offset_map(dir, address) \
276 ((pte_t *)page_address(pmd_page(*(dir))) + __pte_offset(address))
277#define pte_unmap(pte) ((void)(pte))
278
279/*
280 * Initialize a new pgd / pmd table with invalid pointers.
281 */
282extern void pgd_init(unsigned long page);
283extern void pmd_init(unsigned long page, unsigned long pagetable);
284
285/*
286 * Non-present pages: high 40 bits are offset, next 8 bits type,
287 * low 16 bits zero.
288 */
289static inline pte_t mk_swap_pte(unsigned long type, unsigned long offset)
290{ pte_t pte; pte_val(pte) = (type << 16) | (offset << 24); return pte; }
291
292#define __swp_type(x) (((x).val >> 16) & 0xff)
293#define __swp_offset(x) ((x).val >> 24)
294#define __swp_entry(type, offset) ((swp_entry_t) { pte_val(mk_swap_pte((type), (offset))) })
295#define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
296#define __swp_entry_to_pte(x) ((pte_t) { (x).val })
297
298#endif /* _ASM_PGTABLE_64_H */