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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_32_H
10#define _ASM_PGTABLE_32_H
11
12#include <asm/addrspace.h>
13#include <asm/page.h>
14
15#include <linux/linkage.h>
16#include <asm/cachectl.h>
17#include <asm/fixmap.h>
18
19#include <asm-generic/pgtable-nopmd.h>
20
21#ifdef CONFIG_HIGHMEM
22#include <asm/highmem.h>
23#endif
24
25/*
26 * Regarding 32-bit MIPS huge page support (and the tradeoff it entails):
27 *
28 * We use the same huge page sizes as 64-bit MIPS. Assuming a 4KB page size,
29 * our 2-level table layout would normally have a PGD entry cover a contiguous
30 * 4MB virtual address region (pointing to a 4KB PTE page of 1,024 32-bit pte_t
31 * pointers, each pointing to a 4KB physical page). The problem is that 4MB,
32 * spanning both halves of a TLB EntryLo0,1 pair, requires 2MB hardware page
33 * support, not one of the standard supported sizes (1MB,4MB,16MB,...).
34 * To correct for this, when huge pages are enabled, we halve the number of
35 * pointers a PTE page holds, making its last half go to waste. Correspondingly,
36 * we double the number of PGD pages. Overall, page table memory overhead
37 * increases to match 64-bit MIPS, but PTE lookups remain CPU cache-friendly.
38 *
39 * NOTE: We don't yet support huge pages if extended-addressing is enabled
40 * (i.e. EVA, XPA, 36-bit Alchemy/Netlogic).
41 */
42
43extern int temp_tlb_entry;
44
45/*
46 * - add_temporary_entry() add a temporary TLB entry. We use TLB entries
47 * starting at the top and working down. This is for populating the
48 * TLB before trap_init() puts the TLB miss handler in place. It
49 * should be used only for entries matching the actual page tables,
50 * to prevent inconsistencies.
51 */
52extern int add_temporary_entry(unsigned long entrylo0, unsigned long entrylo1,
53 unsigned long entryhi, unsigned long pagemask);
54
55/*
56 * Basically we have the same two-level (which is the logical three level
57 * Linux page table layout folded) page tables as the i386. Some day
58 * when we have proper page coloring support we can have a 1% quicker
59 * tlb refill handling mechanism, but for now it is a bit slower but
60 * works even with the cache aliasing problem the R4k and above have.
61 */
62
63/* PGDIR_SHIFT determines what a third-level page table entry can map */
64#if defined(CONFIG_MIPS_HUGE_TLB_SUPPORT) && !defined(CONFIG_PHYS_ADDR_T_64BIT)
65# define PGDIR_SHIFT (2 * PAGE_SHIFT - PTE_T_LOG2 - 1)
66#else
67# define PGDIR_SHIFT (2 * PAGE_SHIFT - PTE_T_LOG2)
68#endif
69
70#define PGDIR_SIZE (1UL << PGDIR_SHIFT)
71#define PGDIR_MASK (~(PGDIR_SIZE-1))
72
73/*
74 * Entries per page directory level: we use two-level, so
75 * we don't really have any PUD/PMD directory physically.
76 */
77#if defined(CONFIG_MIPS_HUGE_TLB_SUPPORT) && !defined(CONFIG_PHYS_ADDR_T_64BIT)
78# define __PGD_TABLE_ORDER (32 - 3 * PAGE_SHIFT + PGD_T_LOG2 + PTE_T_LOG2 + 1)
79#else
80# define __PGD_TABLE_ORDER (32 - 3 * PAGE_SHIFT + PGD_T_LOG2 + PTE_T_LOG2)
81#endif
82
83#define PGD_TABLE_ORDER (__PGD_TABLE_ORDER >= 0 ? __PGD_TABLE_ORDER : 0)
84#define PUD_TABLE_ORDER aieeee_attempt_to_allocate_pud
85#define PMD_TABLE_ORDER aieeee_attempt_to_allocate_pmd
86
87#define PTRS_PER_PGD (USER_PTRS_PER_PGD * 2)
88#if defined(CONFIG_MIPS_HUGE_TLB_SUPPORT) && !defined(CONFIG_PHYS_ADDR_T_64BIT)
89# define PTRS_PER_PTE (PAGE_SIZE / sizeof(pte_t) / 2)
90#else
91# define PTRS_PER_PTE (PAGE_SIZE / sizeof(pte_t))
92#endif
93
94#define USER_PTRS_PER_PGD (0x80000000UL/PGDIR_SIZE)
95
96#define VMALLOC_START MAP_BASE
97
98#define PKMAP_END ((FIXADDR_START) & ~((LAST_PKMAP << PAGE_SHIFT)-1))
99#define PKMAP_BASE (PKMAP_END - PAGE_SIZE * LAST_PKMAP)
100
101#ifdef CONFIG_HIGHMEM
102# define VMALLOC_END (PKMAP_BASE-2*PAGE_SIZE)
103#else
104# define VMALLOC_END (FIXADDR_START-2*PAGE_SIZE)
105#endif
106
107#ifdef CONFIG_PHYS_ADDR_T_64BIT
108#define pte_ERROR(e) \
109 printk("%s:%d: bad pte %016Lx.\n", __FILE__, __LINE__, pte_val(e))
110#else
111#define pte_ERROR(e) \
112 printk("%s:%d: bad pte %08lx.\n", __FILE__, __LINE__, pte_val(e))
113#endif
114#define pgd_ERROR(e) \
115 printk("%s:%d: bad pgd %08lx.\n", __FILE__, __LINE__, pgd_val(e))
116
117extern void load_pgd(unsigned long pg_dir);
118
119extern pte_t invalid_pte_table[PTRS_PER_PTE];
120
121/*
122 * Empty pgd/pmd entries point to the invalid_pte_table.
123 */
124static inline int pmd_none(pmd_t pmd)
125{
126 return pmd_val(pmd) == (unsigned long) invalid_pte_table;
127}
128
129static inline int pmd_bad(pmd_t pmd)
130{
131#ifdef CONFIG_MIPS_HUGE_TLB_SUPPORT
132 /* pmd_leaf(pmd) but inline */
133 if (unlikely(pmd_val(pmd) & _PAGE_HUGE))
134 return 0;
135#endif
136
137 if (unlikely(pmd_val(pmd) & ~PAGE_MASK))
138 return 1;
139
140 return 0;
141}
142
143static inline int pmd_present(pmd_t pmd)
144{
145 return pmd_val(pmd) != (unsigned long) invalid_pte_table;
146}
147
148static inline void pmd_clear(pmd_t *pmdp)
149{
150 pmd_val(*pmdp) = ((unsigned long) invalid_pte_table);
151}
152
153#if defined(CONFIG_XPA)
154
155#define MAX_POSSIBLE_PHYSMEM_BITS 40
156#define pte_pfn(x) (((unsigned long)((x).pte_high >> PFN_PTE_SHIFT)) | (unsigned long)((x).pte_low << _PAGE_PRESENT_SHIFT))
157static inline pte_t
158pfn_pte(unsigned long pfn, pgprot_t prot)
159{
160 pte_t pte;
161
162 pte.pte_low = (pfn >> _PAGE_PRESENT_SHIFT) |
163 (pgprot_val(prot) & ~_PFNX_MASK);
164 pte.pte_high = (pfn << PFN_PTE_SHIFT) |
165 (pgprot_val(prot) & ~_PFN_MASK);
166 return pte;
167}
168
169#elif defined(CONFIG_PHYS_ADDR_T_64BIT) && defined(CONFIG_CPU_MIPS32)
170
171#define MAX_POSSIBLE_PHYSMEM_BITS 36
172#define pte_pfn(x) ((unsigned long)((x).pte_high >> 6))
173
174static inline pte_t pfn_pte(unsigned long pfn, pgprot_t prot)
175{
176 pte_t pte;
177
178 pte.pte_high = (pfn << 6) | (pgprot_val(prot) & 0x3f);
179 pte.pte_low = pgprot_val(prot);
180
181 return pte;
182}
183
184#else
185
186#define MAX_POSSIBLE_PHYSMEM_BITS 32
187#define pte_pfn(x) ((unsigned long)((x).pte >> PFN_PTE_SHIFT))
188#define pfn_pte(pfn, prot) __pte(((unsigned long long)(pfn) << PFN_PTE_SHIFT) | pgprot_val(prot))
189#define pfn_pmd(pfn, prot) __pmd(((unsigned long long)(pfn) << PFN_PTE_SHIFT) | pgprot_val(prot))
190#endif /* defined(CONFIG_PHYS_ADDR_T_64BIT) && defined(CONFIG_CPU_MIPS32) */
191
192#define pte_page(x) pfn_to_page(pte_pfn(x))
193
194/*
195 * Encode/decode swap entries and swap PTEs. Swap PTEs are all PTEs that
196 * are !pte_none() && !pte_present().
197 */
198#if defined(CONFIG_CPU_R3K_TLB)
199
200/*
201 * Format of swap PTEs:
202 *
203 * 3 3 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1
204 * 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0
205 * <----------- offset ------------> < type -> V G E 0 0 0 0 0 0 P
206 *
207 * E is the exclusive marker that is not stored in swap entries.
208 * _PAGE_PRESENT (P), _PAGE_VALID (V) and_PAGE_GLOBAL (G) have to remain
209 * unused.
210 */
211#define __swp_type(x) (((x).val >> 10) & 0x1f)
212#define __swp_offset(x) ((x).val >> 15)
213#define __swp_entry(type, offset) ((swp_entry_t) { (((type) & 0x1f) << 10) | ((offset) << 15) })
214#define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
215#define __swp_entry_to_pte(x) ((pte_t) { (x).val })
216
217/* We borrow bit 7 to store the exclusive marker in swap PTEs. */
218#define _PAGE_SWP_EXCLUSIVE (1 << 7)
219
220#else
221
222#if defined(CONFIG_XPA)
223
224/*
225 * Format of swap PTEs:
226 *
227 * 6 6 6 6 5 5 5 5 5 5 5 5 5 5 4 4 4 4 4 4 4 4 4 4 3 3 3 3 3 3 3 3
228 * 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2
229 * 0 0 0 0 0 0 E P <------------------ zeroes ------------------->
230 *
231 * 3 3 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1
232 * 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0
233 * <----------------- offset ------------------> < type -> V G 0 0
234 *
235 * E is the exclusive marker that is not stored in swap entries.
236 * _PAGE_PRESENT (P), _PAGE_VALID (V) and_PAGE_GLOBAL (G) have to remain
237 * unused.
238 */
239#define __swp_type(x) (((x).val >> 4) & 0x1f)
240#define __swp_offset(x) ((x).val >> 9)
241#define __swp_entry(type, offset) ((swp_entry_t) { (((type) & 0x1f) << 4) | ((offset) << 9) })
242#define __pte_to_swp_entry(pte) ((swp_entry_t) { (pte).pte_high })
243#define __swp_entry_to_pte(x) ((pte_t) { 0, (x).val })
244
245/*
246 * We borrow bit 57 (bit 25 in the low PTE) to store the exclusive marker in
247 * swap PTEs.
248 */
249#define _PAGE_SWP_EXCLUSIVE (1 << 25)
250
251#elif defined(CONFIG_PHYS_ADDR_T_64BIT) && defined(CONFIG_CPU_MIPS32)
252
253/*
254 * Format of swap PTEs:
255 *
256 * 6 6 6 6 5 5 5 5 5 5 5 5 5 5 4 4 4 4 4 4 4 4 4 4 3 3 3 3 3 3 3 3
257 * 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2
258 * <------------------ zeroes -------------------> E P 0 0 0 0 0 0
259 *
260 * 3 3 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1
261 * 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0
262 * <------------------- offset --------------------> < type -> V G
263 *
264 * E is the exclusive marker that is not stored in swap entries.
265 * _PAGE_PRESENT (P), _PAGE_VALID (V) and_PAGE_GLOBAL (G) have to remain
266 * unused.
267 */
268#define __swp_type(x) (((x).val >> 2) & 0x1f)
269#define __swp_offset(x) ((x).val >> 7)
270#define __swp_entry(type, offset) ((swp_entry_t) { (((type) & 0x1f) << 2) | ((offset) << 7) })
271#define __pte_to_swp_entry(pte) ((swp_entry_t) { (pte).pte_high })
272#define __swp_entry_to_pte(x) ((pte_t) { 0, (x).val })
273
274/*
275 * We borrow bit 39 (bit 7 in the low PTE) to store the exclusive marker in swap
276 * PTEs.
277 */
278#define _PAGE_SWP_EXCLUSIVE (1 << 7)
279
280#else
281/*
282 * Format of swap PTEs:
283 *
284 * 3 3 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1
285 * 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0
286 * <------------- offset --------------> < type -> 0 0 0 0 0 0 E P
287 *
288 * E is the exclusive marker that is not stored in swap entries.
289 * _PAGE_PRESENT (P), _PAGE_VALID (V) and_PAGE_GLOBAL (G) have to remain
290 * unused. The location of V and G varies.
291 */
292#define __swp_type(x) (((x).val >> 8) & 0x1f)
293#define __swp_offset(x) ((x).val >> 13)
294#define __swp_entry(type, offset) ((swp_entry_t) { ((type) << 8) | ((offset) << 13) })
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/* We borrow bit 1 to store the exclusive marker in swap PTEs. */
299#define _PAGE_SWP_EXCLUSIVE (1 << 1)
300
301#endif /* defined(CONFIG_PHYS_ADDR_T_64BIT) && defined(CONFIG_CPU_MIPS32) */
302
303#endif /* defined(CONFIG_CPU_R3K_TLB) */
304
305#endif /* _ASM_PGTABLE_32_H */