1 /* MN10300 Page table management
2 *
3 * Copyright (C) 2007 Matsushita Electric Industrial Co., Ltd.
4 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
5 * Modified by David Howells (dhowells@redhat.com)
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public Licence
9 * as published by the Free Software Foundation; either version
10 * 2 of the Licence, or (at your option) any later version.
11 */
12 #include <linux/sched.h>
13 #include <linux/kernel.h>
14 #include <linux/errno.h>
15 #include <linux/gfp.h>
16 #include <linux/mm.h>
17 #include <linux/swap.h>
18 #include <linux/smp.h>
19 #include <linux/highmem.h>
20 #include <linux/pagemap.h>
21 #include <linux/spinlock.h>
22 #include <linux/quicklist.h>
23
24 #include <asm/pgtable.h>
25 #include <asm/pgalloc.h>
26 #include <asm/tlb.h>
27 #include <asm/tlbflush.h>
28
29 /*
30 * Associate a large virtual page frame with a given physical page frame
31 * and protection flags for that frame. pfn is for the base of the page,
32 * vaddr is what the page gets mapped to - both must be properly aligned.
33 * The pmd must already be instantiated. Assumes PAE mode.
34 */
set_pmd_pfn(unsigned long vaddr,unsigned long pfn,pgprot_t flags)35 void set_pmd_pfn(unsigned long vaddr, unsigned long pfn, pgprot_t flags)
36 {
37 pgd_t *pgd;
38 pud_t *pud;
39 pmd_t *pmd;
40
41 if (vaddr & (PMD_SIZE-1)) { /* vaddr is misaligned */
42 printk(KERN_ERR "set_pmd_pfn: vaddr misaligned\n");
43 return; /* BUG(); */
44 }
45 if (pfn & (PTRS_PER_PTE-1)) { /* pfn is misaligned */
46 printk(KERN_ERR "set_pmd_pfn: pfn misaligned\n");
47 return; /* BUG(); */
48 }
49 pgd = swapper_pg_dir + pgd_index(vaddr);
50 if (pgd_none(*pgd)) {
51 printk(KERN_ERR "set_pmd_pfn: pgd_none\n");
52 return; /* BUG(); */
53 }
54 pud = pud_offset(pgd, vaddr);
55 pmd = pmd_offset(pud, vaddr);
56 set_pmd(pmd, pfn_pmd(pfn, flags));
57 /*
58 * It's enough to flush this one mapping.
59 * (PGE mappings get flushed as well)
60 */
61 local_flush_tlb_one(vaddr);
62 }
63
pte_alloc_one_kernel(struct mm_struct * mm,unsigned long address)64 pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
65 {
66 pte_t *pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT);
67 if (pte)
68 clear_page(pte);
69 return pte;
70 }
71
pte_alloc_one(struct mm_struct * mm,unsigned long address)72 struct page *pte_alloc_one(struct mm_struct *mm, unsigned long address)
73 {
74 struct page *pte;
75
76 #ifdef CONFIG_HIGHPTE
77 pte = alloc_pages(GFP_KERNEL|__GFP_HIGHMEM|__GFP_REPEAT, 0);
78 #else
79 pte = alloc_pages(GFP_KERNEL|__GFP_REPEAT, 0);
80 #endif
81 if (pte)
82 clear_highpage(pte);
83 return pte;
84 }
85
86 /*
87 * List of all pgd's needed for non-PAE so it can invalidate entries
88 * in both cached and uncached pgd's; not needed for PAE since the
89 * kernel pmd is shared. If PAE were not to share the pmd a similar
90 * tactic would be needed. This is essentially codepath-based locking
91 * against pageattr.c; it is the unique case in which a valid change
92 * of kernel pagetables can't be lazily synchronized by vmalloc faults.
93 * vmalloc faults work because attached pagetables are never freed.
94 * If the locking proves to be non-performant, a ticketing scheme with
95 * checks at dup_mmap(), exec(), and other mmlist addition points
96 * could be used. The locking scheme was chosen on the basis of
97 * manfred's recommendations and having no core impact whatsoever.
98 * -- wli
99 */
100 DEFINE_SPINLOCK(pgd_lock);
101 struct page *pgd_list;
102
pgd_list_add(pgd_t * pgd)103 static inline void pgd_list_add(pgd_t *pgd)
104 {
105 struct page *page = virt_to_page(pgd);
106 page->index = (unsigned long) pgd_list;
107 if (pgd_list)
108 set_page_private(pgd_list, (unsigned long) &page->index);
109 pgd_list = page;
110 set_page_private(page, (unsigned long) &pgd_list);
111 }
112
pgd_list_del(pgd_t * pgd)113 static inline void pgd_list_del(pgd_t *pgd)
114 {
115 struct page *next, **pprev, *page = virt_to_page(pgd);
116 next = (struct page *) page->index;
117 pprev = (struct page **) page_private(page);
118 *pprev = next;
119 if (next)
120 set_page_private(next, (unsigned long) pprev);
121 }
122
pgd_ctor(void * pgd)123 void pgd_ctor(void *pgd)
124 {
125 unsigned long flags;
126
127 if (PTRS_PER_PMD == 1)
128 spin_lock_irqsave(&pgd_lock, flags);
129
130 memcpy((pgd_t *)pgd + USER_PTRS_PER_PGD,
131 swapper_pg_dir + USER_PTRS_PER_PGD,
132 (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
133
134 if (PTRS_PER_PMD > 1)
135 return;
136
137 pgd_list_add(pgd);
138 spin_unlock_irqrestore(&pgd_lock, flags);
139 memset(pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t));
140 }
141
142 /* never called when PTRS_PER_PMD > 1 */
pgd_dtor(void * pgd)143 void pgd_dtor(void *pgd)
144 {
145 unsigned long flags; /* can be called from interrupt context */
146
147 spin_lock_irqsave(&pgd_lock, flags);
148 pgd_list_del(pgd);
149 spin_unlock_irqrestore(&pgd_lock, flags);
150 }
151
pgd_alloc(struct mm_struct * mm)152 pgd_t *pgd_alloc(struct mm_struct *mm)
153 {
154 return quicklist_alloc(0, GFP_KERNEL, pgd_ctor);
155 }
156
pgd_free(struct mm_struct * mm,pgd_t * pgd)157 void pgd_free(struct mm_struct *mm, pgd_t *pgd)
158 {
159 quicklist_free(0, pgd_dtor, pgd);
160 }
161
pgtable_cache_init(void)162 void __init pgtable_cache_init(void)
163 {
164 }
165
check_pgt_cache(void)166 void check_pgt_cache(void)
167 {
168 quicklist_trim(0, pgd_dtor, 25, 16);
169 }
170