arch/mn10300/mm/pgtable.c

   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/mm.h>
  16 #include <linux/swap.h>
  17 #include <linux/smp.h>
  18 #include <linux/highmem.h>
  19 #include <linux/slab.h>
  20 #include <linux/pagemap.h>
  21 #include <linux/spinlock.h>
  22 #include <linux/quicklist.h>
  23
  24 #include <asm/system.h>
  25 #include <asm/pgtable.h>
  26 #include <asm/pgalloc.h>
  27 #include <asm/tlb.h>
  28 #include <asm/tlbflush.h>
  29
  30 void show_mem(void)
  31 {
  32         unsigned long i;
  33         int free = 0, total = 0, reserved = 0, shared = 0;
  34
  35         int cached = 0;
  36         printk(KERN_INFO "Mem-info:\n");
  37         show_free_areas();
  38         i = max_mapnr;
  39         while (i-- > 0) {
  40                 total++;
  41                 if (PageReserved(mem_map + i))
  42                         reserved++;
  43                 else if (PageSwapCache(mem_map + i))
  44                         cached++;
  45                 else if (!page_count(mem_map + i))
  46                         free++;
  47                 else
  48                         shared += page_count(mem_map + i) - 1;
  49         }
  50         printk(KERN_INFO "%d pages of RAM\n", total);
  51         printk(KERN_INFO "%d free pages\n", free);
  52         printk(KERN_INFO "%d reserved pages\n", reserved);
  53         printk(KERN_INFO "%d pages shared\n", shared);
  54         printk(KERN_INFO "%d pages swap cached\n", cached);
  55 }
  56
  57 /*
  58  * Associate a large virtual page frame with a given physical page frame
  59  * and protection flags for that frame. pfn is for the base of the page,
  60  * vaddr is what the page gets mapped to - both must be properly aligned.
  61  * The pmd must already be instantiated. Assumes PAE mode.
  62  */
  63 void set_pmd_pfn(unsigned long vaddr, unsigned long pfn, pgprot_t flags)
  64 {
  65         pgd_t *pgd;
  66         pud_t *pud;
  67         pmd_t *pmd;
  68
  69         if (vaddr & (PMD_SIZE-1)) {             /* vaddr is misaligned */
  70                 printk(KERN_ERR "set_pmd_pfn: vaddr misaligned\n");
  71                 return; /* BUG(); */
  72         }
  73         if (pfn & (PTRS_PER_PTE-1)) {           /* pfn is misaligned */
  74                 printk(KERN_ERR "set_pmd_pfn: pfn misaligned\n");
  75                 return; /* BUG(); */
  76         }
  77         pgd = swapper_pg_dir + pgd_index(vaddr);
  78         if (pgd_none(*pgd)) {
  79                 printk(KERN_ERR "set_pmd_pfn: pgd_none\n");
  80                 return; /* BUG(); */
  81         }
  82         pud = pud_offset(pgd, vaddr);
  83         pmd = pmd_offset(pud, vaddr);
  84         set_pmd(pmd, pfn_pmd(pfn, flags));
  85         /*
  86          * It's enough to flush this one mapping.
  87          * (PGE mappings get flushed as well)
  88          */
  89         __flush_tlb_one(vaddr);
  90 }
  91
  92 pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
  93 {
  94         pte_t *pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT);
  95         if (pte)
  96                 clear_page(pte);
  97         return pte;
  98 }
  99
 100 struct page *pte_alloc_one(struct mm_struct *mm, unsigned long address)
 101 {
 102         struct page *pte;
 103
 104 #ifdef CONFIG_HIGHPTE
 105         pte = alloc_pages(GFP_KERNEL|__GFP_HIGHMEM|__GFP_REPEAT, 0);
 106 #else
 107         pte = alloc_pages(GFP_KERNEL|__GFP_REPEAT, 0);
 108 #endif
 109         if (pte)
 110                 clear_highpage(pte);
 111         return pte;
 112 }
 113
 114 /*
 115  * List of all pgd's needed for non-PAE so it can invalidate entries
 116  * in both cached and uncached pgd's; not needed for PAE since the
 117  * kernel pmd is shared. If PAE were not to share the pmd a similar
 118  * tactic would be needed. This is essentially codepath-based locking
 119  * against pageattr.c; it is the unique case in which a valid change
 120  * of kernel pagetables can't be lazily synchronized by vmalloc faults.
 121  * vmalloc faults work because attached pagetables are never freed.
 122  * If the locking proves to be non-performant, a ticketing scheme with
 123  * checks at dup_mmap(), exec(), and other mmlist addition points
 124  * could be used. The locking scheme was chosen on the basis of
 125  * manfred's recommendations and having no core impact whatsoever.
 126  * -- wli
 127  */
 128 DEFINE_SPINLOCK(pgd_lock);
 129 struct page *pgd_list;
 130
 131 static inline void pgd_list_add(pgd_t *pgd)
 132 {
 133         struct page *page = virt_to_page(pgd);
 134         page->index = (unsigned long) pgd_list;
 135         if (pgd_list)
 136                 set_page_private(pgd_list, (unsigned long) &page->index);
 137         pgd_list = page;
 138         set_page_private(page, (unsigned long) &pgd_list);
 139 }
 140
 141 static inline void pgd_list_del(pgd_t *pgd)
 142 {
 143         struct page *next, **pprev, *page = virt_to_page(pgd);
 144         next = (struct page *) page->index;
 145         pprev = (struct page **) page_private(page);
 146         *pprev = next;
 147         if (next)
 148                 set_page_private(next, (unsigned long) pprev);
 149 }
 150
 151 void pgd_ctor(void *pgd)
 152 {
 153         unsigned long flags;
 154
 155         if (PTRS_PER_PMD == 1)
 156                 spin_lock_irqsave(&pgd_lock, flags);
 157
 158         memcpy((pgd_t *)pgd + USER_PTRS_PER_PGD,
 159                         swapper_pg_dir + USER_PTRS_PER_PGD,
 160                         (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
 161
 162         if (PTRS_PER_PMD > 1)
 163                 return;
 164
 165         pgd_list_add(pgd);
 166         spin_unlock_irqrestore(&pgd_lock, flags);
 167         memset(pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t));
 168 }
 169
 170 /* never called when PTRS_PER_PMD > 1 */
 171 void pgd_dtor(void *pgd)
 172 {
 173         unsigned long flags; /* can be called from interrupt context */
 174
 175         spin_lock_irqsave(&pgd_lock, flags);
 176         pgd_list_del(pgd);
 177         spin_unlock_irqrestore(&pgd_lock, flags);
 178 }
 179
 180 pgd_t *pgd_alloc(struct mm_struct *mm)
 181 {
 182         return quicklist_alloc(0, GFP_KERNEL, pgd_ctor);
 183 }
 184
 185 void pgd_free(struct mm_struct *mm, pgd_t *pgd)
 186 {
 187         quicklist_free(0, pgd_dtor, pgd);
 188 }
 189
 190 void __init pgtable_cache_init(void)
 191 {
 192 }
 193
 194 void check_pgt_cache(void)
 195 {
 196         quicklist_trim(0, pgd_dtor, 25, 16);
 197 }