arch/i386/mm/pgtable.c

   1 /*
   2  *  linux/arch/i386/mm/pgtable.c
   3  */
   4
   5 #include <linux/config.h>
   6 #include <linux/sched.h>
   7 #include <linux/kernel.h>
   8 #include <linux/errno.h>
   9 #include <linux/mm.h>
  10 #include <linux/swap.h>
  11 #include <linux/smp.h>
  12 #include <linux/highmem.h>
  13 #include <linux/slab.h>
  14 #include <linux/pagemap.h>
  15 #include <linux/spinlock.h>
  16
  17 #include <asm/system.h>
  18 #include <asm/pgtable.h>
  19 #include <asm/pgalloc.h>
  20 #include <asm/fixmap.h>
  21 #include <asm/e820.h>
  22 #include <asm/tlb.h>
  23 #include <asm/tlbflush.h>
  24
  25 void show_mem(void)
  26 {
  27         int total = 0, reserved = 0;
  28         int shared = 0, cached = 0;
  29         int highmem = 0;
  30         struct page *page;
  31         pg_data_t *pgdat;
  32         unsigned long i;
  33
  34         printk("Mem-info:\n");
  35         show_free_areas();
  36         printk("Free swap:       %6ldkB\n", nr_swap_pages<<(PAGE_SHIFT-10));
  37         for_each_pgdat(pgdat) {
  38                 for (i = 0; i < pgdat->node_spanned_pages; ++i) {
  39                         page = pgdat->node_mem_map + i;
  40                         total++;
  41                         if (PageHighMem(page))
  42                                 highmem++;
  43                         if (PageReserved(page))
  44                                 reserved++;
  45                         else if (PageSwapCache(page))
  46                                 cached++;
  47                         else if (page_count(page))
  48                                 shared += page_count(page) - 1;
  49                 }
  50         }
  51         printk("%d pages of RAM\n", total);
  52         printk("%d pages of HIGHMEM\n",highmem);
  53         printk("%d reserved pages\n",reserved);
  54         printk("%d pages shared\n",shared);
  55         printk("%d pages swap cached\n",cached);
  56 }
  57
  58 /*
  59  * Associate a virtual page frame with a given physical page frame
  60  * and protection flags for that frame.
  61  */
  62 static void set_pte_pfn(unsigned long vaddr, unsigned long pfn, pgprot_t flags)
  63 {
  64         pgd_t *pgd;
  65         pud_t *pud;
  66         pmd_t *pmd;
  67         pte_t *pte;
  68
  69         pgd = swapper_pg_dir + pgd_index(vaddr);
  70         if (pgd_none(*pgd)) {
  71                 BUG();
  72                 return;
  73         }
  74         pud = pud_offset(pgd, vaddr);
  75         if (pud_none(*pud)) {
  76                 BUG();
  77                 return;
  78         }
  79         pmd = pmd_offset(pud, vaddr);
  80         if (pmd_none(*pmd)) {
  81                 BUG();
  82                 return;
  83         }
  84         pte = pte_offset_kernel(pmd, vaddr);
  85         /* <pfn,flags> stored as-is, to permit clearing entries */
  86         set_pte(pte, pfn_pte(pfn, flags));
  87
  88         /*
  89          * It's enough to flush this one mapping.
  90          * (PGE mappings get flushed as well)
  91          */
  92         __flush_tlb_one(vaddr);
  93 }
  94
  95 /*
  96  * Associate a large virtual page frame with a given physical page frame
  97  * and protection flags for that frame. pfn is for the base of the page,
  98  * vaddr is what the page gets mapped to - both must be properly aligned.
  99  * The pmd must already be instantiated. Assumes PAE mode.
 100  */
 101 void set_pmd_pfn(unsigned long vaddr, unsigned long pfn, pgprot_t flags)
 102 {
 103         pgd_t *pgd;
 104         pud_t *pud;
 105         pmd_t *pmd;
 106
 107         if (vaddr & (PMD_SIZE-1)) {             /* vaddr is misaligned */
 108                 printk ("set_pmd_pfn: vaddr misaligned\n");
 109                 return; /* BUG(); */
 110         }
 111         if (pfn & (PTRS_PER_PTE-1)) {           /* pfn is misaligned */
 112                 printk ("set_pmd_pfn: pfn misaligned\n");
 113                 return; /* BUG(); */
 114         }
 115         pgd = swapper_pg_dir + pgd_index(vaddr);
 116         if (pgd_none(*pgd)) {
 117                 printk ("set_pmd_pfn: pgd_none\n");
 118                 return; /* BUG(); */
 119         }
 120         pud = pud_offset(pgd, vaddr);
 121         pmd = pmd_offset(pud, vaddr);
 122         set_pmd(pmd, pfn_pmd(pfn, flags));
 123         /*
 124          * It's enough to flush this one mapping.
 125          * (PGE mappings get flushed as well)
 126          */
 127         __flush_tlb_one(vaddr);
 128 }
 129
 130 void __set_fixmap (enum fixed_addresses idx, unsigned long phys, pgprot_t flags)
 131 {
 132         unsigned long address = __fix_to_virt(idx);
 133
 134         if (idx >= __end_of_fixed_addresses) {
 135                 BUG();
 136                 return;
 137         }
 138         set_pte_pfn(address, phys >> PAGE_SHIFT, flags);
 139 }
 140
 141 pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
 142 {
 143         return (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
 144 }
 145
 146 struct page *pte_alloc_one(struct mm_struct *mm, unsigned long address)
 147 {
 148         struct page *pte;
 149
 150 #ifdef CONFIG_HIGHPTE
 151         pte = alloc_pages(GFP_KERNEL|__GFP_HIGHMEM|__GFP_REPEAT|__GFP_ZERO, 0);
 152 #else
 153         pte = alloc_pages(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO, 0);
 154 #endif
 155         return pte;
 156 }
 157
 158 void pmd_ctor(void *pmd, kmem_cache_t *cache, unsigned long flags)
 159 {
 160         memset(pmd, 0, PTRS_PER_PMD*sizeof(pmd_t));
 161 }
 162
 163 /*
 164  * List of all pgd's needed for non-PAE so it can invalidate entries
 165  * in both cached and uncached pgd's; not needed for PAE since the
 166  * kernel pmd is shared. If PAE were not to share the pmd a similar
 167  * tactic would be needed. This is essentially codepath-based locking
 168  * against pageattr.c; it is the unique case in which a valid change
 169  * of kernel pagetables can't be lazily synchronized by vmalloc faults.
 170  * vmalloc faults work because attached pagetables are never freed.
 171  * The locking scheme was chosen on the basis of manfred's
 172  * recommendations and having no core impact whatsoever.
 173  * -- wli
 174  */
 175 DEFINE_SPINLOCK(pgd_lock);
 176 struct page *pgd_list;
 177
 178 static inline void pgd_list_add(pgd_t *pgd)
 179 {
 180         struct page *page = virt_to_page(pgd);
 181         page->index = (unsigned long)pgd_list;
 182         if (pgd_list)
 183                 pgd_list->private = (unsigned long)&page->index;
 184         pgd_list = page;
 185         page->private = (unsigned long)&pgd_list;
 186 }
 187
 188 static inline void pgd_list_del(pgd_t *pgd)
 189 {
 190         struct page *next, **pprev, *page = virt_to_page(pgd);
 191         next = (struct page *)page->index;
 192         pprev = (struct page **)page->private;
 193         *pprev = next;
 194         if (next)
 195                 next->private = (unsigned long)pprev;
 196 }
 197
 198 void pgd_ctor(void *pgd, kmem_cache_t *cache, unsigned long unused)
 199 {
 200         unsigned long flags;
 201
 202         if (PTRS_PER_PMD == 1)
 203                 spin_lock_irqsave(&pgd_lock, flags);
 204
 205         memcpy((pgd_t *)pgd + USER_PTRS_PER_PGD,
 206                         swapper_pg_dir + USER_PTRS_PER_PGD,
 207                         (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
 208
 209         if (PTRS_PER_PMD > 1)
 210                 return;
 211
 212         pgd_list_add(pgd);
 213         spin_unlock_irqrestore(&pgd_lock, flags);
 214         memset(pgd, 0, USER_PTRS_PER_PGD*sizeof(pgd_t));
 215 }
 216
 217 /* never called when PTRS_PER_PMD > 1 */
 218 void pgd_dtor(void *pgd, kmem_cache_t *cache, unsigned long unused)
 219 {
 220         unsigned long flags; /* can be called from interrupt context */
 221
 222         spin_lock_irqsave(&pgd_lock, flags);
 223         pgd_list_del(pgd);
 224         spin_unlock_irqrestore(&pgd_lock, flags);
 225 }
 226
 227 pgd_t *pgd_alloc(struct mm_struct *mm)
 228 {
 229         int i;
 230         pgd_t *pgd = kmem_cache_alloc(pgd_cache, GFP_KERNEL);
 231
 232         if (PTRS_PER_PMD == 1 || !pgd)
 233                 return pgd;
 234
 235         for (i = 0; i < USER_PTRS_PER_PGD; ++i) {
 236                 pmd_t *pmd = kmem_cache_alloc(pmd_cache, GFP_KERNEL);
 237                 if (!pmd)
 238                         goto out_oom;
 239                 set_pgd(&pgd[i], __pgd(1 + __pa(pmd)));
 240         }
 241         return pgd;
 242
 243 out_oom:
 244         for (i--; i >= 0; i--)
 245                 kmem_cache_free(pmd_cache, (void *)__va(pgd_val(pgd[i])-1));
 246         kmem_cache_free(pgd_cache, pgd);
 247         return NULL;
 248 }
 249
 250 void pgd_free(pgd_t *pgd)
 251 {
 252         int i;
 253
 254         /* in the PAE case user pgd entries are overwritten before usage */
 255         if (PTRS_PER_PMD > 1)
 256                 for (i = 0; i < USER_PTRS_PER_PGD; ++i)
 257                         kmem_cache_free(pmd_cache, (void *)__va(pgd_val(pgd[i])-1));
 258         /* in the non-PAE case, clear_page_range() clears user pgd entries */
 259         kmem_cache_free(pgd_cache, pgd);
 260 }