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         struct page_state ps;
  34         unsigned long flags;
  35
  36         printk(KERN_INFO "Mem-info:\n");
  37         show_free_areas();
  38         printk(KERN_INFO "Free swap:       %6ldkB\n", nr_swap_pages<<(PAGE_SHIFT-10));
  39         for_each_pgdat(pgdat) {
  40                 pgdat_resize_lock(pgdat, &flags);
  41                 for (i = 0; i < pgdat->node_spanned_pages; ++i) {
  42                         page = pgdat_page_nr(pgdat, i);
  43                         total++;
  44                         if (PageHighMem(page))
  45                                 highmem++;
  46                         if (PageReserved(page))
  47                                 reserved++;
  48                         else if (PageSwapCache(page))
  49                                 cached++;
  50                         else if (page_count(page))
  51                                 shared += page_count(page) - 1;
  52                 }
  53                 pgdat_resize_unlock(pgdat, &flags);
  54         }
  55         printk(KERN_INFO "%d pages of RAM\n", total);
  56         printk(KERN_INFO "%d pages of HIGHMEM\n", highmem);
  57         printk(KERN_INFO "%d reserved pages\n", reserved);
  58         printk(KERN_INFO "%d pages shared\n", shared);
  59         printk(KERN_INFO "%d pages swap cached\n", cached);
  60
  61         get_page_state(&ps);
  62         printk(KERN_INFO "%lu pages dirty\n", ps.nr_dirty);
  63         printk(KERN_INFO "%lu pages writeback\n", ps.nr_writeback);
  64         printk(KERN_INFO "%lu pages mapped\n", ps.nr_mapped);
  65         printk(KERN_INFO "%lu pages slab\n", ps.nr_slab);
  66         printk(KERN_INFO "%lu pages pagetables\n", ps.nr_page_table_pages);
  67 }
  68
  69 /*
  70  * Associate a virtual page frame with a given physical page frame
  71  * and protection flags for that frame.
  72  */
  73 static void set_pte_pfn(unsigned long vaddr, unsigned long pfn, pgprot_t flags)
  74 {
  75         pgd_t *pgd;
  76         pud_t *pud;
  77         pmd_t *pmd;
  78         pte_t *pte;
  79
  80         pgd = swapper_pg_dir + pgd_index(vaddr);
  81         if (pgd_none(*pgd)) {
  82                 BUG();
  83                 return;
  84         }
  85         pud = pud_offset(pgd, vaddr);
  86         if (pud_none(*pud)) {
  87                 BUG();
  88                 return;
  89         }
  90         pmd = pmd_offset(pud, vaddr);
  91         if (pmd_none(*pmd)) {
  92                 BUG();
  93                 return;
  94         }
  95         pte = pte_offset_kernel(pmd, vaddr);
  96         /* <pfn,flags> stored as-is, to permit clearing entries */
  97         set_pte(pte, pfn_pte(pfn, flags));
  98
  99         /*
 100          * It's enough to flush this one mapping.
 101          * (PGE mappings get flushed as well)
 102          */
 103         __flush_tlb_one(vaddr);
 104 }
 105
 106 /*
 107  * Associate a large virtual page frame with a given physical page frame
 108  * and protection flags for that frame. pfn is for the base of the page,
 109  * vaddr is what the page gets mapped to - both must be properly aligned.
 110  * The pmd must already be instantiated. Assumes PAE mode.
 111  */
 112 void set_pmd_pfn(unsigned long vaddr, unsigned long pfn, pgprot_t flags)
 113 {
 114         pgd_t *pgd;
 115         pud_t *pud;
 116         pmd_t *pmd;
 117
 118         if (vaddr & (PMD_SIZE-1)) {             /* vaddr is misaligned */
 119                 printk(KERN_WARNING "set_pmd_pfn: vaddr misaligned\n");
 120                 return; /* BUG(); */
 121         }
 122         if (pfn & (PTRS_PER_PTE-1)) {           /* pfn is misaligned */
 123                 printk(KERN_WARNING "set_pmd_pfn: pfn misaligned\n");
 124                 return; /* BUG(); */
 125         }
 126         pgd = swapper_pg_dir + pgd_index(vaddr);
 127         if (pgd_none(*pgd)) {
 128                 printk(KERN_WARNING "set_pmd_pfn: pgd_none\n");
 129                 return; /* BUG(); */
 130         }
 131         pud = pud_offset(pgd, vaddr);
 132         pmd = pmd_offset(pud, vaddr);
 133         set_pmd(pmd, pfn_pmd(pfn, flags));
 134         /*
 135          * It's enough to flush this one mapping.
 136          * (PGE mappings get flushed as well)
 137          */
 138         __flush_tlb_one(vaddr);
 139 }
 140
 141 void __set_fixmap (enum fixed_addresses idx, unsigned long phys, pgprot_t flags)
 142 {
 143         unsigned long address = __fix_to_virt(idx);
 144
 145         if (idx >= __end_of_fixed_addresses) {
 146                 BUG();
 147                 return;
 148         }
 149         set_pte_pfn(address, phys >> PAGE_SHIFT, flags);
 150 }
 151
 152 pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
 153 {
 154         return (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
 155 }
 156
 157 struct page *pte_alloc_one(struct mm_struct *mm, unsigned long address)
 158 {
 159         struct page *pte;
 160
 161 #ifdef CONFIG_HIGHPTE
 162         pte = alloc_pages(GFP_KERNEL|__GFP_HIGHMEM|__GFP_REPEAT|__GFP_ZERO, 0);
 163 #else
 164         pte = alloc_pages(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO, 0);
 165 #endif
 166         return pte;
 167 }
 168
 169 void pmd_ctor(void *pmd, kmem_cache_t *cache, unsigned long flags)
 170 {
 171         memset(pmd, 0, PTRS_PER_PMD*sizeof(pmd_t));
 172 }
 173
 174 /*
 175  * List of all pgd's needed for non-PAE so it can invalidate entries
 176  * in both cached and uncached pgd's; not needed for PAE since the
 177  * kernel pmd is shared. If PAE were not to share the pmd a similar
 178  * tactic would be needed. This is essentially codepath-based locking
 179  * against pageattr.c; it is the unique case in which a valid change
 180  * of kernel pagetables can't be lazily synchronized by vmalloc faults.
 181  * vmalloc faults work because attached pagetables are never freed.
 182  * The locking scheme was chosen on the basis of manfred's
 183  * recommendations and having no core impact whatsoever.
 184  * -- wli
 185  */
 186 DEFINE_SPINLOCK(pgd_lock);
 187 struct page *pgd_list;
 188
 189 static inline void pgd_list_add(pgd_t *pgd)
 190 {
 191         struct page *page = virt_to_page(pgd);
 192         page->index = (unsigned long)pgd_list;
 193         if (pgd_list)
 194                 set_page_private(pgd_list, (unsigned long)&page->index);
 195         pgd_list = page;
 196         set_page_private(page, (unsigned long)&pgd_list);
 197 }
 198
 199 static inline void pgd_list_del(pgd_t *pgd)
 200 {
 201         struct page *next, **pprev, *page = virt_to_page(pgd);
 202         next = (struct page *)page->index;
 203         pprev = (struct page **)page_private(page);
 204         *pprev = next;
 205         if (next)
 206                 set_page_private(next, (unsigned long)pprev);
 207 }
 208
 209 void pgd_ctor(void *pgd, kmem_cache_t *cache, unsigned long unused)
 210 {
 211         unsigned long flags;
 212
 213         if (PTRS_PER_PMD == 1) {
 214                 memset(pgd, 0, USER_PTRS_PER_PGD*sizeof(pgd_t));
 215                 spin_lock_irqsave(&pgd_lock, flags);
 216         }
 217
 218         clone_pgd_range((pgd_t *)pgd + USER_PTRS_PER_PGD,
 219                         swapper_pg_dir + USER_PTRS_PER_PGD,
 220                         KERNEL_PGD_PTRS);
 221         if (PTRS_PER_PMD > 1)
 222                 return;
 223
 224         pgd_list_add(pgd);
 225         spin_unlock_irqrestore(&pgd_lock, flags);
 226 }
 227
 228 /* never called when PTRS_PER_PMD > 1 */
 229 void pgd_dtor(void *pgd, kmem_cache_t *cache, unsigned long unused)
 230 {
 231         unsigned long flags; /* can be called from interrupt context */
 232
 233         spin_lock_irqsave(&pgd_lock, flags);
 234         pgd_list_del(pgd);
 235         spin_unlock_irqrestore(&pgd_lock, flags);
 236 }
 237
 238 pgd_t *pgd_alloc(struct mm_struct *mm)
 239 {
 240         int i;
 241         pgd_t *pgd = kmem_cache_alloc(pgd_cache, GFP_KERNEL);
 242
 243         if (PTRS_PER_PMD == 1 || !pgd)
 244                 return pgd;
 245
 246         for (i = 0; i < USER_PTRS_PER_PGD; ++i) {
 247                 pmd_t *pmd = kmem_cache_alloc(pmd_cache, GFP_KERNEL);
 248                 if (!pmd)
 249                         goto out_oom;
 250                 set_pgd(&pgd[i], __pgd(1 + __pa(pmd)));
 251         }
 252         return pgd;
 253
 254 out_oom:
 255         for (i--; i >= 0; i--)
 256                 kmem_cache_free(pmd_cache, (void *)__va(pgd_val(pgd[i])-1));
 257         kmem_cache_free(pgd_cache, pgd);
 258         return NULL;
 259 }
 260
 261 void pgd_free(pgd_t *pgd)
 262 {
 263         int i;
 264
 265         /* in the PAE case user pgd entries are overwritten before usage */
 266         if (PTRS_PER_PMD > 1)
 267                 for (i = 0; i < USER_PTRS_PER_PGD; ++i)
 268                         kmem_cache_free(pmd_cache, (void *)__va(pgd_val(pgd[i])-1));
 269         /* in the non-PAE case, free_pgtables() clears user pgd entries */
 270         kmem_cache_free(pgd_cache, pgd);
 271 }