git.oblomov.eu Git - linux-2.6/blob - arch/i386/mm/pgtable.c

   1 /*
   2  *  linux/arch/i386/mm/pgtable.c
   3  */
   4
   5 #include <linux/sched.h>
   6 #include <linux/kernel.h>
   7 #include <linux/errno.h>
   8 #include <linux/mm.h>
   9 #include <linux/swap.h>
  10 #include <linux/smp.h>
  11 #include <linux/highmem.h>
  12 #include <linux/slab.h>
  13 #include <linux/pagemap.h>
  14 #include <linux/spinlock.h>
  15 #include <linux/module.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         unsigned long flags;
  34
  35         printk(KERN_INFO "Mem-info:\n");
  36         show_free_areas();
  37         printk(KERN_INFO "Free swap:       %6ldkB\n", nr_swap_pages<<(PAGE_SHIFT-10));
  38         for_each_online_pgdat(pgdat) {
  39                 pgdat_resize_lock(pgdat, &flags);
  40                 for (i = 0; i < pgdat->node_spanned_pages; ++i) {
  41                         page = pgdat_page_nr(pgdat, i);
  42                         total++;
  43                         if (PageHighMem(page))
  44                                 highmem++;
  45                         if (PageReserved(page))
  46                                 reserved++;
  47                         else if (PageSwapCache(page))
  48                                 cached++;
  49                         else if (page_count(page))
  50                                 shared += page_count(page) - 1;
  51                 }
  52                 pgdat_resize_unlock(pgdat, &flags);
  53         }
  54         printk(KERN_INFO "%d pages of RAM\n", total);
  55         printk(KERN_INFO "%d pages of HIGHMEM\n", highmem);
  56         printk(KERN_INFO "%d reserved pages\n", reserved);
  57         printk(KERN_INFO "%d pages shared\n", shared);
  58         printk(KERN_INFO "%d pages swap cached\n", cached);
  59
  60         printk(KERN_INFO "%lu pages dirty\n", global_page_state(NR_FILE_DIRTY));
  61         printk(KERN_INFO "%lu pages writeback\n",
  62                                         global_page_state(NR_WRITEBACK));
  63         printk(KERN_INFO "%lu pages mapped\n", global_page_state(NR_FILE_MAPPED));
  64         printk(KERN_INFO "%lu pages slab\n",
  65                 global_page_state(NR_SLAB_RECLAIMABLE) +
  66                 global_page_state(NR_SLAB_UNRECLAIMABLE));
  67         printk(KERN_INFO "%lu pages pagetables\n",
  68                                         global_page_state(NR_PAGETABLE));
  69 }
  70
  71 /*
  72  * Associate a virtual page frame with a given physical page frame
  73  * and protection flags for that frame.
  74  */
  75 static void set_pte_pfn(unsigned long vaddr, unsigned long pfn, pgprot_t flags)
  76 {
  77         pgd_t *pgd;
  78         pud_t *pud;
  79         pmd_t *pmd;
  80         pte_t *pte;
  81
  82         pgd = swapper_pg_dir + pgd_index(vaddr);
  83         if (pgd_none(*pgd)) {
  84                 BUG();
  85                 return;
  86         }
  87         pud = pud_offset(pgd, vaddr);
  88         if (pud_none(*pud)) {
  89                 BUG();
  90                 return;
  91         }
  92         pmd = pmd_offset(pud, vaddr);
  93         if (pmd_none(*pmd)) {
  94                 BUG();
  95                 return;
  96         }
  97         pte = pte_offset_kernel(pmd, vaddr);
  98         if (pgprot_val(flags))
  99                 /* <pfn,flags> stored as-is, to permit clearing entries */
 100                 set_pte(pte, pfn_pte(pfn, flags));
 101         else
 102                 pte_clear(&init_mm, vaddr, pte);
 103
 104         /*
 105          * It's enough to flush this one mapping.
 106          * (PGE mappings get flushed as well)
 107          */
 108         __flush_tlb_one(vaddr);
 109 }
 110
 111 /*
 112  * Associate a large virtual page frame with a given physical page frame
 113  * and protection flags for that frame. pfn is for the base of the page,
 114  * vaddr is what the page gets mapped to - both must be properly aligned.
 115  * The pmd must already be instantiated. Assumes PAE mode.
 116  */
 117 void set_pmd_pfn(unsigned long vaddr, unsigned long pfn, pgprot_t flags)
 118 {
 119         pgd_t *pgd;
 120         pud_t *pud;
 121         pmd_t *pmd;
 122
 123         if (vaddr & (PMD_SIZE-1)) {             /* vaddr is misaligned */
 124                 printk(KERN_WARNING "set_pmd_pfn: vaddr misaligned\n");
 125                 return; /* BUG(); */
 126         }
 127         if (pfn & (PTRS_PER_PTE-1)) {           /* pfn is misaligned */
 128                 printk(KERN_WARNING "set_pmd_pfn: pfn misaligned\n");
 129                 return; /* BUG(); */
 130         }
 131         pgd = swapper_pg_dir + pgd_index(vaddr);
 132         if (pgd_none(*pgd)) {
 133                 printk(KERN_WARNING "set_pmd_pfn: pgd_none\n");
 134                 return; /* BUG(); */
 135         }
 136         pud = pud_offset(pgd, vaddr);
 137         pmd = pmd_offset(pud, vaddr);
 138         set_pmd(pmd, pfn_pmd(pfn, flags));
 139         /*
 140          * It's enough to flush this one mapping.
 141          * (PGE mappings get flushed as well)
 142          */
 143         __flush_tlb_one(vaddr);
 144 }
 145
 146 static int fixmaps;
 147 #ifndef CONFIG_COMPAT_VDSO
 148 unsigned long __FIXADDR_TOP = 0xfffff000;
 149 EXPORT_SYMBOL(__FIXADDR_TOP);
 150 #endif
 151
 152 void __set_fixmap (enum fixed_addresses idx, unsigned long phys, pgprot_t flags)
 153 {
 154         unsigned long address = __fix_to_virt(idx);
 155
 156         if (idx >= __end_of_fixed_addresses) {
 157                 BUG();
 158                 return;
 159         }
 160         set_pte_pfn(address, phys >> PAGE_SHIFT, flags);
 161         fixmaps++;
 162 }
 163
 164 /**
 165  * reserve_top_address - reserves a hole in the top of kernel address space
 166  * @reserve - size of hole to reserve
 167  *
 168  * Can be used to relocate the fixmap area and poke a hole in the top
 169  * of kernel address space to make room for a hypervisor.
 170  */
 171 void reserve_top_address(unsigned long reserve)
 172 {
 173         BUG_ON(fixmaps > 0);
 174         printk(KERN_INFO "Reserving virtual address space above 0x%08x\n",
 175                (int)-reserve);
 176 #ifdef CONFIG_COMPAT_VDSO
 177         BUG_ON(reserve != 0);
 178 #else
 179         __FIXADDR_TOP = -reserve - PAGE_SIZE;
 180         __VMALLOC_RESERVE += reserve;
 181 #endif
 182 }
 183
 184 pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
 185 {
 186         return (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
 187 }
 188
 189 struct page *pte_alloc_one(struct mm_struct *mm, unsigned long address)
 190 {
 191         struct page *pte;
 192
 193 #ifdef CONFIG_HIGHPTE
 194         pte = alloc_pages(GFP_KERNEL|__GFP_HIGHMEM|__GFP_REPEAT|__GFP_ZERO, 0);
 195 #else
 196         pte = alloc_pages(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO, 0);
 197 #endif
 198         return pte;
 199 }
 200
 201 void pmd_ctor(void *pmd, struct kmem_cache *cache, unsigned long flags)
 202 {
 203         memset(pmd, 0, PTRS_PER_PMD*sizeof(pmd_t));
 204 }
 205
 206 /*
 207  * List of all pgd's needed for non-PAE so it can invalidate entries
 208  * in both cached and uncached pgd's; not needed for PAE since the
 209  * kernel pmd is shared. If PAE were not to share the pmd a similar
 210  * tactic would be needed. This is essentially codepath-based locking
 211  * against pageattr.c; it is the unique case in which a valid change
 212  * of kernel pagetables can't be lazily synchronized by vmalloc faults.
 213  * vmalloc faults work because attached pagetables are never freed.
 214  * The locking scheme was chosen on the basis of manfred's
 215  * recommendations and having no core impact whatsoever.
 216  * -- wli
 217  */
 218 DEFINE_SPINLOCK(pgd_lock);
 219 struct page *pgd_list;
 220
 221 static inline void pgd_list_add(pgd_t *pgd)
 222 {
 223         struct page *page = virt_to_page(pgd);
 224         page->index = (unsigned long)pgd_list;
 225         if (pgd_list)
 226                 set_page_private(pgd_list, (unsigned long)&page->index);
 227         pgd_list = page;
 228         set_page_private(page, (unsigned long)&pgd_list);
 229 }
 230
 231 static inline void pgd_list_del(pgd_t *pgd)
 232 {
 233         struct page *next, **pprev, *page = virt_to_page(pgd);
 234         next = (struct page *)page->index;
 235         pprev = (struct page **)page_private(page);
 236         *pprev = next;
 237         if (next)
 238                 set_page_private(next, (unsigned long)pprev);
 239 }
 240
 241 void pgd_ctor(void *pgd, struct kmem_cache *cache, unsigned long unused)
 242 {
 243         unsigned long flags;
 244
 245         if (PTRS_PER_PMD == 1) {
 246                 memset(pgd, 0, USER_PTRS_PER_PGD*sizeof(pgd_t));
 247                 spin_lock_irqsave(&pgd_lock, flags);
 248         }
 249
 250         clone_pgd_range((pgd_t *)pgd + USER_PTRS_PER_PGD,
 251                         swapper_pg_dir + USER_PTRS_PER_PGD,
 252                         KERNEL_PGD_PTRS);
 253
 254         if (PTRS_PER_PMD > 1)
 255                 return;
 256
 257         /* must happen under lock */
 258         paravirt_alloc_pd_clone(__pa(pgd) >> PAGE_SHIFT,
 259                         __pa(swapper_pg_dir) >> PAGE_SHIFT,
 260                         USER_PTRS_PER_PGD, PTRS_PER_PGD - USER_PTRS_PER_PGD);
 261
 262         pgd_list_add(pgd);
 263         spin_unlock_irqrestore(&pgd_lock, flags);
 264 }
 265
 266 /* never called when PTRS_PER_PMD > 1 */
 267 void pgd_dtor(void *pgd, struct kmem_cache *cache, unsigned long unused)
 268 {
 269         unsigned long flags; /* can be called from interrupt context */
 270
 271         paravirt_release_pd(__pa(pgd) >> PAGE_SHIFT);
 272         spin_lock_irqsave(&pgd_lock, flags);
 273         pgd_list_del(pgd);
 274         spin_unlock_irqrestore(&pgd_lock, flags);
 275 }
 276
 277 pgd_t *pgd_alloc(struct mm_struct *mm)
 278 {
 279         int i;
 280         pgd_t *pgd = kmem_cache_alloc(pgd_cache, GFP_KERNEL);
 281
 282         if (PTRS_PER_PMD == 1 || !pgd)
 283                 return pgd;
 284
 285         for (i = 0; i < USER_PTRS_PER_PGD; ++i) {
 286                 pmd_t *pmd = kmem_cache_alloc(pmd_cache, GFP_KERNEL);
 287                 if (!pmd)
 288                         goto out_oom;
 289                 paravirt_alloc_pd(__pa(pmd) >> PAGE_SHIFT);
 290                 set_pgd(&pgd[i], __pgd(1 + __pa(pmd)));
 291         }
 292         return pgd;
 293
 294 out_oom:
 295         for (i--; i >= 0; i--) {
 296                 pgd_t pgdent = pgd[i];
 297                 void* pmd = (void *)__va(pgd_val(pgdent)-1);
 298                 paravirt_release_pd(__pa(pmd) >> PAGE_SHIFT);
 299                 kmem_cache_free(pmd_cache, pmd);
 300         }
 301         kmem_cache_free(pgd_cache, pgd);
 302         return NULL;
 303 }
 304
 305 void pgd_free(pgd_t *pgd)
 306 {
 307         int i;
 308
 309         /* in the PAE case user pgd entries are overwritten before usage */
 310         if (PTRS_PER_PMD > 1)
 311                 for (i = 0; i < USER_PTRS_PER_PGD; ++i) {
 312                         pgd_t pgdent = pgd[i];
 313                         void* pmd = (void *)__va(pgd_val(pgdent)-1);
 314                         paravirt_release_pd(__pa(pmd) >> PAGE_SHIFT);
 315                         kmem_cache_free(pmd_cache, pmd);
 316                 }
 317         /* in the non-PAE case, free_pgtables() clears user pgd entries */
 318         kmem_cache_free(pgd_cache, pgd);
 319 }