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