/arch/i386/mm/pgtable.c

https://bitbucket.org/evzijst/gittest · C · 260 lines · 192 code · 31 blank · 37 comment · 27 complexity · 0de2d333a7702edc466a39be7fe347a2 MD5 · raw file

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