#include #include #include pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address) { return (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO); } pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address) { struct page *pte; #ifdef CONFIG_HIGHPTE pte = alloc_pages(GFP_KERNEL|__GFP_HIGHMEM|__GFP_REPEAT|__GFP_ZERO, 0); #else pte = alloc_pages(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO, 0); #endif if (pte) pgtable_page_ctor(pte); return pte; } #ifdef CONFIG_X86_64 static inline void pgd_list_add(pgd_t *pgd) { struct page *page = virt_to_page(pgd); unsigned long flags; spin_lock_irqsave(&pgd_lock, flags); list_add(&page->lru, &pgd_list); spin_unlock_irqrestore(&pgd_lock, flags); } static inline void pgd_list_del(pgd_t *pgd) { struct page *page = virt_to_page(pgd); unsigned long flags; spin_lock_irqsave(&pgd_lock, flags); list_del(&page->lru); spin_unlock_irqrestore(&pgd_lock, flags); } pgd_t *pgd_alloc(struct mm_struct *mm) { unsigned boundary; pgd_t *pgd = (pgd_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT); if (!pgd) return NULL; pgd_list_add(pgd); /* * Copy kernel pointers in from init. * Could keep a freelist or slab cache of those because the kernel * part never changes. */ boundary = pgd_index(__PAGE_OFFSET); memset(pgd, 0, boundary * sizeof(pgd_t)); memcpy(pgd + boundary, init_level4_pgt + boundary, (PTRS_PER_PGD - boundary) * sizeof(pgd_t)); return pgd; } void pgd_free(struct mm_struct *mm, pgd_t *pgd) { BUG_ON((unsigned long)pgd & (PAGE_SIZE-1)); pgd_list_del(pgd); free_page((unsigned long)pgd); } #else /* * List of all pgd's needed for non-PAE so it can invalidate entries * in both cached and uncached pgd's; not needed for PAE since the * kernel pmd is shared. If PAE were not to share the pmd a similar * tactic would be needed. This is essentially codepath-based locking * against pageattr.c; it is the unique case in which a valid change * of kernel pagetables can't be lazily synchronized by vmalloc faults. * vmalloc faults work because attached pagetables are never freed. * -- wli */ static inline void pgd_list_add(pgd_t *pgd) { struct page *page = virt_to_page(pgd); list_add(&page->lru, &pgd_list); } static inline void pgd_list_del(pgd_t *pgd) { struct page *page = virt_to_page(pgd); list_del(&page->lru); } #define UNSHARED_PTRS_PER_PGD \ (SHARED_KERNEL_PMD ? USER_PTRS_PER_PGD : PTRS_PER_PGD) static void pgd_ctor(void *p) { pgd_t *pgd = p; unsigned long flags; /* Clear usermode parts of PGD */ memset(pgd, 0, USER_PTRS_PER_PGD*sizeof(pgd_t)); spin_lock_irqsave(&pgd_lock, flags); /* If the pgd points to a shared pagetable level (either the ptes in non-PAE, or shared PMD in PAE), then just copy the references from swapper_pg_dir. */ if (PAGETABLE_LEVELS == 2 || (PAGETABLE_LEVELS == 3 && SHARED_KERNEL_PMD)) { clone_pgd_range(pgd + USER_PTRS_PER_PGD, swapper_pg_dir + USER_PTRS_PER_PGD, KERNEL_PGD_PTRS); paravirt_alloc_pd_clone(__pa(pgd) >> PAGE_SHIFT, __pa(swapper_pg_dir) >> PAGE_SHIFT, USER_PTRS_PER_PGD, KERNEL_PGD_PTRS); } /* list required to sync kernel mapping updates */ if (!SHARED_KERNEL_PMD) pgd_list_add(pgd); spin_unlock_irqrestore(&pgd_lock, flags); } static void pgd_dtor(void *pgd) { unsigned long flags; /* can be called from interrupt context */ if (SHARED_KERNEL_PMD) return; spin_lock_irqsave(&pgd_lock, flags); pgd_list_del(pgd); spin_unlock_irqrestore(&pgd_lock, flags); } #ifdef CONFIG_X86_PAE /* * Mop up any pmd pages which may still be attached to the pgd. * Normally they will be freed by munmap/exit_mmap, but any pmd we * preallocate which never got a corresponding vma will need to be * freed manually. */ static void pgd_mop_up_pmds(struct mm_struct *mm, pgd_t *pgdp) { int i; for(i = 0; i < UNSHARED_PTRS_PER_PGD; i++) { pgd_t pgd = pgdp[i]; if (pgd_val(pgd) != 0) { pmd_t *pmd = (pmd_t *)pgd_page_vaddr(pgd); pgdp[i] = native_make_pgd(0); paravirt_release_pd(pgd_val(pgd) >> PAGE_SHIFT); pmd_free(mm, pmd); } } } /* * In PAE mode, we need to do a cr3 reload (=tlb flush) when * updating the top-level pagetable entries to guarantee the * processor notices the update. Since this is expensive, and * all 4 top-level entries are used almost immediately in a * new process's life, we just pre-populate them here. * * Also, if we're in a paravirt environment where the kernel pmd is * not shared between pagetables (!SHARED_KERNEL_PMDS), we allocate * and initialize the kernel pmds here. */ static int pgd_prepopulate_pmd(struct mm_struct *mm, pgd_t *pgd) { pud_t *pud; unsigned long addr; int i; pud = pud_offset(pgd, 0); for (addr = i = 0; i < UNSHARED_PTRS_PER_PGD; i++, pud++, addr += PUD_SIZE) { pmd_t *pmd = pmd_alloc_one(mm, addr); if (!pmd) { pgd_mop_up_pmds(mm, pgd); return 0; } if (i >= USER_PTRS_PER_PGD) memcpy(pmd, (pmd_t *)pgd_page_vaddr(swapper_pg_dir[i]), sizeof(pmd_t) * PTRS_PER_PMD); pud_populate(mm, pud, pmd); } return 1; } void pud_populate(struct mm_struct *mm, pud_t *pudp, pmd_t *pmd) { paravirt_alloc_pd(mm, __pa(pmd) >> PAGE_SHIFT); /* Note: almost everything apart from _PAGE_PRESENT is reserved at the pmd (PDPT) level. */ set_pud(pudp, __pud(__pa(pmd) | _PAGE_PRESENT)); /* * According to Intel App note "TLBs, Paging-Structure Caches, * and Their Invalidation", April 2007, document 317080-001, * section 8.1: in PAE mode we explicitly have to flush the * TLB via cr3 if the top-level pgd is changed... */ if (mm == current->active_mm) write_cr3(read_cr3()); } #else /* !CONFIG_X86_PAE */ /* No need to prepopulate any pagetable entries in non-PAE modes. */ static int pgd_prepopulate_pmd(struct mm_struct *mm, pgd_t *pgd) { return 1; } static void pgd_mop_up_pmds(struct mm_struct *mm, pgd_t *pgd) { } #endif /* CONFIG_X86_PAE */ pgd_t *pgd_alloc(struct mm_struct *mm) { pgd_t *pgd = (pgd_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO); /* so that alloc_pd can use it */ mm->pgd = pgd; if (pgd) pgd_ctor(pgd); if (pgd && !pgd_prepopulate_pmd(mm, pgd)) { pgd_dtor(pgd); free_page((unsigned long)pgd); pgd = NULL; } return pgd; } void pgd_free(struct mm_struct *mm, pgd_t *pgd) { pgd_mop_up_pmds(mm, pgd); pgd_dtor(pgd); free_page((unsigned long)pgd); } #endif