| #include <linux/mm.h> |
| #include <linux/gfp.h> |
| #include <asm/pgalloc.h> |
| #include <asm/pgtable.h> |
| #include <asm/tlb.h> |
| #include <asm/fixmap.h> |
| #include <asm/mtrr.h> |
| |
| #define PGALLOC_GFP (GFP_KERNEL_ACCOUNT | __GFP_NOTRACK | __GFP_ZERO) |
| |
| #ifdef CONFIG_HIGHPTE |
| #define PGALLOC_USER_GFP __GFP_HIGHMEM |
| #else |
| #define PGALLOC_USER_GFP 0 |
| #endif |
| |
| gfp_t __userpte_alloc_gfp = PGALLOC_GFP | PGALLOC_USER_GFP; |
| |
| pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address) |
| { |
| return (pte_t *)__get_free_page(PGALLOC_GFP & ~__GFP_ACCOUNT); |
| } |
| |
| pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address) |
| { |
| struct page *pte; |
| |
| pte = alloc_pages(__userpte_alloc_gfp, 0); |
| if (!pte) |
| return NULL; |
| if (!pgtable_page_ctor(pte)) { |
| __free_page(pte); |
| return NULL; |
| } |
| return pte; |
| } |
| |
| static int __init setup_userpte(char *arg) |
| { |
| if (!arg) |
| return -EINVAL; |
| |
| /* |
| * "userpte=nohigh" disables allocation of user pagetables in |
| * high memory. |
| */ |
| if (strcmp(arg, "nohigh") == 0) |
| __userpte_alloc_gfp &= ~__GFP_HIGHMEM; |
| else |
| return -EINVAL; |
| return 0; |
| } |
| early_param("userpte", setup_userpte); |
| |
| void ___pte_free_tlb(struct mmu_gather *tlb, struct page *pte) |
| { |
| pgtable_page_dtor(pte); |
| paravirt_release_pte(page_to_pfn(pte)); |
| tlb_remove_page(tlb, pte); |
| } |
| |
| #if CONFIG_PGTABLE_LEVELS > 2 |
| void ___pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd) |
| { |
| struct page *page = virt_to_page(pmd); |
| paravirt_release_pmd(__pa(pmd) >> PAGE_SHIFT); |
| /* |
| * NOTE! For PAE, any changes to the top page-directory-pointer-table |
| * entries need a full cr3 reload to flush. |
| */ |
| #ifdef CONFIG_X86_PAE |
| tlb->need_flush_all = 1; |
| #endif |
| pgtable_pmd_page_dtor(page); |
| tlb_remove_page(tlb, page); |
| } |
| |
| #if CONFIG_PGTABLE_LEVELS > 3 |
| void ___pud_free_tlb(struct mmu_gather *tlb, pud_t *pud) |
| { |
| paravirt_release_pud(__pa(pud) >> PAGE_SHIFT); |
| tlb_remove_page(tlb, virt_to_page(pud)); |
| } |
| #endif /* CONFIG_PGTABLE_LEVELS > 3 */ |
| #endif /* CONFIG_PGTABLE_LEVELS > 2 */ |
| |
| 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 ? KERNEL_PGD_BOUNDARY : PTRS_PER_PGD) |
| |
| |
| static void pgd_set_mm(pgd_t *pgd, struct mm_struct *mm) |
| { |
| BUILD_BUG_ON(sizeof(virt_to_page(pgd)->index) < sizeof(mm)); |
| virt_to_page(pgd)->index = (pgoff_t)mm; |
| } |
| |
| struct mm_struct *pgd_page_get_mm(struct page *page) |
| { |
| return (struct mm_struct *)page->index; |
| } |
| |
| static void pgd_ctor(struct mm_struct *mm, pgd_t *pgd) |
| { |
| /* 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 (CONFIG_PGTABLE_LEVELS == 2 || |
| (CONFIG_PGTABLE_LEVELS == 3 && SHARED_KERNEL_PMD) || |
| CONFIG_PGTABLE_LEVELS == 4) { |
| clone_pgd_range(pgd + KERNEL_PGD_BOUNDARY, |
| swapper_pg_dir + KERNEL_PGD_BOUNDARY, |
| KERNEL_PGD_PTRS); |
| } |
| |
| /* list required to sync kernel mapping updates */ |
| if (!SHARED_KERNEL_PMD) { |
| pgd_set_mm(pgd, mm); |
| pgd_list_add(pgd); |
| } |
| } |
| |
| static void pgd_dtor(pgd_t *pgd) |
| { |
| if (SHARED_KERNEL_PMD) |
| return; |
| |
| spin_lock(&pgd_lock); |
| pgd_list_del(pgd); |
| spin_unlock(&pgd_lock); |
| } |
| |
| /* |
| * 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. |
| * -- nyc |
| */ |
| |
| #ifdef CONFIG_X86_PAE |
| /* |
| * 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. |
| */ |
| #define PREALLOCATED_PMDS UNSHARED_PTRS_PER_PGD |
| |
| void pud_populate(struct mm_struct *mm, pud_t *pudp, pmd_t *pmd) |
| { |
| paravirt_alloc_pmd(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... |
| */ |
| flush_tlb_mm(mm); |
| } |
| #else /* !CONFIG_X86_PAE */ |
| |
| /* No need to prepopulate any pagetable entries in non-PAE modes. */ |
| #define PREALLOCATED_PMDS 0 |
| |
| #endif /* CONFIG_X86_PAE */ |
| |
| static void free_pmds(struct mm_struct *mm, pmd_t *pmds[]) |
| { |
| int i; |
| |
| for(i = 0; i < PREALLOCATED_PMDS; i++) |
| if (pmds[i]) { |
| pgtable_pmd_page_dtor(virt_to_page(pmds[i])); |
| free_page((unsigned long)pmds[i]); |
| mm_dec_nr_pmds(mm); |
| } |
| } |
| |
| static int preallocate_pmds(struct mm_struct *mm, pmd_t *pmds[]) |
| { |
| int i; |
| bool failed = false; |
| gfp_t gfp = PGALLOC_GFP; |
| |
| if (mm == &init_mm) |
| gfp &= ~__GFP_ACCOUNT; |
| |
| for(i = 0; i < PREALLOCATED_PMDS; i++) { |
| pmd_t *pmd = (pmd_t *)__get_free_page(gfp); |
| if (!pmd) |
| failed = true; |
| if (pmd && !pgtable_pmd_page_ctor(virt_to_page(pmd))) { |
| free_page((unsigned long)pmd); |
| pmd = NULL; |
| failed = true; |
| } |
| if (pmd) |
| mm_inc_nr_pmds(mm); |
| pmds[i] = pmd; |
| } |
| |
| if (failed) { |
| free_pmds(mm, pmds); |
| return -ENOMEM; |
| } |
| |
| return 0; |
| } |
| |
| /* |
| * 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 < PREALLOCATED_PMDS; 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_pmd(pgd_val(pgd) >> PAGE_SHIFT); |
| pmd_free(mm, pmd); |
| mm_dec_nr_pmds(mm); |
| } |
| } |
| } |
| |
| static void pgd_prepopulate_pmd(struct mm_struct *mm, pgd_t *pgd, pmd_t *pmds[]) |
| { |
| p4d_t *p4d; |
| pud_t *pud; |
| int i; |
| |
| if (PREALLOCATED_PMDS == 0) /* Work around gcc-3.4.x bug */ |
| return; |
| |
| p4d = p4d_offset(pgd, 0); |
| pud = pud_offset(p4d, 0); |
| |
| for (i = 0; i < PREALLOCATED_PMDS; i++, pud++) { |
| pmd_t *pmd = pmds[i]; |
| |
| if (i >= KERNEL_PGD_BOUNDARY) |
| memcpy(pmd, (pmd_t *)pgd_page_vaddr(swapper_pg_dir[i]), |
| sizeof(pmd_t) * PTRS_PER_PMD); |
| |
| pud_populate(mm, pud, pmd); |
| } |
| } |
| |
| /* |
| * Xen paravirt assumes pgd table should be in one page. 64 bit kernel also |
| * assumes that pgd should be in one page. |
| * |
| * But kernel with PAE paging that is not running as a Xen domain |
| * only needs to allocate 32 bytes for pgd instead of one page. |
| */ |
| #ifdef CONFIG_X86_PAE |
| |
| #include <linux/slab.h> |
| |
| #define PGD_SIZE (PTRS_PER_PGD * sizeof(pgd_t)) |
| #define PGD_ALIGN 32 |
| |
| static struct kmem_cache *pgd_cache; |
| |
| static int __init pgd_cache_init(void) |
| { |
| /* |
| * When PAE kernel is running as a Xen domain, it does not use |
| * shared kernel pmd. And this requires a whole page for pgd. |
| */ |
| if (!SHARED_KERNEL_PMD) |
| return 0; |
| |
| /* |
| * when PAE kernel is not running as a Xen domain, it uses |
| * shared kernel pmd. Shared kernel pmd does not require a whole |
| * page for pgd. We are able to just allocate a 32-byte for pgd. |
| * During boot time, we create a 32-byte slab for pgd table allocation. |
| */ |
| pgd_cache = kmem_cache_create("pgd_cache", PGD_SIZE, PGD_ALIGN, |
| SLAB_PANIC, NULL); |
| if (!pgd_cache) |
| return -ENOMEM; |
| |
| return 0; |
| } |
| core_initcall(pgd_cache_init); |
| |
| static inline pgd_t *_pgd_alloc(void) |
| { |
| /* |
| * If no SHARED_KERNEL_PMD, PAE kernel is running as a Xen domain. |
| * We allocate one page for pgd. |
| */ |
| if (!SHARED_KERNEL_PMD) |
| return (pgd_t *)__get_free_page(PGALLOC_GFP); |
| |
| /* |
| * Now PAE kernel is not running as a Xen domain. We can allocate |
| * a 32-byte slab for pgd to save memory space. |
| */ |
| return kmem_cache_alloc(pgd_cache, PGALLOC_GFP); |
| } |
| |
| static inline void _pgd_free(pgd_t *pgd) |
| { |
| if (!SHARED_KERNEL_PMD) |
| free_page((unsigned long)pgd); |
| else |
| kmem_cache_free(pgd_cache, pgd); |
| } |
| #else |
| static inline pgd_t *_pgd_alloc(void) |
| { |
| return (pgd_t *)__get_free_page(PGALLOC_GFP); |
| } |
| |
| static inline void _pgd_free(pgd_t *pgd) |
| { |
| free_page((unsigned long)pgd); |
| } |
| #endif /* CONFIG_X86_PAE */ |
| |
| pgd_t *pgd_alloc(struct mm_struct *mm) |
| { |
| pgd_t *pgd; |
| pmd_t *pmds[PREALLOCATED_PMDS]; |
| |
| pgd = _pgd_alloc(); |
| |
| if (pgd == NULL) |
| goto out; |
| |
| mm->pgd = pgd; |
| |
| if (preallocate_pmds(mm, pmds) != 0) |
| goto out_free_pgd; |
| |
| if (paravirt_pgd_alloc(mm) != 0) |
| goto out_free_pmds; |
| |
| /* |
| * Make sure that pre-populating the pmds is atomic with |
| * respect to anything walking the pgd_list, so that they |
| * never see a partially populated pgd. |
| */ |
| spin_lock(&pgd_lock); |
| |
| pgd_ctor(mm, pgd); |
| pgd_prepopulate_pmd(mm, pgd, pmds); |
| |
| spin_unlock(&pgd_lock); |
| |
| return pgd; |
| |
| out_free_pmds: |
| free_pmds(mm, pmds); |
| out_free_pgd: |
| _pgd_free(pgd); |
| out: |
| return NULL; |
| } |
| |
| void pgd_free(struct mm_struct *mm, pgd_t *pgd) |
| { |
| pgd_mop_up_pmds(mm, pgd); |
| pgd_dtor(pgd); |
| paravirt_pgd_free(mm, pgd); |
| _pgd_free(pgd); |
| } |
| |
| /* |
| * Used to set accessed or dirty bits in the page table entries |
| * on other architectures. On x86, the accessed and dirty bits |
| * are tracked by hardware. However, do_wp_page calls this function |
| * to also make the pte writeable at the same time the dirty bit is |
| * set. In that case we do actually need to write the PTE. |
| */ |
| int ptep_set_access_flags(struct vm_area_struct *vma, |
| unsigned long address, pte_t *ptep, |
| pte_t entry, int dirty) |
| { |
| int changed = !pte_same(*ptep, entry); |
| |
| if (changed && dirty) { |
| *ptep = entry; |
| pte_update(vma->vm_mm, address, ptep); |
| } |
| |
| return changed; |
| } |
| |
| #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
| int pmdp_set_access_flags(struct vm_area_struct *vma, |
| unsigned long address, pmd_t *pmdp, |
| pmd_t entry, int dirty) |
| { |
| int changed = !pmd_same(*pmdp, entry); |
| |
| VM_BUG_ON(address & ~HPAGE_PMD_MASK); |
| |
| if (changed && dirty) { |
| *pmdp = entry; |
| /* |
| * We had a write-protection fault here and changed the pmd |
| * to to more permissive. No need to flush the TLB for that, |
| * #PF is architecturally guaranteed to do that and in the |
| * worst-case we'll generate a spurious fault. |
| */ |
| } |
| |
| return changed; |
| } |
| |
| int pudp_set_access_flags(struct vm_area_struct *vma, unsigned long address, |
| pud_t *pudp, pud_t entry, int dirty) |
| { |
| int changed = !pud_same(*pudp, entry); |
| |
| VM_BUG_ON(address & ~HPAGE_PUD_MASK); |
| |
| if (changed && dirty) { |
| *pudp = entry; |
| /* |
| * We had a write-protection fault here and changed the pud |
| * to to more permissive. No need to flush the TLB for that, |
| * #PF is architecturally guaranteed to do that and in the |
| * worst-case we'll generate a spurious fault. |
| */ |
| } |
| |
| return changed; |
| } |
| #endif |
| |
| int ptep_test_and_clear_young(struct vm_area_struct *vma, |
| unsigned long addr, pte_t *ptep) |
| { |
| int ret = 0; |
| |
| if (pte_young(*ptep)) |
| ret = test_and_clear_bit(_PAGE_BIT_ACCESSED, |
| (unsigned long *) &ptep->pte); |
| |
| if (ret) |
| pte_update(vma->vm_mm, addr, ptep); |
| |
| return ret; |
| } |
| |
| #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
| int pmdp_test_and_clear_young(struct vm_area_struct *vma, |
| unsigned long addr, pmd_t *pmdp) |
| { |
| int ret = 0; |
| |
| if (pmd_young(*pmdp)) |
| ret = test_and_clear_bit(_PAGE_BIT_ACCESSED, |
| (unsigned long *)pmdp); |
| |
| return ret; |
| } |
| int pudp_test_and_clear_young(struct vm_area_struct *vma, |
| unsigned long addr, pud_t *pudp) |
| { |
| int ret = 0; |
| |
| if (pud_young(*pudp)) |
| ret = test_and_clear_bit(_PAGE_BIT_ACCESSED, |
| (unsigned long *)pudp); |
| |
| return ret; |
| } |
| #endif |
| |
| int ptep_clear_flush_young(struct vm_area_struct *vma, |
| unsigned long address, pte_t *ptep) |
| { |
| /* |
| * On x86 CPUs, clearing the accessed bit without a TLB flush |
| * doesn't cause data corruption. [ It could cause incorrect |
| * page aging and the (mistaken) reclaim of hot pages, but the |
| * chance of that should be relatively low. ] |
| * |
| * So as a performance optimization don't flush the TLB when |
| * clearing the accessed bit, it will eventually be flushed by |
| * a context switch or a VM operation anyway. [ In the rare |
| * event of it not getting flushed for a long time the delay |
| * shouldn't really matter because there's no real memory |
| * pressure for swapout to react to. ] |
| */ |
| return ptep_test_and_clear_young(vma, address, ptep); |
| } |
| |
| #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
| int pmdp_clear_flush_young(struct vm_area_struct *vma, |
| unsigned long address, pmd_t *pmdp) |
| { |
| int young; |
| |
| VM_BUG_ON(address & ~HPAGE_PMD_MASK); |
| |
| young = pmdp_test_and_clear_young(vma, address, pmdp); |
| if (young) |
| flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE); |
| |
| return young; |
| } |
| #endif |
| |
| /** |
| * reserve_top_address - reserves a hole in the top of kernel address space |
| * @reserve - size of hole to reserve |
| * |
| * Can be used to relocate the fixmap area and poke a hole in the top |
| * of kernel address space to make room for a hypervisor. |
| */ |
| void __init reserve_top_address(unsigned long reserve) |
| { |
| #ifdef CONFIG_X86_32 |
| BUG_ON(fixmaps_set > 0); |
| __FIXADDR_TOP = round_down(-reserve, 1 << PMD_SHIFT) - PAGE_SIZE; |
| printk(KERN_INFO "Reserving virtual address space above 0x%08lx (rounded to 0x%08lx)\n", |
| -reserve, __FIXADDR_TOP + PAGE_SIZE); |
| #endif |
| } |
| |
| int fixmaps_set; |
| |
| void __native_set_fixmap(enum fixed_addresses idx, pte_t pte) |
| { |
| unsigned long address = __fix_to_virt(idx); |
| |
| if (idx >= __end_of_fixed_addresses) { |
| BUG(); |
| return; |
| } |
| set_pte_vaddr(address, pte); |
| fixmaps_set++; |
| } |
| |
| void native_set_fixmap(enum fixed_addresses idx, phys_addr_t phys, |
| pgprot_t flags) |
| { |
| __native_set_fixmap(idx, pfn_pte(phys >> PAGE_SHIFT, flags)); |
| } |
| |
| #ifdef CONFIG_HAVE_ARCH_HUGE_VMAP |
| /** |
| * pud_set_huge - setup kernel PUD mapping |
| * |
| * MTRRs can override PAT memory types with 4KiB granularity. Therefore, this |
| * function sets up a huge page only if any of the following conditions are met: |
| * |
| * - MTRRs are disabled, or |
| * |
| * - MTRRs are enabled and the range is completely covered by a single MTRR, or |
| * |
| * - MTRRs are enabled and the corresponding MTRR memory type is WB, which |
| * has no effect on the requested PAT memory type. |
| * |
| * Callers should try to decrease page size (1GB -> 2MB -> 4K) if the bigger |
| * page mapping attempt fails. |
| * |
| * Returns 1 on success and 0 on failure. |
| */ |
| int pud_set_huge(pud_t *pud, phys_addr_t addr, pgprot_t prot) |
| { |
| u8 mtrr, uniform; |
| |
| mtrr = mtrr_type_lookup(addr, addr + PUD_SIZE, &uniform); |
| if ((mtrr != MTRR_TYPE_INVALID) && (!uniform) && |
| (mtrr != MTRR_TYPE_WRBACK)) |
| return 0; |
| |
| prot = pgprot_4k_2_large(prot); |
| |
| set_pte((pte_t *)pud, pfn_pte( |
| (u64)addr >> PAGE_SHIFT, |
| __pgprot(pgprot_val(prot) | _PAGE_PSE))); |
| |
| return 1; |
| } |
| |
| /** |
| * pmd_set_huge - setup kernel PMD mapping |
| * |
| * See text over pud_set_huge() above. |
| * |
| * Returns 1 on success and 0 on failure. |
| */ |
| int pmd_set_huge(pmd_t *pmd, phys_addr_t addr, pgprot_t prot) |
| { |
| u8 mtrr, uniform; |
| |
| mtrr = mtrr_type_lookup(addr, addr + PMD_SIZE, &uniform); |
| if ((mtrr != MTRR_TYPE_INVALID) && (!uniform) && |
| (mtrr != MTRR_TYPE_WRBACK)) { |
| pr_warn_once("%s: Cannot satisfy [mem %#010llx-%#010llx] with a huge-page mapping due to MTRR override.\n", |
| __func__, addr, addr + PMD_SIZE); |
| return 0; |
| } |
| |
| prot = pgprot_4k_2_large(prot); |
| |
| set_pte((pte_t *)pmd, pfn_pte( |
| (u64)addr >> PAGE_SHIFT, |
| __pgprot(pgprot_val(prot) | _PAGE_PSE))); |
| |
| return 1; |
| } |
| |
| /** |
| * pud_clear_huge - clear kernel PUD mapping when it is set |
| * |
| * Returns 1 on success and 0 on failure (no PUD map is found). |
| */ |
| int pud_clear_huge(pud_t *pud) |
| { |
| if (pud_large(*pud)) { |
| pud_clear(pud); |
| return 1; |
| } |
| |
| return 0; |
| } |
| |
| /** |
| * pmd_clear_huge - clear kernel PMD mapping when it is set |
| * |
| * Returns 1 on success and 0 on failure (no PMD map is found). |
| */ |
| int pmd_clear_huge(pmd_t *pmd) |
| { |
| if (pmd_large(*pmd)) { |
| pmd_clear(pmd); |
| return 1; |
| } |
| |
| return 0; |
| } |
| #endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */ |