diff options
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/fremap.c | 22 | ||||
| -rw-r--r-- | mm/madvise.c | 2 | ||||
| -rw-r--r-- | mm/memory.c | 189 | ||||
| -rw-r--r-- | mm/mempolicy.c | 12 | ||||
| -rw-r--r-- | mm/msync.c | 12 | ||||
| -rw-r--r-- | mm/nommu.c | 2 | ||||
| -rw-r--r-- | mm/rmap.c | 14 |
7 files changed, 118 insertions, 135 deletions
diff --git a/mm/fremap.c b/mm/fremap.c index 007cbad9331e..f851775e09c2 100644 --- a/mm/fremap.c +++ b/mm/fremap.c @@ -27,24 +27,20 @@ static int zap_pte(struct mm_struct *mm, struct vm_area_struct *vma, struct page *page = NULL; if (pte_present(pte)) { - unsigned long pfn = pte_pfn(pte); - flush_cache_page(vma, addr, pfn); + flush_cache_page(vma, addr, pte_pfn(pte)); pte = ptep_clear_flush(vma, addr, ptep); - if (unlikely(!pfn_valid(pfn))) { - print_bad_pte(vma, pte, addr); - goto out; + page = vm_normal_page(vma, addr, pte); + if (page) { + if (pte_dirty(pte)) + set_page_dirty(page); + page_remove_rmap(page); + page_cache_release(page); } - page = pfn_to_page(pfn); - if (pte_dirty(pte)) - set_page_dirty(page); - page_remove_rmap(page); - page_cache_release(page); } else { if (!pte_file(pte)) free_swap_and_cache(pte_to_swp_entry(pte)); pte_clear(mm, addr, ptep); } -out: return !!page; } @@ -65,8 +61,6 @@ int install_page(struct mm_struct *mm, struct vm_area_struct *vma, pte_t pte_val; spinlock_t *ptl; - BUG_ON(vma->vm_flags & VM_UNPAGED); - pgd = pgd_offset(mm, addr); pud = pud_alloc(mm, pgd, addr); if (!pud) @@ -122,8 +116,6 @@ int install_file_pte(struct mm_struct *mm, struct vm_area_struct *vma, pte_t pte_val; spinlock_t *ptl; - BUG_ON(vma->vm_flags & VM_UNPAGED); - pgd = pgd_offset(mm, addr); pud = pud_alloc(mm, pgd, addr); if (!pud) diff --git a/mm/madvise.c b/mm/madvise.c index 328a3bcce527..2b7cf0400a21 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -126,7 +126,7 @@ static long madvise_dontneed(struct vm_area_struct * vma, unsigned long start, unsigned long end) { *prev = vma; - if (vma->vm_flags & (VM_LOCKED|VM_HUGETLB|VM_UNPAGED)) + if (vma->vm_flags & (VM_LOCKED|VM_HUGETLB|VM_PFNMAP)) return -EINVAL; if (unlikely(vma->vm_flags & VM_NONLINEAR)) { diff --git a/mm/memory.c b/mm/memory.c index d1f46f4e4c8a..b57fbc636058 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -333,9 +333,9 @@ static inline void add_mm_rss(struct mm_struct *mm, int file_rss, int anon_rss) } /* - * This function is called to print an error when a pte in a - * !VM_UNPAGED region is found pointing to an invalid pfn (which - * is an error. + * This function is called to print an error when a bad pte + * is found. For example, we might have a PFN-mapped pte in + * a region that doesn't allow it. * * The calling function must still handle the error. */ @@ -350,19 +350,56 @@ void print_bad_pte(struct vm_area_struct *vma, pte_t pte, unsigned long vaddr) } /* - * page_is_anon applies strict checks for an anonymous page belonging to - * this vma at this address. It is used on VM_UNPAGED vmas, which are - * usually populated with shared originals (which must not be counted), - * but occasionally contain private COWed copies (when !VM_SHARED, or - * perhaps via ptrace when VM_SHARED). An mmap of /dev/mem might window - * free pages, pages from other processes, or from other parts of this: - * it's tricky, but try not to be deceived by foreign anonymous pages. + * This function gets the "struct page" associated with a pte. + * + * NOTE! Some mappings do not have "struct pages". A raw PFN mapping + * will have each page table entry just pointing to a raw page frame + * number, and as far as the VM layer is concerned, those do not have + * pages associated with them - even if the PFN might point to memory + * that otherwise is perfectly fine and has a "struct page". + * + * The way we recognize those mappings is through the rules set up + * by "remap_pfn_range()": the vma will have the VM_PFNMAP bit set, + * and the vm_pgoff will point to the first PFN mapped: thus every + * page that is a raw mapping will always honor the rule + * + * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT) + * + * and if that isn't true, the page has been COW'ed (in which case it + * _does_ have a "struct page" associated with it even if it is in a + * VM_PFNMAP range). */ -static inline int page_is_anon(struct page *page, - struct vm_area_struct *vma, unsigned long addr) +struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr, pte_t pte) { - return page && PageAnon(page) && page_mapped(page) && - page_address_in_vma(page, vma) == addr; + unsigned long pfn = pte_pfn(pte); + + if (vma->vm_flags & VM_PFNMAP) { + unsigned long off = (addr - vma->vm_start) >> PAGE_SHIFT; + if (pfn == vma->vm_pgoff + off) + return NULL; + } + + /* + * Add some anal sanity checks for now. Eventually, + * we should just do "return pfn_to_page(pfn)", but + * in the meantime we check that we get a valid pfn, + * and that the resulting page looks ok. + * + * Remove this test eventually! + */ + if (unlikely(!pfn_valid(pfn))) { + print_bad_pte(vma, pte, addr); + return NULL; + } + + /* + * NOTE! We still have PageReserved() pages in the page + * tables. + * + * The PAGE_ZERO() pages and various VDSO mappings can + * cause them to exist. + */ + return pfn_to_page(pfn); } /* @@ -379,7 +416,6 @@ copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, unsigned long vm_flags = vma->vm_flags; pte_t pte = *src_pte; struct page *page; - unsigned long pfn; /* pte contains position in swap or file, so copy. */ if (unlikely(!pte_present(pte))) { @@ -397,22 +433,6 @@ copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, goto out_set_pte; } - pfn = pte_pfn(pte); - page = pfn_valid(pfn)? pfn_to_page(pfn): NULL; - - if (unlikely(vm_flags & VM_UNPAGED)) - if (!page_is_anon(page, vma, addr)) - goto out_set_pte; - - /* - * If the pte points outside of valid memory but - * the region is not VM_UNPAGED, we have a problem. - */ - if (unlikely(!page)) { - print_bad_pte(vma, pte, addr); - goto out_set_pte; /* try to do something sane */ - } - /* * If it's a COW mapping, write protect it both * in the parent and the child @@ -429,9 +449,13 @@ copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, if (vm_flags & VM_SHARED) pte = pte_mkclean(pte); pte = pte_mkold(pte); - get_page(page); - page_dup_rmap(page); - rss[!!PageAnon(page)]++; + + page = vm_normal_page(vma, addr, pte); + if (page) { + get_page(page); + page_dup_rmap(page); + rss[!!PageAnon(page)]++; + } out_set_pte: set_pte_at(dst_mm, addr, dst_pte, pte); @@ -543,7 +567,7 @@ int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, * readonly mappings. The tradeoff is that copy_page_range is more * efficient than faulting. */ - if (!(vma->vm_flags & (VM_HUGETLB|VM_NONLINEAR|VM_UNPAGED))) { + if (!(vma->vm_flags & (VM_HUGETLB|VM_NONLINEAR|VM_PFNMAP))) { if (!vma->anon_vma) return 0; } @@ -584,19 +608,10 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb, } if (pte_present(ptent)) { struct page *page; - unsigned long pfn; (*zap_work) -= PAGE_SIZE; - pfn = pte_pfn(ptent); - page = pfn_valid(pfn)? pfn_to_page(pfn): NULL; - - if (unlikely(vma->vm_flags & VM_UNPAGED)) { - if (!page_is_anon(page, vma, addr)) - page = NULL; - } else if (unlikely(!page)) - print_bad_pte(vma, ptent, addr); - + page = vm_normal_page(vma, addr, ptent); if (unlikely(details) && page) { /* * unmap_shared_mapping_pages() wants to @@ -852,7 +867,7 @@ unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address, /* * Do a quick page-table lookup for a single page. */ -struct page *follow_page(struct mm_struct *mm, unsigned long address, +struct page *follow_page(struct vm_area_struct *vma, unsigned long address, unsigned int flags) { pgd_t *pgd; @@ -860,8 +875,8 @@ struct page *follow_page(struct mm_struct *mm, unsigned long address, pmd_t *pmd; pte_t *ptep, pte; spinlock_t *ptl; - unsigned long pfn; struct page *page; + struct mm_struct *mm = vma->vm_mm; page = follow_huge_addr(mm, address, flags & FOLL_WRITE); if (!IS_ERR(page)) { @@ -897,11 +912,10 @@ struct page *follow_page(struct mm_struct *mm, unsigned long address, goto unlock; if ((flags & FOLL_WRITE) && !pte_write(pte)) goto unlock; - pfn = pte_pfn(pte); - if (!pfn_valid(pfn)) + page = vm_normal_page(vma, address, pte); + if (unlikely(!page)) goto unlock; - page = pfn_to_page(pfn); if (flags & FOLL_GET) get_page(page); if (flags & FOLL_TOUCH) { @@ -974,8 +988,10 @@ int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, return i ? : -EFAULT; } if (pages) { - pages[i] = pte_page(*pte); - get_page(pages[i]); + struct page *page = vm_normal_page(vma, start, *pte); + pages[i] = page; + if (page) + get_page(page); } pte_unmap(pte); if (vmas) @@ -1010,7 +1026,7 @@ int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, foll_flags |= FOLL_WRITE; cond_resched(); - while (!(page = follow_page(mm, start, foll_flags))) { + while (!(page = follow_page(vma, start, foll_flags))) { int ret; ret = __handle_mm_fault(mm, vma, start, foll_flags & FOLL_WRITE); @@ -1214,11 +1230,12 @@ int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr, * in 2.6 the LRU scan won't even find its pages, so this * flag means no more than count its pages in reserved_vm, * and omit it from core dump, even when VM_IO turned off. - * VM_UNPAGED tells the core MM not to "manage" these pages - * (e.g. refcount, mapcount, try to swap them out): in - * particular, zap_pte_range does not try to free them. + * VM_PFNMAP tells the core MM that the base pages are just + * raw PFN mappings, and do not have a "struct page" associated + * with them. */ - vma->vm_flags |= VM_IO | VM_RESERVED | VM_UNPAGED; + vma->vm_flags |= VM_IO | VM_RESERVED | VM_PFNMAP; + vma->vm_pgoff = pfn; BUG_ON(addr >= end); pfn -= addr >> PAGE_SHIFT; @@ -1273,6 +1290,26 @@ static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma) return pte; } +static inline void cow_user_page(struct page *dst, struct page *src, unsigned long va) +{ + /* + * If the source page was a PFN mapping, we don't have + * a "struct page" for it. We do a best-effort copy by + * just copying from the original user address. If that + * fails, we just zero-fill it. Live with it. + */ + if (unlikely(!src)) { + void *kaddr = kmap_atomic(dst, KM_USER0); + unsigned long left = __copy_from_user_inatomic(kaddr, (void __user *)va, PAGE_SIZE); + if (left) + memset(kaddr, 0, PAGE_SIZE); + kunmap_atomic(kaddr, KM_USER0); + return; + + } + copy_user_highpage(dst, src, va); +} + /* * This routine handles present pages, when users try to write * to a shared page. It is done by copying the page to a new address @@ -1296,28 +1333,13 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, spinlock_t *ptl, pte_t orig_pte) { struct page *old_page, *src_page, *new_page; - unsigned long pfn = pte_pfn(orig_pte); pte_t entry; int ret = VM_FAULT_MINOR; - if (unlikely(!pfn_valid(pfn))) { - /* - * Page table corrupted: show pte and kill process. - * Or it's an attempt to COW an out-of-map VM_UNPAGED - * entry, which copy_user_highpage does not support. - */ - print_bad_pte(vma, orig_pte, address); - ret = VM_FAULT_OOM; - goto unlock; - } - old_page = pfn_to_page(pfn); + old_page = vm_normal_page(vma, address, orig_pte); src_page = old_page; - - if (unlikely(vma->vm_flags & VM_UNPAGED)) - if (!page_is_anon(old_page, vma, address)) { - old_page = NULL; - goto gotten; - } + if (!old_page) + goto gotten; if (PageAnon(old_page) && !TestSetPageLocked(old_page)) { int reuse = can_share_swap_page(old_page); @@ -1351,7 +1373,7 @@ gotten: new_page = alloc_page_vma(GFP_HIGHUSER, vma, address); if (!new_page) goto oom; - copy_user_highpage(new_page, src_page, address); + cow_user_page(new_page, src_page, address); } /* @@ -1812,16 +1834,7 @@ static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma, spinlock_t *ptl; pte_t entry; - /* - * A VM_UNPAGED vma will normally be filled with present ptes - * by remap_pfn_range, and never arrive here; but it might have - * holes, or if !VM_DONTEXPAND, mremap might have expanded it. - * It's weird enough handling anon pages in unpaged vmas, we do - * not want to worry about ZERO_PAGEs too (it may or may not - * matter if their counts wrap): just give them anon pages. - */ - - if (write_access || (vma->vm_flags & VM_UNPAGED)) { + if (write_access) { /* Allocate our own private page. */ pte_unmap(page_table); @@ -1896,8 +1909,6 @@ static int do_no_page(struct mm_struct *mm, struct vm_area_struct *vma, int anon = 0; pte_unmap(page_table); - BUG_ON(vma->vm_flags & VM_UNPAGED); - if (vma->vm_file) { mapping = vma->vm_file->f_mapping; sequence = mapping->truncate_count; @@ -1930,7 +1941,7 @@ retry: page = alloc_page_vma(GFP_HIGHUSER, vma, address); if (!page) goto oom; - copy_user_highpage(page, new_page, address); + cow_user_page(page, new_page, address); page_cache_release(new_page); new_page = page; anon = 1; diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 5609a31bdf22..bec88c81244e 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -189,17 +189,15 @@ static int check_pte_range(struct vm_area_struct *vma, pmd_t *pmd, orig_pte = pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); do { - unsigned long pfn; + struct page *page; unsigned int nid; if (!pte_present(*pte)) continue; - pfn = pte_pfn(*pte); - if (!pfn_valid(pfn)) { - print_bad_pte(vma, *pte, addr); + page = vm_normal_page(vma, addr, *pte); + if (!page) continue; - } - nid = pfn_to_nid(pfn); + nid = page_to_nid(page); if (!node_isset(nid, *nodes)) break; } while (pte++, addr += PAGE_SIZE, addr != end); @@ -269,8 +267,6 @@ check_range(struct mm_struct *mm, unsigned long start, unsigned long end, first = find_vma(mm, start); if (!first) return ERR_PTR(-EFAULT); - if (first->vm_flags & VM_UNPAGED) - return ERR_PTR(-EACCES); prev = NULL; for (vma = first; vma && vma->vm_start < end; vma = vma->vm_next) { if (!vma->vm_next && vma->vm_end < end) diff --git a/mm/msync.c b/mm/msync.c index b3f4caf3010b..1b5b6f662dcf 100644 --- a/mm/msync.c +++ b/mm/msync.c @@ -27,7 +27,6 @@ static void msync_pte_range(struct vm_area_struct *vma, pmd_t *pmd, again: pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); do { - unsigned long pfn; struct page *page; if (progress >= 64) { @@ -40,13 +39,9 @@ again: continue; if (!pte_maybe_dirty(*pte)) continue; - pfn = pte_pfn(*pte); - if (unlikely(!pfn_valid(pfn))) { - print_bad_pte(vma, *pte, addr); + page = vm_normal_page(vma, addr, *pte); + if (!page) continue; - } - page = pfn_to_page(pfn); - if (ptep_clear_flush_dirty(vma, addr, pte) || page_test_and_clear_dirty(page)) set_page_dirty(page); @@ -97,9 +92,8 @@ static void msync_page_range(struct vm_area_struct *vma, /* For hugepages we can't go walking the page table normally, * but that's ok, hugetlbfs is memory based, so we don't need * to do anything more on an msync(). - * Can't do anything with VM_UNPAGED regions either. */ - if (vma->vm_flags & (VM_HUGETLB|VM_UNPAGED)) + if (vma->vm_flags & VM_HUGETLB) return; BUG_ON(addr >= end); diff --git a/mm/nommu.c b/mm/nommu.c index 6deb6ab3d6ad..c1196812876b 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -1045,7 +1045,7 @@ struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr) EXPORT_SYMBOL(find_vma); -struct page *follow_page(struct mm_struct *mm, unsigned long address, +struct page *follow_page(struct vm_area_struct *vma, unsigned long address, unsigned int foll_flags) { return NULL; diff --git a/mm/rmap.c b/mm/rmap.c index 2e034a0b89ab..6389cda02a20 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -226,8 +226,6 @@ vma_address(struct page *page, struct vm_area_struct *vma) /* * At what user virtual address is page expected in vma? checking that the * page matches the vma: currently only used on anon pages, by unuse_vma; - * and by extraordinary checks on anon pages in VM_UNPAGED vmas, taking - * care that an mmap of /dev/mem might window free and foreign pages. */ unsigned long page_address_in_vma(struct page *page, struct vm_area_struct *vma) { @@ -614,7 +612,6 @@ static void try_to_unmap_cluster(unsigned long cursor, struct page *page; unsigned long address; unsigned long end; - unsigned long pfn; address = (vma->vm_start + cursor) & CLUSTER_MASK; end = address + CLUSTER_SIZE; @@ -643,15 +640,8 @@ static void try_to_unmap_cluster(unsigned long cursor, for (; address < end; pte++, address += PAGE_SIZE) { if (!pte_present(*pte)) continue; - - pfn = pte_pfn(*pte); - if (unlikely(!pfn_valid(pfn))) { - print_bad_pte(vma, *pte, address); - continue; - } - - page = pfn_to_page(pfn); - BUG_ON(PageAnon(page)); + page = vm_normal_page(vma, address, *pte); + BUG_ON(!page || PageAnon(page)); if (ptep_clear_flush_young(vma, address, pte)) continue; |