From b1f9e876862d8f7176299ec4fb2108bc1045cbc8 Mon Sep 17 00:00:00 2001 From: Peter Xu Date: Thu, 12 May 2022 20:22:56 -0700 Subject: mm/uffd: enable write protection for shmem & hugetlbfs We've had all the necessary changes ready for both shmem and hugetlbfs. Turn on all the shmem/hugetlbfs switches for userfaultfd-wp. We can expand UFFD_API_RANGE_IOCTLS_BASIC with _UFFDIO_WRITEPROTECT too because all existing types now support write protection mode. Since vma_can_userfault() will be used elsewhere, move into userfaultfd_k.h. Link: https://lkml.kernel.org/r/20220405014926.15101-1-peterx@redhat.com Signed-off-by: Peter Xu Cc: Alistair Popple Cc: Andrea Arcangeli Cc: Axel Rasmussen Cc: David Hildenbrand Cc: Hugh Dickins Cc: Jerome Glisse Cc: "Kirill A . Shutemov" Cc: Matthew Wilcox Cc: Mike Kravetz Cc: Mike Rapoport Cc: Nadav Amit Signed-off-by: Andrew Morton --- fs/userfaultfd.c | 21 +++------------------ 1 file changed, 3 insertions(+), 18 deletions(-) (limited to 'fs/userfaultfd.c') diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c index 78b68e0f9774..e943370107d0 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -1258,24 +1258,6 @@ static __always_inline int validate_range(struct mm_struct *mm, return 0; } -static inline bool vma_can_userfault(struct vm_area_struct *vma, - unsigned long vm_flags) -{ - /* FIXME: add WP support to hugetlbfs and shmem */ - if (vm_flags & VM_UFFD_WP) { - if (is_vm_hugetlb_page(vma) || vma_is_shmem(vma)) - return false; - } - - if (vm_flags & VM_UFFD_MINOR) { - if (!(is_vm_hugetlb_page(vma) || vma_is_shmem(vma))) - return false; - } - - return vma_is_anonymous(vma) || is_vm_hugetlb_page(vma) || - vma_is_shmem(vma); -} - static int userfaultfd_register(struct userfaultfd_ctx *ctx, unsigned long arg) { @@ -1956,6 +1938,9 @@ static int userfaultfd_api(struct userfaultfd_ctx *ctx, #endif #ifndef CONFIG_HAVE_ARCH_USERFAULTFD_WP uffdio_api.features &= ~UFFD_FEATURE_PAGEFAULT_FLAG_WP; +#endif +#ifndef CONFIG_PTE_MARKER_UFFD_WP + uffdio_api.features &= ~UFFD_FEATURE_WP_HUGETLBFS_SHMEM; #endif uffdio_api.ioctls = UFFD_API_IOCTLS; ret = -EFAULT; -- cgit v1.2.3