Commit fb8e37f3 authored by Peter Xu's avatar Peter Xu Committed by Linus Torvalds
Browse files

mm/pagemap: export uffd-wp protection information 

Export the PTE/PMD status of uffd-wp to pagemap too.

Link: https://lkml.kernel.org/r/20210428225030.9708-6-peterx@redhat.com


Signed-off-by: default avatarPeter Xu <peterx@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Brian Geffon <bgeffon@google.com>
Cc: "Dr . David Alan Gilbert" <dgilbert@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Lokesh Gidra <lokeshgidra@google.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Oliver Upton <oupton@google.com>
Cc: Shaohua Li <shli@fb.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Wang Qing <wangqing@vivo.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 00b151f2

Documentation/admin-guide/mm/pagemap.rst

+2 −0
Original line number Diff line number Diff line
@@ -21,6 +21,8 @@ There are four components to pagemap: 
    * Bit  55    pte is soft-dirty (see

      :ref:`Documentation/admin-guide/mm/soft-dirty.rst <soft_dirty>`)

    * Bit  56    page exclusively mapped (since 4.2)

    * Bit  57    pte is uffd-wp write-protected (since 5.13) (see

      :ref:`Documentation/admin-guide/mm/userfaultfd.rst <userfaultfd>`)

    * Bits 57-60 zero

    * Bit  61    page is file-page or shared-anon (since 3.5)

    * Bit  62    page swapped

fs/proc/task_mmu.c

+9 −0
Original line number Diff line number Diff line
@@ -1302,6 +1302,7 @@ struct pagemapread { 
#define PM_PFRAME_MASK		GENMASK_ULL(PM_PFRAME_BITS - 1, 0)

#define PM_SOFT_DIRTY		BIT_ULL(55)

#define PM_MMAP_EXCLUSIVE	BIT_ULL(56)

#define PM_UFFD_WP		BIT_ULL(57)

#define PM_FILE			BIT_ULL(61)

#define PM_SWAP			BIT_ULL(62)

#define PM_PRESENT		BIT_ULL(63)
@@ -1375,10 +1376,14 @@ static pagemap_entry_t pte_to_pagemap_entry(struct pagemapread *pm, 
		page = vm_normal_page(vma, addr, pte);

		if (pte_soft_dirty(pte))

			flags |= PM_SOFT_DIRTY;

		if (pte_uffd_wp(pte))

			flags |= PM_UFFD_WP;

	} else if (is_swap_pte(pte)) {

		swp_entry_t entry;

		if (pte_swp_soft_dirty(pte))

			flags |= PM_SOFT_DIRTY;

		if (pte_swp_uffd_wp(pte))

			flags |= PM_UFFD_WP;

		entry = pte_to_swp_entry(pte);

		if (pm->show_pfn)

			frame = swp_type(entry) |
@@ -1426,6 +1431,8 @@ static int pagemap_pmd_range(pmd_t *pmdp, unsigned long addr, unsigned long end, 
			flags |= PM_PRESENT;

			if (pmd_soft_dirty(pmd))

				flags |= PM_SOFT_DIRTY;

			if (pmd_uffd_wp(pmd))

				flags |= PM_UFFD_WP;

			if (pm->show_pfn)

				frame = pmd_pfn(pmd) +

					((addr & ~PMD_MASK) >> PAGE_SHIFT);
@@ -1444,6 +1451,8 @@ static int pagemap_pmd_range(pmd_t *pmdp, unsigned long addr, unsigned long end, 
			flags |= PM_SWAP;

			if (pmd_swp_soft_dirty(pmd))

				flags |= PM_SOFT_DIRTY;

			if (pmd_swp_uffd_wp(pmd))

				flags |= PM_UFFD_WP;

			VM_BUG_ON(!is_pmd_migration_entry(pmd));

			page = migration_entry_to_page(entry);

		}