Commit 8a13897f authored by Axel Rasmussen's avatar Axel Rasmussen Committed by Andrew Morton
Browse files

mm: userfaultfd: support UFFDIO_POISON for hugetlbfs 

The behavior here is the same as it is for anon/shmem.  This is done
separately because hugetlb pte marker handling is a bit different.

Link: https://lkml.kernel.org/r/20230707215540.2324998-6-axelrasmussen@google.com


Signed-off-by: default avatarAxel Rasmussen <axelrasmussen@google.com>
Acked-by: default avatarPeter Xu <peterx@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Brian Geffon <bgeffon@google.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Gaosheng Cui <cuigaosheng1@huawei.com>
Cc: Huang, Ying <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Houghton <jthoughton@google.com>
Cc: Jan Alexander Steffens (heftig) <heftig@archlinux.org>
Cc: Jiaqi Yan <jiaqiyan@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nadav Amit <namit@vmware.com>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suleiman Souhlal <suleiman@google.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: T.J. Alumbaugh <talumbau@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: ZhangPeng <zhangpeng362@huawei.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 597425df

mm/hugetlb.c

+19 −0
Original line number Diff line number Diff line
@@ -6262,6 +6262,25 @@ int hugetlb_mfill_atomic_pte(pte_t *dst_pte, 
	int writable;

	bool folio_in_pagecache = false;



	if (uffd_flags_mode_is(flags, MFILL_ATOMIC_POISON)) {

		ptl = huge_pte_lock(h, dst_mm, dst_pte);



		/* Don't overwrite any existing PTEs (even markers) */

		if (!huge_pte_none(huge_ptep_get(dst_pte))) {

			spin_unlock(ptl);

			return -EEXIST;

		}



		_dst_pte = make_pte_marker(PTE_MARKER_POISONED);

		set_huge_pte_at(dst_mm, dst_addr, dst_pte, _dst_pte);



		/* No need to invalidate - it was non-present before */

		update_mmu_cache(dst_vma, dst_addr, dst_pte);



		spin_unlock(ptl);

		return 0;

	}



	if (is_continue) {

		ret = -EFAULT;

		folio = filemap_lock_folio(mapping, idx);

mm/userfaultfd.c

+1 −2
Original line number Diff line number Diff line
@@ -377,8 +377,7 @@ static __always_inline ssize_t mfill_atomic_hugetlb( 
	 * by THP.  Since we can not reliably insert a zero page, this

	 * feature is not supported.

	 */

	if (uffd_flags_mode_is(flags, MFILL_ATOMIC_ZEROPAGE) ||

	    uffd_flags_mode_is(flags, MFILL_ATOMIC_POISON)) {

	if (uffd_flags_mode_is(flags, MFILL_ATOMIC_ZEROPAGE)) {

		mmap_read_unlock(dst_mm);

		return -EINVAL;

	}