From 5c9d2d5c269c498aa9a546e8d2158a3e4142a1a2 Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Wed, 29 Nov 2017 16:10:21 -0800 Subject: mm: replace pte_write with pte_access_permitted in fault + gup paths MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The 'access_permitted' helper is used in the gup-fast path and goes beyond the simple _PAGE_RW check to also: - validate that the mapping is writable from a protection keys standpoint - validate that the pte has _PAGE_USER set since all fault paths where pte_write is must be referencing user-memory. Link: http://lkml.kernel.org/r/151043111604.2842.8051684481794973100.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams Cc: Dave Hansen Cc: Kirill A. Shutemov Cc: "Jérôme Glisse" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/memory.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'mm/memory.c') diff --git a/mm/memory.c b/mm/memory.c index 416e451a707e..4f07acd1695f 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3948,7 +3948,7 @@ static int handle_pte_fault(struct vm_fault *vmf) if (unlikely(!pte_same(*vmf->pte, entry))) goto unlock; if (vmf->flags & FAULT_FLAG_WRITE) { - if (!pte_write(entry)) + if (!pte_access_permitted(entry, WRITE)) return do_wp_page(vmf); entry = pte_mkdirty(entry); } @@ -4336,7 +4336,7 @@ int follow_phys(struct vm_area_struct *vma, goto out; pte = *ptep; - if ((flags & FOLL_WRITE) && !pte_write(pte)) + if (!pte_access_permitted(pte, flags & FOLL_WRITE)) goto unlock; *prot = pgprot_val(pte_pgprot(pte)); -- cgit v1.2.3