From 5c9d2d5c269c498aa9a546e8d2158a3e4142a1a2 Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Wed, 29 Nov 2017 16:10:21 -0800 Subject: [PATCH] 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/gup.c | 2 +- mm/hmm.c | 4 ++-- mm/memory.c | 4 ++-- 3 files changed, 5 insertions(+), 5 deletions(-) diff --git a/mm/gup.c b/mm/gup.c index dfcde13f289a..85cc822fd403 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -66,7 +66,7 @@ static int follow_pfn_pte(struct vm_area_struct *vma, unsigned long address, */ static inline bool can_follow_write_pte(pte_t pte, unsigned int flags) { - return pte_write(pte) || + return pte_access_permitted(pte, WRITE) || ((flags & FOLL_FORCE) && (flags & FOLL_COW) && pte_dirty(pte)); } diff --git a/mm/hmm.c b/mm/hmm.c index 93718a391611..3a5c172af560 100644 --- a/mm/hmm.c +++ b/mm/hmm.c @@ -456,11 +456,11 @@ static int hmm_vma_walk_pmd(pmd_t *pmdp, continue; } - if (write_fault && !pte_write(pte)) + if (!pte_access_permitted(pte, write_fault)) goto fault; pfns[i] = hmm_pfn_t_from_pfn(pte_pfn(pte)) | flag; - pfns[i] |= pte_write(pte) ? HMM_PFN_WRITE : 0; + pfns[i] |= pte_access_permitted(pte, WRITE) ? HMM_PFN_WRITE : 0; continue; fault: 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)); -- GitLab