From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752288AbdKKUUO (ORCPT ); Sat, 11 Nov 2017 15:20:14 -0500 Received: from mga11.intel.com ([192.55.52.93]:36946 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752254AbdKKUUL (ORCPT ); Sat, 11 Nov 2017 15:20:11 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.44,379,1505804400"; d="scan'208";a="6587738" Subject: [PATCH v2 4/4] mm: replace pte_write with pte_access_permitted in fault + gup paths From: Dan Williams To: akpm@linux-foundation.org Cc: linux-nvdimm@lists.01.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Dave Hansen , =?utf-8?b?SsOpcsO0bWU=?= Glisse , "Kirill A. Shutemov" Date: Sat, 11 Nov 2017 12:11:56 -0800 Message-ID: <151043111604.2842.8051684481794973100.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <151043109403.2842.11607911965674122836.stgit@dwillia2-desk3.amr.corp.intel.com> References: <151043109403.2842.11607911965674122836.stgit@dwillia2-desk3.amr.corp.intel.com> User-Agent: StGit/0.17.1-9-g687f MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. Cc: Dave Hansen Cc: Kirill A. Shutemov Cc: "Jérôme Glisse" Signed-off-by: Dan Williams --- 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 b2b4d4263768..bb6542c47b08 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 cbdd47bf6a48..3d2e49fd851a 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 157fd4320bb3..a8cbc2c3e3c9 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3922,7 +3922,7 @@ 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); } @@ -4308,7 +4308,7 @@ 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));