From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1948117AbcBRUXI (ORCPT ); Thu, 18 Feb 2016 15:23:08 -0500 Received: from terminus.zytor.com ([198.137.202.10]:47039 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1947284AbcBRUXE (ORCPT ); Thu, 18 Feb 2016 15:23:04 -0500 Date: Thu, 18 Feb 2016 12:21:30 -0800 From: tip-bot for Dave Hansen Message-ID: Cc: aneesh.kumar@linux.vnet.ibm.com, dvlasenk@redhat.com, jason.low2@hp.com, bp@alien8.de, torvalds@linux-foundation.org, dan.j.williams@intel.com, riel@redhat.com, dave@sr71.net, kirill.shutemov@linux.intel.com, akpm@linux-foundation.org, hpa@zytor.com, linux-kernel@vger.kernel.org, brgerst@gmail.com, luto@amacapital.net, dave.hansen@linux.intel.com, sasha.levin@oracle.com, dingel@linux.vnet.ibm.com, peterz@infradead.org, tglx@linutronix.de, mingo@kernel.org, emunson@akamai.com Reply-To: tglx@linutronix.de, mingo@kernel.org, dave.hansen@linux.intel.com, peterz@infradead.org, dingel@linux.vnet.ibm.com, sasha.levin@oracle.com, emunson@akamai.com, hpa@zytor.com, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, kirill.shutemov@linux.intel.com, brgerst@gmail.com, luto@amacapital.net, torvalds@linux-foundation.org, dan.j.williams@intel.com, dave@sr71.net, riel@redhat.com, aneesh.kumar@linux.vnet.ibm.com, dvlasenk@redhat.com, bp@alien8.de, jason.low2@hp.com In-Reply-To: <20160212210216.C3824032@viggo.jf.intel.com> References: <20160212210216.C3824032@viggo.jf.intel.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:mm/pkeys] mm/gup: Factor out VMA fault permission checking Git-Commit-ID: d4925e00d59698a201231cf99dce47d8b922bb34 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: d4925e00d59698a201231cf99dce47d8b922bb34 Gitweb: http://git.kernel.org/tip/d4925e00d59698a201231cf99dce47d8b922bb34 Author: Dave Hansen AuthorDate: Fri, 12 Feb 2016 13:02:16 -0800 Committer: Ingo Molnar CommitDate: Thu, 18 Feb 2016 09:32:43 +0100 mm/gup: Factor out VMA fault permission checking This code matches a fault condition up with the VMA and ensures that the VMA allows the fault to be handled instead of just erroring out. We will be extending this in a moment to comprehend protection keys. Signed-off-by: Dave Hansen Reviewed-by: Thomas Gleixner Cc: Andrew Morton Cc: Andy Lutomirski Cc: Aneesh Kumar K.V Cc: Borislav Petkov Cc: Brian Gerst Cc: Dan Williams Cc: Dave Hansen Cc: Denys Vlasenko Cc: Dominik Dingel Cc: Eric B Munson Cc: H. Peter Anvin Cc: Jason Low Cc: Kirill A. Shutemov Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Rik van Riel Cc: Sasha Levin Cc: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/20160212210216.C3824032@viggo.jf.intel.com Signed-off-by: Ingo Molnar --- mm/gup.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) diff --git a/mm/gup.c b/mm/gup.c index de24ef4..b935c2c 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -610,6 +610,18 @@ next_page: } EXPORT_SYMBOL(__get_user_pages); +bool vma_permits_fault(struct vm_area_struct *vma, unsigned int fault_flags) +{ + vm_flags_t vm_flags; + + vm_flags = (fault_flags & FAULT_FLAG_WRITE) ? VM_WRITE : VM_READ; + + if (!(vm_flags & vma->vm_flags)) + return false; + + return true; +} + /* * fixup_user_fault() - manually resolve a user page fault * @tsk: the task_struct to use for page fault accounting, or @@ -645,7 +657,6 @@ int fixup_user_fault(struct task_struct *tsk, struct mm_struct *mm, bool *unlocked) { struct vm_area_struct *vma; - vm_flags_t vm_flags; int ret, major = 0; if (unlocked) @@ -656,8 +667,7 @@ retry: if (!vma || address < vma->vm_start) return -EFAULT; - vm_flags = (fault_flags & FAULT_FLAG_WRITE) ? VM_WRITE : VM_READ; - if (!(vm_flags & vma->vm_flags)) + if (!vma_permits_fault(vma, fault_flags)) return -EFAULT; ret = handle_mm_fault(mm, vma, address, fault_flags);