From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754786AbbLDBOv (ORCPT ); Thu, 3 Dec 2015 20:14:51 -0500 Received: from mga14.intel.com ([192.55.52.115]:51335 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754728AbbLDBOq (ORCPT ); Thu, 3 Dec 2015 20:14:46 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.20,378,1444719600"; d="scan'208";a="833926413" Subject: [PATCH 15/34] mm: factor out VMA fault permission checking To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, x86@kernel.org, Dave Hansen , dave.hansen@linux.intel.com From: Dave Hansen Date: Thu, 03 Dec 2015 17:14:45 -0800 References: <20151204011424.8A36E365@viggo.jf.intel.com> In-Reply-To: <20151204011424.8A36E365@viggo.jf.intel.com> Message-Id: <20151204011445.19B1F2B3@viggo.jf.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Dave Hansen 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 --- b/mm/gup.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) diff -puN mm/gup.c~pkeys-10-pte-fault mm/gup.c --- a/mm/gup.c~pkeys-10-pte-fault 2015-12-03 16:21:24.737630991 -0800 +++ b/mm/gup.c 2015-12-03 16:21:24.741631172 -0800 @@ -557,6 +557,18 @@ 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 @@ -588,15 +600,13 @@ int fixup_user_fault(struct task_struct unsigned long address, unsigned int fault_flags) { struct vm_area_struct *vma; - vm_flags_t vm_flags; int ret; vma = find_extend_vma(mm, address); 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); _ From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f50.google.com (mail-pa0-f50.google.com [209.85.220.50]) by kanga.kvack.org (Postfix) with ESMTP id A297D82F64 for ; Thu, 3 Dec 2015 20:14:59 -0500 (EST) Received: by pacwq6 with SMTP id wq6so555823pac.1 for ; Thu, 03 Dec 2015 17:14:59 -0800 (PST) Received: from mga01.intel.com (mga01.intel.com. [192.55.52.88]) by mx.google.com with ESMTP id q62si15484388pfq.5.2015.12.03.17.14.45 for ; Thu, 03 Dec 2015 17:14:46 -0800 (PST) Subject: [PATCH 15/34] mm: factor out VMA fault permission checking From: Dave Hansen Date: Thu, 03 Dec 2015 17:14:45 -0800 References: <20151204011424.8A36E365@viggo.jf.intel.com> In-Reply-To: <20151204011424.8A36E365@viggo.jf.intel.com> Message-Id: <20151204011445.19B1F2B3@viggo.jf.intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, x86@kernel.org, Dave Hansen , dave.hansen@linux.intel.com From: Dave Hansen 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 --- b/mm/gup.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) diff -puN mm/gup.c~pkeys-10-pte-fault mm/gup.c --- a/mm/gup.c~pkeys-10-pte-fault 2015-12-03 16:21:24.737630991 -0800 +++ b/mm/gup.c 2015-12-03 16:21:24.741631172 -0800 @@ -557,6 +557,18 @@ 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 @@ -588,15 +600,13 @@ int fixup_user_fault(struct task_struct unsigned long address, unsigned int fault_flags) { struct vm_area_struct *vma; - vm_flags_t vm_flags; int ret; vma = find_extend_vma(mm, address); 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); _ -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org