From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f69.google.com (mail-wm0-f69.google.com [74.125.82.69]) by kanga.kvack.org (Postfix) with ESMTP id 1DADB6B0028 for ; Tue, 27 Mar 2018 12:57:55 -0400 (EDT) Received: by mail-wm0-f69.google.com with SMTP id l23so29066wmh.1 for ; Tue, 27 Mar 2018 09:57:55 -0700 (PDT) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id w40sor902022wrc.79.2018.03.27.09.57.53 for (Google Transport Security); Tue, 27 Mar 2018 09:57:53 -0700 (PDT) From: Andrey Konovalov Subject: [RFC PATCH v2 4/6] mm, arm64: untag user addresses in mm/gup.c Date: Tue, 27 Mar 2018 18:57:40 +0200 Message-Id: In-Reply-To: References: In-Reply-To: References: Sender: owner-linux-mm@kvack.org List-ID: To: Catalin Marinas , Will Deacon , Jonathan Corbet , Mark Rutland , Robin Murphy , Al Viro , Andrey Konovalov , James Morse , Kees Cook , Bart Van Assche , Kate Stewart , Greg Kroah-Hartman , Thomas Gleixner , Philippe Ombredanne , Andrew Morton , Ingo Molnar , "Kirill A . Shutemov" , Dan Williams , "Aneesh Kumar K . V" , Zi Yan , linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: Dmitry Vyukov , Kostya Serebryany , Evgeniy Stepanov , Lee Smith , Ramana Radhakrishnan , Jacob Bramley , Ruben Ayrapetyan mm/gup.c provides a kernel interface that accepts user addresses and manipulates user pages directly (for example get_user_pages, that is used by the futex syscall). Here we also need to handle the case of tagged user pointers. Untag addresses passed to this interface. Signed-off-by: Andrey Konovalov --- mm/gup.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/mm/gup.c b/mm/gup.c index 6afae32571ca..9c4afcf50dfa 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -386,6 +386,8 @@ struct page *follow_page_mask(struct vm_area_struct *vma, struct page *page; struct mm_struct *mm = vma->vm_mm; + address = untagged_addr(address); + *page_mask = 0; /* make this handle hugepd */ @@ -647,6 +649,8 @@ static long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, if (!nr_pages) return 0; + start = untagged_addr(start); + VM_BUG_ON(!!pages != !!(gup_flags & FOLL_GET)); /* @@ -801,6 +805,8 @@ int fixup_user_fault(struct task_struct *tsk, struct mm_struct *mm, struct vm_area_struct *vma; int ret, major = 0; + address = untagged_addr(address); + if (unlocked) fault_flags |= FAULT_FLAG_ALLOW_RETRY; @@ -854,6 +860,8 @@ static __always_inline long __get_user_pages_locked(struct task_struct *tsk, long ret, pages_done; bool lock_dropped; + start = untagged_addr(start); + if (locked) { /* if VM_FAULT_RETRY can be returned, vmas become invalid */ BUG_ON(vmas); @@ -1749,6 +1757,8 @@ int __get_user_pages_fast(unsigned long start, int nr_pages, int write, unsigned long flags; int nr = 0; + start = untagged_addr(start); + start &= PAGE_MASK; addr = start; len = (unsigned long) nr_pages << PAGE_SHIFT; @@ -1801,6 +1811,8 @@ int get_user_pages_fast(unsigned long start, int nr_pages, int write, unsigned long addr, len, end; int nr = 0, ret = 0; + start = untagged_addr(start); + start &= PAGE_MASK; addr = start; len = (unsigned long) nr_pages << PAGE_SHIFT; -- 2.17.0.rc0.231.g781580f067-goog