From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f71.google.com (mail-wm0-f71.google.com [74.125.82.71]) by kanga.kvack.org (Postfix) with ESMTP id F2D5C6B0009 for ; Fri, 9 Mar 2018 09:02:23 -0500 (EST) Received: by mail-wm0-f71.google.com with SMTP id t123so1106085wmt.2 for ; Fri, 09 Mar 2018 06:02:23 -0800 (PST) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id r185sor389201wmb.11.2018.03.09.06.02.21 for (Google Transport Security); Fri, 09 Mar 2018 06:02:22 -0800 (PST) From: Andrey Konovalov Subject: [RFC PATCH 4/6] mm, arm64: untag user addresses in mm/gup.c Date: Fri, 9 Mar 2018 15:02:02 +0100 Message-Id: In-Reply-To: References: In-Reply-To: References: Sender: owner-linux-mm@kvack.org List-ID: To: Catalin Marinas , Will Deacon , Mark Rutland , Robin Murphy , Al Viro , Philippe Ombredanne , Greg Kroah-Hartman , Thomas Gleixner , Kate Stewart , Andrew Morton , "Kirill A . Shutemov" , Ingo Molnar , "Aneesh Kumar K . V" , Minchan Kim , Michal Hocko , Shaohua Li , Andrea Arcangeli , Anshuman Khandual , Mike Rapoport , Vlastimil Babka , Naoya Horiguchi , Shakeel Butt , Joonsoo Kim , Hugh Dickins , Mel Gorman , =?UTF-8?q?J=C3=A9r=C3=B4me=20Glisse?= , Mike Kravetz , Zi Yan , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Richard Henderson , Ivan Kokshaysky , Matt Turner , Vineet Gupta , Russell King , Mark Salter , Aurelien Jacquiot , Mikael Starvik , Jesper Nilsson , Tony Luck , Fenghua Yu , Geert Uytterhoeven , James Hogan , Michal Simek , Ralf Baechle , David Howells , Ley Foon Tan , Jonas Bonn , Stefan Kristiansson , Stafford Horne , "James E . J . Bottomley" , Helge Deller , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Palmer Dabbelt , Albert Ou , Chen Liqin , Lennox Wu , Yoshinori Sato , Rich Felker , "David S . Miller" , Ingo Molnar , x86@kernel.org, Chris Zankel , Max Filippov , Arnd Bergmann , linux-alpha@vger.kernel.org, linux-snps-arc@lists.infradead.org, adi-buildroot-devel@lists.sourceforge.net, linux-c6x-dev@linux-c6x.org, linux-cris-kernel@axis.com, linux-ia64@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-metag@vger.kernel.org, linux-mips@linux-mips.org, linux-am33-list@redhat.com, nios2-dev@lists.rocketboards.org, openrisc@lists.librecores.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linux-xtensa@linux-xtensa.org, linux-arch@vger.kernel.org Cc: Dmitry Vyukov , Kostya Serebryany , Evgeniy Stepanov , Lee Smith , Ramana Radhakrishnan , Jacob Bramley , Ruben Ayrapetyan , Andrey Konovalov 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 1b46e6e74881..4d820c4792d7 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); @@ -1746,6 +1754,8 @@ 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; @@ -1798,6 +1808,8 @@ 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; -- 2.16.2.395.g2e18187dfd-goog