From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <owner-linux-mm@kvack.org>
Received: from mail-wr0-f200.google.com (mail-wr0-f200.google.com [209.85.128.200])
	by kanga.kvack.org (Postfix) with ESMTP id ACD826B0011
	for <linux-mm@kvack.org>; Thu,  3 May 2018 10:15:58 -0400 (EDT)
Received: by mail-wr0-f200.google.com with SMTP id o8-v6so11974494wra.12
        for <linux-mm@kvack.org>; Thu, 03 May 2018 07:15:58 -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 e134sor1491224wma.79.2018.05.03.07.15.57
        for <linux-mm@kvack.org>
        (Google Transport Security);
        Thu, 03 May 2018 07:15:57 -0700 (PDT)
From: Andrey Konovalov <andreyknvl@google.com>
Subject: [PATCH v2 4/6] mm, arm64: untag user addresses in mm/gup.c
Date: Thu,  3 May 2018 16:15:42 +0200
Message-Id: <24ab244adc196fda8536cf2efb59cc654e1c234b.1525356769.git.andreyknvl@google.com>
In-Reply-To: <cover.1525356769.git.andreyknvl@google.com>
References: <cover.1525356769.git.andreyknvl@google.com>
In-Reply-To: <cover.1525356769.git.andreyknvl@google.com>
References: <cover.1525356769.git.andreyknvl@google.com>
Sender: owner-linux-mm@kvack.org
List-ID: <linux-mm.kvack.org>
To: Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will.deacon@arm.com>, Jonathan Corbet <corbet@lwn.net>, Mark Rutland <mark.rutland@arm.com>, Robin Murphy <robin.murphy@arm.com>, Al Viro <viro@zeniv.linux.org.uk>, Andrey Konovalov <andreyknvl@google.com>, James Morse <james.morse@arm.com>, Kees Cook <keescook@chromium.org>, Bart Van Assche <bart.vanassche@wdc.com>, Kate Stewart <kstewart@linuxfoundation.org>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Thomas Gleixner <tglx@linutronix.de>, Philippe Ombredanne <pombredanne@nexb.com>, Andrew Morton <akpm@linux-foundation.org>, Ingo Molnar <mingo@kernel.org>, "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>, Dan Williams <dan.j.williams@intel.com>, "Aneesh Kumar K . V" <aneesh.kumar@linux.vnet.ibm.com>, Zi Yan <zi.yan@cs.rutgers.edu>, linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org
Cc: Dmitry Vyukov <dvyukov@google.com>, Kostya Serebryany <kcc@google.com>, Evgeniy Stepanov <eugenis@google.com>, Lee Smith <Lee.Smith@arm.com>, Ramana Radhakrishnan <Ramana.Radhakrishnan@arm.com>, Jacob Bramley <Jacob.Bramley@arm.com>, Ruben Ayrapetyan <Ruben.Ayrapetyan@arm.com>, Chintan Pandya <cpandya@codeaurora.org>

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.

Add untagging to gup.c functions that use user pointers for vma lookup.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 mm/gup.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/mm/gup.c b/mm/gup.c
index 76af4cfeaf68..65a9566c96d3 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -647,6 +647,8 @@ 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 +803,8 @@ 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;
 
-- 
2.17.0.441.gb46fe60e1d-goog