From mboxrd@z Thu Jan 1 00:00:00 1970 From: Catalin Marinas Subject: Re: [PATCH v15 00/17] arm64: untag user pointers passed to the kernel Date: Thu, 30 May 2019 18:15:40 +0100 Message-ID: <20190530171540.GD35418@arrakis.emea.arm.com> References: <20190517144931.GA56186@arrakis.emea.arm.com> <20190521182932.sm4vxweuwo5ermyd@mbp> <201905211633.6C0BF0C2@keescook> <6049844a-65f5-f513-5b58-7141588fef2b@oracle.com> <20190523201105.oifkksus4rzcwqt4@mbp> <20190524101139.36yre4af22bkvatx@mbp> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Andrey Konovalov Cc: Kees Cook , Evgenii Stepanov , Linux ARM , Linux Memory Management List , LKML , amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-rdma@vger.kernel.org, linux-media@vger.kernel.org, kvm@vger.kernel.org, "open list:KERNEL SELFTEST FRAMEWORK" , Vincenzo Frascino , Will Deacon , Mark Rutland , Andrew Morton , Greg Kroah-Hartman , Yishai Hadas , Felix Kuehling , Alexander Deucher List-Id: linux-rdma@vger.kernel.org On Tue, May 28, 2019 at 04:14:45PM +0200, Andrey Konovalov wrote: > Thanks for a lot of valuable input! I've read through all the replies > and got somewhat lost. What are the changes I need to do to this > series? > > 1. Should I move untagging for memory syscalls back to the generic > code so other arches would make use of it as well, or should I keep > the arm64 specific memory syscalls wrappers and address the comments > on that patch? Keep them generic again but make sure we get agreement with Khalid on the actual ABI implications for sparc. > 2. Should I make untagging opt-in and controlled by a command line argument? Opt-in, yes, but per task rather than kernel command line option. prctl() is a possibility of opting in. > 3. Should I "add Documentation/core-api/user-addresses.rst to describe > proper care and handling of user space pointers with untagged_addr(), > with examples based on all the cases seen so far in this series"? > Which examples specifically should it cover? I think we can leave 3 for now as not too urgent. What I'd like is for Vincenzo's TBI user ABI document to go into a more common place since we can expand it to cover both sparc and arm64. We'd need an arm64-specific doc as well for things like prctl() and later MTE that sparc may support differently. -- Catalin