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[198.145.29.99]) by mx.google.com with ESMTPS id bd11si13116715plb.184.2019.07.24.07.02.22 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 24 Jul 2019 07:02:22 -0700 (PDT) Received-SPF: pass (google.com: domain of will@kernel.org designates 198.145.29.99 as permitted sender) client-ip=198.145.29.99; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=HGjiQdK8; spf=pass (google.com: domain of will@kernel.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=will@kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: from willie-the-truck (236.31.169.217.in-addr.arpa [217.169.31.236]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0A09422BE8; Wed, 24 Jul 2019 14:02:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563976942; bh=akL4t3WLQfvH/sx6baSCdRPzrJPet6bQ0ZZAPYisZi4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=HGjiQdK87WShqPUCUDRg97LnVe6uyeIf9yy5HPpwultEhX+41Yn3D/DKXjIK8Af4f 0ygT0V9wgzsE+RPZ4QFVtqujFkiagNZGrOWFPz6QtW3TCSySYN2+CMJ5pNSGE1vClG 0S7ixJF2Qf9InXHgM9sSGPD0ag6vRkrIxQa7ibh4= Date: Wed, 24 Jul 2019 15:02:12 +0100 From: Will Deacon To: Andrey Konovalov Cc: Andrew Morton , Catalin Marinas , Mark Rutland , kvm@vger.kernel.org, Szabolcs Nagy , Will Deacon , dri-devel@lists.freedesktop.org, Kostya Serebryany , Khalid Aziz , "open list:KERNEL SELFTEST FRAMEWORK" , Felix Kuehling , Vincenzo Frascino , Jacob Bramley , Leon Romanovsky , linux-rdma@vger.kernel.org, amd-gfx@lists.freedesktop.org, Christoph Hellwig , Jason Gunthorpe , Linux ARM , Dave Martin , Evgeniy Stepanov , linux-media@vger.kernel.org, Kevin Brodsky , Kees Cook , Ruben Ayrapetyan , Ramana Radhakrishnan , Alex Williamson , Mauro Carvalho Chehab , Dmitry Vyukov , Linux Memory Management List , Greg Kroah-Hartman , Yishai Hadas , LKML , Jens Wiklander , Lee Smith , Alexander Deucher , enh , Robin Murphy , Christian Koenig , Luc Van Oostenryck Subject: Re: [PATCH v19 00/15] arm64: untag user pointers passed to the kernel Message-ID: <20190724140212.qzvbcx5j2gi5lcoj@willie-the-truck> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20170113 (1.7.2) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Hi Andrey, On Tue, Jul 23, 2019 at 08:03:29PM +0200, Andrey Konovalov wrote: > On Tue, Jul 23, 2019 at 7:59 PM Andrey Konovalov wrote: > > > > === Overview > > > > arm64 has a feature called Top Byte Ignore, which allows to embed pointer > > tags into the top byte of each pointer. Userspace programs (such as > > HWASan, a memory debugging tool [1]) might use this feature and pass > > tagged user pointers to the kernel through syscalls or other interfaces. > > > > Right now the kernel is already able to handle user faults with tagged > > pointers, due to these patches: > > > > 1. 81cddd65 ("arm64: traps: fix userspace cache maintenance emulation on a > > tagged pointer") > > 2. 7dcd9dd8 ("arm64: hw_breakpoint: fix watchpoint matching for tagged > > pointers") > > 3. 276e9327 ("arm64: entry: improve data abort handling of tagged > > pointers") > > > > This patchset extends tagged pointer support to syscall arguments. [...] > Do you think this is ready to be merged? > > Should this go through the mm or the arm tree? I would certainly prefer to take at least the arm64 bits via the arm64 tree (i.e. patches 1, 2 and 15). We also need a Documentation patch describing the new ABI. Will