From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.7 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 135B7ECDE47 for ; Thu, 8 Nov 2018 14:48:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CB6972081D for ; Thu, 8 Nov 2018 14:48:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="DgjzYi78" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CB6972081D Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727848AbeKIAYD (ORCPT ); Thu, 8 Nov 2018 19:24:03 -0500 Received: from mail-it1-f193.google.com ([209.85.166.193]:54296 "EHLO mail-it1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726929AbeKIAYC (ORCPT ); Thu, 8 Nov 2018 19:24:02 -0500 Received: by mail-it1-f193.google.com with SMTP id d6so1873534itl.4 for ; Thu, 08 Nov 2018 06:48:12 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=UT2LNLgTHTkAKpTXl4DqZJH7JJqcSLLb7Ngoy3nD7IY=; b=DgjzYi78G7HfWfbIMYpQpW/YmlvU4aWzlH//oD5cqPFf0HEQ1Ff674iUdBEmkPEQFd H0RSFkVg6ZBJ7jVMEiXdnBOBLTF9zV5wDiIlwImEScnQ73lVmb+R3GTakfk/uDPlg85x 8rgULTX+5erC9B04Fkfd1tgOy00WDbBLwKmfayRQDIwkSpcCUXAS1ccagbrg0cebcLUz Nrc2wCyQKGeR6COkeS4oBeGR+TrMQzV8WRv6Pz3ppPniftBkWsqZz/tbmHaIvdS+TuHw 7RIwu4pevidwkzsJxSDYSvWV4wE8K1+M8fHjZ3v+gAkVbS8psklrSd0OxMtKG2b1aL7n CBlA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=UT2LNLgTHTkAKpTXl4DqZJH7JJqcSLLb7Ngoy3nD7IY=; b=ofn0aGSDCEm56VIYyMvLymviHGNOOpVqjH4ngWCg22SD8XM05xltraRjgqHJGh1Oy9 7eaIo2DgGm361pFsYm5uJfakkle6B8mlIvAcjsnq0aCASABiBoRwonObJYuPBZIMDxyQ lwyignVp5xFw7RsHvYgiVP984oRXZeCmJYgcTF/ER2BZrnU8b86/Efl16p9JngrAzTSg 3/u7Umdp2YfJrrc30bOeavOdLtPF8Y5MQ09wFY3DQ27exX3MbrzSSu5RcqvvtEfppXhi vtfyGjcbLBRq47xM67EDDT5r9+0bFmPpkPX5XhvotDllXyLwZfoSz47BpnF555nPEdlK tFlw== X-Gm-Message-State: AGRZ1gJ4Z3jPaiSZVDr9cqh5h1nykR8umS11QxZc+jbzqlnaydtadKKn jeAOkxMU78tO/ueQajj7L9qK/IqdSOjz0HJ456+OWA== X-Google-Smtp-Source: AJdET5e4Ri0qVbkbhxxVyH/nwORS8569rkWM8UCdfSxsWcrmbYX2HFdYVvkuKvsqGgZF73ovhwCo9t0TwEGI/joAh/A= X-Received: by 2002:a24:16cb:: with SMTP id a194-v6mr1189806ita.40.1541688491836; Thu, 08 Nov 2018 06:48:11 -0800 (PST) MIME-Version: 1.0 Received: by 2002:a02:1846:0:0:0:0:0 with HTTP; Thu, 8 Nov 2018 06:48:10 -0800 (PST) In-Reply-To: References: From: Andrey Konovalov Date: Thu, 8 Nov 2018 15:48:10 +0100 Message-ID: Subject: Re: [PATCH v8 0/8] arm64: untag user pointers passed to the kernel To: Catalin Marinas Cc: Will Deacon , Mark Rutland , Robin Murphy , Kees Cook , Kate Stewart , Greg Kroah-Hartman , Andrew Morton , Ingo Molnar , "Kirill A . Shutemov" , Shuah Khan , Linux ARM , "open list:DOCUMENTATION" , Linux Memory Management List , linux-arch , "open list:KERNEL SELFTEST FRAMEWORK" , LKML , Dmitry Vyukov , Kostya Serebryany , Evgeniy Stepanov , Lee Smith , Ramana Radhakrishnan , Jacob Bramley , Ruben Ayrapetyan , Chintan Pandya , Luc Van Oostenryck , Andrey Konovalov Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 8, 2018 at 3:36 PM, Andrey Konovalov wrote: [...] > Changes in v8: > - Rebased onto 65102238 (4.20-rc1). > - Added a note to the cover letter on why syscall wrappers/shims that untag > user pointers won't work. > - Added a note to the cover letter that this patchset has been merged into > the Pixel 2 kernel tree. > - Documentation fixes, in particular added a list of syscalls that don't > support tagged user pointers. Hi Catalin, I've changed the documentation to be more specific, please take a look. I haven't done anything about adding a way for the user to find out that the kernel supports this ABI extension. I don't know what would the the preferred way to do this, and we haven't received any comments on that from anybody else. Probing "on some innocuous syscall currently returning -EFAULT on tagged pointer arguments" works though, as you mentioned. As mentioned in the cover letter, this patchset has been merged into the Pixel 2 kernel tree. Thanks!