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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=unavailable 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 1500EC43444 for ; Tue, 18 Dec 2018 04:18:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E3716217D7 for ; Tue, 18 Dec 2018 04:18:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726516AbeLRESY (ORCPT ); Mon, 17 Dec 2018 23:18:24 -0500 Received: from mga04.intel.com ([192.55.52.120]:65095 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726296AbeLRESY (ORCPT ); Mon, 17 Dec 2018 23:18:24 -0500 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by fmsmga104.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 17 Dec 2018 20:18:23 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,367,1539673200"; d="scan'208";a="304671402" Received: from zhangxi4-mobl5.ccr.corp.intel.com (HELO localhost) ([10.249.254.207]) by fmsmga005.fm.intel.com with ESMTP; 17 Dec 2018 20:18:16 -0800 Date: Tue, 18 Dec 2018 06:18:15 +0200 From: Jarkko Sakkinen To: Sean Christopherson Cc: Andy Lutomirski , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, Dave Hansen , Peter Zijlstra , "H. Peter Anvin" , linux-kernel@vger.kernel.org, linux-sgx@vger.kernel.org, Andy Lutomirski , Josh Triplett , Haitao Huang , Jethro Beekman , "Dr . Greg Wettstein" Subject: Re: [RFC PATCH v5 0/5] x86: Add vDSO exception fixup for SGX Message-ID: <20181218041815.GA5097@linux.intel.com> References: <20181214215729.4221-1-sean.j.christopherson@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181214215729.4221-1-sean.j.christopherson@intel.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Dec 14, 2018 at 01:57:24PM -0800, Sean Christopherson wrote: > __vdso_sgx_enter_enclave() gets another rewrite, this time to strip > it down to the bare minimum and explicitly break compliance with the > x86-64 ABI. Feedback from v4 revealed that __vdso_sgx_enter_enclave() > would need to save (a lot) more than just the non-volatile GPRs to be > compliant with the x86-64 ABI, at which point breaking from the ABI > completely became much more palatable. > > The non-standard ABI also solves the question of "which GPRs should be > marshalled to/from the enclave" by getting out of the way entirely and > letting userspace have free reign (except for RSP, which has a big ol' > DO NOT TOUCH sign on it). Can you share a reference, or is this better documented in the accompanied patches? /Jarkko