Received: by 2002:a25:e7d8:0:0:0:0:0 with SMTP id e207csp3100247ybh; Mon, 16 Mar 2020 15:57:12 -0700 (PDT) X-Google-Smtp-Source: ADFU+vsPXFTvUPFQ8NN9IblgBWv6KsSizfO/XpDTeTLK2vU2Ul7DtCyb7p067a9IRtObFZkCx3V2 X-Received: by 2002:aca:b703:: with SMTP id h3mr1397710oif.148.1584399431899; Mon, 16 Mar 2020 15:57:11 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1584399431; cv=none; d=google.com; s=arc-20160816; b=SnWalF/v9RO/Dypa0eB8C6pmJNzS+oldJNYFxeeD+QRB2O4l8n6XbR2+xYKex56PoD o4Wp0XqFk4360klS+5sVVOWwybWVo9A4dbB3IAW6INIScbSljQVBbQZX/tCswjBZTcVc 8mj6eGK46B9Gqc6Ty2WxJ++dF8xplpfJvuvvyNdxkmNWPRHkTfMcNxsR3VEQEDprR0jj d5RU6Kn8vY2av+peHnmT+go5R32Gu2Z0Imbad2vGf1xvQ/z9vb0nvc8iIZILN331piLu rkuue3wYlvpYx+sO1/5AY9+VCnc2QD/mIJJcxI9k+aMhXyLYxR9FZGTObrZV9RtwBbaS xMfg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:user-agent:in-reply-to :content-disposition:mime-version:references:message-id:subject:cc :to:from:date:ironport-sdr:ironport-sdr; bh=/5ZppdtH02dfGzXOMSszQGFq5G5uVISRmRVyaifelcQ=; b=lGLFvepeF82ekuggwwb2MwJja4TPdl8Q6/VY7+WYuX/VtgfjjHtmqz58uaHfWoxtFt BfKWaHcZNQzFzACSesUo2F/hPFjGJJmaw/qjcM/dNddaxhmcp13MrOhuoM03Aeth2X12 3RM7nAE4POcXeAfn9NwtRfxETpbUJqLppXYSVHo6aM0dnXoymb9/l/0jy6SQBVNTJDCj ysqPknvlTYuK0M9F2OZkDOVY1xpemB2znwd5mfApwtw5WTZH1xIPJI+UhXHZ5ra/+F3p ltvdPkLq8MwRwjGR6V3NIGA7daP4aDj7+Rfgztzpj8IWlSgx8aZnPZdMdRvn/jK/2d6D YiOA== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=intel.com Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id l11si670511oib.32.2020.03.16.15.56.59; Mon, 16 Mar 2020 15:57:11 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=intel.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732873AbgCPWzf (ORCPT + 99 others); Mon, 16 Mar 2020 18:55:35 -0400 Received: from mga04.intel.com ([192.55.52.120]:11589 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732846AbgCPWzf (ORCPT ); Mon, 16 Mar 2020 18:55:35 -0400 IronPort-SDR: 7WkIFmFQF6Bml4R2d5RXaEdz3L9peyCD/CXyAoOIb59qfznmoAzz+biS7hlzTlWWWXQ0aPuBzJ K40W8rDf6Vqw== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Mar 2020 15:55:34 -0700 IronPort-SDR: L2UZYp09IyTg9lHguWJOyfhxMETseoQhwxC5xJdF+NWb9h4rfOEvdD0BM+3RuV3M9BjueC4pVG TqG09vv7uGLA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,561,1574150400"; d="scan'208";a="267744344" Received: from sjchrist-coffee.jf.intel.com (HELO linux.intel.com) ([10.54.74.202]) by fmsmga004.fm.intel.com with ESMTP; 16 Mar 2020 15:55:34 -0700 Date: Mon, 16 Mar 2020 15:55:34 -0700 From: Sean Christopherson To: Jethro Beekman Cc: Nathaniel McCallum , Jarkko Sakkinen , linux-kernel@vger.kernel.org, x86@kernel.org, linux-sgx@vger.kernel.org, akpm@linux-foundation.org, dave.hansen@intel.com, Neil Horman , "Huang, Haitao" , andriy.shevchenko@linux.intel.com, tglx@linutronix.de, "Svahn, Kai" , bp@alien8.de, Josh Triplett , luto@kernel.org, kai.huang@intel.com, David Rientjes , cedric.xing@intel.com, Patrick Uiterwijk , Andy Lutomirski , Connor Kuehl , Harald Hoyer , Lily Sturmann Subject: Re: [PATCH v28 21/22] x86/vdso: Implement a vDSO for Intel SGX enclave call Message-ID: <20200316225534.GK24267@linux.intel.com> References: <20200303233609.713348-1-jarkko.sakkinen@linux.intel.com> <20200303233609.713348-22-jarkko.sakkinen@linux.intel.com> <20200315012523.GC208715@linux.intel.com> <7f9f2efe-e9af-44da-6719-040600f5b351@fortanix.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <7f9f2efe-e9af-44da-6719-040600f5b351@fortanix.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 16, 2020 at 02:31:36PM +0100, Jethro Beekman wrote: > Can someone remind me why we're not passing TCS in RBX but on the stack? I finally remembered why. It's pulled off the stack and passed into the exit handler. I'm pretty sure the vDSO could take it in %rbx and manually save it on the stack, but I'd rather keep the current behavior so that the vDSO is callable from C (assuming @leaf is changed to be passed via %rcx).