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=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 65D0DC432C0 for ; Tue, 19 Nov 2019 19:35:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3E03D2186D for ; Tue, 19 Nov 2019 19:35:40 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ti.com header.i=@ti.com header.b="qUWKigK0" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727194AbfKSTfj (ORCPT ); Tue, 19 Nov 2019 14:35:39 -0500 Received: from lelv0142.ext.ti.com ([198.47.23.249]:36476 "EHLO lelv0142.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726874AbfKSTfi (ORCPT ); Tue, 19 Nov 2019 14:35:38 -0500 Received: from fllv0034.itg.ti.com ([10.64.40.246]) by lelv0142.ext.ti.com (8.15.2/8.15.2) with ESMTP id xAJJZVAc002625; Tue, 19 Nov 2019 13:35:31 -0600 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1574192132; bh=k7VUJ7xrx8aTdO9PAjjAXV0s8KEMOCX5ocuWvOEy3kQ=; h=Subject:To:CC:References:From:Date:In-Reply-To; b=qUWKigK0UMF3+rWwYbdbEBNKfu/SUf3VNN4qKfMgWICXlhvjJ4lkkIJMEWXBRWGjY CSDjRaGkbh6PZa3Jp9rsDjt7iXFkvSuXQU2F6B4NWtrzsCsbyUyGWi5Q9tsm06rz+D L5WU4fcDp4E+ZHtfTOneEKMzDTec4z8NqABNiz3I= Received: from DFLE104.ent.ti.com (dfle104.ent.ti.com [10.64.6.25]) by fllv0034.itg.ti.com (8.15.2/8.15.2) with ESMTPS id xAJJZVi3062807 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=FAIL); Tue, 19 Nov 2019 13:35:31 -0600 Received: from DFLE104.ent.ti.com (10.64.6.25) by DFLE104.ent.ti.com (10.64.6.25) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1847.3; Tue, 19 Nov 2019 13:35:31 -0600 Received: from fllv0039.itg.ti.com (10.64.41.19) by DFLE104.ent.ti.com (10.64.6.25) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1847.3 via Frontend Transport; Tue, 19 Nov 2019 13:35:31 -0600 Received: from [10.250.45.147] (ileax41-snat.itg.ti.com [10.172.224.153]) by fllv0039.itg.ti.com (8.15.2/8.15.2) with ESMTP id xAJJZV3T053631; Tue, 19 Nov 2019 13:35:31 -0600 Subject: Re: [PATCH] ARM: OMAP: Use ARM SMC Calling Convention when OP-TEE is available To: Tony Lindgren CC: Mark Rutland , , References: <29db708e-119e-8a89-7d43-e38e2a10dc07@ti.com> <20191119162157.GJ35479@atomide.com> <6e009ae3-6aa2-409b-749f-4947303940d8@ti.com> <20191119164227.GL35479@atomide.com> <20191119180546.GM35479@atomide.com> <9e15c170-c9fa-778c-d998-bd1111a6390d@ti.com> <20191119183247.GN35479@atomide.com> <20191119190721.GO35479@atomide.com> <7fa11037-8d33-2274-c8cc-80e9630b38b0@ti.com> <20191119192029.GP35479@atomide.com> From: "Andrew F. Davis" Message-ID: <0ad31b32-712e-5bef-5645-0336dfec99cc@ti.com> Date: Tue, 19 Nov 2019 14:35:26 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <20191119192029.GP35479@atomide.com> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/19/19 2:20 PM, Tony Lindgren wrote: > * Andrew F. Davis [191119 19:13]: >> On 11/19/19 2:07 PM, Tony Lindgren wrote: >>> * Andrew F. Davis [191119 18:51]: >>>> On 11/19/19 1:32 PM, Tony Lindgren wrote: >>>>> It would allow us to completely change over to using >>>>> arm_smccc_smc() and forget the custom calls. >>>> >>>> We would need more than just the r12 quirk to replace all our custom SMC >>>> handlers, we would need quirks for omap_smc2 which puts process ID in r1 >>>> and puts #0xff in r6, and omap_smc3 that uses smc #1. All of our legacy >>>> SMC calls also trash r4-r11, that is very non SMCCC complaint as only >>>> r4-r7 need be caller saved. I don't see arm_smccc_smc() working with >>>> legacy ROM no matter how much we hack at it :( >>> >>> We would just have omap_smc2() call arm_smccc_smc() and in that >>> case. And omap_smc2() would still deal with saving and restoring >>> the registers. >> >> Then why call arm_smccc_smc()? omap_smc2() is already an assembly >> function, all it needs to do after loading the registers and saving the >> right ones is issue an "smc #0" instruction, why would we want to >> instead call into some other function to re-save registers and issue the >> exact same instruction? > > To use Linux generic API for smc calls where possible. > But we are not using generic API calls, we are using omap_smcx() which cannot call into arm_smccc_smc(). For all the above reasons plus arm_smccc_smc() uses r12 to save the stack pointer, our ROM expects r12 to store the function ID. >>> Certainly the wrapper functions calling arm_smccc_smc() can deal >>> with r12 too if the r12-quirk version and the plain version are >>> never needed the same time on a booted SoC. >>> >>> Are they ever needed the same time on a booted SoC or not? > > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > They should not be needed at the same time, either OP-TEE is on the secure side or ROM is there. Andrew > Sorry but maybe check the font size on your screen. I'm trying to > get your attention again for the second time above to answer a > question I asked. > >>>> I can make OP-TEE also compatible with the r12 quirk, which is what I >>>> used to do. That way we didn't need to do any detection. The issue was >>>> that non-standard SMC calls should not go through the common SMCCC >>>> handler (unless you are QCOM for some reason..). >>> >>> Sounds like for optee nothing must be done for r12 :) > >> Unless all our calls use the r12 hack, then we would need to fixup >> OP-TEE to accept that also. > > No idea about that that part, but sounds like r12 use is up to > the caller in the optee case. > > Regards, > > Tony >