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_HELO_NONE,SPF_PASS,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 60179C388F3 for ; Tue, 1 Oct 2019 05:00:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3A4012168B for ; Tue, 1 Oct 2019 05:00:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729340AbfJAE7y (ORCPT ); Tue, 1 Oct 2019 00:59:54 -0400 Received: from 59-120-53-16.HINET-IP.hinet.net ([59.120.53.16]:49896 "EHLO ATCSQR.andestech.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726157AbfJAE7x (ORCPT ); Tue, 1 Oct 2019 00:59:53 -0400 Received: from mail.andestech.com (atcpcs16.andestech.com [10.0.1.222]) by ATCSQR.andestech.com with ESMTP id x914gucI059794; Tue, 1 Oct 2019 12:42:57 +0800 (GMT-8) (envelope-from alankao@andestech.com) Received: from andestech.com (10.0.15.65) by ATCPCS16.andestech.com (10.0.1.222) with Microsoft SMTP Server id 14.3.123.3; Tue, 1 Oct 2019 12:58:15 +0800 Date: Tue, 1 Oct 2019 12:58:16 +0800 From: Alan Kao To: Atish Patra CC: "hch@infradead.org" , "linux-riscv@lists.infradead.org" , "gregkh@linuxfoundation.org" , "gary@garyguo.net" , "rppt@linux.ibm.com" , "paul.walmsley@sifive.com" , "linux-kernel@vger.kernel.org" , "aou@eecs.berkeley.edu" , "tglx@linutronix.de" , "anup@brainfault.org" , "allison@lohutok.net" , "palmer@sifive.com" Subject: Re: [PATCH v2 0/3] Add support for SBI v0.2 Message-ID: <20191001045815.GA6572@andestech.com> References: <20190927000915.31781-1-atish.patra@wdc.com> <20190927221913.GA4700@infradead.org> <8683f51f26708a468bcdf16a48db1cffac6c28d8.camel@wdc.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <8683f51f26708a468bcdf16a48db1cffac6c28d8.camel@wdc.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-Originating-IP: [10.0.15.65] X-DNSRBL: X-MAIL: ATCSQR.andestech.com x914gucI059794 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Sep 27, 2019 at 10:57:45PM +0000, Atish Patra wrote: > On Fri, 2019-09-27 at 15:19 -0700, Christoph Hellwig wrote: > > On Thu, Sep 26, 2019 at 05:09:12PM -0700, Atish Patra wrote: > > > The Supervisor Binary Interface(SBI) specification[1] now defines a > > > base extension that provides extendability to add future extensions > > > while maintaining backward compatibility with previous versions. > > > The new version is defined as 0.2 and older version is marked as > > > 0.1. > > > > > > This series adds support v0.2 and a unified calling convention > > > implementation between 0.1 and 0.2. It also adds minimal SBI > > > functions > > > from 0.2 as well to keep the series lean. > > > > So before we do this game can be please make sure we have a clean 0.2 > > environment that never uses the legacy extensions as discussed > > before? > > Without that all this work is rather futile. > > > > As per our discussion offline, here are things need to be done to > achieve that. > > 1. Replace timer, sfence and ipi with better alternative APIs > - sbi_set_timer will be same but with new calling convention > - send_ipi and sfence_* apis can be modified in such a way that > - we don't have to use unprivileged load anymore > - Make it scalable > > 2. Drop clear_ipi, console, and shutdown in 0.2. > > We will have a new kernel config (LEGACY_SBI) that can be manually > enabled if older firmware need to be used. By default, LEGACY_SBI will > be disabled and kernel with new SBI will be built. We will have to set > a flag day in a year or so when we can remove the LEGACY_SBI > completely. > > Let us know if it is not an acceptable approach to anybody. > I will post a RFC patch with new alternate v0.2 APIs sometime next > week. > Will this legacy option be compatible will bbl? says, version 1.0.0 or any earlier ones? > > _______________________________________________ > > linux-riscv mailing list > > linux-riscv@lists.infradead.org > > http://lists.infradead.org/mailman/listinfo/linux-riscv > > -- > Regards, > Atish