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=-2.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, 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 30AD3C3A5A7 for ; Tue, 3 Sep 2019 07:38:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0646422DBF for ; Tue, 3 Sep 2019 07:38:57 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="ZWYwkcS/" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728198AbfICHi4 (ORCPT ); Tue, 3 Sep 2019 03:38:56 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:54488 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728045AbfICHiv (ORCPT ); Tue, 3 Sep 2019 03:38:51 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Transfer-Encoding :Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Sender:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help: List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=zMlhPvXbFRvudQ4Wa6rXBHMxB5a9svwnPxE7oMqO/UQ=; b=ZWYwkcS/DNQwcA/qB3ONLZ/EdM RIbDgQlzzAAy3fBP7PQ9X8hhQug0ul1bPw7yDwcqWGWDfyysfvCi6BI4LG/+Nx+kzfEtGiule0IYI uQNtvGDz2UTuocqdY4R3CiflvMfmTyBqXzuCz1K+Fk52aCVt+lHwQMx1kDdHXJ2s7f9lGUdZMwiLr v+K5G5U9AdwZzbYzkFAHEnN/in6HWsGHer1nItvPZvYF8hnk/9ckLXHlWX6LHFA1iV+aD4YMf5DwZ EPMm53+f2taQ8DH7n6FIozM2TH2rCVag6JvRGmxyow+At8Wwo9QDIe+Hmp8mW5a57nCBCaK4ITWEt PK0LgQgw==; Received: from hch by bombadil.infradead.org with local (Exim 4.92 #3 (Red Hat Linux)) id 1i53On-0002SC-Nm; Tue, 03 Sep 2019 07:38:45 +0000 Date: Tue, 3 Sep 2019 00:38:45 -0700 From: "hch@infradead.org" To: Atish Patra Cc: "hch@infradead.org" , "aou@eecs.berkeley.edu" , "alankao@andestech.com" , "gregkh@linuxfoundation.org" , "anup@brainfault.org" , "palmer@sifive.com" , "linux-kernel@vger.kernel.org" , "rppt@linux.ibm.com" , "alexios.zavras@intel.com" , "gary@garyguo.net" , "paul.walmsley@sifive.com" , "linux-riscv@lists.infradead.org" , "tglx@linutronix.de" Subject: Re: [RFC PATCH 0/2] Add support for SBI version to 0.2 Message-ID: <20190903073845.GA1170@infradead.org> References: <20190826233256.32383-1-atish.patra@wdc.com> <20190827144624.GA18535@infradead.org> <20190829105919.GB8968@infradead.org> <4bd0a62ba36587661574e1bf8b094b0a28ec8941.camel@wdc.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <4bd0a62ba36587661574e1bf8b094b0a28ec8941.camel@wdc.com> User-Agent: Mutt/1.11.4 (2019-03-13) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Aug 30, 2019 at 11:13:25PM +0000, Atish Patra wrote: > If I understood you clearly, you want to call it legacy in the spec and > just say v0.1 extensions. > > The whole idea of marking them as legacy extensions to indicate that it > would be obsolete in the future. > > But I am not too worried about the semantics here. So I am fine with > just changing the text to v0.1 if that avoids confusion. So my main problems is that we are lumping all the "legacy" extensions together. While some of them are simply a bad idea and shouldn't really be implemented for anything new ever, others like the sfence.vma and ipi ones are needed until we have hardware support to avoid them and possibly forever for virtualization. So either we use different markers of legacy for them, or we at least define new extensions that replace them at the same time. What I want to avoid is the possibŃ–ly of an implementation using the really legacy bits and new extensions at the same time.