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 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 2E4E1C433EF for ; Wed, 20 Apr 2022 19:53:40 +0000 (UTC) Received: from localhost ([::1]:38874 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nhGOR-0003lf-BZ for qemu-devel@archiver.kernel.org; Wed, 20 Apr 2022 15:53:39 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:40964) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nhFwO-0005tF-V0 for qemu-devel@nongnu.org; Wed, 20 Apr 2022 15:24:41 -0400 Received: from mail-yb1-xb2d.google.com ([2607:f8b0:4864:20::b2d]:42917) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1nhFwM-0004Py-OA for qemu-devel@nongnu.org; Wed, 20 Apr 2022 15:24:40 -0400 Received: by mail-yb1-xb2d.google.com with SMTP id p65so4675722ybp.9 for ; Wed, 20 Apr 2022 12:24:38 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=6QnCp7s5TAfHx/fjg0yOfJlJk1IPDAIRJ2VTwMwdcps=; b=szebIxfY5tNO8N1rVtr2fI2cZyLQuuRxWoTV6kVeIv34hfoRy9u2BUEBtNZwX9toR0 RCevBsAGSPTVSildhDXiQrNotBEjh6zQEz0jSXSYe8M5OsDhuu1fccLnxXjsKCBhlYKN 6pVGM+TGndopUybogbvATXM/PhmHgC21ekwrYroYN+vTExKyyQsZpafU1GluGXVhD25+ bcUAko9RnGxZFl0ImJIOV1LZ5DEG5LGXr7nyX4/h9sgTZDehkI2H57YKNGLQOEC/Qh+p AHh2M/iI2XKaAtU6Y1/D13ApQ9+MRvyeRJ5/Nx8820nPogNyQQOAaitKxra0sI9p1aim n7ag== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=6QnCp7s5TAfHx/fjg0yOfJlJk1IPDAIRJ2VTwMwdcps=; b=fke//U2WVxqik0cnyQ4XQYVUCtxMDaZgvL1KODblmjGSn6fL74m6x+F3N+fuAZ+LLl 8xrV04j1XCvUVffE8djehBXovClcGENjseBGbWRu76uIU1N86GHqnYUmHFGeD8MA6xAT 3c+dBptHGNVN9zkbk0MvuPawrKpbd4pD8KohHV07wT3ic1UhyuAvIBjlJlmwQvsjgPcw kUF0FM6d29gkTl1Hbuo0lwzI4B/DXlDf/zhUKzt7Pwy9F7QRWThd8yloaw+jUcqfhk2l jhkvUVj4GLA1Fvthfn2sQfxw4Aa9z30SNeo0CFOUyOlQDqYgZBf7ELpKQGpvrY3WV1F9 Txtw== X-Gm-Message-State: AOAM533XgQVb8DNH2cw/nZwGy9nnKlg7Eghay/insf1Ul5JHvacdIqYk s+Bo8H8aSxppkjSbe/vtbeEsZdw6007kaVqiivbJZg== X-Google-Smtp-Source: ABdhPJwKmaKdksNnk3kWKdD6J1a3xbIIFyYvyWgNYQIoWNhA4xctKK7lGXgBCFsqYeMeYuWuROrHx32bEmz7LzUhqhg= X-Received: by 2002:a25:3b55:0:b0:641:bd5:e3fa with SMTP id i82-20020a253b55000000b006410bd5e3famr21360135yba.193.1650482677568; Wed, 20 Apr 2022 12:24:37 -0700 (PDT) MIME-Version: 1.0 References: <20220418191100.270334-1-leandro.lupori@eldorado.org.br> <20220418191100.270334-2-leandro.lupori@eldorado.org.br> <5a99283a-8d7c-e6d5-30fd-b148a2b59ead@eldorado.org.br> In-Reply-To: <5a99283a-8d7c-e6d5-30fd-b148a2b59ead@eldorado.org.br> From: Peter Maydell Date: Wed, 20 Apr 2022 20:24:26 +0100 Message-ID: Subject: Re: [RFC PATCH v3 1/5] ppc64: Add semihosting support To: Leandro Lupori Content-Type: text/plain; charset="UTF-8" Received-SPF: pass client-ip=2607:f8b0:4864:20::b2d; envelope-from=peter.maydell@linaro.org; helo=mail-yb1-xb2d.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: danielhb413@gmail.com, richard.henderson@linaro.org, qemu-devel@nongnu.org, groug@kaod.org, qemu-ppc@nongnu.org, clg@kaod.org, pbonzini@redhat.com, alex.bennee@linaro.org, david@gibson.dropbear.id.au Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Wed, 20 Apr 2022 at 19:20, Leandro Lupori wrote: > > On 4/19/22 06:26, Peter Maydell wrote: > > On Mon, 18 Apr 2022 at 20:15, Leandro Lupori > > wrote: > >> > >> Add semihosting support for PPC64. This implementation is > >> based on the standard for ARM semihosting version 2.0, as > >> implemented by QEMU and documented in > >> > >> https://github.com/ARM-software/abi-aa/releases > >> > >> The PPC64 specific differences are the following: > >> > >> Semihosting Trap Instruction: sc 7 > >> Operation Number Register: r3 > >> Parameter Register: r4 > >> Return Register: r3 > >> Data block field size: 64 bits > > > > Where is the independent specification which defines that > > this is the ABI for PPC semihosting? You should provide the > > URL for that in a comment somewhere. > > > > AFAIK, there is no official PPC semihosting specification. Would it be > ok to just document it somewhere else, e.g. GitHub, as an unofficial > specification? I'm going to push back on this in the same way I did for the RISC-V folks. If this is an official PPC semihosting specification, intended to be supported by multiple different pieces of software, it needs to have an independent spec document somewhere (even if that spec document just cross-refers to the Arm spec for most of the detail). If this is an ad-hoc "add this thing for PPC in a purely QEMU-specific way" patchset, then no, we shouldn't implement it. Semihosting is an ABI, and when QEMU implements an ABI it should be because it's an external pre-existing one. thanks -- PMM