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.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (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 D106BC433F5 for ; Tue, 1 Feb 2022 07:45:28 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4Jnxml1TV8z3bZT for ; Tue, 1 Feb 2022 18:45:27 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=none (no SPF record) smtp.mailfrom=lst.de (client-ip=213.95.11.211; helo=verein.lst.de; envelope-from=hch@lst.de; receiver=) Received: from verein.lst.de (verein.lst.de [213.95.11.211]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4JnxmH1RYZz2x9G for ; Tue, 1 Feb 2022 18:45:03 +1100 (AEDT) Received: by verein.lst.de (Postfix, from userid 2407) id 6C0AE68AA6; Tue, 1 Feb 2022 08:44:57 +0100 (CET) Date: Tue, 1 Feb 2022 08:44:57 +0100 From: Christoph Hellwig To: Guo Ren Subject: Re: [PATCH V4 16/17] riscv: compat: Add COMPAT Kbuild skeletal support Message-ID: <20220201074457.GC29119@lst.de> References: <20220129121728.1079364-1-guoren@kernel.org> <20220129121728.1079364-17-guoren@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Guo Ren , "open list:BROADCOM NVRAM DRIVER" , sparclinux , linux-riscv , Christoph Hellwig , linux-arch , linux-s390 , Anup Patel , the arch/x86 maintainers , linux-csky@vger.kernel.org, Christoph Hellwig , Arnd Bergmann , Linux ARM , Parisc List , Drew Fustini , Greg Kroah-Hartman , Wang Junqiang , Linux Kernel Mailing List , Palmer Dabbelt , liush , linuxppc-dev , Wei Fu Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Mon, Jan 31, 2022 at 09:50:58PM +0800, Guo Ren wrote: > On Mon, Jan 31, 2022 at 8:26 PM Christoph Hellwig wrote: > > > > Given that most rv64 implementations can't run in rv32 mode, what is the > > failure mode if someone tries it with the compat mode enabled? > A static linked simple hello_world could still run on a non-compat > support hardware. But most rv32 apps would meet different userspace > segment faults. > > Current code would let the machine try the rv32 apps without detecting > whether hw support or not. Hmm, we probably want some kind of check for not even offer running rv32 binaries. I guess trying to write UXL some time during early boot and catching the resulting exception would be the way to go? > > > -- > Best Regards > Guo Ren > > ML: https://lore.kernel.org/linux-csky/ ---end quoted text---