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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 3D667C433F5 for ; Mon, 16 May 2022 10:31:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=mGx3W5b11jd1i74YuyATCbDxXiJbTLT0t5Hf2UciUUs=; b=s0xIbkh3aN3CUX Cr9UvmGRvdJMp6K27J5MhV4xQUFpFUjnLkuRUi9b4BHGfHd4VLzlbdRmeX+Thj8tcgDW4yVV/ixoD 14TvDQCFkw49w5R44nbqI3yYuHD4t0Zeyb+8NxG/X5kxmbkaQkpO5Q4gcr3+UfUEyiKDghcQtm5bg u6n2nRWVj1ZdzNCNIw1iT3tiEFqbYTd2VFFAlMQjzF2Z1Z1zw2uJj7fu17hkso5FNAmy4iumwzk+G 0Yd1dwMy/yJLQorO1l/l3eCi71O3tI+2owm/maAOijljdwUS9xr3MyhktKR0lqKYrRKjaEuQnDa+R 2yGijv/+wv4MRGIVLOFw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nqY0R-0077Kq-LN; Mon, 16 May 2022 10:31:15 +0000 Received: from gloria.sntech.de ([185.11.138.130]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nqY0P-0077KE-OL for linux-riscv@lists.infradead.org; Mon, 16 May 2022 10:31:15 +0000 Received: from ip5b412258.dynamic.kabel-deutschland.de ([91.65.34.88] helo=diego.localnet) by gloria.sntech.de with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1nqY08-0001ig-KU; Mon, 16 May 2022 12:30:56 +0200 From: Heiko =?ISO-8859-1?Q?St=FCbner?= To: Christoph Hellwig , Philipp Tomsich Cc: palmer@dabbelt.com, paul.walmsley@sifive.com, aou@eecs.berkeley.edu, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, wefu@redhat.com, liush@allwinnertech.com, guoren@kernel.org, atishp@atishpatra.org, anup@brainfault.org, drew@beagleboard.org, arnd@arndb.de, wens@csie.org, maxime@cerno.tech, gfavor@ventanamicro.com, andrea.mondelli@huawei.com, behrensj@mit.edu, xinhaoqu@huawei.com, mick@ics.forth.gr, allen.baum@esperantotech.com, jscheid@ventanamicro.com, rtrauben@gmail.com, samuel@sholland.org, cmuellner@linux.com, Wei Wu , Daniel Lustig , Bill Huffman Subject: Re: [PATCH 09/12] riscv: add RISC-V Svpbmt extension support Date: Mon, 16 May 2022 12:30:55 +0200 Message-ID: <4710483.GXAFRqVoOG@diego> In-Reply-To: References: <20220511192921.2223629-1-heiko@sntech.de> <20220516061057.GL12339@lst.de> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220516_033113_842741_3BE80AB2 X-CRM114-Status: GOOD ( 24.79 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org Am Montag, 16. Mai 2022, 11:09:12 CEST schrieb Philipp Tomsich: > On Mon, 16 May 2022 at 08:11, Christoph Hellwig wrote: > > > > > +config RISCV_ISA_SVPBMT > > > + bool "SVPBMT extension support" > > > > I don't think this prompt is very useful as it doesn't describe > > what it does. But do we even want people to disable it as it is > > really essentially for a fully functioning kernel and a pity that > > it took RISC-V so long to get there? > > Given that RISC-V is (in some ways) an ISA construction set, there > will be valid use cases for embedded users to disable this (e.g. if > they have their own non-standard way to configure these). So while > kernels for binary distributions (and desktop, server, or > general-purpose embedded) will always enable these, I would fully > expect some users to want to turn these off. Also, enabling the SVPBMT extension will pull in the alternative-patching as well of course, and having a way to disable that was a review-request a version in the past. > @Heiko: I would request that we have a longer help text on this, which > explains what it is and ends with the usual "When in doubt, say Y." ok, will do > > > + depends on 64BIT && MMU > > > + select RISCV_ALTERNATIVE > > > + default y > > > + help > > > + Adds support to dynamically detect the presence of the SVPBMT extension > > > > overly long line here. will fix together with Philipp's help-text wish > > > index 5f1046e82d9f..dbfcd9b72bd8 100644 > > > --- a/arch/riscv/include/asm/errata_list.h > > > +++ b/arch/riscv/include/asm/errata_list.h > > > @@ -14,6 +14,9 @@ > > > #define ERRATA_SIFIVE_NUMBER 2 > > > #endif > > > > > > +#define CPUFEATURE_SVPBMT 0 > > > +#define CPUFEATURE_NUMBER 1 > > > > is errata_list.h really the right place for architectural features? That probably stems from the alternatives being exclusively used for erratas in the past. I guess making this "alternative-list.h" might be a better naming? Or are there even better suggestions? > > Otherwise looks good: > > > > Reviewed-by: Christoph Hellwig Thanks Heiko _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv