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 DDCAAC54E64 for ; Tue, 26 Mar 2024 01:42:25 +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:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=yesrxLARmzKVEDoCv8d7IuP8eUZEeysVt7yAEag3ZRg=; b=yysmJLBzMOYcaF Qjc22HnouchCXF3EAxw7ipy1ZcrzK8I9gEyMrZD01zGG9Gjn4Od1GubGmyiYeDXTKwgpfPXmv41oU zEa2mfG6Fb6uneZEaCeDX6pFQh9avk9D+p9NgD7AZFS9rriSFXS4Z3VAKBee9Fpse6uNRQn3PYETH Clp6oSSnqNb8aGTfwF4wl9CJY/UGk9N2EyyZjStGi6x/rW+4VhTvKejKHVLapB4DYaRtH0mXKKEfz yotCbC+qyqmz/9f1m1Wcdqzs39px9a3SyYYLQUt+rTD6rzxyZ8t+PcYYkKw/ccR4oXWXuR8j5Wtdt JNZFtZ/dJeRpzxMVxw7w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rovpT-00000002fsJ-3XtJ; Tue, 26 Mar 2024 01:42:19 +0000 Received: from sin.source.kernel.org ([145.40.73.55]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1rovpQ-00000002fro-3Bvf for linux-riscv@lists.infradead.org; Tue, 26 Mar 2024 01:42:18 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sin.source.kernel.org (Postfix) with ESMTP id 98E7DCE1850; Tue, 26 Mar 2024 01:42:14 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E1FD2C433C7; Tue, 26 Mar 2024 01:42:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1711417333; bh=OWRGZAoTwlD15MOqhJjmQoMizKHAtbh8DHOT9VrE1lQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Ge0K347meeUSw5Cf4GUHdgcKEF+N9hl6GJfOzMa4jy+1DnbHNS+nFmpJlDxQV9Z4F e9azU+DSqzdGM4VcSCl9hwAU2NbL7fVL82sAVhASLKTGFah5GSfx6BpLHCFvz7b53V 1VIjaQV/3QZfwWXInM8YE5q/UNf1azpCW/E1M7ljohoX/Rbk/ghiEdJ+bn7h7pU6Am uGzBFD3TOCUPzjEI/6XA6h+JsV5PQNMOLOCLQH4Nn6RFYwEXVF2H2MhhYSCCAX14Xs SXCHYkUyyBzWiBVPx1kuXgEl6YZG591UGkJ/u/ZYzY4fo9mt7inhSI/C56d4JrsyY/ mpgAV2lI4B0Jg== Date: Tue, 26 Mar 2024 09:28:58 +0800 From: Jisheng Zhang To: Bo Gan Cc: Paul Walmsley , Palmer Dabbelt , Albert Ou , Daniel Lezcano , Thomas Gleixner , linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, Samuel Holland Subject: Re: [PATCH 1/5] riscv: nommu: remove PAGE_OFFSET hardcoding Message-ID: References: <20240325164021.3229-1-jszhang@kernel.org> <20240325164021.3229-2-jszhang@kernel.org> <37d456c1-f0bd-1a78-2d0c-350ca25c6b8d@gmail.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <37d456c1-f0bd-1a78-2d0c-350ca25c6b8d@gmail.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240325_184217_030499_77E151B6 X-CRM114-Status: GOOD ( 25.18 ) 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 On Mon, Mar 25, 2024 at 03:46:01PM -0700, Bo Gan wrote: > On 3/25/24 9:40 AM, Jisheng Zhang wrote: > > Currently, PAGE_OFFSET is hardcoded as 0x8000_0000, it works fine since > > there's only one nommu platform in the mainline. However, there are > > many cases where the (S)DRAM base address isn't 0x8000_0000, so remove > > the hardcoding value, and introduce DRAM_BASE which will be set by > > users during configuring. DRAM_BASE is 0x8000_0000 by default. > > > > Signed-off-by: Jisheng Zhang > > --- > > arch/riscv/Kconfig | 8 +++++++- > > 1 file changed, 7 insertions(+), 1 deletion(-) > > > > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig > > index 7895c77545f1..afd51dbdc253 100644 > > --- a/arch/riscv/Kconfig > > +++ b/arch/riscv/Kconfig > > @@ -247,10 +247,16 @@ config MMU > > Select if you want MMU-based virtualised addressing space > > support by paged memory management. If unsure, say 'Y'. > > +if !MMU > > +config DRAM_BASE > > + hex '(S)DRAM Base Address' > > + default 0x80000000 > > +endif > > + > > config PAGE_OFFSET > > hex > > default 0xC0000000 if 32BIT && MMU > > - default 0x80000000 if !MMU > > + default DRAM_BASE if !MMU > > default 0xff60000000000000 if 64BIT > > config KASAN_SHADOW_OFFSET > > > > Thanks for this patch. I did something similar in my local nommu > linux-6.8 tree in order to run it on the S7 hart of JH7110. I have > another suggestion for you. Perhaps we should also make TASK_SIZE > configurable, and let it default to `0xffffffff if 32BIT && !MMU` > and `DRAM_BASE + DRAM_SIZE if 64BIT && !MMU`. Currently TASK_SIZE > is effectively `0xffffffff if !MMU`, which doesn't work if I run > rv64 linux-nommu with DDR that spans across 4G boundary. I must admit that there's such nommu linux with 4GB DDR case in theory, but it doesn't exist in real world: who will make such strange platform ;) But anyway this improvement can be made when the patchset talking about TASK_SIZE_MAX is settled down. > > I see there's another patchset that tries to define TASK_SIZE_MAX > for __access_ok(). Looks like that only affects the MMU case, and > NOMMU is not touched. My aforementioned change won't conflict with > it should it get merged. > > Bo _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv