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 2B163CD11DD for ; Wed, 27 Mar 2024 01:28:31 +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=gojshyhU1Wj8evhTcJbJ3YCATPRL3oeTuJc7Ora/ZSY=; b=FBYOyym6oemaGQ 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CC606C433F1; Wed, 27 Mar 2024 01:28:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1711502884; bh=tsD1Jo9bLVDB9au4XppIzlJwr4H/IPzxGg62vjK5zl4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=hNDC+7s0VfwR+gTfhz2HUgmUnSqlpSpwat9bUdUF8qcUUcJcuP/ClB89Wd+BYhFF5 ubSJ1zx2I9f+NWaX97dCfLgvWGhM34r4BSqbDqpDHOWs77VVabA1guPHdU9g4LmVfA bup/pfgu2cxyo5sHfx5oJ3ZqUVAxSt8VDzyLObUb+xMSZ9/2KZ/J1myva/cVHEaPEs zBItPMxmpV1Vem1Xlmjljr9AH/SfP1BYVS+FhkqRAf4HVKJcmvJCmd7qbqCPNRoNjP LudduteyX54EwisQZtSjXvxquEmfpeATshe1j2QG+VW+UMlk3HBCoVkjkaaBNrFLct V4teYOp4Rvugw== Date: Wed, 27 Mar 2024 09:14:47 +0800 From: Jisheng Zhang To: Charles Lohr Cc: Palmer Dabbelt , cleger@rivosinc.com, Conor Dooley , samuel.holland@sifive.com, Paul Walmsley , aou@eecs.berkeley.edu, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, Conor Dooley , ajones@ventanamicro.com, dlemoal@kernel.org, Bjorn Topel , Atish Patra Subject: Re: [PATCH] riscv: deprecate CONFIG_MMU=n Message-ID: References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240326_182812_050608_82250C83 X-CRM114-Status: GOOD ( 59.32 ) 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="utf-8" Content-Transfer-Encoding: base64 Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org T24gVHVlLCBNYXIgMjYsIDIwMjQgYXQgMDE6MjU6MDhQTSAtMDcwMCwgQ2hhcmxlcyBMb2hyIHdy b3RlOgo+IEppc2hlbmcsIGFyZSB5b3UgdXNpbmcgbXVzbCBvciB1Y2xpYmM/IEkndmUgYmVlbiBo YXZpbmcgZGlmZmljdWx0eQo+IGdldHRpbmcgbmV3IHZlcnNpb25zIG9mIGVhY2ggd29ya2luZyB3 aXRoIHRoZSBuZXdlciBrZXJuZWxzIHdpdGgKPiBzeXN0ZW0gY2FsbHMgbm90IGxpbmluZyB1cC4K CkhpIENoYXJsZXMsCgpJIHRlc3RlZCBub21tdSBsaW51eCB3aXRoIHVjbGliYywgYm90aCBydjMy 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header.b=hNDC+7s0; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="hNDC+7s0" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CC606C433F1; Wed, 27 Mar 2024 01:28:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1711502884; bh=tsD1Jo9bLVDB9au4XppIzlJwr4H/IPzxGg62vjK5zl4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=hNDC+7s0VfwR+gTfhz2HUgmUnSqlpSpwat9bUdUF8qcUUcJcuP/ClB89Wd+BYhFF5 ubSJ1zx2I9f+NWaX97dCfLgvWGhM34r4BSqbDqpDHOWs77VVabA1guPHdU9g4LmVfA bup/pfgu2cxyo5sHfx5oJ3ZqUVAxSt8VDzyLObUb+xMSZ9/2KZ/J1myva/cVHEaPEs zBItPMxmpV1Vem1Xlmjljr9AH/SfP1BYVS+FhkqRAf4HVKJcmvJCmd7qbqCPNRoNjP LudduteyX54EwisQZtSjXvxquEmfpeATshe1j2QG+VW+UMlk3HBCoVkjkaaBNrFLct V4teYOp4Rvugw== Date: Wed, 27 Mar 2024 09:14:47 +0800 From: Jisheng Zhang To: Charles Lohr Cc: Palmer Dabbelt , cleger@rivosinc.com, Conor Dooley , samuel.holland@sifive.com, Paul Walmsley , aou@eecs.berkeley.edu, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, Conor Dooley , ajones@ventanamicro.com, dlemoal@kernel.org, Bjorn Topel , Atish Patra Subject: Re: [PATCH] riscv: deprecate CONFIG_MMU=n Message-ID: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Tue, Mar 26, 2024 at 01:25:08PM -0700, Charles Lohr wrote: > Jisheng, are you using musl or uclibc? I've been having difficulty > getting new versions of each working with the newer kernels with > system calls not lining up. Hi Charles, I tested nommu linux with uclibc, both rv32 and rv64 Thanks > > Also, is there a better place to ask questions about the more > user-spacy stuff? That's really where I've been struggling to > maintain things, keeping buildroot working when targeting RV32 NOMMU. > Thankfully a lot of the stickiest problems have all been upstreamed. > > Charles > > On Mon, Mar 25, 2024 at 10:12 AM Jisheng Zhang wrote: > > > > On Thu, Mar 14, 2024 at 09:02:43PM +0800, Jisheng Zhang wrote: > > > On Thu, Mar 14, 2024 at 08:46:21PM +0800, Jisheng Zhang wrote: > > > > On Tue, Feb 27, 2024 at 08:38:50AM -0800, Palmer Dabbelt wrote: > > > > > On Tue, 27 Feb 2024 01:11:41 PST (-0800), cleger@rivosinc.com wrote: > > > > > > > > > > > > > > > > > > On 26/02/2024 20:00, Charles Lohr wrote: > > > > > > > WOAH! Please DO NOT deprecate NOMMU. I use the NOMMU build constantly > > > > > > > and NOMMU Linux on RISC-V is the avenue used by many FPGA soft cores > > > > > > > for Linux, as well as some limited systems. > > > > > > > > > > OK. > > > > > > > > > > I just build test this stuff, as I don't really have a use for it > > > > > personally. I figured if nobody's reporting bugs then probably it's broken > > > > > and nobody's noticed because nobody's using it. > > > > > > > > > > > > I get new copies of the kernel when there are releases and test them > > > > > > > frequently to make sure everything is still working as expected. > > > > > > > > > > I'd actually expected it to be broken, but I guess we managed to avoid > > > > > screwing things up ;) > > > > > > > > > > > > For us we just don't care about XIP. I mean if someone did push it > > > > > > > > I don't care XIP either, and IMHO the XIP's maintenance effort is much > > > > bigger than NOMMU(just check the various XIP_FIXUP* or CONFIG_XIP_KERNEL > > > > macros around lowlevel pgtable.h, page.h). If we can remove XIP, the > > > > code readability will be much better. > > > > > > > > Or sending out a similar XIP deprecation patch to see whether there's > > > > any complain ? ;) > > > > > > > > > > > through to fruition, I'd also test and use it, but I urge you please > > > > > > > do not deprecate this. While it's sometimes needed a bit of a > > > > > > > > +1 for urge the upstream please do not deprecate NOMMU. > > > > > > > > Besides the soft(FPGA) core mentioned by Charles, here is another real > > > > > > And I'd like to write more about soft core: riscv is a free and open > > > ISA, this make it really good for education, for simple riscv > > > implementation or emulator. Once riscv IMA is implemented(even if MMU, > > > cache, TLB stuff don't exist), it's not far away from making linux > > > running on the FPGA or emulator. If the gain is larger than the maintenance > > > effort, I'd like to urge keeping the NOMMU support. > > > > > > Thanks a lot > > > > > > > usage case: As is known, Sophgo CV1800B platforms such as Milk Duo > > > > contains two C906 core, one(a.k.a big core) with MMU another(a.k.a small > > > > core)w/o MMU. The vendor sdk runs freertos on the small core, but it > > > > doesn't prevent users to run other OS such as threadx, zephyr or nommu > > > > linux on the small core. In fact, I sucessfully brought up nommu linux > > > > on the small core. I didn't just send out the patches in time during this > > > > dev window duo to my personal career reason(I spent the time on hunting > > > > for a new job) > > > > > > > > I plan to send out NOMMU related patches once 6.9-rc1 is out. > > > > As is promised, the NOMMU improvement patches are sent out > > https://lore.kernel.org/linux-riscv/20240325164021.3229-1-jszhang@kernel.org/T/#t > > > > Thanks > > > > > > > > > > > > > creative build to get everything working, I've never needed to patch > > > > > > > anything in the kernel beyond patching in a custom console for serial > > > > > > > output. > > > > > > > > > > > > > > > > > > > Hey Charles, > > > > > > > > > > > > No worries, we actually did not expected NOMMU to have *so many* users. > > > > > > I guess deprecating stuff is a good way to have immediate feedback ;). > > > > > > Having FDPIC psABI to be merged upstream could also probably be a > > > > > > positive point toward a better NOMMU support. > > > > > > > > > > Ya, that's probably the right way to do it. Touching anything in the psABI > > > > > is pretty miserable, though, so I don't really want to force people to do > > > > > it... > > > > > > > > > > > > I am happy to discuss the possibility of me and or one of the other > > > > > > > RISC-V soft (FPGA) core people stepping up to try to be more active, > > > > > > > but so far we've just been very well serviced by the current NOMMU > > > > > > > Linux setup. > > > > > > > > > > > > It could probably be nice to have some feedback/Tested-by: from NOMMU > > > > > > users for new releases then. > > > > > > > > > > Having more upstream interaction from users is always appreciated, that's > > > > > the best way to prove people are using the code. If you guys have the time > > > > > it'd be great to get this into some sort of CI, ideally running on some real > > > > > platform. > > > > > > > > As above, I'd also like to step up on the NOMMU stuff, at least test > > > > nommu on milkv duo's small core. And can be seen from my git commit > > > > histotry, I was active, and I belive I will still be active on riscv linux > > > > kernel development. > > > > > > > > > > > > > > > Thanks, > > > > > > > > > > > > Clément > > > > > > > > > > > > > > > > > > > > Charles > > > > > > > > > > > > > > > > > > > > > On Mon, Feb 26, 2024 at 8:03 AM Conor Dooley wrote: > > > > > > > > > > > > > > > > On Mon, Feb 26, 2024 at 04:25:24PM +0100, Clément Léger wrote: > > > > > > > > > I guess I could also mark XIP as deprecated. > > > > > > > > > > > > > > > > I'm not so sure, people recently added XIP support to QEMU (and sent > > > > > > > > kernel fixes in December). XIP is also not nearly as much of a problem > > > > > > > > to support, there's far less that it does differently, the main barrier > > > > > > > > was the inability to test it which is no longer the case. > > > > > > > > That said, XIP is gonna kill itself off I feel as it does not support > > > > > > > > runtime patching and therefore is extremely limited on extensions, given > > > > > > > > we use alternatives for all of that (although I suppose if someone has a > > > > > > > > usecase they could make nasty macros worse and implement a compiletime > > > > > > > > switch in the alternatives too). > > > > > > > > > > > > > > > > Cheers, > > > > > > > > Conor. > > > > > > > > > > > > > > > > _______________________________________________ > > > > > > > > linux-riscv mailing list > > > > > > > > linux-riscv@lists.infradead.org > > > > > > > > http://lists.infradead.org/mailman/listinfo/linux-riscv > > > > > > > > > > _______________________________________________ > > > > > linux-riscv mailing list > > > > > linux-riscv@lists.infradead.org > > > > > http://lists.infradead.org/mailman/listinfo/linux-riscv