From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7C84337A498; Fri, 2 Oct 2026 11:53:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790942020; cv=none; b=GZ7nLJXsdjN2mFnCtP1YyyZyxuMiX3zbjdVhzME50QiptGEjzvl2Sc6GrLLEFb84pVlKV8hvZAZGYdGqruoE376J3CTDieDVbm0Flw6ibGYvjdMsVvsQ/Z9KeEhZ+zsSMGmuXnGMsoD/eyY7/TXsLJe+R0X/w7NPyfsUbVIXxzA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790942020; c=relaxed/simple; bh=JmxZmAkX7sFWhZEhSwoTFCk9Ly0sqzCLy0ifziPCklE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=IRps4JLgymQAGiKKNQTSo3CuAJ4QeVhWZFkrrg67Bmrpz9CdMt8vpvYKauJIhm2YoVYXMWIg8zS6bH9biSiim58DvZJPiFiluIhLOkdOSAZ5B4/+zVNb1twK6prgKPu5nd92nB2TGjiG1OmquCTiRimWCUF4cYOdA8NwP8H8JRg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=LrjaOiT0; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="LrjaOiT0" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C51911F000FF; Fri, 2 Oct 2026 11:53:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790942019; bh=JmxZmAkX7sFWhZEhSwoTFCk9Ly0sqzCLy0ifziPCklE=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=LrjaOiT0/kgKG5xJcHuIQQl96aDNH27jEWYo6/eukxIaqQwYL0Yi2fb+zu/vFRBId DV/PZj2ePkgKFhE9/F4nvTYUADBF7H7T9RJOwDn3NIgMGlyMKcDuTAtoTIIkUsgDb6 x1URYwePs3Vebu4nOuyyzGzHW5Vn2MCe8aXxTi+YGMS6b0csgZWtq74p7c08jB9xPQ ZpKgg9fwiync7utyBiMm2bPjVpvUOrU7S6mG7pstrUJvNj/jPcuRO+yDhhTGtADvXL 1IZ7ntsJFFvW9x/WXyQUNm7oAqTFgJ+zZzw2Hn0ou+zpclpaPwQJ68poxNuVNU2M6q o+8PkQiPxtQUA== Date: Fri, 2 Oct 2026 12:53:31 +0100 From: "Lorenzo Stoakes (ARM)" To: Geert Uytterhoeven Cc: "David Hildenbrand (Arm)" , Hajime Tazaki , johannes@sipsolutions.net, linux-mm@kvack.org, liam@infradead.org, rbm@suse.com, akpm@linux-foundation.org, luto@amacapital.net, brendan.jackman@linux.dev, liuhangbin@gmail.com, corbet@lwn.net, kees@kernel.org, broonie@kernel.org, mhocko@suse.com, rppt@kernel.org, shuah@kernel.org, surenb@google.com, vbabka@kernel.org, wad@chromium.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-um@lists.infradead.org, daniel@thingy.jp Subject: Re: [PATCH v4 1/2] selftests: run tests on nommu architecture Message-ID: References: <20260929235711.2287931-1-thehajime@gmail.com> <20260929235711.2287931-2-thehajime@gmail.com> <94759bed23f00d2044005e36be6f72f297e092f0.camel@sipsolutions.net> Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Fri, Oct 02, 2026 at 01:38:31PM +0200, Geert Uytterhoeven wrote: > On Fri, 2 Oct 2026 at 10:10, Lorenzo Stoakes (ARM) wrote: > > But fork() -> -EINVAL or -ENOSYS = nommu, then just have the child quit and > > etc. should do it. > > fork() is not strictly an MMU-feature (you can implement fork on nommu > if all memory accesses are done relative to a base address register), > while I think mprotect() is an MMU-feature. Unless it can also be used > to change the protection using the one or two BARs most MCU haves? > Anything else that is a real MMU-feature? Non-identity mmap()? Does any nommu arch implement fork() in linux? -- Cheers, Lorenzo