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 51E03CA5FC4 for ; Fri, 2 Oct 2026 11:53:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=JmxZmAkX7sFWhZEhSwoTFCk9Ly0sqzCLy0ifziPCklE=; b=H77Rm5RtZSGPq5FfFwEWDBVWfZ AimqHg5gahEb54jZDYxVEnbObXWNGldmM+Rrfdccv6HxtIRNbIWrj7zzDzISEhZ0rb90TRD47WMLp 5Lyp8k+0Owp76gwPBKoMtvl09v17TxJM+AdzIdvnZ3DwljuJ19kzGN3KoaHd451LYzqBJDSAZ08zp fsSaq73bZg2Ze/IUp9OZX5cB5M+Y80vuFnjCjFo8ylLsAViXGnQeGoWENJ61YzYTu5IIfRztF8d5z v/uwbFQgC9lxK98ZN7GmLQDMK3JxUBQqtCrRjJLfHnHbxi77Hi/v8iIFiQIn6fP/1KkAJheJA0ihD oTMeIL+w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1xCbpc-0000000BWIm-0BD1; Fri, 02 Oct 2026 11:53:40 +0000 Received: from sea.source.kernel.org ([2600:3c0a:e001:78e:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1xCbpb-0000000BWIf-1hU0 for linux-um@lists.infradead.org; Fri, 02 Oct 2026 11:53:39 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 1BD5240093; Fri, 2 Oct 2026 11:53:39 +0000 (UTC) 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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-BeenThere: linux-um@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-um" Errors-To: linux-um-bounces+linux-um=archiver.kernel.org@lists.infradead.org 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