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 X-Spam-Level: X-Spam-Status: No, score=-7.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A0943C433ED for ; Fri, 9 Apr 2021 14:17:01 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 48F7D60FF1 for ; Fri, 9 Apr 2021 14:17:01 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 48F7D60FF1 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id D14736B006C; Fri, 9 Apr 2021 10:17:00 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id CEC1F6B006E; Fri, 9 Apr 2021 10:17:00 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id BB3E66B0070; Fri, 9 Apr 2021 10:17:00 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0131.hostedemail.com [216.40.44.131]) by kanga.kvack.org (Postfix) with ESMTP id A2EA06B006C for ; Fri, 9 Apr 2021 10:17:00 -0400 (EDT) Received: from smtpin32.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 5AD07184B0065 for ; Fri, 9 Apr 2021 14:17:00 +0000 (UTC) X-FDA: 78013030200.32.68A0586 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [63.128.21.124]) by imf17.hostedemail.com (Postfix) with ESMTP id 067BA40002D9 for ; Fri, 9 Apr 2021 14:16:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1617977819; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=7lJbgd2hYY827G0NWvg1oy4yBkmSJegYFDEkQ7hgRxA=; b=h9e/ZEl72YLGUXj77m1IkVw2xAwUyM+ZrpFcqLBz6XA9VWGPXC4XCGyYFDRtEjL25GQwHl Dl50wn0KegaICwJt5+Cb8pY4tcsx95oELEJth/AMQVUqZWjNAVY0E2t4zuZYGl2eG5bUNN mbpMwtSk+fM2ipE1lIEMgv9CSIqwNDI= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-554-CbpfF08qOAm3ydVeGePGJg-1; Fri, 09 Apr 2021 10:16:55 -0400 X-MC-Unique: CbpfF08qOAm3ydVeGePGJg-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 39E0B807344; Fri, 9 Apr 2021 14:16:54 +0000 (UTC) Received: from [10.36.115.11] (ovpn-115-11.ams2.redhat.com [10.36.115.11]) by smtp.corp.redhat.com (Postfix) with ESMTP id 6FF2A648A1; Fri, 9 Apr 2021 14:16:51 +0000 (UTC) Subject: Re: [PATCH v7] RISC-V: enable XIP To: Mike Rapoport Cc: Alex Ghiti , Paul Walmsley , Palmer Dabbelt , Albert Ou , linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, Vitaly Wool References: <20210409065115.11054-1-alex@ghiti.fr> <3500f3cb-b660-5bbc-ae8d-0c9770e4a573@ghiti.fr> From: David Hildenbrand Organization: Red Hat GmbH Message-ID: <2d442bca-c367-598c-b4ee-746925517118@redhat.com> Date: Fri, 9 Apr 2021 16:16:50 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Rspamd-Queue-Id: 067BA40002D9 X-Stat-Signature: 58o6njnxgptb1r58wfbses1rb9154z7k X-Rspamd-Server: rspam02 Received-SPF: none (redhat.com>: No applicable sender policy available) receiver=imf17; identity=mailfrom; envelope-from=""; helo=us-smtp-delivery-124.mimecast.com; client-ip=63.128.21.124 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1617977817-472455 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 09.04.21 16:10, Mike Rapoport wrote: > On Fri, Apr 09, 2021 at 02:07:24PM +0200, David Hildenbrand wrote: >> On 09.04.21 13:39, Alex Ghiti wrote: >>> Hi David, >> >> I assume you still somehow create the direct mapping for the kernel, right? >> So it's really some memory region with a direct mapping but without a memmap >> (and right now, without a resource), correct? > > XIP kernel text is not a region in memory to begin with ;-) I think that's the part that confused me. I thought it would be mapped somehow into physical address space and would be addressed like other memory -- just that reads would be rewired to go to flash. > > It resides in a flash and it is executed directly from there without being > relocated to RAM. > > That's why it does not need neither direct mapping, nor struct pages. Thanks for clarifying! :) -- Thanks, David / dhildenb