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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id CE746C433FE for ; Tue, 24 May 2022 01:12:07 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 4B5E56B0072; Mon, 23 May 2022 21:12:07 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 464C66B0073; Mon, 23 May 2022 21:12:07 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 352FE6B0074; Mon, 23 May 2022 21:12:07 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 25B606B0072 for ; Mon, 23 May 2022 21:12:07 -0400 (EDT) Received: from smtpin04.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay12.hostedemail.com (Postfix) with ESMTP id DDC421211BB for ; Tue, 24 May 2022 01:12:06 +0000 (UTC) X-FDA: 79498860252.04.8118FA3 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by imf07.hostedemail.com (Postfix) with ESMTP id C981740034 for ; Tue, 24 May 2022 01:11:55 +0000 (UTC) Received: from dggpemm500021.china.huawei.com (unknown [172.30.72.54]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4L6bgf2Ms7zQkHB; Tue, 24 May 2022 09:09:02 +0800 (CST) Received: from dggpemm500014.china.huawei.com (7.185.36.153) by dggpemm500021.china.huawei.com (7.185.36.109) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Tue, 24 May 2022 09:12:01 +0800 Received: from [10.174.178.120] (10.174.178.120) by dggpemm500014.china.huawei.com (7.185.36.153) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Tue, 24 May 2022 09:12:00 +0800 Message-ID: <262cab19-0bca-a088-77a5-6a41f475f4a4@huawei.com> Date: Tue, 24 May 2022 09:11:59 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.8.0 Subject: Re: [PATCH 0/2] Add support to relocate kernel image to mirrored region To: CC: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , References: <20220419070150.254377-1-mawupeng1@huawei.com> <7058b8d8-c0cb-108e-0db9-2fdf5fb154cf@huawei.com> <7a1ce182-343a-75f9-5447-f7ca12cb0c36@huawei.com> From: mawupeng In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.174.178.120] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To dggpemm500014.china.huawei.com (7.185.36.153) X-CFilter-Loop: Reflected X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: C981740034 X-Stat-Signature: goztuc3gr8pez9b1ddaa7xk8u3pzpssy X-Rspam-User: Authentication-Results: imf07.hostedemail.com; dkim=none; spf=pass (imf07.hostedemail.com: domain of mawupeng1@huawei.com designates 45.249.212.188 as permitted sender) smtp.mailfrom=mawupeng1@huawei.com; dmarc=pass (policy=quarantine) header.from=huawei.com X-HE-Tag: 1653354715-71487 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: 在 2022/5/23 22:41, Ard Biesheuvel 写道: > On Mon, 23 May 2022 at 03:18, mawupeng wrote: >> >> >> >> 在 2022/5/20 14:52, Ard Biesheuvel 写道: >>> On Thu, 19 May 2022 at 13:09, mawupeng wrote: >>>> >>>> >>>> >>>> 在 2022/5/7 17:28, mawupeng 写道: >>>>> >>>>> >>>>> 在 2022/5/3 17:58, Ard Biesheuvel 写道: >>>>>> On Tue, 19 Apr 2022 at 08:43, Wupeng Ma wrote: >>>>>>> >>>>>>> From: Ma Wupeng >>>>>>> >>>>>>> Now system image will perfer to be located to mirrored regions both KASLR >>>>>>> on and off. >>>>>>> >>>>>> >>>>>> Hello Ma Wupeng, >>>>>> >>>>>> I wonder if we could simplify this as follows: >>>>>> - ignore the non-KASLR case for now, and rely on the bootloader > load the image into mirrored memory if it exists; >>>>> >>>>> In grub, memory for static image is allocated via the following path: >>>>> >>>>> grub_cmd_linux >>>>> kernel = grub_malloc(filelen) >>>>> kernel_alloc_addr = grub_efi_allocate_any_pages (kernel_alloc_pages) >>>>> grub_memcpy (kernel_addr, kernel, grub_min(filelen, kernel_size)) >>>>> grub_loader_set (grub_linux_boot, grub_linux_unload, 0) >>>>> >>>>> Can we get memory from mirrored region by the following steps: >>>>> 1. get memory map by calling grub_efi_get_memory_map() >>>>> 2. iter all memory map to find a suitable mirrored memory area >>>>> 3. locate kernel image to this area >>>>> >>>>> So, if kaslr is not enabled >>>>> - grub will load kernel into mirrored region >>>>> else >>>>> - arm64-stub.c will relocate kernel image to mirrored region >>>>> >>>>> Is this feasible? >>>> >>>> Is this a feasible proposal to relocate the static kernel image itself >>>> into more reliable memory? >>>> >>> >>> I'm not sure, it all depends on the firmware. >>> >>> When GRUB calls LoadImage(), the firmware will reallocate the image >>> and unpack it there. So it is really the firmware's job to ensure that >>> the image is loaded into a suitable location. >>> >>> I have some code here that implements a EFI based decompressor, and >>> which loads the kernel image into mirrored memory if it exists, >>> without the need to move it again. It could trivially be modified to >>> deal with non-randomized loads as well. >>> >>> But the bottom line is that UEFI should expose the ability to target >>> mirrored memory, hacking around it like this is not a sustainable >>> approach. >> >> Since firmware is responsible for put kernel static image into mirrored >> region and kernel is responsible for relocate this image into mirrored >> region if kaslr is enabled. There is no conflict between these two. >> >> Can we integrate the kernel part(introduce mirrored support to arm64) first? >> > > Yes. If you drop the changes related to fake memmap and rebase, please > resend them after -rc1 is released. Ok, I will drop the changes related to fake memmap and rebase and then resend them after -rc1 is released. Thanks for reviewing. > .