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=-5.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,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 9A331C433DB for ; Fri, 12 Feb 2021 17:20:17 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 6121F64E02 for ; Fri, 12 Feb 2021 17:20:17 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6121F64E02 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.microsoft.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Type: Content-Transfer-Encoding:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=4ZX6YTqhgFftdulspS7mcL2BmECo/bh9/CY+hUC+chg=; b=mkz6PL0m3NSpP+juPrrQQe8m1 tlkdTzfzupBYFIQsa71oRipXC10wMJJiQGVeG/iXSIvw3AruWnRhabHsrRtK+dpQQzLZKggCxFU9i t45dVlULwMdkWqE4I2a5u4vbDMslV3b7OIhkPrzB4V3w7msOVA017cXnJEPp02Km5I1Ww2yLJmIhY 7LNmOa1hhDxAQ/Foh0F84bwu/3JZAVFvt5GGM52v9bMaM29eG06VQ7r8W1VrhKwe5mAG4gqH2DKkI AcMwQIdQrmTrKCn0Zy2NYk9YU3cfHy0O8vzsNJ4QecQhKetN9xun5dUcWLc8T2vSFyjxKUvgLYO8q Sq0om+81w==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1lAc5z-0007CP-66; Fri, 12 Feb 2021 17:19:07 +0000 Received: from linux.microsoft.com ([13.77.154.182]) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1lAc5w-0007Br-8S for linux-arm-kernel@lists.infradead.org; Fri, 12 Feb 2021 17:19:05 +0000 Received: from [192.168.0.104] (c-73-42-176-67.hsd1.wa.comcast.net [73.42.176.67]) by linux.microsoft.com (Postfix) with ESMTPSA id C5C7020B6C40; Fri, 12 Feb 2021 09:19:00 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com C5C7020B6C40 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1613150341; bh=ymZC2uSu1WhDmmhzMMk+j693znWvxWsQ0oRGutDXsUU=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=UFctr/CjGfWUVNUkmlcZdiSnRimSYXYpf7boiSafTdIohyW4op8aqXiOPIXG7tD9w 2+CCCjIQwjmCzRCgCyJOtrEfXaan1toeQ6tewZfvQeoz8k1bHJnQ/MjJqkkzxmgjf+ fBeDNBT4ANHJIZyDIIuAoR7Wx92T/5Rbhxu+1Yog= Subject: Re: [PATCH v17 02/10] of: Add a common kexec FDT setup function To: Rob Herring References: <20210209182200.30606-1-nramas@linux.microsoft.com> <20210209182200.30606-3-nramas@linux.microsoft.com> <87k0reozwh.fsf@manicouagan.localdomain> <8a3aa3d2-2eba-549a-9970-a2b0fe3586c9@linux.microsoft.com> From: Lakshmi Ramasubramanian Message-ID: <55685b61-dac0-2f24-f74a-939acf74a4f2@linux.microsoft.com> Date: Fri, 12 Feb 2021 09:19:00 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210212_121904_448126_0B5F411B X-CRM114-Status: GOOD ( 23.69 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Benjamin Herrenschmidt , tao.li@vivo.com, Mimi Zohar , Paul Mackerras , vincenzo.frascino@arm.com, Frank Rowand , Sasha Levin , Michael Ellerman , Masahiro Yamada , James Morris , "AKASHI, Takahiro" , linux-arm-kernel , Catalin Marinas , "Serge E. Hallyn" , devicetree@vger.kernel.org, Pavel Tatashin , Will Deacon , Prakhar Srivastava , Hsin-Yi Wang , Allison Randal , Christophe Leroy , Matthias Brugger , balajib@linux.microsoft.com, dmitry.kasatkin@gmail.com, "linux-kernel@vger.kernel.org" , James Morse , Greg Kroah-Hartman , Joe Perches , linux-integrity@vger.kernel.org, linuxppc-dev , Thiago Jung Bauermann Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 2/12/21 6:38 AM, Rob Herring wrote: > On Thu, Feb 11, 2021 at 7:17 PM Lakshmi Ramasubramanian > wrote: >> >> On 2/11/21 5:09 PM, Thiago Jung Bauermann wrote: >>> >>> There's actually a complication that I just noticed and needs to be >>> addressed. More below. >>> >> >> <...> >> >>>> + >>>> +/* >>>> + * of_kexec_alloc_and_setup_fdt - Alloc and setup a new Flattened Device Tree >>>> + * >>>> + * @image: kexec image being loaded. >>>> + * @initrd_load_addr: Address where the next initrd will be loaded. >>>> + * @initrd_len: Size of the next initrd, or 0 if there will be none. >>>> + * @cmdline: Command line for the next kernel, or NULL if there will >>>> + * be none. >>>> + * >>>> + * Return: fdt on success, or NULL errno on error. >>>> + */ >>>> +void *of_kexec_alloc_and_setup_fdt(const struct kimage *image, >>>> + unsigned long initrd_load_addr, >>>> + unsigned long initrd_len, >>>> + const char *cmdline) >>>> +{ >>>> + void *fdt; >>>> + int ret, chosen_node; >>>> + const void *prop; >>>> + unsigned long fdt_size; >>>> + >>>> + fdt_size = fdt_totalsize(initial_boot_params) + >>>> + (cmdline ? strlen(cmdline) : 0) + >>>> + FDT_EXTRA_SPACE; >>> >>> Just adding 4 KB to initial_boot_params won't be enough for crash >>> kernels on ppc64. The current powerpc code doubles the size of >>> initial_boot_params (which is normally larger than 4 KB) and even that >>> isn't enough. A patch was added to powerpc/next today which uses a more >>> precise (but arch-specific) formula: >>> >>> https://lore.kernel.org/linuxppc-dev/161243826811.119001.14083048209224609814.stgit@hbathini/ >>> >>> So I believe we need a hook here where architectures can provide their >>> own specific calculation for the size of the fdt. Perhaps a weakly >>> defined function providing a default implementation which an >>> arch-specific file can override (a la arch_kexec_kernel_image_load())? >>> >>> Then the powerpc specific hook would be the kexec_fdt_totalsize_ppc64() >>> function from the patch I linked above. >>> >> >> Do you think it'd better to add "fdt_size" parameter to >> of_kexec_alloc_and_setup_fdt() so that the caller can provide the >> desired FDT buffer size? > > Yes, I guess so. But please define the param as extra size, not total > size. The kernel command line size addition can be in the common code. Will do. Just to clarify - The common code will do: fdt_totalsize(initial_boot_params) + strlen(cmdline) + extra_fdt_size The caller will pass "extra_fdt_size" ARM64 => 4KB PPC64 => fdt_totalsize(initial_boot_params) - which will be updated when the patch Thiago had referred to is merged. > > The above change is also going to conflict, so I think this may have > to wait. Or I'll take the common and arm bits and powerpc can be > converted next cycle (or after the merge window). > thanks. -lakshmi _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel