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,URIBL_BLOCKED,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 DBD8FC433DB for ; Fri, 12 Feb 2021 18:29:15 +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 6281A64DEA for ; Fri, 12 Feb 2021 18:29:15 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6281A64DEA 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=CmhSUv5FCJVjJqlecZXkEv6e/F/GKVTRCu2wdtl4tII=; b=o2/kFaCjJeFZdiY5F2dzsk1vx +MRjUqxlPFJQcUv1oAGoV2HU66XkKbC4lgR0aTxpdd6uTB37VWKgQnvrATSBlFn/lCTOv2AZDWOHA G9P4JgURQ98h3166dFLrzznAKoeMH9yiu+5WPstq9nEjt7+MX6ZNp7S+SdND+5dBOcKlTbUBij7Gk JNYBWon/F3/wALAXfoTUNdG5PRuN6PylYdAPgfVQQrAvMxAVbf7gSemqDuDFmxsdo6xATK0ZWWrI5 vLPnCZVM+7nXf6YBsetny83nzqr4YAk65/byLlsN9JecMXmQCp8lcAhr4q4VN5V+Irv5C5rpQw1fO qzwFTdpJg==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1lAdAg-0007WG-PO; Fri, 12 Feb 2021 18:28:02 +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 1lAdAc-0007V8-Qf for linux-arm-kernel@lists.infradead.org; Fri, 12 Feb 2021 18:27:59 +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 CA96E20B6C40; Fri, 12 Feb 2021 10:27:56 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com CA96E20B6C40 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1613154477; bh=cflwvEQVmR2Liv6dfdrVeSAaocg0bLd1F49bz3eKPjU=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=clVeMuPjnkrNi1QWeejXFkDLfR59r4IhU4i4C1FxfsXzaIyYqoURk4pXCM1pEHuWh iO+L3UR8oGXcIZtNqVSL65uV8wh+RgArEbCqaAynyzLx/5Qh/rzaUmBxRGyogYQ9RP kkSU7JBuQzni0CLZHSBomQflDz5KmNF4TMYftQUo= 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> <55685b61-dac0-2f24-f74a-939acf74a4f2@linux.microsoft.com> From: Lakshmi Ramasubramanian Message-ID: <11aff288-feaa-8e43-fcda-12bc12fbf4cf@linux.microsoft.com> Date: Fri, 12 Feb 2021 10:27:56 -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_132759_071916_90300848 X-CRM114-Status: GOOD ( 21.99 ) 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 10:24 AM, Rob Herring wrote: > On Fri, Feb 12, 2021 at 11:19 AM Lakshmi Ramasubramanian > wrote: >> >> 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. > > Yes, I'd leave the 4KB in there by default and arm64 use 0. > Sounds good. common: fdt_totalsize(initial_boot_params) + strlen(cmdline) + 0x1000 + extra arm64 => 0 for extra ppc => fdt_totalsize(initial_boot_params) for extra. -lakshmi _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel