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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham 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 0A535C6778C for ; Tue, 3 Jul 2018 16:32:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BC63824728 for ; Tue, 3 Jul 2018 16:32:24 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BC63824728 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933912AbeGCQcU (ORCPT ); Tue, 3 Jul 2018 12:32:20 -0400 Received: from foss.arm.com ([217.140.101.70]:52310 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932392AbeGCQcQ (ORCPT ); Tue, 3 Jul 2018 12:32:16 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 0F2E97A9; Tue, 3 Jul 2018 09:32:16 -0700 (PDT) Received: from [10.1.206.34] (melchizedek.cambridge.arm.com [10.1.206.34]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 0C6CD3F5BA; Tue, 3 Jul 2018 09:32:11 -0700 (PDT) Subject: Re: [PATCH v10 08/14] arm64: kexec_file: load initrd and device-tree To: AKASHI Takahiro , catalin.marinas@arm.com, will.deacon@arm.com, dhowells@redhat.com, vgoyal@redhat.com, herbert@gondor.apana.org.au, davem@davemloft.net, dyoung@redhat.com, bhe@redhat.com, arnd@arndb.de Cc: ard.biesheuvel@linaro.org, bhsharma@redhat.com, kexec@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <20180623022058.10935-1-takahiro.akashi@linaro.org> <20180623022058.10935-9-takahiro.akashi@linaro.org> From: James Morse Message-ID: <1e401f4e-6176-990d-476c-31ae3f28f26c@arm.com> Date: Tue, 3 Jul 2018 17:32:09 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 MIME-Version: 1.0 In-Reply-To: <20180623022058.10935-9-takahiro.akashi@linaro.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Akashi, On 23/06/18 03:20, AKASHI Takahiro wrote: > load_other_segments() is expected to allocate and place all the necessary > memory segments other than kernel, including initrd and device-tree > blob (and elf core header for crash). > While most of the code was borrowed from kexec-tools' counterpart, > users may not be allowed to specify dtb explicitly, instead, the dtb > presented by the original boot loader is reused. > > arch_kimage_kernel_post_load_cleanup() is responsible for freeing arm64- > specific data allocated in load_other_segments(). > diff --git a/arch/arm64/kernel/machine_kexec_file.c b/arch/arm64/kernel/machine_kexec_file.c > index c38a8048ed00..7115c4f915dc 100644 > --- a/arch/arm64/kernel/machine_kexec_file.c > +++ b/arch/arm64/kernel/machine_kexec_file.c > +static int setup_dtb(struct kimage *image, > + unsigned long initrd_load_addr, unsigned long initrd_len, > + char *cmdline, unsigned long cmdline_len, > + char **dtb_buf, size_t *dtb_buf_len) > +{ > + char *buf = NULL; > + size_t buf_size; > + int nodeoffset; > + u64 value; > + int ret; > + > + /* duplicate dt blob */ > + buf_size = fdt_totalsize(initial_boot_params); > + > + if (initrd_load_addr) { > + buf_size += fdt_prop_len("linux,initrd-start", sizeof(u64)); > + buf_size += fdt_prop_len("linux,initrd-end", sizeof(u64)); > + } > + > + if (cmdline) > + buf_size += fdt_prop_len("bootargs", cmdline_len + 1); (a comment here about the possibility of an embedded NULL may avoid surprises later) > + buf = vmalloc(buf_size); > + if (!buf) { > + ret = -ENOMEM; > + goto out_err; > + } > + > + ret = fdt_open_into(initial_boot_params, buf, buf_size); > + if (ret) > + goto out_err; > + > + nodeoffset = fdt_path_offset(buf, "/chosen"); > + if (nodeoffset < 0) > + goto out_err; This doesn't update 'ret', so we return the 0/success from above... > + > + /* add bootargs */ > + if (cmdline) { > + ret = fdt_setprop(buf, nodeoffset, "bootargs", > + cmdline, cmdline_len + 1); > + if (ret) > + goto out_err; > + } So (cmdline_len == 0) from user-space means keep the old cmdline. Sounds sensible. Is this documented anywhere? powerpc does the opposite, it deletes the bootargs in this case. Are we happy making his a per-arch thing? > + /* add initrd-* */ > + if (initrd_load_addr) { > + value = cpu_to_fdt64(initrd_load_addr); > + ret = fdt_setprop_u64(buf, nodeoffset, "linux,initrd-start", > + value); > + if (ret) > + goto out_err; > + > + value = cpu_to_fdt64(initrd_load_addr + initrd_len); > + ret = fdt_setprop_u64(buf, nodeoffset, "linux,initrd-end", > + value); > + if (ret) > + goto out_err; > + } Won't this do the same with the initrd? Re-use the old values if no new one was provided? I can't find anything that deletes the property by the time we come to kexec, and the old physical addresses may have been re-used by who-knows-what. (powerpc has some code to: /* If there's no new initrd, delete the old initrd's info. */) Thanks, James