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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A0C05C433FE for ; Wed, 29 Sep 2021 12:13:46 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 4457F61406 for ; Wed, 29 Sep 2021 12:13:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 4457F61406 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id AF19994001F; Wed, 29 Sep 2021 08:13:45 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id AA0916B0093; Wed, 29 Sep 2021 08:13:45 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9686494001F; Wed, 29 Sep 2021 08:13:45 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0162.hostedemail.com [216.40.44.162]) by kanga.kvack.org (Postfix) with ESMTP id 82B8C6B0092 for ; Wed, 29 Sep 2021 08:13:45 -0400 (EDT) Received: from smtpin03.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 3C4A629DEF for ; Wed, 29 Sep 2021 12:13:45 +0000 (UTC) X-FDA: 78640502010.03.AC9DE66 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf06.hostedemail.com (Postfix) with ESMTP id DA9C9801AB04 for ; Wed, 29 Sep 2021 12:13:44 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id 912516138E; Wed, 29 Sep 2021 12:13:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1632917624; bh=Xbtbg+mivL4Gh8sTI2cm/XRW1HEdKhYPFMoHfjA9G28=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=IVThRYjz74LKPeRkGCHK1GgyAxTVXkLxGJgnGB08o3ctLNMMcschwUpw1sWl+YHKT H4F3IFXpr00Cdbu6HCXQwu/ZoybEKYaxtEvxnqCpGcZ0CqrPBKkKf9Ova9X8glwfWw 4Nx2pUOCb/5qx/sD84U+A0P24heAwBY1igJw44dymW2nNLculvmHA0orXV0FUdXCUc yCFeRr4X6U6+HjfRnNhXaoLCquYRUlJRUcud9yqb8wzN/Z3NkPdbA5vR9fV5z9rfKJ 04aA6vjRur+13bBY41DXUIzJMVu/m7863H4N/1sT6AekB2JwxL9gPnTk/xgbkEy6GM K2NcYURfh0XfQ== Date: Wed, 29 Sep 2021 13:13:37 +0100 From: Will Deacon To: Pasha Tatashin Cc: jmorris@namei.org, sashal@kernel.org, ebiederm@xmission.com, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, corbet@lwn.net, catalin.marinas@arm.com, linux-arm-kernel@lists.infradead.org, maz@kernel.org, james.morse@arm.com, vladimir.murzin@arm.com, matthias.bgg@gmail.com, linux-mm@kvack.org, mark.rutland@arm.com, steve.capper@arm.com, rfontana@redhat.com, tglx@linutronix.de, selindag@gmail.com, tyhicks@linux.microsoft.com, kernelfans@gmail.com, akpm@linux-foundation.org, madvenka@linux.microsoft.com Subject: Re: [PATCH v17 05/15] arm64: kexec: skip relocation code for inplace kexec Message-ID: <20210929121336.GB21631@willie-the-truck> References: <20210916231325.125533-1-pasha.tatashin@soleen.com> <20210916231325.125533-6-pasha.tatashin@soleen.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210916231325.125533-6-pasha.tatashin@soleen.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: DA9C9801AB04 X-Stat-Signature: o6pytzipnmfb4mhhomd1kqiztjn34oby Authentication-Results: imf06.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=IVThRYjz; dmarc=pass (policy=none) header.from=kernel.org; spf=pass (imf06.hostedemail.com: domain of will@kernel.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=will@kernel.org X-HE-Tag: 1632917624-382155 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 Thu, Sep 16, 2021 at 07:13:15PM -0400, Pasha Tatashin wrote: > In case of kdump or when segments are already in place the relocation > is not needed, therefore the setup of relocation function and call to > it can be skipped. > > Signed-off-by: Pasha Tatashin > Suggested-by: James Morse > --- > arch/arm64/kernel/machine_kexec.c | 34 ++++++++++++++++++----------- > arch/arm64/kernel/relocate_kernel.S | 3 --- > 2 files changed, 21 insertions(+), 16 deletions(-) [...] > @@ -188,19 +190,25 @@ void machine_kexec(struct kimage *kimage) > local_daif_mask(); > > /* > - * cpu_soft_restart will shutdown the MMU, disable data caches, then > - * transfer control to the kern_reloc which contains a copy of > - * the arm64_relocate_new_kernel routine. arm64_relocate_new_kernel > - * uses physical addressing to relocate the new image to its final > - * position and transfers control to the image entry point when the > - * relocation is complete. > + * Both restart and cpu_soft_restart will shutdown the MMU, disable data > + * caches. However, restart will start new kernel or purgatory directly, > + * cpu_soft_restart will transfer control to arm64_relocate_new_kernel > * In kexec case, kimage->start points to purgatory assuming that > * kernel entry and dtb address are embedded in purgatory by > * userspace (kexec-tools). > * In kexec_file case, the kernel starts directly without purgatory. > */ > - cpu_soft_restart(kimage->arch.kern_reloc, kimage->head, kimage->start, > - kimage->arch.dtb_mem); > + if (kimage->head & IND_DONE) { > + typeof(__cpu_soft_restart) *restart; > + > + cpu_install_idmap(); > + restart = (void *)__pa_symbol(function_nocfi(__cpu_soft_restart)); > + restart(is_hyp_nvhe(), kimage->start, kimage->arch.dtb_mem, > + 0, 0); Why can't you call: cpu_soft_restart(kimage->start, kimage->arch.dtb_mem, 0, 0); here instead of open-coding it? Will