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=-10.0 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 24155C433E0 for ; Mon, 1 Feb 2021 13:05:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EA97264DDD for ; Mon, 1 Feb 2021 13:05:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231289AbhBANEz (ORCPT ); Mon, 1 Feb 2021 08:04:55 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38614 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229500AbhBANEn (ORCPT ); Mon, 1 Feb 2021 08:04:43 -0500 Received: from pandora.armlinux.org.uk (pandora.armlinux.org.uk [IPv6:2001:4d48:ad52:32c8:5054:ff:fe00:142]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4FADEC061573 for ; Mon, 1 Feb 2021 05:03:48 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=jSruJqvqP42oOvDzzH5lMZkOJMAUz4mT9HH4X7kw/C4=; b=JHqW05K5DJteLosCaiMf13Anp uAEAa2U97sBs5ZlGgUTl8pyHWVurURJGWoFGamVwI6L77AQuAgKwo/AQ7TVYR5qIs9KBQgHeS9Bje yJ0aLiTmFvNZMFo2jWIe9on9VAmz9X4UXEvL6yLUSYo5C6G4rzJbBPDwzmiy5Pz+qSzNprr27YIqi qpucIE+YIcJLSpjjA5KN8cOVyWHxo6EXSYF1R+VlDjHquedK1pC4a+IrbGk6MJoL8Q2h5bPcw46fP XOehEoeSx8H8b7popZKi5rdzcqv6rYs+olXasKST6hJz69c44serqGaSpbcQKAjhWtLAq84oZjFf8 ZvOEF3QMw==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:37756) by pandora.armlinux.org.uk with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1l6Yrp-0003LN-W4; Mon, 01 Feb 2021 13:03:46 +0000 Received: from linux by shell.armlinux.org.uk with local (Exim 4.92) (envelope-from ) id 1l6Yrp-00021n-1z; Mon, 01 Feb 2021 13:03:45 +0000 Date: Mon, 1 Feb 2021 13:03:45 +0000 From: Russell King - ARM Linux admin To: Mark Rutland Cc: Giancarlo Ferrari , linux-kernel@vger.kernel.org, penberg@kernel.org, geert@linux-m68k.org, linux-arm-kernel@lists.infradead.org, akpm@linux-foundation.org, rppt@kernel.org, giancarlo.ferrari@nokia.com Subject: Re: [PATCH] ARM: kexec: Fix panic after TLB are invalidated Message-ID: <20210201130344.GF1463@shell.armlinux.org.uk> References: <1612140296-12546-1-git-send-email-giancarlo.ferrari89@gmail.com> <20210201124720.GA66060@C02TD0UTHF1T.local> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210201124720.GA66060@C02TD0UTHF1T.local> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: Russell King - ARM Linux admin Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Feb 01, 2021 at 12:47:20PM +0000, Mark Rutland wrote: > 1. copy reloc code into buffer > 2. alter variables in copy of reloc code > 3. branch to buffer > > ... which would avoid this class of problem too. Yep, slightly messy to do though: diff --git a/arch/arm/kernel/machine_kexec.c b/arch/arm/kernel/machine_kexec.c index 5d84ad333f05..6058e0d3a40d 100644 --- a/arch/arm/kernel/machine_kexec.c +++ b/arch/arm/kernel/machine_kexec.c @@ -174,18 +174,27 @@ void machine_kexec(struct kimage *image) reboot_code_buffer = page_address(image->control_code_page); - /* Prepare parameters for reboot_code_buffer*/ - set_kernel_text_rw(); - kexec_start_address = image->start; - kexec_indirection_page = page_list; - kexec_mach_type = machine_arch_type; - kexec_boot_atags = image->arch.kernel_r2; - /* copy our kernel relocation code to the control code page */ reboot_entry = fncpy(reboot_code_buffer, &relocate_new_kernel, relocate_new_kernel_size); +#define set(what, val) \ + do { \ + uintptr_t __funcp_address; \ + int __offset; \ + void *__ptr; \ + asm("" : "=r" (__funcp_address) : "0" (&relocate_new_kernel)); \ + __offset = (uintptr_t)&(what) - (__funcp_address & ~1); \ + __ptr = reboot_code_buffer + __offset; \ + *(__typeof__(&(what)))__ptr = val; \ + } while (0) + + set(kexec_start_address, image->start); + set(kexec_indirection_page, page_list); + set(kexec_mach_type, machine_arch_type); + set(kexec_boot_atags, image->arch.kernel_r2); + /* get the identity mapping physical address for the reboot code */ reboot_entry_phys = virt_to_idmap(reboot_entry); -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!