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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 9CA17C3F2CE for ; Thu, 5 Mar 2020 03:20:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 75A9F2064A for ; Thu, 5 Mar 2020 03:20:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725903AbgCEDUr (ORCPT ); Wed, 4 Mar 2020 22:20:47 -0500 Received: from szxga07-in.huawei.com ([45.249.212.35]:48086 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725797AbgCEDUr (ORCPT ); Wed, 4 Mar 2020 22:20:47 -0500 Received: from DGGEMS403-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id D406473EA218C9E97C2D; Thu, 5 Mar 2020 11:20:45 +0800 (CST) Received: from [127.0.0.1] (10.173.221.195) by DGGEMS403-HUB.china.huawei.com (10.3.19.203) with Microsoft SMTP Server id 14.3.439.0; Thu, 5 Mar 2020 11:20:39 +0800 Subject: Re: [PATCH v3 5/6] powerpc/fsl_booke/64: clear the original kernel if randomized To: Scott Wood , , , , , , , , , CC: , References: <20200206025825.22934-1-yanaijie@huawei.com> <20200206025825.22934-6-yanaijie@huawei.com> <5737c82b1ab4c80e53904e4846694884ca429569.camel@buserror.net> From: Jason Yan Message-ID: <71e25bac-bdf6-a754-c0f8-c9d99a393085@huawei.com> Date: Thu, 5 Mar 2020 11:20:38 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:68.0) Gecko/20100101 Thunderbird/68.4.2 MIME-Version: 1.0 In-Reply-To: <5737c82b1ab4c80e53904e4846694884ca429569.camel@buserror.net> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.173.221.195] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 在 2020/3/5 5:53, Scott Wood 写道: > On Thu, 2020-02-06 at 10:58 +0800, Jason Yan wrote: >> The original kernel still exists in the memory, clear it now. >> >> Signed-off-by: Jason Yan >> Cc: Scott Wood >> Cc: Diana Craciun >> Cc: Michael Ellerman >> Cc: Christophe Leroy >> Cc: Benjamin Herrenschmidt >> Cc: Paul Mackerras >> Cc: Nicholas Piggin >> Cc: Kees Cook >> --- >> arch/powerpc/mm/nohash/kaslr_booke.c | 4 +++- >> 1 file changed, 3 insertions(+), 1 deletion(-) >> >> diff --git a/arch/powerpc/mm/nohash/kaslr_booke.c >> b/arch/powerpc/mm/nohash/kaslr_booke.c >> index c6f5c1db1394..ed1277059368 100644 >> --- a/arch/powerpc/mm/nohash/kaslr_booke.c >> +++ b/arch/powerpc/mm/nohash/kaslr_booke.c >> @@ -378,8 +378,10 @@ notrace void __init kaslr_early_init(void *dt_ptr, >> phys_addr_t size) >> unsigned int *__kaslr_offset = (unsigned int *)(KERNELBASE + 0x58); >> unsigned int *__run_at_load = (unsigned int *)(KERNELBASE + 0x5c); >> >> - if (*__run_at_load == 1) >> + if (*__run_at_load == 1) { >> + kaslr_late_init(); >> return; >> + } > > What if you're here because kexec set __run_at_load (or > CONFIG_RELOCATABLE_TEST is enabled), not because kaslr happened? > Nothing will happen because kaslr_late_init() only clears memory when kernstart_virt_addr is not KERNELBASE. When __run_at_load is set then KASLR will not take effect. > -Scott > > > > . >