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=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 E52FAC433DB for ; Mon, 8 Mar 2021 10:34:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AE265651A5 for ; Mon, 8 Mar 2021 10:34:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231143AbhCHKdn (ORCPT ); Mon, 8 Mar 2021 05:33:43 -0500 Received: from mga11.intel.com ([192.55.52.93]:65129 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231195AbhCHKd3 (ORCPT ); Mon, 8 Mar 2021 05:33:29 -0500 IronPort-SDR: EoydsZvAOwv0Ae03kvTUtA2gJzc0phExPZxqM8zqv/9V/LPeZ2ipYiaXCGG9awQiRVsIFFpPaT gXRMOLbcWhOw== X-IronPort-AV: E=McAfee;i="6000,8403,9916"; a="184639094" X-IronPort-AV: E=Sophos;i="5.81,232,1610438400"; d="scan'208";a="184639094" Received: from orsmga002.jf.intel.com ([10.7.209.21]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Mar 2021 02:33:28 -0800 IronPort-SDR: HhyRFaji92hkYH/IcTXTNVLyKx6k6Odu/UMT+FJ39Nx8CtWciGdUn4pWzakHR/WhgpUNa5PyfH lQDyY3cFkM6w== X-IronPort-AV: E=Sophos;i="5.81,232,1610438400"; d="scan'208";a="385807735" Received: from smile.fi.intel.com (HELO smile) ([10.237.68.40]) by orsmga002-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Mar 2021 02:33:26 -0800 Received: from andy by smile with local (Exim 4.94) (envelope-from ) id 1lJDCV-00An4O-2k; Mon, 08 Mar 2021 12:33:23 +0200 Date: Mon, 8 Mar 2021 12:33:23 +0200 From: Andy Shevchenko To: Marco Elver Cc: linux-kernel@vger.kernel.org, vbabka@suse.cz, timur@kernel.org, pmladek@suse.com, rostedt@goodmis.org, sergey.senozhatsky@gmail.com, linux@rasmusvillemoes.dk, Geert Uytterhoeven Subject: Re: [PATCH 2/2] lib/vsprintf: reduce space taken by no_hash_pointers warning Message-ID: References: <20210305194206.3165917-1-elver@google.com> <20210305194206.3165917-2-elver@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210305194206.3165917-2-elver@google.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Mar 05, 2021 at 08:42:06PM +0100, Marco Elver wrote: > Move the no_hash_pointers warning string into __initconst section, so > that it is discarded after init. Remove common start/end characters. > Also remove repeated lines from the array, since the compiler can't > remove duplicate strings for us since the array must appear in > __initconst as defined. > > Note, a similar message appears in kernel/trace/trace.c, but compiling > the feature is guarded by CONFIG_TRACING. It is not immediately obvious > if a space-concious kernel would prefer CONFIG_TRACING=n. Therefore, it > makes sense to keep the message for no_hash_pointers as __initconst, and > not move the NOTICE-printing to a common function. This seems to have 2-in-1 patch. Care to split? Feel free to add Reviewed-by: Andy Shevchenko to the __initconst part, but the rest. > Link: https://lkml.kernel.org/r/CAMuHMdULKZCJevVJcp7TxzLdWLjsQPhE8hqxhnztNi9bjT_cEw@mail.gmail.com > Reported-by: Geert Uytterhoeven > Signed-off-by: Marco Elver > --- > lib/vsprintf.c | 30 +++++++++++++++++------------- > 1 file changed, 17 insertions(+), 13 deletions(-) > > diff --git a/lib/vsprintf.c b/lib/vsprintf.c > index 4a14889ccb35..1095689c9c97 100644 > --- a/lib/vsprintf.c > +++ b/lib/vsprintf.c > @@ -2094,26 +2094,30 @@ char *fwnode_string(char *buf, char *end, struct fwnode_handle *fwnode, > bool no_hash_pointers __ro_after_init; > EXPORT_SYMBOL_GPL(no_hash_pointers); > > +static const char no_hash_pointers_warning[8][55] __initconst = { > + "******************************************************", > + " NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE ", > + " This system shows unhashed kernel memory addresses ", > + " via the console, logs, and other interfaces. This ", > + " might reduce the security of your system. ", > + " If you see this message and you are not debugging ", > + " the kernel, report this immediately to your system ", > + " administrator! ", > +}; > + > static int __init no_hash_pointers_enable(char *str) > { > + /* Indices into no_hash_pointers_warning; -1 is an empty line. */ > + const int lines[] = { 0, 1, -1, 2, 3, 4, -1, 5, 6, 7, -1, 1, 0 }; > + int i; > + > if (no_hash_pointers) > return 0; > > no_hash_pointers = true; > > - pr_warn("**********************************************************\n"); > - pr_warn("** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **\n"); > - pr_warn("** **\n"); > - pr_warn("** This system shows unhashed kernel memory addresses **\n"); > - pr_warn("** via the console, logs, and other interfaces. This **\n"); > - pr_warn("** might reduce the security of your system. **\n"); > - pr_warn("** **\n"); > - pr_warn("** If you see this message and you are not debugging **\n"); > - pr_warn("** the kernel, report this immediately to your system **\n"); > - pr_warn("** administrator! **\n"); > - pr_warn("** **\n"); > - pr_warn("** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **\n"); > - pr_warn("**********************************************************\n"); > + for (i = 0; i < ARRAY_SIZE(lines); i++) > + pr_warn("**%54s**\n", i == -1 ? "" : no_hash_pointers_warning[lines[i]]); > > return 0; > } > -- > 2.30.1.766.gb4fecdf3b7-goog > -- With Best Regards, Andy Shevchenko