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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D865CC77B76 for ; Mon, 17 Apr 2023 14:28:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229825AbjDQO2y (ORCPT ); Mon, 17 Apr 2023 10:28:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54118 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230355AbjDQO2v (ORCPT ); Mon, 17 Apr 2023 10:28:51 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 81BDC5B9B for ; Mon, 17 Apr 2023 07:28:50 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id EDA7B1063; Mon, 17 Apr 2023 07:29:33 -0700 (PDT) Received: from [10.57.68.227] (unknown [10.57.68.227]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 08EBE3F5A1; Mon, 17 Apr 2023 07:28:48 -0700 (PDT) Message-ID: Date: Mon, 17 Apr 2023 15:28:47 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.9.1 Subject: Re: [PATCH v3 30/60] arm64: idreg-override: Create a pseudo feature for rodata=off Content-Language: en-US To: Ard Biesheuvel , linux-kernel@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org, Catalin Marinas , Will Deacon , Marc Zyngier , Mark Rutland , Anshuman Khandual , Kees Cook References: <20230307140522.2311461-1-ardb@kernel.org> <20230307140522.2311461-31-ardb@kernel.org> From: Ryan Roberts In-Reply-To: <20230307140522.2311461-31-ardb@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/03/2023 14:04, Ard Biesheuvel wrote: > Add rodata=off to the set of kernel command line options that is parsed > early using the CPU feature override detection code, so we can easily > refer to it when creating the kernel mapping. > > Signed-off-by: Ard Biesheuvel > --- > arch/arm64/include/asm/cpufeature.h | 1 + > arch/arm64/kernel/pi/idreg-override.c | 2 ++ > 2 files changed, 3 insertions(+) > > diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h > index bc10098901808c00..edc7733aa49846b2 100644 > --- a/arch/arm64/include/asm/cpufeature.h > +++ b/arch/arm64/include/asm/cpufeature.h > @@ -16,6 +16,7 @@ > #define cpu_feature(x) KERNEL_HWCAP_ ## x > > #define ARM64_SW_FEATURE_OVERRIDE_NOKASLR 0 > +#define ARM64_SW_FEATURE_OVERRIDE_RODATA_OFF 4 I assume these are bit numbers? Why not just use the next available bit (bit 1) for this new flag? > > #ifndef __ASSEMBLY__ > > diff --git a/arch/arm64/kernel/pi/idreg-override.c b/arch/arm64/kernel/pi/idreg-override.c > index 4e76db6eb72c2087..6c547cccaf6a9e9c 100644 > --- a/arch/arm64/kernel/pi/idreg-override.c > +++ b/arch/arm64/kernel/pi/idreg-override.c > @@ -151,6 +151,7 @@ static const struct ftr_set_desc sw_features __prel64_initconst = { > .override = &arm64_sw_feature_override, > .fields = { > FIELD("nokaslr", ARM64_SW_FEATURE_OVERRIDE_NOKASLR, NULL), > + FIELD("rodataoff", ARM64_SW_FEATURE_OVERRIDE_RODATA_OFF, NULL), > {} > }, > }; > @@ -183,6 +184,7 @@ static const struct { > "id_aa64isar2.gpa3=0 id_aa64isar2.apa3=0" }, > { "arm64.nomte", "id_aa64pfr1.mte=0" }, > { "nokaslr", "arm64_sw.nokaslr=1" }, > + { "rodata=off", "arm64_sw.rodataoff=1" }, > }; > > static int __init parse_hexdigit(const char *p, u64 *v)