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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 1E1D1C77B77 for ; Mon, 17 Apr 2023 14:34:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:From:References:Cc:To: Subject:MIME-Version:Date:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=5XLmHG9qt8aw/M0qBHWaSmbpNCXJppotL6OxulWfjn0=; b=4yMtjYYmhaxjus fRBtmw6r7Hs+7lOE3O781zqpy0h8v78vqtY0Hvt70ZlFWRKZibHTehCjAjpjMNP0wpFXAVI7i9MQj TCOaKB7vEqLcsE0Nvw1w9dCkADQnY4NXf5r17H/59rZtaM1YvVf0Gj1CU7HOk6Zgc8Xpg6N/1H5oe ZCe3WNVpvfnZ7vV0xoBUgLboPIEHhogeogzTCP/f0JAkh4QGp2ZJhmDvUo13riDxWtItoXZQ0Zz7P B0RjR0xPPEaUXdBa51tlMha9UQvbBeSZeupKqPEUyL5Uwqh4hlyjleL8JBE/olt6ZYqkBwzCzd41i A2a+IP10sNEnztWAe3Hg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1poPvf-00Ge6b-0y; Mon, 17 Apr 2023 14:34:03 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1poPvb-00Ge5P-2Q for linux-arm-kernel@lists.infradead.org; Mon, 17 Apr 2023 14:34:01 +0000 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 DA0611063; Mon, 17 Apr 2023 07:34:40 -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 8ACD33F5A1; Mon, 17 Apr 2023 07:33:55 -0700 (PDT) Message-ID: Date: Mon, 17 Apr 2023 15:33:53 +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 Cc: linux-kernel@vger.kernel.org, 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: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230417_073359_833834_E294A35A X-CRM114-Status: GOOD ( 14.35 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 17/04/2023 15:30, Ard Biesheuvel wrote: > On Mon, 17 Apr 2023 at 16:28, Ryan Roberts wrote: >> >> 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? >> > > This (ab)uses the CPU feature framework, which is based on 4-bit > quantities. I don't remember if it matters or not, but IIRC the > default macros use 4-bit wide values. OK, thanks. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel