From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6206B243954; Thu, 4 Sep 2025 18:33:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757010783; cv=none; b=QG6kf5XOop9cO7aIsKOOvcKlWMyLFdbZfR4yqTQJZPQh3fGp9JgPBMfUvlNngHhY2hjM09sElFieMexrJRMiiIefIxgaQtuIIp+ePUziyZMqw3uVosj7mGkieHhbjcpwpUudSRd1D0XcmDCCGEfxs309oJ5UGork1gE6FLYOlUM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757010783; c=relaxed/simple; bh=vso1jcuXl4eMsNTY6YtZqzsNKfEUrShjwPxBJ8ib6Q4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=RcNuSDkep2eQRSGURzLldDytpWLXliwyctbA2dUOy5fiKOZG5FtQYYL9YHbAoY5NXnjI1yRGgeAtjBrTbE4/szXpp8AuADd3wnrRlYeKT3CvyFrxjpaieb6QpGF2VPK1B2+mZ+gd9wd6DEicWKpD6kxfC/CY0Digami75/jpb2s= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=UeOB5sfg; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="UeOB5sfg" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 58426C4CEF0; Thu, 4 Sep 2025 18:32:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1757010782; bh=vso1jcuXl4eMsNTY6YtZqzsNKfEUrShjwPxBJ8ib6Q4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=UeOB5sfg1L8tYWhFhqz2+8pjsUnTOpx9cXPDxNx51xZLJCftmeovcMPkXsRvqFICf nDdAqQ76nV20Ej46lnDZ2exe/GQRuCAu/zDKenXuF52NkMVjkwQ60r605Qv2qk0LMT yytrDQgaMSRzgSCACAUVeXN+IG5zpDuFZcB9Vhvs6HgKGjDUd1MNCUkNQdmgoqNuqp 43RQIvazYa3NVw8wSTiBAtqLh5duh+MB7aNAF/nnaIpXB0sZDWpWFEKQ4fp7JucklF x9HuiqWcOi6CRtX6yjY5m/F1zA9+7sbwTErgFA7+xxzsaeuofVvBZfNlk839R4mCVY 682w7KI4IXfvw== Date: Thu, 4 Sep 2025 11:32:54 -0700 From: Nathan Chancellor To: Kees Cook Cc: Peter Zijlstra , Jonathan Corbet , "Paul E. McKenney" , Randy Dunlap , linux-doc@vger.kernel.org, Vegard Nossum , Miguel Ojeda , Linus Walleij , Jeff Johnson , David Woodhouse , "Russell King (Oracle)" , Nick Desaulniers , Bill Wendling , Justin Stitt , Marco Elver , Przemek Kitszel , Ramon de C Valle , Nicolas Schier , Masahiro Yamada , Arnd Bergmann , Krzysztof Kozlowski , Sami Tolvanen , Mark Rutland , linux-kernel@vger.kernel.org, llvm@lists.linux.dev, linux-kbuild@vger.kernel.org, linux-arm-kernel@lists.infradead.org, x86@kernel.org, linux-hardening@vger.kernel.org Subject: Re: [PATCH v2 3/9] x86/cfi: Document the "cfi=" bootparam options Message-ID: <20250904183254.GB2110053@ax162> References: <20250904033217.it.414-kees@kernel.org> <20250904034656.3670313-3-kees@kernel.org> Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250904034656.3670313-3-kees@kernel.org> On Wed, Sep 03, 2025 at 08:46:42PM -0700, Kees Cook wrote: > The kernel-parameters.txt didn't have a section for the cfi= options. > Add it. > > Signed-off-by: Kees Cook > --- Reviewed-by: Nathan Chancellor > --- > Documentation/admin-guide/kernel-parameters.txt | 17 +++++++++++++++++ > 1 file changed, 17 insertions(+) > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > index 747a55abf494..8bbffbb334ab 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -608,6 +608,23 @@ > ccw_timeout_log [S390] > See Documentation/arch/s390/common_io.rst for details. > > + cfi= [X86-64] Set Control Flow Integrity checking features > + when CONFIG_FINEIBT is enabled. > + Format: feature[,feature...] > + Default: auto > + > + auto: Use FineIBT if IBT available, otherwise kCFI. > + Under FineIBT, enable "paranoid" mode when > + FRED is not available. > + off: Turn off CFI checking. > + kcfi: Use kCFI (disable FineIBT). > + fineibt: Use FineIBT (even if IBT not available). > + norand: Do not re-randomize CFI hashes. > + paranoid: Add caller hash checking under FineIBT. > + bhi: Enable register poisoning to stop speculation > + across FineIBT. (Disabled by default.) > + warn: Do not enforce CFI checking: warn only. > + > cgroup_disable= [KNL] Disable a particular controller or optional feature > Format: {name of the controller(s) or feature(s) to disable} > The effects of cgroup_disable=foo are: > -- > 2.34.1 >