From nobody Thu Oct 2 20:44:31 2025 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (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 D7DE9275AE4; Thu, 11 Sep 2025 07:35:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757576102; cv=none; b=FK4KfFK4Uz8zFu0+f48g7gAQpqsv0N9RzeyX4BFI/b4AOnF/kueqrRZQ4oiKD2NiKtLLQ9hANeP9sgDAKnM9pnG7ex2Do9Pore+D6Koh9VaCptXhgULIr1zGwx9V/Z5Za6ykIenKMwxKNJuHmlEiFkrVCYZR0G09Tx2kpnb3H1g= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757576102; c=relaxed/simple; bh=jjU4nHnj9IMtYuEp6wG6Wwy6AqwCP5xkECHMrgYHRhg=; h=Date:From:To:Subject:Cc:MIME-Version:Message-ID:Content-Type; b=tJMb0uRsGghN+6OcOOvhtclfX5izTGcDQbQCiQJ9/GdOM7FtROScKANQGoPZJHz8McCtjfmYwqvLgLbfDXgYJ+uHFdd3AjWto0ODbzdCbMix9MSmVMvc5ZKX5S+AOj0DgkKHoE9Qyxqw7f2Vux6tc5i5m/XGY/4SbiOArxrD3MU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=tCBdzlEv; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=gDBkS0x3; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="tCBdzlEv"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="gDBkS0x3" Date: Thu, 11 Sep 2025 07:34:57 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1757576099; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=SFZQgdbSQetdpkSR55ZM4/R7upcnTwzCYh/AbXaQBcE=; b=tCBdzlEvaMoVY0N5EreWFVfoAHj39dWj6WeAp/WPTgo5VgjMmxh394Lr3MD7UhQO8X6NE6 UfETm7v01NYXtOUxgihL44OYp3kePPPN1hA46NF4vUqbSemudKdQxCCJJLfJNH3ddEZQBq seWl5EzD7nzRC7bIKGs9q3Aww8VXuLj2p4EgNcC//2rVUKHGuNpaUHXgHDwW0AW+iK3Fdx B0Jy8yUsngnl2zRf0E9JVxI80UU/GUyITrzEpDnYp3MKpAVhNctXhawJeAhLYmIfn6W51B ybZmiLfzrn02jp/h2AMQbhWgIcbBO/aG79/9WErfezcionMmK9ogbs9NDuDnJQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1757576099; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=SFZQgdbSQetdpkSR55ZM4/R7upcnTwzCYh/AbXaQBcE=; b=gDBkS0x3CC51+mV2ElJ003LI+85da8wlhOF8Z3RC1lMveKjeTGbxRumKDcx/eWI5Rm+st8 k1so/lyBdvEI3KCw== From: "tip-bot2 for Kees Cook" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: x86/core] x86/cfi: Document the "cfi=" bootparam options Cc: Kees Cook , "Peter Zijlstra (Intel)" , Nathan Chancellor , x86@kernel.org, linux-kernel@vger.kernel.org Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-ID: <175757609765.709179.2818869098867903879.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Precedence: bulk Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable The following commit has been merged into the x86/core branch of tip: Commit-ID: 24452d9ef17502965021ce5df30f4e184245a5ac Gitweb: https://git.kernel.org/tip/24452d9ef17502965021ce5df30f4e184= 245a5ac Author: Kees Cook AuthorDate: Wed, 03 Sep 2025 20:46:42 -07:00 Committer: Peter Zijlstra CommitterDate: Thu, 04 Sep 2025 21:59:08 +02:00 x86/cfi: Document the "cfi=3D" bootparam options The kernel-parameters.txt didn't have a section for the cfi=3D options. Add it. Signed-off-by: Kees Cook Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Nathan Chancellor Link: https://lore.kernel.org/r/20250904034656.3670313-3-kees@kernel.org --- Documentation/admin-guide/kernel-parameters.txt | 17 ++++++++++++++++- 1 file changed, 17 insertions(+) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentatio= n/admin-guide/kernel-parameters.txt index 747a55a..8bbffbb 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. =20 + cfi=3D [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=3D [KNL] Disable a particular controller or optional featu= re Format: {name of the controller(s) or feature(s) to disable} The effects of cgroup_disable=3Dfoo are: