From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f47.google.com (mail-wm1-f47.google.com [209.85.128.47]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B54F64908CD for ; Mon, 27 Jul 2026 00:10:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.47 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785111057; cv=none; b=UamYnAS/WV+l/X/0nAEd0vx4qE4osap0poHbh75oTtIzP8mr42BM+fvzgphu3ltztTpmPVfK1tdnP9zWmFh3qu7mtV5a44+kyR9oZHyVwPwKsgWCbzdcA7gL09he9FBheggCBy1IgrdJGZOupyqdXGxU/rYQe4Mn1BpbdDMNKPs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785111057; c=relaxed/simple; bh=RM71rEpMshNU/1M43+xs6op/v06TdqK/Y4+1CcbduMo=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=WYVY+kK2Uu4cOSiiIauarabr9LImhZN2d1q2FN248rQHOirrYcBYjw6Gte9tqyI/Dc6ZYBmvEZJ28sLnRqLAT9uzsvdEik/YklG/LAUBG5pVMIkfA2QkYAJDr1kjd/zBXwqkecGW2dWJbkp901iaGlgDwqUsGNNVe9J9cn9sMpw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=hIod66n1; arc=none smtp.client-ip=209.85.128.47 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="hIod66n1" Received: by mail-wm1-f47.google.com with SMTP id 5b1f17b1804b1-4955de8797cso12563825e9.3 for ; Sun, 26 Jul 2026 17:10:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1785111054; x=1785715854; darn=lists.linux.dev; h=in-reply-to:content-disposition:content-type:mime-version :references:message-id:subject:cc:to:from:date:from:to:cc:subject :date:message-id:reply-to:content-type; bh=01dl0IIZWjJRbfIXfFu72Txfn4OJSXE2utImaot0HF4=; b=hIod66n1iAZr8xtK+aH7L+1NG01Tcv/n0mMM839bzavF+xfICtfEkpGNQjq9OjK6El ySUNT0cDIOe75b3qR0NqzraBHpk9rmiGghdP5P2rU008pS9ZRKnNp52L6v4RB0iTK2ml 3r7jt4L13pfZ+jAYVZtPom/6vFBDbQKG44rtNLZVyOc6PX6O8JqZGIVwiggU8/qCKHWI QpF+zB4i3RtF0sfBG2SpNcUnIxNaodVNSIja1tTTqFWcrX6h74+DAiSN9Lgs4Fto55Si cpUM77+GqzYkZVJeTQ4QhlznPRLyt87nQoeRanyp7DqrOB+1PXcnID0+3XecMPKITHRb D+ig== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1785111054; x=1785715854; h=in-reply-to:content-disposition:content-type:mime-version :references:message-id:subject:cc:to:from:date:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=01dl0IIZWjJRbfIXfFu72Txfn4OJSXE2utImaot0HF4=; b=NHmIZRNes1VCs93Q0U0oLLOit39Y0YsRkCM6acr9K84yUJq7W9e0+0PdrUQebj5rtQ qyS7KzuyAw/JssCQrhNwFWyIBo8LWr2+pV7r7K+iUiuvOLC9t0ylHo1NAV896ZuChxuw 6s6XgZtsonhLqAxFQoFSb3NTPmay7b39NN8kaGNYLAAZTPkzhWaeOVMMDZnI9utDd+wW g4gPbY557dPH6xIvoV6ukDD7DPk3lnjwelLm7v2Jbkxm92liMcUO6wPgBbY7aGezQN71 WJoOOH+Fyomxgn+RkI/aF1/xnLLCKP739Bc4mpLNlgSJ1GUQOqQuUPR2MUchI68Y8pc6 dxWg== X-Forwarded-Encrypted: i=1; AHgh+RoziLy/Ic+sTd3A/pWKS2g0P30edeveMokiRvqJuyildXRbU8YTPdtHd2C5o2ikm3sX1RIo@lists.linux.dev X-Gm-Message-State: AOJu0YzNSfXw3n8mfWJ27Ndccrb0EIAxiAc7W23nCB7tJxLCVD16mfFa 6iEzunGhur2z+yJ4oCMvM7BLe+0IvDhvkPGqZ8aoeW9rKfftTXexs0T+ X-Gm-Gg: AR+sD13i+mJWTVc/J67b551/IqJgUPdEuChxkH2JouHCXEaxHGs52uIi4mmn8vZycK6 bS3a1Mqpmombch9pHMbdzDXW6toNfnOHihavNgThcAZFoJMUQus4Sl2TmrAdQlTC1VGawwEVPnp kOp7eDkc2bfb/lm5llSbvtut7JMIaezjZ6ds0aLj1hrxpYiCxCSjx3t4FPy/X4EoV8oaEAuS2Wp TQq8+fidKg8zICM1nckPUohgMUhjHcY3cEYq7Kibc9b/euKZcukD/WPhXAoj4gGXgcGvNtmFJ7T ANLwNYj7caykz1E+twxmFpjt1tMT/DFU6Q2qzC48JuHFTjydfDPqTMEt7T8raa18GAGO1nHhdC5 JnCKqCP7Ub2Fv9z3ux4Z7tXIo4NPkno37gjES/Vps8o1UJsbzX4Y1nIkyUtP4rPeHkab7p1rfNS Zg4KLN8QkdMKjNarBU85bNld7QeStR1ODUb3DLunBSFsLHg3NIY+F7XxYMb9gjWB5EswSU0ZzDe l/iJMzhCIBVT5xuWGs3SNuFWYd8Sri2tMfdL+ycl14= X-Received: by 2002:a05:600c:5492:b0:495:7eab:3abd with SMTP id 5b1f17b1804b1-496b5736f4fmr90983825e9.33.1785111053770; Sun, 26 Jul 2026 17:10:53 -0700 (PDT) Received: from unknown748F3CBA5068 (dynamic-095-114-116-215.95.114.pool.telefonica.de. [95.114.116.215]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-496b4d8d6efsm201357975e9.0.2026.07.26.17.10.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 26 Jul 2026 17:10:52 -0700 (PDT) Date: Mon, 27 Jul 2026 02:10:19 +0200 From: Karl Mehltretter To: Kees Cook Cc: "Russell King (Oracle)" , Linus Walleij , Nathan Chancellor , Sami Tolvanen , Zhen Lei , Arnd Bergmann , =?utf-8?Q?Micha=C5=82?= Pecio , Sebastian Andrzej Siewior , linux-arm-kernel@lists.infradead.org, Russell King , Will Deacon , Mark Rutland , Nick Desaulniers , Bill Wendling , Justin Stitt , linux-kernel@vger.kernel.org, llvm@lists.linux.dev, linux-hardening@vger.kernel.org Subject: Re: [PATCH v3] ARM: traps: Implement KCFI trap handler for ARM32 Message-ID: References: <20260715175223.make.153-kees@kernel.org> Precedence: bulk X-Mailing-List: llvm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260715175223.make.153-kees@kernel.org> On Wed, Jul 15, 2026 at 10:52:27AM +0100, Kees Cook wrote: > +bool arm_cfi_handle_failure(struct pt_regs *regs, enum bug_trap_type type) > +{ > + switch (type) { > + case BUG_TRAP_TYPE_BUG: > + die("Oops - CFI", regs, 0); > + break; > + case BUG_TRAP_TYPE_WARN: > + /* Permissive mode: skip the trapping instruction and continue. */ > + instruction_pointer(regs) += 4; > + break; On Thumb-2, Clang emits a 16-bit BKPT for CFI checks. This skips the following Thumb instruction. Thanks, Karl