From nobody Fri Sep 25 23:09:59 2026 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 100D651C331 for ; Mon, 7 Sep 2026 16:22:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788798152; cv=none; b=Cum7CKdOazzxcuavV1ChKxOY+tRiHh266x8YlO6YvpwSIiGGv2vHrXrqMQlSwik+TVD15j77mtrgsNwpVyWd+szDf5ztlqPiI4wDR41uVbhW1zPctwfjYWH/Y6l0fu0RggeFMz7wwqu9hnSwdk8S3g6AReRAuSSObOk6qD8zExM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788798152; c=relaxed/simple; bh=XAeqWuHc9jnj7EF+rIUKhmu4pAbQvhgD5GDfn5hHh9I=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=GukgIuT+63K3JIUZI0yP6QP7KCWoDSNPn8hzkdSRkr70EuP5DNCwSk5DdPW3l8QHrbAPrDbFFvLenMhCbWwar44sZzUiDMVicxHVuhZ7TI3Sqf07s5dS05CSEy4gbAYqMkfG0UyW8enavhHNw7oCV2Njx8EJpVWefh0GNRl3xzE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=G+J91P19; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="G+J91P19" 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 2F85D1477; Mon, 7 Sep 2026 09:22:19 -0700 (PDT) Received: from ewhatever.cambridge.arm.com (ewhatever.cambridge.arm.com [10.2.197.99]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 0316C3F528; Mon, 7 Sep 2026 09:22:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1788798142; bh=XAeqWuHc9jnj7EF+rIUKhmu4pAbQvhgD5GDfn5hHh9I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=G+J91P19HVXLKxQXd9uRL/DwKTix2YtsSCBzkyKxR8RVFksiU9e5ONFoRnN0cHFb+ r7LbJ6PFOT/WA4xYbR3enBx7EemQ4YVFW9gqTSpCOKZlLAqlVh13rLfOefjg1Pb34H Rp7oau2DGEt7l8MfqiGL0PlM7uZCudjBa2uycWsM= From: Suzuki K Poulose To: linux-arm-kernel@lists.infradead.org Cc: catalin.marinas@arm.com, will@kernel.org, linux-kernel@vger.kernel.org, maz@kernel.org, pavan.kondeti@oss.qualcomm.com, tabba@google.com, aneesh.kumar@kernel.org, mark.rutland@arm.com, sdonthineni@nvidia.com, steven.price@arm.com, gshan@redhat.com, yuzenghui@huawei.com, kvmarm@lists.linux.dev, Suzuki K Poulose Subject: [PATCH v17 1/1] arm64: mm: Handle Granule Protection Faults (GPFs) Date: Mon, 7 Sep 2026 17:22:04 +0100 Message-ID: <20260907162204.1479401-2-suzuki.poulose@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260907162204.1479401-1-suzuki.poulose@arm.com> References: <20260907162204.1479401-1-suzuki.poulose@arm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Steven Price If the host attempts to access granules that have been delegated for use in a realm these accesses will be caught and will trigger a Granule Protection Fault (GPF). A fault during a page walk signals a bug in the kernel and is handled by oopsing the kernel. A non-page walk fault could be caused by user space having access to a page which has been delegated to the kernel and will trigger a SIGBUS to allow debugging why user space is trying to access a delegated page. Also, until we unmap the "private" memory pages from the linear map, we cou= ld get spurious GPFs from within the kernel, e.g., load_unaligned_zeropad(). S= o, try to fix them up for now. Reviewed-by: Suzuki K Poulose Reviewed-by: Gavin Shan Signed-off-by: Steven Price Signed-off-by: Suzuki K Poulose Reviewed-by: Catalin Marinas --- Changes since v16: * Update the commit description to indicate why we try to fixup GPFs Changes since v10: * Don't call arm64_notify_die() in do_gpf() but simply return 1. Changes since v2: * Include missing "Granule Protection Fault at level -1" --- arch/arm64/mm/fault.c | 28 ++++++++++++++++++++++------ 1 file changed, 22 insertions(+), 6 deletions(-) diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index 0b52557652be6..ad00997b1a873 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -910,6 +910,22 @@ static int do_tag_check_fault(unsigned long far, unsig= ned long esr, return 0; } =20 +static int do_gpf_ptw(unsigned long far, unsigned long esr, struct pt_regs= *regs) +{ + const struct fault_info *inf =3D esr_to_fault_info(esr); + + die_kernel_fault(inf->name, far, esr, regs); + return 0; +} + +static int do_gpf(unsigned long far, unsigned long esr, struct pt_regs *re= gs) +{ + if (!is_el1_instruction_abort(esr) && fixup_exception(regs, esr)) + return 0; + + return 1; +} + static const struct fault_info fault_info[] =3D { { do_bad, SIGKILL, SI_KERNEL, "ttbr address size fault" }, { do_bad, SIGKILL, SI_KERNEL, "level 1 address size fault" }, @@ -946,12 +962,12 @@ static const struct fault_info fault_info[] =3D { { do_bad, SIGKILL, SI_KERNEL, "unknown 32" }, { do_alignment_fault, SIGBUS, BUS_ADRALN, "alignment fault" }, { do_bad, SIGKILL, SI_KERNEL, "unknown 34" }, - { do_bad, SIGKILL, SI_KERNEL, "unknown 35" }, - { do_bad, SIGKILL, SI_KERNEL, "unknown 36" }, - { do_bad, SIGKILL, SI_KERNEL, "unknown 37" }, - { do_bad, SIGKILL, SI_KERNEL, "unknown 38" }, - { do_bad, SIGKILL, SI_KERNEL, "unknown 39" }, - { do_bad, SIGKILL, SI_KERNEL, "unknown 40" }, + { do_gpf_ptw, SIGKILL, SI_KERNEL, "level -1 granule protection fault (tr= anslation table walk)" }, + { do_gpf_ptw, SIGKILL, SI_KERNEL, "level 0 granule protection fault (tra= nslation table walk)" }, + { do_gpf_ptw, SIGKILL, SI_KERNEL, "level 1 granule protection fault (tra= nslation table walk)" }, + { do_gpf_ptw, SIGKILL, SI_KERNEL, "level 2 granule protection fault (tra= nslation table walk)" }, + { do_gpf_ptw, SIGKILL, SI_KERNEL, "level 3 granule protection fault (tra= nslation table walk)" }, + { do_gpf, SIGBUS, SI_KERNEL, "granule protection fault" }, { do_bad, SIGKILL, SI_KERNEL, "level -1 address size fault" }, { do_bad, SIGKILL, SI_KERNEL, "unknown 42" }, { do_translation_fault, SIGSEGV, SEGV_MAPERR, "level -1 translation fault= " }, --=20 2.43.0