From nobody Sat Oct 11 08:30:49 2025 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id F1F4A26157E; Wed, 11 Jun 2025 11:24:55 +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=1749641097; cv=none; b=lR0zOge1y1n1sTlcHJgWJnPtroC+env6YGUVjoz1QwbqkzP6EM64CqnIR3GOtPMK8GGLzcJIGJyo6Rv1UEyWDiXMPKjK3WL0G4P1WVwLyOQ+RbHGF0e2LikunPEl8IYozI7ivyLUdrMc514svUHt5+90rs151XLMpMYKO0lMORU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749641097; c=relaxed/simple; bh=CF/MUxGhw96kEox5MVRZY8BzNOEV4A+mER0fmPLfrhw=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Type; b=BA2mHAK5xM1wwyY14puMlerAWkO+tKjT3KDfc3rAwJkhq+l5wMPpdlTb6Hzmiv+hXwswCDsJRP0YC2vL+iWNo10OTdCLLYb2x9F/JMCimyJ/1ywIkMryJIe6tqWEl1LciKyfrOSq8CCB/AbJqYgWrw1CB1qaIWAY4ETaEIVB8pQ= 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; 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 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 BFAF82BCD; Wed, 11 Jun 2025 04:24:35 -0700 (PDT) Received: from e129823.cambridge.arm.com (e129823.arm.com [10.1.197.6]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 030553F59E; Wed, 11 Jun 2025 04:24:53 -0700 (PDT) From: Yeoreum Yun To: jarkko@kernel.org, sudeep.holla@arm.com, peterhuewe@gmx.de, jgg@ziepe.ca, stuart.yoder@arm.com Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-integrity@vger.kernel.org, Yeoreum Yun Subject: [PATCH v3 2/2] tpm: tpm_crb_ffa: try to probe tpm_crb_ffa when it's built-in Date: Wed, 11 Jun 2025 12:24:48 +0100 Message-Id: <20250611112448.17751-3-yeoreum.yun@arm.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20250611112448.17751-1-yeoreum.yun@arm.com> References: <20250611112448.17751-1-yeoreum.yun@arm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable To generate the boot_aggregate log in the IMA subsystem using TPM PCR value= s, the TPM driver must be built as built-in and must be probed before the IMA subsystem is initialized. However, when the TPM device operates over the FF-A protocol using the CRB = interface, probing fails and returns -EPROBE_DEFER if the tpm_crb_ffa device =E2=80=94 an FF-A device that provides the communication interface to the tpm_crb driver =E2=80=94 has not yet bee= n probed. This issue occurs because both crb_acpi_driver_init() and tpm_crb_ffa_driver_init() are registered with device_initcall. As a result, crb_acpi_driver_init() may be invoked before tpm_crb_ffa_driver_init(), which is responsible for probing the tpm_crb_ffa= device. When this happens, IMA fails to detect the TPM device and logs the following message: | ima: No TPM chip found, activating TPM-bypass! Consequently, it cannot generate the boot_aggregate log with the PCR values provided by the TPM. To resolve this issue, the tpm_crb_ffa_init() function explicitly attempts = to probe the tpm_crb_ffa. This ensures that the TPM device using CRB over FF-A can be successfully probed, even if crb_acpi_driver_init() is called first. Signed-off-by: Yeoreum Yun --- drivers/char/tpm/tpm_crb_ffa.c | 22 +++++++++++++++++----- 1 file changed, 17 insertions(+), 5 deletions(-) diff --git a/drivers/char/tpm/tpm_crb_ffa.c b/drivers/char/tpm/tpm_crb_ffa.c index 4ead61f01299..2ef29b66fa5d 100644 --- a/drivers/char/tpm/tpm_crb_ffa.c +++ b/drivers/char/tpm/tpm_crb_ffa.c @@ -115,6 +115,7 @@ struct tpm_crb_ffa { }; =20 static struct tpm_crb_ffa *tpm_crb_ffa; +static struct ffa_driver tpm_crb_ffa_driver; =20 static int tpm_crb_ffa_to_linux_errno(int errno) { @@ -168,13 +169,22 @@ static int tpm_crb_ffa_to_linux_errno(int errno) */ int tpm_crb_ffa_init(void) { - if (!tpm_crb_ffa) - return -ENOENT; + int ret =3D 0; =20 - if (IS_ERR_VALUE(tpm_crb_ffa)) - return -ENODEV; + if (IS_MODULE(CONFIG_TCG_ARM_CRB_FFA)) { + if (!tpm_crb_ffa) + ret =3D -ENOENT; =20 - return 0; + if (IS_ERR_VALUE(tpm_crb_ffa)) + ret =3D -ENODEV; + + return ret; + } + + ret =3D ffa_register(&tpm_crb_ffa_driver); + BUG_ON(!ret && !tpm_crb_ffa); + + return ret; } EXPORT_SYMBOL_GPL(tpm_crb_ffa_init); =20 @@ -369,7 +379,9 @@ static struct ffa_driver tpm_crb_ffa_driver =3D { .id_table =3D tpm_crb_ffa_device_id, }; =20 +#ifdef MODULE module_ffa_driver(tpm_crb_ffa_driver); +#endif =20 MODULE_AUTHOR("Arm"); MODULE_DESCRIPTION("TPM CRB FFA driver"); --=20 LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}