From nobody Thu Oct 9 11:03:36 2025 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id AA002253941; Wed, 18 Jun 2025 10:23:08 +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=1750242190; cv=none; b=oFVB4L5surYQtOdJ++dp2u9nJFPFxg+2YowCmblRH5b2fuXgzV8oCiZeGAsKDQi3Jf5URqDNirV3+4g1m37vQzJRDP5gJWBE/tbONMZwwf5qc2ab+DEj4N7sjM7RYTKP6ctRcGXkJqJXP/xNWm+KIluZ2g9nhCF2U0N9CKDzvVo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750242190; c=relaxed/simple; bh=XFETnRwJszuY33IPOx4LdCSnsksBJu52kllSSQvTpnE=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Type; b=G99zXebeySisrHaAdzQAKzhkXIhJvdmP7pt1iLdC8umGgyxpdmfiY1fCb+g0rNIezhj7nuTMq5BJCQ3EkJeBcLwezQ42HLORY6AG7f8p/unmieI9GkQa/FbiwZDHwUYETmysKigIrK9zTtq4lue40RxXkdkeilps0VI/JC8vFtM= 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 418281BC0; Wed, 18 Jun 2025 03:22:47 -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 78ADB3F66E; Wed, 18 Jun 2025 03:23:06 -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 v4 1/2] firmware: arm_ffa: Change initcall level of ffa_init() to rootfs_initcall Date: Wed, 18 Jun 2025 11:23:01 +0100 Message-Id: <20250618102302.2379029-2-yeoreum.yun@arm.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20250618102302.2379029-1-yeoreum.yun@arm.com> References: <20250618102302.2379029-1-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 The Linux IMA (Integrity Measurement Architecture) subsystem used for secure boot, file integrity, or remote attestation cannot be a loadable module for few reasons listed below: o Boot-Time Integrity: IMA=E2=80=99s main role is to measure and appraise = files before they are used. This includes measuring critical system files duri= ng early boot (e.g., init, init scripts, login binaries). If IMA were a mod= ule, it would be loaded too late to cover those. o TPM Dependency: IMA integrates tightly with the TPM to record measuremen= ts into PCRs. The TPM must be initialized early (ideally before init_ima()), which aligns with IMA being built-in. o Security Model: IMA is part of a Trusted Computing Base (TCB). Making it= a module would weaken the security model, as a potentially compromised sys= tem could delay or tamper with its initialization. IMA must be built-in to ensure it starts measuring from the earliest possib= le point in boot which inturn implies TPM must be initialised and ready to use before IMA. To enable integration of tpm_event_log with the IMA subsystem, the TPM driv= ers (tpm_crb and tpm_crb_ffa) also needs to be built-in. However with FF-A driv= er also being initialised at device initcall level, it can lead to an initialization order issue where: - crb_acpi_driver_init() may run before tpm_crb_ffa_driver()_init and ffa_= init() - As a result, probing the TPM device via CRB over FFA is deferred - ima_init() (called as a late initcall) runs before deferred probe comple= tes, IMA fails to find the TPM and logs the below error: | ima: No TPM chip found, activating TPM-bypass! Eventually it fails to generate boot_aggregate with PCR values. Because of the above stated dependency, the ffa driver needs to initialised before tpm_crb_ffa module to ensure IMA finds the TPM successfully when present. Signed-off-by: Yeoreum Yun Acked-by: Jarkko Sakkinen Reviewed-by: Mimi Zohar --- drivers/firmware/arm_ffa/driver.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/firmware/arm_ffa/driver.c b/drivers/firmware/arm_ffa/d= river.c index fe55613a8ea9..1a690b8186df 100644 --- a/drivers/firmware/arm_ffa/driver.c +++ b/drivers/firmware/arm_ffa/driver.c @@ -2058,7 +2058,7 @@ static int __init ffa_init(void) kfree(drv_info); return ret; } -module_init(ffa_init); +rootfs_initcall(ffa_init); =20 static void __exit ffa_exit(void) { --=20 LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}