From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 89954C7115A for ; Wed, 18 Jun 2025 12:08:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc: To:From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=eIzLatU61BABGI1VibIYf/IsJQn164yHu53a+YCb5SI=; b=PTWKET8pKP+xhsIG9UOC7Kfpac D0E0/Q4lvStnPRRhxYSY+FBDVGmOvIsSjd1vJyg09yzqBj6Zqrx0Xn1YLCuyDQPfvbblXKA5bpv9E MIF07DAz06TX6V3qG5x99CiCIKBmRM+RET0IO/56wTHyetZfjlQnz1jacapX3D4Etr2CgXY2C2Fzn ZAG1FDfRE4aIaAeaHbMwNCR95XlvEnZbYb11zeamBgXd8o5oTTQECIf5mxse1qeRvVNnZODNwrT/5 M/jmgccN/y1YDl0/ItlO82ozadn9r2ne00bR1mDT5JmqoZETVAIJvOI3Ggp8uMuMPPDmRkKaq3Tx0 id03G1wg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uRraq-0000000A4PZ-3YFp; Wed, 18 Jun 2025 12:08:40 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uRpwi-00000009lfT-0blW for linux-arm-kernel@lists.infradead.org; Wed, 18 Jun 2025 10:23:09 +0000 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> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250618_032308_224435_F883AC94 X-CRM114-Status: GOOD ( 15.27 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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’s main role is to measure and appraise files before they are used. This includes measuring critical system files during early boot (e.g., init, init scripts, login binaries). If IMA were a module, it would be loaded too late to cover those. o TPM Dependency: IMA integrates tightly with the TPM to record measurements 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 system could delay or tamper with its initialization. IMA must be built-in to ensure it starts measuring from the earliest possible 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 drivers (tpm_crb and tpm_crb_ffa) also needs to be built-in. However with FF-A driver 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 completes, 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 --- 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/driver.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); static void __exit ffa_exit(void) { -- LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}