From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4D3E2307496; Tue, 24 Jun 2025 23:29:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750807773; cv=none; b=CfG8PMoor/yNhfwFoEqbGqb4nyb3iqu/1gJ1bj9dsuufeeejljzL6s/bZOPUc3Dv68NV+hXRiezGU/VYc96TXhRkHwSh2ar2h0Luxp2IxXaAddos9ZJVHIAuVX0Q5AqSM/jvBLjiZlQvjwDr4ebupGtnhIOdrDMh/1KnXe4TUSA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750807773; c=relaxed/simple; bh=05HNQPwBtyrgW26Vc7Vbxtx/maWAq57HxbUh2ZxvJ30=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=O6XhhZXq8q1XYrrd/20UXgs34SvuYctJ4W0468dZJBpMkPZNulnhmuqK0d3Fyh4vM49yzQGU9IOsaFs8+aQPFbRHT67bp+z390/JoaeJXQ64pxrI/GWXjJJccLhlkVmg9BAXZi105ga5ckuJc5uLEZv46Zb5jq4RHeQ/iuDgy6k= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Lxbf109m; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Lxbf109m" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9A0BCC4CEE3; Tue, 24 Jun 2025 23:29:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1750807773; bh=05HNQPwBtyrgW26Vc7Vbxtx/maWAq57HxbUh2ZxvJ30=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Lxbf109mvjbn0TirCG+sCyt/Ame5IbV1g9IA1Uk281WOkYBEqT5INF4ZLGxA8RyxY zjDWHb/aPeSRxTvj9N+lGl1qY3GHih7gWN9bOvsQB7PQ313Gg7GvWWaKVn0KDhKw3y g687ccDbjrB3wMt+6p6Fl79jtMGP1Dthonu1FEqomnou7JuNanxq6gJml/W2FIFtHc 8fJ091giY5xzz2ViYJW5nsIgk14kHTwJ0m4d6jj+TE9VhAS1v+zcLxp9tLW8AXMu47 pS76wLnldyp2MM08loZc8EsKqsU2zc1gdS7xOjuEU6YD9Lt7gRQJ4/RCSU91qAj67i Zco3zMSmyBFOw== Date: Wed, 25 Jun 2025 02:29:29 +0300 From: Jarkko Sakkinen To: Yeoreum Yun Cc: sudeep.holla@arm.com, peterhuewe@gmx.de, jgg@ziepe.ca, stuart.yoder@arm.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-integrity@vger.kernel.org Subject: Re: [PATCH v4 2/2] tpm: tpm_crb_ffa: try to probe tpm_crb_ffa when it's built-in Message-ID: References: <20250618102302.2379029-1-yeoreum.yun@arm.com> <20250618102302.2379029-3-yeoreum.yun@arm.com> Precedence: bulk X-Mailing-List: linux-integrity@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20250618102302.2379029-3-yeoreum.yun@arm.com> On Wed, Jun 18, 2025 at 11:23:02AM +0100, Yeoreum Yun wrote: > To generate the boot_aggregate log in the IMA subsystem using TPM PCR values, > 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 — an FF-A device that provides > the communication interface to the tpm_crb driver — has not yet been 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 by register tpm_crb_ffa driver so that > when tpm_crb_ffa device is created before tpm_crb_ffa_init(), > probe the tpm_crb_ffa device in tpm_crb_ffa_init() to finish probe the > TPM device completely. > > 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 | 19 ++++++++++++++++--- > 1 file changed, 16 insertions(+), 3 deletions(-) > > diff --git a/drivers/char/tpm/tpm_crb_ffa.c b/drivers/char/tpm/tpm_crb_ffa.c > index 4ead61f01299..462fcf610020 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 { > }; > > static struct tpm_crb_ffa *tpm_crb_ffa; > +static struct ffa_driver tpm_crb_ffa_driver; > > static int tpm_crb_ffa_to_linux_errno(int errno) > { > @@ -168,13 +169,23 @@ static int tpm_crb_ffa_to_linux_errno(int errno) > */ > int tpm_crb_ffa_init(void) > { > + int ret = 0; > + > + if (!IS_MODULE(CONFIG_TCG_ARM_CRB_FFA)) { > + ret = ffa_register(&tpm_crb_ffa_driver); > + if (ret) { > + tpm_crb_ffa = ERR_PTR(-ENODEV); > + return ret; > + } > + } > + > if (!tpm_crb_ffa) > - return -ENOENT; > + ret = -ENOENT; > > if (IS_ERR_VALUE(tpm_crb_ffa)) > - return -ENODEV; > + ret = -ENODEV; > > - return 0; > + return ret; > } > EXPORT_SYMBOL_GPL(tpm_crb_ffa_init); > > @@ -369,7 +380,9 @@ static struct ffa_driver tpm_crb_ffa_driver = { > .id_table = tpm_crb_ffa_device_id, > }; > > +#ifdef MODULE > module_ffa_driver(tpm_crb_ffa_driver); > +#endif > > MODULE_AUTHOR("Arm"); > MODULE_DESCRIPTION("TPM CRB FFA driver"); > -- > LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7} > NAK BR, Jarkko