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Date:   Fri, 8 Feb 2019 13:50:31 +0200
From:   Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To:     Stefan Berger <stefanb@linux.ibm.com>
Cc:     Alexander Steffen <Alexander.Steffen@infineon.com>,
        linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-security-module@vger.kernel.org,
        Peter Huewe <PeterHuewe@gmx.de>,
        Jason Gunthorpe <jgg@ziepe.ca>,
        Tomas Winkler <tomas.winkler@intel.com>,
        Tadeusz Struk <tadeusz.struk@intel.com>,
        Stefan Berger <stefanb@linux.vnet.ibm.com>,
        Nayna Jain <nayna@linux.ibm.com>
Subject: Re: [PATCH v11 00/16] Remove nested TPM operations
Message-ID: <20190208115031.GB11755@linux.intel.com>
References: <20190205224723.19671-1-jarkko.sakkinen@linux.intel.com>
 <20190206120634.GA4680@linux.intel.com>
 <3d6fdcc1-8221-2137-fc82-596377cc2fdc@infineon.com>
 <20190207212912.GD23906@linux.intel.com>
 <0af40351-91d5-d0a7-2965-0a9c6505af79@linux.ibm.com>
 <20190208003314.GB7202@linux.intel.com>
 <1fbd29ad-1005-8450-4c39-00974468183b@linux.ibm.com>
 <9cd734ad-ea9d-77f7-b657-3f0910a9d92f@linux.ibm.com>
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On Thu, Feb 07, 2019 at 09:14:54PM -0500, Stefan Berger wrote:
> +EXPORT_SYMBOL_GPL(tpm_chip_start);
> 
> ?/**
> ? * tpm_chip_stop() - power off the TPM
> @@ -131,7 +132,7 @@ void tpm_chip_stop(struct tpm_chip *chip)
> ???? if (chip->ops->clk_enable)
> ???? ??? chip->ops->clk_enable(chip, false);
> ?}
> -
> +EXPORT_SYMBOL_GPL(tpm_chip_stop);

These are already fixed.

> ?/**
> ? * tpm_try_get_ops() - Get a ref to the tpm_chip
> @@ -474,8 +475,11 @@ static void tpm_del_char_device(struct tpm_chip *chip)
> 
> ???? /* Make the driver uncallable. */
> ???? down_write(&chip->ops_sem);
> -??? if (chip->flags & TPM_CHIP_FLAG_TPM2)
> +??? if (chip->flags & TPM_CHIP_FLAG_TPM2) {
> +??? ??? tpm_chip_start(chip, 0);
> ???? ??? tpm2_shutdown(chip, TPM2_SU_CLEAR);
> +??? ??? tpm_chip_stop(chip, 0);
> +??? }

Thanks!

Needs to be also done in tpm_pm_suspend() but there it is also better to
take locks because in-kernel subsystem might be using TPM even user
space has been freezed (e.g. hibernate possibly in future).

mutex_lock(&chip->tpm_mutex);
if (!tpm_chip_start(chip, 0)) {
	tpm2_shutdown(chip, TPM2_SU_CLEAR);
	tpm_chip_stop(chip, 0);
}
mutex_unlock(&chip->tpm_mutex);

Fixed now.

> ???? chip->ops = NULL;
> ???? up_write(&chip->ops_sem);
> ?}
> diff --git a/drivers/char/tpm/tpm-interface.c
> b/drivers/char/tpm/tpm-interface.c
> index 02e8cffd1163..fcd845ad8c3c 100644
> --- a/drivers/char/tpm/tpm-interface.c
> +++ b/drivers/char/tpm/tpm-interface.c
> @@ -124,6 +124,8 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip,
> void *buf, size_t bufsiz)
> ???? ??? dev_err(&chip->dev, "tpm_transmit: tpm_recv: error %d\n", rc);
> ???? } else if (len < TPM_HEADER_SIZE || len != be32_to_cpu(header->length))
> ???? ??? rc = -EFAULT;
> +??? else
> +??? ??? rc = 0;

Why is this needed?

/Jarkko