linux-kernel - Re: [PATCH v11 13/14] tpm, tpm_tis: startup chip before testing for interrupts

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Date:   Sun, 4 Dec 2022 17:01:56 +0000
From:   Jarkko Sakkinen <jarkko@...nel.org>
To:     Lino Sanfilippo <LinoSanfilippo@....de>
Cc:     peterhuewe@....de, jgg@...pe.ca, stefanb@...ux.vnet.ibm.com,
        linux@...ewoehner.de, linux-integrity@...r.kernel.org,
        linux-kernel@...r.kernel.org, jandryuk@...il.com,
        pmenzel@...gen.mpg.de, l.sanfilippo@...bus.com, lukas@...ner.de,
        p.rosenberger@...bus.com
Subject: Re: [PATCH v11 13/14] tpm, tpm_tis: startup chip before testing for
 interrupts

On Thu, Nov 24, 2022 at 02:55:37PM +0100, Lino Sanfilippo wrote:
> From: Lino Sanfilippo <l.sanfilippo@...bus.com>
> 
> In tpm_tis_gen_interrupt() a request for a property value is sent to the
> TPM to test if interrupts are generated. However after a power cycle the
> TPM responds with TPM_RC_INITIALIZE which indicates that the TPM is not
> yet properly initialized.
> Fix this by first starting the TPM up before the request is sent. For this
> the startup implementation is removed from tpm_chip_register() and put
> into the new function tpm_chip_startup() which is called before the
> interrupts are tested.
> 
> Signed-off-by: Lino Sanfilippo <l.sanfilippo@...bus.com>
> ---
>  drivers/char/tpm/tpm-chip.c     | 38 +++++++++++++++++++++------------
>  drivers/char/tpm/tpm.h          |  1 +
>  drivers/char/tpm/tpm_tis_core.c |  5 +++++
>  3 files changed, 30 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
> index 783d65fc71f0..370aa1f529f2 100644
> --- a/drivers/char/tpm/tpm-chip.c
> +++ b/drivers/char/tpm/tpm-chip.c
> @@ -543,6 +543,30 @@ static int tpm_get_pcr_allocation(struct tpm_chip *chip)
>  	return rc;
>  }
>  
> +/*
> + * tpm_chip_startup() - performs auto startup and allocates the PCRs
> + * @chip: TPM chip to use.
> + */
> +int tpm_chip_startup(struct tpm_chip *chip)
> +{
> +	int rc;
> +
> +	rc = tpm_chip_start(chip);
> +	if (rc)
> +		return rc;
> +
> +	rc = tpm_auto_startup(chip);
> +	if (rc)
> +		goto stop;
> +
> +	rc = tpm_get_pcr_allocation(chip);
> +stop:
> +	tpm_chip_stop(chip);
> +
> +	return rc;
> +}
> +EXPORT_SYMBOL_GPL(tpm_chip_startup);
> +
>  /*
>   * tpm_chip_register() - create a character device for the TPM chip
>   * @chip: TPM chip to use.
> @@ -558,20 +582,6 @@ int tpm_chip_register(struct tpm_chip *chip)
>  {
>  	int rc;
>  
> -	rc = tpm_chip_start(chip);
> -	if (rc)
> -		return rc;
> -	rc = tpm_auto_startup(chip);
> -	if (rc) {
> -		tpm_chip_stop(chip);
> -		return rc;
> -	}
> -
> -	rc = tpm_get_pcr_allocation(chip);
> -	tpm_chip_stop(chip);
> -	if (rc)
> -		return rc;
> -
>  	tpm_sysfs_add_device(chip);
>  
>  	tpm_bios_log_setup(chip);
> diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
> index 24ee4e1cc452..919bb0b88b12 100644
> --- a/drivers/char/tpm/tpm.h
> +++ b/drivers/char/tpm/tpm.h
> @@ -190,6 +190,7 @@ static inline void tpm_msleep(unsigned int delay_msec)
>  		     delay_msec * 1000);
>  };
>  
> +int tpm_chip_startup(struct tpm_chip *chip);
>  int tpm_chip_start(struct tpm_chip *chip);
>  void tpm_chip_stop(struct tpm_chip *chip);
>  struct tpm_chip *tpm_find_get_ops(struct tpm_chip *chip);
> diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
> index ddaf362e62c1..94a2bfb244b3 100644
> --- a/drivers/char/tpm/tpm_tis_core.c
> +++ b/drivers/char/tpm/tpm_tis_core.c
> @@ -1129,6 +1129,11 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq,
>  	/* INTERRUPT Setup */
>  	init_waitqueue_head(&priv->read_queue);
>  	init_waitqueue_head(&priv->int_queue);
> +
> +	rc = tpm_chip_startup(chip);
> +	if (rc)
> +		goto out_err;
> +
>  	if (irq != -1) {
>  		/*
>  		 * Before doing irq testing issue a command to the TPM in polling mode
> -- 
> 2.36.1
> 

Reviewed-by: Jarkko Sakkinen <jarkko@...nel.org>

BR, Jarkko