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 17:02:44 +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 Mon, Nov 28, 2022 at 01:53:35PM +0100, Lino Sanfilippo wrote:
> 
> On 24.11.22 14:55, 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
> 
> Jarko, thanks for the review so far. What about this patch, are there any concerns from your side?

No concerns on this one.

BR, Jarkko