linux-kernel - Re: [PATCH 1/2] tpm_tis: Use tpm_chip_{start,stop} decoration inside tpm_tis

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Date:   Thu, 27 Apr 2023 08:11:40 -0700
From:   Jerry Snitselaar <jsnitsel@...hat.com>
To:     Jarkko Sakkinen <jarkko@...nel.org>
Cc:     linux-integrity@...r.kernel.org, linux-kernel@...r.kernel.org,
        Peter Huewe <peterhuewe@....de>,
        Jason Gunthorpe <jgg@...pe.ca>,
        Stefan Berger <stefanb@...ux.ibm.com>,
        James Bottomley <James.Bottomley@...senpartnership.com>,
        stable@...r.kernel.org, "Jason A . Donenfeld" <Jason@...c4.com>
Subject: Re: [PATCH 1/2] tpm_tis: Use tpm_chip_{start,stop} decoration inside
 tpm_tis_resume

On Wed, Apr 26, 2023 at 08:29:27PM +0300, Jarkko Sakkinen wrote:
> Before sending a TPM command, CLKRUN protocol must be disabled. This is not
> done in the case of tpm1_do_selftest() call site inside tpm_tis_resume().
> 
> Address this by decorating the calls with tpm_chip_{start,stop}, which arm
> and disarm the TPM chip for transmission, and take care of disabling and
> re-enabling CLKRUN, among other things.
> 
> Cc: stable@...r.kernel.org
> Reported-by: Jason A. Donenfeld <Jason@...c4.com>
> Link: https://lore.kernel.org/linux-integrity/CS68AWILHXS4.3M36M1EKZLUMS@suppilovahvero/
> Fixes: a3fbfae82b4c ("tpm: take TPM chip power gating out of tpm_transmit()")
> Signed-off-by: Jarkko Sakkinen <jarkko@...nel.org>
> ---
>  drivers/char/tpm/tpm_tis_core.c | 43 +++++++++++++++------------------
>  1 file changed, 19 insertions(+), 24 deletions(-)


Reviewed-by: Jerry Snitselaar <jsnitsel@...hat.com

> 
> diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
> index c2421162cf34..73707026e358 100644
> --- a/drivers/char/tpm/tpm_tis_core.c
> +++ b/drivers/char/tpm/tpm_tis_core.c
> @@ -1209,25 +1209,20 @@ static void tpm_tis_reenable_interrupts(struct tpm_chip *chip)
>  	u32 intmask;
>  	int rc;
>  
> -	if (chip->ops->clk_enable != NULL)
> -		chip->ops->clk_enable(chip, true);
> -
> -	/* reenable interrupts that device may have lost or
> -	 * BIOS/firmware may have disabled
> +	/*
> +	 * Re-enable interrupts that device may have lost or BIOS/firmware may
> +	 * have disabled.
>  	 */
>  	rc = tpm_tis_write8(priv, TPM_INT_VECTOR(priv->locality), priv->irq);
> -	if (rc < 0)
> -		goto out;
> +	if (rc < 0) {
> +		dev_err(&chip->dev, "Setting IRQ failed.\n");
> +		return;
> +	}
>  
>  	intmask = priv->int_mask | TPM_GLOBAL_INT_ENABLE;
> -
> -	tpm_tis_write32(priv, TPM_INT_ENABLE(priv->locality), intmask);
> -
> -out:
> -	if (chip->ops->clk_enable != NULL)
> -		chip->ops->clk_enable(chip, false);
> -
> -	return;
> +	rc = tpm_tis_write32(priv, TPM_INT_ENABLE(priv->locality), intmask);
> +	if (rc < 0)
> +		dev_err(&chip->dev, "Enabling interrupts failed.\n");
>  }
>  
>  int tpm_tis_resume(struct device *dev)
> @@ -1235,27 +1230,27 @@ int tpm_tis_resume(struct device *dev)
>  	struct tpm_chip *chip = dev_get_drvdata(dev);
>  	int ret;
>  
> -	ret = tpm_tis_request_locality(chip, 0);
> -	if (ret < 0)
> +	ret = tpm_chip_start(chip);
> +	if (ret)
>  		return ret;
>  
>  	if (chip->flags & TPM_CHIP_FLAG_IRQ)
>  		tpm_tis_reenable_interrupts(chip);
>  
> -	ret = tpm_pm_resume(dev);
> -	if (ret)
> -		goto out;
> -
>  	/*
>  	 * TPM 1.2 requires self-test on resume. This function actually returns
>  	 * an error code but for unknown reason it isn't handled.
>  	 */
>  	if (!(chip->flags & TPM_CHIP_FLAG_TPM2))
>  		tpm1_do_selftest(chip);
> -out:
> -	tpm_tis_relinquish_locality(chip, 0);
>  
> -	return ret;
> +	tpm_chip_stop(chip);
> +
> +	ret = tpm_pm_resume(dev);
> +	if (ret)
> +		return ret;
> +
> +	return 0;
>  }
>  EXPORT_SYMBOL_GPL(tpm_tis_resume);
>  #endif
> -- 
> 2.39.2
>