linux-kernel - Re: [PATCH v11 04/14] tpm, tpm_tis: Do not skip reset of original interrupt vector

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Date:   Mon, 28 Nov 2022 03:26:12 +0200
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 04/14] tpm, tpm_tis: Do not skip reset of original
 interrupt vector

On Thu, Nov 24, 2022 at 02:55:28PM +0100, Lino Sanfilippo wrote:
> From: Lino Sanfilippo <l.sanfilippo@...bus.com>
> 
> If in tpm_tis_probe_irq_single() an error occurs after the original
> interrupt vector has been read, restore the interrupts before the error is
> returned.
> 
> Since the caller does not check the error value, return -1 in any case that
> the TPM_CHIP_FLAG_IRQ flag is not set. Since the return value of function
> tpm_tis_gen_interrupt() is not longer used, make it a void function.
> 
> Fixes: 1107d065fdf1 ("tpm_tis: Introduce intermediate layer for TPM access")
> Signed-off-by: Lino Sanfilippo <l.sanfilippo@...bus.com>
> ---
>  drivers/char/tpm/tpm_tis_core.c | 29 +++++++++++------------------
>  1 file changed, 11 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
> index 603b82ca56da..81b9726d3ed2 100644
> --- a/drivers/char/tpm/tpm_tis_core.c
> +++ b/drivers/char/tpm/tpm_tis_core.c
> @@ -729,7 +729,7 @@ static irqreturn_t tis_int_handler(int dummy, void *dev_id)
>  	return IRQ_HANDLED;
>  }
>  
> -static int tpm_tis_gen_interrupt(struct tpm_chip *chip)
> +static void tpm_tis_gen_interrupt(struct tpm_chip *chip)
>  {
>  	const char *desc = "attempting to generate an interrupt";
>  	u32 cap2;
> @@ -738,7 +738,7 @@ static int tpm_tis_gen_interrupt(struct tpm_chip *chip)
>  
>  	ret = request_locality(chip, 0);
>  	if (ret < 0)
> -		return ret;
> +		return;
>  
>  	if (chip->flags & TPM_CHIP_FLAG_TPM2)
>  		ret = tpm2_get_tpm_pt(chip, 0x100, &cap2, desc);
> @@ -746,8 +746,6 @@ static int tpm_tis_gen_interrupt(struct tpm_chip *chip)
>  		ret = tpm1_getcap(chip, TPM_CAP_PROP_TIS_TIMEOUT, &cap, desc, 0);
>  
>  	release_locality(chip, 0);
> -
> -	return ret;
>  }
>  
>  /* Register the IRQ and issue a command that will cause an interrupt. If an
> @@ -777,42 +775,37 @@ static int tpm_tis_probe_irq_single(struct tpm_chip *chip, u32 intmask,
>  
>  	rc = tpm_tis_write8(priv, TPM_INT_VECTOR(priv->locality), irq);
>  	if (rc < 0)
> -		return rc;
> +		goto restore_irqs;
>  
>  	rc = tpm_tis_read32(priv, TPM_INT_STATUS(priv->locality), &int_status);
>  	if (rc < 0)
> -		return rc;
> +		goto restore_irqs;
>  
>  	/* Clear all existing */
>  	rc = tpm_tis_write32(priv, TPM_INT_STATUS(priv->locality), int_status);
>  	if (rc < 0)
> -		return rc;
> -
> +		goto restore_irqs;
>  	/* Turn on */
>  	rc = tpm_tis_write32(priv, TPM_INT_ENABLE(priv->locality),
>  			     intmask | TPM_GLOBAL_INT_ENABLE);
>  	if (rc < 0)
> -		return rc;
> +		goto restore_irqs;
>  
>  	clear_bit(TPM_TIS_IRQ_TESTED, &priv->flags);
>  
>  	/* Generate an interrupt by having the core call through to
>  	 * tpm_tis_send
>  	 */
> -	rc = tpm_tis_gen_interrupt(chip);
> -	if (rc < 0)
> -		return rc;
> +	tpm_tis_gen_interrupt(chip);
>  
> +restore_irqs:
>  	/* tpm_tis_send will either confirm the interrupt is working or it
>  	 * will call disable_irq which undoes all of the above.
>  	 */
>  	if (!(chip->flags & TPM_CHIP_FLAG_IRQ)) {
> -		rc = tpm_tis_write8(priv, original_int_vec,
> -				TPM_INT_VECTOR(priv->locality));
> -		if (rc < 0)
> -			return rc;
> -
> -		return 1;
> +		tpm_tis_write8(priv, original_int_vec,
> +			       TPM_INT_VECTOR(priv->locality));
> +		return -1;
>  	}
>  
>  	return 0;
> -- 
> 2.36.1
> 

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

BR, Jarkko