linux-kernel - Re: [PATCH v5 09/10] tpm, tpm_tis: Claim locality in interrupt handler

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Date:   Wed, 15 Jun 2022 21:25:24 +0300
From:   Jarkko Sakkinen <jarkko@...nel.org>
To:     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, l.sanfilippo@...bus.com,
        lukas@...ner.de, p.rosenberger@...bus.com
Subject: Re: [PATCH v5 09/10] tpm, tpm_tis: Claim locality in interrupt
 handler

On Fri, Jun 10, 2022 at 01:08:45PM +0200, LinoSanfilippo@....de wrote:
> From: Lino Sanfilippo <l.sanfilippo@...bus.com>
> 
> Writing the TPM_INT_STATUS register in the interrupt handler to clear the
> interrupts only has effect if a locality is held. Since this is not
> guaranteed at the time the interrupt is fired, claim the locality
> explicitly in the handler.
> 
> Signed-off-by: Lino Sanfilippo <l.sanfilippo@...bus.com>
> ---
>  drivers/char/tpm/tpm_tis_core.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
> index 8b5aa4fdbe92..e5edf745fb23 100644
> --- a/drivers/char/tpm/tpm_tis_core.c
> +++ b/drivers/char/tpm/tpm_tis_core.c
> @@ -753,7 +753,9 @@ static irqreturn_t tis_int_handler(int dummy, void *dev_id)
>  		wake_up_interruptible(&priv->int_queue);
>  
>  	/* Clear interrupts handled with TPM_EOI */
> +	request_locality(chip, 0);
>  	rc = tpm_tis_write32(priv, TPM_INT_STATUS(priv->locality), interrupt);
> +	release_locality(chip, 0);
>  	if (rc < 0)
>  		return IRQ_NONE;
>  
> -- 
> 2.36.1
> 

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

BR, Jarkko