linux-kernel - Re: [PATCH v5 02/10] tpm, tpm_tis: Claim locality before writing TPM_INT

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Date:   Wed, 15 Jun 2022 17:33:16 +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 02/10] tpm, tpm_tis: Claim locality before writing
 TPM_INT_ENABLE register

On Fri, Jun 10, 2022 at 01:08:38PM +0200, LinoSanfilippo@....de wrote:
> From: Lino Sanfilippo <l.sanfilippo@...bus.com>
> 
> In disable_interrupts() the TPM_GLOBAL_INT_ENABLE bit is unset in the
> TPM_INT_ENABLE register to shut the interrupts off. However modifying the
> register is only possible with a held locality. So claim the locality
> before disable_interrupts() is called.
> 
> Signed-off-by: Lino Sanfilippo <l.sanfilippo@...bus.com>
> ---
>  drivers/char/tpm/tpm_tis_core.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
> index 6f2cf75add8b..ee6b48c55ac9 100644
> --- a/drivers/char/tpm/tpm_tis_core.c
> +++ b/drivers/char/tpm/tpm_tis_core.c
> @@ -1084,7 +1084,11 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq,
>  				dev_err(&chip->dev, FW_BUG
>  					"TPM interrupt not working, polling instead\n");
>  
> +				rc = request_locality(chip, 0);
> +				if (rc < 0)
> +					goto out_err;
>  				disable_interrupts(chip);
> +				release_locality(chip, 0);
>  			}
>  		} else {
>  			tpm_tis_probe_irq(chip, intmask);
> -- 
> 2.36.1
> 

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

BR, Jarkko