Re: [PATCH v2 2/2] tpm: Disable TPM on TPM_RC_INITIALIZE

[Jarkko Sakkinen <jarkko@kernel.org>]

On Thu, Nov 12, 2026 at 04:30:18AM -0800, Breno Leitao wrote:
> From: Jarkko Sakkinen <jarkko@kernel.org>
> 
> If the TPM has been spuriously disabled, the game is over. Let's reflect
> this truth with TPM_CHIP_FLAG_DISABLE.
> 
> Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
> [leitao@debian.org: check rc before the loop breaks out on anything but
>  RETRY/TESTING, skip TPM2_Startup, which a TPM that is already started
>  fails with TPM2_RC_INITIALIZE, and fix the TPM2_RC_INITIALIZE and
>  chip->flags typos]
> Signed-off-by: Breno Leitao <leitao@debian.org>
> ---
>  drivers/char/tpm/tpm-interface.c | 5 +++++
>  drivers/char/tpm/tpm2-cmd.c      | 2 ++
>  2 files changed, 7 insertions(+)
> 
> diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
> index b7865ccb799289..144e2dbae66853 100644
> --- a/drivers/char/tpm/tpm-interface.c
> +++ b/drivers/char/tpm/tpm-interface.c
> @@ -252,6 +252,11 @@ ssize_t tpm_transmit(struct tpm_chip *chip, u8 *buf, size_t bufsiz)
>  		if (ret < 0)
>  			break;
>  		rc = be32_to_cpu(header->return_code);
> +		/* A TPM that is already started fails TPM2_Startup this way. */
> +		if (rc == TPM2_RC_INITIALIZE && cc != TPM2_CC_STARTUP) {

Good catch! Thanks.

> +			chip->flags |= TPM_CHIP_FLAG_DISABLE;
> +			break;
> +		}
>  		if (rc != TPM2_RC_RETRY && rc != TPM2_RC_TESTING)
>  			break;
>  		/*
> diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
> index 4b2bb2ddc321a9..65928ae85b496c 100644
> --- a/drivers/char/tpm/tpm2-cmd.c
> +++ b/drivers/char/tpm/tpm2-cmd.c
> @@ -724,6 +724,8 @@ int tpm2_auto_startup(struct tpm_chip *chip)
>  		goto out;
>  
>  	if (rc == TPM2_RC_INITIALIZE) {
> +		chip->flags &= ~TPM_CHIP_FLAG_DISABLE;
> +
>  		rc = tpm2_startup(chip);
>  		if (rc)
>  			goto out;
> 
> -- 
> 2.53.0-Meta
> 

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

Br, Jarkko