Re: [PATCH v9 14/19] tpm: Ensure tpm is in known state at startup

Jarkko Sakkinen
2024-06-04T20:14:55Z

On Fri May 31, 2024 at 4:03 AM EEST, Ross Philipson wrote:
> From: "Daniel P. Smith" <dpsmith@apertussolutions.com>
>
> When tis core initializes, it assumes all localities are closed. There

s/tis_core/tpm_tis_core/

> are cases when this may not be the case. This commit addresses this by
> ensuring all localities are closed before initializing begins.
>
> Signed-off-by: Daniel P. Smith <dpsmith@apertussolutions.com>
> Signed-off-by: Ross Philipson <ross.philipson@oracle.com>
> ---
> drivers/char/tpm/tpm_tis_core.c | 11 ++++++++++-
> include/linux/tpm.h | 6 ++++++
> 2 files changed, 16 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
> index 7c1761bd6000..9fb53bb3e73f 100644
> --- a/drivers/char/tpm/tpm_tis_core.c
> +++ b/drivers/char/tpm/tpm_tis_core.c
> @@ -1104,7 +1104,7 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq,
> u32 intmask;
> u32 clkrun_val;
> u8 rid;
> - int rc, probe;
> + int rc, probe, i;
> struct tpm_chip *chip;
>
> chip = tpmm_chip_alloc(dev, &tpm_tis);
> @@ -1166,6 +1166,15 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq,
> goto out_err;
> }
>
> + /*
> + * There are environments, like Intel TXT, that may leave a TPM

What else at this point than Intel TXT reflecting the state of the
mainline?

> + * locality open. Close all localities to start from a known state.
> + */
> + for (i = 0; i <= TPM_MAX_LOCALITY; i++) {
> + if (check_locality(chip, i))
> + tpm_tis_relinquish_locality(chip, i);
> + }

To be strict this should be enabled only for x86 platforms.

I.e. should be flagged.

> +
> /* Take control of the TPM's interrupt hardware and shut it off */
> rc = tpm_tis_read32(priv, TPM_INT_ENABLE(priv->locality), &intmask);
> if (rc < 0)
> diff --git a/include/linux/tpm.h b/include/linux/tpm.h
> index c17e4efbb2e5..363f7078c3a9 100644
> --- a/include/linux/tpm.h
> +++ b/include/linux/tpm.h
> @@ -147,6 +147,12 @@ struct tpm_chip_seqops {
> */
> #define TPM2_MAX_CONTEXT_SIZE 4096
>
> +/*
> + * The maximum locality (0 - 4) for a TPM, as defined in section 3.2 of the
> + * Client Platform Profile Specification.
> + */
> +#define TPM_MAX_LOCALITY 4
> +
> struct tpm_chip {
> struct device dev;
> struct device devs;

BR, Jarkko