[PATCH v9 16/19] tpm: Add ability to set the preferred locality the TPM chip uses

Ross Philipson
2024-05-31T01:33:21Z

Curently the locality is hard coded to 0 but for DRTM support, access
is needed to localities 1 through 4.

Signed-off-by: Ross Philipson <ross.philipson@oracle.com>
---
drivers/char/tpm/tpm-chip.c | 24 +++++++++++++++++++++++-
drivers/char/tpm/tpm-interface.c | 15 +++++++++++++++
drivers/char/tpm/tpm.h | 1 +
include/linux/tpm.h | 4 ++++
4 files changed, 43 insertions(+), 1 deletion(-)

diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index 854546000c92..73eac54d61fb 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -44,7 +44,7 @@ static int tpm_request_locality(struct tpm_chip *chip)
if (!chip->ops->request_locality)
return 0;

- rc = chip->ops->request_locality(chip, 0);
+ rc = chip->ops->request_locality(chip, chip->pref_locality);
if (rc < 0)
return rc;

@@ -143,6 +143,27 @@ void tpm_chip_stop(struct tpm_chip *chip)
}
EXPORT_SYMBOL_GPL(tpm_chip_stop);

+/**
+ * tpm_chip_preferred_locality() - set the TPM chip preferred locality to open
+ * @chip: a TPM chip to use
+ * @locality: the preferred locality
+ *
+ * Return:
+ * * true - Preferred locality set
+ * * false - Invalid locality specified
+ */
+bool tpm_chip_preferred_locality(struct tpm_chip *chip, int locality)
+{
+ if (locality < 0 || locality >=TPM_MAX_LOCALITY)
+ return false;
+
+ mutex_lock(&chip->tpm_mutex);
+ chip->pref_locality = locality;
+ mutex_unlock(&chip->tpm_mutex);
+ return true;
+}
+EXPORT_SYMBOL_GPL(tpm_chip_preferred_locality);
+
/**
* tpm_try_get_ops() - Get a ref to the tpm_chip
* @chip: Chip to ref
@@ -374,6 +395,7 @@ struct tpm_chip *tpm_chip_alloc(struct device *pdev,
}

chip->locality = -1;
+ chip->pref_locality = 0;
return chip;

out:
diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index 5da134f12c9a..35f14ccecf0e 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -274,6 +274,21 @@ int tpm_is_tpm2(struct tpm_chip *chip)
}
EXPORT_SYMBOL_GPL(tpm_is_tpm2);

+/**
+ * tpm_preferred_locality() - set the TPM chip preferred locality to open
+ * @chip: a TPM chip to use
+ * @locality: the preferred locality
+ *
+ * Return:
+ * * true - Preferred locality set
+ * * false - Invalid locality specified
+ */
+bool tpm_preferred_locality(struct tpm_chip *chip, int locality)
+{
+ return tpm_chip_preferred_locality(chip, locality);
+}
+EXPORT_SYMBOL_GPL(tpm_preferred_locality);
+
/**
* tpm_pcr_read - read a PCR value from SHA1 bank
* @chip: a &struct tpm_chip instance, %NULL for the default chip
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 6b8b9956ba69..be465422d3fa 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -267,6 +267,7 @@ static inline void tpm_msleep(unsigned int delay_msec)
int tpm_chip_bootstrap(struct tpm_chip *chip);
int tpm_chip_start(struct tpm_chip *chip);
void tpm_chip_stop(struct tpm_chip *chip);
+bool tpm_chip_preferred_locality(struct tpm_chip *chip, int locality);
struct tpm_chip *tpm_find_get_ops(struct tpm_chip *chip);

struct tpm_chip *tpm_chip_alloc(struct device *dev,
diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index 363f7078c3a9..935a3457d7c8 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -219,6 +219,9 @@ struct tpm_chip {
u8 null_ec_key_y[EC_PT_SZ];
struct tpm2_auth *auth;
#endif
+
+ /* preferred locality - default 0 */
+ int pref_locality;
};

#define TPM_HEADER_SIZE 10
@@ -461,6 +464,7 @@ static inline u32 tpm2_rc_value(u32 rc)
#if defined(CONFIG_TCG_TPM) || defined(CONFIG_TCG_TPM_MODULE)

extern int tpm_is_tpm2(struct tpm_chip *chip);
+extern bool tpm_preferred_locality(struct tpm_chip *chip, int locality);
extern __must_check int tpm_try_get_ops(struct tpm_chip *chip);
extern void tpm_put_ops(struct tpm_chip *chip);
extern ssize_t tpm_transmit_cmd(struct tpm_chip *chip, struct tpm_buf *buf,
--
2.39.3