[PATCH v13 16/19] tpm, tpm_tis: Allow locality to be set to a different value

[Ross Philipson]

DRTM needs to be able to set the locality used by kernel. Provide
a one-shot function tpm_chip_set_locality() for the purpose.

Signed-off-by: Ross Philipson <ross.philip...@oracle.com>
Signed-off-by: Jarkko Sakkinen <jar...@kernel.org>
---
 drivers/char/tpm/tpm-chip.c     | 33 ++++++++++++++++++++++++++++++++-
 drivers/char/tpm/tpm_tis_core.c |  2 ++
 include/linux/tpm.h             |  4 ++++
 3 files changed, 38 insertions(+), 1 deletion(-)

diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index 7df7abaf3e52..ac200514c4d7 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->kernel_locality);
        if (rc < 0)
                return rc;
 
@@ -374,6 +374,7 @@ struct tpm_chip *tpm_chip_alloc(struct device *pdev,
        }
 
        chip->locality = -1;
+       chip->kernel_locality = 0;
        return chip;
 
 out:
@@ -689,3 +690,33 @@ void tpm_chip_unregister(struct tpm_chip *chip)
        tpm_del_char_device(chip);
 }
 EXPORT_SYMBOL_GPL(tpm_chip_unregister);
+
+/**
+ * tpm_chip_set_locality() - Set the TPM locality kernel uses
+ * @chip:      &tpm_chip instance
+ * @locality:   new locality
+ *
+ * This a one-shot function. Returns zero or POSIX error on failure.
+ */
+int tpm_chip_set_locality(struct tpm_chip *chip, u8 locality)
+{
+       int ret;
+
+       if (locality < 0 || locality >= TPM_MAX_LOCALITY)
+               return -EINVAL;
+
+       ret = tpm_try_get_ops(chip);
+       if (ret)
+               return ret;
+
+       if (!(chip->flags & TPM_CHIP_FLAG_SET_LOCALITY_ENABLED)) {
+               tpm_put_ops(chip);
+               return -EINVAL;
+       }
+
+       chip->kernel_locality = locality;
+       chip->flags &= ~TPM_CHIP_FLAG_SET_LOCALITY_ENABLED;
+       tpm_put_ops(chip);
+       return 0;
+}
+EXPORT_SYMBOL_GPL(tpm_chip_set_locality);
diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
index f9a3489313b4..fd17cccb8abf 100644
--- a/drivers/char/tpm/tpm_tis_core.c
+++ b/drivers/char/tpm/tpm_tis_core.c
@@ -1117,6 +1117,8 @@ int tpm_tis_core_init(struct device *dev, struct 
tpm_tis_data *priv, int irq,
        if (IS_ERR(chip))
                return PTR_ERR(chip);
 
+       chip->flags |= TPM_CHIP_FLAG_SET_LOCALITY_ENABLED;
+
 #ifdef CONFIG_ACPI
        chip->acpi_dev_handle = acpi_dev_handle;
 #endif
diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index c5a4a2d7dd15..9f910d3bc2e4 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -207,6 +207,8 @@ struct tpm_chip {
 
        /* active locality */
        int locality;
+       /* the locality used by kernel */
+       u8 kernel_locality;
 
 #ifdef CONFIG_TCG_TPM2_HMAC
        /* details for communication security via sessions */
@@ -354,6 +356,7 @@ enum tpm_chip_flags {
        TPM_CHIP_FLAG_SUSPENDED                 = BIT(8),
        TPM_CHIP_FLAG_HWRNG_DISABLED            = BIT(9),
        TPM_CHIP_FLAG_DISABLE                   = BIT(10),
+       TPM_CHIP_FLAG_SET_LOCALITY_ENABLED      = BIT(11),
 };
 
 #define to_tpm_chip(d) container_of(d, struct tpm_chip, dev)
@@ -447,6 +450,7 @@ static inline u32 tpm2_rc_value(u32 rc)
 extern int tpm_is_tpm2(struct tpm_chip *chip);
 extern __must_check int tpm_try_get_ops(struct tpm_chip *chip);
 extern void tpm_put_ops(struct tpm_chip *chip);
+int tpm_chip_set_locality(struct tpm_chip *chip, u8 locality);
 extern ssize_t tpm_transmit_cmd(struct tpm_chip *chip, struct tpm_buf *buf,
                                size_t min_rsp_body_length, const char *desc);
 extern int tpm_pcr_read(struct tpm_chip *chip, u32 pcr_idx,
-- 
2.39.3