[PATCH] tpm: unify tpm_gen_interrupt() and fix error handling

From: Jarkko Sakkinen
Date: Thu Jun 16 2016 - 06:43:40 EST


Migrated into single tpm_gen_interrupt() function and cleaned up the
whole construction in general because it was starting to turn into a
train wreck.

Made the following updates:

* Use tpm_getcap() for TPM 1.x instead of creating an ad-hoc protocol
message.
* Return the error code back to the caller.
* Updated tpm_tis to fail in the case of a system error.

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
---
drivers/char/tpm/tpm-interface.c | 25 +++++++++++++++----------
drivers/char/tpm/tpm.h | 3 +--
drivers/char/tpm/tpm2-cmd.c | 17 -----------------
drivers/char/tpm/tpm_tis_core.c | 7 +++----
4 files changed, 19 insertions(+), 33 deletions(-)

diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index 5e3c1b6..4aeacf3 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -459,18 +459,23 @@ ssize_t tpm_getcap(struct tpm_chip *chip, __be32 subcap_id, cap_t *cap,
return rc;
}

-void tpm_gen_interrupt(struct tpm_chip *chip)
+/**
+ * tpm_gen_interrupt -- generate an interrupt by issuing an idempotent command
+ * @chip: TPM chip to use
+ *
+ * Returns 0 on success, < 0 in case of fatal error or a value > 0 representing
+ * a TPM error code.
+ */
+int tpm_gen_interrupt(struct tpm_chip *chip)
{
- struct tpm_cmd_t tpm_cmd;
- ssize_t rc;
+ const char *desc = "attempting to generate an interrupt";
+ u32 cap2;
+ cap_t cap;

- tpm_cmd.header.in = tpm_getcap_header;
- tpm_cmd.params.getcap_in.cap = TPM_CAP_PROP;
- tpm_cmd.params.getcap_in.subcap_size = cpu_to_be32(4);
- tpm_cmd.params.getcap_in.subcap = TPM_CAP_PROP_TIS_TIMEOUT;
-
- rc = tpm_transmit_cmd(chip, &tpm_cmd, TPM_INTERNAL_RESULT_SIZE,
- "attempting to determine the timeouts");
+ if (chip->flags & TPM_CHIP_FLAG_TPM2)
+ return tpm2_get_tpm_pt(chip, 0x100, &cap2, desc);
+ else
+ return tpm_getcap(chip, TPM_CAP_PROP_TIS_TIMEOUT, &cap, desc);
}
EXPORT_SYMBOL_GPL(tpm_gen_interrupt);

diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 8890df2..de93535 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -483,7 +483,7 @@ ssize_t tpm_transmit(struct tpm_chip *chip, const char *buf,
ssize_t tpm_transmit_cmd(struct tpm_chip *chip, void *cmd, int len,
const char *desc);
extern int tpm_get_timeouts(struct tpm_chip *);
-extern void tpm_gen_interrupt(struct tpm_chip *);
+int tpm_gen_interrupt(struct tpm_chip *);
extern int tpm_do_selftest(struct tpm_chip *);
extern unsigned long tpm_calc_ordinal_duration(struct tpm_chip *, u32);
extern int tpm_pm_suspend(struct device *);
@@ -530,6 +530,5 @@ extern int tpm2_startup(struct tpm_chip *chip, u16 startup_type);
extern void tpm2_shutdown(struct tpm_chip *chip, u16 shutdown_type);
extern unsigned long tpm2_calc_ordinal_duration(struct tpm_chip *, u32);
extern int tpm2_do_selftest(struct tpm_chip *chip);
-extern int tpm2_gen_interrupt(struct tpm_chip *chip);
extern int tpm2_probe(struct tpm_chip *chip);
#endif
diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index a1673dc..77ef027 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -897,23 +897,6 @@ int tpm2_do_selftest(struct tpm_chip *chip)
EXPORT_SYMBOL_GPL(tpm2_do_selftest);

/**
- * tpm2_gen_interrupt() - generate an interrupt
- * @chip: TPM chip to use
- *
- * 0 is returned when the operation is successful. If a negative number is
- * returned it remarks a POSIX error code. If a positive number is returned
- * it remarks a TPM error.
- */
-int tpm2_gen_interrupt(struct tpm_chip *chip)
-{
- u32 dummy;
-
- return tpm2_get_tpm_pt(chip, 0x100, &dummy,
- "attempting to generate an interrupt");
-}
-EXPORT_SYMBOL_GPL(tpm2_gen_interrupt);
-
-/**
* tpm2_probe() - probe TPM 2.0
* @chip: TPM chip to use
*
diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
index 03a06b3..79168ca 100644
--- a/drivers/char/tpm/tpm_tis_core.c
+++ b/drivers/char/tpm/tpm_tis_core.c
@@ -580,10 +580,9 @@ static int tpm_tis_probe_irq_single(struct tpm_chip *chip, u32 intmask,
/* Generate an interrupt by having the core call through to
* tpm_tis_send
*/
- if (chip->flags & TPM_CHIP_FLAG_TPM2)
- tpm2_gen_interrupt(chip);
- else
- tpm_gen_interrupt(chip);
+ rc = tpm_gen_interrupt(chip);
+ if (rc < 0)
+ return rc;

/* tpm_tis_send will either confirm the interrupt is working or it
* will call disable_irq which undoes all of the above.
--
2.7.4