[PATCH v14 2/7] tpm: tpm_tis: Fix expected bit handling and send all bytes in one shot without last byte in exception
From: amirmizi6
Date: Mon Sep 13 2021 - 10:52:10 EST
From: Amir Mizinski <amirmizi6@xxxxxxxxx>
Detected an incorrect implementation of the send command.
Currently, the driver polls the TPM_STS.stsValid field until TRUE; then it
reads TPM_STS register again to verify only that TPM_STS.expect field is
FALSE (i.e., it ignores TPM_STS.stsValid).
Since TPM_STS.stsValid represents the TPM_STS.expect validity, both fields
fields should be checked in the same TPM_STS register read value.
This fix modifies the signature of 'wait_for_tpm_stat()', adding an
additional "mask_result" parameter to its call and renaming it to
'tpm_tis_wait_for_stat()' for better alignment with other naming.
'tpm_tis_wait_for_stat()' is now polling the TPM_STS with a mask and waits
for the value in mask_result. The fix adds the ability to check if certain
TPM_STS bits have been cleared.
This change is also aligned to verifying the CRC on I2C TPM. The CRC
verification should be done after the TPM_STS.expect field is cleared
(TPM received all expected command bytes and set the calculated CRC value
in the register).
In addition, the send command was changed to comply with
TCG_DesignPrinciples_TPM2p0Driver_vp24_pubrev.pdf as follows:
- send all command bytes in one loop
- remove special handling of the last byte
Suggested-by: Benoit Houyere <benoit.houyere@xxxxxx>
Signed-off-by: Amir Mizinski <amirmizi6@xxxxxxxxx>
---
drivers/char/tpm/tpm_tis_core.c | 70 +++++++++++++++--------------------------
1 file changed, 26 insertions(+), 44 deletions(-)
diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
index 69579ef..b34e59b 100644
--- a/drivers/char/tpm/tpm_tis_core.c
+++ b/drivers/char/tpm/tpm_tis_core.c
@@ -44,9 +44,9 @@ static bool wait_for_tpm_stat_cond(struct tpm_chip *chip, u8 mask,
return false;
}
-static int wait_for_tpm_stat(struct tpm_chip *chip, u8 mask,
- unsigned long timeout, wait_queue_head_t *queue,
- bool check_cancel)
+static int tpm_tis_wait_for_stat(struct tpm_chip *chip, u8 mask, u8 stat,
+ unsigned long timeout,
+ wait_queue_head_t *queue, bool check_cancel)
{
unsigned long stop;
long rc;
@@ -55,7 +55,7 @@ static int wait_for_tpm_stat(struct tpm_chip *chip, u8 mask,
/* check current status */
status = chip->ops->status(chip);
- if ((status & mask) == mask)
+ if ((status & mask) == stat)
return 0;
stop = jiffies + timeout;
@@ -83,7 +83,7 @@ static int wait_for_tpm_stat(struct tpm_chip *chip, u8 mask,
usleep_range(TPM_TIMEOUT_USECS_MIN,
TPM_TIMEOUT_USECS_MAX);
status = chip->ops->status(chip);
- if ((status & mask) == mask)
+ if ((status & mask) == stat)
return 0;
} while (time_before(jiffies, stop));
}
@@ -259,10 +259,11 @@ static int recv_data(struct tpm_chip *chip, u8 *buf, size_t count)
int size = 0, burstcnt, rc;
while (size < count) {
- rc = wait_for_tpm_stat(chip,
- TPM_STS_DATA_AVAIL | TPM_STS_VALID,
- chip->timeout_c,
- &priv->read_queue, true);
+ rc = tpm_tis_wait_for_stat(chip,
+ TPM_STS_DATA_AVAIL | TPM_STS_VALID,
+ TPM_STS_DATA_AVAIL | TPM_STS_VALID,
+ chip->timeout_c, &priv->read_queue,
+ true);
if (rc < 0)
return rc;
burstcnt = get_burstcount(chip);
@@ -315,8 +316,9 @@ static int tpm_tis_recv(struct tpm_chip *chip, u8 *buf, size_t count)
goto out;
}
- if (wait_for_tpm_stat(chip, TPM_STS_VALID, chip->timeout_c,
- &priv->int_queue, false) < 0) {
+ if (tpm_tis_wait_for_stat(chip, TPM_STS_VALID, TPM_STS_VALID,
+ chip->timeout_c, &priv->int_queue,
+ false) < 0) {
size = -ETIME;
goto out;
}
@@ -342,61 +344,40 @@ static int tpm_tis_send_data(struct tpm_chip *chip, const u8 *buf, size_t len)
struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
int rc, status, burstcnt;
size_t count = 0;
- bool itpm = priv->flags & TPM_TIS_ITPM_WORKAROUND;
status = tpm_tis_status(chip);
if ((status & TPM_STS_COMMAND_READY) == 0) {
tpm_tis_ready(chip);
- if (wait_for_tpm_stat
- (chip, TPM_STS_COMMAND_READY, chip->timeout_b,
- &priv->int_queue, false) < 0) {
+ if (tpm_tis_wait_for_stat(chip, TPM_STS_COMMAND_READY,
+ TPM_STS_COMMAND_READY,
+ chip->timeout_b, &priv->int_queue,
+ false) < 0) {
rc = -ETIME;
goto out_err;
}
}
- while (count < len - 1) {
+ while (count < len) {
burstcnt = get_burstcount(chip);
if (burstcnt < 0) {
dev_err(&chip->dev, "Unable to read burstcount\n");
rc = burstcnt;
goto out_err;
}
- burstcnt = min_t(int, burstcnt, len - count - 1);
+ burstcnt = min_t(int, burstcnt, len - count);
rc = tpm_tis_write_bytes(priv, TPM_DATA_FIFO(priv->locality),
burstcnt, buf + count);
if (rc < 0)
goto out_err;
count += burstcnt;
-
- if (wait_for_tpm_stat(chip, TPM_STS_VALID, chip->timeout_c,
- &priv->int_queue, false) < 0) {
- rc = -ETIME;
- goto out_err;
- }
- status = tpm_tis_status(chip);
- if (!itpm && (status & TPM_STS_DATA_EXPECT) == 0) {
- rc = -EIO;
- goto out_err;
- }
}
-
- /* write last byte */
- rc = tpm_tis_write8(priv, TPM_DATA_FIFO(priv->locality), buf[count]);
- if (rc < 0)
- goto out_err;
-
- if (wait_for_tpm_stat(chip, TPM_STS_VALID, chip->timeout_c,
- &priv->int_queue, false) < 0) {
+ if (tpm_tis_wait_for_stat(chip, TPM_STS_VALID | TPM_STS_DATA_EXPECT,
+ TPM_STS_VALID, chip->timeout_a,
+ &priv->int_queue, false) < 0) {
rc = -ETIME;
goto out_err;
}
- status = tpm_tis_status(chip);
- if (!itpm && (status & TPM_STS_DATA_EXPECT) != 0) {
- rc = -EIO;
- goto out_err;
- }
return 0;
@@ -451,9 +432,10 @@ static int tpm_tis_send_main(struct tpm_chip *chip, const u8 *buf, size_t len)
ordinal = be32_to_cpu(*((__be32 *) (buf + 6)));
dur = tpm_calc_ordinal_duration(chip, ordinal);
- if (wait_for_tpm_stat
- (chip, TPM_STS_DATA_AVAIL | TPM_STS_VALID, dur,
- &priv->read_queue, false) < 0) {
+ if (tpm_tis_wait_for_stat(chip,
+ TPM_STS_DATA_AVAIL | TPM_STS_VALID,
+ TPM_STS_DATA_AVAIL | TPM_STS_VALID,
+ dur, &priv->read_queue, false) < 0) {
rc = -ETIME;
goto out_err;
}
--
2.7.4