Re: [PATCH v9 4/5] tpm: Allow TPM chip drivers to override reported command durations

From: Jarkko Sakkinen
Date: Mon Jul 18 2016 - 14:40:17 EST

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On Wed, Jul 13, 2016 at 09:19:35AM -0700, Ed Swierk wrote:
> Some TPM chips report bogus command durations in their capabilities,
> just as others report incorrect timeouts. Rework tpm_get_timeouts() to
> allow chip drivers to override either via a single callback. Also
> clean up handling of TPMs that report milliseconds instead of
> microseconds.

I don't really undestand why you need to turn things so much over.
There's too much noise in this commit to reasonably evaluate it.

> Signed-off-by: Ed Swierk <eswierk@xxxxxxxxxxxxxxxxxx>
> ---
> drivers/char/tpm/tpm-interface.c | 148 ++++++++++++++++++++++-----------------
> drivers/char/tpm/tpm_tis_core.c | 32 +++------
> include/linux/tpm.h | 3 +-
> 3 files changed, 94 insertions(+), 89 deletions(-)
>
> diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
> index dc492ee..9dafc25 100644
> --- a/drivers/char/tpm/tpm-interface.c
> +++ b/drivers/char/tpm/tpm-interface.c
> @@ -513,10 +513,10 @@ static int tpm_startup(struct tpm_chip *chip, __be16 startup_type)
>
> int tpm_get_timeouts(struct tpm_chip *chip)
> {
> - cap_t cap;

cap_t cap2;

> - unsigned long new_timeout[4];
> - unsigned long old_timeout[4];
> - ssize_t rc;
> + cap_t cap1, cap2;

Do not use cap1.

> + int rc;
> + unsigned long orig_timeout_a, orig_timeout_b, orig_timeout_c,
> + orig_timeout_d, orig_duration[3];

Use old_timeout array just to reduce the diff.

>
> if (chip->flags & TPM_CHIP_FLAG_TPM2) {
> /* Fixed timeouts for TPM2 */
> @@ -533,7 +533,7 @@ int tpm_get_timeouts(struct tpm_chip *chip)
> return 0;
> }
>
> - rc = tpm_getcap(chip, TPM_CAP_PROP_TIS_TIMEOUT, &cap,
> + rc = tpm_getcap(chip, TPM_CAP_PROP_TIS_TIMEOUT, &cap1,
> "attempting to determine the timeouts");
> if (rc == TPM_ERR_INVALID_POSTINIT) {
> /* The TPM is not started, we are the first to talk to it.
> @@ -542,77 +542,95 @@ int tpm_get_timeouts(struct tpm_chip *chip)
> if (tpm_startup(chip, TPM_ST_CLEAR))
> return rc;
>
> - rc = tpm_getcap(chip, TPM_CAP_PROP_TIS_TIMEOUT, &cap,
> + rc = tpm_getcap(chip, TPM_CAP_PROP_TIS_TIMEOUT, &cap1,
> "attempting to determine the timeouts");
> }
> if (rc)
> return rc;
>
> - old_timeout[0] = be32_to_cpu(cap.timeout.a);
> - old_timeout[1] = be32_to_cpu(cap.timeout.b);
> - old_timeout[2] = be32_to_cpu(cap.timeout.c);
> - old_timeout[3] = be32_to_cpu(cap.timeout.d);
> - memcpy(new_timeout, old_timeout, sizeof(new_timeout));
> -
> - /*
> - * Provide ability for vendor overrides of timeout values in case
> - * of misreporting.
> - */
> - if (chip->ops->update_timeouts != NULL)
> - chip->timeout_adjusted =
> - chip->ops->update_timeouts(chip, new_timeout);
> -
> - if (!chip->timeout_adjusted) {
> - /* Don't overwrite default if value is 0 */
> - if (new_timeout[0] != 0 && new_timeout[0] < 1000) {
> - int i;
> -
> - /* timeouts in msec rather usec */
> - for (i = 0; i != ARRAY_SIZE(new_timeout); i++)
> - new_timeout[i] *= 1000;
> - chip->timeout_adjusted = true;
> - }
> - }
> -
> - /* Report adjusted timeouts */
> - if (chip->timeout_adjusted) {
> - dev_info(&chip->dev,
> - HW_ERR "Adjusting reported timeouts: A %lu->%luus B %lu->%luus C %lu->%luus D %lu->%luus\n",
> - old_timeout[0], new_timeout[0],
> - old_timeout[1], new_timeout[1],
> - old_timeout[2], new_timeout[2],
> - old_timeout[3], new_timeout[3]);
> - }
> -
> - chip->timeout_a = usecs_to_jiffies(new_timeout[0]);
> - chip->timeout_b = usecs_to_jiffies(new_timeout[1]);
> - chip->timeout_c = usecs_to_jiffies(new_timeout[2]);
> - chip->timeout_d = usecs_to_jiffies(new_timeout[3]);
> -
> - rc = tpm_getcap(chip, TPM_CAP_PROP_TIS_DURATION, &cap,
> + rc = tpm_getcap(chip, TPM_CAP_PROP_TIS_DURATION, &cap2,
> "attempting to determine the durations");
> if (rc)
> return rc;
>
> - chip->duration[TPM_SHORT] =
> - usecs_to_jiffies(be32_to_cpu(cap.duration.tpm_short));
> - chip->duration[TPM_MEDIUM] =
> - usecs_to_jiffies(be32_to_cpu(cap.duration.tpm_medium));
> - chip->duration[TPM_LONG] =
> - usecs_to_jiffies(be32_to_cpu(cap.duration.tpm_long));
> + be32_to_cpus(&cap1.timeout.a);
> + be32_to_cpus(&cap1.timeout.b);
> + be32_to_cpus(&cap1.timeout.c);
> + be32_to_cpus(&cap1.timeout.d);
> + chip->timeout_a = usecs_to_jiffies(cap1.timeout.a);
> + chip->timeout_b = usecs_to_jiffies(cap1.timeout.b);
> + chip->timeout_c = usecs_to_jiffies(cap1.timeout.c);
> + chip->timeout_d = usecs_to_jiffies(cap1.timeout.d);
>
> - /* The Broadcom BCM0102 chipset in a Dell Latitude D820 gets the above
> - * value wrong and apparently reports msecs rather than usecs. So we
> - * fix up the resulting too-small TPM_SHORT value to make things work.
> - * We also scale the TPM_MEDIUM and -_LONG values by 1000.
> - */
> - if (chip->duration[TPM_SHORT] < (HZ / 100)) {
> - chip->duration[TPM_SHORT] = HZ;
> - chip->duration[TPM_MEDIUM] *= 1000;
> - chip->duration[TPM_LONG] *= 1000;
> - chip->duration_adjusted = true;
> - dev_info(&chip->dev, "Adjusting TPM timeout parameters.");
> + /* Some TPMs report timeouts in milliseconds rather than
> + microseconds. Use a value between 1 and 1000 as an
> + indication that this is the case. */
> + if (cap1.timeout.a > 0 && cap1.timeout.a < 1000) {
> + chip->timeout_a = msecs_to_jiffies(cap1.timeout.a);
> + chip->timeout_b = msecs_to_jiffies(cap1.timeout.b);
> + chip->timeout_c = msecs_to_jiffies(cap1.timeout.c);
> + chip->timeout_d = msecs_to_jiffies(cap1.timeout.d);
> + chip->timeout_adjusted = true;
> }
> +
> + be32_to_cpus(&cap2.duration.tpm_short);
> + be32_to_cpus(&cap2.duration.tpm_medium);
> + be32_to_cpus(&cap2.duration.tpm_long);
> + chip->duration[TPM_SHORT] =
> + usecs_to_jiffies(cap2.duration.tpm_short);
> + chip->duration[TPM_MEDIUM] =
> + usecs_to_jiffies(cap2.duration.tpm_medium);
> + chip->duration[TPM_LONG] =
> + usecs_to_jiffies(cap2.duration.tpm_long);
> +
> + orig_timeout_a = chip->timeout_a;
> + orig_timeout_b = chip->timeout_b;
> + orig_timeout_c = chip->timeout_c;
> + orig_timeout_d = chip->timeout_d;
> + memcpy(orig_duration, chip->duration, 3 * sizeof(unsigned long));
> +
> + /* Interpret duration values between 1 and 10000 as
> + milliseconds to deal with TPMs like the Broadcom BCM0102 in
> + the Dell Latitude D820. */
> + if (cap2.duration.tpm_short > 0 && cap2.duration.tpm_short < 10000) {
> + chip->duration[TPM_SHORT] =
> + msecs_to_jiffies(cap2.duration.tpm_short);
> + chip->duration[TPM_MEDIUM] =
> + msecs_to_jiffies(cap2.duration.tpm_medium);
> + chip->duration[TPM_LONG] =
> + msecs_to_jiffies(cap2.duration.tpm_long);
> + chip->duration_adjusted = true;
> + }
> +
> + if (chip->ops->update_timeouts != NULL)
> + chip->ops->update_timeouts(chip);
> +
> + if (chip->timeout_adjusted) {
> + dev_info(&chip->dev,
> + HW_ERR "Adjusted timeouts: A %u->%uus B %u->%uus"
> + " C %u->%uus D %u->%uus\n",
> + jiffies_to_usecs(orig_timeout_a),
> + jiffies_to_usecs(chip->timeout_a),
> + jiffies_to_usecs(orig_timeout_b),
> + jiffies_to_usecs(chip->timeout_b),
> + jiffies_to_usecs(orig_timeout_c),
> + jiffies_to_usecs(chip->timeout_c),
> + jiffies_to_usecs(orig_timeout_d),
> + jiffies_to_usecs(chip->timeout_d));
> + }
> +
> + if (chip->duration_adjusted) {
> + dev_info(&chip->dev,
> + HW_ERR "Adjusted durations: short %u->%uus"
> + " medium %u->%uus long %u->%uus\n",
> + jiffies_to_usecs(orig_duration[TPM_SHORT]),
> + jiffies_to_usecs(chip->duration[TPM_SHORT]),
> + jiffies_to_usecs(orig_duration[TPM_MEDIUM]),
> + jiffies_to_usecs(chip->duration[TPM_MEDIUM]),
> + jiffies_to_usecs(orig_duration[TPM_LONG]),
> + jiffies_to_usecs(chip->duration[TPM_LONG]));
> + }
> +
> return 0;
> }
> EXPORT_SYMBOL_GPL(tpm_get_timeouts);
> diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
> index e62fdeb..f013664 100644
> --- a/drivers/char/tpm/tpm_tis_core.c
> +++ b/drivers/char/tpm/tpm_tis_core.c
> @@ -398,37 +398,25 @@ static int tpm_tis_send(struct tpm_chip *chip, u8 *buf, size_t len)
> return rc;
> }
>
> -struct tis_vendor_timeout_override {
> - u32 did_vid;
> - unsigned long timeout_us[4];
> -};
> -
> -static const struct tis_vendor_timeout_override vendor_timeout_overrides[] = {
> - /* Atmel 3204 */
> - { 0x32041114, { (TIS_SHORT_TIMEOUT*1000), (TIS_LONG_TIMEOUT*1000),
> - (TIS_SHORT_TIMEOUT*1000), (TIS_SHORT_TIMEOUT*1000) } },
> -};
> -
> -static bool tpm_tis_update_timeouts(struct tpm_chip *chip,
> - unsigned long *timeout_cap)
> +static void tpm_tis_update_timeouts(struct tpm_chip *chip)
> {
> struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
> - int i, rc;
> + int rc;
> u32 did_vid;
>
> rc = tpm_tis_read32(priv, TPM_DID_VID(0), &did_vid);
> if (rc < 0)
> return rc;
>
> - for (i = 0; i != ARRAY_SIZE(vendor_timeout_overrides); i++) {
> - if (vendor_timeout_overrides[i].did_vid != did_vid)
> - continue;
> - memcpy(timeout_cap, vendor_timeout_overrides[i].timeout_us,
> - sizeof(vendor_timeout_overrides[i].timeout_us));
> - return true;
> + switch (did_vid) {
> + case 0x32041114: /* Atmel 3204 */
> + chip->timeout_a = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
> + chip->timeout_b = msecs_to_jiffies(TIS_LONG_TIMEOUT);
> + chip->timeout_c = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
> + chip->timeout_d = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
> + chip->timeout_adjusted = true;
> + break;

Is this needed if we have the special case for milliseconds in
tpm_get_timeouts?

> }
> -
> - return false;
> }
>
> /*
> diff --git a/include/linux/tpm.h b/include/linux/tpm.h
> index 706e63e..2380ebf 100644
> --- a/include/linux/tpm.h
> +++ b/include/linux/tpm.h
> @@ -41,8 +41,7 @@ struct tpm_class_ops {
> int (*send) (struct tpm_chip *chip, u8 *buf, size_t len);
> void (*cancel) (struct tpm_chip *chip);
> u8 (*status) (struct tpm_chip *chip);
> - bool (*update_timeouts)(struct tpm_chip *chip,
> - unsigned long *timeout_cap);
> + void (*update_timeouts)(struct tpm_chip *chip);
>
> };
>
> --
> 1.9.1
>

/Jarkko

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