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Subject[PATCH] tpm_tis: Use timeouts returned from TPM
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The current TPM TIS driver in git discards the timeout values returned
from the TPM. The check of the response packet needs to consider that
the return_code field is 0 on success and the size of the expected
packet is equivalent to the header size + u32 length indicator for the
TPM_GetCapability() result + 3 timeout indicators of type u32.

I am also adding a sysfs entry 'timeouts' showing the timeouts that are
being used.


Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>

diff --git a/drivers/char/tpm/tpm.c b/drivers/char/tpm/tpm.c
index 1f46f1c..ef9ca1e 100644
--- a/drivers/char/tpm/tpm.c
+++ b/drivers/char/tpm/tpm.c
@@ -575,9 +575,11 @@ duration:
if (rc)
return;

- if (be32_to_cpu(tpm_cmd.header.out.return_code)
- != 3 * sizeof(u32))
+ if (be32_to_cpu(tpm_cmd.header.out.return_code) != 0 ||
+ be32_to_cpu(tpm_cmd.header.out.length)
+ != sizeof(tpm_cmd.header.out) + sizeof(u32) + 3 * sizeof(u32))
return;
+
duration_cap = &tpm_cmd.params.getcap_out.cap.duration;
chip->vendor.duration[TPM_SHORT] =
usecs_to_jiffies(be32_to_cpu(duration_cap->tpm_short));
@@ -937,6 +939,18 @@ ssize_t tpm_show_caps_1_2(struct device * dev,
}
EXPORT_SYMBOL_GPL(tpm_show_caps_1_2);

+ssize_t tpm_show_timeouts(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct tpm_chip *chip = dev_get_drvdata(dev);
+
+ return sprintf(buf, "%d %d %d\n",
+ jiffies_to_usecs(chip->vendor.duration[TPM_SHORT]),
+ jiffies_to_usecs(chip->vendor.duration[TPM_MEDIUM]),
+ jiffies_to_usecs(chip->vendor.duration[TPM_LONG]));
+}
+EXPORT_SYMBOL_GPL(tpm_show_timeouts);
+
ssize_t tpm_store_cancel(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 72ddb03..d84ff77 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -56,6 +56,8 @@ extern ssize_t tpm_show_owned(struct device *, struct device_attribute *attr,
char *);
extern ssize_t tpm_show_temp_deactivated(struct device *,
struct device_attribute *attr, char *);
+extern ssize_t tpm_show_timeouts(struct device *,
+ struct device_attribute *attr, char *);

struct tpm_chip;

diff --git a/drivers/char/tpm/tpm_tis.c b/drivers/char/tpm/tpm_tis.c
index c17a305..3e1f2bb 100644
--- a/drivers/char/tpm/tpm_tis.c
+++ b/drivers/char/tpm/tpm_tis.c
@@ -376,6 +376,7 @@ static DEVICE_ATTR(temp_deactivated, S_IRUGO, tpm_show_temp_deactivated,
NULL);
static DEVICE_ATTR(caps, S_IRUGO, tpm_show_caps_1_2, NULL);
static DEVICE_ATTR(cancel, S_IWUSR | S_IWGRP, NULL, tpm_store_cancel);
+static DEVICE_ATTR(timeouts, S_IRUGO, tpm_show_timeouts, NULL);

static struct attribute *tis_attrs[] = {
&dev_attr_pubek.attr,
@@ -385,7 +386,8 @@ static struct attribute *tis_attrs[] = {
&dev_attr_owned.attr,
&dev_attr_temp_deactivated.attr,
&dev_attr_caps.attr,
- &dev_attr_cancel.attr, NULL,
+ &dev_attr_cancel.attr,
+ &dev_attr_timeouts.attr, NULL,
};

static struct attribute_group tis_attr_grp = {


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