static ssize_t pcrs_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
cap_t cap;
u8 digest[TPM_DIGEST_SIZE];
ssize_t rc;
int i, j, num_pcrs;
char *str = buf;
struct tpm_chip *chip = to_tpm_chip(dev);
rc = tpm_getcap(chip, TPM_CAP_PROP_PCR, &cap,
"attempting to determine the number of PCRS");
if (rc)
return 0;
num_pcrs = be32_to_cpu(cap.num_pcrs);
for (i = 0; i < num_pcrs; i++) {
rc = tpm_pcr_read_dev(chip, i, digest);
if (rc)
break;
str += sprintf(str, "PCR-%02d: ", i);
for (j = 0; j < TPM_DIGEST_SIZE; j++)
str += sprintf(str, "%02X ", digest[j]);
str += sprintf(str, "\n");
}
return str - buf;
}
/**
* tpm_do_selftest - have the TPM continue its selftest and wait until it
* can receive further commands
* @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_do_selftest(struct tpm_chip *chip)
{
int rc;
unsigned int loops;
unsigned int delay_msec = 100;
unsigned long duration;
u8 dummy[TPM_DIGEST_SIZE];
duration = tpm_calc_ordinal_duration(chip, TPM_ORD_CONTINUE_SELFTEST);
loops = jiffies_to_msecs(duration) / delay_msec;
rc = tpm_continue_selftest(chip);
/* This may fail if there was no TPM driver during a suspend/resume
* cycle; some may return 10 (BAD_ORDINAL), others 28 (FAILEDSELFTEST)
*/
if (rc)
return rc;
do {
/* Attempt to read a PCR value */
rc = tpm_pcr_read_dev(chip, 0, dummy);
/* Some buggy TPMs will not respond to tpm_tis_ready() for
* around 300ms while the self test is ongoing, keep trying
* until the self test duration expires. */
if (rc == -ETIME) {
dev_info(
&chip->dev, HW_ERR
"TPM command timed out during continue self test");
msleep(delay_msec);
continue;
}
if (rc == TPM_ERR_DISABLED || rc == TPM_ERR_DEACTIVATED) {
dev_info(&chip->dev,
"TPM is disabled/deactivated (0x%X)\n", rc);
/* TPM is disabled and/or deactivated; driver can
* proceed and TPM does handle commands for
* suspend/resume correctly
*/
return 0;
}
if (rc != TPM_WARN_DOING_SELFTEST)
return rc;
msleep(delay_msec);
} while (--loops > 0);
return rc;
}
/**
* tpm_pcr_read - read a pcr value
* @chip_num: tpm idx # or ANY
* @pcr_idx: pcr idx to retrieve
* @res_buf: TPM_PCR value
* size of res_buf is 20 bytes (or NULL if you don't care)
*
* The TPM driver should be built-in, but for whatever reason it
* isn't, protect against the chip disappearing, by incrementing
* the module usage count.
*/
int tpm_pcr_read(u32 chip_num, int pcr_idx, u8 *res_buf)
{
struct tpm_chip *chip;
int rc;
chip = tpm_chip_find_get(chip_num);
if (chip == NULL)
return -ENODEV;
if (chip->flags & TPM_CHIP_FLAG_TPM2)
rc = tpm2_pcr_read(chip, pcr_idx, res_buf);
else
rc = tpm_pcr_read_dev(chip, pcr_idx, res_buf);
tpm_put_ops(chip);
return rc;
}
