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    SubjectRe: [PATCH] tpm: remove redundant code from self-test functions
    On Wed, Mar 30, 2016 at 04:20:45PM +0300, Jarkko Sakkinen wrote:
    > Self-test functions construct PCR read calls by ad hoc, which is only a
    > waste space. Use instead tpm_pcr_read_dev (renamed as tpm1_pcr_read() by
    > this commit) in tpm_do_selftest and tpm2_pcr_read() in
    > tpm2_do_selftest() functions in order to remove the duplicate code.
    >
    > Patch can be tested easily tested by running the a kernel with this
    > patch compiled in since self-test is done when the a device driver
    > initializes.

    This is now fixed version (I forgot to squash one fixup to the previous
    version). This could use peer test preferably with a FIFO device. It is
    easy as one only needs to load the driver and see that there are no
    errors in dmesg from self-additions. As an additional measure on a TPM
    1.x device outputting 'pcrs' file could be a good idea.

    /Jarkko

    > Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
    > ---
    > drivers/char/tpm/tpm-interface.c | 14 +++++---------
    > drivers/char/tpm/tpm-sysfs.c | 2 +-
    > drivers/char/tpm/tpm.h | 2 +-
    > drivers/char/tpm/tpm2-cmd.c | 14 ++------------
    > 4 files changed, 9 insertions(+), 23 deletions(-)
    >
    > diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
    > index 5397b64..0c8140f 100644
    > --- a/drivers/char/tpm/tpm-interface.c
    > +++ b/drivers/char/tpm/tpm-interface.c
    > @@ -1,6 +1,6 @@
    > /*
    > * Copyright (C) 2004 IBM Corporation
    > - * Copyright (C) 2014 Intel Corporation
    > + * Copyright (C) 2014, 2016 Intel Corporation
    > *
    > * Authors:
    > * Leendert van Doorn <leendert@watson.ibm.com>
    > @@ -666,7 +666,7 @@ static struct tpm_input_header pcrread_header = {
    > .ordinal = TPM_ORDINAL_PCRREAD
    > };
    >
    > -int tpm_pcr_read_dev(struct tpm_chip *chip, int pcr_idx, u8 *res_buf)
    > +int tpm1_pcr_read(struct tpm_chip *chip, int pcr_idx, u8 *res_buf)
    > {
    > int rc;
    > struct tpm_cmd_t cmd;
    > @@ -676,7 +676,7 @@ int tpm_pcr_read_dev(struct tpm_chip *chip, int pcr_idx, u8 *res_buf)
    > rc = tpm_transmit_cmd(chip, &cmd, READ_PCR_RESULT_SIZE,
    > "attempting to read a pcr value");
    >
    > - if (rc == 0)
    > + if (rc == 0 && res_buf)
    > memcpy(res_buf, cmd.params.pcrread_out.pcr_result,
    > TPM_DIGEST_SIZE);
    > return rc;
    > @@ -728,7 +728,7 @@ int tpm_pcr_read(u32 chip_num, int pcr_idx, u8 *res_buf)
    > 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);
    > + rc = tpm1_pcr_read(chip, pcr_idx, res_buf);
    > tpm_put_ops(chip);
    > return rc;
    > }
    > @@ -793,7 +793,6 @@ int tpm_do_selftest(struct tpm_chip *chip)
    > unsigned int loops;
    > unsigned int delay_msec = 100;
    > unsigned long duration;
    > - struct tpm_cmd_t cmd;
    >
    > duration = tpm_calc_ordinal_duration(chip, TPM_ORD_CONTINUE_SELFTEST);
    >
    > @@ -808,9 +807,7 @@ int tpm_do_selftest(struct tpm_chip *chip)
    >
    > do {
    > /* Attempt to read a PCR value */
    > - cmd.header.in = pcrread_header;
    > - cmd.params.pcrread_in.pcr_idx = cpu_to_be32(0);
    > - rc = tpm_transmit(chip, (u8 *) &cmd, READ_PCR_RESULT_SIZE);
    > + rc = tpm1_pcr_read(chip, 0, NULL);
    > /* 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. */
    > @@ -825,7 +822,6 @@ int tpm_do_selftest(struct tpm_chip *chip)
    > if (rc < TPM_HEADER_SIZE)
    > return -EFAULT;
    >
    > - rc = be32_to_cpu(cmd.header.out.return_code);
    > if (rc == TPM_ERR_DISABLED || rc == TPM_ERR_DEACTIVATED) {
    > dev_info(&chip->dev,
    > "TPM is disabled/deactivated (0x%X)\n", rc);
    > diff --git a/drivers/char/tpm/tpm-sysfs.c b/drivers/char/tpm/tpm-sysfs.c
    > index 34e7fc7..48e30bd 100644
    > --- a/drivers/char/tpm/tpm-sysfs.c
    > +++ b/drivers/char/tpm/tpm-sysfs.c
    > @@ -101,7 +101,7 @@ static ssize_t pcrs_show(struct device *dev, struct device_attribute *attr,
    >
    > num_pcrs = be32_to_cpu(cap.num_pcrs);
    > for (i = 0; i < num_pcrs; i++) {
    > - rc = tpm_pcr_read_dev(chip, i, digest);
    > + rc = tpm1_pcr_read(chip, i, digest);
    > if (rc)
    > break;
    > str += sprintf(str, "PCR-%02d: ", i);
    > diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
    > index cd780c7..89740db 100644
    > --- a/drivers/char/tpm/tpm.h
    > +++ b/drivers/char/tpm/tpm.h
    > @@ -511,7 +511,7 @@ extern void tpm_chip_unregister(struct tpm_chip *chip);
    > int tpm_sysfs_add_device(struct tpm_chip *chip);
    > void tpm_sysfs_del_device(struct tpm_chip *chip);
    >
    > -int tpm_pcr_read_dev(struct tpm_chip *chip, int pcr_idx, u8 *res_buf);
    > +int tpm1_pcr_read(struct tpm_chip *chip, int pcr_idx, u8 *res_buf);
    >
    > #ifdef CONFIG_ACPI
    > extern void tpm_add_ppi(struct tpm_chip *chip);
    > diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
    > index 5fc0e7c..afe8d47 100644
    > --- a/drivers/char/tpm/tpm2-cmd.c
    > +++ b/drivers/char/tpm/tpm2-cmd.c
    > @@ -284,7 +284,7 @@ int tpm2_pcr_read(struct tpm_chip *chip, int pcr_idx, u8 *res_buf)
    >
    > rc = tpm_transmit_cmd(chip, &cmd, sizeof(cmd),
    > "attempting to read a pcr value");
    > - if (rc == 0) {
    > + if (rc == 0 && res_buf) {
    > buf = cmd.params.pcrread_out.digest;
    > memcpy(res_buf, buf, TPM_DIGEST_SIZE);
    > }
    > @@ -861,7 +861,6 @@ int tpm2_do_selftest(struct tpm_chip *chip)
    > unsigned int loops;
    > unsigned int delay_msec = 100;
    > unsigned long duration;
    > - struct tpm2_cmd cmd;
    > int i;
    >
    > duration = tpm2_calc_ordinal_duration(chip, TPM2_CC_SELF_TEST);
    > @@ -874,19 +873,10 @@ int tpm2_do_selftest(struct tpm_chip *chip)
    >
    > for (i = 0; i < loops; i++) {
    > /* Attempt to read a PCR value */
    > - cmd.header.in = tpm2_pcrread_header;
    > - cmd.params.pcrread_in.pcr_selects_cnt = cpu_to_be32(1);
    > - cmd.params.pcrread_in.hash_alg = cpu_to_be16(TPM2_ALG_SHA1);
    > - cmd.params.pcrread_in.pcr_select_size = TPM2_PCR_SELECT_MIN;
    > - cmd.params.pcrread_in.pcr_select[0] = 0x01;
    > - cmd.params.pcrread_in.pcr_select[1] = 0x00;
    > - cmd.params.pcrread_in.pcr_select[2] = 0x00;
    > -
    > - rc = tpm_transmit_cmd(chip, (u8 *) &cmd, sizeof(cmd), NULL);
    > + rc = tpm2_pcr_read(chip, 0, NULL);
    > if (rc < 0)
    > break;
    >
    > - rc = be32_to_cpu(cmd.header.out.return_code);
    > if (rc != TPM2_RC_TESTING)
    > break;
    >
    > --
    > 1.9.1
    >

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