From c82a330ceceda28304e37bab35128fa0c9c7f172 Mon Sep 17 00:00:00 2001 From: Tomas Winkler Date: Fri, 19 Oct 2018 21:22:57 +0300 Subject: tpm: factor out tpm 1.x pm suspend flow into tpm1-cmd.c Factor out TPM 1.x suspend flow from tpm-interface.c into a new function tpm1_pm_suspend() in tpm1-cmd.c Signed-off-by: Tomas Winkler Reviewed-by: Jarkko Sakkinen Tested-by: Jarkko Sakkinen Signed-off-by: Jarkko Sakkinen --- drivers/char/tpm/tpm1-cmd.c | 61 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 61 insertions(+) (limited to 'drivers/char/tpm/tpm1-cmd.c') diff --git a/drivers/char/tpm/tpm1-cmd.c b/drivers/char/tpm/tpm1-cmd.c index a69a02366c32..3bd9f1fa77ce 100644 --- a/drivers/char/tpm/tpm1-cmd.c +++ b/drivers/char/tpm/tpm1-cmd.c @@ -666,3 +666,64 @@ out: rc = -ENODEV; return rc; } + +#define TPM_ORD_SAVESTATE 152 +#define SAVESTATE_RESULT_SIZE 10 +static const struct tpm_input_header savestate_header = { + .tag = cpu_to_be16(TPM_TAG_RQU_COMMAND), + .length = cpu_to_be32(10), + .ordinal = cpu_to_be32(TPM_ORD_SAVESTATE) +}; + +/** + * tpm1_pm_suspend() - pm suspend handler + * @chip: TPM chip to use. + * @tpm_suspend_pcr: flush pcr for buggy TPM chips. + * + * The functions saves the TPM state to be restored on resume. + * + * Return: + * * 0 on success, + * * < 0 on error. + */ +int tpm1_pm_suspend(struct tpm_chip *chip, int tpm_suspend_pcr) +{ + u8 dummy_hash[TPM_DIGEST_SIZE] = { 0 }; + struct tpm_cmd_t cmd; + int rc, try; + + /* for buggy tpm, flush pcrs with extend to selected dummy */ + if (tpm_suspend_pcr) + rc = tpm1_pcr_extend(chip, tpm_suspend_pcr, dummy_hash, + "extending dummy pcr before suspend"); + + /* now do the actual savestate */ + for (try = 0; try < TPM_RETRY; try++) { + cmd.header.in = savestate_header; + rc = tpm_transmit_cmd(chip, NULL, &cmd, SAVESTATE_RESULT_SIZE, + 0, 0, NULL); + + /* + * If the TPM indicates that it is too busy to respond to + * this command then retry before giving up. It can take + * several seconds for this TPM to be ready. + * + * This can happen if the TPM has already been sent the + * SaveState command before the driver has loaded. TCG 1.2 + * specification states that any communication after SaveState + * may cause the TPM to invalidate previously saved state. + */ + if (rc != TPM_WARN_RETRY) + break; + tpm_msleep(TPM_TIMEOUT_RETRY); + } + + if (rc) + dev_err(&chip->dev, "Error (%d) sending savestate before suspend\n", + rc); + else if (try > 0) + dev_warn(&chip->dev, "TPM savestate took %dms\n", + try * TPM_TIMEOUT_RETRY); + + return rc; +} -- cgit v1.2.3