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Message-Id: <fedbdc12-4e50-b057-0d7f-ac9c0afa6daa@linux.ibm.com>
Date: Tue, 13 Nov 2018 20:47:43 -0500
From: Stefan Berger <stefanb@...ux.ibm.com>
To: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>,
linux-integrity@...r.kernel.org
Cc: linux-security-module@...r.kernel.org,
James Bottomley <James.Bottomley@...senPartnership.com>,
Tomas Winkler <tomas.winkler@...el.com>,
Tadeusz Struk <tadeusz.struk@...el.com>,
Stefan Berger <stefanb@...ux.vnet.ibm.com>,
Nayna Jain <nayna@...ux.ibm.com>,
Peter Huewe <peterhuewe@....de>,
Jason Gunthorpe <jgg@...pe.ca>, Arnd Bergmann <arnd@...db.de>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v7 15/17] tpm: introduce tpm_chip_start() and
tpm_chip_stop()
On 11/13/18 1:36 PM, Jarkko Sakkinen wrote:
> Encapsulate power gating and locality functionality to tpm_chip_start()
> and tpm_chip_stop() in order to clean up the branching mess in
> tpm_transmit().
>
> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
> ---
> drivers/char/tpm/tpm-chip.c | 110 +++++++++++++++++++++++++++++++
> drivers/char/tpm/tpm-interface.c | 87 +-----------------------
> drivers/char/tpm/tpm.h | 2 +
> 3 files changed, 115 insertions(+), 84 deletions(-)
>
> diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
> index 157505b0f755..65f1561eba81 100644
> --- a/drivers/char/tpm/tpm-chip.c
> +++ b/drivers/char/tpm/tpm-chip.c
> @@ -37,6 +37,116 @@ struct class *tpm_class;
> struct class *tpmrm_class;
> dev_t tpm_devt;
>
> +static int tpm_request_locality(struct tpm_chip *chip, unsigned int flags)
> +{
> + int rc;
> +
> + if (flags & TPM_TRANSMIT_NESTED)
> + return 0;
> +
> + if (!chip->ops->request_locality)
> + return 0;
> +
> + rc = chip->ops->request_locality(chip, 0);
> + if (rc < 0)
> + return rc;
> +
> + chip->locality = rc;
> + return 0;
> +}
> +
> +static void tpm_relinquish_locality(struct tpm_chip *chip, unsigned int flags)
> +{
> + int rc;
> +
> + if (flags & TPM_TRANSMIT_NESTED)
> + return;
> +
> + if (!chip->ops->relinquish_locality)
> + return;
> +
> + rc = chip->ops->relinquish_locality(chip, chip->locality);
> + if (rc)
> + dev_err(&chip->dev, "%s: : error %d\n", __func__, rc);
> +
> + chip->locality = -1;
> +}
> +
> +static int tpm_cmd_ready(struct tpm_chip *chip, unsigned int flags)
> +{
> + if (flags & TPM_TRANSMIT_NESTED)
> + return 0;
> +
> + if (!chip->ops->cmd_ready)
> + return 0;
> +
> + return chip->ops->cmd_ready(chip);
> +}
> +
> +static int tpm_go_idle(struct tpm_chip *chip, unsigned int flags)
> +{
> + if (flags & TPM_TRANSMIT_NESTED)
> + return 0;
> +
> + if (!chip->ops->go_idle)
> + return 0;
> +
> + return chip->ops->go_idle(chip);
> +}
> +
> +/**
> + * tpm_chip_start() - power on the TPM
> + * @chip: a TPM chip to use
> + * @flags: TPM transmit flags
> + *
> + * Return:
> + * * The response length - OK
> + * * -errno - A system error
> + */
> +int tpm_chip_start(struct tpm_chip *chip, unsigned int flags)
> +{
> + int ret;
> +
> + if (chip->ops->clk_enable)
> + chip->ops->clk_enable(chip, true);
> +
> + if (chip->locality == -1) {
> + ret = tpm_request_locality(chip, flags);
> + if (ret) {
> + chip->ops->clk_enable(chip, false);
> + return ret;
> + }
> + }
> +
> + ret = tpm_cmd_ready(chip, flags);
> + if (ret) {
> + tpm_relinquish_locality(chip, flags);
> + if (chip->ops->clk_enable)
> + chip->ops->clk_enable(chip, false);
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +/**
> + * tpm_chip_stop() - power off the TPM
> + * @chip: a TPM chip to use
> + * @flags: TPM transmit flags
> + *
> + * Return:
> + * * The response length - OK
> + * * -errno - A system error
> + */
> +void tpm_chip_stop(struct tpm_chip *chip, unsigned int flags)
> +{
> + tpm_go_idle(chip, flags);
> + tpm_relinquish_locality(chip, flags);
> + if (chip->ops->clk_enable)
> + chip->ops->clk_enable(chip, false);
> +}
> +
> +
> /**
> * tpm_try_get_ops() - Get a ref to the tpm_chip
> * @chip: Chip to ref
> diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
> index 5865b9671d20..888c9923fca1 100644
> --- a/drivers/char/tpm/tpm-interface.c
> +++ b/drivers/char/tpm/tpm-interface.c
> @@ -62,64 +62,6 @@ unsigned long tpm_calc_ordinal_duration(struct tpm_chip *chip, u32 ordinal)
> }
> EXPORT_SYMBOL_GPL(tpm_calc_ordinal_duration);
>
> -static int tpm_request_locality(struct tpm_chip *chip, unsigned int flags)
> -{
> - int rc;
> -
> - if (flags & TPM_TRANSMIT_NESTED)
> - return 0;
> -
> - if (!chip->ops->request_locality)
> - return 0;
> -
> - rc = chip->ops->request_locality(chip, 0);
> - if (rc < 0)
> - return rc;
> -
> - chip->locality = rc;
> -
> - return 0;
> -}
> -
> -static void tpm_relinquish_locality(struct tpm_chip *chip, unsigned int flags)
> -{
> - int rc;
> -
> - if (flags & TPM_TRANSMIT_NESTED)
> - return;
> -
> - if (!chip->ops->relinquish_locality)
> - return;
> -
> - rc = chip->ops->relinquish_locality(chip, chip->locality);
> - if (rc)
> - dev_err(&chip->dev, "%s: : error %d\n", __func__, rc);
> -
> - chip->locality = -1;
> -}
> -
> -static int tpm_cmd_ready(struct tpm_chip *chip, unsigned int flags)
> -{
> - if (flags & TPM_TRANSMIT_NESTED)
> - return 0;
> -
> - if (!chip->ops->cmd_ready)
> - return 0;
> -
> - return chip->ops->cmd_ready(chip);
> -}
> -
> -static int tpm_go_idle(struct tpm_chip *chip, unsigned int flags)
> -{
> - if (flags & TPM_TRANSMIT_NESTED)
> - return 0;
> -
> - if (!chip->ops->go_idle)
> - return 0;
> -
> - return chip->ops->go_idle(chip);
> -}
> -
> static ssize_t tpm_try_transmit(struct tpm_chip *chip, u8 *buf, size_t bufsiz,
> unsigned int flags)
> {
> @@ -212,7 +154,6 @@ ssize_t tpm_transmit(struct tpm_chip *chip, u8 *buf, size_t bufsiz,
> /* space for header and handles */
> u8 save[TPM_HEADER_SIZE + 3*sizeof(u32)];
> unsigned int delay_msec = TPM2_DURATION_SHORT;
> - bool has_locality = false;
> u32 rc = 0;
> ssize_t ret;
> const size_t save_size = min(sizeof(save), bufsiz);
> @@ -227,34 +168,12 @@ ssize_t tpm_transmit(struct tpm_chip *chip, u8 *buf, size_t bufsiz,
> memcpy(save, buf, save_size);
>
> for (;;) {
> - if (chip->ops->clk_enable != NULL)
> - chip->ops->clk_enable(chip, true);
> -
> - if (chip->locality == -1) {
> - ret = tpm_request_locality(chip, flags);
> - if (ret)
> - goto out_locality;
> - has_locality = true;
> - }
> -
> - ret = tpm_cmd_ready(chip, flags);
> + ret = tpm_chip_start(chip, flags);
> if (ret)
> - goto out_locality;
> -
> + return ret;
> ret = tpm_try_transmit(chip, buf, bufsiz, flags);
> + tpm_chip_stop(chip, flags);
>
> - /* This may fail but do not override ret. */
> - tpm_go_idle(chip, flags);
> -
> -out_locality:
> - if (has_locality)
> - tpm_relinquish_locality(chip, flags);
> -
> - if (chip->ops->clk_enable != NULL)
> - chip->ops->clk_enable(chip, false);
> -
> - if (ret < 0)
> - break;
I think this should stay.
> rc = be32_to_cpu(header->return_code);
> if (rc != TPM2_RC_RETRY && rc != TPM2_RC_TESTING)
> break;
> diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
> index c7c06de651a0..c42a75710b70 100644
> --- a/drivers/char/tpm/tpm.h
> +++ b/drivers/char/tpm/tpm.h
> @@ -523,6 +523,8 @@ static inline void tpm_msleep(unsigned int delay_msec)
> delay_msec * 1000);
> };
>
> +int tpm_chip_start(struct tpm_chip *chip, unsigned int flags);
> +void tpm_chip_stop(struct tpm_chip *chip, unsigned int flags);
> struct tpm_chip *tpm_find_get_ops(struct tpm_chip *chip);
> __must_check int tpm_try_get_ops(struct tpm_chip *chip);
> void tpm_put_ops(struct tpm_chip *chip);
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