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Message-ID: <20180123125426.t6xjgrqcfbkmvkdl@linux.intel.com>
Date: Tue, 23 Jan 2018 14:54:26 +0200
From: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
To: Tomas Winkler <tomas.winkler@...el.com>, '@...ux.intel.com
Cc: Jason Gunthorpe <jgunthorpe@...idianresearch.com>,
Alexander Usyskin <alexander.usyskin@...el.com>,
tpmdd-devel@...ts.sourceforge.net, linux-integrity@...r.kernel.org,
linux-security-module@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/3] tpm: cmd_ready command can be issued only after
granting locality
On Tue, Jan 23, 2018 at 01:27:29PM +0200, Tomas Winkler wrote:
> The correct sequence is to first request locality and only after
> that perform cmd_ready handshake, otherwise the hardware will drop
> the subsequent message as from the device point of view the cmd_ready
> handshake wasn't performed. Symmetrically locality has to be relinquished
> only after going idle handshake has completed, this requires that
> go_idle has to poll for the completion.
>
> The issue is only visible on devices that support multiple localities.
>
> Signed-off-by: Tomas Winkler <tomas.winkler@...el.com>
Thank you!
> ---
> drivers/char/tpm/tpm-interface.c | 12 ++---
> drivers/char/tpm/tpm_crb.c | 95 ++++++++++++++++++++++++++--------------
> 2 files changed, 70 insertions(+), 37 deletions(-)
>
> diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
> index 76df4fbcf089..197fda39aab5 100644
> --- a/drivers/char/tpm/tpm-interface.c
> +++ b/drivers/char/tpm/tpm-interface.c
> @@ -422,8 +422,6 @@ ssize_t tpm_transmit(struct tpm_chip *chip, struct tpm_space *space,
> if (!(flags & TPM_TRANSMIT_UNLOCKED))
> mutex_lock(&chip->tpm_mutex);
>
> - if (chip->dev.parent)
> - pm_runtime_get_sync(chip->dev.parent);
>
> if (chip->ops->clk_enable != NULL)
> chip->ops->clk_enable(chip, true);
> @@ -439,6 +437,9 @@ ssize_t tpm_transmit(struct tpm_chip *chip, struct tpm_space *space,
> chip->locality = rc;
> }
>
> + if (chip->dev.parent)
> + pm_runtime_get_sync(chip->dev.parent);
> +
> rc = tpm2_prepare_space(chip, space, ordinal, buf);
> if (rc)
> goto out;
> @@ -499,17 +500,18 @@ ssize_t tpm_transmit(struct tpm_chip *chip, struct tpm_space *space,
> rc = tpm2_commit_space(chip, space, ordinal, buf, &len);
>
> out:
> + if (chip->dev.parent)
> + pm_runtime_put_sync(chip->dev.parent);
> +
> if (need_locality && chip->ops->relinquish_locality) {
> chip->ops->relinquish_locality(chip, chip->locality);
> chip->locality = -1;
> }
> +
> out_no_locality:
> if (chip->ops->clk_enable != NULL)
> chip->ops->clk_enable(chip, false);
>
> - if (chip->dev.parent)
> - pm_runtime_put_sync(chip->dev.parent);
> -
> if (!(flags & TPM_TRANSMIT_UNLOCKED))
> mutex_unlock(&chip->tpm_mutex);
> return rc ? rc : len;
> diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c
> index 7b3c2a8aa9de..d174919c446d 100644
> --- a/drivers/char/tpm/tpm_crb.c
> +++ b/drivers/char/tpm/tpm_crb.c
> @@ -112,6 +112,25 @@ struct tpm2_crb_smc {
> u32 smc_func_id;
> };
>
> +static bool crb_wait_for_reg_32(u32 __iomem *reg, u32 mask, u32 value,
> + unsigned long timeout)
> +{
> + ktime_t start;
> + ktime_t stop;
> +
> + start = ktime_get();
> + stop = ktime_add(start, ms_to_ktime(timeout));
> +
> + do {
> + if ((ioread32(reg) & mask) == value)
> + return true;
> +
> + usleep_range(50, 100);
> + } while (ktime_before(ktime_get(), stop));
> +
> + return ((ioread32(reg) & mask) == value);
Not sure about the change of return statement. Is this worth of doing?
> +}
> +
> /**
> * crb_go_idle - request tpm crb device to go the idle state
> *
> @@ -128,7 +147,7 @@ struct tpm2_crb_smc {
> *
> * Return: 0 always
> */
> -static int __maybe_unused crb_go_idle(struct device *dev, struct crb_priv *priv)
> +static int crb_go_idle(struct device *dev, struct crb_priv *priv)
> {
> if ((priv->sm == ACPI_TPM2_START_METHOD) ||
> (priv->sm == ACPI_TPM2_COMMAND_BUFFER_WITH_START_METHOD) ||
> @@ -136,30 +155,17 @@ static int __maybe_unused crb_go_idle(struct device *dev, struct crb_priv *priv)
> return 0;
>
> iowrite32(CRB_CTRL_REQ_GO_IDLE, &priv->regs_t->ctrl_req);
> - /* we don't really care when this settles */
>
> + if (!crb_wait_for_reg_32(&priv->regs_t->ctrl_req,
> + CRB_CTRL_REQ_GO_IDLE/* mask */,
> + 0, /* value */
> + TPM2_TIMEOUT_C)) {
> + dev_warn(dev, "goIdle timed out\n");
> + return -ETIME;
> + }
> return 0;
> }
>
> -static bool crb_wait_for_reg_32(u32 __iomem *reg, u32 mask, u32 value,
> - unsigned long timeout)
> -{
> - ktime_t start;
> - ktime_t stop;
> -
> - start = ktime_get();
> - stop = ktime_add(start, ms_to_ktime(timeout));
> -
> - do {
> - if ((ioread32(reg) & mask) == value)
> - return true;
> -
> - usleep_range(50, 100);
> - } while (ktime_before(ktime_get(), stop));
> -
> - return false;
> -}
> -
> /**
> * crb_cmd_ready - request tpm crb device to enter ready state
> *
> @@ -175,8 +181,7 @@ static bool crb_wait_for_reg_32(u32 __iomem *reg, u32 mask, u32 value,
> *
> * Return: 0 on success -ETIME on timeout;
> */
> -static int __maybe_unused crb_cmd_ready(struct device *dev,
> - struct crb_priv *priv)
> +static int crb_cmd_ready(struct device *dev, struct crb_priv *priv)
> {
> if ((priv->sm == ACPI_TPM2_START_METHOD) ||
> (priv->sm == ACPI_TPM2_COMMAND_BUFFER_WITH_START_METHOD) ||
> @@ -195,11 +200,11 @@ static int __maybe_unused crb_cmd_ready(struct device *dev,
> return 0;
> }
>
> -static int crb_request_locality(struct tpm_chip *chip, int loc)
> +static int __crb_request_locality(struct device *dev,
> + struct crb_priv *priv, int loc)
> {
> - struct crb_priv *priv = dev_get_drvdata(&chip->dev);
> u32 value = CRB_LOC_STATE_LOC_ASSIGNED |
> - CRB_LOC_STATE_TPM_REG_VALID_STS;
> + CRB_LOC_STATE_TPM_REG_VALID_STS;
>
> if (!priv->regs_h)
> return 0;
> @@ -207,23 +212,36 @@ static int crb_request_locality(struct tpm_chip *chip, int loc)
> iowrite32(CRB_LOC_CTRL_REQUEST_ACCESS, &priv->regs_h->loc_ctrl);
> if (!crb_wait_for_reg_32(&priv->regs_h->loc_state, value, value,
> TPM2_TIMEOUT_C)) {
> - dev_warn(&chip->dev, "TPM_LOC_STATE_x.requestAccess timed out\n");
> + dev_warn(dev, "TPM_LOC_STATE_x.requestAccess timed out\n");
> return -ETIME;
> }
>
> return 0;
> }
>
> -static void crb_relinquish_locality(struct tpm_chip *chip, int loc)
> +static int crb_request_locality(struct tpm_chip *chip, int loc)
> {
> struct crb_priv *priv = dev_get_drvdata(&chip->dev);
>
> + return __crb_request_locality(&chip->dev, priv, loc);
> +}
> +
> +static void __crb_relinquish_locality(struct device *dev,
> + struct crb_priv *priv, int loc)
> +{
> if (!priv->regs_h)
> return;
>
> iowrite32(CRB_LOC_CTRL_RELINQUISH, &priv->regs_h->loc_ctrl);
> }
>
> +static void crb_relinquish_locality(struct tpm_chip *chip, int loc)
> +{
> + struct crb_priv *priv = dev_get_drvdata(&chip->dev);
> +
> + __crb_relinquish_locality(&chip->dev, priv, loc);
> +}
> +
> static u8 crb_status(struct tpm_chip *chip)
> {
> struct crb_priv *priv = dev_get_drvdata(&chip->dev);
> @@ -475,6 +493,10 @@ static int crb_map_io(struct acpi_device *device, struct crb_priv *priv,
> dev_warn(dev, FW_BUG "Bad ACPI memory layout");
> }
>
> + ret = __crb_request_locality(dev, priv, 0);
> + if (ret)
> + return ret;
> +
> priv->regs_t = crb_map_res(dev, priv, &io_res, buf->control_address,
> sizeof(struct crb_regs_tail));
> if (IS_ERR(priv->regs_t))
> @@ -531,6 +553,8 @@ static int crb_map_io(struct acpi_device *device, struct crb_priv *priv,
>
> crb_go_idle(dev, priv);
>
> + __crb_relinquish_locality(dev, priv, 0);
> +
> return ret;
> }
>
> @@ -588,10 +612,14 @@ static int crb_acpi_add(struct acpi_device *device)
> chip->acpi_dev_handle = device->handle;
> chip->flags = TPM_CHIP_FLAG_TPM2;
>
> - rc = crb_cmd_ready(dev, priv);
> + rc = __crb_request_locality(dev, priv, 0);
> if (rc)
> return rc;
>
> + rc = crb_cmd_ready(dev, priv);
> + if (rc)
> + goto out;
> +
> pm_runtime_get_noresume(dev);
> pm_runtime_set_active(dev);
> pm_runtime_enable(dev);
> @@ -601,12 +629,15 @@ static int crb_acpi_add(struct acpi_device *device)
> crb_go_idle(dev, priv);
> pm_runtime_put_noidle(dev);
> pm_runtime_disable(dev);
> - return rc;
> + goto out;
> }
>
> - pm_runtime_put(dev);
> + pm_runtime_put_sync(dev);
Change to put_sync is needed so that the idle handshake gets completed?
>
> - return 0;
> +out:
> + __crb_relinquish_locality(dev, priv, 0);
> +
> + return rc;
> }
>
> static int crb_acpi_remove(struct acpi_device *device)
> --
> 2.14.3
>
/Jarkko
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