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SubjectRe: [PATCH v2] tpm/tpm_crb: Access locality for only CRB_START method
On Sat, Aug 12, 2017 at 08:22:49PM -0500, Jiandi An wrote:
> For ARM64, the locality is handled by Trust Zone in FW.
> The layout does not have crb_regs_head. It is hitting
> the following line.
> dev_warn(dev, FW_BUG "Bad ACPI memory layout");
>
> Current code excludes CRB_FL_ACPI_START and when
> CRB_FL_CRB_SMC_START is added around the same time
> locality support is added, it should also be excluded.
> Change the if condition to be only for CRB_FL_CRB_START.
>
> For goIdle and cmdReady where code was excluding
> CRB_FL_ACPI_START only (do nothing for ACPI start method),
> CRB_FL_CRB_SMC_START was also excluded as ARM64 SMC start
> method does not have TPM_CRB_CTRL_REQ.
> Change the if condition to be only for CRB_FL_CRB_START
> in crb_go_idle() and crb_cmd_ready().
>
> Signed-off-by: Jiandi An <anjiandi@codeaurora.org>
> ---
> v2
> Changed if condition to CRB_FL_CRB_START for go idle
> and crb_cmd_ready per maintainer's comment.

What about platforms with firmware bug that they report only requiring
ACPI start but actually also require CRB start.

if (sm == ACPI_TPM2_START_METHOD ||
sm == ACPI_TPM2_COMMAND_BUFFER_WITH_START_METHOD)
priv->flags |= CRB_FL_ACPI_START;

I've encountered a platform that reports to require start method 2 (ACPI
start) while it actually requires start method 8.

That's why we have this nasty workaround:

/* The reason for the extra quirk is that the PTT in 4th Gen Core CPUs
* report only ACPI start but in practice seems to require both
* ACPI start and CRB start.
*/
if (sm == ACPI_TPM2_COMMAND_BUFFER || sm == ACPI_TPM2_MEMORY_MAPPED ||
!strcmp(acpi_device_hid(device), "MSFT0101"))
priv->flags |= CRB_FL_CRB_START;

Also, since start method 8 exist in the spec, it is a legit config.

>
> drivers/char/tpm/tpm_crb.c | 36 +++++++++++++++++-------------------
> 1 file changed, 17 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c
> index 8f0a98d..7a6735d 100644
> --- a/drivers/char/tpm/tpm_crb.c
> +++ b/drivers/char/tpm/tpm_crb.c
> @@ -128,18 +128,16 @@ struct tpm2_crb_smc {
> * Anyhow, we do not wait here as a consequent CMD_READY request
> * will be handled correctly even if idle was not completed.
> *
> - * The function does nothing for devices with ACPI-start method.
> + * The function does nothing for devices with ACPI-start method
> + * and SMC-start method.
> *
> * Return: 0 always
> */
> static int __maybe_unused crb_go_idle(struct device *dev, struct crb_priv *priv)
> {
> - if ((priv->flags & CRB_FL_ACPI_START) ||
> - (priv->flags & CRB_FL_CRB_SMC_START))
> - return 0;
> -
> - iowrite32(CRB_CTRL_REQ_GO_IDLE, &priv->regs_t->ctrl_req);
> - /* we don't really care when this settles */
> + if (priv->flags & CRB_FL_CRB_START)
> + iowrite32(CRB_CTRL_REQ_GO_IDLE, &priv->regs_t->ctrl_req);
> + /* we don't really care when this settles */
>
> return 0;
> }
> @@ -174,23 +172,23 @@ static bool crb_wait_for_reg_32(u32 __iomem *reg, u32 mask, u32 value,
> * The device should respond within TIMEOUT_C.
> *
> * The function does nothing for devices with ACPI-start method
> + * and SMC-start method.
> *
> * Return: 0 on success -ETIME on timeout;
> */
> static int __maybe_unused crb_cmd_ready(struct device *dev,
> struct crb_priv *priv)
> {
> - if ((priv->flags & CRB_FL_ACPI_START) ||
> - (priv->flags & CRB_FL_CRB_SMC_START))
> - return 0;
> -
> - iowrite32(CRB_CTRL_REQ_CMD_READY, &priv->regs_t->ctrl_req);
> - if (!crb_wait_for_reg_32(&priv->regs_t->ctrl_req,
> - CRB_CTRL_REQ_CMD_READY /* mask */,
> - 0, /* value */
> - TPM2_TIMEOUT_C)) {
> - dev_warn(dev, "cmdReady timed out\n");
> - return -ETIME;
> + if (priv->flags & CRB_FL_CRB_START)
> + {

The opening curly brace should be in the same line as the condition
statement.

> + iowrite32(CRB_CTRL_REQ_CMD_READY, &priv->regs_t->ctrl_req);
> + if (!crb_wait_for_reg_32(&priv->regs_t->ctrl_req,
> + CRB_CTRL_REQ_CMD_READY /* mask */,
> + 0, /* value */
> + TPM2_TIMEOUT_C)) {
> + dev_warn(dev, "cmdReady timed out\n");
> + return -ETIME;
> + }
> }
>
> return 0;
> @@ -458,7 +456,7 @@ static int crb_map_io(struct acpi_device *device, struct crb_priv *priv,
> * the control area, as one nice sane region except for some older
> * stuff that puts the control area outside the ACPI IO region.
> */
> - if (!(priv->flags & CRB_FL_ACPI_START)) {
> + if (priv->flags & CRB_FL_CRB_START) {
> if (buf->control_address == io_res.start +
> sizeof(*priv->regs_h))
> priv->regs_h = priv->iobase;
> --
> Jiandi An
> Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc.
> Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.
>

/Jarkko

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