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Message-ID: <20180618180406.GA20697@linux.intel.com>
Date: Mon, 18 Jun 2018 21:04:06 +0300
From: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
To: Tomas Winkler <tomas.winkler@...el.com>
Cc: Jason Gunthorpe <jgg@...pe.ca>,
Alexander Usyskin <alexander.usyskin@...el.com>,
linux-integrity@...r.kernel.org,
linux-security-module@...r.kernel.org,
linux-kernel@...r.kernel.org, stable@...r.kernel.org
Subject: Re: [PATCH v6] tpm: separate cmd_ready/go_idle from runtime_pm
On Fri, Jun 08, 2018 at 12:20:40AM +0300, Tomas Winkler wrote:
> We cannot use go_idle cmd_ready commands via runtime_pm handles
> as with the introduction of localities this is no longer an optional
> feature, while runtime pm can be not enabled.
> Though cmd_ready/go_idle provides a power saving, it's also a part of
> TPM2 protocol and should be called explicitly.
> This patch exposes cmd_read/go_idle via tpm class ops and removes
> runtime pm support as it is not used by any driver.
>
> A new tpm transmit flag is added TPM_TRANSMIT_NESTED, which implies
> TPM_TRANSMIT_UNLOCKED and TPM_TRANSMIT_RAW. Both are needed to resolve
> tpm spaces and locality request recursive calls to tpm_transmit().
>
> New wrappers are added tpm_cmd_ready() and tpm_go_idle() to
> streamline tpm_try_transmit code.
>
> tpm_crb no longer needs own power saving functions and can drop using
> tpm_pm_suspend/resume.
>
> This patch cannot be really separated from the locality fix.
> Fixes: 888d867df441 (tpm: cmd_ready command can be issued only after granting locality)
>
>
> Cc: stable@...r.kernel.org
> Fixes: 888d867df441 (tpm: cmd_ready command can be issued only after granting locality)
> Signed-off-by: Tomas Winkler <tomas.winkler@...el.com>
> ---
> V2-3:resent
> V4: 1. Use tpm_pm_suspend/resume in tpm_crb
> 2. Drop cmd_ready/go_idle around tpm_chip_register, as there is no
> usage counter like in runtime_pm.
> V5: 1. add tpm_cmd_ready and tpm_go_idle wrappers.
> 2. Abuse TPM_TRANSMIT_UNLOCKED flag to resolve tpm space
> recursion.
> V6: 1. Add new flags TPM_TRANSMIT_NESTED which implies
> TPM_TRANSMIT_UNLOCKED and TPM_TRANSMIT_RAW, as not all
> unlocked flows are recursive i.e. tpm2_unseal_trusted.
>
> drivers/char/tpm/tpm-interface.c | 51 +++++++++++++++----
> drivers/char/tpm/tpm.h | 13 ++++-
> drivers/char/tpm/tpm2-space.c | 12 ++---
> drivers/char/tpm/tpm_crb.c | 101 ++++++++++----------------------------
> drivers/char/tpm/tpm_vtpm_proxy.c | 2 +-
> include/linux/tpm.h | 2 +
> 6 files changed, 88 insertions(+), 93 deletions(-)
>
> diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
> index e32f6e85dc6d..1abd8261651b 100644
> --- a/drivers/char/tpm/tpm-interface.c
> +++ b/drivers/char/tpm/tpm-interface.c
> @@ -29,7 +29,6 @@
> #include <linux/mutex.h>
> #include <linux/spinlock.h>
> #include <linux/freezer.h>
> -#include <linux/pm_runtime.h>
> #include <linux/tpm_eventlog.h>
>
> #include "tpm.h"
> @@ -369,10 +368,13 @@ static int tpm_validate_command(struct tpm_chip *chip,
> return -EINVAL;
> }
>
> -static int tpm_request_locality(struct tpm_chip *chip)
> +static int tpm_request_locality(struct tpm_chip *chip, unsigned int flags)
> {
> int rc;
>
> + if (flags & __TPM_TRANSMIT_RAW)
> + return 0;
> +
> if (!chip->ops->request_locality)
> return 0;
>
> @@ -385,10 +387,13 @@ static int tpm_request_locality(struct tpm_chip *chip)
> return 0;
> }
>
> -static void tpm_relinquish_locality(struct tpm_chip *chip)
> +static void tpm_relinquish_locality(struct tpm_chip *chip, unsigned int flags)
> {
> int rc;
>
> + if (flags & __TPM_TRANSMIT_RAW)
> + return;
> +
> if (!chip->ops->relinquish_locality)
> return;
>
> @@ -399,6 +404,28 @@ static void tpm_relinquish_locality(struct tpm_chip *chip)
> chip->locality = -1;
> }
>
> +static int tpm_cmd_ready(struct tpm_chip *chip, unsigned int flags)
> +{
> + if (flags & __TPM_TRANSMIT_RAW)
> + 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_RAW)
> + 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,
> struct tpm_space *space,
> u8 *buf, size_t bufsiz,
> @@ -449,14 +476,15 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip,
> /* Store the decision as chip->locality will be changed. */
> need_locality = chip->locality == -1;
>
> - if (!(flags & TPM_TRANSMIT_RAW) && need_locality) {
> - rc = tpm_request_locality(chip);
> + if (need_locality) {
> + rc = tpm_request_locality(chip, flags);
> if (rc < 0)
> goto out_no_locality;
> }
>
> - if (chip->dev.parent)
> - pm_runtime_get_sync(chip->dev.parent);
> + rc = tpm_cmd_ready(chip, flags);
> + if (rc)
> + goto out;
>
> rc = tpm2_prepare_space(chip, space, ordinal, buf);
> if (rc)
> @@ -516,13 +544,16 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip,
> }
>
> rc = tpm2_commit_space(chip, space, ordinal, buf, &len);
> + if (rc)
> + dev_err(&chip->dev, "tpm2_commit_space: error %d\n", rc);
>
> out:
> - if (chip->dev.parent)
> - pm_runtime_put_sync(chip->dev.parent);
> + rc = tpm_go_idle(chip, flags);
> + if (rc)
> + goto out;
>
> if (need_locality)
> - tpm_relinquish_locality(chip);
> + tpm_relinquish_locality(chip, flags);
>
> out_no_locality:
> if (chip->ops->clk_enable != NULL)
> diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
> index 4426649e431c..beb0a763016c 100644
> --- a/drivers/char/tpm/tpm.h
> +++ b/drivers/char/tpm/tpm.h
> @@ -511,9 +511,18 @@ extern const struct file_operations tpm_fops;
> extern const struct file_operations tpmrm_fops;
> extern struct idr dev_nums_idr;
>
> +/**
> + * enum tpm_transmit_flags
> + *
> + * @TPM_TRANSMIT_UNLOCKED: used to lock sequence of tpm_transmit calls.
> + * @__TPM_TRANSMIT_RAW: prevent recursive calls into setup steps
> + * (go idle, locality,..). Don't use directly.
> + * @TPM_TRANSMIT_NESTED: Use from nested tpm_transmit calls
> + */
> enum tpm_transmit_flags {
> - TPM_TRANSMIT_UNLOCKED = BIT(0),
> - TPM_TRANSMIT_RAW = BIT(1),
> + TPM_TRANSMIT_UNLOCKED = BIT(0),
> + __TPM_TRANSMIT_RAW = BIT(1),
NAK for the naming convention.
/Jarkko
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