[PATCH v6] tpm: separate cmd_ready/go_idle from runtime_pm

[Winkler, Tomas]

> 
> 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 at vger.kernel.org
> > Fixes: 888d867df441 (tpm: cmd_ready command can be issued only after
> > granting locality)
> > Signed-off-by: Tomas Winkler <tomas.winkler at intel.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.

What do you suggest
Tomas

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