Re: [BUG, bisect, PATCH 04/10] tpm: move the PPI attributes to character device directory.

[Jarkko Sakkinen]

On Wed, Nov 04, 2015 at 10:17:05AM -0800, Jeremiah Mahler wrote:
> Jarkko, all,
> 
> On Fri, Oct 16, 2015 at 09:40:23PM +0300, Jarkko Sakkinen wrote:
> > Moved PPI attributes to the character device directory. This aligns with
> > the sysfs guidelines and makes them race free because they are created
> > atomically with the character device as part of device_register().The
> > character device and the sysfs attributes appear at the same time to the
> > user space.
> > 
> > As part of this change we enable PPI attributes also for TPM 2.0
> > devices. In order to retain backwards compatibility with TPM 1.x
> > devices, a symlink is created to the platform device directory.
> > 
> > Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
> > Reviewed-by: Jason Gunthorpe <jason.gunthorpe@xxxxxxxxxxxxxxxxxxxx>
> > Tested-by: Mimi Zohar <zohar@xxxxxxxxxxxxxxxxxx> (on TPM 1.2)
> > Tested-by: Chris J Arges <chris.j.arges@xxxxxxxxxxxxx>
> > Tested-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
> > ---
> >  drivers/char/tpm/tpm-chip.c | 24 ++++++++++++++++--------
> >  drivers/char/tpm/tpm.h      | 17 ++++++-----------
> >  drivers/char/tpm/tpm_ppi.c  | 34 +++++++++++-----------------------
> >  3 files changed, 33 insertions(+), 42 deletions(-)
> > 
> > diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
> > index 1082d4b..f26b0ae 100644
> > --- a/drivers/char/tpm/tpm-chip.c
> > +++ b/drivers/char/tpm/tpm-chip.c
> > @@ -119,6 +119,9 @@ struct tpm_chip *tpmm_chip_alloc(struct device *dev,
> >  	chip->dev.class = tpm_class;
> >  	chip->dev.release = tpm_dev_release;
> >  	chip->dev.parent = chip->pdev;
> > +#ifdef CONFIG_ACPI
> > +	chip->dev.groups = chip->groups;
> > +#endif
> >  
> >  	if (chip->dev_num == 0)
> >  		chip->dev.devt = MKDEV(MISC_MAJOR, TPM_MINOR);
> > @@ -182,12 +185,6 @@ static int tpm1_chip_register(struct tpm_chip *chip)
> >  	if (rc)
> >  		return rc;
> >  
> > -	rc = tpm_add_ppi(chip);
> > -	if (rc) {
> > -		tpm_sysfs_del_device(chip);
> > -		return rc;
> > -	}
> > -
> >  	chip->bios_dir = tpm_bios_log_setup(chip->devname);
> >  
> >  	return 0;
> > @@ -201,8 +198,6 @@ static void tpm1_chip_unregister(struct tpm_chip *chip)
> >  	if (chip->bios_dir)
> >  		tpm_bios_log_teardown(chip->bios_dir);
> >  
> > -	tpm_remove_ppi(chip);
> > -
> >  	tpm_sysfs_del_device(chip);
> >  }
> >  
> > @@ -225,10 +220,20 @@ int tpm_chip_register(struct tpm_chip *chip)
> >  	if (rc)
> >  		return rc;
> >  
> > +	tpm_add_ppi(chip);
> > +
> >  	rc = tpm_dev_add_device(chip);
> >  	if (rc)
> >  		goto out_err;
> >  
> > +	if (!(chip->flags & TPM_CHIP_FLAG_TPM2)) {
> > +		rc = __compat_only_sysfs_link_entry_to_kobj(&chip->pdev->kobj,
> > +							    &chip->dev.kobj,
> > +							    "ppi");
> > +		if (rc)
> > +			goto out_err;
> > +	}
> > +
> >  	/* Make the chip available. */
> >  	spin_lock(&driver_lock);
> >  	list_add_rcu(&chip->list, &tpm_chip_list);
> > @@ -263,6 +268,9 @@ void tpm_chip_unregister(struct tpm_chip *chip)
> >  	spin_unlock(&driver_lock);
> >  	synchronize_rcu();
> >  
> > +	if (!(chip->flags & TPM_CHIP_FLAG_TPM2))
> > +		sysfs_remove_link(&chip->pdev->kobj, "ppi");
> > +
> >  	tpm1_chip_unregister(chip);
> >  	tpm_dev_del_device(chip);
> >  }
> > diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
> > index 39be5ac..36ceb71 100644
> > --- a/drivers/char/tpm/tpm.h
> > +++ b/drivers/char/tpm/tpm.h
> > @@ -158,8 +158,7 @@ struct tpm_vendor_specific {
> >  
> >  enum tpm_chip_flags {
> >  	TPM_CHIP_FLAG_REGISTERED	= BIT(0),
> > -	TPM_CHIP_FLAG_PPI		= BIT(1),
> > -	TPM_CHIP_FLAG_TPM2		= BIT(2),
> > +	TPM_CHIP_FLAG_TPM2		= BIT(1),
> >  };
> >  
> >  struct tpm_chip {
> > @@ -182,6 +181,8 @@ struct tpm_chip {
> >  	struct dentry **bios_dir;
> >  
> >  #ifdef CONFIG_ACPI
> > +	const struct attribute_group *groups[2];
> > +	unsigned int groups_cnt;
> >  	acpi_handle acpi_dev_handle;
> >  	char ppi_version[TPM_PPI_VERSION_LEN + 1];
> >  #endif /* CONFIG_ACPI */
> > @@ -189,7 +190,7 @@ struct tpm_chip {
> >  	struct list_head list;
> >  };
> >  
> > -#define to_tpm_chip(n) container_of(n, struct tpm_chip, vendor)
> > +#define to_tpm_chip(d) container_of(d, struct tpm_chip, dev)
> >  
> >  static inline void tpm_chip_put(struct tpm_chip *chip)
> >  {
> > @@ -419,15 +420,9 @@ void tpm_sysfs_del_device(struct tpm_chip *chip);
> >  int tpm_pcr_read_dev(struct tpm_chip *chip, int pcr_idx, u8 *res_buf);
> >  
> >  #ifdef CONFIG_ACPI
> > -extern int tpm_add_ppi(struct tpm_chip *chip);
> > -extern void tpm_remove_ppi(struct tpm_chip *chip);
> > +extern void tpm_add_ppi(struct tpm_chip *chip);
> >  #else
> > -static inline int tpm_add_ppi(struct tpm_chip *chip)
> > -{
> > -	return 0;
> > -}
> > -
> > -static inline void tpm_remove_ppi(struct tpm_chip *chip)
> > +static inline void tpm_add_ppi(struct tpm_chip *chip)
> >  {
> >  }
> >  #endif
> > diff --git a/drivers/char/tpm/tpm_ppi.c b/drivers/char/tpm/tpm_ppi.c
> > index 6ca9b5d..692a2c6 100644
> > --- a/drivers/char/tpm/tpm_ppi.c
> > +++ b/drivers/char/tpm/tpm_ppi.c
> > @@ -53,7 +53,7 @@ tpm_eval_dsm(acpi_handle ppi_handle, int func, acpi_object_type type,
> >  static ssize_t tpm_show_ppi_version(struct device *dev,
> >  				    struct device_attribute *attr, char *buf)
> >  {
> > -	struct tpm_chip *chip = dev_get_drvdata(dev);
> > +	struct tpm_chip *chip = to_tpm_chip(dev);
> >  
> >  	return scnprintf(buf, PAGE_SIZE, "%s\n", chip->ppi_version);
> >  }
> > @@ -63,7 +63,7 @@ static ssize_t tpm_show_ppi_request(struct device *dev,
> >  {
> >  	ssize_t size = -EINVAL;
> >  	union acpi_object *obj;
> > -	struct tpm_chip *chip = dev_get_drvdata(dev);
> > +	struct tpm_chip *chip = to_tpm_chip(dev);
> >  
> >  	obj = tpm_eval_dsm(chip->acpi_dev_handle, TPM_PPI_FN_GETREQ,
> >  			   ACPI_TYPE_PACKAGE, NULL);
> > @@ -100,7 +100,7 @@ static ssize_t tpm_store_ppi_request(struct device *dev,
> >  	int func = TPM_PPI_FN_SUBREQ;
> >  	union acpi_object *obj, tmp;
> >  	union acpi_object argv4 = ACPI_INIT_DSM_ARGV4(1, &tmp);
> > -	struct tpm_chip *chip = dev_get_drvdata(dev);
> > +	struct tpm_chip *chip = to_tpm_chip(dev);
> >  
> >  	/*
> >  	 * the function to submit TPM operation request to pre-os environment
> > @@ -156,7 +156,7 @@ static ssize_t tpm_show_ppi_transition_action(struct device *dev,
> >  		.buffer.length = 0,
> >  		.buffer.pointer = NULL
> >  	};
> > -	struct tpm_chip *chip = dev_get_drvdata(dev);
> > +	struct tpm_chip *chip = to_tpm_chip(dev);
> >  
> >  	static char *info[] = {
> >  		"None",
> > @@ -197,7 +197,7 @@ static ssize_t tpm_show_ppi_response(struct device *dev,
> >  	acpi_status status = -EINVAL;
> >  	union acpi_object *obj, *ret_obj;
> >  	u64 req, res;
> > -	struct tpm_chip *chip = dev_get_drvdata(dev);
> > +	struct tpm_chip *chip = to_tpm_chip(dev);
> >  
> >  	obj = tpm_eval_dsm(chip->acpi_dev_handle, TPM_PPI_FN_GETRSP,
> >  			   ACPI_TYPE_PACKAGE, NULL);
> > @@ -296,7 +296,7 @@ static ssize_t tpm_show_ppi_tcg_operations(struct device *dev,
> >  					   struct device_attribute *attr,
> >  					   char *buf)
> >  {
> > -	struct tpm_chip *chip = dev_get_drvdata(dev);
> > +	struct tpm_chip *chip = to_tpm_chip(dev);
> >  
> >  	return show_ppi_operations(chip->acpi_dev_handle, buf, 0,
> >  				   PPI_TPM_REQ_MAX);
> > @@ -306,7 +306,7 @@ static ssize_t tpm_show_ppi_vs_operations(struct device *dev,
> >  					  struct device_attribute *attr,
> >  					  char *buf)
> >  {
> > -	struct tpm_chip *chip = dev_get_drvdata(dev);
> > +	struct tpm_chip *chip = to_tpm_chip(dev);
> >  
> >  	return show_ppi_operations(chip->acpi_dev_handle, buf, PPI_VS_REQ_START,
> >  				   PPI_VS_REQ_END);
> > @@ -334,17 +334,16 @@ static struct attribute_group ppi_attr_grp = {
> >  	.attrs = ppi_attrs
> >  };
> >  
> > -int tpm_add_ppi(struct tpm_chip *chip)
> > +void tpm_add_ppi(struct tpm_chip *chip)
> >  {
> >  	union acpi_object *obj;
> > -	int rc;
> >  
> >  	if (!chip->acpi_dev_handle)
> > -		return 0;
> > +		return;
> >  
> >  	if (!acpi_check_dsm(chip->acpi_dev_handle, tpm_ppi_uuid,
> >  			    TPM_PPI_REVISION_ID, 1 << TPM_PPI_FN_VERSION))
> > -		return 0;
> > +		return;
> >  
> >  	/* Cache PPI version string. */
> >  	obj = acpi_evaluate_dsm_typed(chip->acpi_dev_handle, tpm_ppi_uuid,
> > @@ -356,16 +355,5 @@ int tpm_add_ppi(struct tpm_chip *chip)
> >  		ACPI_FREE(obj);
> >  	}
> >  
> > -	rc = sysfs_create_group(&chip->pdev->kobj, &ppi_attr_grp);
> > -
> > -	if (!rc)
> > -		chip->flags |= TPM_CHIP_FLAG_PPI;
> > -
> > -	return rc;
> > -}
> > -
> > -void tpm_remove_ppi(struct tpm_chip *chip)
> > -{
> > -	if (chip->flags & TPM_CHIP_FLAG_PPI)
> > -		sysfs_remove_group(&chip->pdev->kobj, &ppi_attr_grp);
> > +	chip->groups[chip->groups_cnt++] = &ppi_attr_grp;
> >  }
> > -- 
> > 2.5.0
> > 
> > --
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> > Please read the FAQ at  http://www.tux.org/lkml/
> 
> The commit for this patch (9b774d5cf2db4) present in the latest
> linux-next (20151101+) breaks suspend/resume on an Acer C720 Chromebook.
> The computer will successfully suspend but when a resume is attempted
> a blank screen is displayed for a few seconds and then it reboots.

I think I have this same model at home (have to check). If it is, I can
try to reproduce it today when I get back to home.

What kind of environment are you running?
Are you able to acquire kernel logs?

> -- 
> - Jeremiah Mahler

/Jarkko
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