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

[Jeremiah Mahler <jmmahler@gmail.com>]

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@linux.intel.com>
> Reviewed-by: Jason Gunthorpe <jason.gunthorpe@obsidianresearch.com>
> Tested-by: Mimi Zohar <zohar@linux.vnet.ibm.com> (on TPM 1.2)
> Tested-by: Chris J Arges <chris.j.arges@canonical.com>
> Tested-by: Colin Ian King <colin.king@canonical.com>
> ---
>  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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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.

-- 
- Jeremiah Mahler