Re: [PATCH] tpm: enable PPI for TPM 2.0

[Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>]

On Thu, Apr 16, 2015 at 06:54:39PM +0300, Jarkko Sakkinen wrote:
> Added PPI interface to the character device sysfs directory accessible
> both for 1.x and 2.0 devices.
> 
> In order to maintain backwards compatibility when using 1.x devices,
> symlink is created from the pdev to the PPI directory. For this reason
> we need to export kernfs_create_link() and kernfs_remove_by_name_ns().
> 
> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> Reviewed-by: Jason Gunthorpe <jason.gunthorpe@obsidianresearch.com>
> ---
>  drivers/char/tpm/tpm-chip.c | 28 ++++++++++++++++++++--------
>  drivers/char/tpm/tpm.h      | 14 +++++---------
>  drivers/char/tpm/tpm_ppi.c  | 34 +++++++++++-----------------------
>  fs/kernfs/dir.c             |  1 +
>  fs/kernfs/symlink.c         |  1 +
>  5 files changed, 38 insertions(+), 40 deletions(-)
> 
> diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
> index 283f00a..34930ef 100644
> --- a/drivers/char/tpm/tpm-chip.c
> +++ b/drivers/char/tpm/tpm-chip.c
> @@ -26,6 +26,7 @@
>  #include <linux/spinlock.h>
>  #include <linux/freezer.h>
>  #include <linux/major.h>
> +#include <linux/kernfs.h>
>  #include "tpm.h"
>  #include "tpm_eventlog.h"
>  
> @@ -119,6 +120,9 @@ 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);
> @@ -181,12 +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;
> @@ -200,8 +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);
>  }
>  
> @@ -218,16 +214,29 @@ static void tpm1_chip_unregister(struct tpm_chip *chip)
>   */
>  int tpm_chip_register(struct tpm_chip *chip)
>  {
> +	struct kernfs_node *target;
> +	struct kernfs_node *link;
>  	int rc;
>  
>  	rc = tpm1_chip_register(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)) {
> +		target = kernfs_find_and_get(chip->dev.kobj.sd, "ppi");

Check that valid node was returned.

> +		link = kernfs_create_link(chip->pdev->kobj.sd, "ppi", target);
> +		if (IS_ERR(link)) {
> +			rc = PTR_ERR(link);
> +			goto out_err;
> +		}

Oops, kernfs_put() missing from the patch.


> +	}
> +
>  	/* Make the chip available. */
>  	spin_lock(&driver_lock);
>  	list_add_rcu(&chip->list, &tpm_chip_list);
> @@ -262,6 +271,9 @@ void tpm_chip_unregister(struct tpm_chip *chip)
>  	spin_unlock(&driver_lock);
>  	synchronize_rcu();
>  
> +	if (!(chip->flags & TPM_CHIP_FLAG_TPM2))
> +		kernfs_remove_by_name(chip->pdev->kobj.sd, "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 f8319a0..bbb1fae 100644
> --- a/drivers/char/tpm/tpm.h
> +++ b/drivers/char/tpm/tpm.h
> @@ -175,6 +175,8 @@ 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 */
> @@ -182,7 +184,7 @@ struct tpm_chip {
>  	struct list_head list;
>  };
>  
> -#define to_tpm_chip(n) container_of(n, struct tpm_chip, vendor)
> +#define to_tpm_chip(n) container_of(dev, struct tpm_chip, dev)
>  
>  static inline void tpm_chip_put(struct tpm_chip *chip)
>  {
> @@ -412,15 +414,9 @@ 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;
>  }
> diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
> index 6acc964..749cea3 100644
> --- a/fs/kernfs/dir.c
> +++ b/fs/kernfs/dir.c
> @@ -1225,6 +1225,7 @@ int kernfs_remove_by_name_ns(struct kernfs_node *parent, const char *name,
>  	else
>  		return -ENOENT;
>  }
> +EXPORT_SYMBOL_GPL(kernfs_remove_by_name_ns);
>  
>  /**
>   * kernfs_rename_ns - move and rename a kernfs_node
> diff --git a/fs/kernfs/symlink.c b/fs/kernfs/symlink.c
> index 8a19889..fd70d1d 100644
> --- a/fs/kernfs/symlink.c
> +++ b/fs/kernfs/symlink.c
> @@ -45,6 +45,7 @@ struct kernfs_node *kernfs_create_link(struct kernfs_node *parent,
>  	kernfs_put(kn);
>  	return ERR_PTR(error);
>  }
> +EXPORT_SYMBOL_GPL(kernfs_create_link);
>  
>  static int kernfs_get_target_path(struct kernfs_node *parent,
>  				  struct kernfs_node *target, char *path)
> -- 
> 2.1.4
> 

Other: remove TPM_CHIP_FLAG_PPI from tpm.h.

/Jarkko