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

From: Jeremiah Mahler
Date: Wed Nov 04 2015 - 13:17:15 EST


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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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
--
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