On Wed, Oct 22, 2014 at 07:23:56PM +0300, Jarkko Sakkinen wrote:
> Traversal of the ACPI device tree was not done right. It should lookup
> PPI only under the ACPI device that it is associated. Otherwise, it could
> match to a wrong PPI interface if there are two TPM devices in the device
> tree.
>
> Removed global ACPI handle and version string from tpm_ppi.c as this
> is racy. Instead they should be associated with the chip.
>
> Moved code just a tiny bit towards two-phase allocation to implement
> fix for the PPI race conditions.
Not this version..
> Added missing copyright platter to tpm_ppi.c.
>
> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
Reviewed-by: Jason Gunthorpe <jgunthorpe@xxxxxxxxxxxxxxxxxxxx>
I like this one the most of the three I've seen :)
Did you also look in tpm_acpi.c to see if it needs to use
acpi_dev_handle somehow too?
> + union acpi_object *obj;
> + struct kobject *parent = &chip->dev->kobj;
Nit, this variable is only used once, it would be clearer to inline
> + /* Cache PPI version string. */
> + obj = acpi_evaluate_dsm_typed(chip->acpi_dev_handle, tpm_ppi_uuid,
> + TPM_PPI_REVISION_ID, TPM_PPI_FN_VERSION,
> + NULL, ACPI_TYPE_STRING);
> + if (obj) {
> + strlcpy(chip->ppi_version, obj->string.pointer,
> + PPI_VERSION_LEN + 1);
> + ACPI_FREE(obj);
> + } else
> + return -ENOMEM;
> +
> + return chip->acpi_dev_handle ?
> + sysfs_create_group(parent, &ppi_attr_grp) : 0;
The above sequence can just be:
if (!obj)
return -ENOMEM;
strlcpy(chip->ppi_version, obj->string.pointer, sizeof(chip->ppi_version));
ACPI_FREE(obj);
return sysfs_create_group(&chip->dev->kobj, &ppi_attr_grp);
Which is more idiomatic. Also remove TPM_PPI_VERSION_LEN, sizeof is better.
I know nothing about acpi, but is ENOMEM the right code? I would think
acpi_evalute_dsm_typed would also fail if tpm_ppi_uuid is not found??
> + return chip->acpi_dev_handle ?
> + sysfs_create_group(parent, &ppi_attr_grp) : 0;
dev_handle is already checked to be non 0
> +void tpm_remove_ppi(struct tpm_chip *chip)
> + struct kobject *parent = &chip->dev->kobj;
Also used only once
Jason
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