e2fb992d82
TPM2 can return TPM2_RC_RETRY to any command and when it does we get
unexpected failures inside the kernel that surprise users (this is
mostly observed in the trusted key handling code). The UEFI 2.6 spec
has advice on how to handle this:
The firmware SHALL not return TPM2_RC_RETRY prior to the completion
of the call to ExitBootServices().
Implementer’s Note: the implementation of this function should check
the return value in the TPM response and, if it is TPM2_RC_RETRY,
resend the command. The implementation may abort if a sufficient
number of retries has been done.
So we follow that advice in our tpm_transmit() code using
TPM2_DURATION_SHORT as the initial wait duration and
TPM2_DURATION_LONG as the maximum wait time. This should fix all the
in-kernel use cases and also means that user space TSS implementations
don't have to have their own retry handling.
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: stable@vger.kernel.org
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.