[PATCH v12 6/8] doc: Add measured boot documentation

[Eddie James]

On 10/12/23 10:29, Simon Glass wrote:
> Hi Eddie,
>
> On Thu, 12 Oct 2023 at 08:08, Eddie James <eajames at linux.ibm.com> wrote:
>> Briefly describe the feature and specify the requirements.
>>
>> Signed-off-by: Eddie James <eajames at linux.ibm.com>
>> Reviewed-by: Simon Glass <sjg at chromium.org>
> This could use a bit more detail. What pieces are measured? What DT
> binding is used for the TPM? How is the info checked by the OS or
> whatever?


Sure, I'll add a little bit more. The DT binding is described in the 
requirements section.


>
>
>> ---
>>   doc/usage/index.rst         |  1 +
>>   doc/usage/measured_boot.rst | 23 +++++++++++++++++++++++
>>   2 files changed, 24 insertions(+)
>>   create mode 100644 doc/usage/measured_boot.rst
>>
>> diff --git a/doc/usage/index.rst b/doc/usage/index.rst
>> index fa702920fa..fb043a8923 100644
>> --- a/doc/usage/index.rst
>> +++ b/doc/usage/index.rst
>> @@ -14,6 +14,7 @@ Use U-Boot
>>      partitions
>>      cmdline
>>      semihosting
>> +   measured_boot
>>
>>   Shell commands
>>   --------------
>> diff --git a/doc/usage/measured_boot.rst b/doc/usage/measured_boot.rst
>> new file mode 100644
>> index 0000000000..8357b1f480
>> --- /dev/null
>> +++ b/doc/usage/measured_boot.rst
>> @@ -0,0 +1,23 @@
>> +.. SPDX-License-Identifier: GPL-2.0+
>> +
>> +Measured Boot
>> +=====================
>> +
>> +U-Boot can perform a measured boot, the process of hashing various components
>> +of the boot process, extending the results in the TPM and logging the
>> +component's measurement in memory for the operating system to consume.
>> +
>> +Requirements
>> +---------------------
>> +
>> +* A hardware TPM 2.0 supported by the U-Boot drivers
>> +* CONFIG_TPM=y
>> +* CONFIG_MEASURED_BOOT=y
>> +* Device-tree configuration of the TPM device to specify the memory area
>> +  for event logging. The TPM device node must either contain a phandle to
>> +  a reserved memory region or "linux,sml-base" and "linux,sml-size"
>> +  indicating the address and size of the memory region. An example can be
>> +  found in arch/sandbox/dts/test.dts
>> +* The operating system must also be configured to use the memory regions
>> +  specified in the U-Boot device-tree in order to make use of the event
>> +  log.
> Regards,
> Simon