ccbb98880b
Signed-off-by: Michał Żygowski <michal.zygowski@3mdeb.com> Change-Id: I6f0963417c7c580f903922ac88c95569c8782bdb Reviewed-on: https://review.coreboot.org/c/coreboot/+/65702 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Krystian Hebel <krystian.hebel@3mdeb.com>
144 lines
6.1 KiB
Markdown
144 lines
6.1 KiB
Markdown
# CBFS SMBIOS hooks
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The document describes the coreboot options how to make CBFS files populate
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platform-unique SMBIOS data.
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## SMBIOS Serial Number
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The [DMTF SMBIOS specification] defines a field in the type 1 System
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Information and type 2 Baseboard Information called Serial Number. It
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is a null-terminated string field assumed to be unique per platform. Certain
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mainboard ports have SMBIOS hooks to generate the Serial Numbers from external
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data, e.g. Lenovo Thinkpads (see DRIVER_LENOVO_SERIALS). This driver aims to
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provide an option to populate the Serial Numbers from CBFS for boards that
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can't generate the it from any source.
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### Usage
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In the coreboot configuration menu (`make menuconfig`) go to `Generic Drivers`
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and select an option `Serial number in CBFS`. The Kconfig system will enable
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`DRIVERS_GENERIC_CBFS_SERIAL` and the relevant code parts will be compiled into
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coreboot image.
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After the coreboot build for your board completes, use the cbfstool to include
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the file containing the serial number:
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```shell
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./build/cbfstool build/coreboot.rom add -n serial_number -t raw -f /path/to/serial_file.txt
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```
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Where `serial_file.txt` is the unterminated string representation of the SMBIOS
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type 1 or type 2 Serial Number, e.g. `5Q4Q7Y1`. If you use vboot with 1 or 2 RW
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partitions you will have to specify the RW regions where the file is going to
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be added too. By default the RW CBFS partitions are truncated, so the files
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would probably not fit, one needs to expand them first.
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```shell
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./build/cbfstool build/coreboot.rom expand -r FW_MAIN_A
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./build/cbfstool build/coreboot.rom add -n serial_number -t raw \
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-f /path/to/serial_file.txt -r FW_MAIN_A
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./build/cbfstool build/coreboot.rom truncate -r FW_MAIN_A
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./build/cbfstool build/coreboot.rom expand -r FW_MAIN_B
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./build/cbfstool build/coreboot.rom add -n serial_number -t raw \
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-f /path/to/serial_file.txt -r FW_MAIN_B
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./build/cbfstool build/coreboot.rom truncate -r FW_MAIN_B
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```
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By default cbfstool adds files to COREBOOT region only, so when vboot is
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enabled and the platform is booting from RW partition, the file would not be
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picked up by the driver.
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One may retrieve the Serial Number from running system (if it exists) using one
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of the following commands:
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```shell
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# Type 1
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echo -n `sudo dmidecode -s system-serial-number` > serial_file.txt
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# OR Type 2
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echo -n `sudo dmidecode -s baseboard-serial-number` > serial_file.txt
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```
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Ensure the file does not end with whitespaces like LF and/or CR. The above
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commands will not add any whitespaces. The driver automatically terminates the
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Serial Number with the NULL character. If the CBFS file is not present, the
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driver will fall back to the string defined in `MAINBOARD_SERIAL_NUMBER` build
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option.
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Please note that this driver provides `smbios_mainboard_serial_number` hook
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overriding the default implementation which returns `MAINBOARD_SERIAL_NUMBER`
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build option. If you wish to populate only type 2 Serial Number field your
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board code needs to implement `smbios_system_serial_number`, otherwise the weak
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implementation of `smbios_system_serial_number` will call
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`smbios_mainboard_serial_number` from the `DRIVERS_GENERIC_CBFS_SERIAL`
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implementation overriding it. So selecting the `DRIVERS_GENERIC_CBFS_SERIAL`
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has a side-effect of populating both SMBIOS type 1 and type 2 Serial Numbers
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if the board does not implement its own `smbios_system_serial_number`.
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There is also SMBIOS type 3 Chassis Information Serial Number, but it is not
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populated by `DRIVERS_GENERIC_CBFS_SERIAL` nor by the default weak
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implementation (returns empty string). If you wish to populate type 3 Serial
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Number, your board code should override the default
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`smbios_chassis_serial_number` weak implementation.
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## SMBIOS System UUID
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The [DMTF SMBIOS specification] defines a field in the type 1 System
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Information Structure called System UUID. It is a 16 bytes value compliant with
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[RFC4122] and assumed to be unique per platform. Certain mainboard ports have
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SMBIOS hooks to generate the UUID from external data, e.g. Lenovo Thinkpads
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(see DRIVER_LENOVO_SERIALS). This driver aims to provide an option to populate
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the UUID from CBFS for boards that can't generate the UUID from any source.
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### Usage
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In the coreboot configuration menu (`make menuconfig`) go to `Generic Drivers`
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and select an option `System UUID in CBFS`. The Kconfig system will enable
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`DRIVERS_GENERIC_CBFS_UUID` and the relevant code parts will be compiled into
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coreboot image.
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After the coreboot build for your board completes, use the cbfstool to include
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the file containing the UUID:
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```shell
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./build/cbfstool build/coreboot.rom add -n system_uuid -t raw -f /path/to/uuid_file.txt
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```
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Where `uuid_file.txt` is the unterminated string representation of the SMBIOS
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type 1 UUID, e.g. `4c4c4544-0051-3410-8051-b5c04f375931`. If you use vboot with
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1 or 2 RW partitions you will have to specify the RW regions where the file is
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going to be added too. By default the RW CBFS partitions are truncated, so the
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files would probably not fit, one needs to expand them first.
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```shell
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./build/cbfstool build/coreboot.rom expand -r FW_MAIN_A
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./build/cbfstool build/coreboot.rom add -n system_uuid -t raw \
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-f /path/to/uuid_file.txt -r FW_MAIN_A
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./build/cbfstool build/coreboot.rom truncate -r FW_MAIN_A
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./build/cbfstool build/coreboot.rom expand -r FW_MAIN_B
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./build/cbfstool build/coreboot.rom add -n system_uuid -t raw \
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-f /path/to/uuid_file.txt -r FW_MAIN_B
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./build/cbfstool build/coreboot.rom truncate -r FW_MAIN_B
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```
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By default cbfstool adds files to COREBOOT region only, so when vboot is
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enabled and the platform is booting from RW partition, the file would not be
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picked up by the driver.
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One may retrieve the UUID from running system (if it exists) using the
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following command:
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```shell
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echo -n `sudo dmidecode -s system-uuid` > uuid_file.txt
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```
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The above command ensures the file does not end with whitespaces like LF and/or
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CR. The above command will not add any whitespaces. But the driver will handle
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situations where up to 2 additional bytes like CR and LF will be included in
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the file. Any more than that will make the driver fail to populate UUID in
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SMBIOS.
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[DMTF SMBIOS specification]: https://www.dmtf.org/standards/smbios
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[RFC4122]: https://www.ietf.org/rfc/rfc4122.txt
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