[PATCH v2 3/6] scripts/Makefile.lib: Embed capsule public key in platform's dtb

[Ilias Apalodimas]

Hi Sughosh

On Thu, 17 Aug 2023 at 08:49, Sughosh Ganu <sughosh.ganu at linaro.org> wrote:
>
> The EFI capsule authentication logic in u-boot expects the public key
> in the form of an EFI Signature List(ESL) to be provided as part of
> the platform's dtb. Currently, the embedding of the ESL file into the
> dtb needs to be done manually.
>
> Add a target for generating a dtsi file which contains the signature
> node with the ESL file included as a property under the signature
> node. Include the dtsi file in the dtb. This brings the embedding of
> the ESL in the dtb into the U-Boot build flow.
>
> The path to the ESL file is specified through the
> CONFIG_EFI_CAPSULE_ESL_FILE symbol.
>
> Signed-off-by: Sughosh Ganu <sughosh.ganu at linaro.org>
> ---
> Changes since V1:
> * Put only the setting of dtsi_include_list under the ifdef, moving
>   the rest of the logic out of the ifdef.
>
>  lib/efi_loader/Kconfig             |  8 ++++++++
>  lib/efi_loader/capsule_esl.dtsi.in | 11 +++++++++++
>  scripts/Makefile.lib               | 15 +++++++++++++++
>  3 files changed, 34 insertions(+)
>  create mode 100644 lib/efi_loader/capsule_esl.dtsi.in
>
> diff --git a/lib/efi_loader/Kconfig b/lib/efi_loader/Kconfig
> index 9989e3f384..d20aaab6db 100644
> --- a/lib/efi_loader/Kconfig
> +++ b/lib/efi_loader/Kconfig
> @@ -272,6 +272,14 @@ config EFI_CAPSULE_MAX
>           Select the max capsule index value used for capsule report
>           variables. This value is used to create CapsuleMax variable.
>
> +config EFI_CAPSULE_ESL_FILE
> +       string "Path to the EFI Signature List File"
> +       depends on EFI_CAPSULE_AUTHENTICATE
> +       help
> +         Provides the path to the EFI Signature List file which will
> +         be embedded in the platform's device tree and used for
> +         capsule authentication at the time of capsule update.
> +
>  config EFI_DEVICE_PATH_TO_TEXT
>         bool "Device path to text protocol"
>         default y
> diff --git a/lib/efi_loader/capsule_esl.dtsi.in b/lib/efi_loader/capsule_esl.dtsi.in
> new file mode 100644
> index 0000000000..61a9f2b25e
> --- /dev/null
> +++ b/lib/efi_loader/capsule_esl.dtsi.in
> @@ -0,0 +1,11 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/**
> + * Devicetree file with the public key EFI Signature List(ESL)
> + * node. This file is used to generate the dtsi file to be
> + * included into the DTB.
> +*/
> +/ {
> +       signature {
> +               capsule-key = /incbin/("ESL_BIN_FILE");
> +       };
> +};
> diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
> index 8c5e25c31c..3cec46bb15 100644
> --- a/scripts/Makefile.lib
> +++ b/scripts/Makefile.lib
> @@ -334,6 +334,21 @@ cmd_dtc = mkdir -p $(dir ${dtc-tmp}) ; \
>                 ; \
>         sed "s:$(pre-tmp):$(<):" $(depfile).pre.tmp $(depfile).dtc.tmp > $(depfile)
>
> +quiet_cmd_capsule_esl_gen = CAPSULE_ESL_GEN $@
> +cmd_capsule_esl_gen = \
> +       $(shell sed "s:ESL_BIN_FILE:$(capsule_esl_path):" $(capsule_esl_input_file) > $@)
> +
> +$(obj)/.capsule_esl.dtsi:
> +       $(call cmd_capsule_esl_gen)
> +
> +capsule_esl_input_file=$(srctree)/lib/efi_loader/capsule_esl.dtsi.in
> +capsule_esl_dtsi = .capsule_esl.dtsi

Any reason why cant reuse $capsule_esl_dtsi in capsule_esl_input_file?

Thanks
/Ilias
> +capsule_esl_path=$(abspath $(srctree)/$(subst $(quote),,$(CONFIG_EFI_CAPSULE_ESL_FILE)))
> +
> +ifdef CONFIG_EFI_CAPSULE_AUTHENTICATE
> +dtsi_include_list += $(capsule_esl_dtsi)
> +endif
> +
>  dtsi_include_list_deps = $(addprefix $(obj)/,$(subst $(quote),,$(dtsi_include_list)))
>
>  $(obj)/%.dtb: $(src)/%.dts $(DTC) $(dtsi_include_list_deps) FORCE
> --
> 2.34.1
>