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

[Sughosh Ganu]

hi Ilias,

On Thu, 17 Aug 2023 at 17:29, Ilias Apalodimas
<ilias.apalodimas at linaro.org> wrote:
>
> 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?

Are you suggesting having a lib/efi_loader/.capsule_esl.dtsi as the
input file? I thought having that distinction in the names between the
input file and the generated file keeps things a bit more clear.

-sughosh

>
> 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
> >