[PATCH 1/1] sandbox: allow cross-compiling sandbox

[Heinrich Schuchardt]

Am 9. Februar 2021 06:30:31 MEZ schrieb AKASHI Takahiro <takahiro.akashi at linaro.org>:
>On Mon, Feb 08, 2021 at 09:29:43PM -0700, Simon Glass wrote:
>> Hi Heinrich,
>> 
>> On Mon, 8 Feb 2021 at 15:06, Heinrich Schuchardt <xypron.glpk at gmx.de>
>wrote:
>> >
>> > UEFI test files like helloworld.efi require an architecture
>specific
>> > PE-COFF header.
>> 
>> architecture-specific
>> 
>> >
>> > For non-sandbox the PE-COFF header is chosen by the target
>architecture.
>> > For the sandbox we use the host architecture. This is not helpful
>for cross
>> > compiling. Allow specifying the target architecture of the sandbox
>via
>> > environment variable MK_ARCH, e.g.
>> 
>> What exactly is the target arch? Is the the one that sandbox is
>> running on, or something else?
>> 
>> >
>> >     make sandbox_defconfig NO_SDL=1
>> >     CROSS_COMPILE=aarch64-linux-gnu- NO_SDL=1 MK_ARCH=aarch64 make
>> >
>> > Signed-off-by: Heinrich Schuchardt <xypron.glpk at gmx.de>
>> > ---
>> >  Makefile             |  2 +-
>> >  doc/arch/sandbox.rst | 14 ++++++++++++++
>> >  2 files changed, 15 insertions(+), 1 deletion(-)
>> >
>> > diff --git a/Makefile b/Makefile
>> > index 23dd11f723..286e5148ae 100644
>> > --- a/Makefile
>> > +++ b/Makefile
>> > @@ -19,7 +19,7 @@ MAKEFLAGS += -rR --include-dir=$(CURDIR)
>> >
>> >  # Determine host architecture
>> >  include include/host_arch.h
>> > -MK_ARCH="${shell uname -m}"
>> > +MK_ARCH?="${shell uname -m}"
>> >  unexport HOST_ARCH
>> >  ifeq ("x86_64", $(MK_ARCH))
>> >    export HOST_ARCH=$(HOST_ARCH_X86_64)
>> > diff --git a/doc/arch/sandbox.rst b/doc/arch/sandbox.rst
>> > index 60ee1e0741..0dd9edc8cb 100644
>> > --- a/doc/arch/sandbox.rst
>> > +++ b/doc/arch/sandbox.rst
>> > @@ -33,6 +33,20 @@ integers can only be built on 64-bit hosts.
>> >
>> >  Note that standalone/API support is not available at present.
>> >
>> > +Cross compiling
>> > +---------------
>> > +
>> > +When cross compiling the U-Boot sandbox with CONFIG_EFI_LOADER=y
>the target
>> > +architecture must be specified using the MK_ARCH environment
>variable using one
>> > +of the values aarch64, armv7l, i386, riscv32, riscv64, x86_64,
>e.g.
>> 
>> OK, but what is the target architecture? I'm just not sure from your
>> comments what this actually means.
>
>I'm not quite sure if it is very useful to be able to cross-compile
>the sandbox application. But any way, it is not very convenient

Building the sandbox on ARMv7 is broken due to patch introduced in 2020. We get loads of warnings when building for 32bit.

We should integrate building the sandbox for different architectures into Gitlab CI.

>to always enforce users to explicitly specify "target" architecture.
>How about trying the following first?
>$(CC) -v | grep "Target: " | sed -e 's/-*$//'
>
>It will give us a hint about the architecture.
>("--print-multiarch" shows a similar triple, but this option won't
>work for some pre-built gcc, like aarch64 gcc from Arm.)

Did you check clang?

Is the output format specified? Will this be stable for compiler versions to come? Given the --print-multiarch failure probably not.

When compiling Linux you also have to supply CROSS_COMPILER and ARCH.

For me it is anyway a Gitlab CI thing. Nothing a user would typically use.

Best regards

Heinrich


>
>> Does MK mean make?
>
>I prefer another name for clarity.
>
>-Takahiro Akashi
>
>> 
>> > +
>> > +.. code-block:: bash
>> > +
>> > +    NO_SDL=1 make sandbox_defconfig
>> > +    CROSS_COMPILE=aarch64-linux-gnu- MK_ARCH=aarch64 NO_SDL=1 make
>> > +
>> > +NO_SDL=1 was chosen in the example to remove the dependency on the
>SDL library.
>> > +The graphical console will not be available.
>> >
>> >  Prerequisites
>> >  -------------
>> > --
>> > 2.30.0
>> >
>> 
>> Regards,
>> Simon