Re: [PATCH 2/2] doc: Rework the gcc section to reflect general build instructions

[Heinrich Schuchardt]

Am 15. Februar 2024 23:00:32 MEZ schrieb Tom Rini <trini at konsulko.com>:
>On Thu, Feb 15, 2024 at 10:53:59PM +0100, Heinrich Schuchardt wrote:
>> 
>> 
>> Am 15. Februar 2024 22:28:24 MEZ schrieb Tom Rini <trini at konsulko.com>:
>> >On Thu, Feb 15, 2024 at 10:24:40PM +0100, Heinrich Schuchardt wrote:
>> >> 
>> >> 
>> >> Am 15. Februar 2024 22:10:25 MEZ schrieb Tom Rini <trini at konsulko.com>:
>> >> >The first big issue is that the "gcc" file talked a lot about the
>> >> >general build requirements as well, but was titled in a gcc-centric
>> >> >manner. Solve this by renaming the file to compile.rst and more fully
>> >> >reflecting that it is general build instructions. Next, add a section
>> >> >about the prebuilt toolchains that are recommended (as they are the ones
>> >> >we use in CI), and update a few places to reference these vendor-neutral
>> >> >tools.
>> >> >
>> >> >Next, we can include the reproducible builds section directly in the
>> >> >compile instructions rather than as a small standalone file.
>> >> >
>> >> >Finally, we update the sandbox document to reflect both the name change
>> >> >as well as what is specifically required to build sandbox.
>> >> >
>> >> >Signed-off-by: Tom Rini <trini at konsulko.com>
>> >> >---
>> >> >Cc: Heinrich Schuchardt <xypron.glpk at gmx.de>
>> >> >---
>> >> > doc/arch/sandbox/sandbox.rst       |  5 ++-
>> >> > doc/build/{gcc.rst => compile.rst} | 64 ++++++++++++++++++++++++++----
>> >> > doc/build/index.rst                |  3 +-
>> >> > doc/build/reproducible.rst         | 27 -------------
>> >> > 4 files changed, 61 insertions(+), 38 deletions(-)
>> >> > rename doc/build/{gcc.rst => compile.rst} (73%)
>> >> > delete mode 100644 doc/build/reproducible.rst
>> >> >
>> >> >diff --git a/doc/arch/sandbox/sandbox.rst b/doc/arch/sandbox/sandbox.rst
>> >> >index 5f8db126657f..f2ed5a25c115 100644
>> >> >--- a/doc/arch/sandbox/sandbox.rst
>> >> >+++ b/doc/arch/sandbox/sandbox.rst
>> >> >@@ -39,11 +39,12 @@ integers can only be built on 64-bit hosts.
>> >> > 
>> >> > Note that standalone/API support is not available at present.
>> >> > 
>> >> >-
>> >> > Prerequisites
>> >> > -------------
>> >> > 
>> >> >-Install the dependencies noted in :doc:`../../build/gcc`.
>> >> >+In addition to the normal dependencies shows in the :doc:`general build
>> >> >+instructions <../../build/compile>` to enable display support SDL2 libraries
>> >> >+need to be available.
>> >> > 
>> >> > 
>> >> > Basic Operation
>> >> >diff --git a/doc/build/gcc.rst b/doc/build/compile.rst
>> >> >similarity index 73%
>> >> >rename from doc/build/gcc.rst
>> >> >rename to doc/build/compile.rst
>> >> >index 3c6465772729..ef9c8545835a 100644
>> >> >--- a/doc/build/gcc.rst
>> >> >+++ b/doc/build/compile.rst
>> >> >@@ -1,11 +1,19 @@
>> >> >-Building with GCC
>> >> >-=================
>> >> >+Building U-Boot
>> >> >+===============
>> >> > 
>> >> > Dependencies
>> >> > ------------
>> >> > 
>> >> >-For building U-Boot you need a GCC compiler for your host platform. If you
>> >> >-are not building on the target platform you further need  a GCC cross compiler.
>> >> >+For building U-Boot you need the general build tools such as `make` and a C
>> >> >+compiler for your host platform. Next, if you are not building on the same
>> >> >+architecture as the target platform you further need a C cross compiler.
>> >> >+Furthermore, some target platforms require additional host tools to be present
>> >> >+and their package names may vary slightly dependinng on the naming scheme used
>> >> >+by a particular host OS.
>> >> >+
>> >> >+In general, GCC should be used for both the host and target C compiler. Using
>> >> >+:doc:`clang <clang>` is supported but please see the documented issues for it as
>> >> >+well.
>> >> > 
>> >> > Debian based
>> >> > ~~~~~~~~~~~~
>> >> >@@ -69,6 +77,17 @@ Depending on the build target further packages may be needed:
>> >> > * riscv64 S-mode targets: opensbi
>> >> > * some arm64 targets: arm-trusted-firmware
>> >> > 
>> >> >+Prebuilt
>> >> >+~~~~~~~~
>> >> >+
>> >> >+Another option, which the project uses for CI for example, is to use a prebuilt
>> >> >+toolchain. For the most part, we use the latest `kernel.org`_ prebuit binaries,
>> >> >+but there are a few architectures that require their own specific toolchains
>> >> >+still.
>> >> >+
>> >> >+In general, examples found within the documentation here refer to the tools
>> >> >+found here and exceptions will be noted where relevant.
>> >> >+
>> >> > Prerequisites
>> >> > -------------
>> >> > 
>> >> >@@ -112,11 +131,11 @@ command line or export it beforehand.
>> >> > 
>> >> >     CROSS_COMPILE=<compiler-prefix> make
>> >> > 
>> >> >-Assuming cross compiling on Debian for ARMv8 this would be
>> >> >+Assuming cross compiling for ARMv8 this would be
>> >> > 
>> >> > .. code-block:: bash
>> >> > 
>> >> >-    CROSS_COMPILE=aarch64-linux-gnu- make
>> >> >+    CROSS_COMPILE=aarch64-linux- make
>> >> 
>> >> GCC uses triples to specify the architecture. With the suggested change building will fail on many distros, e.g. in our CI image.
>> >> 
>> >> cf. https://gcc.gnu.org/install/specific.html#aarch64-x-x
>> >
>> >But this is what the kernel.org compiler is called, and for consistency
>> >we should reference the reference compiler in our docs. I'm wanting to
>> >follow up and change everyone to use consistent names.
>> >
>> 
>> Please, do not asume that Linux distros will change. 
>> 
>> Users will and should use the tools provided by their distros. Side loading foreign binaries is a secutity risc which should be avoided.
>> 
>> I cannot see what is inconsistent about sticking to triples.
>
>We need to be consistent within our docs, and we aren't today. And
>"-gnu" isn't a required suffix for aarch64 linux toolchains as not all
>distributions do that. I'd be open to wording suggesting that users
>install tools recommended by their vendors, but that still won't give us
>consistent names due to "aarch64-poky-linux-" being what other vendor
>tools will be.
>

On which operating systems will CROSS_COMPILE=aarch64-linux- work for the distro tools?

On which will CROSS_COMPILE=aarch64-linux-gnu- work?

Best regards

Heinrich