Messages in this thread | | | Date | Fri, 30 Jul 2021 16:12:52 -0700 | From | Fangrui Song <> | Subject | Re: [PATCH v5 3/3] Documentation/llvm: update CROSS_COMPILE inferencing |
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On 2021-07-30, Nick Desaulniers wrote: >As noted by Masahiro, document how we can generally infer CROSS_COMPILE >(and the more specific details about --target and --prefix) based on >ARCH. > >Suggested-by: Masahiro Yamada <masahiroy@kernel.org> >Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> >--- > Documentation/kbuild/llvm.rst | 17 +++++++++++++++++ > 1 file changed, 17 insertions(+) > >diff --git a/Documentation/kbuild/llvm.rst b/Documentation/kbuild/llvm.rst >index b18401d2ba82..4292f0686316 100644 >--- a/Documentation/kbuild/llvm.rst >+++ b/Documentation/kbuild/llvm.rst >@@ -63,6 +63,23 @@ They can be enabled individually. The full list of the parameters: :: > Currently, the integrated assembler is disabled by default. You can pass > ``LLVM_IAS=1`` to enable it. > >+Omitting CROSS_COMPILE >+---------------------- >+ >+As explained above, ``CROSS_COMPILE`` is used to set ``--target=<triple>``. >+ >+Unless ``LLVM_IAS=1`` is specified, ``CROSS_COMPILE`` is also used to derive >+``--prefix=<path>`` to search for the GNU assembler.
and the GNU linker.
Reviewed-by: Fangrui Song <maskray@google.com>
>+If ``CROSS_COMPILE`` is not specified, the ``--target=<triple>`` is inferred >+from ``ARCH``. >+ >+That means if you use only LLVM tools, ``CROSS_COMPILE`` becomes unnecessary. >+ >+For example, to cross-compile the arm64 kernel:: >+ >+ ARCH=arm64 make LLVM=1 LLVM_IAS=1
Is ARCH=arm64 make LLVM=1 LLVM_IAS=1
preferred over
make ARCH=arm64 LLVM=1 LLVM_IAS=1
?
> Supported Architectures > ----------------------- > >-- >2.32.0.554.ge1b32706d8-goog >
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