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@xxxxxxxxxx> Signed-off-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx> --- 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@xxxxxxxxxx>
+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
