Merge tag 'for-linus-5.15-1' of git://github.com/cminyard/linux-ipmi

[linux-2.6-microblaze.git] / Documentation / kbuild / llvm.rst

diff --git a/Documentation/kbuild/llvm.rst b/Documentation/kbuild/llvm.rst
index 683f8b7..d326168 100644 (file)
--- a/Documentation/kbuild/llvm.rst
+++ b/Documentation/kbuild/llvm.rst
@@ -38,7 +38,7 @@ Cross Compiling
 A single Clang compiler binary will typically contain all supported backends,
 which can help simplify cross compiling. ::
 
-       ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- make CC=clang
+       make ARCH=arm64 CC=clang CROSS_COMPILE=aarch64-linux-gnu-
 
 ``CROSS_COMPILE`` is not used to prefix the Clang compiler binary, instead
 ``CROSS_COMPILE`` is used to set a command line flag: ``--target=<triple>``. For
@@ -60,8 +60,27 @@ They can be enabled individually. The full list of the parameters: ::
          OBJCOPY=llvm-objcopy OBJDUMP=llvm-objdump READELF=llvm-readelf \
          HOSTCC=clang HOSTCXX=clang++ HOSTAR=llvm-ar HOSTLD=ld.lld
 
-Currently, the integrated assembler is disabled by default. You can pass
-``LLVM_IAS=1`` to enable it.
+The integrated assembler is enabled by default. You can pass ``LLVM_IAS=0`` to
+disable it.
+
+Omitting CROSS_COMPILE
+----------------------
+
+As explained above, ``CROSS_COMPILE`` is used to set ``--target=<triple>``.
+
+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::
+
+       make ARCH=arm64 LLVM=1
+
+If ``LLVM_IAS=0`` is specified, ``CROSS_COMPILE`` is also used to derive
+``--prefix=<path>`` to search for the GNU assembler and linker. ::
+
+       make ARCH=arm64 LLVM=1 LLVM_IAS=0 CROSS_COMPILE=aarch64-linux-gnu-
 
 Supported Architectures
 -----------------------