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authorBehan Webster <behanw@converseincode.com>2017-04-21 21:20:01 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-11-27 18:07:57 +0300
commitcbb5fc70e499b794741f431443874be6977ac539 (patch)
tree55e1ec6fdeba61d0f2e5a0001b0b8313e3bb031a
parentc37215a94f5ee89ec10575ea28ec20f1e89f3015 (diff)
downloadlinux-cbb5fc70e499b794741f431443874be6977ac539.tar.xz
kbuild: Add better clang cross build support
commit 785f11aa595bc3d4e74096cbd598ada54ecc0d81 upstream. Add cross target to CC if using clang. Also add custom gcc toolchain path for fallback gcc tools. Clang will fallback to using things like ld, as, and libgcc if (respectively) one of the llvm linkers isn't available, the integrated assembler is turned off, or an appropriately cross-compiled version of compiler-rt isn't available. To this end, you can specify the path to this fallback gcc toolchain with GCC_TOOLCHAIN. Signed-off-by: Behan Webster <behanw@converseincode.com> Reviewed-by: Jan-Simon Möller <dl9pf@gmx.de> Reviewed-by: Mark Charlebois <charlebm@gmail.com> Signed-off-by: Greg Hackmann <ghackmann@google.com> Signed-off-by: Matthias Kaehlcke <mka@chromium.org> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--Makefile9
1 files changed, 9 insertions, 0 deletions
diff --git a/Makefile b/Makefile
index 9382e7e4e750..7fedb079d7a7 100644
--- a/Makefile
+++ b/Makefile
@@ -698,6 +698,15 @@ endif
KBUILD_CFLAGS += $(stackp-flag)
ifeq ($(cc-name),clang)
+ifneq ($(CROSS_COMPILE),)
+CLANG_TARGET := -target $(notdir $(CROSS_COMPILE:%-=%))
+GCC_TOOLCHAIN := $(realpath $(dir $(shell which $(LD)))/..)
+endif
+ifneq ($(GCC_TOOLCHAIN),)
+CLANG_GCC_TC := -gcc-toolchain $(GCC_TOOLCHAIN)
+endif
+KBUILD_CFLAGS += $(CLANG_TARGET) $(CLANG_GCC_TC)
+KBUILD_AFLAGS += $(CLANG_TARGET) $(CLANG_GCC_TC)
KBUILD_CPPFLAGS += $(call cc-option,-Qunused-arguments,)
KBUILD_CPPFLAGS += $(call cc-option,-Wno-unknown-warning-option,)
KBUILD_CFLAGS += $(call cc-disable-warning, unused-variable)