From 1f2239c47e4a8ffb4c34b5120d71cbca6f0b4825 Mon Sep 17 00:00:00 2001
From: Jose Quaresma <jose.quaresma@foundries.io>
Date: Tue, 9 May 2023 10:07:43 +0000
Subject: [PATCH] fixup! base: linux-lmp: build with clang

---
 .../recipes-kernel/linux/linux-lmp-clang.inc  | 22 +++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/meta-lmp-base/recipes-kernel/linux/linux-lmp-clang.inc b/meta-lmp-base/recipes-kernel/linux/linux-lmp-clang.inc
index 03064924f4..930cb26d40 100644
--- a/meta-lmp-base/recipes-kernel/linux/linux-lmp-clang.inc
+++ b/meta-lmp-base/recipes-kernel/linux/linux-lmp-clang.inc
@@ -3,10 +3,28 @@
 TOOLCHAIN:forcevariable = "clang"
 
 DEPENDS:append:toolchain-clang = " clang-cross-${TARGET_ARCH}"
-KERNEL_CC:toolchain-clang = "${CCACHE}clang ${HOST_CC_KERNEL_ARCH} ${DEBUG_PREFIX_MAP} -fdebug-prefix-map=${STAGING_KERNEL_DIR}=${KERNEL_SRC_PATH}"
+KERNEL_CC:toolchain-clang = "${CCACHE}clang ${HOST_CC_KERNEL_ARCH} -fuse-ld=lld ${DEBUG_PREFIX_MAP} -fdebug-prefix-map=${STAGING_KERNEL_DIR}=${KERNEL_SRC_PATH}"
 KERNEL_LD:toolchain-clang = "${CCACHE}ld.lld"
 KERNEL_AR:toolchain-clang = "${CCACHE}llvm-ar"
 
+# explicitly enable LLVM
+# https://docs.kernel.org/kbuild/llvm.html
+KERNEL_EXTRA_ARGS += "LLVM=1"
+
+# verbose build
+KERNEL_EXTRA_ARGS += "V=1"
+
 # FIXME: hacks
 do_kernel_configcheck[noexec] = "1"
-CFLAGS:append:toolchain-clang = " -Wno-error=address-of-packed-member"
+
+# error: taking address of packed member 'xxx' of class or structure 'yyy' may result in an unaligned pointer value [-Werror,-Waddress-of-packed-member]
+# kernel build use BUILD_CFLAGS instaed of CFLAGS
+#CFLAGS:append:toolchain-clang = " -Wno-address-of-packed-member"
+#BUILD_CFLAGS:append:toolchain-clang = " -Wno-address-of-packed-member"
+#BUILD_CXXFLAGS:append:toolchain-clang = " -Wno-address-of-packed-member"
+# none of the above works!
+# because kernel don't use CFLAGS we need to pass it over EXTRA_OEMAKE
+EXTRA_OEMAKE += 'CFLAGS="-Wno-address-of-packed-member"'
+
+# needed on kirkstone: don't fix the fail
+#EXTRA_OEMAKE += 'AR="${KERNEL_AR}"'