arm64: vdso32: Enable Clang Compilation

Enable Clang Compilation for the vdso32 library.

Signed-off-by: Vincenzo Frascino <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Tested-by: Nathan Chancellor <[email protected]> # build
Tested-by: Stephen Boyd <[email protected]>
Reviewed-by: Nathan Chancellor <[email protected]>
Acked-by: Catalin Marinas <[email protected]>
Cc: Will Deacon <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

Author: fvincenzo

arch/arm64/kernel/vdso32/Makefile

@@ -10,7 +10,18 @@ include $(srctree)/lib/vdso/Makefile
 
 # Same as cc-*option, but using CC_COMPAT instead of CC
 ifeq ($(CONFIG_CC_IS_CLANG), y)
+COMPAT_GCC_TOOLCHAIN_DIR := $(dir $(shell which $(CROSS_COMPILE_COMPAT)elfedit))
+COMPAT_GCC_TOOLCHAIN := $(realpath $(COMPAT_GCC_TOOLCHAIN_DIR)/..)
+
+CC_COMPAT_CLANG_FLAGS := --target=$(notdir $(CROSS_COMPILE_COMPAT:%-=%))
+CC_COMPAT_CLANG_FLAGS += --prefix=$(COMPAT_GCC_TOOLCHAIN_DIR)
+CC_COMPAT_CLANG_FLAGS += -no-integrated-as -Qunused-arguments
+ifneq ($(COMPAT_GCC_TOOLCHAIN),)
+CC_COMPAT_CLANG_FLAGS += --gcc-toolchain=$(COMPAT_GCC_TOOLCHAIN)
+endif
+
 CC_COMPAT ?= $(CC)
+CC_COMPAT += $(CC_COMPAT_CLANG_FLAGS)
 else
 CC_COMPAT ?= $(CROSS_COMPILE_COMPAT)gcc
 endif