Add '-undef' to DTS_CPPFLAGS to avoid unwanted expansion of dts content that matches system-specific or gcc-specific predefined macros.
Example: A number of PowerPC related *.dts files in the kernel define a property named 'linux,network-index' which (w/o '-undef') is expanded to '1,network-index' by the preprocessor because of '#define linux 1.'
With '-undef' in place only the standard predefined macros are visible:
$ gcc -dM -E -undef - </dev/null #define __STDC_HOSTED__ 1 #define __STDC__ 1
Signed-off-by: Horst Kronstorfer hkronsto@frequentis.com --- dts/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/dts/Makefile b/dts/Makefile index 402dfe1..3c6bc18 100644 --- a/dts/Makefile +++ b/dts/Makefile @@ -36,7 +36,7 @@ $(error Your architecture does not have device tree support enabled. \ Please define CONFIG_ARCH_DEVICE_TREE))
# We preprocess the device tree file provide a useful define -DTS_CPPFLAGS := -DARCH_CPU_DTS="$(SRCTREE)/arch/$(ARCH)/dts/$(CONFIG_ARCH_DEVICE_TREE).dtsi" +DTS_CPPFLAGS := -undef -DARCH_CPU_DTS="$(SRCTREE)/arch/$(ARCH)/dts/$(CONFIG_ARCH_DEVICE_TREE).dtsi"
all: $(obj).depend $(LIB)