(In reply to Shung-Hsi Yu from comment #5) > The compilation error is coming from Clang/LLVM, maybe @Aaron has some clues > regarding Clang's support of machine constrain targeting ppc64le? Ah then clearly Z<> should have been used: +#ifdef CONFIG_CC_IS_CLANG +#define DS_FORM_CONSTRAINT "Z<>" +#else +#define DS_FORM_CONSTRAINT "YZ<>" +#endif WIW it doesn't make sense (read as: is invalid/undefined) to build modules with a different compiler.