ELF: what should be part of the userspace headers?

I'm currently a bit lost trying to understand what from the following headers is part of the kernel <-> userspace ABI: include/asm/elf.h include/linux/elfcore.h include/linux/elf-em.h include/linux/elf-fdpic.h include/linux/elf.h include/linux/elf-em.h is used by include/linux/audit.h, but this usage doesn't seem to be part of the kernel <-> userspace interface? And which part of the ELF headers is part of the kernel <-> userspace interface? TIA Adrian -- Gentoo kernels are 42 times more popular than SUSE kernels among KLive users (a service by SUSE contractor Andrea Arcangeli that gathers data about kernels from many users worldwide). There are three kinds of lies: Lies, Damn Lies, and Statistics. Benjamin Disraeli