IA32 Emulation

modulename: tls.ko

and/or

ia32entry.ko

and/or

nosyscall.ko

configname: CONFIG_IA32_EMULATION

Linux Kernel Configuration
└─>Executable file formats / Emulations
└─>IA32 Emulation
In linux kernel since version 2.6.12  
Include code to run legacy 32-bit programs under a
64-bit kernel. You should likely turn this on, unless you're
100% sure that you don't have any 32-bit programs left.

source code:
selects
CONFIG_BINFMT_ELF
CONFIG_COMPAT_BINFMT_ELF
CONFIG_HAVE_UID16

depends
CONFIG_X86_64

is selected by
CONFIG_COMPAT_32