Linux kernel patches propose disabling x32 ABI after 14 years of limited use

Linux kernel developers are taking concrete steps to retire the x32 ABI, a niche ILP32 compatibility layer introduced in 2012 that runs x86_64 code with 32-bit pointers. A new patch series from Linutronix developer Sebastian Andrzej Siewior would make the feature unselectable through normal kernel configuration by adding a BROKEN dependency, giving remaining users and distribution maintainers advance notice before eventual code removal. The x32 ABI never achieved mainstream adoption despite its theoretical memory-efficiency benefits for pointer-heavy workloads.

How the staged removal would work

• The patch targets CONFIG_X86_X32_ABI, the kernel symbol controlling x32 application execution support
• The proposed change adds depends on BROKEN, making the option invisible to normal configuration tools like menuconfig
• This is a staged approach: disabling selection first, deleting implementation code later
• x32 uses ILP32 data model: 32-bit int, long, and pointers, but runs in 64-bit CPU execution mode with full x86_64 register file
• The ABI was introduced in Linux 3.4 (2012) and requires special handling in system calls, data structures, and compatibility paths throughout the kernel

Why it matters

Few distributions still ship x32 packages, so most users will be unaffected. For the kernel maintainership, removing the ABI would eliminate a persistent maintenance burden across system-call compatibility, security review, and testing matrices.