Linux Considers Removing Old x32 ABI

Linux kernel developers are proposing the removal of the little-used x32 ABI to simplify the kernel and reduce its long-term maintenance burden.

A patch has been submitted to the Linux kernel mailing list proposing the retirement of the x32 ABI. This Application Binary Interface was designed for 64-bit (x86_64) processors, allowing programs to use the full 64-bit register set while using smaller 32-bit pointers for memory addresses. The primary goal was to reduce the memory footprint of applications that didn't require a large address space, offering a middle ground between traditional 32-bit and 64-bit systems. However, the feature was introduced relatively late in the 64-bit transition and never gained significant traction among developers or distributions. Its limited use has now prompted developers to question the value of its continued support.

The potential removal of the x32 ABI is significant as it signals a move towards simplifying the Linux kernel by removing niche features. This reduces the overall complexity and maintenance overhead for kernel developers, allowing them to focus on more widely used components. For security teams, removing unused code helps shrink the kernel's attack surface, potentially eliminating a source of future vulnerabilities. While the direct impact is limited to the small number of systems still using this specific ABI, the decision reflects a broader strategy of proactive maintenance and security hardening for the project.