Originally Posted by BenCollver

...the article doesn't actually say anything about "switchable x86-32 binary support".

Originally Posted by https://www.theregister.com/2023/10/30/linux_kernel_6_7_rundown/

We suspect that quite a few distros would like to drop support for 32-bit x86 binaries, but a lot of people still use them. Ubuntu tried in 2019 but an outcry forced it to backtrack, so it just dropped support for 32-bit hardware. Users of 64-bit Ubuntu can still run 32-bit binaries today, and some of us do. This isn't just for gamers; for instance, The Reg FOSS desk still has WordPerfect 8 for Linux installed – released for free long before 64-bit PCs were even a daydream – and occasionally even uses it.

Part of the problem is that right now, 32-bit x86 support on 64-bit Linux comes in two separate parts: a set of 32-bit libraries that you can easily install, and inside the kernel itself, the 32-bit interfaces that those libraries need. Currently, if the kernel is compiled with those turned off, x86-32 code can't be executed. To make 32-bit support optional would be tricky; for example, vendors would have to supply two sets of kernels, one with 32-bit support and another without. So almost everyone just leaves it on.

A new patch will turn this into an option that the user can choose at boot time. That means that vendors could ship their distros with it turned off, but if the user installs 32-bit libraries, 32-bit binary support can be enabled; all that will be needed afterward is a reboot to run code built for older 386, 486, or Pentium chips.