Linux 6.8 Will Make It More Clear When x86 32-bit Support Is Disabled

With Linux 6.7 there's now support for enabling/disabling 32-bit program support at boot-time. The "ia32_emulation=" argument can be used for enabling/disabling 32-bit user-space program support and the ability to support 32-bit system calls. Right now when forcing off the x86 32-bit support it can be confusing if the user is unaware as no warning is currently provided, but that is about to change.

Queued into tip/tip.git's x86/misc branch ahead of the Linux 6.8 merge window is a patch to make it more clear when the x86 32-bit support is disabled.

Rather than only getting an "Exec format error" when trying to run a 32-bit binary on a Linux x86_64 system with the support disabled, a warning will be added to the kernel log. On the first try of running a 32-bit program with the support disabled, this message will be shown as a notice in the log:

32-bit emulation disabled. You can reenable with ia32_emulation=on

A small but useful addition as more Linux distribution vendors begin eyeing paths for disabling x86 32-bit support potentially by default in the not too distant future. But for those still wanting x86 32-bit user-space support, via "ia32_emulation=on" as a boot argument is enough to restore the support.