Re: [PATCH] x86: Start removing X86_X32_ABI

[H. Peter Anvin]

On May 26, 2026 3:40:51 AM PDT, Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> wrote:
>On 2026-05-23 14:43:52 [-0700], H. Peter Anvin wrote:
>> However, we can not recycle the syscall numbers. The x32 flag in the
>> syscall number was advisory originally; it was introduced late in the
>> game to work around a design bug in the input subsystem (*).
>
>If x32 is removed/ not supported why can't the 32/64 bit ABI use syscall
>numbers 512+? It is an ELF32 with EM_X86_64 which should be rejected.
>Shouldn't this free the space because there are no users anymore?
>
>>    -hpa
>
>Sebastian

System call numbers or even mechanisms are in no wise tied to the ELF type. An x86-64 binary can issue x86-64, x32 or i386 system calls, even from 64-bit mode!