Re: [PATCH v2] x86: Start removing X86_X32_ABI

[H. Peter Anvin]

On July 8, 2026 1:26:28 PM PDT, David Laight <david.laight.linux@xxxxxxxxx> wrote:
>On Wed, 8 Jul 2026 17:27:46 +0100 (BST)
>"Maciej W. Rozycki" <macro@xxxxxxxxxxx> wrote:
>
>> On Wed, 8 Jul 2026, Arnd Bergmann wrote:
>> 
>> > As I understand, it's a policy in Debian for debian-installer and
>> > the kernel packages to only provide kernels for the native
>> > architecture, i.e. 64-bit x86 kernels are only packaged for
>> > amd64 and not x32 or i686, and 64-bit Arm kernels are only
>> > packaged for arm64 but not armhf or formerly armel.  
>> 
>>  Weird, x32 vs x64 for the Intel ISA or say n32 vs n64 for the MIPS ISA 
>> are psABI variants rather than architectures.  All are native, just using 
>> different register usage conventions.
>
>IIRC n32 just uses the 32bit system calls.
>x32 can't do that due to the differing alignment of u64.
>So the x86-64 kernel has to have three sets of system call wrappers (etc).
>
>	David
>
>> 
>>  And the kernel is a bare metal application, it has nothing to do with the 
>> userland as far as the user psABI is concerned.  It could use yet another 
>> psABI and I suspect this is the case at least for some of the Linux ports 
>> (`-mregparm=' GCC option comes immediately to mind).  Insisting that the 
>> same compilation options are used for the kernel as with all the userland 
>> packages in a distribution seems artificial and unreasonable to me.
>> 
>>  BTW, at least with n32 the MIPS architecture permits CPU implementations 
>> that only support that psABI and not n64.  Never implemented, I believe, 
>> but just proves its nativity.
>> 
>>  FWIW,
>> 
>>   Maciej
>> 
>

A very small number, though. The vast majority are the same as either x64 or i386.