Re: [RFC PATCH glibc 9/12] mach: Look for mach_i386.defs on x86_64 too

[Sergey Bugaev]

On Sun, Feb 12, 2023 at 6:46 PM Samuel Thibault <samuel.thibault@gnu.org> wrote:
>
> Sergey Bugaev, le dim. 12 févr. 2023 18:38:03 +0300, a ecrit:
> > Since mach/machine/syscall_sw.h is the i386 version on x86_64 (or --
> > is it not supposed to be?)
>
> Nobody yet decided that the system call interface would be the same on
> i386 and on x86_64 :)
>
> Most probably we'll need a different header, to put the trap number of
> rax instead of eax, notably. And the systemcall instruction will most
> probably not be an lcall.
>
> > the _MACH_I386_SYSCALL_SW_H_ guard is the one to fake, hence setting
> > mach-machine to i386.
>
> This can be already fixed by shipping a different file in mach, as we'll
> most probably want in the end anyway.

I've kind of assumed that the x86_64 Mach using / installing the i386
headers is intentional, and if some things (like the actual syscall
ABI) are to be different, they'd both be defined in the same file,
predicated on an ifdef. This is what XNU does for sure, see
osfmk/mach/i386/syscall_sw.h

Sergey