Re: [PATCH 2/2] arch: wire-up clone6() syscall on x86

[Christian Brauner]

On Mon, May 27, 2019 at 12:02:37PM +0200, Arnd Bergmann wrote:
> On Sun, May 26, 2019 at 12:27 PM Christian Brauner <christian@xxxxxxxxxx> wrote:
> >
> > Wire up the clone6() call on x86.
> >
> > This patch only wires up clone6() on x86. Some of the arches look like they
> > need special assembly massaging and it is probably smarter if the
> > appropriate arch maintainers would do the actual wiring.
> 
> Why do some architectures need special cases here? I'd prefer to have
> new system calls always get defined in a way that avoids this, and
> have a common entry point for everyone.
> 
> Looking at the m68k sys_clone comment in
> arch/m68k/kernel/process.c, it seems that this was done as an
> optimization to deal with an inferior ABI. Similar code is present
> in h8300, ia64, nios2, and sparc. If all of them just do this to
> shave off a few cycles from the system call entry, I really
> couldn't care less.

I'm happy to wire all arches up at the same time in the next revision. I
just wasn't sure why some of them were assemblying the living hell out
of clone; especially ia64. I really didn't want to bother touching all
of this just for an initial RFC.

Christian