Re: [RFC v2 PATCH 7/7] x86/entry: use int for syscall number; handle all invalid syscall nrs

[H. Peter Anvin]

On 5/12/21 5:09 AM, Thomas Gleixner wrote:
> > index 1d9db15fdc69..85f04ea0e368 100644
> > --- a/arch/x86/entry/entry_64.S
> > +++ b/arch/x86/entry/entry_64.S
> > @@ -108,7 +108,7 @@ SYM_INNER_LABEL(entry_SYSCALL_64_after_hwframe, SYM_L_GLOBAL)
> >   
> >   	/* IRQs are off. */
> >   	movq	%rsp, %rdi
> > -	movq	%rax, %rsi
> > +	movslq	%eax, %rsi
>
> This is wrong.
>
>    syscall(long number,...);
>
> So the above turns syscall(UINT_MAX + N, ...) into syscall(N, ...).

That is intentional, as (again) system calls are int. As stated in my 
reply to Ingo, I'll clean the various descriptions and try to capture 
the discussion better.

	-hpa