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SubjectRe: [PATCH 3/6] alpha: Unify the not-implemented system call entry name
On Fri, Aug 10, 2018 at 07:31:55PM -0700, Richard Henderson wrote:

> > +++ b/arch/alpha/kernel/entry.S
> > @@ -473,7 +473,7 @@ entSys:
> > bne $3, strace
> > beq $4, 1f
> > ldq $27, 0($5)
> > -1: jsr $26, ($27), alpha_ni_syscall
> > +1: jsr $26, ($27), sys_ni_syscall
> > ldgp $gp, 0($26)
> > blt $0, $syscall_error /* the call failed */
> > stq $0, 0($sp)
>
> Once upon a time I had a patch to make the hint
> be sys_gettimeofday, as the most common syscall.
> Dunno what happened to that.

Might as well... ptraced case has it, non-ptraced doesn't.

BTW, seeing that it's your code - why was unop used in
alpha_ni_syscall? I don't remember the rules re pipeline
stalls; is it that some earlier variants prefer unop to
nop in such places? It's not that microoptimizing that
one makes any difference, but just out of curiosity -
would something like
lda $0, -ENOSYS
stq $sp, 0($sp) /* sp != 0 */
ret
do just as well there?

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