Re: [PATCH 3/8] s390/entry: shorten OUTSIDE macro

From: Heiko Carstens
Date: Thu May 12 2022 - 13:22:10 EST


On Wed, May 11, 2022 at 02:05:27PM +0200, Heiko Carstens wrote:
> Since the minimum architecture level has been raised to z10 a shorter
> instruction sequence can be used to implement the OUTSIDE macro. This
> also reduces the number of used registers within that macro to one.
>
> Signed-off-by: Heiko Carstens <hca@xxxxxxxxxxxxx>
> ---
> arch/s390/kernel/entry.S | 8 +++-----
> 1 file changed, 3 insertions(+), 5 deletions(-)
>
> diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S
> index a6b45eaa3450..e1664b45090f 100644
> --- a/arch/s390/kernel/entry.S
> +++ b/arch/s390/kernel/entry.S
> @@ -169,11 +169,9 @@ _LPP_OFFSET = __LC_LPP
> * @outside_label: jump here if @reg is outside of [@start..@end)
> */
> .macro OUTSIDE reg,start,end,outside_label
> - lgr %r14,\reg
> - larl %r13,\start
> - slgr %r14,%r13
> - lghi %r13,\end - \start
> - clgr %r14,%r13
> + larl %r14,\start
> + slgrk %r14,\reg,%r14
> + clgfi %r14,\end - \start

Clever me.. slgrk was added with z196, and not z10.
So dropping this patch.