[Skiboot] [PATCH] Set POWER9 RPR SPR

[Vaidyanathan Srinivasan]

* Michael Neuling <mikey at neuling.org> [2017-06-27 12:53:40]:

> Set POWER9 RPR SPR to 0x00000103070F1F3F.  Same value as P8.
> 
> Without this, thread priorities inside a core don't work.
> 
> Signed-off-by: Michael Neuling <mikey at neuling.org>
> ---
>  asm/head.S | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/asm/head.S b/asm/head.S
> index 01b726ad3a..badb567c09 100644
> --- a/asm/head.S
> +++ b/asm/head.S
> @@ -734,6 +734,9 @@ init_shared_sprs:
>  	sync
>  	mtspr	SPR_HMEER,%r3
>  	isync
> +
> +	LOAD_IMM64(%r3,0x00000103070F1F3F)
> +	mtspr	SPR_RPR,%r3
>  9:	blr

Hostboot should set this up for us before we get to skiboot:
https://github.com/open-power/hostboot/blob/master/src/kernel/cpumgr.C#L335

and the value they choose is:
WAKEUP_RPR_VALUE =    0x0001032021223F;

Are we working around a hostboot bug in skiboot layer?

--Vaidy