Re: [Xen-devel] [PATCH 4/4] xen/arm: arm64: Remove MPIDR multiprocessing extensions check

[Julien Grall <julien.grall@xxxxxxx>]

Hi Wei,

On 25/05/16 03:10, Wei Chen wrote:
> In ARM64, the MPIDR multiprocessing extensions bit is reserved to 1.
Well, technically the bit is unamed for ARM64. So I would make clear 
that the name is from AArch32. Something along:
"The bit 31 (former bit Multiprocessing extensions bit in AArch32) is 
always RES1 for AArch64."
> So, the value check for this bit is no longer necessary on ARM64.
>
> Signed-off-by: Wei Chen <Wei.Chen@xxxxxxxxxx>
> ---
>   xen/arch/arm/arm64/head.S | 1 -
>   1 file changed, 1 deletion(-)
>
> diff --git a/xen/arch/arm/arm64/head.S b/xen/arch/arm/arm64/head.S
> index 3090beb..91e2817 100644
> --- a/xen/arch/arm/arm64/head.S
> +++ b/xen/arch/arm/arm64/head.S
> @@ -267,7 +267,6 @@ common_start:
>                                         * find that multiprocessor extensions 
> are
>                                         * present and the system is SMP  */
>           mrs   x0, mpidr_el1
> -        tbz   x0, _MPIDR_SMP, 1f     /* Multiprocessor extension not 
> supported? */
>           tbnz  x0, _MPIDR_UP, 1f      /* Uniprocessor system? */
>
>           ldr   x13, =(~MPIDR_HWID_MASK)
Regards,

--
Julien Grall

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