Re: [Xen-devel] [PATCH MM-PART2 RESEND v2 10/19] xen/arm32: head: Correctly report the HW CPU ID

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Tue, 14 May 2019, Julien Grall wrote:
> There are no reason to consider the HW CPU ID will be 0 when the
> processor is part of a uniprocessor system. At best, this will result to
> conflicting output as the rest of Xen use the value directly read from
> MPIDR.
> 
> So remove the zeroing and logic to check if the CPU is part of a
> uniprocessor system.
> 
> Signed-off-by: Julien Grall <julien.grall@xxxxxxx>
> Reviewed-by: Andrii Anisov <andrii_anisov@xxxxxxxx>

Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>


> ---
>     Changes in v2:
>         - Add Andrii's reviewed-by
> ---
>  xen/arch/arm/arm32/head.S | 8 --------
>  1 file changed, 8 deletions(-)
> 
> diff --git a/xen/arch/arm/arm32/head.S b/xen/arch/arm/arm32/head.S
> index 9f40face98..d42a13556c 100644
> --- a/xen/arch/arm/arm32/head.S
> +++ b/xen/arch/arm/arm32/head.S
> @@ -124,16 +124,8 @@ GLOBAL(init_secondary)
>          mov   r12, #1                /* r12 := is_secondary_cpu */
>  
>  common_start:
> -        mov   r7, #0                 /* r7 := CPU ID. Initialy zero until we
> -                                      * find that multiprocessor extensions 
> are
> -                                      * present and the system is SMP */
>          mrc   CP32(r1, MPIDR)
> -        tst   r1, #MPIDR_SMP         /* Multiprocessor extension supported? 
> */
> -        beq   1f
> -        tst   r1, #MPIDR_UP          /* Uniprocessor system? */
> -        bne   1f
>          bic   r7, r1, #(~MPIDR_HWID_MASK) /* Mask out flags to get CPU ID */
> -1:
>  
>          /* Non-boot CPUs wait here until __cpu_up is ready for them */
>          teq   r12, #0
> -- 
> 2.11.0
> 

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