Re: [PATCH v3 1/5] ARM: kernel: smp_setup_processor_id() updates

[Will Deacon <will.deacon@arm.com>]

On Thu, Nov 15, 2012 at 12:46:50PM +0000, Lorenzo Pieralisi wrote:
> This patch applies some basic changes to the smp_setup_processor_id()
> ARM implementation to make the code that builds cpu_logical_map more
> uniform across the kernel.
> 
> The function now prints the full extent of the boot CPU MPIDR[23:0] and
> initializes the cpu_logical_map for CPUs up to nr_cpu_ids.
> 
> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> ---
>  arch/arm/kernel/setup.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
> index da1d1aa..d0df6c8 100644
> --- a/arch/arm/kernel/setup.c
> +++ b/arch/arm/kernel/setup.c
> @@ -426,13 +426,14 @@ int __cpu_logical_map[NR_CPUS];
>  void __init smp_setup_processor_id(void)
>  {
>  	int i;
> -	u32 cpu = is_smp() ? read_cpuid_mpidr() & 0xff : 0;
> +	u32 mpidr = is_smp() ? read_cpuid_mpidr() & 0xffffff : 0;
> +	u32 cpu = mpidr & 0xff;

Can we move the #defines out of topology.c and use those instead of magic
masks please? You could use MPIDR_HWID_BITMASK, although the LEVEL mask
definitions over there don't look right to me (MPIDR_LEVEL0_MASK is 0x3?)

Will