[PATCH] arm64: consistently log boot/secondary CPU IDs

[Will Deacon]

On Wed, Sep 27, 2017 at 02:50:38PM +0100, Mark Rutland wrote:
> Currently we inconsistently log identifying information for the boot CPU
> and secondary CPUs. For the boot CPU, we log the MIDR and MPIDR across
> separate messages, whereas for the secondary CPUs we only log the MIDR.
> 
> In some cases, it would be useful to know the MPIDR of secondary CPUs,
> and it would be nice for these messages to be consistent.
> 
> This patch ensures that in the primary and secondary boot paths, we log
> both the MPIDR and MIDR in a single message, with a consistent format.
> the MPIDR is consistently padded to 10 hex characters to cover Aff3 in
> bits 39:32, so that IDs can be compared easily.
> 
> The newly redundant message in setup_arch() is removed.
> 
> Signed-off-by: Mark Rutland <mark.rutland at arm.com>
> Cc: Al Stone <ahs3 at redhat.com>
> Cc: Catalin Marinas <catalin.marinas at arm.com>
> Cc: Will Deacon <will.deacon at arm.com>
> ---
>  arch/arm64/kernel/setup.c | 5 ++---
>  arch/arm64/kernel/smp.c   | 6 ++++--
>  2 files changed, 6 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
> index d4b7405..819c1d1 100644
> --- a/arch/arm64/kernel/setup.c
> +++ b/arch/arm64/kernel/setup.c
> @@ -103,7 +103,8 @@ void __init smp_setup_processor_id(void)
>  	 * access percpu variable inside lock_release
>  	 */
>  	set_my_cpu_offset(0);
> -	pr_info("Booting Linux on physical CPU 0x%lx\n", (unsigned long)mpidr);
> +	pr_info("Booting Linux on physical CPU 0x%010lx [%08x]\n",
> +		(unsigned long)mpidr, read_cpuid_id());

We should probably be consistent in whether or not we include the '0x'
prefix for these hex numbers, otherwise it could get confusing. I don't mind
which way we go.

Will