Subject: [PATCHv2 02/12] arm64: smp_plat: add get_logical_index

From: [email-masked] (Hanjun Guo)
Date: Tue, 19 May 2015 11:47:18 +0800

On 2015?05?19? 01:55, Mark Rutland wrote:
> On Mon, May 18, 2015 at 06:09:13PM +0100, Catalin Marinas wrote:
>> On Mon, May 18, 2015 at 11:38:13AM +0100, Mark Rutland wrote:
>>> The PSCI MIGRATE_INFO_UP_CPU call returns a physical ID, which we will
>>> need to map back to a Linux logical ID.
>>>
>>> Implement a reusable get_logical_index to map from a physical ID to a
>>> logical ID.
>>>
>>> Signed-off-by: Mark Rutland <[email-masked]>
>>> Acked-by: Lorenzo Pieralisi <[email-masked]>
>>> Cc: Catalin Marinas <[email-masked]>
>>> Cc: Will Deacon <[email-masked]>
>>> ---
>>>   arch/arm64/include/asm/smp_plat.h | 16 ++++++++++++++++
>>>   1 file changed, 16 insertions(+)
>>>
>>> diff --git a/arch/arm64/include/asm/smp_plat.h b/arch/arm64/include/asm/smp_plat.h
>>> index 8dcd61e..7abf757 100644
>>> --- a/arch/arm64/include/asm/smp_plat.h
>>> +++ b/arch/arm64/include/asm/smp_plat.h
>>> @@ -19,6 +19,8 @@
>>>   #ifndef __ASM_SMP_PLAT_H
>>>   #define __ASM_SMP_PLAT_H
>>>
>>> +#include <linux/cpumask.h>
>>> +
>>>   #include <asm/types.h>
>>>
>>>   struct mpidr_hash {
>>> @@ -39,6 +41,20 @@ static inline u32 mpidr_hash_size(void)
>>>    */
>>>   extern u64 __cpu_logical_map[NR_CPUS];
>>>   #define cpu_logical_map(cpu)    __cpu_logical_map[cpu]
>>> +/*
>>> + * Retrieve logical cpu index corresponding to a given MPIDR.Aff*
>>> + *  - mpidr: MPIDR.Aff* bits to be used for the look-up
>>> + *
>>> + * Returns the cpu logical index or -EINVAL on look-up error
>>> + */
>>> +static inline int get_logical_index(u64 mpidr)
>>> +{
>>> +	int cpu;
>>> +	for (cpu = 0; cpu < nr_cpu_ids; cpu++)
>>> +		if (cpu_logical_map(cpu) == mpidr)
>>> +			return cpu;
>>> +	return -EINVAL;
>>> +}
>>
>> Do we guarantee that mpidr here only contains the affinity bits (i.e. no
>> masking)?
>
> In the DT and ACPI probe paths we reject IDs with bits other than the
> aff bits set.

In ACPI case, it's explicitly clarified in the ACPI spec that only
contains aff bits.

Reviewed-by: Hanjun Guo <[email-masked]>

Thanks
Hanjun