[PATCH] ARM: DT/kernel: fix arch_match_cpu_phys_id to avoid erroneous match

[PATCH] ARM: DT/kernel: fix arch_match_cpu_phys_id to avoid erroneous match

[Sudeep KarkadaNagesha]

From: Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>

The MPIDR contains specific bitfields(MPIDR.Aff{2..0}) which uniquely
identify a CPU, in addition to some non-identifying information and
reserved bits. The ARM cpu binding defines the 'reg' property to only
contain the affinity bits, and any cpu nodes with other bits set in
their 'reg' entry are skipped.

As such it is not necessary to mask the phys_id with MPIDR_HWID_BITMASK,
and doing so could lead to matching erroneous CPU nodes in the device
tree. This patch removes the masking of the physical identifier.

Signed-off-by: Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Cc: Russell King <linux@arm.linux.org.uk>
---
 arch/arm/kernel/devtree.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c
index f35906b..41960fb 100644
--- a/arch/arm/kernel/devtree.c
+++ b/arch/arm/kernel/devtree.c
@@ -171,7 +171,7 @@ void __init arm_dt_init_cpu_maps(void)
 
 bool arch_match_cpu_phys_id(int cpu, u64 phys_id)
 {
-	return (phys_id & MPIDR_HWID_BITMASK) == cpu_logical_map(cpu);
+	return phys_id == cpu_logical_map(cpu);
 }
 
 /**
-- 
1.8.1.2

[PATCH] ARM: DT/kernel: fix arch_match_cpu_phys_id to avoid erroneous match

[Mark Rutland]

Hi,

I was just looking in devtree.c and I noticed this seems to have fallen
by the wayside. Given that this fixes a possible bug and there have been
no negative comments, I think it's good for mainline.

Could you place this in the patch system, assuming Russell has no
comments?

Cheers,
Mark.

On Mon, Oct 21, 2013 at 01:30:32PM +0100, Sudeep KarkadaNagesha wrote:
> From: Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>
> 
> The MPIDR contains specific bitfields(MPIDR.Aff{2..0}) which uniquely
> identify a CPU, in addition to some non-identifying information and
> reserved bits. The ARM cpu binding defines the 'reg' property to only
> contain the affinity bits, and any cpu nodes with other bits set in
> their 'reg' entry are skipped.
> 
> As such it is not necessary to mask the phys_id with MPIDR_HWID_BITMASK,
> and doing so could lead to matching erroneous CPU nodes in the device
> tree. This patch removes the masking of the physical identifier.
> 
> Signed-off-by: Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>
> Acked-by: Mark Rutland <mark.rutland@arm.com>
> Cc: Russell King <linux@arm.linux.org.uk>
> ---
>  arch/arm/kernel/devtree.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c
> index f35906b..41960fb 100644
> --- a/arch/arm/kernel/devtree.c
> +++ b/arch/arm/kernel/devtree.c
> @@ -171,7 +171,7 @@ void __init arm_dt_init_cpu_maps(void)
>  
>  bool arch_match_cpu_phys_id(int cpu, u64 phys_id)
>  {
> -	return (phys_id & MPIDR_HWID_BITMASK) == cpu_logical_map(cpu);
> +	return phys_id == cpu_logical_map(cpu);
>  }
>  
>  /**
> -- 
> 1.8.1.2
> 

[PATCH] ARM: DT/kernel: fix arch_match_cpu_phys_id to avoid erroneous match

[Sudeep Holla]

Hi Russell,

On 07/01/14 16:58, Mark Rutland wrote:
> Hi,
> 
> I was just looking in devtree.c and I noticed this seems to have fallen
> by the wayside. Given that this fixes a possible bug and there have been
> no negative comments, I think it's good for mainline.
> 
> Could you place this in the patch system, assuming Russell has no
> comments?
> 

Can I put this in patch tracker if you have no objections ?

Regards,
Sudeep

> Cheers,
> Mark.
> 
> On Mon, Oct 21, 2013 at 01:30:32PM +0100, Sudeep KarkadaNagesha wrote:
>> From: Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>
>>
>> The MPIDR contains specific bitfields(MPIDR.Aff{2..0}) which uniquely
>> identify a CPU, in addition to some non-identifying information and
>> reserved bits. The ARM cpu binding defines the 'reg' property to only
>> contain the affinity bits, and any cpu nodes with other bits set in
>> their 'reg' entry are skipped.
>>
>> As such it is not necessary to mask the phys_id with MPIDR_HWID_BITMASK,
>> and doing so could lead to matching erroneous CPU nodes in the device
>> tree. This patch removes the masking of the physical identifier.
>>
>> Signed-off-by: Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>
>> Acked-by: Mark Rutland <mark.rutland@arm.com>
>> Cc: Russell King <linux@arm.linux.org.uk>
>> ---
>>  arch/arm/kernel/devtree.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c
>> index f35906b..41960fb 100644
>> --- a/arch/arm/kernel/devtree.c
>> +++ b/arch/arm/kernel/devtree.c
>> @@ -171,7 +171,7 @@ void __init arm_dt_init_cpu_maps(void)
>>  
>>  bool arch_match_cpu_phys_id(int cpu, u64 phys_id)
>>  {
>> -	return (phys_id & MPIDR_HWID_BITMASK) == cpu_logical_map(cpu);
>> +	return phys_id == cpu_logical_map(cpu);
>>  }
>>  
>>  /**
>> -- 
>> 1.8.1.2
>>

[PATCH] ARM: DT/kernel: fix arch_match_cpu_phys_id to avoid erroneous match

[Russell King - ARM Linux]

On Wed, Jan 08, 2014 at 10:58:34AM +0000, Sudeep Holla wrote:
> Hi Russell,
> 
> On 07/01/14 16:58, Mark Rutland wrote:
> > Hi,
> > 
> > I was just looking in devtree.c and I noticed this seems to have fallen
> > by the wayside. Given that this fixes a possible bug and there have been
> > no negative comments, I think it's good for mainline.
> > 
> > Could you place this in the patch system, assuming Russell has no
> > comments?
> > 
> 
> Can I put this in patch tracker if you have no objections ?

Yes please.

-- 
FTTC broadband for 0.8mile line: 5.8Mbps down 500kbps up.  Estimation
in database were 13.1 to 19Mbit for a good line, about 7.5+ for a bad.
Estimate before purchase was "up to 13.2Mbit".

[PATCH] ARM: DT/kernel: fix arch_match_cpu_phys_id to avoid erroneous match

[Sudeep Holla]

On 08/01/14 18:02, Russell King - ARM Linux wrote:
> On Wed, Jan 08, 2014 at 10:58:34AM +0000, Sudeep Holla wrote:
>> Hi Russell,
>>
>> On 07/01/14 16:58, Mark Rutland wrote:
>>> Hi,
>>>
>>> I was just looking in devtree.c and I noticed this seems to have fallen
>>> by the wayside. Given that this fixes a possible bug and there have been
>>> no negative comments, I think it's good for mainline.
>>>
>>> Could you place this in the patch system, assuming Russell has no
>>> comments?
>>>
>>
>> Can I put this in patch tracker if you have no objections ?
> 
> Yes please.
> 

Thanks and it's done(7934/1).

Regards,
Sudeep