diff mbox series

of: Fix cpu node iterator to not ignore disabled cpu nodes

Message ID 20181031144226.26747-1-robh@kernel.org
State Accepted
Commit c961cb3be9064d1097ccc019390f8b5739daafc6
Headers show
Series of: Fix cpu node iterator to not ignore disabled cpu nodes | expand

Commit Message

Rob Herring Oct. 31, 2018, 2:42 p.m. UTC
In most cases, nodes with 'status = "disabled";' are treated as if the
node is not present though it is a common bug to forget to check that.
However, cpu nodes are different in that "disabled" simply means offline
and the OS can bring the CPU core online. Commit f1f207e43b8a ("of: Add
cpu node iterator for_each_of_cpu_node()") followed the common behavior
of ignoring disabled cpu nodes. This breaks some powerpc systems (at
least NXP P50XX/e5500). Fix this by dropping the status check.

Fixes: 651d44f9679c ("of: use for_each_of_cpu_node iterator")
Fixes: f1f207e43b8a ("of: Add cpu node iterator for_each_of_cpu_node()")
Reported-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: Christian Zigotzky <chzigotzky@xenosoft.de>
Cc: Frank Rowand <frowand.list@gmail.com>
Signed-off-by: Rob Herring <robh@kernel.org>

---
 drivers/of/base.c | 2 --
 1 file changed, 2 deletions(-)

-- 
2.19.1

Comments

Christian Zigotzky Oct. 31, 2018, 4:40 p.m. UTC | #1
Thank you. I will test this patch tomorrow.

— Christian

Sent from my iPhone

> On 31. Oct 2018, at 15:42, Rob Herring <robh@kernel.org> wrote:

> 

> In most cases, nodes with 'status = "disabled";' are treated as if the

> node is not present though it is a common bug to forget to check that.

> However, cpu nodes are different in that "disabled" simply means offline

> and the OS can bring the CPU core online. Commit f1f207e43b8a ("of: Add

> cpu node iterator for_each_of_cpu_node()") followed the common behavior

> of ignoring disabled cpu nodes. This breaks some powerpc systems (at

> least NXP P50XX/e5500). Fix this by dropping the status check.

> 

> Fixes: 651d44f9679c ("of: use for_each_of_cpu_node iterator")

> Fixes: f1f207e43b8a ("of: Add cpu node iterator for_each_of_cpu_node()")

> Reported-by: Michael Ellerman <mpe@ellerman.id.au>

> Cc: Christian Zigotzky <chzigotzky@xenosoft.de>

> Cc: Frank Rowand <frowand.list@gmail.com>

> Signed-off-by: Rob Herring <robh@kernel.org>

> ---

> drivers/of/base.c | 2 --

> 1 file changed, 2 deletions(-)

> 

> diff --git a/drivers/of/base.c b/drivers/of/base.c

> index cc62da278663..e47c5ce6cd58 100644

> --- a/drivers/of/base.c

> +++ b/drivers/of/base.c

> @@ -776,8 +776,6 @@ struct device_node *of_get_next_cpu_node(struct device_node *prev)

>        if (!(of_node_name_eq(next, "cpu") ||

>              (next->type && !of_node_cmp(next->type, "cpu"))))

>            continue;

> -        if (!__of_device_is_available(next))

> -            continue;

>        if (of_node_get(next))

>            break;

>    }

> -- 

> 2.19.1

>
Michael Ellerman Nov. 1, 2018, 11:08 a.m. UTC | #2
Rob Herring <robh@kernel.org> writes:

> In most cases, nodes with 'status = "disabled";' are treated as if the

> node is not present though it is a common bug to forget to check that.

> However, cpu nodes are different in that "disabled" simply means offline

> and the OS can bring the CPU core online. Commit f1f207e43b8a ("of: Add

> cpu node iterator for_each_of_cpu_node()") followed the common behavior

> of ignoring disabled cpu nodes. This breaks some powerpc systems (at

> least NXP P50XX/e5500). Fix this by dropping the status check.

>

> Fixes: 651d44f9679c ("of: use for_each_of_cpu_node iterator")

> Fixes: f1f207e43b8a ("of: Add cpu node iterator for_each_of_cpu_node()")

> Reported-by: Michael Ellerman <mpe@ellerman.id.au>

> Cc: Christian Zigotzky <chzigotzky@xenosoft.de>

> Cc: Frank Rowand <frowand.list@gmail.com>

> Signed-off-by: Rob Herring <robh@kernel.org>

> ---

>  drivers/of/base.c | 2 --

>  1 file changed, 2 deletions(-)


This fixes my machine, thanks.

Tested-by: Michael Ellerman <mpe@ellerman.id.au>


It was actually originally reported to me by Christian, so also:

Reported-by: Christian Zigotzky <chzigotzky@xenosoft.de>


cheers

> diff --git a/drivers/of/base.c b/drivers/of/base.c

> index cc62da278663..e47c5ce6cd58 100644

> --- a/drivers/of/base.c

> +++ b/drivers/of/base.c

> @@ -776,8 +776,6 @@ struct device_node *of_get_next_cpu_node(struct device_node *prev)

>  		if (!(of_node_name_eq(next, "cpu") ||

>  		      (next->type && !of_node_cmp(next->type, "cpu"))))

>  			continue;

> -		if (!__of_device_is_available(next))

> -			continue;

>  		if (of_node_get(next))

>  			break;

>  	}

> -- 

> 2.19.1
Christian Zigotzky Nov. 1, 2018, 12:45 p.m. UTC | #3
On 01 November 2018 at 12:08PM, Michael Ellerman wrote:
> Rob Herring <robh@kernel.org> writes:

>

>> In most cases, nodes with 'status = "disabled";' are treated as if the

>> node is not present though it is a common bug to forget to check that.

>> However, cpu nodes are different in that "disabled" simply means offline

>> and the OS can bring the CPU core online. Commit f1f207e43b8a ("of: Add

>> cpu node iterator for_each_of_cpu_node()") followed the common behavior

>> of ignoring disabled cpu nodes. This breaks some powerpc systems (at

>> least NXP P50XX/e5500). Fix this by dropping the status check.

>>

>> Fixes: 651d44f9679c ("of: use for_each_of_cpu_node iterator")

>> Fixes: f1f207e43b8a ("of: Add cpu node iterator for_each_of_cpu_node()")

>> Reported-by: Michael Ellerman <mpe@ellerman.id.au>

>> Cc: Christian Zigotzky <chzigotzky@xenosoft.de>

>> Cc: Frank Rowand <frowand.list@gmail.com>

>> Signed-off-by: Rob Herring <robh@kernel.org>

>> ---

>>   drivers/of/base.c | 2 --

>>   1 file changed, 2 deletions(-)

> This fixes my machine, thanks.

>

> Tested-by: Michael Ellerman <mpe@ellerman.id.au>

>

> It was actually originally reported to me by Christian, so also:

>

> Reported-by: Christian Zigotzky <chzigotzky@xenosoft.de>

>

>

> cheers

>

>> diff --git a/drivers/of/base.c b/drivers/of/base.c

>> index cc62da278663..e47c5ce6cd58 100644

>> --- a/drivers/of/base.c

>> +++ b/drivers/of/base.c

>> @@ -776,8 +776,6 @@ struct device_node *of_get_next_cpu_node(struct device_node *prev)

>>   		if (!(of_node_name_eq(next, "cpu") ||

>>   		      (next->type && !of_node_cmp(next->type, "cpu"))))

>>   			continue;

>> -		if (!__of_device_is_available(next))

>> -			continue;

>>   		if (of_node_get(next))

>>   			break;

>>   	}

>> -- 

>> 2.19.1


Hi All,

Many thanks for your help! This patch fixes my P5020 board (dual core) 
and my virtual QEMU ppce500 machine (quad core).

Have a nice day!

Cheers,
Christian
diff mbox series

Patch

diff --git a/drivers/of/base.c b/drivers/of/base.c
index cc62da278663..e47c5ce6cd58 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -776,8 +776,6 @@  struct device_node *of_get_next_cpu_node(struct device_node *prev)
 		if (!(of_node_name_eq(next, "cpu") ||
 		      (next->type && !of_node_cmp(next->type, "cpu"))))
 			continue;
-		if (!__of_device_is_available(next))
-			continue;
 		if (of_node_get(next))
 			break;
 	}