[PATCH] PCI: dwc: fix crash seen due to missing ops

[PATCH] PCI: dwc: fix crash seen due to missing ops

[Niklas Cassel]

From: Niklas Cassel <niklas.cassel@axis.com>

Fix the following crash, seen in dwc/pcie-artpec6.

  Unable to handle kernel NULL pointer dereference at virtual address 00000004
  pgd = c0204000
  [00000004] *pgd=00000000
  Internal error: Oops: 5 [#1] SMP ARM
  Modules linked in:
  CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.11.0-rc3-next-20170321 #1
  Hardware name: Axis ARTPEC-6 Platform
  task: db098000 task.stack: db096000
  PC is at dw_pcie_writel_dbi+0x2c/0xd0
  ...

While at it, fix the same problem for pcie-designware-plat.

Fixes: 442ec4c04d12 ("PCI: dwc: all: Split struct pcie_port into host-only and core structures")
Signed-off-by: Niklas Cassel <niklas.cassel@axis.com>
---
 drivers/pci/dwc/pcie-artpec6.c         | 4 ++++
 drivers/pci/dwc/pcie-designware-plat.c | 4 ++++
 2 files changed, 8 insertions(+)

diff --git a/drivers/pci/dwc/pcie-artpec6.c b/drivers/pci/dwc/pcie-artpec6.c
index fcd3ef845883..6d23683c0892 100644
--- a/drivers/pci/dwc/pcie-artpec6.c
+++ b/drivers/pci/dwc/pcie-artpec6.c
@@ -234,6 +234,9 @@ static int artpec6_add_pcie_port(struct artpec6_pcie *artpec6_pcie,
 	return 0;
 }
 
+static const struct dw_pcie_ops dw_pcie_ops = {
+};
+
 static int artpec6_pcie_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -252,6 +255,7 @@ static int artpec6_pcie_probe(struct platform_device *pdev)
 		return -ENOMEM;
 
 	pci->dev = dev;
+	pci->ops = &dw_pcie_ops;
 
 	artpec6_pcie->pci = pci;
 
diff --git a/drivers/pci/dwc/pcie-designware-plat.c b/drivers/pci/dwc/pcie-designware-plat.c
index b6c832ba39dd..f20d494922ab 100644
--- a/drivers/pci/dwc/pcie-designware-plat.c
+++ b/drivers/pci/dwc/pcie-designware-plat.c
@@ -86,6 +86,9 @@ static int dw_plat_add_pcie_port(struct pcie_port *pp,
 	return 0;
 }
 
+static const struct dw_pcie_ops dw_pcie_ops = {
+};
+
 static int dw_plat_pcie_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -103,6 +106,7 @@ static int dw_plat_pcie_probe(struct platform_device *pdev)
 		return -ENOMEM;
 
 	pci->dev = dev;
+	pci->ops = &dw_pcie_ops;
 
 	dw_plat_pcie->pci = pci;
 
-- 
2.11.0

Re: [PATCH] PCI: dwc: fix crash seen due to missing ops

[Joao Pinto]

Hi Niklas,

Às 2:43 PM de 3/21/2017, Niklas Cassel escreveu:
> From: Niklas Cassel <niklas.cassel@axis.com>
> 
> Fix the following crash, seen in dwc/pcie-artpec6.
> 
>   Unable to handle kernel NULL pointer dereference at virtual address 00000004
>   pgd = c0204000
>   [00000004] *pgd=00000000
>   Internal error: Oops: 5 [#1] SMP ARM
>   Modules linked in:
>   CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.11.0-rc3-next-20170321 #1
>   Hardware name: Axis ARTPEC-6 Platform
>   task: db098000 task.stack: db096000
>   PC is at dw_pcie_writel_dbi+0x2c/0xd0
>   ...
> 
> While at it, fix the same problem for pcie-designware-plat.
> 
> Fixes: 442ec4c04d12 ("PCI: dwc: all: Split struct pcie_port into host-only and core structures")
> Signed-off-by: Niklas Cassel <niklas.cassel@axis.com>
> ---
>  drivers/pci/dwc/pcie-artpec6.c         | 4 ++++
>  drivers/pci/dwc/pcie-designware-plat.c | 4 ++++
>  2 files changed, 8 insertions(+)
> 
> diff --git a/drivers/pci/dwc/pcie-artpec6.c b/drivers/pci/dwc/pcie-artpec6.c
> index fcd3ef845883..6d23683c0892 100644
> --- a/drivers/pci/dwc/pcie-artpec6.c
> +++ b/drivers/pci/dwc/pcie-artpec6.c
> @@ -234,6 +234,9 @@ static int artpec6_add_pcie_port(struct artpec6_pcie *artpec6_pcie,
>  	return 0;
>  }
>  
> +static const struct dw_pcie_ops dw_pcie_ops = {
> +};
> +
>  static int artpec6_pcie_probe(struct platform_device *pdev)
>  {
>  	struct device *dev = &pdev->dev;
> @@ -252,6 +255,7 @@ static int artpec6_pcie_probe(struct platform_device *pdev)
>  		return -ENOMEM;
>  
>  	pci->dev = dev;
> +	pci->ops = &dw_pcie_ops;
>  
>  	artpec6_pcie->pci = pci;
>  
> diff --git a/drivers/pci/dwc/pcie-designware-plat.c b/drivers/pci/dwc/pcie-designware-plat.c
> index b6c832ba39dd..f20d494922ab 100644
> --- a/drivers/pci/dwc/pcie-designware-plat.c
> +++ b/drivers/pci/dwc/pcie-designware-plat.c
> @@ -86,6 +86,9 @@ static int dw_plat_add_pcie_port(struct pcie_port *pp,
>  	return 0;
>  }
>  
> +static const struct dw_pcie_ops dw_pcie_ops = {
> +};
> +
>  static int dw_plat_pcie_probe(struct platform_device *pdev)
>  {
>  	struct device *dev = &pdev->dev;
> @@ -103,6 +106,7 @@ static int dw_plat_pcie_probe(struct platform_device *pdev)
>  		return -ENOMEM;
>  
>  	pci->dev = dev;
> +	pci->ops = &dw_pcie_ops;
>  
>  	dw_plat_pcie->pci = pci;
>  
> 

In the case of pcie-designware-plat you have the declaration of pci->ops:
https://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci.git/tree/drivers/pci/dwc/pcie-designware-plat.c#n78

and in artpec6 in here:
https://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci.git/tree/drivers/pci/dwc/pcie-artpec6.c#n226

Both declarations are made previously of calling dw_pcie_host_init(), so why do
you need this dummy ops in the probe function? I never had that necessity.

Thanks,
Joao

Thanks,

Re: [PATCH] PCI: dwc: fix crash seen due to missing ops

[Niklas Cassel]

On 03/22/2017 04:47 PM, Joao Pinto wrote:
> Hi Niklas,
>
> Às 2:43 PM de 3/21/2017, Niklas Cassel escreveu:
>> From: Niklas Cassel <niklas.cassel@axis.com>
>>
>> Fix the following crash, seen in dwc/pcie-artpec6.
>>
>>   Unable to handle kernel NULL pointer dereference at virtual address 00000004
>>   pgd = c0204000
>>   [00000004] *pgd=00000000
>>   Internal error: Oops: 5 [#1] SMP ARM
>>   Modules linked in:
>>   CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.11.0-rc3-next-20170321 #1
>>   Hardware name: Axis ARTPEC-6 Platform
>>   task: db098000 task.stack: db096000
>>   PC is at dw_pcie_writel_dbi+0x2c/0xd0
>>   ...
>>
>> While at it, fix the same problem for pcie-designware-plat.
>>
>> Fixes: 442ec4c04d12 ("PCI: dwc: all: Split struct pcie_port into host-only and core structures")
>> Signed-off-by: Niklas Cassel <niklas.cassel@axis.com>
>> ---
>>  drivers/pci/dwc/pcie-artpec6.c         | 4 ++++
>>  drivers/pci/dwc/pcie-designware-plat.c | 4 ++++
>>  2 files changed, 8 insertions(+)
>>
>> diff --git a/drivers/pci/dwc/pcie-artpec6.c b/drivers/pci/dwc/pcie-artpec6.c
>> index fcd3ef845883..6d23683c0892 100644
>> --- a/drivers/pci/dwc/pcie-artpec6.c
>> +++ b/drivers/pci/dwc/pcie-artpec6.c
>> @@ -234,6 +234,9 @@ static int artpec6_add_pcie_port(struct artpec6_pcie *artpec6_pcie,
>>  	return 0;
>>  }
>>  
>> +static const struct dw_pcie_ops dw_pcie_ops = {
>> +};
>> +
>>  static int artpec6_pcie_probe(struct platform_device *pdev)
>>  {
>>  	struct device *dev = &pdev->dev;
>> @@ -252,6 +255,7 @@ static int artpec6_pcie_probe(struct platform_device *pdev)
>>  		return -ENOMEM;
>>  
>>  	pci->dev = dev;
>> +	pci->ops = &dw_pcie_ops;
>>  
>>  	artpec6_pcie->pci = pci;
>>  
>> diff --git a/drivers/pci/dwc/pcie-designware-plat.c b/drivers/pci/dwc/pcie-designware-plat.c
>> index b6c832ba39dd..f20d494922ab 100644
>> --- a/drivers/pci/dwc/pcie-designware-plat.c
>> +++ b/drivers/pci/dwc/pcie-designware-plat.c
>> @@ -86,6 +86,9 @@ static int dw_plat_add_pcie_port(struct pcie_port *pp,
>>  	return 0;
>>  }
>>  
>> +static const struct dw_pcie_ops dw_pcie_ops = {
>> +};
>> +
>>  static int dw_plat_pcie_probe(struct platform_device *pdev)
>>  {
>>  	struct device *dev = &pdev->dev;
>> @@ -103,6 +106,7 @@ static int dw_plat_pcie_probe(struct platform_device *pdev)
>>  		return -ENOMEM;
>>  
>>  	pci->dev = dev;
>> +	pci->ops = &dw_pcie_ops;
>>  
>>  	dw_plat_pcie->pci = pci;
>>  
>>
> In the case of pcie-designware-plat you have the declaration of pci->ops:
> https://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci.git/tree/drivers/pci/dwc/pcie-designware-plat.c#n78
>
> and in artpec6 in here:
> https://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci.git/tree/drivers/pci/dwc/pcie-artpec6.c#n226
>
> Both declarations are made previously of calling dw_pcie_host_init(), so why do
> you need this dummy ops in the probe function? I never had that necessity.

Hello Joao

Since commit 442ec4c04d12, we now have two different ops,
dw_pcie_ops (ops for dw_pcie) and dw_pcie_host_ops (ops for a pcie_port),
note that they are different. The dw_pcie_ops is missing for pcie-artpec6
and pcie-designware-plat (since we are using the generic link-up function).

Before commit 442ec4c04d12, dw_pcie_writel_dbi had dw_pcie_host_ops as
parameter, after the commit it has dw_pcie_ops as parameter.
It should crash on pcie-designware-plat as well, since there are other
functions, like dw_pcie_link_up, that assumes that pci->ops != null.

Another alternative to adding the dummy ops would be to add null checks
for all uses off pci->ops in pcie-designware.c.
I don't like the idea to sprinkle null checks everywhere pci->ops is used.

One could add a null check in dw_pcie_host_init, but without a dummy ops
we would still fail this check, so our drivers would still be non-functional
in Linus's tree.

Re: [PATCH] PCI: dwc: fix crash seen due to missing ops

[Kishon Vijay Abraham I]

Hi,

On Thursday 23 March 2017 01:10 PM, Niklas Cassel wrote:
> On 03/22/2017 04:47 PM, Joao Pinto wrote:
>> Hi Niklas,
>>
>> Às 2:43 PM de 3/21/2017, Niklas Cassel escreveu:
>>> From: Niklas Cassel <niklas.cassel@axis.com>
>>>
>>> Fix the following crash, seen in dwc/pcie-artpec6.
>>>
>>>   Unable to handle kernel NULL pointer dereference at virtual address 00000004
>>>   pgd = c0204000
>>>   [00000004] *pgd=00000000
>>>   Internal error: Oops: 5 [#1] SMP ARM
>>>   Modules linked in:
>>>   CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.11.0-rc3-next-20170321 #1
>>>   Hardware name: Axis ARTPEC-6 Platform
>>>   task: db098000 task.stack: db096000
>>>   PC is at dw_pcie_writel_dbi+0x2c/0xd0
>>>   ...
>>>
>>> While at it, fix the same problem for pcie-designware-plat.
>>>
>>> Fixes: 442ec4c04d12 ("PCI: dwc: all: Split struct pcie_port into host-only and core structures")
>>> Signed-off-by: Niklas Cassel <niklas.cassel@axis.com>
>>> ---
>>>  drivers/pci/dwc/pcie-artpec6.c         | 4 ++++
>>>  drivers/pci/dwc/pcie-designware-plat.c | 4 ++++
>>>  2 files changed, 8 insertions(+)
>>>
>>> diff --git a/drivers/pci/dwc/pcie-artpec6.c b/drivers/pci/dwc/pcie-artpec6.c
>>> index fcd3ef845883..6d23683c0892 100644
>>> --- a/drivers/pci/dwc/pcie-artpec6.c
>>> +++ b/drivers/pci/dwc/pcie-artpec6.c
>>> @@ -234,6 +234,9 @@ static int artpec6_add_pcie_port(struct artpec6_pcie *artpec6_pcie,
>>>  	return 0;
>>>  }
>>>  
>>> +static const struct dw_pcie_ops dw_pcie_ops = {
>>> +};
>>> +
>>>  static int artpec6_pcie_probe(struct platform_device *pdev)
>>>  {
>>>  	struct device *dev = &pdev->dev;
>>> @@ -252,6 +255,7 @@ static int artpec6_pcie_probe(struct platform_device *pdev)
>>>  		return -ENOMEM;
>>>  
>>>  	pci->dev = dev;
>>> +	pci->ops = &dw_pcie_ops;
>>>  
>>>  	artpec6_pcie->pci = pci;
>>>  
>>> diff --git a/drivers/pci/dwc/pcie-designware-plat.c b/drivers/pci/dwc/pcie-designware-plat.c
>>> index b6c832ba39dd..f20d494922ab 100644
>>> --- a/drivers/pci/dwc/pcie-designware-plat.c
>>> +++ b/drivers/pci/dwc/pcie-designware-plat.c
>>> @@ -86,6 +86,9 @@ static int dw_plat_add_pcie_port(struct pcie_port *pp,
>>>  	return 0;
>>>  }
>>>  
>>> +static const struct dw_pcie_ops dw_pcie_ops = {
>>> +};
>>> +
>>>  static int dw_plat_pcie_probe(struct platform_device *pdev)
>>>  {
>>>  	struct device *dev = &pdev->dev;
>>> @@ -103,6 +106,7 @@ static int dw_plat_pcie_probe(struct platform_device *pdev)
>>>  		return -ENOMEM;
>>>  
>>>  	pci->dev = dev;
>>> +	pci->ops = &dw_pcie_ops;
>>>  
>>>  	dw_plat_pcie->pci = pci;
>>>  
>>>
>> In the case of pcie-designware-plat you have the declaration of pci->ops:
>> https://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci.git/tree/drivers/pci/dwc/pcie-designware-plat.c#n78
>>
>> and in artpec6 in here:
>> https://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci.git/tree/drivers/pci/dwc/pcie-artpec6.c#n226
>>
>> Both declarations are made previously of calling dw_pcie_host_init(), so why do
>> you need this dummy ops in the probe function? I never had that necessity.
> 
> Hello Joao
> 
> Since commit 442ec4c04d12, we now have two different ops,
> dw_pcie_ops (ops for dw_pcie) and dw_pcie_host_ops (ops for a pcie_port),
> note that they are different. The dw_pcie_ops is missing for pcie-artpec6
> and pcie-designware-plat (since we are using the generic link-up function).
> 
> Before commit 442ec4c04d12, dw_pcie_writel_dbi had dw_pcie_host_ops as
> parameter, after the commit it has dw_pcie_ops as parameter.
> It should crash on pcie-designware-plat as well, since there are other
> functions, like dw_pcie_link_up, that assumes that pci->ops != null.
> 
> Another alternative to adding the dummy ops would be to add null checks
> for all uses off pci->ops in pcie-designware.c.
> I don't like the idea to sprinkle null checks everywhere pci->ops is used.

I'm okay either ways.

Acked-by: Kishon Vijay Abraham I <kishon@ti.com>

> 
> One could add a null check in dw_pcie_host_init, but without a dummy ops
> we would still fail this check, so our drivers would still be non-functional
> in Linus's tree.
> 

Re: [PATCH] PCI: dwc: fix crash seen due to missing ops

[Niklas Cassel]

Hello Bjorn


I think that it might be a good idea to include this for v4.11.
PCIe for artpec-6 SoC works fine on v4.10, if we manage to
include this before v4.11 gets released, PCIe for artpec-6 SoC
will work fine on v4.11 too.


Regards,
Niklas

On 03/27/2017 07:43 AM, Kishon Vijay Abraham I wrote:
(snip)
>>
>> Hello Joao
>>
>> Since commit 442ec4c04d12, we now have two different ops,
>> dw_pcie_ops (ops for dw_pcie) and dw_pcie_host_ops (ops for a pcie_port),
>> note that they are different. The dw_pcie_ops is missing for pcie-artpec6
>> and pcie-designware-plat (since we are using the generic link-up function).
>>
>> Before commit 442ec4c04d12, dw_pcie_writel_dbi had dw_pcie_host_ops as
>> parameter, after the commit it has dw_pcie_ops as parameter.
>> It should crash on pcie-designware-plat as well, since there are other
>> functions, like dw_pcie_link_up, that assumes that pci->ops != null.
>>
>> Another alternative to adding the dummy ops would be to add null checks
>> for all uses off pci->ops in pcie-designware.c.
>> I don't like the idea to sprinkle null checks everywhere pci->ops is used.
> 
> I'm okay either ways.
> 
> Acked-by: Kishon Vijay Abraham I <kishon@ti.com>
> 
>>
>> One could add a null check in dw_pcie_host_init, but without a dummy ops
>> we would still fail this check, so our drivers would still be non-functional
>> in Linus's tree.
>>

Re: [PATCH] PCI: dwc: fix crash seen due to missing ops

[Joao Pinto]

Às 7:19 AM de 3/23/2017, Niklas Cassel escreveu:
> On 03/22/2017 04:47 PM, Joao Pinto wrote:
>> Hi Niklas,
>>
>> Às 2:43 PM de 3/21/2017, Niklas Cassel escreveu:
>>> From: Niklas Cassel <niklas.cassel@axis.com>
>>>
>>> Fix the following crash, seen in dwc/pcie-artpec6.
>>>
>>>   Unable to handle kernel NULL pointer dereference at virtual address 00000004
>>>   pgd = c0204000
>>>   [00000004] *pgd=00000000
>>>   Internal error: Oops: 5 [#1] SMP ARM
>>>   Modules linked in:
>>>   CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.11.0-rc3-next-20170321 #1
>>>   Hardware name: Axis ARTPEC-6 Platform
>>>   task: db098000 task.stack: db096000
>>>   PC is at dw_pcie_writel_dbi+0x2c/0xd0
>>>   ...
>>>
>>> While at it, fix the same problem for pcie-designware-plat.
>>>
>>> Fixes: 442ec4c04d12 ("PCI: dwc: all: Split struct pcie_port into host-only and core structures")
>>> Signed-off-by: Niklas Cassel <niklas.cassel@axis.com>
>>> ---
>>>  drivers/pci/dwc/pcie-artpec6.c         | 4 ++++
>>>  drivers/pci/dwc/pcie-designware-plat.c | 4 ++++
>>>  2 files changed, 8 insertions(+)
>>>
>>> diff --git a/drivers/pci/dwc/pcie-artpec6.c b/drivers/pci/dwc/pcie-artpec6.c
>>> index fcd3ef845883..6d23683c0892 100644
>>> --- a/drivers/pci/dwc/pcie-artpec6.c
>>> +++ b/drivers/pci/dwc/pcie-artpec6.c
>>> @@ -234,6 +234,9 @@ static int artpec6_add_pcie_port(struct artpec6_pcie *artpec6_pcie,
>>>  	return 0;
>>>  }
>>>  
>>> +static const struct dw_pcie_ops dw_pcie_ops = {
>>> +};
>>> +
>>>  static int artpec6_pcie_probe(struct platform_device *pdev)
>>>  {
>>>  	struct device *dev = &pdev->dev;
>>> @@ -252,6 +255,7 @@ static int artpec6_pcie_probe(struct platform_device *pdev)
>>>  		return -ENOMEM;
>>>  
>>>  	pci->dev = dev;
>>> +	pci->ops = &dw_pcie_ops;
>>>  
>>>  	artpec6_pcie->pci = pci;
>>>  
>>> diff --git a/drivers/pci/dwc/pcie-designware-plat.c b/drivers/pci/dwc/pcie-designware-plat.c
>>> index b6c832ba39dd..f20d494922ab 100644
>>> --- a/drivers/pci/dwc/pcie-designware-plat.c
>>> +++ b/drivers/pci/dwc/pcie-designware-plat.c
>>> @@ -86,6 +86,9 @@ static int dw_plat_add_pcie_port(struct pcie_port *pp,
>>>  	return 0;
>>>  }
>>>  
>>> +static const struct dw_pcie_ops dw_pcie_ops = {
>>> +};
>>> +
>>>  static int dw_plat_pcie_probe(struct platform_device *pdev)
>>>  {
>>>  	struct device *dev = &pdev->dev;
>>> @@ -103,6 +106,7 @@ static int dw_plat_pcie_probe(struct platform_device *pdev)
>>>  		return -ENOMEM;
>>>  
>>>  	pci->dev = dev;
>>> +	pci->ops = &dw_pcie_ops;
>>>  
>>>  	dw_plat_pcie->pci = pci;
>>>  
>>>
>> In the case of pcie-designware-plat you have the declaration of pci->ops:
>> https://urldefense.proofpoint.com/v2/url?u=https-3A__git.kernel.org_pub_scm_linux_kernel_git_helgaas_pci.git_tree_drivers_pci_dwc_pcie-2Ddesignware-2Dplat.c-23n78&d=DwID-g&c=DPL6_X_6JkXFx7AXWqB0tg&r=s2fO0hii0OGNOv9qQy_HRXy-xAJUD1NNoEcc3io_kx0&m=28B2KMSJPmdGukxJhVcT-K6O76mP27iVn-XTqDwJ4p0&s=glxSZ800DErbgYPvxr-U26UBSVliExhaYEW-MIYIs7U&e= 
>>
>> and in artpec6 in here:
>> https://urldefense.proofpoint.com/v2/url?u=https-3A__git.kernel.org_pub_scm_linux_kernel_git_helgaas_pci.git_tree_drivers_pci_dwc_pcie-2Dartpec6.c-23n226&d=DwID-g&c=DPL6_X_6JkXFx7AXWqB0tg&r=s2fO0hii0OGNOv9qQy_HRXy-xAJUD1NNoEcc3io_kx0&m=28B2KMSJPmdGukxJhVcT-K6O76mP27iVn-XTqDwJ4p0&s=_9PXmcF7fsBh4pqYI4lOl4kwCY48xSyUzg6VlCDIy9w&e= 
>>
>> Both declarations are made previously of calling dw_pcie_host_init(), so why do
>> you need this dummy ops in the probe function? I never had that necessity.
> 
> Hello Joao
> 
> Since commit 442ec4c04d12, we now have two different ops,
> dw_pcie_ops (ops for dw_pcie) and dw_pcie_host_ops (ops for a pcie_port),
> note that they are different. The dw_pcie_ops is missing for pcie-artpec6
> and pcie-designware-plat (since we are using the generic link-up function).
> 
> Before commit 442ec4c04d12, dw_pcie_writel_dbi had dw_pcie_host_ops as
> parameter, after the commit it has dw_pcie_ops as parameter.
> It should crash on pcie-designware-plat as well, since there are other
> functions, like dw_pcie_link_up, that assumes that pci->ops != null.
> 
> Another alternative to adding the dummy ops would be to add null checks
> for all uses off pci->ops in pcie-designware.c.
> I don't like the idea to sprinkle null checks everywhere pci->ops is used.
> 
> One could add a null check in dw_pcie_host_init, but without a dummy ops
> we would still fail this check, so our drivers would still be non-functional
> in Linus's tree.

Agree.
Acked-by: Joao Pinto <jpinto@synopsys.com>

Re: [PATCH] PCI: dwc: fix crash seen due to missing ops

[Bjorn Helgaas]

On Tue, Mar 21, 2017 at 03:43:54PM +0100, Niklas Cassel wrote:
> From: Niklas Cassel <niklas.cassel@axis.com>
> 
> Fix the following crash, seen in dwc/pcie-artpec6.
> 
>   Unable to handle kernel NULL pointer dereference at virtual address 00000004
>   pgd = c0204000
>   [00000004] *pgd=00000000
>   Internal error: Oops: 5 [#1] SMP ARM
>   Modules linked in:
>   CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.11.0-rc3-next-20170321 #1
>   Hardware name: Axis ARTPEC-6 Platform
>   task: db098000 task.stack: db096000
>   PC is at dw_pcie_writel_dbi+0x2c/0xd0
>   ...
> 
> While at it, fix the same problem for pcie-designware-plat.
> 
> Fixes: 442ec4c04d12 ("PCI: dwc: all: Split struct pcie_port into host-only and core structures")
> Signed-off-by: Niklas Cassel <niklas.cassel@axis.com>

For artpec6, I think this has already been fixed by Kishon's "PCI: dwc:
artpec6: Populate cpu_addr_fixup ops".

Since both the artpec6 and designware-plat issues were introduced by
442ec4c04d12, which we merged in the v4.11 merge window, I moved Kishon's
fix and the designware-plat part of this patch to for-linus for v4.11.

Please double-check my for-linus branch to make sure it has what we need.

> ---
>  drivers/pci/dwc/pcie-artpec6.c         | 4 ++++
>  drivers/pci/dwc/pcie-designware-plat.c | 4 ++++
>  2 files changed, 8 insertions(+)
> 
> diff --git a/drivers/pci/dwc/pcie-artpec6.c b/drivers/pci/dwc/pcie-artpec6.c
> index fcd3ef845883..6d23683c0892 100644
> --- a/drivers/pci/dwc/pcie-artpec6.c
> +++ b/drivers/pci/dwc/pcie-artpec6.c
> @@ -234,6 +234,9 @@ static int artpec6_add_pcie_port(struct artpec6_pcie *artpec6_pcie,
>  	return 0;
>  }
>  
> +static const struct dw_pcie_ops dw_pcie_ops = {
> +};
> +
>  static int artpec6_pcie_probe(struct platform_device *pdev)
>  {
>  	struct device *dev = &pdev->dev;
> @@ -252,6 +255,7 @@ static int artpec6_pcie_probe(struct platform_device *pdev)
>  		return -ENOMEM;
>  
>  	pci->dev = dev;
> +	pci->ops = &dw_pcie_ops;
>  
>  	artpec6_pcie->pci = pci;
>  
> diff --git a/drivers/pci/dwc/pcie-designware-plat.c b/drivers/pci/dwc/pcie-designware-plat.c
> index b6c832ba39dd..f20d494922ab 100644
> --- a/drivers/pci/dwc/pcie-designware-plat.c
> +++ b/drivers/pci/dwc/pcie-designware-plat.c
> @@ -86,6 +86,9 @@ static int dw_plat_add_pcie_port(struct pcie_port *pp,
>  	return 0;
>  }
>  
> +static const struct dw_pcie_ops dw_pcie_ops = {
> +};
> +
>  static int dw_plat_pcie_probe(struct platform_device *pdev)
>  {
>  	struct device *dev = &pdev->dev;
> @@ -103,6 +106,7 @@ static int dw_plat_pcie_probe(struct platform_device *pdev)
>  		return -ENOMEM;
>  
>  	pci->dev = dev;
> +	pci->ops = &dw_pcie_ops;
>  
>  	dw_plat_pcie->pci = pci;
>  
> -- 
> 2.11.0
> 

Re: [PATCH] PCI: dwc: fix crash seen due to missing ops

[Niklas Cassel]

On 04/04/2017 01:15 AM, Bjorn Helgaas wrote:
> On Tue, Mar 21, 2017 at 03:43:54PM +0100, Niklas Cassel wrote:
>> From: Niklas Cassel <niklas.cassel@axis.com>
>>
>> Fix the following crash, seen in dwc/pcie-artpec6.
>>
>>   Unable to handle kernel NULL pointer dereference at virtual address 00000004
>>   pgd = c0204000
>>   [00000004] *pgd=00000000
>>   Internal error: Oops: 5 [#1] SMP ARM
>>   Modules linked in:
>>   CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.11.0-rc3-next-20170321 #1
>>   Hardware name: Axis ARTPEC-6 Platform
>>   task: db098000 task.stack: db096000
>>   PC is at dw_pcie_writel_dbi+0x2c/0xd0
>>   ...
>>
>> While at it, fix the same problem for pcie-designware-plat.
>>
>> Fixes: 442ec4c04d12 ("PCI: dwc: all: Split struct pcie_port into host-only and core structures")
>> Signed-off-by: Niklas Cassel <niklas.cassel@axis.com>
> 
> For artpec6, I think this has already been fixed by Kishon's "PCI: dwc:
> artpec6: Populate cpu_addr_fixup ops".

Agreed.

> 
> Since both the artpec6 and designware-plat issues were introduced by
> 442ec4c04d12, which we merged in the v4.11 merge window, I moved Kishon's
> fix and the designware-plat part of this patch to for-linus for v4.11.

I didn't think that including "PCI: dwc: designware: Add new *ops* for
CPU addr fixup" was an option, but doing so is a cleaner solution imo.

> 
> Please double-check my for-linus branch to make sure it has what we need.

The branch looks good. I did test it, and it works marvelously.

> 
>> ---
>>  drivers/pci/dwc/pcie-artpec6.c         | 4 ++++
>>  drivers/pci/dwc/pcie-designware-plat.c | 4 ++++
>>  2 files changed, 8 insertions(+)
>>
>> diff --git a/drivers/pci/dwc/pcie-artpec6.c b/drivers/pci/dwc/pcie-artpec6.c
>> index fcd3ef845883..6d23683c0892 100644
>> --- a/drivers/pci/dwc/pcie-artpec6.c
>> +++ b/drivers/pci/dwc/pcie-artpec6.c
>> @@ -234,6 +234,9 @@ static int artpec6_add_pcie_port(struct artpec6_pcie *artpec6_pcie,
>>  	return 0;
>>  }
>>  
>> +static const struct dw_pcie_ops dw_pcie_ops = {
>> +};
>> +
>>  static int artpec6_pcie_probe(struct platform_device *pdev)
>>  {
>>  	struct device *dev = &pdev->dev;
>> @@ -252,6 +255,7 @@ static int artpec6_pcie_probe(struct platform_device *pdev)
>>  		return -ENOMEM;
>>  
>>  	pci->dev = dev;
>> +	pci->ops = &dw_pcie_ops;
>>  
>>  	artpec6_pcie->pci = pci;
>>  
>> diff --git a/drivers/pci/dwc/pcie-designware-plat.c b/drivers/pci/dwc/pcie-designware-plat.c
>> index b6c832ba39dd..f20d494922ab 100644
>> --- a/drivers/pci/dwc/pcie-designware-plat.c
>> +++ b/drivers/pci/dwc/pcie-designware-plat.c
>> @@ -86,6 +86,9 @@ static int dw_plat_add_pcie_port(struct pcie_port *pp,
>>  	return 0;
>>  }
>>  
>> +static const struct dw_pcie_ops dw_pcie_ops = {
>> +};
>> +
>>  static int dw_plat_pcie_probe(struct platform_device *pdev)
>>  {
>>  	struct device *dev = &pdev->dev;
>> @@ -103,6 +106,7 @@ static int dw_plat_pcie_probe(struct platform_device *pdev)
>>  		return -ENOMEM;
>>  
>>  	pci->dev = dev;
>> +	pci->ops = &dw_pcie_ops;
>>  
>>  	dw_plat_pcie->pci = pci;
>>  
>> -- 
>> 2.11.0
>>

Re: [PATCH] PCI: dwc: fix crash seen due to missing ops

[Bjorn Helgaas]

On Tue, Apr 04, 2017 at 09:54:25AM +0200, Niklas Cassel wrote:
> On 04/04/2017 01:15 AM, Bjorn Helgaas wrote:
> > On Tue, Mar 21, 2017 at 03:43:54PM +0100, Niklas Cassel wrote:
> >> From: Niklas Cassel <niklas.cassel@axis.com>
> >>
> >> Fix the following crash, seen in dwc/pcie-artpec6.
> >>
> >>   Unable to handle kernel NULL pointer dereference at virtual address 00000004
> >>   pgd = c0204000
> >>   [00000004] *pgd=00000000
> >>   Internal error: Oops: 5 [#1] SMP ARM
> >>   Modules linked in:
> >>   CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.11.0-rc3-next-20170321 #1
> >>   Hardware name: Axis ARTPEC-6 Platform
> >>   task: db098000 task.stack: db096000
> >>   PC is at dw_pcie_writel_dbi+0x2c/0xd0
> >>   ...
> >>
> >> While at it, fix the same problem for pcie-designware-plat.
> >>
> >> Fixes: 442ec4c04d12 ("PCI: dwc: all: Split struct pcie_port into host-only and core structures")
> >> Signed-off-by: Niklas Cassel <niklas.cassel@axis.com>
> > 
> > For artpec6, I think this has already been fixed by Kishon's "PCI: dwc:
> > artpec6: Populate cpu_addr_fixup ops".
> 
> Agreed.
> 
> > 
> > Since both the artpec6 and designware-plat issues were introduced by
> > 442ec4c04d12, which we merged in the v4.11 merge window, I moved Kishon's
> > fix and the designware-plat part of this patch to for-linus for v4.11.
> 
> I didn't think that including "PCI: dwc: designware: Add new *ops* for
> CPU addr fixup" was an option, but doing so is a cleaner solution imo.
> 
> > 
> > Please double-check my for-linus branch to make sure it has what we need.
> 
> The branch looks good. I did test it, and it works marvelously.

Thanks a lot for testing it.  I had already reconsidered this and
decided that I don't really like patches that do two things at once,
i.e., the "CPU addr fixup" patch both fixes the CPU addr thing and
fixes the NULL pointer dereference as an unintended side effect.

So I ended up putting your original patch on for-linus, then rebasing
pci/host-designware on top of for-linus.  That way we have your simple
patch for v4.11 that fixes the NULL pointer problems, and the CPU addr
fixups will go in v4.12 along with the rest of that series.  It's much
ado about nothing, really, and could go either way.

> >> ---
> >>  drivers/pci/dwc/pcie-artpec6.c         | 4 ++++
> >>  drivers/pci/dwc/pcie-designware-plat.c | 4 ++++
> >>  2 files changed, 8 insertions(+)
> >>
> >> diff --git a/drivers/pci/dwc/pcie-artpec6.c b/drivers/pci/dwc/pcie-artpec6.c
> >> index fcd3ef845883..6d23683c0892 100644
> >> --- a/drivers/pci/dwc/pcie-artpec6.c
> >> +++ b/drivers/pci/dwc/pcie-artpec6.c
> >> @@ -234,6 +234,9 @@ static int artpec6_add_pcie_port(struct artpec6_pcie *artpec6_pcie,
> >>  	return 0;
> >>  }
> >>  
> >> +static const struct dw_pcie_ops dw_pcie_ops = {
> >> +};
> >> +
> >>  static int artpec6_pcie_probe(struct platform_device *pdev)
> >>  {
> >>  	struct device *dev = &pdev->dev;
> >> @@ -252,6 +255,7 @@ static int artpec6_pcie_probe(struct platform_device *pdev)
> >>  		return -ENOMEM;
> >>  
> >>  	pci->dev = dev;
> >> +	pci->ops = &dw_pcie_ops;
> >>  
> >>  	artpec6_pcie->pci = pci;
> >>  
> >> diff --git a/drivers/pci/dwc/pcie-designware-plat.c b/drivers/pci/dwc/pcie-designware-plat.c
> >> index b6c832ba39dd..f20d494922ab 100644
> >> --- a/drivers/pci/dwc/pcie-designware-plat.c
> >> +++ b/drivers/pci/dwc/pcie-designware-plat.c
> >> @@ -86,6 +86,9 @@ static int dw_plat_add_pcie_port(struct pcie_port *pp,
> >>  	return 0;
> >>  }
> >>  
> >> +static const struct dw_pcie_ops dw_pcie_ops = {
> >> +};
> >> +
> >>  static int dw_plat_pcie_probe(struct platform_device *pdev)
> >>  {
> >>  	struct device *dev = &pdev->dev;
> >> @@ -103,6 +106,7 @@ static int dw_plat_pcie_probe(struct platform_device *pdev)
> >>  		return -ENOMEM;
> >>  
> >>  	pci->dev = dev;
> >> +	pci->ops = &dw_pcie_ops;
> >>  
> >>  	dw_plat_pcie->pci = pci;
> >>  
> >> -- 
> >> 2.11.0
> >>