diff mbox series

[3/3] remoteproc: pru: Fix and cleanup firmware interrupt mapping logic

Message ID 20210323223839.17464-4-s-anna@ti.com (mailing list archive)
State New
Headers show
Series PRU firmware event/interrupt mapping fixes | expand

Commit Message

Suman Anna March 23, 2021, 10:38 p.m. UTC
The PRU firmware interrupt mappings are configured and unconfigured in
.start() and .stop() callbacks respectively using the variables 'evt_count'
and a 'mapped_irq' pointer. These variables are modified only during these
callbacks but are not re-initialized/reset properly during unwind or
failure paths. These stale values caused a kernel crash while stopping a
PRU remoteproc running a different firmware with no events on a subsequent
run after a previous run that was running a firmware with events.

Fix this crash by ensuring that the evt_count is 0 and the mapped_irq
pointer is set to NULL in pru_dispose_irq_mapping(). Also, reset these
variables properly during any failures in the .start() callback. While
at this, the pru_dispose_irq_mapping() callsites are all made to look
the same, moving any conditional logic to inside the function.

Fixes: c75c9fdac66e ("remoteproc: pru: Add support for PRU specific interrupt configuration")
Reported-by: Vignesh Raghavendra <vigneshr@ti.com>
Signed-off-by: Suman Anna <s-anna@ti.com>
---
 drivers/remoteproc/pru_rproc.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

Comments

Mathieu Poirier April 6, 2021, 11:47 p.m. UTC | #1
On Tue, Mar 23, 2021 at 05:38:39PM -0500, Suman Anna wrote:
> The PRU firmware interrupt mappings are configured and unconfigured in
> .start() and .stop() callbacks respectively using the variables 'evt_count'
> and a 'mapped_irq' pointer. These variables are modified only during these
> callbacks but are not re-initialized/reset properly during unwind or
> failure paths. These stale values caused a kernel crash while stopping a
> PRU remoteproc running a different firmware with no events on a subsequent
> run after a previous run that was running a firmware with events.
> 
> Fix this crash by ensuring that the evt_count is 0 and the mapped_irq
> pointer is set to NULL in pru_dispose_irq_mapping(). Also, reset these
> variables properly during any failures in the .start() callback. While
> at this, the pru_dispose_irq_mapping() callsites are all made to look
> the same, moving any conditional logic to inside the function.
> 
> Fixes: c75c9fdac66e ("remoteproc: pru: Add support for PRU specific interrupt configuration")
> Reported-by: Vignesh Raghavendra <vigneshr@ti.com>
> Signed-off-by: Suman Anna <s-anna@ti.com>
> ---
>  drivers/remoteproc/pru_rproc.c | 12 +++++++++---
>  1 file changed, 9 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/remoteproc/pru_rproc.c b/drivers/remoteproc/pru_rproc.c
> index 87b43976c51b..5df19acb90ed 100644
> --- a/drivers/remoteproc/pru_rproc.c
> +++ b/drivers/remoteproc/pru_rproc.c
> @@ -266,12 +266,17 @@ static void pru_rproc_create_debug_entries(struct rproc *rproc)
>  
>  static void pru_dispose_irq_mapping(struct pru_rproc *pru)
>  {
> -	while (pru->evt_count--) {
> +	if (!pru->mapped_irq)
> +		return;
> +
> +	while (pru->evt_count) {
> +		pru->evt_count--;
>  		if (pru->mapped_irq[pru->evt_count] > 0)
>  			irq_dispose_mapping(pru->mapped_irq[pru->evt_count]);
>  	}
>  
>  	kfree(pru->mapped_irq);
> +	pru->mapped_irq = NULL;
>  }
>  
>  /*
> @@ -324,6 +329,8 @@ static int pru_handle_intrmap(struct rproc *rproc)
>  	of_node_put(parent);
>  	if (!irq_parent) {
>  		kfree(pru->mapped_irq);
> +		pru->mapped_irq = NULL;
> +		pru->evt_count = 0;

Patch 1/3 introduced a check on @parent that doesn't free pru->mapped_irq.  I
would also expect that error path to do the same has what is done here.  And
looking further up I see the error path for !pru->mapped_irq doesn't set
pru->evt_count to zero.

Thanks,
Mathieu

>  		return -ENODEV;
>  	}
>  
> @@ -398,8 +405,7 @@ static int pru_rproc_stop(struct rproc *rproc)
>  	pru_control_write_reg(pru, PRU_CTRL_CTRL, val);
>  
>  	/* dispose irq mapping - new firmware can provide new mapping */
> -	if (pru->mapped_irq)
> -		pru_dispose_irq_mapping(pru);
> +	pru_dispose_irq_mapping(pru);
>  
>  	return 0;
>  }
> -- 
> 2.30.1
>
Suman Anna April 7, 2021, 2:34 p.m. UTC | #2
Hi Mathieu,

On 4/6/21 6:47 PM, Mathieu Poirier wrote:
> On Tue, Mar 23, 2021 at 05:38:39PM -0500, Suman Anna wrote:
>> The PRU firmware interrupt mappings are configured and unconfigured in
>> .start() and .stop() callbacks respectively using the variables 'evt_count'
>> and a 'mapped_irq' pointer. These variables are modified only during these
>> callbacks but are not re-initialized/reset properly during unwind or
>> failure paths. These stale values caused a kernel crash while stopping a
>> PRU remoteproc running a different firmware with no events on a subsequent
>> run after a previous run that was running a firmware with events.
>>
>> Fix this crash by ensuring that the evt_count is 0 and the mapped_irq
>> pointer is set to NULL in pru_dispose_irq_mapping(). Also, reset these
>> variables properly during any failures in the .start() callback. While
>> at this, the pru_dispose_irq_mapping() callsites are all made to look
>> the same, moving any conditional logic to inside the function.
>>
>> Fixes: c75c9fdac66e ("remoteproc: pru: Add support for PRU specific interrupt configuration")
>> Reported-by: Vignesh Raghavendra <vigneshr@ti.com>
>> Signed-off-by: Suman Anna <s-anna@ti.com>
>> ---
>>  drivers/remoteproc/pru_rproc.c | 12 +++++++++---
>>  1 file changed, 9 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/remoteproc/pru_rproc.c b/drivers/remoteproc/pru_rproc.c
>> index 87b43976c51b..5df19acb90ed 100644
>> --- a/drivers/remoteproc/pru_rproc.c
>> +++ b/drivers/remoteproc/pru_rproc.c
>> @@ -266,12 +266,17 @@ static void pru_rproc_create_debug_entries(struct rproc *rproc)
>>  
>>  static void pru_dispose_irq_mapping(struct pru_rproc *pru)
>>  {
>> -	while (pru->evt_count--) {
>> +	if (!pru->mapped_irq)
>> +		return;
>> +
>> +	while (pru->evt_count) {
>> +		pru->evt_count--;
>>  		if (pru->mapped_irq[pru->evt_count] > 0)
>>  			irq_dispose_mapping(pru->mapped_irq[pru->evt_count]);
>>  	}
>>  
>>  	kfree(pru->mapped_irq);
>> +	pru->mapped_irq = NULL;
>>  }
>>  
>>  /*
>> @@ -324,6 +329,8 @@ static int pru_handle_intrmap(struct rproc *rproc)
>>  	of_node_put(parent);
>>  	if (!irq_parent) {
>>  		kfree(pru->mapped_irq);
>> +		pru->mapped_irq = NULL;
>> +		pru->evt_count = 0;
> 
> Patch 1/3 introduced a check on @parent that doesn't free pru->mapped_irq.  I
> would also expect that error path to do the same has what is done here.  And
> looking further up I see the error path for !pru->mapped_irq doesn't set
> pru->evt_count to zero.

Good catch, thank you. I will fix these up in v2.

regards
Suman

> 
> Thanks,
> Mathieu
> 
>>  		return -ENODEV;
>>  	}
>>  
>> @@ -398,8 +405,7 @@ static int pru_rproc_stop(struct rproc *rproc)
>>  	pru_control_write_reg(pru, PRU_CTRL_CTRL, val);
>>  
>>  	/* dispose irq mapping - new firmware can provide new mapping */
>> -	if (pru->mapped_irq)
>> -		pru_dispose_irq_mapping(pru);
>> +	pru_dispose_irq_mapping(pru);
>>  
>>  	return 0;
>>  }
>> -- 
>> 2.30.1
>>
diff mbox series

Patch

diff --git a/drivers/remoteproc/pru_rproc.c b/drivers/remoteproc/pru_rproc.c
index 87b43976c51b..5df19acb90ed 100644
--- a/drivers/remoteproc/pru_rproc.c
+++ b/drivers/remoteproc/pru_rproc.c
@@ -266,12 +266,17 @@  static void pru_rproc_create_debug_entries(struct rproc *rproc)
 
 static void pru_dispose_irq_mapping(struct pru_rproc *pru)
 {
-	while (pru->evt_count--) {
+	if (!pru->mapped_irq)
+		return;
+
+	while (pru->evt_count) {
+		pru->evt_count--;
 		if (pru->mapped_irq[pru->evt_count] > 0)
 			irq_dispose_mapping(pru->mapped_irq[pru->evt_count]);
 	}
 
 	kfree(pru->mapped_irq);
+	pru->mapped_irq = NULL;
 }
 
 /*
@@ -324,6 +329,8 @@  static int pru_handle_intrmap(struct rproc *rproc)
 	of_node_put(parent);
 	if (!irq_parent) {
 		kfree(pru->mapped_irq);
+		pru->mapped_irq = NULL;
+		pru->evt_count = 0;
 		return -ENODEV;
 	}
 
@@ -398,8 +405,7 @@  static int pru_rproc_stop(struct rproc *rproc)
 	pru_control_write_reg(pru, PRU_CTRL_CTRL, val);
 
 	/* dispose irq mapping - new firmware can provide new mapping */
-	if (pru->mapped_irq)
-		pru_dispose_irq_mapping(pru);
+	pru_dispose_irq_mapping(pru);
 
 	return 0;
 }