diff mbox

irqchip: gicv3-its: fix ITS CPU init

Message ID 1420818645-2349-1-git-send-email-vladimir.murzin@arm.com
State New, archived
Headers show

Commit Message

Vladimir Murzin Jan. 9, 2015, 3:50 p.m. UTC
We skip initialisation of ITS in case the device-tree has no
corresponding description, but we are still accessing to ITS bits while
setting CPU interface what leads to the kernel panic:

ITS: No ITS available, not enabling LPIs
CPU0: found redistributor 0 region 0:0x000000002f100000
Unable to handle kernel NULL pointer dereference at virtual address 00000000
pgd = ffffffc0007fb000
[00000000] *pgd=00000000fc407003, *pud=00000000fc407003, *pmd=00000000fc408003, *pte=006000002f000707
Internal error: Oops: 96000005 [#1] PREEMPT SMP
Modules linked in:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.19.0-rc2+ #318
Hardware name: FVP Base (DT)
task: ffffffc00077edb0 ti: ffffffc00076c000 task.ti: ffffffc00076c000
PC is at its_cpu_init+0x2c/0x320
LR is at gic_cpu_init+0x168/0x1bc

It happens in gic_rdists_supports_plpis() because gic_rdists is NULL.
The gic_rdists is set to non-NULL only when ITS node is presented in
the device-tree.

Fix this by moving the call to gic_rdists_supports_plpis() inside the
!list_empty(&its_nodes) block, because it is that list that guards the
validity of the rest of the information in this driver.

Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
---
 drivers/irqchip/irq-gic-v3-its.c |    9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

Comments

Marc Zyngier Jan. 9, 2015, 4:10 p.m. UTC | #1
Hi Vladimir,

On 09/01/15 15:50, Vladimir Murzin wrote:
> We skip initialisation of ITS in case the device-tree has no
> corresponding description, but we are still accessing to ITS bits while
> setting CPU interface what leads to the kernel panic:
> 
> ITS: No ITS available, not enabling LPIs
> CPU0: found redistributor 0 region 0:0x000000002f100000
> Unable to handle kernel NULL pointer dereference at virtual address 00000000
> pgd = ffffffc0007fb000
> [00000000] *pgd=00000000fc407003, *pud=00000000fc407003, *pmd=00000000fc408003, *pte=006000002f000707
> Internal error: Oops: 96000005 [#1] PREEMPT SMP
> Modules linked in:
> CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.19.0-rc2+ #318
> Hardware name: FVP Base (DT)
> task: ffffffc00077edb0 ti: ffffffc00076c000 task.ti: ffffffc00076c000
> PC is at its_cpu_init+0x2c/0x320
> LR is at gic_cpu_init+0x168/0x1bc
> 
> It happens in gic_rdists_supports_plpis() because gic_rdists is NULL.
> The gic_rdists is set to non-NULL only when ITS node is presented in
> the device-tree.
> 
> Fix this by moving the call to gic_rdists_supports_plpis() inside the
> !list_empty(&its_nodes) block, because it is that list that guards the
> validity of the rest of the information in this driver.
> 
> Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>

Looks good to me.

Acked-by: Marc Zyngier <marc.zyngier@arm.com>

	M.

> ---
>  drivers/irqchip/irq-gic-v3-its.c |    9 ++++-----
>  1 file changed, 4 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
> index 86e4684..128a12b 100644
> --- a/drivers/irqchip/irq-gic-v3-its.c
> +++ b/drivers/irqchip/irq-gic-v3-its.c
> @@ -1382,12 +1382,11 @@ static bool gic_rdists_supports_plpis(void)
>  
>  int its_cpu_init(void)
>  {
> -	if (!gic_rdists_supports_plpis()) {
> -		pr_info("CPU%d: LPIs not supported\n", smp_processor_id());
> -		return -ENXIO;
> -	}
> -
>  	if (!list_empty(&its_nodes)) {
> +		if (!gic_rdists_supports_plpis()) {
> +			pr_info("CPU%d: LPIs not supported\n", smp_processor_id());
> +			return -ENXIO;
> +		}
>  		its_cpu_init_lpis();
>  		its_cpu_init_collection();
>  	}
>
Vladimir Murzin Jan. 23, 2015, 10:03 a.m. UTC | #2
On 09/01/15 16:10, Marc Zyngier wrote:
> Hi Vladimir,
> 
> On 09/01/15 15:50, Vladimir Murzin wrote:
>> We skip initialisation of ITS in case the device-tree has no
>> corresponding description, but we are still accessing to ITS bits while
>> setting CPU interface what leads to the kernel panic:
>>
>> ITS: No ITS available, not enabling LPIs
>> CPU0: found redistributor 0 region 0:0x000000002f100000
>> Unable to handle kernel NULL pointer dereference at virtual address 00000000
>> pgd = ffffffc0007fb000
>> [00000000] *pgd=00000000fc407003, *pud=00000000fc407003, *pmd=00000000fc408003, *pte=006000002f000707
>> Internal error: Oops: 96000005 [#1] PREEMPT SMP
>> Modules linked in:
>> CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.19.0-rc2+ #318
>> Hardware name: FVP Base (DT)
>> task: ffffffc00077edb0 ti: ffffffc00076c000 task.ti: ffffffc00076c000
>> PC is at its_cpu_init+0x2c/0x320
>> LR is at gic_cpu_init+0x168/0x1bc
>>
>> It happens in gic_rdists_supports_plpis() because gic_rdists is NULL.
>> The gic_rdists is set to non-NULL only when ITS node is presented in
>> the device-tree.
>>
>> Fix this by moving the call to gic_rdists_supports_plpis() inside the
>> !list_empty(&its_nodes) block, because it is that list that guards the
>> validity of the rest of the information in this driver.
>>
>> Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
> 
> Looks good to me.
> 
> Acked-by: Marc Zyngier <marc.zyngier@arm.com>
> 
> 	M.
> 

Thomas, Jason, are you OK with this patch?

Vladimir

>> ---
>>  drivers/irqchip/irq-gic-v3-its.c |    9 ++++-----
>>  1 file changed, 4 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
>> index 86e4684..128a12b 100644
>> --- a/drivers/irqchip/irq-gic-v3-its.c
>> +++ b/drivers/irqchip/irq-gic-v3-its.c
>> @@ -1382,12 +1382,11 @@ static bool gic_rdists_supports_plpis(void)
>>  
>>  int its_cpu_init(void)
>>  {
>> -	if (!gic_rdists_supports_plpis()) {
>> -		pr_info("CPU%d: LPIs not supported\n", smp_processor_id());
>> -		return -ENXIO;
>> -	}
>> -
>>  	if (!list_empty(&its_nodes)) {
>> +		if (!gic_rdists_supports_plpis()) {
>> +			pr_info("CPU%d: LPIs not supported\n", smp_processor_id());
>> +			return -ENXIO;
>> +		}
>>  		its_cpu_init_lpis();
>>  		its_cpu_init_collection();
>>  	}
>>
> 
>
diff mbox

Patch

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 86e4684..128a12b 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -1382,12 +1382,11 @@  static bool gic_rdists_supports_plpis(void)
 
 int its_cpu_init(void)
 {
-	if (!gic_rdists_supports_plpis()) {
-		pr_info("CPU%d: LPIs not supported\n", smp_processor_id());
-		return -ENXIO;
-	}
-
 	if (!list_empty(&its_nodes)) {
+		if (!gic_rdists_supports_plpis()) {
+			pr_info("CPU%d: LPIs not supported\n", smp_processor_id());
+			return -ENXIO;
+		}
 		its_cpu_init_lpis();
 		its_cpu_init_collection();
 	}