diff mbox series

[1/2] coresight: trbe: Fix TRBE potential sleep in atomic context

Message ID 20230814093813.19152-2-hejunhao3@huawei.com
State New
Headers
Series Fix some issues with TRBE building as a module |

Commit Message

hejunhao Aug. 14, 2023, 9:38 a.m. UTC 
  smp_call_function_single() will allocate an IPI interrupt vector to
the target processor and send a function call request to the interrupt
vector. After the target processor receives the IPI interrupt, it will
execute arm_trbe_remove_coresight_cpu() call request in the interrupt
handler.

According to the device_unregister() stack information, if other process
is useing the device, the down_write() may sleep, and trigger deadlocks
or unexpected errors.

  arm_trbe_remove_coresight_cpu
    coresight_unregister
      device_unregister
        device_del
          kobject_del
            __kobject_del
              sysfs_remove_dir
                kernfs_remove
                  down_write ---------> it may sleep

Add a helper arm_trbe_disable_cpu() to disable TRBE precpu irq and reset
per TRBE.
Simply call arm_trbe_remove_coresight_cpu() directly without useing the
smp_call_function_single(), which is the same as registering the TRBE
coresight device.

Fixes: 3fbf7f011f24 ("coresight: sink: Add TRBE driver")
Signed-off-by: Junhao He <hejunhao3@huawei.com>
---
 drivers/hwtracing/coresight/coresight-trbe.c | 35 +++++++++++---------
 1 file changed, 20 insertions(+), 15 deletions(-)

Comments

Suzuki K Poulose Aug. 14, 2023, 10:34 a.m. UTC | #1 
Hi Junhao

On 14/08/2023 10:38, Junhao He wrote:
> smp_call_function_single() will allocate an IPI interrupt vector to
> the target processor and send a function call request to the interrupt
> vector. After the target processor receives the IPI interrupt, it will
> execute arm_trbe_remove_coresight_cpu() call request in the interrupt
> handler.
> 
> According to the device_unregister() stack information, if other process
> is useing the device, the down_write() may sleep, and trigger deadlocks
> or unexpected errors.
> 
>    arm_trbe_remove_coresight_cpu
>      coresight_unregister
>        device_unregister
>          device_del
>            kobject_del
>              __kobject_del
>                sysfs_remove_dir
>                  kernfs_remove
>                    down_write ---------> it may sleep
> 
> Add a helper arm_trbe_disable_cpu() to disable TRBE precpu irq and reset
> per TRBE.
> Simply call arm_trbe_remove_coresight_cpu() directly without useing the
> smp_call_function_single(), which is the same as registering the TRBE
> coresight device.
> 
> Fixes: 3fbf7f011f24 ("coresight: sink: Add TRBE driver")
> Signed-off-by: Junhao He <hejunhao3@huawei.com>
> ---
>   drivers/hwtracing/coresight/coresight-trbe.c | 35 +++++++++++---------
>   1 file changed, 20 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c
> index 7720619909d6..ce1e6f537b8d 100644
> --- a/drivers/hwtracing/coresight/coresight-trbe.c
> +++ b/drivers/hwtracing/coresight/coresight-trbe.c
> @@ -1225,6 +1225,17 @@ static void arm_trbe_enable_cpu(void *info)
>   	enable_percpu_irq(drvdata->irq, IRQ_TYPE_NONE);
>   }
>   
> +static void arm_trbe_disable_cpu(void *info)
> +{
> +	struct trbe_drvdata *drvdata = info;
> +	struct trbe_cpudata *cpudata = this_cpu_ptr(drvdata->cpudata);
> +
> +	disable_percpu_irq(drvdata->irq);
> +	trbe_reset_local(cpudata);
> +	cpudata->drvdata = NULL;
> +}
> +
> +
>   static void arm_trbe_register_coresight_cpu(struct trbe_drvdata *drvdata, int cpu)
>   {
>   	struct trbe_cpudata *cpudata = per_cpu_ptr(drvdata->cpudata, cpu);
> @@ -1326,18 +1337,12 @@ static void arm_trbe_probe_cpu(void *info)
>   	cpumask_clear_cpu(cpu, &drvdata->supported_cpus);
>   }
>   
> -static void arm_trbe_remove_coresight_cpu(void *info)
> +static void arm_trbe_remove_coresight_cpu(struct trbe_drvdata *drvdata, int cpu)
>   {
> -	int cpu = smp_processor_id();
> -	struct trbe_drvdata *drvdata = info;
> -	struct trbe_cpudata *cpudata = per_cpu_ptr(drvdata->cpudata, cpu);
>   	struct coresight_device *trbe_csdev = coresight_get_percpu_sink(cpu);
>   
> -	disable_percpu_irq(drvdata->irq);
> -	trbe_reset_local(cpudata);
>   	if (trbe_csdev) {
>   		coresight_unregister(trbe_csdev);
> -		cpudata->drvdata = NULL;
>   		coresight_set_percpu_sink(cpu, NULL);

I am a bit concerned about "resetting" the sink from a different CPU.
Could we instead, schedule a delayed work to unregister the trbe_csdev?


Suzuki


>   	}
>   }
> @@ -1366,8 +1371,12 @@ static int arm_trbe_remove_coresight(struct trbe_drvdata *drvdata)
>   {
>   	int cpu;
>   
> -	for_each_cpu(cpu, &drvdata->supported_cpus)
> -		smp_call_function_single(cpu, arm_trbe_remove_coresight_cpu, drvdata, 1);
> +	for_each_cpu(cpu, &drvdata->supported_cpus) {
> +		if (cpumask_test_cpu(cpu, &drvdata->supported_cpus))
> +			smp_call_function_single(cpu, arm_trbe_disable_cpu, drvdata, 1);
> +		if (cpumask_test_cpu(cpu, &drvdata->supported_cpus))
> +			arm_trbe_remove_coresight_cpu(drvdata, cpu);
> +	}
>   	free_percpu(drvdata->cpudata);
>   	return 0;
>   }
> @@ -1406,12 +1415,8 @@ static int arm_trbe_cpu_teardown(unsigned int cpu, struct hlist_node *node)
>   {
>   	struct trbe_drvdata *drvdata = hlist_entry_safe(node, struct trbe_drvdata, hotplug_node);
>   
> -	if (cpumask_test_cpu(cpu, &drvdata->supported_cpus)) {
> -		struct trbe_cpudata *cpudata = per_cpu_ptr(drvdata->cpudata, cpu);
> -
> -		disable_percpu_irq(drvdata->irq);
> -		trbe_reset_local(cpudata);
> -	}
> +	if (cpumask_test_cpu(cpu, &drvdata->supported_cpus))
> +		arm_trbe_disable_cpu(drvdata);
>   	return 0;
>   }
>
hejunhao Aug. 14, 2023, 1:32 p.m. UTC | #2 
Hi Suzuki


On 2023/8/14 18:34, Suzuki K Poulose wrote:
> Hi Junhao
>
> On 14/08/2023 10:38, Junhao He wrote:
>> smp_call_function_single() will allocate an IPI interrupt vector to
>> the target processor and send a function call request to the interrupt
>> vector. After the target processor receives the IPI interrupt, it will
>> execute arm_trbe_remove_coresight_cpu() call request in the interrupt
>> handler.
>>
>> According to the device_unregister() stack information, if other process
>> is useing the device, the down_write() may sleep, and trigger deadlocks
>> or unexpected errors.
>>
>>    arm_trbe_remove_coresight_cpu
>>      coresight_unregister
>>        device_unregister
>>          device_del
>>            kobject_del
>>              __kobject_del
>>                sysfs_remove_dir
>>                  kernfs_remove
>>                    down_write ---------> it may sleep
>>
>> Add a helper arm_trbe_disable_cpu() to disable TRBE precpu irq and reset
>> per TRBE.
>> Simply call arm_trbe_remove_coresight_cpu() directly without useing the
>> smp_call_function_single(), which is the same as registering the TRBE
>> coresight device.
>>
>> Fixes: 3fbf7f011f24 ("coresight: sink: Add TRBE driver")
>> Signed-off-by: Junhao He <hejunhao3@huawei.com>
>> ---
>>   drivers/hwtracing/coresight/coresight-trbe.c | 35 +++++++++++---------
>>   1 file changed, 20 insertions(+), 15 deletions(-)
>>
>> diff --git a/drivers/hwtracing/coresight/coresight-trbe.c 
>> b/drivers/hwtracing/coresight/coresight-trbe.c
>> index 7720619909d6..ce1e6f537b8d 100644
>> --- a/drivers/hwtracing/coresight/coresight-trbe.c
>> +++ b/drivers/hwtracing/coresight/coresight-trbe.c
>> @@ -1225,6 +1225,17 @@ static void arm_trbe_enable_cpu(void *info)
>>       enable_percpu_irq(drvdata->irq, IRQ_TYPE_NONE);
>>   }
>>   +static void arm_trbe_disable_cpu(void *info)
>> +{
>> +    struct trbe_drvdata *drvdata = info;
>> +    struct trbe_cpudata *cpudata = this_cpu_ptr(drvdata->cpudata);
>> +
>> +    disable_percpu_irq(drvdata->irq);
>> +    trbe_reset_local(cpudata);
>> +    cpudata->drvdata = NULL;
>> +}
>> +
>> +
>>   static void arm_trbe_register_coresight_cpu(struct trbe_drvdata 
>> *drvdata, int cpu)
>>   {
>>       struct trbe_cpudata *cpudata = per_cpu_ptr(drvdata->cpudata, cpu);
>> @@ -1326,18 +1337,12 @@ static void arm_trbe_probe_cpu(void *info)
>>       cpumask_clear_cpu(cpu, &drvdata->supported_cpus);
>>   }
>>   -static void arm_trbe_remove_coresight_cpu(void *info)
>> +static void arm_trbe_remove_coresight_cpu(struct trbe_drvdata 
>> *drvdata, int cpu)
>>   {
>> -    int cpu = smp_processor_id();
>> -    struct trbe_drvdata *drvdata = info;
>> -    struct trbe_cpudata *cpudata = per_cpu_ptr(drvdata->cpudata, cpu);
>>       struct coresight_device *trbe_csdev = 
>> coresight_get_percpu_sink(cpu);
>>   -    disable_percpu_irq(drvdata->irq);
>> -    trbe_reset_local(cpudata);
>>       if (trbe_csdev) {
>>           coresight_unregister(trbe_csdev);
>> -        cpudata->drvdata = NULL;
>>           coresight_set_percpu_sink(cpu, NULL);
>
> I am a bit concerned about "resetting" the sink from a different CPU.
> Could we instead, schedule a delayed work to unregister the trbe_csdev?

Yes, I will try to do that.
Sorry for my following questions.
As you mean, do we need to take the same care when setting the percpu sink
in the register trbe_csdev ?

Best regards,
Junhao.

>
>
>>       }
>>   }
>> @@ -1366,8 +1371,12 @@ static int arm_trbe_remove_coresight(struct 
>> trbe_drvdata *drvdata)
>>   {
>>       int cpu;
>>   -    for_each_cpu(cpu, &drvdata->supported_cpus)
>> -        smp_call_function_single(cpu, arm_trbe_remove_coresight_cpu, 
>> drvdata, 1);
>> +    for_each_cpu(cpu, &drvdata->supported_cpus) {
>> +        if (cpumask_test_cpu(cpu, &drvdata->supported_cpus))
>> +            smp_call_function_single(cpu, arm_trbe_disable_cpu, 
>> drvdata, 1);
>> +        if (cpumask_test_cpu(cpu, &drvdata->supported_cpus))
>> +            arm_trbe_remove_coresight_cpu(drvdata, cpu);
>> +    }
>>       free_percpu(drvdata->cpudata);
>>       return 0;
>>   }
>> @@ -1406,12 +1415,8 @@ static int arm_trbe_cpu_teardown(unsigned int 
>> cpu, struct hlist_node *node)
>>   {
>>       struct trbe_drvdata *drvdata = hlist_entry_safe(node, struct 
>> trbe_drvdata, hotplug_node);
>>   -    if (cpumask_test_cpu(cpu, &drvdata->supported_cpus)) {
>> -        struct trbe_cpudata *cpudata = per_cpu_ptr(drvdata->cpudata, 
>> cpu);
>> -
>> -        disable_percpu_irq(drvdata->irq);
>> -        trbe_reset_local(cpudata);
>> -    }
>> +    if (cpumask_test_cpu(cpu, &drvdata->supported_cpus))
>> +        arm_trbe_disable_cpu(drvdata);
>>       return 0;
>>   }
>
>
> .
>
Suzuki K Poulose Aug. 14, 2023, 10:57 p.m. UTC | #3 
On 14/08/2023 14:32, hejunhao wrote:
> Hi Suzuki
> 
> 
> On 2023/8/14 18:34, Suzuki K Poulose wrote:
>> Hi Junhao
>>
>> On 14/08/2023 10:38, Junhao He wrote:
>>> smp_call_function_single() will allocate an IPI interrupt vector to
>>> the target processor and send a function call request to the interrupt
>>> vector. After the target processor receives the IPI interrupt, it will
>>> execute arm_trbe_remove_coresight_cpu() call request in the interrupt
>>> handler.
>>>
>>> According to the device_unregister() stack information, if other process
>>> is useing the device, the down_write() may sleep, and trigger deadlocks
>>> or unexpected errors.
>>>
>>>    arm_trbe_remove_coresight_cpu
>>>      coresight_unregister
>>>        device_unregister
>>>          device_del
>>>            kobject_del
>>>              __kobject_del
>>>                sysfs_remove_dir
>>>                  kernfs_remove
>>>                    down_write ---------> it may sleep
>>>
>>> Add a helper arm_trbe_disable_cpu() to disable TRBE precpu irq and reset
>>> per TRBE.
>>> Simply call arm_trbe_remove_coresight_cpu() directly without useing the
>>> smp_call_function_single(), which is the same as registering the TRBE
>>> coresight device.
>>>
>>> Fixes: 3fbf7f011f24 ("coresight: sink: Add TRBE driver")
>>> Signed-off-by: Junhao He <hejunhao3@huawei.com>
>>> ---
>>>   drivers/hwtracing/coresight/coresight-trbe.c | 35 +++++++++++---------
>>>   1 file changed, 20 insertions(+), 15 deletions(-)
>>>
>>> diff --git a/drivers/hwtracing/coresight/coresight-trbe.c 
>>> b/drivers/hwtracing/coresight/coresight-trbe.c
>>> index 7720619909d6..ce1e6f537b8d 100644
>>> --- a/drivers/hwtracing/coresight/coresight-trbe.c
>>> +++ b/drivers/hwtracing/coresight/coresight-trbe.c
>>> @@ -1225,6 +1225,17 @@ static void arm_trbe_enable_cpu(void *info)
>>>       enable_percpu_irq(drvdata->irq, IRQ_TYPE_NONE);
>>>   }
>>>   +static void arm_trbe_disable_cpu(void *info)
>>> +{
>>> +    struct trbe_drvdata *drvdata = info;
>>> +    struct trbe_cpudata *cpudata = this_cpu_ptr(drvdata->cpudata);
>>> +
>>> +    disable_percpu_irq(drvdata->irq);
>>> +    trbe_reset_local(cpudata);
>>> +    cpudata->drvdata = NULL;
>>> +}
>>> +
>>> +
>>>   static void arm_trbe_register_coresight_cpu(struct trbe_drvdata 
>>> *drvdata, int cpu)
>>>   {
>>>       struct trbe_cpudata *cpudata = per_cpu_ptr(drvdata->cpudata, cpu);
>>> @@ -1326,18 +1337,12 @@ static void arm_trbe_probe_cpu(void *info)
>>>       cpumask_clear_cpu(cpu, &drvdata->supported_cpus);
>>>   }
>>>   -static void arm_trbe_remove_coresight_cpu(void *info)
>>> +static void arm_trbe_remove_coresight_cpu(struct trbe_drvdata 
>>> *drvdata, int cpu)
>>>   {
>>> -    int cpu = smp_processor_id();
>>> -    struct trbe_drvdata *drvdata = info;
>>> -    struct trbe_cpudata *cpudata = per_cpu_ptr(drvdata->cpudata, cpu);
>>>       struct coresight_device *trbe_csdev = 
>>> coresight_get_percpu_sink(cpu);
>>>   -    disable_percpu_irq(drvdata->irq);
>>> -    trbe_reset_local(cpudata);
>>>       if (trbe_csdev) {
>>>           coresight_unregister(trbe_csdev);
>>> -        cpudata->drvdata = NULL;
>>>           coresight_set_percpu_sink(cpu, NULL);
>>
>> I am a bit concerned about "resetting" the sink from a different CPU.
>> Could we instead, schedule a delayed work to unregister the trbe_csdev?
> 
> Yes, I will try to do that.
> Sorry for my following questions.
> As you mean, do we need to take the same care when setting the percpu sink
> in the register trbe_csdev ?

Apologies, having taken another look, we set the percpu_sink for
a cpu outside smp_call_function(). So, I think your patch is fine.


> 
> Best regards,
> Junhao.
> 
>>
>>
>>>       }
>>>   }
>>> @@ -1366,8 +1371,12 @@ static int arm_trbe_remove_coresight(struct 
>>> trbe_drvdata *drvdata)
>>>   {
>>>       int cpu;
>>>   -    for_each_cpu(cpu, &drvdata->supported_cpus)
>>> -        smp_call_function_single(cpu, arm_trbe_remove_coresight_cpu, 
>>> drvdata, 1);
>>> +    for_each_cpu(cpu, &drvdata->supported_cpus) {
>>> +        if (cpumask_test_cpu(cpu, &drvdata->supported_cpus))
>>> +            smp_call_function_single(cpu, arm_trbe_disable_cpu, 
>>> drvdata, 1);
>>> +        if (cpumask_test_cpu(cpu, &drvdata->supported_cpus))
>>> +            arm_trbe_remove_coresight_cpu(drvdata, cpu);

Do we need to test the cpu here in both places ? We already check that
in the loop entry. The reason why we repeat the check during the probe,
is to skip any CPUs that may have a TRBE not accessible.

Suzuki


>>> +    }
>>>       free_percpu(drvdata->cpudata);
>>>       return 0;
>>>   }
>>> @@ -1406,12 +1415,8 @@ static int arm_trbe_cpu_teardown(unsigned int 
>>> cpu, struct hlist_node *node)
>>>   {
>>>       struct trbe_drvdata *drvdata = hlist_entry_safe(node, struct 
>>> trbe_drvdata, hotplug_node);
>>>   -    if (cpumask_test_cpu(cpu, &drvdata->supported_cpus)) {
>>> -        struct trbe_cpudata *cpudata = per_cpu_ptr(drvdata->cpudata, 
>>> cpu);
>>> -
>>> -        disable_percpu_irq(drvdata->irq);
>>> -        trbe_reset_local(cpudata);
>>> -    }
>>> +    if (cpumask_test_cpu(cpu, &drvdata->supported_cpus))
>>> +        arm_trbe_disable_cpu(drvdata);
>>>       return 0;
>>>   }
>>
>>
>> .
>>
>
hejunhao Aug. 15, 2023, 11:40 a.m. UTC | #4 
Hi Suzuki


On 2023/8/15 6:57, Suzuki K Poulose wrote:
> On 14/08/2023 14:32, hejunhao wrote:
>> Hi Suzuki
>>
>>
>> On 2023/8/14 18:34, Suzuki K Poulose wrote:
>>> Hi Junhao
>>>
>>> On 14/08/2023 10:38, Junhao He wrote:
>>>> smp_call_function_single() will allocate an IPI interrupt vector to
>>>> the target processor and send a function call request to the interrupt
>>>> vector. After the target processor receives the IPI interrupt, it will
>>>> execute arm_trbe_remove_coresight_cpu() call request in the interrupt
>>>> handler.
>>>>
>>>> According to the device_unregister() stack information, if other 
>>>> process
>>>> is useing the device, the down_write() may sleep, and trigger 
>>>> deadlocks
>>>> or unexpected errors.
>>>>
>>>>    arm_trbe_remove_coresight_cpu
>>>>      coresight_unregister
>>>>        device_unregister
>>>>          device_del
>>>>            kobject_del
>>>>              __kobject_del
>>>>                sysfs_remove_dir
>>>>                  kernfs_remove
>>>>                    down_write ---------> it may sleep
>>>>
>>>> Add a helper arm_trbe_disable_cpu() to disable TRBE precpu irq and 
>>>> reset
>>>> per TRBE.
>>>> Simply call arm_trbe_remove_coresight_cpu() directly without useing 
>>>> the
>>>> smp_call_function_single(), which is the same as registering the TRBE
>>>> coresight device.
>>>>
>>>> Fixes: 3fbf7f011f24 ("coresight: sink: Add TRBE driver")
>>>> Signed-off-by: Junhao He <hejunhao3@huawei.com>
>>>> ---
>>>>   drivers/hwtracing/coresight/coresight-trbe.c | 35 
>>>> +++++++++++---------
>>>>   1 file changed, 20 insertions(+), 15 deletions(-)
>>>>
>>>> diff --git a/drivers/hwtracing/coresight/coresight-trbe.c 
>>>> b/drivers/hwtracing/coresight/coresight-trbe.c
>>>> index 7720619909d6..ce1e6f537b8d 100644
>>>> --- a/drivers/hwtracing/coresight/coresight-trbe.c
>>>> +++ b/drivers/hwtracing/coresight/coresight-trbe.c
>>>> @@ -1225,6 +1225,17 @@ static void arm_trbe_enable_cpu(void *info)
>>>>       enable_percpu_irq(drvdata->irq, IRQ_TYPE_NONE);
>>>>   }
>>>>   +static void arm_trbe_disable_cpu(void *info)
>>>> +{
>>>> +    struct trbe_drvdata *drvdata = info;
>>>> +    struct trbe_cpudata *cpudata = this_cpu_ptr(drvdata->cpudata);
>>>> +
>>>> +    disable_percpu_irq(drvdata->irq);
>>>> +    trbe_reset_local(cpudata);
>>>> +    cpudata->drvdata = NULL;
>>>> +}
>>>> +
>>>> +
>>>>   static void arm_trbe_register_coresight_cpu(struct trbe_drvdata 
>>>> *drvdata, int cpu)
>>>>   {
>>>>       struct trbe_cpudata *cpudata = per_cpu_ptr(drvdata->cpudata, 
>>>> cpu);
>>>> @@ -1326,18 +1337,12 @@ static void arm_trbe_probe_cpu(void *info)
>>>>       cpumask_clear_cpu(cpu, &drvdata->supported_cpus);
>>>>   }
>>>>   -static void arm_trbe_remove_coresight_cpu(void *info)
>>>> +static void arm_trbe_remove_coresight_cpu(struct trbe_drvdata 
>>>> *drvdata, int cpu)
>>>>   {
>>>> -    int cpu = smp_processor_id();
>>>> -    struct trbe_drvdata *drvdata = info;
>>>> -    struct trbe_cpudata *cpudata = per_cpu_ptr(drvdata->cpudata, 
>>>> cpu);
>>>>       struct coresight_device *trbe_csdev = 
>>>> coresight_get_percpu_sink(cpu);
>>>>   -    disable_percpu_irq(drvdata->irq);
>>>> -    trbe_reset_local(cpudata);
>>>>       if (trbe_csdev) {
>>>>           coresight_unregister(trbe_csdev);
>>>> -        cpudata->drvdata = NULL;
>>>>           coresight_set_percpu_sink(cpu, NULL);
>>>
>>> I am a bit concerned about "resetting" the sink from a different CPU.
>>> Could we instead, schedule a delayed work to unregister the trbe_csdev?
>>
>> Yes, I will try to do that.
>> Sorry for my following questions.
>> As you mean, do we need to take the same care when setting the percpu 
>> sink
>> in the register trbe_csdev ?
>
> Apologies, having taken another look, we set the percpu_sink for
> a cpu outside smp_call_function(). So, I think your patch is fine.
>
>
>>
>> Best regards,
>> Junhao.
>>
>>>
>>>
>>>>       }
>>>>   }
>>>> @@ -1366,8 +1371,12 @@ static int arm_trbe_remove_coresight(struct 
>>>> trbe_drvdata *drvdata)
>>>>   {
>>>>       int cpu;
>>>>   -    for_each_cpu(cpu, &drvdata->supported_cpus)
>>>> -        smp_call_function_single(cpu, 
>>>> arm_trbe_remove_coresight_cpu, drvdata, 1);
>>>> +    for_each_cpu(cpu, &drvdata->supported_cpus) {
>>>> +        if (cpumask_test_cpu(cpu, &drvdata->supported_cpus))
>>>> +            smp_call_function_single(cpu, arm_trbe_disable_cpu, 
>>>> drvdata, 1);
>>>> +        if (cpumask_test_cpu(cpu, &drvdata->supported_cpus))
>>>> +            arm_trbe_remove_coresight_cpu(drvdata, cpu);
>
> Do we need to test the cpu here in both places ? We already check that
> in the loop entry. The reason why we repeat the check during the probe,
> is to skip any CPUs that may have a TRBE not accessible.
>
> Suzuki
>

Ok, Will fix in next version.

Best regards,
Junhao.

>
>>>> +    }
>>>>       free_percpu(drvdata->cpudata);
>>>>       return 0;
>>>>   }
>>>> @@ -1406,12 +1415,8 @@ static int arm_trbe_cpu_teardown(unsigned 
>>>> int cpu, struct hlist_node *node)
>>>>   {
>>>>       struct trbe_drvdata *drvdata = hlist_entry_safe(node, struct 
>>>> trbe_drvdata, hotplug_node);
>>>>   -    if (cpumask_test_cpu(cpu, &drvdata->supported_cpus)) {
>>>> -        struct trbe_cpudata *cpudata = 
>>>> per_cpu_ptr(drvdata->cpudata, cpu);
>>>> -
>>>> -        disable_percpu_irq(drvdata->irq);
>>>> -        trbe_reset_local(cpudata);
>>>> -    }
>>>> +    if (cpumask_test_cpu(cpu, &drvdata->supported_cpus))
>>>> +        arm_trbe_disable_cpu(drvdata);
>>>>       return 0;
>>>>   }
>>>
>>>
>>> .
>>>
>>
>
>
> .
>
diff mbox series

Patch

diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c
index 7720619909d6..ce1e6f537b8d 100644
--- a/drivers/hwtracing/coresight/coresight-trbe.c
+++ b/drivers/hwtracing/coresight/coresight-trbe.c
@@ -1225,6 +1225,17 @@  static void arm_trbe_enable_cpu(void *info)
 	enable_percpu_irq(drvdata->irq, IRQ_TYPE_NONE);
 }
 
+static void arm_trbe_disable_cpu(void *info)
+{
+	struct trbe_drvdata *drvdata = info;
+	struct trbe_cpudata *cpudata = this_cpu_ptr(drvdata->cpudata);
+
+	disable_percpu_irq(drvdata->irq);
+	trbe_reset_local(cpudata);
+	cpudata->drvdata = NULL;
+}
+
+
 static void arm_trbe_register_coresight_cpu(struct trbe_drvdata *drvdata, int cpu)
 {
 	struct trbe_cpudata *cpudata = per_cpu_ptr(drvdata->cpudata, cpu);
@@ -1326,18 +1337,12 @@  static void arm_trbe_probe_cpu(void *info)
 	cpumask_clear_cpu(cpu, &drvdata->supported_cpus);
 }
 
-static void arm_trbe_remove_coresight_cpu(void *info)
+static void arm_trbe_remove_coresight_cpu(struct trbe_drvdata *drvdata, int cpu)
 {
-	int cpu = smp_processor_id();
-	struct trbe_drvdata *drvdata = info;
-	struct trbe_cpudata *cpudata = per_cpu_ptr(drvdata->cpudata, cpu);
 	struct coresight_device *trbe_csdev = coresight_get_percpu_sink(cpu);
 
-	disable_percpu_irq(drvdata->irq);
-	trbe_reset_local(cpudata);
 	if (trbe_csdev) {
 		coresight_unregister(trbe_csdev);
-		cpudata->drvdata = NULL;
 		coresight_set_percpu_sink(cpu, NULL);
 	}
 }
@@ -1366,8 +1371,12 @@  static int arm_trbe_remove_coresight(struct trbe_drvdata *drvdata)
 {
 	int cpu;
 
-	for_each_cpu(cpu, &drvdata->supported_cpus)
-		smp_call_function_single(cpu, arm_trbe_remove_coresight_cpu, drvdata, 1);
+	for_each_cpu(cpu, &drvdata->supported_cpus) {
+		if (cpumask_test_cpu(cpu, &drvdata->supported_cpus))
+			smp_call_function_single(cpu, arm_trbe_disable_cpu, drvdata, 1);
+		if (cpumask_test_cpu(cpu, &drvdata->supported_cpus))
+			arm_trbe_remove_coresight_cpu(drvdata, cpu);
+	}
 	free_percpu(drvdata->cpudata);
 	return 0;
 }
@@ -1406,12 +1415,8 @@  static int arm_trbe_cpu_teardown(unsigned int cpu, struct hlist_node *node)
 {
 	struct trbe_drvdata *drvdata = hlist_entry_safe(node, struct trbe_drvdata, hotplug_node);
 
-	if (cpumask_test_cpu(cpu, &drvdata->supported_cpus)) {
-		struct trbe_cpudata *cpudata = per_cpu_ptr(drvdata->cpudata, cpu);
-
-		disable_percpu_irq(drvdata->irq);
-		trbe_reset_local(cpudata);
-	}
+	if (cpumask_test_cpu(cpu, &drvdata->supported_cpus))
+		arm_trbe_disable_cpu(drvdata);
 	return 0;
 }