[PATCH] coresight: etm4x: fix mis-usage of nr_resource in sysfs interface

[PATCH] coresight: etm4x: fix mis-usage of nr_resource in sysfs interface

[Jonathan Zhou]

The member @nr_resource represents how many resource selector pairs,
and the pair 0 is always implemented and reserved.
So let's multiply by 2 when displaying the implemented resource seletors
and resetting the seletor configuration .
And also update the validation of the input @idx.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Shaokun Zhang <zhangshaokun@hisilicon.com>
Cc: lizixian@hisilicon.com
Signed-off-by: Jonathan Zhou <jonathan.zhouwen@huawei.com>
---
 drivers/hwtracing/coresight/coresight-etm4x-sysfs.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
index b673e738bc9a..635b93d20efa 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
@@ -143,8 +143,10 @@ static ssize_t nr_resource_show(struct device *dev,
 {
 	unsigned long val;
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
-
-	val = drvdata->nr_resource;
+	/* @nr_resource represents how many resource selector pairs,
+	 * hence multiply by 2.
+	 */
+	val = 2 * drvdata->nr_resource;
 	return scnprintf(buf, PAGE_SIZE, "%#lx\n", val);
 }
 static DEVICE_ATTR_RO(nr_resource);
@@ -236,7 +238,7 @@ static ssize_t reset_store(struct device *dev,
 	}
 
 	config->res_idx = 0x0;
-	for (i = 0; i < drvdata->nr_resource; i++)
+	for (i = 2; i < 2 * drvdata->nr_resource; i++)
 		config->res_ctrl[i] = 0x0;
 
 	config->ss_idx = 0x0;
@@ -1663,8 +1665,11 @@ static ssize_t res_idx_store(struct device *dev,
 
 	if (kstrtoul(buf, 16, &val))
 		return -EINVAL;
-	/* Resource selector pair 0 is always implemented and reserved */
-	if ((val == 0) || (val >= drvdata->nr_resource))
+	/*
+	 * Resource selector pair 0 is always implemented and reserved,
+	 * namely an idx with 0 and 1 is illegal.
+	 */
+	if ((val == 0) || (val == 1) || (val >= 2 * drvdata->nr_resource))
 		return -EINVAL;
 
 	/*
-- 
1.9.1


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Re: [PATCH] coresight: etm4x: fix mis-usage of nr_resource in sysfs interface

[Mathieu Poirier]

On Wed, Sep 02, 2020 at 03:52:56PM +0800, Jonathan Zhou wrote:
> The member @nr_resource represents how many resource selector pairs,
> and the pair 0 is always implemented and reserved.
> So let's multiply by 2 when displaying the implemented resource seletors
> and resetting the seletor configuration .
> And also update the validation of the input @idx.
> 
> Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
> Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
> Cc: Mike Leach <mike.leach@linaro.org>
> Cc: Shaokun Zhang <zhangshaokun@hisilicon.com>
> Cc: lizixian@hisilicon.com
> Signed-off-by: Jonathan Zhou <jonathan.zhouwen@huawei.com>
> ---
>  drivers/hwtracing/coresight/coresight-etm4x-sysfs.c | 15 ++++++++++-----
>  1 file changed, 10 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
> index b673e738bc9a..635b93d20efa 100644
> --- a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
> +++ b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
> @@ -143,8 +143,10 @@ static ssize_t nr_resource_show(struct device *dev,
>  {
>  	unsigned long val;
>  	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
> -
> -	val = drvdata->nr_resource;
> +	/* @nr_resource represents how many resource selector pairs,
> +	 * hence multiply by 2.

Your comment said it correctly, @nr_resource present the number of _pairs_.  As
such the code is correct and there is no need to multiply by 2.    

> +	 */
> +	val = 2 * drvdata->nr_resource;
>  	return scnprintf(buf, PAGE_SIZE, "%#lx\n", val);
>  }
>  static DEVICE_ATTR_RO(nr_resource);
> @@ -236,7 +238,7 @@ static ssize_t reset_store(struct device *dev,
>  	}
>  
>  	config->res_idx = 0x0;
> -	for (i = 0; i < drvdata->nr_resource; i++)
> +	for (i = 2; i < 2 * drvdata->nr_resource; i++)
>  		config->res_ctrl[i] = 0x0;

This hunk is correct - please send a patch for it.

>  
>  	config->ss_idx = 0x0;
> @@ -1663,8 +1665,11 @@ static ssize_t res_idx_store(struct device *dev,
>  
>  	if (kstrtoul(buf, 16, &val))
>  		return -EINVAL;
> -	/* Resource selector pair 0 is always implemented and reserved */
> -	if ((val == 0) || (val >= drvdata->nr_resource))
> +	/*
> +	 * Resource selector pair 0 is always implemented and reserved,
> +	 * namely an idx with 0 and 1 is illegal.
> +	 */
> +	if ((val == 0) || (val == 1) || (val >= 2 * drvdata->nr_resource))
>  		return -EINVAL;

The index, i.e ->res_idx, represent pairs an not individual resource.

Thanks,
Mathieu

>  
>  	/*
> -- 
> 1.9.1
> 

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Re: [PATCH] coresight: etm4x: fix mis-usage of nr_resource in sysfs interface

[Zhouwen (Jonathan, Turing)]

Hi Mathieu,

Thanks for your review.

在 2020/9/4 1:22, Mathieu Poirier 写道:
> On Wed, Sep 02, 2020 at 03:52:56PM +0800, Jonathan Zhou wrote:
>> The member @nr_resource represents how many resource selector pairs,
>> and the pair 0 is always implemented and reserved.
>> So let's multiply by 2 when displaying the implemented resource seletors
>> and resetting the seletor configuration .
>> And also update the validation of the input @idx.
>>
>> Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
>> Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
>> Cc: Mike Leach <mike.leach@linaro.org>
>> Cc: Shaokun Zhang <zhangshaokun@hisilicon.com>
>> Cc: lizixian@hisilicon.com
>> Signed-off-by: Jonathan Zhou <jonathan.zhouwen@huawei.com>
>> ---
>>   drivers/hwtracing/coresight/coresight-etm4x-sysfs.c | 15 ++++++++++-----
>>   1 file changed, 10 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
>> index b673e738bc9a..635b93d20efa 100644
>> --- a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
>> +++ b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
>> @@ -143,8 +143,10 @@ static ssize_t nr_resource_show(struct device *dev,
>>   {
>>   	unsigned long val;
>>   	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
>> -
>> -	val = drvdata->nr_resource;
>> +	/* @nr_resource represents how many resource selector pairs,
>> +	 * hence multiply by 2.
> 
> Your comment said it correctly, @nr_resource present the number of _pairs_.  As
> such the code is correct and there is no need to multiply by 2.
> 

Sorry for not mentioned the reason of modified this. From the function 
@res_ctrl_store, we can see that only one individual resource selector 
can be accessed via the ->res_idx. Therefore, it may be better to show 
the number of individual resource selectors.

>> +	 */
>> +	val = 2 * drvdata->nr_resource;
>>   	return scnprintf(buf, PAGE_SIZE, "%#lx\n", val);
>>   }
>>   static DEVICE_ATTR_RO(nr_resource);
>> @@ -236,7 +238,7 @@ static ssize_t reset_store(struct device *dev,
>>   	}
>>   
>>   	config->res_idx = 0x0;
>> -	for (i = 0; i < drvdata->nr_resource; i++)
>> +	for (i = 2; i < 2 * drvdata->nr_resource; i++)
>>   		config->res_ctrl[i] = 0x0;
> 
> This hunk is correct - please send a patch for it.

Ok.

> 
>>   
>>   	config->ss_idx = 0x0;
>> @@ -1663,8 +1665,11 @@ static ssize_t res_idx_store(struct device *dev,
>>   
>>   	if (kstrtoul(buf, 16, &val))
>>   		return -EINVAL;
>> -	/* Resource selector pair 0 is always implemented and reserved */
>> -	if ((val == 0) || (val >= drvdata->nr_resource))
>> +	/*
>> +	 * Resource selector pair 0 is always implemented and reserved,
>> +	 * namely an idx with 0 and 1 is illegal.
>> +	 */
>> +	if ((val == 0) || (val == 1) || (val >= 2 * drvdata->nr_resource))
>>   		return -EINVAL;
> 
> The index, i.e ->res_idx, represent pairs an not individual resource.
 >
> Thanks,
> Mathieu
> 

If we want all of the ->res_ctrl accessable, the ->res_idx should 
represent individual resource. That's the reason.

Best regards.

Jonathan.

>>   
>>   	/*
>> -- 
>> 1.9.1
>>
> .
> 

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Re: [PATCH] coresight: etm4x: fix mis-usage of nr_resource in sysfs interface

[Mathieu Poirier]

On Fri, Sep 04, 2020 at 06:08:46PM +0800, Zhouwen (Jonathan, Turing) wrote:
> 
> Hi Mathieu,
> 
> Thanks for your review.
> 
> 在 2020/9/4 1:22, Mathieu Poirier 写道:
> > On Wed, Sep 02, 2020 at 03:52:56PM +0800, Jonathan Zhou wrote:
> > > The member @nr_resource represents how many resource selector pairs,
> > > and the pair 0 is always implemented and reserved.
> > > So let's multiply by 2 when displaying the implemented resource seletors
> > > and resetting the seletor configuration .
> > > And also update the validation of the input @idx.
> > > 
> > > Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
> > > Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
> > > Cc: Mike Leach <mike.leach@linaro.org>
> > > Cc: Shaokun Zhang <zhangshaokun@hisilicon.com>
> > > Cc: lizixian@hisilicon.com
> > > Signed-off-by: Jonathan Zhou <jonathan.zhouwen@huawei.com>
> > > ---
> > >   drivers/hwtracing/coresight/coresight-etm4x-sysfs.c | 15 ++++++++++-----
> > >   1 file changed, 10 insertions(+), 5 deletions(-)
> > > 
> > > diff --git a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
> > > index b673e738bc9a..635b93d20efa 100644
> > > --- a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
> > > +++ b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
> > > @@ -143,8 +143,10 @@ static ssize_t nr_resource_show(struct device *dev,
> > >   {
> > >   	unsigned long val;
> > >   	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
> > > -
> > > -	val = drvdata->nr_resource;
> > > +	/* @nr_resource represents how many resource selector pairs,
> > > +	 * hence multiply by 2.
> > 
> > Your comment said it correctly, @nr_resource present the number of _pairs_.  As
> > such the code is correct and there is no need to multiply by 2.
> > 
> 
> Sorry for not mentioned the reason of modified this. From the function
> @res_ctrl_store, we can see that only one individual resource selector can
> be accessed via the ->res_idx. Therefore, it may be better to show the
> number of individual resource selectors.

The end result does not change, i.e this entry represent the number of pairs
available on the system.

> 
> > > +	 */
> > > +	val = 2 * drvdata->nr_resource;
> > >   	return scnprintf(buf, PAGE_SIZE, "%#lx\n", val);
> > >   }
> > >   static DEVICE_ATTR_RO(nr_resource);
> > > @@ -236,7 +238,7 @@ static ssize_t reset_store(struct device *dev,
> > >   	}
> > >   	config->res_idx = 0x0;
> > > -	for (i = 0; i < drvdata->nr_resource; i++)
> > > +	for (i = 2; i < 2 * drvdata->nr_resource; i++)
> > >   		config->res_ctrl[i] = 0x0;
> > 
> > This hunk is correct - please send a patch for it.
> 
> Ok.
> 
> > 
> > >   	config->ss_idx = 0x0;
> > > @@ -1663,8 +1665,11 @@ static ssize_t res_idx_store(struct device *dev,
> > >   	if (kstrtoul(buf, 16, &val))
> > >   		return -EINVAL;
> > > -	/* Resource selector pair 0 is always implemented and reserved */
> > > -	if ((val == 0) || (val >= drvdata->nr_resource))
> > > +	/*
> > > +	 * Resource selector pair 0 is always implemented and reserved,
> > > +	 * namely an idx with 0 and 1 is illegal.
> > > +	 */
> > > +	if ((val == 0) || (val == 1) || (val >= 2 * drvdata->nr_resource))
> > >   		return -EINVAL;
> > 
> > The index, i.e ->res_idx, represent pairs an not individual resource.
> >
> > Thanks,
> > Mathieu
> > 
> 
> If we want all of the ->res_ctrl accessable, the ->res_idx should represent
> individual resource. That's the reason.

I see your point now.  I think the above condition should be simplified:

        if ((val < 2) || (val >= 2 * drvdata->nr_resource))

> 
> Best regards.
> 
> Jonathan.
> 
> > >   	/*
> > > -- 
> > > 1.9.1
> > > 
> > .
> > 

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Re: [PATCH] coresight: etm4x: fix mis-usage of nr_resource in sysfs interface

[Jonathan Zhou]

Hi Mathieu,
Thanks for reply.

On 09/09/2020 01:35, Mathieu Poirier wrote:
> On Fri, Sep 04, 2020 at 06:08:46PM +0800, Zhouwen (Jonathan, Turing) wrote:
>>
>> Hi Mathieu,
>>
>> Thanks for your review.
>>
>> 在 2020/9/4 1:22, Mathieu Poirier 写道:
>>> On Wed, Sep 02, 2020 at 03:52:56PM +0800, Jonathan Zhou wrote:
>>>> The member @nr_resource represents how many resource selector pairs,
>>>> and the pair 0 is always implemented and reserved.
>>>> So let's multiply by 2 when displaying the implemented resource seletors
>>>> and resetting the seletor configuration .
>>>> And also update the validation of the input @idx.
>>>>
>>>> Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
>>>> Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
>>>> Cc: Mike Leach <mike.leach@linaro.org>
>>>> Cc: Shaokun Zhang <zhangshaokun@hisilicon.com>
>>>> Cc: lizixian@hisilicon.com
>>>> Signed-off-by: Jonathan Zhou <jonathan.zhouwen@huawei.com>
>>>> ---
>>>>   drivers/hwtracing/coresight/coresight-etm4x-sysfs.c | 15 ++++++++++-----
>>>>   1 file changed, 10 insertions(+), 5 deletions(-)
>>>>
>>>> diff --git a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
>>>> index b673e738bc9a..635b93d20efa 100644
>>>> --- a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
>>>> +++ b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
>>>> @@ -143,8 +143,10 @@ static ssize_t nr_resource_show(struct device *dev,
>>>>   {
>>>>   	unsigned long val;
>>>>   	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
>>>> -
>>>> -	val = drvdata->nr_resource;
>>>> +	/* @nr_resource represents how many resource selector pairs,
>>>> +	 * hence multiply by 2.
>>>
>>> Your comment said it correctly, @nr_resource present the number of _pairs_.  As
>>> such the code is correct and there is no need to multiply by 2.
>>>
>>
>> Sorry for not mentioned the reason of modified this. From the function
>> @res_ctrl_store, we can see that only one individual resource selector can
>> be accessed via the ->res_idx. Therefore, it may be better to show the
>> number of individual resource selectors.
> 
> The end result does not change, i.e this entry represent the number of pairs
> available on the system.
>It's all right. I will keep it no change.

>>
>>>> +	 */
>>>> +	val = 2 * drvdata->nr_resource;
>>>>   	return scnprintf(buf, PAGE_SIZE, "%#lx\n", val);
>>>>   }
>>>>   static DEVICE_ATTR_RO(nr_resource);
>>>> @@ -236,7 +238,7 @@ static ssize_t reset_store(struct device *dev,
>>>>   	}
>>>>   	config->res_idx = 0x0;
>>>> -	for (i = 0; i < drvdata->nr_resource; i++)
>>>> +	for (i = 2; i < 2 * drvdata->nr_resource; i++)
>>>>   		config->res_ctrl[i] = 0x0;
>>>
>>> This hunk is correct - please send a patch for it.
>>
>> Ok.
>>
>>>
>>>>   	config->ss_idx = 0x0;
>>>> @@ -1663,8 +1665,11 @@ static ssize_t res_idx_store(struct device *dev,
>>>>   	if (kstrtoul(buf, 16, &val))
>>>>   		return -EINVAL;
>>>> -	/* Resource selector pair 0 is always implemented and reserved */
>>>> -	if ((val == 0) || (val >= drvdata->nr_resource))
>>>> +	/*
>>>> +	 * Resource selector pair 0 is always implemented and reserved,
>>>> +	 * namely an idx with 0 and 1 is illegal.
>>>> +	 */
>>>> +	if ((val == 0) || (val == 1) || (val >= 2 * drvdata->nr_resource))
>>>>   		return -EINVAL;
>>>
>>> The index, i.e ->res_idx, represent pairs an not individual resource.
>>>
>>> Thanks,
>>> Mathieu
>>>
>>
>> If we want all of the ->res_ctrl accessable, the ->res_idx should represent
>> individual resource. That's the reason.
> 
> I see your point now.  I think the above condition should be simplified:
> 
>         if ((val < 2) || (val >= 2 * drvdata->nr_resource))
> 
You are right. I will do this.

Thanks.

>>
>> Best regards.
>>
>> Jonathan.
>>
>>>>   	/*
>>>> -- 
>>>> 1.9.1
>>>>
>>> .
>>>
> .
> 


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