diff mbox series

platform/x86: wmi: Make input buffer madatory when evaulating methods

Message ID 20240207202012.3506-1-W_Armin@gmx.de
State New
Headers
Series platform/x86: wmi: Make input buffer madatory when evaulating methods |

Commit Message

Armin Wolf Feb. 7, 2024, 8:20 p.m. UTC 
  The ACPI-WMI specification declares that a WMxx control method takes
3 arguments: instance, method id and argument buffer. This is also
the case even when the underlying WMI method does not have any
input arguments.

So if a WMI driver evaluates a WMI method without passing an input
buffer, ACPICA will log a warning complaining that the third argument
is missing.

Prevent this by checking that a input buffer was passed, and return
an error if this was not the case.

Tested on a Asus PRIME B650-Plus.

Signed-off-by: Armin Wolf <W_Armin@gmx.de>
---
 drivers/platform/x86/wmi.c | 21 ++++++++++-----------
 1 file changed, 10 insertions(+), 11 deletions(-)

--
2.39.2

Comments

Kuppuswamy Sathyanarayanan Feb. 8, 2024, 2:41 a.m. UTC | #1 
On 2/7/24 12:20 PM, Armin Wolf wrote:
> The ACPI-WMI specification declares that a WMxx control method takes
> 3 arguments: instance, method id and argument buffer. This is also
> the case even when the underlying WMI method does not have any
> input arguments.

It would be better if you include specification version and section
title for reference.

>
> So if a WMI driver evaluates a WMI method without passing an input
> buffer, ACPICA will log a warning complaining that the third argument
> is missing.

I assume it is a compile warning. Can you copy the warning message?

>
> Prevent this by checking that a input buffer was passed, and return
> an error if this was not the case.
>
> Tested on a Asus PRIME B650-Plus.
>
> Signed-off-by: Armin Wolf <W_Armin@gmx.de>
> ---


With above fixed,

Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>

>  drivers/platform/x86/wmi.c | 21 ++++++++++-----------
>  1 file changed, 10 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c
> index 63906fdd0abf..f9e23d491dd9 100644
> --- a/drivers/platform/x86/wmi.c
> +++ b/drivers/platform/x86/wmi.c
> @@ -296,7 +296,7 @@ EXPORT_SYMBOL_GPL(wmidev_instance_count);
>   * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
>   * @instance: Instance index
>   * @method_id: Method ID to call
> - * @in: Buffer containing input for the method call
> + * @in: Mandatory buffer containing input for the method call
>   * @out: Empty buffer to return the method results
>   *
>   * Call an ACPI-WMI method, the caller must free @out.
> @@ -326,7 +326,7 @@ EXPORT_SYMBOL_GPL(wmi_evaluate_method);
>   * @wdev: A wmi bus device from a driver
>   * @instance: Instance index
>   * @method_id: Method ID to call
> - * @in: Buffer containing input for the method call
> + * @in: Mandatory buffer containing input for the method call
>   * @out: Empty buffer to return the method results
>   *
>   * Call an ACPI-WMI method, the caller must free @out.
> @@ -347,26 +347,25 @@ acpi_status wmidev_evaluate_method(struct wmi_device *wdev, u8 instance, u32 met
>  	block = &wblock->gblock;
>  	handle = wblock->acpi_device->handle;
>
> +	if (!in)
> +		return AE_BAD_DATA;
> +
>  	if (!(block->flags & ACPI_WMI_METHOD))
>  		return AE_BAD_DATA;
>
>  	if (block->instance_count <= instance)
>  		return AE_BAD_PARAMETER;
>
> -	input.count = 2;
> +	input.count = 3;
>  	input.pointer = params;
> +
>  	params[0].type = ACPI_TYPE_INTEGER;
>  	params[0].integer.value = instance;
>  	params[1].type = ACPI_TYPE_INTEGER;
>  	params[1].integer.value = method_id;
> -
> -	if (in) {
> -		input.count = 3;
> -
> -		params[2].type = get_param_acpi_type(wblock);
> -		params[2].buffer.length = in->length;
> -		params[2].buffer.pointer = in->pointer;
> -	}
> +	params[2].type = get_param_acpi_type(wblock);
> +	params[2].buffer.length = in->length;
> +	params[2].buffer.pointer = in->pointer;
>
>  	get_acpi_method_name(wblock, 'M', method);
>
> --
> 2.39.2
>
>
Armin Wolf Feb. 8, 2024, 6:22 p.m. UTC | #2 
Am 08.02.24 um 03:41 schrieb Kuppuswamy Sathyanarayanan:

> On 2/7/24 12:20 PM, Armin Wolf wrote:
>> The ACPI-WMI specification declares that a WMxx control method takes
>> 3 arguments: instance, method id and argument buffer. This is also
>> the case even when the underlying WMI method does not have any
>> input arguments.
> It would be better if you include specification version and section
> title for reference.

The ACPI-WMI specification is not part of the ACPI specification. It
consists of a single whitepaper published by Microsoft:

https://github.com/microsoft/Windows-driver-samples/blob/main/wmi/wmiacpi/wmi-acpi.htm

The section describing the ACPI control methods is called
"ACPI Control Method Naming Conventions and Functionality for Windows 2000 Instrumentation".

I do not thing that mentioning this in the commit message would be of any use.

>> So if a WMI driver evaluates a WMI method without passing an input
>> buffer, ACPICA will log a warning complaining that the third argument
>> is missing.
> I assume it is a compile warning. Can you copy the warning message?

Its not a compiler warning.

The ACPI control method is being evaluated at runtime, so the warning message
will also be generated at runtime (when interpreting the AML bytecode).

Thanks,
Armin Wolf

>> Prevent this by checking that a input buffer was passed, and return
>> an error if this was not the case.
>>
>> Tested on a Asus PRIME B650-Plus.
>>
>> Signed-off-by: Armin Wolf <W_Armin@gmx.de>
>> ---
>
> With above fixed,
>
> Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
>
>>   drivers/platform/x86/wmi.c | 21 ++++++++++-----------
>>   1 file changed, 10 insertions(+), 11 deletions(-)
>>
>> diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c
>> index 63906fdd0abf..f9e23d491dd9 100644
>> --- a/drivers/platform/x86/wmi.c
>> +++ b/drivers/platform/x86/wmi.c
>> @@ -296,7 +296,7 @@ EXPORT_SYMBOL_GPL(wmidev_instance_count);
>>    * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
>>    * @instance: Instance index
>>    * @method_id: Method ID to call
>> - * @in: Buffer containing input for the method call
>> + * @in: Mandatory buffer containing input for the method call
>>    * @out: Empty buffer to return the method results
>>    *
>>    * Call an ACPI-WMI method, the caller must free @out.
>> @@ -326,7 +326,7 @@ EXPORT_SYMBOL_GPL(wmi_evaluate_method);
>>    * @wdev: A wmi bus device from a driver
>>    * @instance: Instance index
>>    * @method_id: Method ID to call
>> - * @in: Buffer containing input for the method call
>> + * @in: Mandatory buffer containing input for the method call
>>    * @out: Empty buffer to return the method results
>>    *
>>    * Call an ACPI-WMI method, the caller must free @out.
>> @@ -347,26 +347,25 @@ acpi_status wmidev_evaluate_method(struct wmi_device *wdev, u8 instance, u32 met
>>   	block = &wblock->gblock;
>>   	handle = wblock->acpi_device->handle;
>>
>> +	if (!in)
>> +		return AE_BAD_DATA;
>> +
>>   	if (!(block->flags & ACPI_WMI_METHOD))
>>   		return AE_BAD_DATA;
>>
>>   	if (block->instance_count <= instance)
>>   		return AE_BAD_PARAMETER;
>>
>> -	input.count = 2;
>> +	input.count = 3;
>>   	input.pointer = params;
>> +
>>   	params[0].type = ACPI_TYPE_INTEGER;
>>   	params[0].integer.value = instance;
>>   	params[1].type = ACPI_TYPE_INTEGER;
>>   	params[1].integer.value = method_id;
>> -
>> -	if (in) {
>> -		input.count = 3;
>> -
>> -		params[2].type = get_param_acpi_type(wblock);
>> -		params[2].buffer.length = in->length;
>> -		params[2].buffer.pointer = in->pointer;
>> -	}
>> +	params[2].type = get_param_acpi_type(wblock);
>> +	params[2].buffer.length = in->length;
>> +	params[2].buffer.pointer = in->pointer;
>>
>>   	get_acpi_method_name(wblock, 'M', method);
>>
>> --
>> 2.39.2
>>
>>
Kuppuswamy Sathyanarayanan Feb. 8, 2024, 9:24 p.m. UTC | #3 
On 2/8/24 10:22 AM, Armin Wolf wrote:
> Am 08.02.24 um 03:41 schrieb Kuppuswamy Sathyanarayanan:
>
>> On 2/7/24 12:20 PM, Armin Wolf wrote:
>>> The ACPI-WMI specification declares that a WMxx control method takes
>>> 3 arguments: instance, method id and argument buffer. This is also
>>> the case even when the underlying WMI method does not have any
>>> input arguments.
>> It would be better if you include specification version and section
>> title for reference.
>
> The ACPI-WMI specification is not part of the ACPI specification. It
> consists of a single whitepaper published by Microsoft:
>
> https://github.com/microsoft/Windows-driver-samples/blob/main/wmi/wmiacpi/wmi-acpi.htm
>
> The section describing the ACPI control methods is called
> "ACPI Control Method Naming Conventions and Functionality for Windows 2000 Instrumentation".
>
> I do not thing that mentioning this in the commit message would be of any use.

I think it is better to include this detail. But, since it is not a standard specification,
I will let maintainer make this call.

>
>>> So if a WMI driver evaluates a WMI method without passing an input
>>> buffer, ACPICA will log a warning complaining that the third argument
>>> is missing.
>> I assume it is a compile warning. Can you copy the warning message?
>
> Its not a compiler warning.
>
> The ACPI control method is being evaluated at runtime, so the warning message
> will also be generated at runtime (when interpreting the AML bytecode).
>

Got it.

> Thanks,
> Armin Wolf
>
>>> Prevent this by checking that a input buffer was passed, and return
>>> an error if this was not the case.
>>>
>>> Tested on a Asus PRIME B650-Plus.
>>>
>>> Signed-off-by: Armin Wolf <W_Armin@gmx.de>
>>> ---
>>
>> With above fixed,
>>
>> Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
>>
>>>   drivers/platform/x86/wmi.c | 21 ++++++++++-----------
>>>   1 file changed, 10 insertions(+), 11 deletions(-)
>>>
>>> diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c
>>> index 63906fdd0abf..f9e23d491dd9 100644
>>> --- a/drivers/platform/x86/wmi.c
>>> +++ b/drivers/platform/x86/wmi.c
>>> @@ -296,7 +296,7 @@ EXPORT_SYMBOL_GPL(wmidev_instance_count);
>>>    * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
>>>    * @instance: Instance index
>>>    * @method_id: Method ID to call
>>> - * @in: Buffer containing input for the method call
>>> + * @in: Mandatory buffer containing input for the method call
>>>    * @out: Empty buffer to return the method results
>>>    *
>>>    * Call an ACPI-WMI method, the caller must free @out.
>>> @@ -326,7 +326,7 @@ EXPORT_SYMBOL_GPL(wmi_evaluate_method);
>>>    * @wdev: A wmi bus device from a driver
>>>    * @instance: Instance index
>>>    * @method_id: Method ID to call
>>> - * @in: Buffer containing input for the method call
>>> + * @in: Mandatory buffer containing input for the method call
>>>    * @out: Empty buffer to return the method results
>>>    *
>>>    * Call an ACPI-WMI method, the caller must free @out.
>>> @@ -347,26 +347,25 @@ acpi_status wmidev_evaluate_method(struct wmi_device *wdev, u8 instance, u32 met
>>>       block = &wblock->gblock;
>>>       handle = wblock->acpi_device->handle;
>>>
>>> +    if (!in)
>>> +        return AE_BAD_DATA;
>>> +
>>>       if (!(block->flags & ACPI_WMI_METHOD))
>>>           return AE_BAD_DATA;
>>>
>>>       if (block->instance_count <= instance)
>>>           return AE_BAD_PARAMETER;
>>>
>>> -    input.count = 2;
>>> +    input.count = 3;
>>>       input.pointer = params;
>>> +
>>>       params[0].type = ACPI_TYPE_INTEGER;
>>>       params[0].integer.value = instance;
>>>       params[1].type = ACPI_TYPE_INTEGER;
>>>       params[1].integer.value = method_id;
>>> -
>>> -    if (in) {
>>> -        input.count = 3;
>>> -
>>> -        params[2].type = get_param_acpi_type(wblock);
>>> -        params[2].buffer.length = in->length;
>>> -        params[2].buffer.pointer = in->pointer;
>>> -    }
>>> +    params[2].type = get_param_acpi_type(wblock);
>>> +    params[2].buffer.length = in->length;
>>> +    params[2].buffer.pointer = in->pointer;
>>>
>>>       get_acpi_method_name(wblock, 'M', method);
>>>
>>> -- 
>>> 2.39.2
>>>
>>>
>
diff mbox series

Patch

diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c
index 63906fdd0abf..f9e23d491dd9 100644
--- a/drivers/platform/x86/wmi.c
+++ b/drivers/platform/x86/wmi.c
@@ -296,7 +296,7 @@  EXPORT_SYMBOL_GPL(wmidev_instance_count);
  * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
  * @instance: Instance index
  * @method_id: Method ID to call
- * @in: Buffer containing input for the method call
+ * @in: Mandatory buffer containing input for the method call
  * @out: Empty buffer to return the method results
  *
  * Call an ACPI-WMI method, the caller must free @out.
@@ -326,7 +326,7 @@  EXPORT_SYMBOL_GPL(wmi_evaluate_method);
  * @wdev: A wmi bus device from a driver
  * @instance: Instance index
  * @method_id: Method ID to call
- * @in: Buffer containing input for the method call
+ * @in: Mandatory buffer containing input for the method call
  * @out: Empty buffer to return the method results
  *
  * Call an ACPI-WMI method, the caller must free @out.
@@ -347,26 +347,25 @@  acpi_status wmidev_evaluate_method(struct wmi_device *wdev, u8 instance, u32 met
 	block = &wblock->gblock;
 	handle = wblock->acpi_device->handle;

+	if (!in)
+		return AE_BAD_DATA;
+
 	if (!(block->flags & ACPI_WMI_METHOD))
 		return AE_BAD_DATA;

 	if (block->instance_count <= instance)
 		return AE_BAD_PARAMETER;

-	input.count = 2;
+	input.count = 3;
 	input.pointer = params;
+
 	params[0].type = ACPI_TYPE_INTEGER;
 	params[0].integer.value = instance;
 	params[1].type = ACPI_TYPE_INTEGER;
 	params[1].integer.value = method_id;
-
-	if (in) {
-		input.count = 3;
-
-		params[2].type = get_param_acpi_type(wblock);
-		params[2].buffer.length = in->length;
-		params[2].buffer.pointer = in->pointer;
-	}
+	params[2].type = get_param_acpi_type(wblock);
+	params[2].buffer.length = in->length;
+	params[2].buffer.pointer = in->pointer;

 	get_acpi_method_name(wblock, 'M', method);