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

From: Armin Wolf
Date: Wed Feb 07 2024 - 15:20:32 EST


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@xxxxxx>
---
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