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ACPI: property: Disregard references in data-only subnode lists

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Data-only subnode links following the ACPI data subnode GUID in a _DSD
package are expected to point to named objects returning _DSD-equivalent
packages.  If a reference to such an object is used in the target field
of any of those links, that object will be evaluated in place (as a
named object) and its return data will be embedded in the outer _DSD
package.

For this reason, it is not expected to see a subnode link with the
target field containing a local reference (that would mean pointing
to a device or another object that cannot be evaluated in place and
therefore cannot return a _DSD-equivalent package).

Accordingly, simplify the code parsing data-only subnode links to
simply print a message when it encounters a local reference in the
target field of one of those links.

Moreover, since acpi_nondev_subnode_data_ok() would only have one
caller after the change above, fold it into that caller.

Link: https://lore.kernel.org/linux-acpi/CAJZ5v0jVeSrDO6hrZhKgRZrH=FpGD4vNUjFD8hV9WwN9TLHjzQ@mail.gmail.com/
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Tested-by: Sakari Ailus <sakari.ailus@linux.intel.com>
This commit is contained in:
Rafael J. Wysocki 2025-09-15 20:23:28 +02:00
parent d0759b1098
commit d06118fe9b
1 changed files with 23 additions and 30 deletions
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53
drivers/acpi/property.c
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@ -124,14 +124,23 @@ static bool acpi_nondev_subnode_extract(union acpi_object *desc,
return false;
}
static bool acpi_nondev_subnode_data_ok(acpi_handle handle,
const union acpi_object *link,
struct list_head *list,
struct fwnode_handle *parent)
static bool acpi_nondev_subnode_ok(acpi_handle scope,
const union acpi_object *link,
struct list_head *list,
struct fwnode_handle *parent)
{
struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER };
acpi_handle handle;
acpi_status status;
if (!scope)
return false;
status = acpi_get_handle(scope, link->package.elements[1].string.pointer,
&handle);
if (ACPI_FAILURE(status))
return false;
status = acpi_evaluate_object_typed(handle, NULL, NULL, &buf,
ACPI_TYPE_PACKAGE);
if (ACPI_FAILURE(status))
@ -145,25 +154,6 @@ static bool acpi_nondev_subnode_data_ok(acpi_handle handle,
return false;
}
static bool acpi_nondev_subnode_ok(acpi_handle scope,
const union acpi_object *link,
struct list_head *list,
struct fwnode_handle *parent)
{
acpi_handle handle;
acpi_status status;
if (!scope)
return false;
status = acpi_get_handle(scope, link->package.elements[1].string.pointer,
&handle);
if (ACPI_FAILURE(status))
return false;
return acpi_nondev_subnode_data_ok(handle, link, list, parent);
}
static bool acpi_add_nondev_subnodes(acpi_handle scope,
union acpi_object *links,
struct list_head *list,
@ -174,7 +164,6 @@ static bool acpi_add_nondev_subnodes(acpi_handle scope,
for (i = 0; i < links->package.count; i++) {
union acpi_object *link, *desc;
acpi_handle handle;
bool result;
link = &links->package.elements[i];
@ -186,22 +175,26 @@ static bool acpi_add_nondev_subnodes(acpi_handle scope,
if (link->package.elements[0].type != ACPI_TYPE_STRING)
continue;
/* The second one may be a string, a reference or a package. */
/* The second one may be a string or a package. */
switch (link->package.elements[1].type) {
case ACPI_TYPE_STRING:
result = acpi_nondev_subnode_ok(scope, link, list,
parent);
break;
case ACPI_TYPE_LOCAL_REFERENCE:
handle = link->package.elements[1].reference.handle;
result = acpi_nondev_subnode_data_ok(handle, link, list,
parent);
break;
case ACPI_TYPE_PACKAGE:
desc = &link->package.elements[1];
result = acpi_nondev_subnode_extract(desc, NULL, link,
list, parent);
break;
case ACPI_TYPE_LOCAL_REFERENCE:
/*
* It is not expected to see any local references in
* the links package because referencing a named object
* should cause it to be evaluated in place.
*/
acpi_handle_info(scope, "subnode %s: Unexpected reference\n",
link->package.elements[0].string.pointer);
fallthrough;
default:
result = false;
break;