ACPICA: Disassembler: Enhance resource descriptor detection

ACPICA commit ba5020b2dbe1538e4ccd7ac2dfd8843a690c007f

This change enhances the detection of resource descriptors
within a buffer object. For the end_tag opcode, the second byte
is defined to be either a checksum or zero. All known ASL compilers
insert a zero for this byte. The disassembler now ensures this
byte is zero before deciding that a buffer should be disassembled
to a resource descriptor. This helps eliminate incorrect decisions
when attempting to disassemble a buffer to a resource descriptor.

Link: https://github.com/acpica/acpica/commit/ba5020b2
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/acpica/utresrc.c

@@ -474,6 +474,15 @@ acpi_ut_walk_aml_resources(struct acpi_walk_state *walk_state,
 				return_ACPI_STATUS(AE_AML_NO_RESOURCE_END_TAG);
 			}
 
+			/*
+			 * The end_tag opcode must be followed by a zero byte.
+			 * Although this byte is technically defined to be a checksum,
+			 * in practice, all ASL compilers set this byte to zero.
+			 */
+			if (*(aml + 1) != 0) {
+				return_ACPI_STATUS(AE_AML_NO_RESOURCE_END_TAG);
+			}
+
 			/* Return the pointer to the end_tag if requested */
 
 			if (!user_function) {