Namespace: Add support to allow overriding objects.

This patch adds an "NamespaceOverride" flag in ACPI_WALK_STATE, and allows namespace objects to be overridden when this flag is set. Lv Zheng. Signed-off-by: Lv Zheng <lv.zheng@intel.com>
acpica · Jun 1, 2015 · 6084e34 · 6084e34
1 parent 6005294
commit 6084e34
Show file tree

Hide file tree

Showing 5 changed files with 45 additions and 7 deletions.
diff --git a/source/components/dispatcher/dswload.c b/source/components/dispatcher/dswload.c
@@ -397,9 +397,18 @@ AcpiDsLoad1BeginOp (
         if ((WalkState->Opcode != AML_SCOPE_OP) &&
             (!(WalkState->ParseFlags & ACPI_PARSE_DEFERRED_OP)))
         {
-            Flags |= ACPI_NS_ERROR_IF_FOUND;
-            ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, "[%s] Cannot already exist\n",
-                    AcpiUtGetTypeName (ObjectType)));
+            if (WalkState->NamespaceOverride)
+            {
+                Flags |= ACPI_NS_OVERRIDE_IF_FOUND;
+                ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, "[%s] Override allowed\n",
+                        AcpiUtGetTypeName (ObjectType)));
+            }
+            else
+            {
+                Flags |= ACPI_NS_ERROR_IF_FOUND;
+                ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, "[%s] Cannot already exist\n",
+                        AcpiUtGetTypeName (ObjectType)));
+            }
         }
         else
         {

diff --git a/source/components/namespace/nsaccess.c b/source/components/namespace/nsaccess.c
@@ -391,7 +391,9 @@ AcpiNsLookup (
         return_ACPI_STATUS (AE_BAD_PARAMETER);
     }
 
-    LocalFlags = Flags & ~(ACPI_NS_ERROR_IF_FOUND | ACPI_NS_SEARCH_PARENT);
+    LocalFlags = Flags &
+        ~(ACPI_NS_ERROR_IF_FOUND | ACPI_NS_OVERRIDE_IF_FOUND |
+          ACPI_NS_SEARCH_PARENT);
     *ReturnNode = ACPI_ENTRY_NOT_FOUND;
     AcpiGbl_NsLookupCount++;
 
@@ -643,6 +645,13 @@ AcpiNsLookup (
             {
                 LocalFlags |= ACPI_NS_ERROR_IF_FOUND;
             }
+
+            /* Set override flag according to caller */
+
+            if (Flags & ACPI_NS_OVERRIDE_IF_FOUND)
+            {
+                LocalFlags |= ACPI_NS_OVERRIDE_IF_FOUND;
+            }
         }
 
         /* Extract one ACPI name from the front of the pathname */

diff --git a/source/components/namespace/nssearch.c b/source/components/namespace/nssearch.c
@@ -410,10 +410,28 @@ AcpiNsSearchAndEnter (
          * If we found it AND the request specifies that a find is an error,
          * return the error
          */
-        if ((Status == AE_OK) &&
-            (Flags & ACPI_NS_ERROR_IF_FOUND))
+        if (Status == AE_OK)
         {
-            Status = AE_ALREADY_EXISTS;
+            /* The node was found in the namespace */
+
+            /*
+             * If the namespace override feature is enabled for this node,
+             * delete any existing node. This can only happen during the
+             * boot stage, thus it is safe to remove the node here.
+             */
+            if (Flags & ACPI_NS_OVERRIDE_IF_FOUND)
+            {
+                AcpiNsDeleteChildren (*ReturnNode);
+                AcpiNsRemoveNode (*ReturnNode);
+                *ReturnNode = ACPI_ENTRY_NOT_FOUND;
+            }
+
+            /* Return an error if we don't expect to find the object */
+
+            else if (Flags & ACPI_NS_ERROR_IF_FOUND)
+            {
+                Status = AE_ALREADY_EXISTS;
+            }
         }
 
 #ifdef ACPI_ASL_COMPILER

diff --git a/source/include/acnamesp.h b/source/include/acnamesp.h
@@ -139,6 +139,7 @@
 #define ACPI_NS_PREFIX_IS_SCOPE     0x10
 #define ACPI_NS_EXTERNAL            0x20
 #define ACPI_NS_TEMPORARY           0x40
+#define ACPI_NS_OVERRIDE_IF_FOUND   0x80
 
 /* Flags for AcpiNsWalkNamespace */
 

diff --git a/source/include/acstruct.h b/source/include/acstruct.h
@@ -157,6 +157,7 @@ typedef struct acpi_walk_state
     UINT8                           ReturnUsed;
     UINT8                           ScopeDepth;
     UINT8                           PassNumber;         /* Parse pass during table load */
+    BOOLEAN                         NamespaceOverride;  /* Override existing objects */
     UINT8                           ResultSize;         /* Total elements for the result stack */
     UINT8                           ResultCount;        /* Current number of occupied elements of result stack */
     UINT32                          AmlOffset;