Disassembler: Do not unconditionally remove temporary names

Change the Switch disassembly code to check if the conversion can be done before removing temporary (_T_x) names. Prevents invalid disassembly of AML created by older compilers (circa 2005). Link: https://bugs.acpica.org/show_bug.cgi?id=1358 Link: https://bugs.acpica.org/show_bug.cgi?id=1360 Reported-by: racerrehabman@gmail.com Signed-off-by: David E. Box <david.e.box@linux.intel.com>
acpica · Feb 24, 2017 · c46f496 · c46f496
1 parent bb1a602
commit c46f496
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Showing 2 changed files with 30 additions and 14 deletions.
diff --git a/source/components/disassembler/dmopcode.c b/source/components/disassembler/dmopcode.c
@@ -142,7 +142,8 @@ AcpiDmPromoteSubtree (
 
 static BOOLEAN
 AcpiDmIsSwitchBlock (
-    ACPI_PARSE_OBJECT       *Op);
+    ACPI_PARSE_OBJECT       *Op,
+    char                    *Temp);
 
 static BOOLEAN
 AcpiDmIsCaseBlock (
@@ -1049,7 +1050,7 @@ AcpiDmDisassembleOneOp (
 
     case AML_WHILE_OP:
 
-        if (AcpiDmIsSwitchBlock(Op))
+        if (Op->Common.DisasmOpcode == ACPI_DASM_SWITCH)
         {
             AcpiOsPrintf ("%s", "Switch");
             break;
@@ -1327,18 +1328,21 @@ AcpiDmPromoteSubtree (
  *
  * PARAMETERS:  Op              - Object to be examined
  *
- * RETURN:      TRUE if object is a temporary (_T_x) name
+ * RETURN:      TRUE if object is a temporary (_T_x) name for a matching While
+ *              loop that can be converted to a Switch.
  *
- * DESCRIPTION: Determine if an object is a temporary name and ignore it.
- *              Temporary names are only used for Switch statements. This
- *              function depends on this restriced usage.
+ * DESCRIPTION: _T_X objects are only used for Switch statements. If a temporary
+ *              name exists, search the siblings for a matching While (One) loop
+ *              that can be converted to a Switch. Return TRUE if a match was
+ *              found, FALSE otherwise.
  *
  ******************************************************************************/
 
 BOOLEAN
 AcpiDmIsTempName (
     ACPI_PARSE_OBJECT       *Op)
 {
+    ACPI_PARSE_OBJECT       *CurrentOp;
     char                    *Temp;
 
     if (Op->Common.AmlOpcode != AML_NAME_OP)
@@ -1354,11 +1358,21 @@ AcpiDmIsTempName (
         return (FALSE);
     }
 
-    /* Ignore Op */
+    CurrentOp = Op->Common.Next;
+    while (CurrentOp)
+    {
+        if (CurrentOp->Common.AmlOpcode == AML_WHILE_OP &&
+            AcpiDmIsSwitchBlock(CurrentOp, Temp))
+        {
+            Op->Common.DisasmFlags |= ACPI_PARSEOP_IGNORE;
+            CurrentOp->Common.DisasmOpcode = ACPI_DASM_SWITCH;
 
-    Op->Common.DisasmFlags |= ACPI_PARSEOP_IGNORE;
+            return (TRUE);
+        }
+        CurrentOp = CurrentOp->Common.Next;
+    }
 
-    return (TRUE);
+    return (FALSE);
 }
 
 /*******************************************************************************
@@ -1394,7 +1408,8 @@ AcpiDmIsTempName (
 
 static BOOLEAN
 AcpiDmIsSwitchBlock (
-    ACPI_PARSE_OBJECT       *Op)
+    ACPI_PARSE_OBJECT       *Op,
+    char                    *Temp)
 {
     ACPI_PARSE_OBJECT       *OneOp;
     ACPI_PARSE_OBJECT       *StoreOp;
@@ -1427,7 +1442,7 @@ AcpiDmIsSwitchBlock (
         return (FALSE);
     }
 
-    if (strncmp((char *)(NamePathOp->Common.Aml), "_T_", 3))
+    if (strncmp((char *)(NamePathOp->Common.Aml), Temp, 4))
     {
         return (FALSE);
     }

diff --git a/source/include/aclocal.h b/source/include/aclocal.h
@@ -1009,9 +1009,10 @@ typedef union acpi_parse_value
 #define ACPI_DASM_LNOT_SUFFIX           0x09        /* End  of a LNotEqual (etc.) pair of opcodes */
 #define ACPI_DASM_HID_STRING            0x0A        /* String is a _HID or _CID */
 #define ACPI_DASM_IGNORE_SINGLE         0x0B        /* Ignore the opcode but not it's children */
-#define ACPI_DASM_SWITCH_PREDICATE      0x0C        /* Object is a predicate for a Switch or Case block */
-#define ACPI_DASM_CASE                  0x0D        /* If/Else is a Case in a Switch/Case block */
-#define ACPI_DASM_DEFAULT               0x0E        /* Else is a Default in a Switch/Case block */
+#define ACPI_DASM_SWITCH                0x0C        /* While is a Switch */
+#define ACPI_DASM_SWITCH_PREDICATE      0x0D        /* Object is a predicate for a Switch or Case block */
+#define ACPI_DASM_CASE                  0x0E        /* If/Else is a Case in a Switch/Case block */
+#define ACPI_DASM_DEFAULT               0x0F        /* Else is a Default in a Switch/Case block */
 
 /*
  * Generic operation (for example:  If, While, Store)