ACPICA: Fix implementation of AML BreakPoint operator (break to debugger)

The AML BreakPoint opcode will now cause a break into the AML
debugger if it is present/configured. This matches the expected
behavior per the ACPI specification. Previously, only a message
was output.
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/acpi/acpica/dsopcode.c

@@ -1386,14 +1386,19 @@ acpi_ds_exec_end_control_op(struct acpi_walk_state * walk_state,
 
 	case AML_BREAK_POINT_OP:
 
-		/* Call up to the OS service layer to handle this */
-
-		status =
-		    acpi_os_signal(ACPI_SIGNAL_BREAKPOINT,
-				   "Executed AML Breakpoint opcode");
+		/*
+		 * Set the single-step flag. This will cause the debugger (if present)
+		 * to break to the console within the AML debugger at the start of the
+		 * next AML instruction.
+		 */
+		ACPI_DEBUGGER_EXEC(acpi_gbl_cm_single_step = TRUE);
+		ACPI_DEBUGGER_EXEC(acpi_os_printf
+				   ("**break** Executed AML BreakPoint opcode\n"));
 
-		/* If and when it returns, all done. */
+		/* Call to the OSL in case OS wants a piece of the action */
 
+		status = acpi_os_signal(ACPI_SIGNAL_BREAKPOINT,
+					"Executed AML Breakpoint opcode");
 		break;
 
 	case AML_BREAK_OP: