SysCall: Added NumberOfCalls to USER_SPACE_DRIVER.

MdeModulePkg/Core/Dxe/DxeMain.h

@@ -238,6 +238,7 @@ typedef struct {
   VOID        *UserSpaceDriver;
   UINTN       UserPageTable;
   UINTN       UserStackTop;
+  UINT8       NumberOfCalls;
   LIST_ENTRY  Link;
 } USER_SPACE_DRIVER;
 

MdeModulePkg/Core/Dxe/Image/Image.c

@@ -1743,6 +1743,7 @@ CoreStartImage (
         UserDriver->UserSpaceDriver = (VOID *)Image->EntryPoint;
         UserDriver->UserPageTable   = Image->UserPageTable;
         UserDriver->UserStackTop    = Image->UserStackTop;
+        UserDriver->NumberOfCalls   = 0;
 
         InsertTailList (&gUserSpaceDriversHead, &UserDriver->Link);
 

MdeModulePkg/Core/Dxe/SysCall/BootServices.c

@@ -548,6 +548,7 @@ CallBootService (
         NewDriver->UserSpaceDriver = UserArgList[Index + 1];
         NewDriver->UserPageTable   = UserDriver->UserPageTable;
         NewDriver->UserStackTop    = UserDriver->UserStackTop;
+        NewDriver->NumberOfCalls   = 0;
 
         InsertTailList (&gUserSpaceDriversHead, &NewDriver->Link);
       }

MdeModulePkg/Core/Dxe/SysCall/SupportedProtocols.c

@@ -8,6 +8,8 @@
 #include "DxeMain.h"
 #include "SupportedProtocols.h"
 
+#define MAX_CALL 1
+
 LIST_ENTRY gUserSpaceDriversHead = INITIALIZE_LIST_HEAD_VARIABLE (gUserSpaceDriversHead);
 
 EFI_STATUS
@@ -33,6 +35,10 @@ GoToRing3 (
   EFI_PHYSICAL_ADDRESS  Ring3Pages;
   UINT32                PagesNumber;
 
+  if (UserDriver->NumberOfCalls > MAX_CALL) {
+    return EFI_OUT_OF_RESOURCES;
+  }
+
   PagesNumber = (UINT32)EFI_SIZE_TO_PAGES (sizeof (RING3_CALL_DATA) + Number * sizeof (UINTN));
 
   Status = CoreAllocatePages (
@@ -61,11 +67,15 @@ GoToRing3 (
   // TODO: Allocate new stacks (only for EFI_FILE_PROTOCOL instances?),
   // because UserDriver can be interrupted and interrupt handler may call the same UserDriver again.
   //
+  ++UserDriver->NumberOfCalls;
+
   Status = CallRing3 (
              Input,
              UserDriver->UserStackTop
              );
 
+  --UserDriver->NumberOfCalls;
+
   CoreFreePages (Ring3Pages, PagesNumber);
 
   return Status;
@@ -754,6 +764,7 @@ CoreFileOpen (
   NewDriver->CoreWrapper     = NewFile;
   NewDriver->UserPageTable   = UserDriver->UserPageTable;
   NewDriver->UserStackTop    = UserDriver->UserStackTop;
+  NewDriver->NumberOfCalls   = 0;
 
   AllowSupervisorAccessToUserMemory ();
   NewDriver->UserSpaceDriver = *Ring3NewHandle;
@@ -855,6 +866,7 @@ CoreSimpleFileSystemOpenVolume (
   NewDriver->CoreWrapper     = File;
   NewDriver->UserPageTable   = UserDriver->UserPageTable;
   NewDriver->UserStackTop    = UserDriver->UserStackTop;
+  NewDriver->NumberOfCalls   = 0;
 
   AllowSupervisorAccessToUserMemory ();
   NewDriver->UserSpaceDriver = *Ring3Root;