[ros-diffs] [gvg] 13227: Keep usermode stack 4-byte aligned

[gvg at svn.reactos.com]

Keep usermode stack 4-byte aligned
Modified: trunk/reactos/ntoskrnl/ps/w32call.c
  _____  

Modified: trunk/reactos/ntoskrnl/ps/w32call.c
--- trunk/reactos/ntoskrnl/ps/w32call.c	2005-01-23 18:18:08 UTC (rev
13226)
+++ trunk/reactos/ntoskrnl/ps/w32call.c	2005-01-23 20:48:19 UTC (rev
13227)
@@ -292,7 +292,8 @@

   memcpy((char*)NewStack + StackSize - sizeof(KTRAP_FRAME) -
sizeof(FX_SAVE_AREA),
          Thread->Tcb.TrapFrame, sizeof(KTRAP_FRAME) - (4 *
sizeof(DWORD)));
   NewFrame = (PKTRAP_FRAME)((char*)NewStack + StackSize -
sizeof(KTRAP_FRAME) - sizeof(FX_SAVE_AREA));
-  NewFrame->Esp -= (ArgumentLength + (4 * sizeof(ULONG)));
+  /* We need the stack pointer to remain 4-byte aligned */
+  NewFrame->Esp -= (((ArgumentLength + 3) & (~ 0x3)) + (4 *
sizeof(ULONG)));
   NewFrame->Eip = (ULONG)LdrpGetSystemDllCallbackDispatcher();
   UserEsp = (PULONG)NewFrame->Esp;
   UserEsp[0] = 0;     /* Return address. */
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