From f61b9c911357950e7753674dc8ced623335a0bcd Mon Sep 17 00:00:00 2001
From: Sir Richard <sir_richard@svn.reactos.org>
Date: Sun, 10 Jan 2010 14:32:19 +0000
Subject: [PATCH] [NTOS]: Implement KiAdjustEsp0 in C. [NTOS]: Temporarily
 remove FPU save/restore instructions since they seem to be smashing the stack
 and breaking boot.

svn path=/trunk/; revision=45027
---
 reactos/ntoskrnl/ke/i386/ctxswitch.S | 35 ----------------------------
 reactos/ntoskrnl/ke/i386/exp.c       | 34 +++++++++++++++++++++++++++
 reactos/ntoskrnl/ke/i386/traphdlr.c  | 14 +++++------
 3 files changed, 41 insertions(+), 42 deletions(-)

diff --git a/reactos/ntoskrnl/ke/i386/ctxswitch.S b/reactos/ntoskrnl/ke/i386/ctxswitch.S
index 2e025b3445a..3ac799145dc 100644
--- a/reactos/ntoskrnl/ke/i386/ctxswitch.S
+++ b/reactos/ntoskrnl/ke/i386/ctxswitch.S
@@ -807,41 +807,6 @@ NoNextThread:
 #endif
 .endfunc
 
-.globl _Ki386AdjustEsp0@4
-.func Ki386AdjustEsp0@4
-_Ki386AdjustEsp0@4:
-
-    /* Get the current thread */
-    mov eax, [fs:KPCR_CURRENT_THREAD]
-
-    /* Get trap frame and stack */
-    mov edx, [esp+4]
-    mov eax, [eax+KTHREAD_INITIAL_STACK]
-
-    /* Check if V86 */
-    test dword ptr [edx+KTRAP_FRAME_EFLAGS], EFLAGS_V86_MASK
-    jnz 1f
-
-    /* Bias the stack */
-    sub eax, KTRAP_FRAME_V86_GS - KTRAP_FRAME_SS
-
-1:
-    /* Skip FX Save Area */
-    sub eax, SIZEOF_FX_SAVE_AREA
-
-    /* Disable interrupts */
-    pushf
-    cli
-
-    /* Adjust ESP0 */
-    mov edx, [fs:KPCR_TSS]
-    mov ss:[edx+KTSS_ESP0], eax
-
-    /* Enable interrupts and return */
-    popf
-    ret 4
-.endfunc
-
 .globl _KiSwapProcess@8
 .func KiSwapProcess@8
 _KiSwapProcess@8:
diff --git a/reactos/ntoskrnl/ke/i386/exp.c b/reactos/ntoskrnl/ke/i386/exp.c
index c529a170f90..57cbb1e5f9f 100644
--- a/reactos/ntoskrnl/ke/i386/exp.c
+++ b/reactos/ntoskrnl/ke/i386/exp.c
@@ -305,6 +305,40 @@ KiTagWordFnsaveToFxsave(USHORT TagWord)
     return FxTagWord;
 }
 
+VOID
+NTAPI
+Ki386AdjustEsp0(IN PKTRAP_FRAME TrapFrame)
+{
+    PKTHREAD Thread;
+    ULONG_PTR Stack;
+    ULONG EFlags;
+    
+    /* Get the current thread's stack */
+    Thread = KeGetCurrentThread();
+    Stack = (ULONG_PTR)Thread->InitialStack;
+    
+    /* Check if we are in V8086 mode */
+    if (!(TrapFrame->EFlags & EFLAGS_V86_MASK))
+    {
+        /* Bias the stack for the V86 segments */
+        Stack -= (FIELD_OFFSET(KTRAP_FRAME, V86Gs) -
+                  FIELD_OFFSET(KTRAP_FRAME, HardwareSegSs));
+    }
+    
+    /* Bias the stack for the FPU area */
+    Stack -= sizeof(FX_SAVE_AREA);
+    
+    /* Disable interrupts */
+    EFlags = __readeflags();
+    _disable();
+    
+    /* Set new ESP0 value in the TSS */
+    KeGetPcr()->TSS->Esp0 = Stack;
+    
+    /* Restore old interrupt state */
+    __writeeflags(EFlags);
+}
+
 VOID
 NTAPI
 KeContextToTrapFrame(IN PCONTEXT Context,
diff --git a/reactos/ntoskrnl/ke/i386/traphdlr.c b/reactos/ntoskrnl/ke/i386/traphdlr.c
index 274790ad6e9..7802955d1e1 100644
--- a/reactos/ntoskrnl/ke/i386/traphdlr.c
+++ b/reactos/ntoskrnl/ke/i386/traphdlr.c
@@ -270,11 +270,11 @@ KiNpxHandler(IN PKTRAP_FRAME TrapFrame,
         SaveArea->Cr0NpxState |= CR0_TS;
         
         /* Only valid if it happened during a restore */
-        if ((PVOID)TrapFrame->Eip == FrRestore)
+        //if ((PVOID)TrapFrame->Eip == FrRestore)
         {
             /* It did, so just skip the instruction */
-            TrapFrame->Eip += 3; /* sizeof(FRSTOR) */
-            KiEoiHelper(TrapFrame);
+            //TrapFrame->Eip += 3; /* sizeof(FRSTOR) */
+            //KiEoiHelper(TrapFrame);
         }
     }
 
@@ -287,7 +287,7 @@ KiNpxHandler(IN PKTRAP_FRAME TrapFrame,
         __writecr0(Cr0);
 
         /* Save FPU state */
-        Ke386SaveFpuState(SaveArea);
+        //Ke386SaveFpuState(SaveArea);
 
         /* Mark CR0 state dirty */
         Cr0 |= NPX_STATE_NOT_LOADED;
@@ -588,14 +588,14 @@ KiTrap7Handler(IN PKTRAP_FRAME TrapFrame)
                 NpxSaveArea = KiGetThreadNpxArea(NpxThread);
                 
                 /* Save FPU state */
-                Ke386SaveFpuState(NpxSaveArea);
+                //Ke386SaveFpuState(NpxSaveArea);
 
                 /* Update NPX state */
                 Thread->NpxState = NPX_STATE_NOT_LOADED;
            }
        
             /* Load FPU state */
-            Ke386LoadFpuState(SaveArea);
+            //Ke386LoadFpuState(SaveArea);
         
             /* Update NPX state */
             Thread->NpxState = NPX_STATE_LOADED;
@@ -925,7 +925,7 @@ KiTrap19Handler(IN PKTRAP_FRAME TrapFrame)
     __writecr0(Cr0);
     
     /* Save FPU state */
-    Ke386SaveFpuState(SaveArea);
+    //Ke386SaveFpuState(SaveArea);
     
     /* Mark CR0 state dirty */
     Cr0 |= NPX_STATE_NOT_LOADED;