[ros-arm-bringup] 44842: NMI Support Patch 2: [HAL]: Simplify IDT write-protection handling (always make it R/W and restore it to previous state). [HAL]: Avoid two superflous TLB flushes.

Author: ros-arm-bringup
Date: Fri Jan  1 00:56:40 2010
New Revision: 44842

URL: http://svn.reactos.org/svn/reactos?rev=44842&view=rev
Log:
NMI Support Patch 2:
    [HAL]: Simplify IDT write-protection handling (always make it R/W and restore it to previous state).
    [HAL]: Avoid two superflous TLB flushes.

Modified:
    trunk/reactos/hal/halx86/generic/bios.c

Modified: trunk/reactos/hal/halx86/generic/bios.c
URL: http://svn.reactos.org/svn/reactos/trunk/reactos/hal/halx86/generic/bios.c?r...
==============================================================================
--- trunk/reactos/hal/halx86/generic/bios.c [iso-8859-1] (original)
+++ trunk/reactos/hal/halx86/generic/bios.c [iso-8859-1] Fri Jan  1 00:56:40 2010
@@ -254,18 +254,8 @@
      * the cmpxchg8b lock errata. Unprotect them here so we can set our custom
      * invalid op-code handler.
      */
-    if (KeGetCurrentPrcb()->CpuType == 5)
-    {
-        /* Get the PTE and check if it is has been write protected yet  */
-        IdtPte = GetPteAddress(((PKIPCR)KeGetPcr())->IDT);
-        if (IdtPte->Write == 0)
-        {
-            /* Remove the protection and flush the TLB */
-            IdtPte->Write = 1;
-            __writecr3(__readcr3());
-            RestoreWriteProtection = TRUE;
-        }
-    }
+    IdtPte = GetPteAddress(((PKIPCR)KeGetPcr())->IDT);
+    RestoreWriteProtection = IdtPte->Write;

/* Use special invalid opcode and GPF trap handlers */
     HalpSwitchToRealModeTrapHandlers();
@@ -279,15 +269,9 @@
     /* Restore kernel trap handlers */
     HalpRestoreTrapHandlers();

-    /* Check if we removed the write protection before */
-    if (RestoreWriteProtection)
-    {
-        /* Get the PTE, restore the write protection and flush the TLB */
-        IdtPte = GetPteAddress(((PKIPCR)KeGetPcr())->IDT);
-        IdtPte->Write = 0;
-        __writecr3(__readcr3());
-    }
-    
+    /* Restore write permission */
+    IdtPte->Write = RestoreWriteProtection;
+
     /* Restore TSS and IOPM */
     HalpRestoreIoPermissionsAndTask();