From 877b413520b8d1156b4faa5100a3ae4fa9d4c085 Mon Sep 17 00:00:00 2001
From: Dmitry Gorbachev <gorbachev@reactos.org>
Date: Tue, 2 Jun 2009 22:14:46 +0000
Subject: [PATCH] Do not crash on software breakpoint in kdb.

svn path=/trunk/; revision=41264
---
 reactos/ntoskrnl/kd/i386/kdmemsup.c | 113 ++++++++++++++++++++++++++--
 1 file changed, 108 insertions(+), 5 deletions(-)

diff --git a/reactos/ntoskrnl/kd/i386/kdmemsup.c b/reactos/ntoskrnl/kd/i386/kdmemsup.c
index 5a3d4b818b8..d0d5fbe8092 100644
--- a/reactos/ntoskrnl/kd/i386/kdmemsup.c
+++ b/reactos/ntoskrnl/kd/i386/kdmemsup.c
@@ -15,16 +15,24 @@
 #define PAGE_TABLE_MASK 0x3ff
 #define BIG_PAGE_SIZE (1<<22)
 #define CR4_PAGE_SIZE_BIT 0x10
-#define PDE_PRESENT_BIT 1
-#define PDE_W_BIT 2
+#define PDE_PRESENT_BIT 0x01
+#define PDE_W_BIT 0x02
+#define PDE_PWT_BIT 0x08
+#define PDE_PCD_BIT 0x10
+#define PDE_ACCESSED_BIT 0x20
+#define PDE_DIRTY_BIT 0x40
 #define PDE_PS_BIT 0x80
 
+#define MI_KDBG_TMP_PAGE_1 (HYPER_SPACE + 0x400000 - PAGE_SIZE)
+#define MI_KDBG_TMP_PAGE_0 (MI_KDBG_TMP_PAGE_1 - PAGE_SIZE)
+
 /* VARIABLES ***************************************************************/
 
-extern ULONG MmGlobalKernelPageDirectory[1024];
 static BOOLEAN KdpPhysAccess = FALSE;
+
+#if 0
+extern ULONG MmGlobalKernelPageDirectory[1024];
 ULONG_PTR IdentityMapAddrHigh, IdentityMapAddrLow;
-extern PFN_TYPE NTAPI MmAllocEarlyPage();
 
 ULONGLONG
 FASTCALL
@@ -66,7 +74,6 @@ KdpPhysRead(ULONG_PTR Addr, LONG Len)
     return Result;
 }
 
-
 VOID
 NTAPI
 KdpPhysWrite(ULONG_PTR Addr, LONG Len, ULONGLONG Value)
@@ -104,6 +111,91 @@ KdpPhysWrite(ULONG_PTR Addr, LONG Len, ULONGLONG Value)
     __invlpg((PVOID)Addr);
 }
 
+#else
+
+static
+ULONG_PTR
+KdpPhysMap(ULONG_PTR PhysAddr, LONG Len)
+{
+    MMPTE TempPte;
+    PMMPTE PointerPte;
+    ULONG_PTR VirtAddr;
+
+    TempPte.u.Long = PDE_PRESENT_BIT | PDE_W_BIT | PDE_PWT_BIT |
+                     PDE_PCD_BIT | PDE_ACCESSED_BIT | PDE_DIRTY_BIT;
+
+    if ((PhysAddr & (PAGE_SIZE - 1)) + Len > PAGE_SIZE)
+    {
+        TempPte.u.Hard.PageFrameNumber = (PhysAddr >> PAGE_SHIFT) + 1;
+        PointerPte = MiAddressToPte(MI_KDBG_TMP_PAGE_1);
+        *PointerPte = TempPte;
+        VirtAddr = (ULONG_PTR)PointerPte << 10;
+        __invlpg((PVOID)VirtAddr);
+    }
+
+    TempPte.u.Hard.PageFrameNumber = PhysAddr >> PAGE_SHIFT;
+    PointerPte = MiAddressToPte(MI_KDBG_TMP_PAGE_0);
+    *PointerPte = TempPte;
+    VirtAddr = (ULONG_PTR)PointerPte << 10;
+    __invlpg((PVOID)VirtAddr);
+
+    return VirtAddr + (PhysAddr & (PAGE_SIZE - 1));
+}
+
+static
+ULONGLONG
+KdpPhysRead(ULONG_PTR PhysAddr, LONG Len)
+{
+    ULONG_PTR Addr;
+    ULONGLONG Result = 0;
+
+    Addr = KdpPhysMap(PhysAddr, Len);
+
+    switch (Len)
+    {
+    case 8:
+        Result = *((PULONGLONG)Addr);
+        break;
+    case 4:
+        Result = *((PULONG)Addr);
+        break;
+    case 2:
+        Result = *((PUSHORT)Addr);
+        break;
+    case 1:
+        Result = *((PUCHAR)Addr);
+        break;
+    }
+
+    return Result;
+}
+
+static
+VOID
+KdpPhysWrite(ULONG_PTR PhysAddr, LONG Len, ULONGLONG Value)
+{
+    ULONG_PTR Addr;
+
+    Addr = KdpPhysMap(PhysAddr, Len);
+
+    switch (Len)
+    {
+    case 8:
+        *((PULONGLONG)Addr) = Value;
+        break;
+    case 4:
+        *((PULONG)Addr) = Value;
+        break;
+    case 2:
+        *((PUSHORT)Addr) = Value;
+        break;
+    case 1:
+        *((PUCHAR)Addr) = Value;
+        break;
+    }
+}
+#endif
+
 BOOLEAN
 NTAPI
 KdpTranslateAddress(ULONG_PTR Addr, PULONG_PTR ResultAddr)
@@ -199,6 +291,7 @@ KdpSafeWriteMemory(ULONG_PTR Addr, LONG Len, ULONGLONG Value)
     return TRUE;
 }
 
+#if 0
 VOID
 NTAPI
 KdpEnableSafeMem()
@@ -245,3 +338,13 @@ KdpEnableSafeMem()
 
     KdpPhysAccess = TRUE;
 }
+
+#else
+
+VOID
+NTAPI
+KdpEnableSafeMem(VOID)
+{
+    KdpPhysAccess = TRUE;
+}
+#endif