ntoskrnl/kd/i386/kdmemsup.c

   1 /*****************************************************************************\
   2  *                                                                           *
   3  *     This file is current kept ONLY for DOCUMENTATION purposes, until      *
   4  *  we are sure that all the functionality (e.g. regarding the "big pages")  *
   5  * are fully present in Mm and in mm/ARM3/mmdbg.c that supersedes this file. *
   6  *                                                                           *
   7 \*****************************************************************************/
   8
   9 /*
  10  * COPYRIGHT:       See COPYING in the top level directory
  11  * PROJECT:         ReactOS Kernel
  12  * FILE:            ntoskrnl/kd/i386/kdmemsup.c
  13  * PURPOSE:         Kernel Debugger Safe Memory Support
  14  *
  15  * PROGRAMMERS:     arty
  16  */
  17
  18 #include <ntoskrnl.h>
  19 #define NDEBUG
  20 #include <debug.h>
  21
  22 #define HIGH_PHYS_MASK 0x80000000
  23 #define PAGE_TABLE_MASK 0x3ff
  24 #define BIG_PAGE_SIZE (1<<22)
  25 #define CR4_PAGE_SIZE_BIT 0x10
  26 #define PDE_PRESENT_BIT 0x01
  27 #define PDE_W_BIT 0x02
  28 #define PDE_PWT_BIT 0x08
  29 #define PDE_PCD_BIT 0x10
  30 #define PDE_ACCESSED_BIT 0x20
  31 #define PDE_DIRTY_BIT 0x40
  32 #define PDE_PS_BIT 0x80
  33
  34 #define MI_KDBG_TMP_PAGE_1 (HYPER_SPACE + 0x400000 - PAGE_SIZE)
  35 #define MI_KDBG_TMP_PAGE_0 (MI_KDBG_TMP_PAGE_1 - PAGE_SIZE)
  36
  37 /* VARIABLES ***************************************************************/
  38
  39 static BOOLEAN KdpPhysAccess = FALSE;
  40
  41 static
  42 ULONG_PTR
  43 KdpPhysMap(ULONG_PTR PhysAddr, LONG Len)
  44 {
  45     MMPTE TempPte;
  46     PMMPTE PointerPte;
  47     ULONG_PTR VirtAddr;
  48
  49     TempPte.u.Long = PDE_PRESENT_BIT | PDE_W_BIT | PDE_PWT_BIT |
  50                      PDE_PCD_BIT | PDE_ACCESSED_BIT | PDE_DIRTY_BIT;
  51
  52     if ((PhysAddr & (PAGE_SIZE - 1)) + Len > PAGE_SIZE)
  53     {
  54         TempPte.u.Hard.PageFrameNumber = (PhysAddr >> PAGE_SHIFT) + 1;
  55         PointerPte = MiAddressToPte((PVOID)MI_KDBG_TMP_PAGE_1);
  56         *PointerPte = TempPte;
  57         VirtAddr = (ULONG_PTR)PointerPte << 10;
  58         KeInvalidateTlbEntry((PVOID)VirtAddr);
  59     }
  60
  61     TempPte.u.Hard.PageFrameNumber = PhysAddr >> PAGE_SHIFT;
  62     PointerPte = MiAddressToPte((PVOID)MI_KDBG_TMP_PAGE_0);
  63     *PointerPte = TempPte;
  64     VirtAddr = (ULONG_PTR)PointerPte << 10;
  65     KeInvalidateTlbEntry((PVOID)VirtAddr);
  66
  67     return VirtAddr + (PhysAddr & (PAGE_SIZE - 1));
  68 }
  69
  70 static
  71 ULONGLONG
  72 KdpPhysRead(ULONG_PTR PhysAddr, LONG Len)
  73 {
  74     ULONG_PTR Addr;
  75     ULONGLONG Result = 0;
  76
  77     Addr = KdpPhysMap(PhysAddr, Len);
  78
  79     switch (Len)
  80     {
  81     case 8:
  82         Result = *((PULONGLONG)Addr);
  83         break;
  84     case 4:
  85         Result = *((PULONG)Addr);
  86         break;
  87     case 2:
  88         Result = *((PUSHORT)Addr);
  89         break;
  90     case 1:
  91         Result = *((PUCHAR)Addr);
  92         break;
  93     }
  94
  95     return Result;
  96 }
  97
  98 static
  99 VOID
 100 KdpPhysWrite(ULONG_PTR PhysAddr, LONG Len, ULONGLONG Value)
 101 {
 102     ULONG_PTR Addr;
 103
 104     Addr = KdpPhysMap(PhysAddr, Len);
 105
 106     switch (Len)
 107     {
 108     case 8:
 109         *((PULONGLONG)Addr) = Value;
 110         break;
 111     case 4:
 112         *((PULONG)Addr) = Value;
 113         break;
 114     case 2:
 115         *((PUSHORT)Addr) = Value;
 116         break;
 117     case 1:
 118         *((PUCHAR)Addr) = Value;
 119         break;
 120     }
 121 }
 122
 123 static
 124 BOOLEAN
 125 KdpTranslateAddress(ULONG_PTR Addr, PULONG_PTR ResultAddr)
 126 {
 127     ULONG_PTR CR3Value = __readcr3();
 128     ULONG_PTR CR4Value = __readcr4();
 129     ULONG_PTR PageDirectory = (CR3Value & ~(PAGE_SIZE-1)) +
 130         ((Addr >> 22) * sizeof(ULONG));
 131     ULONG_PTR PageDirectoryEntry = KdpPhysRead(PageDirectory, sizeof(ULONG));
 132
 133     /* Not present -> fail */
 134     if (!(PageDirectoryEntry & PDE_PRESENT_BIT))
 135     {
 136         return FALSE;
 137     }
 138
 139     /* Big Page? */
 140     if ((PageDirectoryEntry & PDE_PS_BIT) && (CR4Value & CR4_PAGE_SIZE_BIT))
 141     {
 142         *ResultAddr = (PageDirectoryEntry & ~(BIG_PAGE_SIZE-1)) +
 143             (Addr & (BIG_PAGE_SIZE-1));
 144         return TRUE;
 145     }
 146     else
 147     {
 148         ULONG_PTR PageTableAddr =
 149             (PageDirectoryEntry & ~(PAGE_SIZE-1)) +
 150             ((Addr >> PAGE_SHIFT) & PAGE_TABLE_MASK) * sizeof(ULONG);
 151         ULONG_PTR PageTableEntry = KdpPhysRead(PageTableAddr, sizeof(ULONG));
 152         if (PageTableEntry & PDE_PRESENT_BIT)
 153         {
 154             *ResultAddr = (PageTableEntry & ~(PAGE_SIZE-1)) +
 155                 (Addr & (PAGE_SIZE-1));
 156             return TRUE;
 157         }
 158     }
 159
 160     return FALSE;
 161 }
 162
 163 BOOLEAN
 164 NTAPI
 165 KdpSafeReadMemory(ULONG_PTR Addr, LONG Len, PVOID Value)
 166 {
 167     ULONG_PTR ResultPhysAddr;
 168
 169     if (!KdpPhysAccess)
 170     {
 171         memcpy(Value, (PVOID)Addr, Len);
 172         return TRUE;
 173     }
 174
 175     memset(Value, 0, Len);
 176
 177     if (!KdpTranslateAddress(Addr, &ResultPhysAddr))
 178         return FALSE;
 179
 180     switch (Len)
 181     {
 182     case 8:
 183         *((PULONGLONG)Value) = KdpPhysRead(ResultPhysAddr, Len);
 184         break;
 185     case 4:
 186         *((PULONG)Value) = KdpPhysRead(ResultPhysAddr, Len);
 187         break;
 188     case 2:
 189         *((PUSHORT)Value) = KdpPhysRead(ResultPhysAddr, Len);
 190         break;
 191     case 1:
 192         *((PUCHAR)Value) = KdpPhysRead(ResultPhysAddr, Len);
 193         break;
 194     }
 195
 196     return TRUE;
 197 }
 198
 199 BOOLEAN
 200 NTAPI
 201 KdpSafeWriteMemory(ULONG_PTR Addr, LONG Len, ULONGLONG Value)
 202 {
 203     ULONG_PTR ResultPhysAddr;
 204
 205     if (!KdpPhysAccess)
 206     {
 207         memcpy((PVOID)Addr, &Value, Len);
 208         return TRUE;
 209     }
 210
 211     if (!KdpTranslateAddress(Addr, &ResultPhysAddr))
 212         return FALSE;
 213
 214     KdpPhysWrite(ResultPhysAddr, Len, Value);
 215     return TRUE;
 216 }
 217
 218 VOID
 219 NTAPI
 220 KdpEnableSafeMem(VOID)
 221 {
 222     KdpPhysAccess = TRUE;
 223 }
 224
 225 /* EOF */