boot/freeldr/freeldr/arcemul/mm.c

   1 /*
   2  * PROJECT:         ReactOS Boot Loader (FreeLDR)
   3  * LICENSE:         GPL - See COPYING in the top level directory
   4  * FILE:            boot/freeldr/freeldr/arcemul/mm.c
   5  * PURPOSE:         Routines for ARC Memory Management
   6  * PROGRAMMERS:     Hervé Poussineau  <hpoussin@reactos.org>
   7  */
   8
   9 /* INCLUDES *******************************************************************/
  10
  11 #include <freeldr.h>
  12 #define NDEBUG
  13 #include <debug.h>
  14
  15 /* FUNCTIONS ******************************************************************/
  16
  17 typedef struct
  18 {
  19     MEMORY_DESCRIPTOR m;
  20     ULONG Index;
  21     BOOLEAN GeneratedDescriptor;
  22 } MEMORY_DESCRIPTOR_INT;
  23 static const MEMORY_DESCRIPTOR_INT MemoryDescriptors[] =
  24 {
  25 #if defined (__i386__) || defined (_M_AMD64)
  26     { { MemoryFirmwarePermanent, 0x00, 1 }, 0, }, // realmode int vectors
  27     { { MemoryFirmwareTemporary, 0x01, 7 }, 1, }, // freeldr stack + cmdline
  28     { { MemoryLoadedProgram, 0x08, 0x70 }, 2, }, // freeldr image (roughly max. 0x64 pages)
  29     { { MemorySpecialMemory, 0x78, 8 }, 3, }, // prot mode stack. BIOSCALLBUFFER
  30     { { MemoryFirmwareTemporary, 0x80, 0x10 }, 4, }, // File system read buffer. FILESYSBUFFER
  31     { { MemoryFirmwareTemporary, 0x90, 0x10 }, 5, }, // Disk read buffer for int 13h. DISKREADBUFFER
  32     { { MemoryFirmwarePermanent, 0xA0, 0x60 }, 6, }, // ROM / Video
  33 #elif __arm__ // This needs to be done per-platform specific way
  34
  35 #endif
  36 };
  37 const MEMORY_DESCRIPTOR*
  38 ArcGetMemoryDescriptor(const MEMORY_DESCRIPTOR* Current)
  39 {
  40     MEMORY_DESCRIPTOR_INT* CurrentDescriptor;
  41     BIOS_MEMORY_MAP BiosMemoryMap[32];
  42     static ULONG BiosMemoryMapEntryCount;
  43     static MEMORY_DESCRIPTOR_INT BiosMemoryDescriptors[32];
  44     static BOOLEAN MemoryMapInitialized = FALSE;
  45     ULONG i, j;
  46
  47     //
  48     // Check if it is the first time we're called
  49     //
  50     if (!MemoryMapInitialized)
  51     {
  52         //
  53         // Get the machine generated memory map
  54         //
  55         RtlZeroMemory(BiosMemoryMap, sizeof(BIOS_MEMORY_MAP) * 32);
  56         BiosMemoryMapEntryCount = MachVtbl.GetMemoryMap(BiosMemoryMap,
  57                                                         sizeof(BiosMemoryMap) /
  58                                                         sizeof(BIOS_MEMORY_MAP));
  59
  60         //
  61         // Copy the entries to our structure
  62         //
  63         for (i = 0, j = 0; i < BiosMemoryMapEntryCount; i++)
  64         {
  65             //
  66             // Is it suitable memory?
  67             //
  68             if (BiosMemoryMap[i].Type != BiosMemoryUsable)
  69             {
  70                 //
  71                 // No. Process next descriptor
  72                 //
  73                 continue;
  74             }
  75
  76             //
  77             // Copy this memory descriptor
  78             //
  79             BiosMemoryDescriptors[j].m.MemoryType = MemoryFree;
  80             BiosMemoryDescriptors[j].m.BasePage = (ULONG)(BiosMemoryMap[i].BaseAddress / MM_PAGE_SIZE);
  81             BiosMemoryDescriptors[j].m.PageCount = (ULONG)(BiosMemoryMap[i].Length / MM_PAGE_SIZE);
  82             BiosMemoryDescriptors[j].Index = j;
  83             BiosMemoryDescriptors[j].GeneratedDescriptor = TRUE;
  84             j++;
  85         }
  86
  87         //
  88         // Remember how much descriptors we found
  89         //
  90         BiosMemoryMapEntryCount = j;
  91
  92         //
  93         // Mark memory map as already retrieved and initialized
  94         //
  95         MemoryMapInitialized = TRUE;
  96     }
  97
  98     CurrentDescriptor = CONTAINING_RECORD(Current, MEMORY_DESCRIPTOR_INT, m);
  99
 100     if (Current == NULL)
 101     {
 102         //
 103         // First descriptor requested
 104         //
 105         if (BiosMemoryMapEntryCount > 0)
 106         {
 107             //
 108             // Return first generated memory descriptor
 109             //
 110             return &BiosMemoryDescriptors[0].m;
 111         }
 112         else if (sizeof(MemoryDescriptors) > 0)
 113         {
 114             //
 115             // Return first fixed memory descriptor
 116             //
 117             return &MemoryDescriptors[0].m;
 118         }
 119         else
 120         {
 121             //
 122             // Strange case, we have no memory descriptor
 123             //
 124             return NULL;
 125         }
 126     }
 127     else if (CurrentDescriptor->GeneratedDescriptor)
 128     {
 129         //
 130         // Current entry is a generated descriptor
 131         //
 132         if (CurrentDescriptor->Index + 1 < BiosMemoryMapEntryCount)
 133         {
 134             //
 135             // Return next generated descriptor
 136             //
 137             return &BiosMemoryDescriptors[CurrentDescriptor->Index + 1].m;
 138         }
 139         else if (sizeof(MemoryDescriptors) > 0)
 140         {
 141             //
 142             // Return first fixed memory descriptor
 143             //
 144             return &MemoryDescriptors[0].m;
 145         }
 146         else
 147         {
 148             //
 149             // No fixed memory descriptor; end of memory map
 150             //
 151             return NULL;
 152         }
 153     }
 154     else
 155     {
 156         //
 157         // Current entry is a fixed descriptor
 158         //
 159         if (CurrentDescriptor->Index + 1 < sizeof(MemoryDescriptors) / sizeof(MemoryDescriptors[0]))
 160         {
 161             //
 162             // Return next fixed descriptor
 163             //
 164             return &MemoryDescriptors[CurrentDescriptor->Index + 1].m;
 165         }
 166         else
 167         {
 168             //
 169             // No more fixed memory descriptor; end of memory map
 170             //
 171             return NULL;
 172         }
 173     }
 174 }