page.c

ReactOS是一些高手根据Windows XP的内核编写出的类XP。内核实现机理和API函数调用几乎相同。甚至可以兼容XP的程序。喜欢研究系统内核的人可以看一看。

   }
   else
   {
      MmReleasePageMemoryConsumer(MC_NPPOOL, Pfn);
   }
   if (Process != NULL && Process != CurrentProcess)
   {
      KeDetachProcess();
   }
}

static PULONGLONG
MmGetPageTableForProcessForPAE(PEPROCESS Process, PVOID Address, BOOLEAN Create)
{
   NTSTATUS Status;
   PFN_TYPE Pfn;
   ULONGLONG Entry;
   ULONGLONG ZeroEntry = 0LL;
   PULONGLONG Pt;
   PULONGLONG PageDir;
   PULONGLONG PageDirTable;

   DPRINT("MmGetPageTableForProcessForPAE(%x %x %d)\n",
          Process, Address, Create);
   if (Address >= (PVOID)PAGETABLE_MAP && Address < (PVOID)((ULONG_PTR)PAGETABLE_MAP + 0x800000))
   {
      KEBUGCHECK(0);
   }
   if (Address < MmSystemRangeStart && Process && Process != PsGetCurrentProcess())
   {
      PageDirTable = MmCreateHyperspaceMapping(PAE_PTE_TO_PFN(Process->Pcb.DirectoryTableBase.QuadPart));
      if (PageDirTable == NULL)
      {
         KEBUGCHECK(0);
      }
      PageDir = MmCreateHyperspaceMapping(PAE_PTE_TO_PFN(PageDirTable[PAE_ADDR_TO_PDTE_OFFSET(Address)]));
      MmDeleteHyperspaceMapping(PageDirTable);
      if (PageDir == NULL)
      {
         KEBUGCHECK(0);
      }
      PageDir += PAE_ADDR_TO_PDE_PAGE_OFFSET(Address);
      Entry = ExfInterlockedCompareExchange64UL(PageDir, &ZeroEntry, &ZeroEntry);
      if (Entry == 0LL)
      {
         if (Create == FALSE)
	 {
	    MmDeleteHyperspaceMapping(PageDir);
	    return NULL;
	 }
         Status = MmRequestPageMemoryConsumer(MC_NPPOOL, FALSE, &Pfn);
	 if (!NT_SUCCESS(Status))
	 {
	    KEBUGCHECK(0);
	 }
         Entry = PFN_TO_PTE(Pfn) | PA_PRESENT | PA_READWRITE | PA_USER;
	 Entry = ExfInterlockedCompareExchange64UL(PageDir, &Entry, &ZeroEntry);
	 if (Entry != 0LL)
	 {
	    MmReleasePageMemoryConsumer(MC_NPPOOL, Pfn);
	    Pfn = PAE_PTE_TO_PFN(Entry);
	 }
      }
      else
      {
         Pfn = PAE_PTE_TO_PFN(Entry);
      }
      MmDeleteHyperspaceMapping(PageDir);
      Pt = MmCreateHyperspaceMapping(Pfn);
      if (Pt == NULL)
      {
         KEBUGCHECK(0);
      }
      return Pt + PAE_ADDR_TO_PTE_OFFSET(Address);
   }
   PageDir = PAE_ADDR_TO_PDE(Address);
   if (0LL == ExfInterlockedCompareExchange64UL(PageDir, &ZeroEntry, &ZeroEntry))
   {
      if (Address >= MmSystemRangeStart)
      {
	 if (MmGlobalKernelPageDirectoryForPAE[PAE_ADDR_TO_PDE_OFFSET(Address)] == 0LL)
	 {
	    if (Create == FALSE)
	    {
               return NULL;
	    }
            Status = MmRequestPageMemoryConsumer(MC_NPPOOL, FALSE, &Pfn);
	    if (!NT_SUCCESS(Status))
	    {
	       KEBUGCHECK(0);
	    }
	    Entry = PAE_PFN_TO_PTE(Pfn) | PA_PRESENT | PA_READWRITE;
            if (Ke386GlobalPagesEnabled)
	    {
	       Entry |= PA_GLOBAL;
	    }
	    if (0LL != ExfInterlockedCompareExchange64UL(&MmGlobalKernelPageDirectoryForPAE[PAE_ADDR_TO_PDE_OFFSET(Address)], &Entry, &ZeroEntry))
	    {
	       MmReleasePageMemoryConsumer(MC_NPPOOL, Pfn);
	    }
	 }
	 (void)ExfInterlockedCompareExchange64UL(PageDir, &MmGlobalKernelPageDirectoryForPAE[PAE_ADDR_TO_PDE_OFFSET(Address)], &ZeroEntry);
      }
      else
      {
	 if (Create == FALSE)
	 {
            return NULL;
	 }
         Status = MmRequestPageMemoryConsumer(MC_NPPOOL, FALSE, &Pfn);
	 if (!NT_SUCCESS(Status))
	 {
	    KEBUGCHECK(0);
	 }
	 Entry = PFN_TO_PTE(Pfn) | PA_PRESENT | PA_READWRITE | PA_USER;
         Entry = ExfInterlockedCompareExchange64UL(PageDir, &Entry, &ZeroEntry);
	 if (Entry != 0LL)
	 {
	    MmReleasePageMemoryConsumer(MC_NPPOOL, Pfn);
	 }
      }
   }
   return (PULONGLONG)PAE_ADDR_TO_PTE(Address);
}

static PULONG
MmGetPageTableForProcess(PEPROCESS Process, PVOID Address, BOOLEAN Create)
{
   ULONG PdeOffset = ADDR_TO_PDE_OFFSET(Address);
   NTSTATUS Status;
   PFN_TYPE Pfn;
   ULONG Entry;
   PULONG Pt, PageDir;

   if (Address < MmSystemRangeStart && Process && Process != PsGetCurrentProcess())
   {
      PageDir = MmCreateHyperspaceMapping(PTE_TO_PFN(Process->Pcb.DirectoryTableBase.LowPart));
      if (PageDir == NULL)
      {
         KEBUGCHECK(0);
      }
      if (0 == InterlockedCompareExchangeUL(&PageDir[PdeOffset], 0, 0))
      {
         if (Create == FALSE)
	 {
	    MmDeleteHyperspaceMapping(PageDir);
	    return NULL;
	 }
         Status = MmRequestPageMemoryConsumer(MC_NPPOOL, FALSE, &Pfn);
	 if (!NT_SUCCESS(Status) || Pfn == 0)
	 {
	    KEBUGCHECK(0);
	 }
         Entry = InterlockedCompareExchangeUL(&PageDir[PdeOffset], PFN_TO_PTE(Pfn) | PA_PRESENT | PA_READWRITE | PA_USER, 0);
	 if (Entry != 0)
	 {
	    MmReleasePageMemoryConsumer(MC_NPPOOL, Pfn);
	    Pfn = PTE_TO_PFN(Entry);
	 }
      }
      else
      {
         Pfn = PTE_TO_PFN(PageDir[PdeOffset]);
      }
      MmDeleteHyperspaceMapping(PageDir);
      Pt = MmCreateHyperspaceMapping(Pfn);
      if (Pt == NULL)
      {
         KEBUGCHECK(0);
      }
      return Pt + ADDR_TO_PTE_OFFSET(Address);
   }
   PageDir = ADDR_TO_PDE(Address);
   if (0 == InterlockedCompareExchangeUL(PageDir, 0, 0))
   {
      if (Address >= MmSystemRangeStart)
      {
         if (0 == InterlockedCompareExchangeUL(&MmGlobalKernelPageDirectory[PdeOffset], 0, 0))
	 {
	    if (Create == FALSE)
	    {
               return NULL;
	    }
            Status = MmRequestPageMemoryConsumer(MC_NPPOOL, FALSE, &Pfn);
	    if (!NT_SUCCESS(Status) || Pfn == 0)
	    {
	       KEBUGCHECK(0);
	    }
	    Entry = PFN_TO_PTE(Pfn) | PA_PRESENT | PA_READWRITE;
            if (Ke386GlobalPagesEnabled)
	    {
	       Entry |= PA_GLOBAL;
	    }
	    if(0 != InterlockedCompareExchangeUL(&MmGlobalKernelPageDirectory[PdeOffset], Entry, 0))
	    {
	       MmReleasePageMemoryConsumer(MC_NPPOOL, Pfn);
	    }
	 }
         (void)InterlockedExchangeUL(PageDir, MmGlobalKernelPageDirectory[PdeOffset]);
      }
      else
      {
	 if (Create == FALSE)
	 {
            return NULL;
	 }
         Status = MmRequestPageMemoryConsumer(MC_NPPOOL, FALSE, &Pfn);
	 if (!NT_SUCCESS(Status) || Pfn == 0)
	 {
	    KEBUGCHECK(0);
	 }
         Entry = InterlockedCompareExchangeUL(PageDir, PFN_TO_PTE(Pfn) | PA_PRESENT | PA_READWRITE | PA_USER, 0);
	 if (Entry != 0)
	 {
	    MmReleasePageMemoryConsumer(MC_NPPOOL, Pfn);
	 }
      }
   }
   return (PULONG)ADDR_TO_PTE(Address);
}

BOOLEAN MmUnmapPageTable(PULONG Pt)
{
   if (Ke386Pae)
   {
      if ((PULONGLONG)Pt >= (PULONGLONG)PAGETABLE_MAP && (PULONGLONG)Pt < (PULONGLONG)PAGETABLE_MAP + 4*512*512)
      {
         return TRUE;
      }
   }
   else
   {
      if (Pt >= (PULONG)PAGETABLE_MAP && Pt < (PULONG)PAGETABLE_MAP + 1024*1024)
      {
         return TRUE;
      }
   }
   if (Pt)
   {
      MmDeleteHyperspaceMapping((PVOID)PAGE_ROUND_DOWN(Pt));
   }
   return FALSE;
}

static ULONGLONG MmGetPageEntryForProcessForPAE(PEPROCESS Process, PVOID Address)
{
   ULONGLONG Pte;
   PULONGLONG Pt;

   Pt = MmGetPageTableForProcessForPAE(Process, Address, FALSE);
   if (Pt)
   {
      Pte = *Pt;
      MmUnmapPageTable((PULONG)Pt);
      return Pte;
   }
   return 0;
}

static ULONG MmGetPageEntryForProcess(PEPROCESS Process, PVOID Address)
{
   ULONG Pte;
   PULONG Pt;

   Pt = MmGetPageTableForProcess(Process, Address, FALSE);
   if (Pt)
   {
      Pte = *Pt;
      MmUnmapPageTable(Pt);
      return Pte;
   }
   return 0;
}

PFN_TYPE
NTAPI
MmGetPfnForProcess(PEPROCESS Process,
                   PVOID Address)
{

   if (Ke386Pae)
   {
      ULONGLONG Entry;
      Entry = MmGetPageEntryForProcessForPAE(Process, Address);
      if (!(Entry & PA_PRESENT))
      {
         return 0;
      }
      return(PAE_PTE_TO_PFN(Entry));
   }
   else
   {
      ULONG Entry;
      Entry = MmGetPageEntryForProcess(Process, Address);
      if (!(Entry & PA_PRESENT))
      {
         return 0;
      }
      return(PTE_TO_PFN(Entry));
   }
}

VOID
NTAPI
MmDisableVirtualMapping(PEPROCESS Process, PVOID Address, BOOLEAN* WasDirty, PPFN_TYPE Page)
/*
 * FUNCTION: Delete a virtual mapping
 */
{
   BOOLEAN WasValid;
   if (Ke386Pae)
   {
      ULONGLONG Pte;
      ULONGLONG tmpPte;
      PULONGLONG Pt;

      Pt = MmGetPageTableForProcessForPAE(Process, Address, FALSE);
      if (Pt == NULL)
      {
         KEBUGCHECK(0);
      }
      /*
       * Atomically disable the present bit and get the old value.
       */
      do
      {
        Pte = *Pt;
	tmpPte = Pte & ~PA_PRESENT;
      } while (Pte != ExfInterlockedCompareExchange64UL(Pt, &tmpPte, &Pte));

      MiFlushTlb((PULONG)Pt, Address);
      WasValid = PAE_PAGE_MASK(Pte) != 0LL ? TRUE : FALSE;
      if (!WasValid)
      {
         KEBUGCHECK(0);
      }

      /*
       * Return some information to the caller
       */
      if (WasDirty != NULL)
      {
	  *WasDirty = Pte & PA_DIRTY ? TRUE : FALSE;
      }
      if (Page != NULL)
      {
         *Page = PAE_PTE_TO_PFN(Pte);
      }
   }
   else
   {
      ULONG Pte;
      PULONG Pt;

      Pt = MmGetPageTableForProcess(Process, Address, FALSE);
      if (Pt == NULL)
      {
         KEBUGCHECK(0);
      }
      /*
       * Atomically disable the present bit and get the old value.
       */
      do
      {
        Pte = *Pt;
      } while (Pte != InterlockedCompareExchangeUL(Pt, Pte & ~PA_PRESENT, Pte));

      MiFlushTlb(Pt, Address);
      WasValid = (PAGE_MASK(Pte) != 0);
      if (!WasValid)
      {
         KEBUGCHECK(0);
      }

      /*
       * Return some information to the caller
       */
      if (WasDirty != NULL)
      {
         *WasDirty = Pte & PA_DIRTY;
      }
      if (Page != NULL)
      {
         *Page = PTE_TO_PFN(Pte);
      }
   }
}

VOID
NTAPI
MmRawDeleteVirtualMapping(PVOID Address)
{
   if (Ke386Pae)
   {
      PULONGLONG Pt;
      ULONGLONG ZeroPte = 0LL;
      Pt = MmGetPageTableForProcessForPAE(NULL, Address, FALSE);
      if (Pt)
      {
         /*
          * Set the entry to zero
          */
	 (void)ExfpInterlockedExchange64UL(Pt, &ZeroPte);
         MiFlushTlb((PULONG)Pt, Address);
      }
   }
   else
   {
      PULONG Pt;

      Pt = MmGetPageTableForProcess(NULL, Address, FALSE);
      if (Pt && *Pt)
      {
         /*
          * Set the entry to zero
          */
         (void)InterlockedExchangeUL(Pt, 0);
         MiFlushTlb(Pt, Address);
      }
   }
}

VOID
NTAPI
MmDeleteVirtualMapping(PEPROCESS Process, PVOID Address, BOOLEAN FreePage,
                       BOOLEAN* WasDirty, PPFN_TYPE Page)
/*
 * FUNCTION: Delete a virtual mapping
 */
{
   BOOLEAN WasValid = FALSE;
   PFN_TYPE Pfn;

   DPRINT("MmDeleteVirtualMapping(%x, %x, %d, %x, %x)\n",
          Process, Address, FreePage, WasDirty, Page);
   if (Ke386Pae)
   {
      ULONGLONG Pte;
      PULONGLONG Pt;

      Pt = MmGetPageTableForProcessForPAE(Process, Address, FALSE);
      if (Pt == NULL)
      {
         if (WasDirty != NULL)
         {
            *WasDirty = FALSE;
         }
         if (Page != NULL)
         {
            *Page = 0;
         }
         return;
      }

      /*
       * Atomically set the entry to zero and get the old value.
       */
      Pte = 0LL;
      Pte = ExfpInterlockedExchange64UL(Pt, &Pte);

      MiFlushTlb((PULONG)Pt, Address);

      WasValid = PAE_PAGE_MASK(Pte) != 0 ? TRUE : FALSE;
      if (WasValid)
      {
         Pfn = PAE_PTE_TO_PFN(Pte);
         MmMarkPageUnmapped(Pfn);
      }
      else
      {
         Pfn = 0;
      }

      if (FreePage && WasValid)
      {
         MmReleasePageMemoryConsumer(MC_NPPOOL, Pfn);
      }

      /*
       * Return some information to the caller
       */
      if (WasDirty != NULL)
      {
         *WasDirty = Pte & PA_DIRTY ? TRUE : FALSE;
      }
      if (Page != NULL)
      {
         *Page = Pfn;
      }
   }
   else