/// <summary>
/// Reserves a range of memory pages so that they cannot be allocated using
/// <see cref="M:Alloc()" /> or <see cref="M:RangeAlloc(uint count)" />.
/// </summary>
/// <param name="pageStart">
/// A pointer which is aligned along the platform's native page boundaries.
/// </param>
/// <param name="pages">
/// The amount of pages to reserve.
/// </param>
public static bool ReservePageRange(void *firstPage, uint pages, string name)
{
ReservedPages *reservePages = GetReservedPage();
reservePages->Address = (uint)firstPage;
reservePages->Size = pages;
return(true);
}
private static void DumpReservedStack(ReservedPages *pageStack, uint stackPtr, int count)
{
for (int i = (int)stackPtr - 1; i >= 0 && i >= stackPtr - count; i--)
{
ADC.TextMode.Write(i);
ADC.TextMode.Write(": Address: ");
ADC.TextMode.Write((int)pageStack->Address);
ADC.TextMode.Write(", Size: ");
ADC.TextMode.Write((int)pageStack->Size);
pageStack++;
ADC.TextMode.WriteLine();
}
}
/// <summary>
/// Returns true if the given page is reserved (that is, not available for allocation).
/// </summary>
public static bool IsPageReserved(void *page)
{
uint sp = 0;
ReservedPages *ptr = rpStack;
uint pageAddr = (uint)page;
while (sp < rpStackPointer)
{
if (pageAddr >= ptr[sp].Address && pageAddr < (ptr[sp].Address + (ptr[sp].Size * Pager.AtomicPageSize)))
{
return(true);
}
sp++;
}
return(false);
}
/// <summary>
/// Reserves a memory page so that it cannot be allocated using
/// <see cref="M:Alloc()" /> or <see cref="M:RangeAlloc(uint count)" />.
/// </summary>
/// <param name="page">
/// A pointer which is aligned along the platform's native page boundaries.
/// </param>
public static bool ReservePage(void *page)
{
if (page == null)
{
return(false);
}
// we should be doing this.. but it's so slow..
if (IsPageReserved(page)) // ugh...
{
return(true);
}
//if (!IsPageFree(page, &fsp))
// return false;
ReservedPages *pages = GetReservedPage();
pages->Address = (uint)page;
pages->Size = 1;
return(true);
}
/// <summary>
/// Initializes page management and paging. Using <see cref="Alloc" />
/// and related management functions before calling this function results
/// in a kernel panic. After this function is called, the
/// <see cref="ReservePage"/> and <see cref="ReservePageRange" />
/// functions can be used to reserve memory that should not be allocated.
/// You should ensure that no memory allocations have happened between
/// calling this function and reserving memory.
/// </summary>
public static void Setup (byte* kernelOffset, uint _kernelSize, uint totalKbMem)
{
PagingMemoryRequirements* pagingMemory = stackalloc PagingMemoryRequirements[1];
// The total memory in bytes
totalMem = totalKbMem * 1024;
// Total pages
totalPages = totalMem / Pager.AtomicPageSize;
// First page of the kernel
kernelStartPage = (byte*)PtrToPage (kernelOffset);
// Kernel size in pages
kernelSize = (_kernelSize / Pager.AtomicPageSize) + 1;
// Allocate the free page stack immediately after end of the kernel
fpStack = (uint*)(kernelStartPage + (kernelSize * Pager.AtomicPageSize));
// Initalize the stack pointer
fpStackPointer = 0;
// Free page stack size in pages
fpStackSize = (totalPages * (uint)sizeof (uint*) / Pager.AtomicPageSize) + 1;
// Allocate the reserved page stack immediately after free page stack
rpStack = (ReservedPages*)((uint)fpStack + (fpStackSize * Pager.AtomicPageSize));
// Initalize the reserve stack pointer
rpStackPointer = 0;
// Reserve stack size in pages
rpStackSize = 1; // fixed - should be enough
// Allocate paging information
pagingData = (byte*)(rpStack + (rpStackSize * Pager.AtomicPageSize));
pagingMemory->Start = (void*)pagingData;
// Reserve 4 mega bytes of memory for Virtual memory manager
// FIXME:
pagingDataSize = (4 * 1024 * 1024) / 4096;
// Reserve the memory ranges we're using.
ReservePageRange (kernelStartPage, kernelSize, "kernel");
ReservePageRange (fpStack, fpStackSize, "fpstack");
ReservePageRange (rpStack, rpStackSize, "rpstack");
ReservePageRange (pagingData, pagingDataSize, "paging");
// Reserve memory below 0x100000 (1MB) for the BIOS/video memory
ReservePageRange ((void*)0, (0x100000 / ADC.Pager.AtomicPageSize), "Reserve memory below 0x100000 (1MB) for the BIOS/video memory");
// FIXME: the value we get back from Pager.Setup is not the same value that
// we 'return' from inside the method itself!!!!
Errors error = Errors.Unknown;
Pager.Setup (totalKbMem, pagingData, pagingDataSize, &error);
if (error != Errors.Success) {
PrintError (error);
return;
}
// NOTE: 0x0000 page is reserved
currentPage = 1;
error = Errors.Unknown;
Pager.Enable (&error);
if (error != Errors.Success)
PrintError (error);
}
/// <summary>
/// Initializes page management and paging. Using <see cref="Alloc" />
/// and related management functions before calling this function results
/// in a kernel panic. After this function is called, the
/// <see cref="ReservePage"/> and <see cref="ReservePageRange" />
/// functions can be used to reserve memory that should not be allocated.
/// You should ensure that no memory allocations have happened between
/// calling this function and reserving memory.
/// </summary>
public static void Setup(byte *kernelOffset, uint _kernelSize, uint totalKbMem)
{
PagingMemoryRequirements *pagingMemory = stackalloc PagingMemoryRequirements[1];
// The total memory in bytes
totalMem = totalKbMem * 1024;
// Total pages
totalPages = totalMem / Pager.AtomicPageSize;
// First page of the kernel
kernelStartPage = (byte *)PtrToPage(kernelOffset);
// Kernel size in pages
kernelSize = (_kernelSize / Pager.AtomicPageSize) + 1;
// Allocate the free page stack immediately after end of the kernel
fpStack = (uint *)(kernelStartPage + (kernelSize * Pager.AtomicPageSize));
// Initalize the stack pointer
fpStackPointer = 0;
// Free page stack size in pages
fpStackSize = (totalPages * (uint)sizeof(uint *) / Pager.AtomicPageSize) + 1;
// Allocate the reserved page stack immediately after free page stack
rpStack = (ReservedPages *)((uint)fpStack + (fpStackSize * Pager.AtomicPageSize));
// Initalize the reserve stack pointer
rpStackPointer = 0;
// Reserve stack size in pages
rpStackSize = 1; // fixed - should be enough
// Allocate paging information
pagingData = (byte *)(rpStack + (rpStackSize * Pager.AtomicPageSize));
pagingMemory->Start = (void *)pagingData;
// Reserve 4 mega bytes of memory for Virtual memory manager
// FIXME:
pagingDataSize = (4 * 1024 * 1024) / 4096;
// Reserve the memory ranges we're using.
ReservePageRange(kernelStartPage, kernelSize, "kernel");
ReservePageRange(fpStack, fpStackSize, "fpstack");
ReservePageRange(rpStack, rpStackSize, "rpstack");
ReservePageRange(pagingData, pagingDataSize, "paging");
// Reserve memory below 0x100000 (1MB) for the BIOS/video memory
ReservePageRange((void *)0, (0x100000 / ADC.Pager.AtomicPageSize), "Reserve memory below 0x100000 (1MB) for the BIOS/video memory");
// FIXME: the value we get back from Pager.Setup is not the same value that
// we 'return' from inside the method itself!!!!
Errors error = Errors.Unknown;
Pager.Setup(totalKbMem, pagingData, pagingDataSize, &error);
if (error != Errors.Success)
{
PrintError(error);
return;
}
// NOTE: 0x0000 page is reserved
currentPage = 1;
error = Errors.Unknown;
Pager.Enable(&error);
if (error != Errors.Success)
{
PrintError(error);
}
}
