public static PageAttributes GetPageAttributes (void* page, uint granularity,
PageAllocator.Errors* ret_err)
{
return Pager.GetPageAttributes (page, granularity, ret_err);
}
public static PageAttributes GetPageAttributes (void* page, uint granularity,
PageAllocator.Errors* ret_err)
{
uint pde = 0, pte = 0;
uint* table = null;
if (granularity < 0 || granularity > 1) {
*ret_err = PageAllocator.Errors.UnsupportedGranularity;
return PageAttributes.None;
}
Diagnostics.Assert(ADC.Pager.GetPointerGranularity(page) == granularity,
"X86.Pager.GetPageAttributes(): bad page pointer alignment!");
PagePtrToTables(page, &pde, &pte);
table = PageDirectory;
if (granularity == 0)
table = (uint*)(table[pde] & (uint)PageAttr.FrameMask);
*ret_err = PageAllocator.Errors.Success;
return GetAbstractPMA((PageAttr)(table[pde] &
(uint)PageAttr.AttributeMask));
}
public static PageAllocator.Errors Setup(uint totalMem, byte* pagemap, uint pagemapLen, PageAllocator.Errors* error)
{
if (pagemap == null ||
pagemapLen < ComputeControlReq(totalMem)) {
*error = PageAllocator.Errors.UnusablePageControlBuffer;
return *error;
}
uint totalBytes = totalMem * 1024; // more intuitive to think in bytes than in kibibytes
PageDirectory = (uint*)pagemap;
PageTables = (uint*)(((byte*)PageDirectory) + 4096);
uint addr = 0;
uint* table = (uint*)PageTables;
// Page directory needs to span all 4 GBs
// FIXME: What about PAE support might different implementation
// uint totalPages = UInt32.MaxValue / 4096; // Each page spans of memory 4MB
uint totalTables = 1024; // 1024 * 4MB = 4GB
MemoryUtil.MemSet32(0, (uint)PageDirectory, 1024);
for (int x = 0; x < totalTables; ++x) {
bool needsDirectoryPresent = false;
for (int i = 0; i < 1024; ++i) {
uint val = (addr & (uint)PageAttr.FrameMask) |
(uint)(PageAttr.ReadWrite);
if (addr <= totalBytes) {
val |= (uint)PageAttr.Present;
needsDirectoryPresent = true;
}
table[i] = val;
addr += 4096;
}
// top-level page directory (level-1)
uint pageAddress = (uint)table & (uint)PageAttr.FrameMask;
// Make direcory read/write enabled
pageAddress |= (uint)PageAttr.ReadWrite;
if (needsDirectoryPresent) {
// Make directory present if its point to a physical memory already
pageAddress |= (uint)PageAttr.Present;
}
PageDirectory[x] = pageAddress;
table += 1024; // 1024 x sizeof(int) = 4k
}
DMA.Setup((byte*)((uint)pagemap) + pagemapLen);
*error = PageAllocator.Errors.Success;
return *error;
}
public static PageAllocator.Errors Enable(PageAllocator.Errors* error)
{
if (PageDirectory == null) {
*error = PageAllocator.Errors.UnusablePageControlBuffer;
return *error;
}
SetDirectory((uint)PageDirectory);
*error = PageAllocator.Errors.Success;
return *error;
}
public static uint GetGranularitySize(uint granularity, PageAllocator.Errors* ret_err)
{
if (granularity < 0 || granularity > 1) {
*ret_err = PageAllocator.Errors.UnsupportedGranularity;
return 0;
}
*ret_err = PageAllocator.Errors.Success;
switch (granularity) {
case 0:
return 4096;
case 1:
return 131072;
default:
*ret_err = PageAllocator.Errors.UnsupportedGranularity;
return 0xFFFFFFFF;
}
}
