free, lock, reserve and unreserve pages

kernel/src/PageFrameAllocator.cpp

@@ -31,8 +31,16 @@ void PageFrameAllocator::ReadEFIMemoryMap(EFI_MEMORY_DESCRIPTOR* mMap, size_t mM
 
     InitBitmap(bitmapSize, largestFreeMemSeg);
 
-    //lock pages of bitmap
+    // lock pages of bitmap
+	LockPages(&PageBitmap, PageBitmap.Size / 4096 + 1);
+
     //reserve pages of unsable/reserverd memory
+	for (int i = 0; i < mMapEntries; i++) {
+        EFI_MEMORY_DESCRIPTOR* desc = (EFI_MEMORY_DESCRIPTOR*)((uint64_t)mMap + (i * mMapDescSize));
+        if (desc->type != 7) { // not efiConventionalMemory
+			ReservePages(desc->physAddr, desc->numPages);
+		}
+	}
 }
 
 void PageFrameAllocator::InitBitmap(size_t bitmapSize, void* bufferAddress){
@@ -41,4 +49,81 @@ void PageFrameAllocator::InitBitmap(size_t bitmapSize, void* bufferAddress){
     for (int i = 0; i < bitmapSize; i++){
         *(uint8_t*)(PageBitmap.Buffer + i) = 0; 
     }
+}
+
+void PageFrameAllocator::FreePage(void* address) {
+	uint64_t index = (uint64_t)address / 4096;
+	if (PageBitmap[index] == false) return; // page is already free
+
+	// free page in bitmap
+	PageBitmap.Set(index, false);
+	freeMemory += 4096;
+	usedMemory -= 4096;
+}
+
+void PageFrameAllocator::FreePages(void* address, uint64_t pageCount) {
+	for (int t = 0; t < pageCount; t++) {
+		FreePage((void*)((uint64_t)address + (t * 4096)));
+	}
+}
+
+void PageFrameAllocator::LockPage(void* address) {
+	uint64_t index = (uint64_t)address / 4096;
+	if (PageBitmap[index] == true) return; // page is already locked
+
+	// lock page in bitmap
+	PageBitmap.Set(index, true);
+	freeMemory -= 4096;
+	usedMemory += 4096;
+}
+
+void PageFrameAllocator::LockPages(void* address, uint64_t pageCount) {
+	for (int t = 0; t < pageCount; t++) {
+		LockPage((void*)((uint64_t)address + (t * 4096)));
+	}
+}
+
+void PageFrameAllocator::UnreservePage(void* address) {
+	uint64_t index = (uint64_t)address / 4096;
+	if (PageBitmap[index] == false) return; // page is already free
+
+	// free page in bitmap
+	PageBitmap.Set(index, false);
+	freeMemory += 4096;
+	reservedMemory -= 4096;
+}
+
+void PageFrameAllocator::UnreservePages(void* address, uint64_t pageCount) {
+	for (int t = 0; t < pageCount; t++) {
+		UnreservePage((void*)((uint64_t)address + (t * 4096)));
+	}
+}
+
+void PageFrameAllocator::ReservePage(void* address) {
+	uint64_t index = (uint64_t)address / 4096;
+	if (PageBitmap[index] == true) return; // page is already locked
+
+	// lock page in bitmap
+	PageBitmap.Set(index, true);
+	freeMemory -= 4096;
+	reservedMemory += 4096;
+}
+
+void PageFrameAllocator::ReservePages(void* address, uint64_t pageCount) {
+	for (int t = 0; t < pageCount; t++) {
+		ReservePage((void*)((uint64_t)address + (t * 4096)));
+	}
+}
+
+
+uint64_t PageFrameAllocator::GetFreeRAM() {
+	return freeMemory;
+}
+
+uint64_t PageFrameAllocator::GetUsedRAM() {
+	return usedMemory;
+}
+
+uint64_t PageFrameAllocator::GetReservedRAM() {
+	return reservedMemory;
 }