[lcrash] ADD: Virtual memory manager

lcrash/mm/virt.c

@@ -6,6 +6,23 @@
 u64 (*VmemOriginalPML4)[512] = 0;
 u64 (*VmemPML4)[512] = 0;
 
+void VmemMapMemory(void* Phys, void* Virt, u64 Size) {
+	u64 PhysStart = (u64)Phys;
+	u64 VirtStart = (u64)Virt;
+
+	if ((PhysStart | VirtStart | Size) & 0xfff) Panic("VmemMapMemory: Addresses not page aligned");
+
+	for (u64 Offset4 = VirtStart; Offset4 < VirtStart + Size; Offset4 += 0x8000000000) {
+		for (u64 Offset3 = Offset4; Offset3 < VirtStart + Size && Offset3 < Offset4 + 0x8000000000; Offset3 += 0x40000000) {
+			for (u64 Offset2 = Offset3; Offset2 < VirtStart + Size && Offset2 < Offset3 + 0x40000000; Offset2 += 0x200000) {
+				for (u64 Offset1 = Offset2; Offset2 < VirtStart + Size && Offset1 < Offset2 + 0x200000; Offset1 += 0x1000) {
+					
+				}
+			}
+		}
+	}
+}
+
 void VmemInitialize() {
 	// Copy control registers
 	u64 CR3;

lcrash/mm/virt.h

@@ -2,4 +2,10 @@
 
 #include <lcrash/types.h>
 
-void VmemInitialize(); 
+void VmemInitialize();
+
+/**
+ * Map a range of physical addresses to a range of virtual addresses
+ * Must be page-aligned
+ */
+void VmemMapMemory(void* PhysStart, void* VirtStart, u64 Size);

lcrash/pci/pci.c

@@ -1,5 +1,6 @@
 #include <lcrash/pci/pci.h>
 
+#include <lcrash/mm/virt.h>
 #include <lcrash/acpi/acpi.h>
 #include <lcrash/debug/debug.h>
 #include <lcrash/driver/sysbus.h>
@@ -35,6 +36,12 @@ void PciInitialize() {
 	// Take our pcie bridges
 	s32 Length = (BridgeTable->Header.Length - 44) / 16;
 	for (int i = 0; i < Length; i++) {
+		// Identity map our busses because linux doesn't do it for us
+		VmemMapMemory(
+			BridgeTable->Bridges[i].Address, BridgeTable->Bridges[i].Address,
+			(BridgeTable->Bridges[i].EndBus - BridgeTable->Bridges[i].StartBus) * 0x100000
+		);
+
 		for (int Bus = BridgeTable->Bridges[i].StartBus; Bus < BridgeTable->Bridges[i].EndBus; Bus++) {
 			PciBusses[Bus] = BridgeTable->Bridges[i].Address + (Bus - BridgeTable->Bridges[i].StartBus) * 0x100000;
 		}