finish the vmm

src/arch/x86_64/include/arch/mmu.h

@@ -3,6 +3,7 @@
 
 #include <stdint.h>
 #include <stddef.h>
+#include <stdbool.h>
 
 #define PAGE_SIZE 4096
 
@@ -11,10 +12,13 @@
 #define ARCH_MMU_MAP_USER         (uint64_t)(1 << 2)
 #define ARCH_MMU_MAP_NOEXEC       (uint64_t)(1 << 63)
 #define ARCH_MMU_MAP_PAGESIZE     (uint64_t)(1 << 7)
+#define ARCH_MMU_MAP_ACCESSED	  (uint64_t)(1 << 5)
 
 typedef uint64_t* arch_mmu_tableptr;
 
 int arch_mmu_map(arch_mmu_tableptr, void*, void*, size_t);
+bool arch_mmu_isaccessed(arch_mmu_tableptr, void*);
+void* arch_mmu_getphysicaladdr(arch_mmu_tableptr, void*);
 void arch_mmu_unmap(arch_mmu_tableptr, void*);
 void arch_mmu_init();
 

src/arch/x86_64/mmu.c

@@ -31,6 +31,22 @@ static void invalidate(void* addr){
 	asm("invlpg (%%rax)" : : "a"(addr));
 }
 
+
+static uint64_t* next(uint64_t* table, size_t offset){
+	
+	table = (uint64_t)table & ~(0xFFF);
+	
+	if(table < limine_hhdm_offset){
+		table = (uint64_t)table & ~(1 << 63); // remove NX
+		table = (uint64_t)table + (uint64_t)limine_hhdm_offset;
+	}
+	
+	return table[offset];
+
+}
+
+// FIXME make the accessed addresses be in the limine hhdm
+
 static bool setpage(arch_mmu_tableptr context, void* vaddr, uint64_t entry){
 	uint64_t addr = (uint64_t)vaddr;
 	size_t pdpt = (addr >> 39) & 0b111111111;
@@ -81,6 +97,40 @@ static bool setpage(arch_mmu_tableptr context, void* vaddr, uint64_t entry){
 
 
 
+static uint64_t getmapping(arch_mmu_tableptr context, void* vaddr){
+	uint64_t addr = (uint64_t)vaddr;
+        size_t pdpt = (addr >> 39) & 0b111111111;
+        size_t pd   = (addr >> 30) & 0b111111111;
+        size_t pt   = (addr >> 21) & 0b111111111;
+        size_t page = (addr >> 12) & 0b111111111;
+
+	if(!context[pdpt]) return 0;
+	
+	uint64_t* table = next(context, pd);
+	
+	if(!table) return 0;
+
+	table = next(table, pt);
+
+	if(!table) return 0;
+
+	table = next(table, page);
+
+	return table;
+
+}
+
+void* arch_mmu_getphysicaladdr(arch_mmu_tableptr context, void* addr){
+	uint64_t paddr = getmapping(context, addr);
+	paddr &= ~(0xFFF);
+	paddr &= ~ARCH_MMU_MAP_NOEXEC;
+	return paddr;
+}
+
+bool arch_mmu_isaccessed(arch_mmu_tableptr context, void* addr){
+	return (getmapping(context, addr) & ARCH_MMU_MAP_ACCESSED) != 0;
+}
+
 int arch_mmu_map(arch_mmu_tableptr context, void* paddr, void* vaddr, size_t flags){
 	uint64_t entry;
 	changeentry(&entry, paddr, flags);