add vmm_free

kernel/include/vmm.h

@@ -6,4 +6,5 @@
 #define CANONICAL_MASK_USER 0x00007FFFFFFFFFF000
 
 int vmm_alloc(void** vaddr, uint64_t count, uint64_t flags);
+int vmm_free(void* vaddr);
 #endif

kernel/src/vmm.c

@@ -86,4 +86,9 @@ int vmm_alloc(void** vaddr, uint64_t count, uint64_t flags) {
 		}
 	}
 	return SUCCESS;
+}
+
+int vmm_free(void* vaddr) {
+	uint64_t* pml4 = pag_get_pml4();
+	return pag_unmap(pml4, vaddr);
 }