x86_64: pmap: implement pmap_destroy()

arch/x86_64/pmap.c

@@ -100,7 +100,7 @@ static void delete_ptab(phys_addr_t pt)
 		return;
 	}
 
-	pt &= ~VM_PAGE_MASK;
+	pt = ENTRY_TO_PTR(pt);
 	if (!pt) {
 		/* physical address of 0x0, nothing to delete */
 		return;
@@ -117,7 +117,7 @@ static void delete_pdir(phys_addr_t pd)
 		return;
 	}
 
-	pd &= ~0x1FFFFFULL;
+	pd &= ENTRY_TO_PTR(pd);
 	if (!pd) {
 		/* physical address of 0x0, nothing to delete */
 		return;
@@ -412,8 +412,46 @@ pmap_t pmap_create(void)
 	return pmap;
 }
 
+static void delete_pdpt(phys_addr_t pd)
+{
+	if (pd & PTE_PAGESIZE) {
+		/* this entry points to a hugepage, nothing to delete */
+		return;
+	}
+
+	pd &= ENTRY_TO_PTR(pd);
+	if (!pd) {
+		/* physical address of 0x0, nothing to delete */
+		return;
+	}
+
+	struct pdpt *pdpt = vm_phys_to_virt(ENTRY_TO_PTR(pd));
+	for (int i = 0; i < 512; i++) {
+		if (pdpt->p_pages[i] & PTE_PAGESIZE) {
+			/* this is a hugepage, there is nothing to delete */
+			continue;
+		}
+
+		if (!pdpt->p_entries[i]) {
+			continue;
+		}
+
+		delete_ptab(pdpt->p_entries[i]);
+	}
+
+	kfree(pdpt);
+}
+
 void pmap_destroy(pmap_t pmap)
 {
+	struct pml4t *pml4t = vm_phys_to_virt(ENTRY_TO_PTR(pmap));
+	for (unsigned int i = 0; i < 256; i++) {
+		if (pml4t->p_entries[i]) {
+			delete_pdpt(pml4t->p_entries[i]);
+		}
+	}
+
+	kfree(pml4t);
 }
 
 static void log_fault(virt_addr_t fault_addr, enum pmap_fault_flags flags)