better page table entry masks

2 files changed, 11 insertions, 8 deletions

diff --git a/api/kernel/memory/paging.h b/api/kernel/memory/paging.h
index 25e5eea..3d13eda 100644
--- a/api/kernel/memory/paging.h
+++ b/api/kernel/memory/paging.h
@@ -1,14 +1,17 @@
 #pragma once
 
-#define PAGE_PR 1
-#define PAGE_WR 2
+#define PAGE_PR (1ULL << 0)
+#define PAGE_WR (1ULL << 1)
+#define PAGE_NX (1ULL << 63)
 
 #define PAGE_MAP_LEVELS 4
 #define PAGE_MAP_BITS 9
 #define PAGE_OFFSET_BITS 12
 
+#define PAGE_ADDRESS_MASK   0x0007fffffffff000
+#define PAGE_ATTRIBUTE_MASK 0xf800000000000fff
+
 #define PAGE_TABLE_INDEX_MASK ((1 << PAGE_MAP_BITS) - 1)
-#define PAGE_TABLE_ADDRESS_MASK ~((1 << PAGE_OFFSET_BITS) - 1)
 
 #define page_table_index_bits(l) (PAGE_OFFSET_BITS + PAGE_MAP_BITS * (l - 1))
 #define page_table_index(v, l) ((v >> page_table_index_bits(l)) & PAGE_TABLE_INDEX_MASK)
diff --git a/loader/loader_efi.c b/loader/loader_efi.c
index 63bbaba..6823563 100644
--- a/loader/loader_efi.c
+++ b/loader/loader_efi.c
@@ -34,9 +34,9 @@ static void *get_acpi_rsdp(void);
 enum page_type
 {
     INVALID_PAGE_TYPE = 0x0,
-    CODE_PAGE_TYPE = 0x1,
-    RODATA_PAGE_TYPE = 0x1,
-    DATA_PAGE_TYPE = 0x3
+    CODE_PAGE_TYPE = PAGE_PR,
+    RODATA_PAGE_TYPE = PAGE_PR|PAGE_NX,
+    DATA_PAGE_TYPE = PAGE_PR|PAGE_WR|PAGE_NX
 };
 
 static uint64_t *new_page_table(void)
@@ -64,7 +64,7 @@ static uint64_t *get_page_map(void)
 {
     uint64_t map;
     __asm__("mov %%cr3, %0" : "=r"(map));
-    return (uint64_t *)(map & PAGE_TABLE_ADDRESS_MASK);
+    return (uint64_t *)(map & PAGE_ADDRESS_MASK);
 }
 
 void set_page_map(uint64_t *map)
@@ -92,7 +92,7 @@ static uint64_t *get_page_table(uint64_t *map, uint64_t virt, int level)
         else
         {
             uint64_t next_map_entry = map[page_table_index(virt, i)];
-            next_map_entry &= PAGE_TABLE_ADDRESS_MASK;
+            next_map_entry &= PAGE_ADDRESS_MASK;
             map = (uint64_t *)next_map_entry;
         }
     }