kernel: virtual_mm: Implement paging, properly

2 files changed, 40 insertions, 29 deletions

diff --git a/kernel/include/mm/virtual_mm.h b/kernel/include/mm/virtual_mm.h
index 4873a30..92ffd3c 100644
--- a/kernel/include/mm/virtual_mm.h
+++ b/kernel/include/mm/virtual_mm.h
@@ -29,37 +29,37 @@
 #define PAGE_TABLE_INDEX(virtual_address) ((virtual_address >> 12) & 0x3ff)
 
 #define SET_PDE_PRESENT(x) x
-#define SET_PDE_WRITABLE(x) (x << 1)
-#define SET_PDE_USER(x) (x << 2)
-#define SET_PDE_WRITETHROUGH(x) (x << 3)
-#define SET_PDE_CACHE_DISABLE(x) (x << 4)
-#define SET_PDE_ACCESSED(x) (x << 5)
+#define SET_PDE_WRITABLE(x) ((x) << 1)
+#define SET_PDE_USER(x) ((x) << 2)
+#define SET_PDE_WRITETHROUGH(x) ((x) << 3)
+#define SET_PDE_CACHE_DISABLE(x) ((x) << 4)
+#define SET_PDE_ACCESSED(x) ((x) << 5)
 /* Never set (reserved by Intel) */
-#define SET_PDE_RESERVED(x) (x << 6)
-#define SET_PDE_PAGE_SIZE(x) (x << 7)
+#define SET_PDE_RESERVED(x) ((x) << 6)
+#define SET_PDE_PAGE_SIZE(x) ((x) << 7)
 /* NOTE: Unused by the CPU, free to be used by us! */
-#define SET_PDE_UNUSED(x) (x << 8)
+#define SET_PDE_UNUSED(x) ((x) << 8)
 /* Page table address */
-#define SET_PDE_FRAME(x) (x << 12)
+#define SET_PDE_FRAME(x) ((x) << 12)
 
-#define GET_PDE_FRAME(x) (*x >> 12)
+#define GET_PDE_FRAME(x) ((*x) >> 12)
 
 #define SET_PTE_PRESENT(x) x
-#define SET_PTE_WRITABLE(x) (x << 1)
-#define SET_PTE_USER(x) (x << 2)
-#define SET_PTE_WRITETHROUGH(x) (x << 3)
-#define SET_PTE_CACHE_DISABLE(x) (x << 4)
-#define SET_PTE_ACCESSED(x) (x << 5)
-#define SET_PTE_DIRTY(x) (x << 6)
-#define SET_PTE_PAT(x) (x << 7)
-#define SET_PTE_GLOBAL(x) (x << 8)
+#define SET_PTE_WRITABLE(x) ((x) << 1)
+#define SET_PTE_USER(x) ((x) << 2)
+#define SET_PTE_WRITETHROUGH(x) ((x) << 3)
+#define SET_PTE_CACHE_DISABLE(x) ((x) << 4)
+#define SET_PTE_ACCESSED(x) ((x) << 5)
+#define SET_PTE_DIRTY(x) ((x) << 6)
+#define SET_PTE_PAT(x) ((x) << 7)
+#define SET_PTE_GLOBAL(x) ((x) << 8)
 /* NOTE: Unused by the CPU, free to be used by us! */
-#define SET_PTE_UNUSED(x) (x << 9)
+#define SET_PTE_UNUSED(x) ((x) << 9)
 /* MAX: 0xFFFFF000 */
-#define SET_PTE_FRAME(x) (x << 12)
+#define SET_PTE_FRAME(x) ((x) << 12)
 
-#define PTE_IS_PRESENT(x) (x & 1)
-#define GET_PTE_FRAME(x) (*x >> 12)
+#define PTE_IS_PRESENT(x) ((x) &1)
+#define GET_PTE_FRAME(x) ((*x) >> 12)
 
 #define ADD_ATTRIB(entry, attribute) (*entry |= (attribute))
 
diff --git a/kernel/mm/virtual_mm/virtual_mm.c b/kernel/mm/virtual_mm/virtual_mm.c
index d8d3d70..cfa32e1 100644
--- a/kernel/mm/virtual_mm/virtual_mm.c
+++ b/kernel/mm/virtual_mm/virtual_mm.c
@@ -33,7 +33,7 @@ uint32_t *current_page_directory = 0;
 ALWAYS_INLINE void
 virtual_mm_load_page_directory(uint32_t *page_directory)
 {
-  __asm__("movl %0, %%eax" ::"r"(page_directory));
+  __asm__("movl %0, %%cr3" ::"r"(page_directory));
 }
 
 bool
@@ -64,10 +64,10 @@ virtual_mm_initialize(void)
     ASSERT_NOT_REACHED();
 
   for (uint32_t i = 0; i < 1024; i++)
-    table[i] = 0;
+    table[i] = 0x2;
 
   /* Identity map the first 4MiB (maps 4KiB 1024 times) */
-  for (uint32_t i = 0, physical_addr = 0, virtual_addr = 0; i < 1024;
+  /* for (uint32_t i = 0, physical_addr = 0, virtual_addr = 0; i < 1024;
        i++, physical_addr += 4096, virtual_addr += 4096) {
     uint32_t pt_entry = 0;
     ADD_ATTRIB(&pt_entry, SET_PTE_PRESENT(1));
@@ -76,7 +76,16 @@ virtual_mm_initialize(void)
 
     table[PAGE_TABLE_INDEX(virtual_addr)] = pt_entry;
   }
-  printk("debug", "Page table is at: 0x%x", table);
+  printk("debug", "Page table is at: 0x%x", table); */
+
+  for (uint32_t i = 0; i < 1024; i++) {
+    uint32_t pt_entry = 0;
+    ADD_ATTRIB(&pt_entry, SET_PTE_PRESENT(1));
+    ADD_ATTRIB(&pt_entry, SET_PTE_WRITABLE(1));
+    ADD_ATTRIB(&pt_entry, SET_PTE_FRAME(i));
+
+    table[i] = pt_entry;
+  }
 
   uint32_t *page_directory = physical_mm_allocate_block();
   if (!page_directory)
@@ -85,13 +94,15 @@ virtual_mm_initialize(void)
   for (uint32_t i = 0; i < 1024; i++)
     page_directory[i] = 0;
 
-  uint32_t *pd_entry = &page_directory[PAGE_DIRECTORY_INDEX(0)];
+  /* uint32_t *pd_entry = &page_directory[0];
   ADD_ATTRIB(pd_entry, SET_PDE_PRESENT(1));
   ADD_ATTRIB(pd_entry, SET_PDE_WRITABLE(1));
-  ADD_ATTRIB(pd_entry, SET_PDE_FRAME((uint32_t) table));
+  ADD_ATTRIB(pd_entry, SET_PDE_FRAME((uint32_t) table)); */
+  page_directory[0] = ((uint32_t) table) | 3;
 
   printk("debug", "Page directory is at: 0x%x", page_directory);
-  printk("debug", "pd_entry: 0x%x", pd_entry);
+  // printk("debug", "pd_entry: 0x%x", pd_entry);
+  printk("debug", "513th entry: 0x%x", table[513]);
 
   virtual_mm_switch_page_directory(page_directory);
   virtual_mm_enable_paging();