Some changes to names and a convenience ASM function

asm.h now can nuke the TLB by refreshing the PD.
also changed some symbols to more accurately represent what they are
for, such as the kernelspace page tables or the global PD.

include/asm.h

@@ -10,5 +10,6 @@
 
 void outb(uint16_t port, uint8_t data);
 uint8_t inb(uint16_t port);
+void cr3_reload();
 
 #endif

include/virtmem.h

@@ -0,0 +1,11 @@
+#ifndef VIRTMEM_H
+#define VIRTMEM_H
+#include <stdint.h>
+
+
+extern uint32_t global_page_dir;
+extern uint32_t kernel_pagetable;
+
+
+
+#endif

src/asm.s

@@ -1,4 +1,4 @@
-global outb, inb
+global outb, inb, invlpg
 section .text
     outb:
         mov dx, [esp+4]
@@ -11,3 +11,8 @@ section .text
         mov dx, [esp+4]
         in al, dx
         ret
+
+    cr3_reload:
+        mov eax, cr3
+        mov cr3, eax
+        ret

src/physmem.c

@@ -21,15 +21,11 @@ unsigned int build_bitmap(mb_mmap_entry_t* mmap, int mmap_size) {
     //rather important global pointer to the bitmap
     pmem_bitmap = (&_kernel_end);
     
-
-
     //some variables
     int mmap_end = (uint32_t)mmap + mmap_size;
     unsigned int pages_allocated = 0;    
     uint32_t max_memory = 0;
 
-
-
     //How much memory do we even have? Find the highest usable mmap region, and that'll be our bitmap size.
     for(mb_mmap_entry_t* mmap_walk = mmap;
         (int)mmap_walk < mmap_end;

src/start.s

@@ -25,9 +25,9 @@ section .tss align=16 nobits
         resb 104
 
 section .bootstrap_tables nobits align=4096
-    bootstrap_PD:
+    global_page_dir:
         resb 4096
-    bootstrap_PT:
+    kernel_pagetable:
         resb 4096
 
 ;Actual code. Entry point goes here!
@@ -60,7 +60,7 @@ section .lower_text exec
         mov ecx, 0x0
         ;edi = our pointer to the current page table entry. Array of 4byte entries. It's at, of course, where we put it earlier.
         ;Worth noting that it's actually physically at ~1M with the kernel. The pointer, however, is virtually inclined. So we need to adjust.
-        mov edi, bootstrap_PT - 0xC0000000
+        mov edi, kernel_pagetable - 0xC0000000
 
         page_alloc_loop:
             ;If we're lower than our kernel, skip this page. If we've passed our kernel, we're done mapping.
@@ -87,15 +87,15 @@ section .lower_text exec
 
         page_alloc_done:
         ;By now we've mapped the kernel in a page table! Let's map VGA too, we'll need that address later.
-        mov dword [bootstrap_PT - 0xC0000000 + 1023 * 4], 0x000B8000 | 0x27
+        mov dword [kernel_pagetable - 0xC0000000 + 1023 * 4], 0x000B8000 | 0x27
         
         ;We have our page tables mapped to the phys addr of kernel + VGA. Time to add them to our page directory!
         ;First identity maps, second maps to higher half.
-        mov dword [bootstrap_PD - 0xC0000000], bootstrap_PT - 0xC0000000 + 0x003
-        mov dword [bootstrap_PD - 0xC0000000 + 4 * (0xC0000000 >> 22)], bootstrap_PT - 0xC0000000 + 0x003
+        mov dword [global_page_dir - 0xC0000000], kernel_pagetable - 0xC0000000 + 0x003
+        mov dword [global_page_dir - 0xC0000000 + 4 * (0xC0000000 >> 22)], kernel_pagetable - 0xC0000000 + 0x003
 
         ;Let's set it! You do this with cr3.
-        mov ecx, bootstrap_PD - 0xC0000000
+        mov ecx, global_page_dir - 0xC0000000
         mov cr3, ecx
  
         ;Enable paging in cr0