Enabled paging

12 files changed, 141 insertions, 22 deletions

diff --git a/src/boot/boot.s b/src/boot/boot.s
index dbb4052..51bef8f 100644
--- a/src/boot/boot.s
+++ b/src/boot/boot.s
@@ -30,6 +30,10 @@ idtr:
   dw 0
   dd 0
 
+global page_ptr
+page_ptr:
+  dd 0
+
 global _start:function (_start.end - _start)
 _start:
   mov esp, stack_top
@@ -37,7 +41,7 @@ _start:
   extern get_gdtr
   call get_gdtr
   cli
-  lgdt	[gdtr]
+  lgdt [gdtr]
   mov eax, cr0
   or al, 1
   mov cr0, eax
@@ -50,6 +54,15 @@ _start:
   sti
   xchg bx, bx
 
+  extern genDirs
+  extern page_dir
+  call genDirs
+  mov eax, page_dir
+  mov cr3, eax
+  mov eax, cr0
+  or eax, 0x80000001
+  mov cr0, eax
+
   [bits 32]
   extern kernel_main
   call kernel_main
diff --git a/src/include/exceptions.h b/src/include/exceptions.h
index 1da8348..fddc66e 100644
--- a/src/include/exceptions.h
+++ b/src/include/exceptions.h
@@ -1,2 +1,2 @@
 #pragma once
-__attribute__((noreturn)) void panic(const char *msg);
+__attribute__((noreturn)) void panic(const char *msg, ...);
diff --git a/src/include/paging.h b/src/include/paging.h
new file mode 100644
index 0000000..11578c2
--- /dev/null
+++ b/src/include/paging.h
@@ -0,0 +1,13 @@
+#ifndef __PAGING_H
+#define __PAGING_H
+#include <stdint.h>
+typedef uint32_t Page_Directory;
+typedef uint32_t Page_Table;
+
+Page_Directory make_pagedir(Page_Table *addr, uint8_t flags);
+Page_Directory make_pagetable(uint32_t addr, uint8_t flags);
+void *get_physaddr(void *virtualaddr);
+void map_page(void *physaddr, void *virtualaddr, uint8_t flags);
+void genDirs();
+void *kalloc_init();
+#endif // !__PAGING_H
diff --git a/src/include/print.h b/src/include/print.h
index 7ef7fa3..63f5724 100644
--- a/src/include/print.h
+++ b/src/include/print.h
@@ -1,5 +1,6 @@
 #pragma once
 
+#include <stdarg.h>
 #include <stdint.h>
 
 // Define colors for printing
@@ -30,3 +31,4 @@ void print_char(char);
 int print_str(char *);
 void print_set_color(uint8_t, uint8_t);
 int printf(const char *, ...);
+int printf_logic(const char *, va_list args);
diff --git a/src/kernel/exceptions.c b/src/kernel/exceptions.c
index 11e45fb..bd81c08 100644
--- a/src/kernel/exceptions.c
+++ b/src/kernel/exceptions.c
@@ -1,9 +1,14 @@
 #include "print.h"
+#include <stdarg.h>
 
-__attribute__((noreturn)) void panic(const char *msg) {
+__attribute__((noreturn)) void panic(const char *msg, ...) {
+    va_list args;
+    va_start(args, msg);
     print_set_color(PRINT_COLOR_BLACK, PRINT_COLOR_RED);
     print_clear();
-    printf("PANIC!!\n\t%s", msg);
+    printf("PANIC!!\n\t");
+    printf_logic(msg, args);
+    va_end(args);
     __asm__ volatile("cli; hlt");
     while (1)
         ;
diff --git a/src/kernel/kernel.c b/src/kernel/kernel.c
index d960c20..c103476 100644
--- a/src/kernel/kernel.c
+++ b/src/kernel/kernel.c
@@ -1,9 +1,8 @@
+#include "exceptions.h"
 #include "gdt.h"
 #include "isr.h"
+#include "paging.h"
 #include "print.h"
-extern GDTR_t idtr;
-extern GDTR_t gdtr;
-
 #if defined(__linux__)
 #error "Not using cross compiler!"
 #endif
@@ -14,6 +13,9 @@ extern GDTR_t gdtr;
 #endif
 
 void motd() { printf("Welcome to gftos!\n=================\n"); }
+extern Page_Table pgtable[1024];
+extern Page_Directory page_dir[1024];
+extern GDT_t table;
 
 void kernel_main(void) {
     PIC_init(0x20, 0xA0);
@@ -22,6 +24,9 @@ void kernel_main(void) {
     print_set_color(PRINT_COLOR_PINK, PRINT_COLOR_DARK_GRAY);
     print_clear();
     motd();
+    printf("Page Directory: %x\n", (Page_Directory *)page_dir[1023]);
+    printf("Page Table: %x\n", (Page_Table *)pgtable);
+    printf("GDT: %x\n", table);
     for (;;) {
         update_cursor();
         asm("hlt");
diff --git a/src/kernel/paging/mmap.c b/src/kernel/paging/mmap.c
new file mode 100644
index 0000000..662c2cd
--- /dev/null
+++ b/src/kernel/paging/mmap.c
@@ -0,0 +1,3 @@
+#include "paging.h"
+// TODO: write a frame page allocator to allocate page tables into virtual
+// memory
diff --git a/src/kernel/paging/page_alloc.c b/src/kernel/paging/page_alloc.c
new file mode 100644
index 0000000..3c3e28f
--- /dev/null
+++ b/src/kernel/paging/page_alloc.c
@@ -0,0 +1,5 @@
+#include "paging.h"
+#include <stddef.h>
+#include <stdint.h>
+extern uint32_t endkernel;
+// TODO:
diff --git a/src/kernel/paging/paging.c b/src/kernel/paging/paging.c
new file mode 100644
index 0000000..6a482c8
--- /dev/null
+++ b/src/kernel/paging/paging.c
@@ -0,0 +1,67 @@
+#include "paging.h"
+#include "exceptions.h"
+#include <stdint.h>
+extern uint32_t endkernel;
+
+Page_Directory make_pagedir(Page_Table *addr, uint8_t flags) {
+    return ((uint32_t)addr & 0xFFFFF000) | flags;
+}
+
+Page_Table make_pagetable(uint32_t addr, uint8_t flags) {
+    return ((uint32_t)addr & 0xFFFFF000) | flags;
+}
+
+Page_Directory page_dir[1024] __attribute__((aligned(4096)));
+Page_Table pgtable[1024] __attribute__((aligned(4096)));
+
+void idpaging(uint32_t *first_pte, uint32_t from, int size) {
+    for (; size > 0; from += 4096, size -= 4096, first_pte++) {
+        *first_pte = make_pagetable(from, 3); // mark page present.
+    }
+}
+
+void genDirs() {
+    for (int i = 0; i < 1024; i++) {
+        page_dir[i] = make_pagedir(0x0, 2);
+        for (int j = 0; j < 1024; j++)
+            ((uint32_t *)(page_dir[i] & 0xFFFFF000))[j] &= 0xFFFFFFFE;
+    }
+
+    page_dir[1023] = make_pagetable((uint32_t)page_dir, 3);
+
+    idpaging(&pgtable[0], 0x0, 1024 * 0x800);
+    page_dir[0] = make_pagedir(pgtable, 3);
+}
+
+void *get_physaddr(void *virtualaddr) {
+    unsigned long pdindex = (unsigned long)virtualaddr >> 22;
+    unsigned long ptindex = (unsigned long)virtualaddr >> 12 & 0x03FF;
+
+    unsigned long *pd = (unsigned long *)page_dir;
+    if (!(pd[pdindex] & 1))
+        panic("Unimplemented - getphysaddr - pd[%d]", pdindex);
+
+    unsigned long *pt = ((unsigned long *)0xFFC00000) + (0x400 * pdindex);
+    if (!(pt[ptindex] & 1))
+        panic("Unimplemented - getphysaddr - pt[%d]", ptindex);
+
+    return (void *)((pt[ptindex] & ~0xFFF) +
+                    ((unsigned long)virtualaddr & 0xFFF));
+}
+
+void map_page(void *physaddr, void *virtualaddr, uint8_t flags) {
+    unsigned long pdindex = (unsigned long)virtualaddr >> 22;
+    unsigned long ptindex = (unsigned long)virtualaddr >> 12 & 0x03FF;
+
+    unsigned long *pd = (unsigned long *)page_dir;
+    if (!(pd[pdindex] & 1)) {
+        pd[pdindex] =
+            make_pagedir((uint32_t *)0xFFC00000 + (0x400 * pdindex), 3);
+    }
+
+    unsigned long *pt = ((unsigned long *)0xFFC00000) + (0x400 * pdindex);
+    if (pt[ptindex] & 1)
+        panic("Unimplemented - map_page - pt[%d]", ptindex);
+
+    pt[ptindex] = ((unsigned long)physaddr) | (flags & 0xFFF) | 0x01; // Present
+}
diff --git a/src/kernel/print.c b/src/kernel/print.c
index f635fe5..937a8aa 100644
--- a/src/kernel/print.c
+++ b/src/kernel/print.c
@@ -129,14 +129,10 @@ void print_set_color(uint8_t foreground, uint8_t background) {
     color = foreground + (background << 4);
 }
 
-int printf(const char *str, ...) {
-    va_list args;
-    va_start(args, str);
-    char temp_str[256] = "";
+int printf_logic(const char *str, va_list args) {
     int len = 0;
-
-    size_t i;
-    for (i = 0; str[i] != '\0'; ++i) {
+    char temp_str[256] = "";
+    for (int i = 0; str[i] != '\0'; ++i) {
         if (str[i] == '%') {
             switch (str[++i]) {
             case 'i':
@@ -164,6 +160,13 @@ int printf(const char *str, ...) {
         }
         print_char(str[i]);
     }
+    return len;
+}
+
+int printf(const char *str, ...) {
+    va_list args;
+    va_start(args, str);
+    int len = printf_logic(str, args);
     va_end(args);
-    return i;
+    return len;
 }
diff --git a/src/kernel/tables/gdt.c b/src/kernel/tables/gdt.c
index 9c65152..6cd05a8 100644
--- a/src/kernel/tables/gdt.c
+++ b/src/kernel/tables/gdt.c
@@ -7,8 +7,8 @@ void get_gdtr() {
     uint32_t base = (uint32_t)table;
 
     table[0] = make_descriptor(base, 0, 0);
-    table[1] = make_descriptor(base, 0x3FFFF, make_code(0, 0, 1));
-    table[2] = make_descriptor(base, 0x3FFFF, make_data(0, 0, 1));
+    table[1] = make_descriptor(base, 0xFFFFF, make_code(0, 0, 1));
+    table[2] = make_descriptor(base, 0xFFFFF, make_data(0, 0, 1));
 
     gdtr.size = sizeof(Segment_Descriptor_t) * 3 - 1;
     gdtr.offset = base;
diff --git a/src/linker.ld b/src/linker.ld
index 8a9d5f8..770b955 100644
--- a/src/linker.ld
+++ b/src/linker.ld
@@ -10,15 +10,16 @@ ENTRY (_start)
  */
 SECTIONS
 {
-  /* Put sections at 1MiB, the conventional place for kernels to be 
+  /* Put sections at 1MiB, the conventional place for kernels to be
    * loaded at by the bootloader. */
   . = 1M;
 
-  /* First, put the multiboot header. It is required to be put 
-   * VERY early in the image or the bootloader wont recognize the file 
+  /* First, put the multiboot header. It is required to be put
+   * VERY early in the image or the bootloader wont recognize the file
    * format. Next, we will put the .text section*/
   .text BLOCK(4K) : ALIGN(4K)
   {
+    text_start = .;
     *(.multiboot)
     *(.text)
   }
@@ -31,14 +32,16 @@ SECTIONS
   .data BLOCK(4K) : ALIGN(4K)
   {
     *(.data)
+    end_data = .;
   }
   /* Read write data (uninitialized) and stack */
   .bss BLOCK(4K) : ALIGN(4K)
   {
+    sbss = .;
     *(COMMON)
     *(.bss)
+    ebss = .;
+    endkernel = .;
   }
 
-  /* The compiler may produce other sections, but they will be put in
-   * a section with the same name by default. Add stuff here as needed */
 }