added code to reset segmentation and enable paging; added fmt_xl2a() in kio; added debug prints in k_bootstrap() since kernel is crashing when trying to enable paging

git-svn-id: svn://anubis/hos/trunk@49 5b3e749e-e535-0410-8002-a9bb6afbdfca

kernel/boot/boot.asm

@@ -8,7 +8,7 @@
 %define MULTIBOOT_HEADER_FLAGS      0x00010003
 
 %define VIRTUAL_OFFSET              0xE0000000          ; kernel virtual addr
-%define CONSOLE_MEMORY              VIRTUAL_OFFSET + 0xB8000
+%define CONSOLE_MEMORY              0xB8000
 
 %define PAGE_SIZE                   0x1000              ; 4KB pages
 
@@ -16,7 +16,7 @@
 extern _end, _bss
 
 ; Symbols from C
-extern k_bootstrap, bootstrap_stack
+extern k_bootstrap, bootstrap_stack, mm_gdtr
 
 ;-------------------------------------------------------
 [section .text]
@@ -48,7 +48,7 @@ multiboot_header:
 ;**************************************************************************
 multiboot_entry:
     mov     cx, 0x0700 + 'a'
-    mov     [CONSOLE_MEMORY-VIRTUAL_OFFSET+160*8+0*2], cx
+    mov     [CONSOLE_MEMORY+160*8+0*2], cx
 
     lgdt    [gdtr_tmp32-VIRTUAL_OFFSET]     ; load temporary GDTR
     jmp     KERNEL_CODE_32_TMP_SEG:segmented_start
@@ -67,7 +67,7 @@ segmented_start:
     mov     esp, bootstrap_stack+4096-4     ; set up temporary stack space
 
     mov     cx, 0x0700 + 'b'
-    mov     [CONSOLE_MEMORY+160*8+1*2], cx
+    mov     [CONSOLE_MEMORY+VIRTUAL_OFFSET+160*8+1*2], cx
 
     add     ebx, VIRTUAL_OFFSET
     push    eax                             ; multiboot bootloader magic value
@@ -76,13 +76,37 @@ segmented_start:
     add     esp, 8
 
     mov     cx, 0x0700 + 'e'
-    mov     [CONSOLE_MEMORY+160*8+4*2], cx
+    mov     [CONSOLE_MEMORY+VIRTUAL_OFFSET+160*8+4*2], cx
+
+    lgdt    [mm_gdtr-VIRTUAL_OFFSET]        ; load permanent GDTR
+    jmp     0x8:segmentation_disabled-VIRTUAL_OFFSET
+
+;**************************************************************************
+;* At this point both segmentation and paging are disabled but we can     *
+;* now enable paging                                                      *
+;**************************************************************************
+segmentation_disabled:
+    mov     cx, 0x10
+    mov     ss, cx
+    mov     ds, cx
+    mov     es, cx
+    mov     gs, cx
+    mov     fs, cx
 
     ; at this point paging is still disabled but the PDBR is valid and
     ; points to a page directory that has all of RAM mapped to the
     ; beginning of the kernel's virtual address space, and the entire
     ; kernel mapped in above 0xE000_0000.
 
+    ; turn on paging
+    mov     eax, cr0
+    bts     eax, 31
+    mov     cr0, eax
+
+    ; OK, segmentation is disabled and paging is active!
+    mov     cx, 0x0700 + 'f'
+    mov     [CONSOLE_MEMORY+160*8+5*2], cx
+
 idle_loop:
     hlt
     jmp     idle_loop

kernel/boot/k_bootstrap.cc

@@ -49,6 +49,15 @@ u32_t k_bootstrap(mb_info_t * mb_info, u32_t mb_magic)
     kio_bootstrap();
 
     kprintf("Hello from kprintf()! %d, %x, %u, %l\n", 42, 0xabcd0123, 0xFFFFFFFF, -1234567891234ll);
+
+#if 0
+    kprintf("d1: 0x%X\n", MAKE_DESCRIPTOR(0, 0xFFFFF, 1, 0, 1, 1));
+    kprintf("d2: 0x%X\n", MAKE_DESCRIPTOR(0, 0xFFFFF, 1, 0, 1, 0));
+
+    for (;;)
+        ;
+#endif
+
     return 0;
 }
 

kernel/lang/kio.cc

@@ -12,6 +12,7 @@ static void fmt_u2a(char * buf, unsigned int val);
 static void fmt_ll2a(char * buf, long long val);
 static void fmt_ull2a(char * buf, unsigned long long val);
 static void fmt_x2a(char * buf, unsigned int val);
+static void fmt_xl2a(char * buf, unsigned long long val);
 static void fmt_o2a(char * buf, unsigned int val);
 
 static int cursor_x, cursor_y;
@@ -76,6 +77,10 @@ void kvprintf(const char * fmt, va_list args)
                         fmt_x2a(tmpbuf, va_arg(args, unsigned int));
                         kputs(tmpbuf);
                         break;
+                    case 'X':
+                        fmt_xl2a(tmpbuf, va_arg(args, unsigned long long));
+                        kputs(tmpbuf);
+                        break;
                     case '%':
                         kputc('%');
                         break;
@@ -228,6 +233,26 @@ static void fmt_x2a(char * buf, unsigned int val)
     *buf = '\0';
 }
 
+static void fmt_xl2a(char * buf, unsigned long long val)
+{
+    fmt_x2a(buf, val >> 32);
+    buf += strlen(buf);
+    bool printing = ( (val >> 32) != 0 );
+    for (int s = 28; s >= 0; s -= 4)
+    {
+        unsigned int n = (val >> s) & 0xF;
+        if (n)
+        {
+            printing = true;
+        }
+        if (printing)
+        {
+            *buf++ = "0123456789abcdef"[n];
+        }
+    }
+    *buf = '\0';
+}
+
 static void fmt_o2a(char * buf, unsigned int val)
 {
     bool printing = false;

kernel/lang/string.cc

@@ -12,6 +12,16 @@ void strcpy(char * dst, const char * src)
     *dst = '\0';
 }
 
+u32_t strlen(const char * s)
+{
+    u32_t len = 0;
+    while (*s++)
+    {
+        len++;
+    }
+    return len;
+}
+
 void memcpy(u8_t * dst, u8_t * src, u32_t size)
 {
     for (u32_t n = 0; n < size; n++)

kernel/lang/string.h

@@ -10,6 +10,8 @@ extern "C" {
 
 void strcpy(char * dst, const char * src);
 
+u32_t strlen(const char * s);
+
 void memcpy(u8_t * dst, u8_t * src, u32_t size);
 void memcpyw(u16_t * dst, u16_t * src, u32_t size);
 void memcpyd(u32_t * dst, u32_t * src, u32_t size);

kernel/mm/mm.cc

@@ -15,6 +15,7 @@ static int mm_mmap_num_entries = 0;
 static int mm_num_free_pages = 0;
 u32_t * mm_free_page_ptr = NULL;
 gdtr_t mm_gdtr;
+static u64_t * mm_gdt;
 
 /**************************************************************************
  * This function is run in segmented memory before paging is in effect.   *
@@ -145,12 +146,12 @@ void mm_bootstrap()
 
     /* set up the global descriptor table */
     u32_t gdt_base = mm_page_alloc();
-    u64_t * gdt = (u64_t *) ((u32_t) gdt_base + (u32_t) KERNEL_OFFSET);
+    mm_gdt = (u64_t *) ((u32_t) gdt_base + (u32_t) KERNEL_OFFSET);
-    memsetd((u32_t *) gdt, 0, PAGE_SIZE / 4);
+    mm_gdt[0] = 0x0ull;
-    mm_gdtr.length = PAGE_SIZE - 1;
+    mm_gdt[1] = MAKE_DESCRIPTOR(0, 0xFFFFF, 1, 0, 1, 1);
+    mm_gdt[2] = MAKE_DESCRIPTOR(0, 0xFFFFF, 1, 0, 1, 0);
+    mm_gdtr.length = 3*sizeof(mm_gdt[0]) - 1;
     mm_gdtr.phys_addr = gdt_base;
-    gdt[1] = MAKE_DESCRIPTOR(0, 0xFFFFF, 1, 0, 1, 1);
-    gdt[2] = MAKE_DESCRIPTOR(0, 0xFFFFF, 1, 0, 1, 0);
 
     /* set the page directory base register */
     set_cr3(page_directory);