Merge branch 'GDTLDT' into 'master'

Gdtldt

Still some unexplained weird things, but works.

See merge request !8

src/gdt.c

+#include "gdt.h"
+#include "string.h"
+#include "serial.h"
+//#include "term.h"
+
+uint16_t gdt_limit;
+uint32_t gdt_base;
+
+gdt_desc _gdt [MAX_GDT_DESC];
+
+#define set_cs( cs ) asm volatile ( "ljmp %0, $1337f \n\t 1337: \n\t" :: "i"(cs) )
+void gdt_install(){
+    struct{
+        uint16_t limit;
+	uint32_t base;
+    }__attribute__((packed)) gdtr;
+    gdtr.limit = gdt_limit;
+    gdtr.base = gdt_base;
+    asm volatile ("lgdt (%0)": :"r"(&gdtr));
+    set_cs(8);
+    asm volatile("mov $0x10, %ax;               \
+                 mov %ax, %ds;			\
+                 mov %ax, %es;			\
+                 mov %ax, %fs;			\
+                 mov %ax, %gs;			\
+                 mov %ax, %ss;");
+    strlen("");
+}
+void gdt_set_desc(uint32_t i, uint64_t base, uint64_t limit, uint8_t access, uint8_t gran){
+    if (i > MAX_GDT_DESC)
+        return;
+    memset ((void*)&_gdt[i], 0, sizeof (gdt_desc));
+    
+    _gdt[i].low_base  = (uint16_t)(base & 0xffff);
+    _gdt[i].mid_base  = (uint8_t)((base >> 16) & 0xff);
+    _gdt[i].high_base = (uint8_t)((base >> 24) & 0xff);
+    _gdt[i].lim	    = (uint16_t)(limit & 0xffff);
+    
+    _gdt[i].flags = access;
+    _gdt[i].gran = (uint8_t)((limit >> 16) & 0x0f);
+    _gdt[i].gran |= gran & 0xf0;
+}
+gdt_desc* gdt_get_desc (int i) {
+    if (i > MAX_GDT_DESC)
+	return 0;
+    return &_gdt[i];
+}
+int gdt_init() {
+    gdt_limit = (sizeof (gdt_desc) * MAX_GDT_DESC)-1;
+    gdt_base = (uint32_t)&_gdt[0];
+    //null
+    gdt_set_desc(0, 0, 0, 0, 0);
+    //code
+    gdt_set_desc(1,0,0xffffffff, GDT_RW|GDT_EXE|GDT_CDT|GDT_MEM, GDT_GR_PG|GDT_GR_32|GDT_GR_HI);
+    //data
+    gdt_set_desc(2,0,0xffffffff, GDT_RW|GDT_CDT|GDT_MEM, GDT_GR_PG|GDT_GR_32|GDT_GR_HI);
+    //serial_writestring("gdt filled, now installing\n");
+    gdt_install();
+    return 0;
+}

src/gdt.h

+#ifndef _GDT_INC
+#define _GDT_INC
+
+#include <stdint.h>
+
+#define MAX_GDT_DESC 3
+#define GDT_ACC 0x0001
+#define GDT_RW  0x0002
+#define GDT_DIR 0x0004
+#define GDT_EXE	0x0008
+#define GDT_CDT 0x0010
+#define GDT_DPL	0x0060
+#define GDT_MEM	0x0080
+
+#define GDT_GR_HI 0x0f
+#define GDT_GR_OS 0x10
+#define GDT_GR_32 0x40
+#define GDT_GR_PG 0x80
+
+typedef struct{
+    uint16_t lim;
+    uint16_t low_base;
+    uint8_t  mid_base;
+    uint8_t  flags;
+    uint8_t  gran;
+    uint8_t  high_base;
+} __attribute__((packed)) gdt_desc;
+
+extern void gdt_set_desc(uint32_t i, uint64_t base, uint64_t limit, uint8_t access, uint8_t gran);
+extern gdt_desc* gdt_get_desc(int i);
+extern int gdt_init();
+
+#endif

src/idt.c

+#include "idt.h"
+#include "string.h"
+#include "serial.h"
+
+uint16_t idt_limit;
+uint32_t idt_base;
+
+idt_desc _idt [MAX_IDT_INT];
+
+void idt_install() {
+    struct{
+        uint16_t limit;
+        uint32_t base;
+    } __attribute__((packed)) idtr;
+    idtr.limit = idt_limit;
+    idtr.base = idt_base;
+    char f[20];
+    itoa(idtr.limit, f);
+    itoa(idtr.base, f);
+    asm volatile ("lidt (%0)": :"r"(&idtr));
+}
+
+static void default_handler () {
+    //DEBUG OUTPUT MAYBE?
+    serial_writestring("int caught\n");
+    return;
+}
+
+idt_desc* get_ir (uint32_t i) {
+    if (i>MAX_IDT_INT)
+	return 0;
+    return &_idt[i];
+}
+
+int install_ir (uint32_t i, uint16_t flags, uint16_t code_sel, IRQ_HANDLER irq) {
+    if (i>MAX_IDT_INT)
+	return 0;
+    if (!irq)
+	return 0;
+    uint64_t uiBase = (uintptr_t)(&(*irq));
+    _idt[i].low_base  = (uint16_t)(uiBase & 0xffff);
+    _idt[i].high_base = (uint16_t)((uiBase >> 16) & 0xffff);
+    _idt[i].reserved  = 0;
+    _idt[i].flags	    = (uint8_t)(flags);
+    _idt[i].code_sel  = code_sel;
+    return 0;
+}
+
+int idt_init (uint16_t code_sel) {
+    idt_limit = sizeof (idt_desc) * MAX_IDT_INT -1;
+    idt_base  = (uint32_t)&_idt[0];
+    memset ((void*)&_idt[0], 0, sizeof (idt_desc) * MAX_IDT_INT-1);
+    for (int i=0; i<MAX_IDT_INT; i++)
+	install_ir (i, IDT_PR|IDT_32,code_sel,(IRQ_HANDLER)default_handler);
+    idt_install();
+    char f[20];
+    itoa((uintptr_t)&_idt,f);
+    //serial_writestring(f);
+    return 0;
+}

src/idt.h

+#ifndef _IDT_INC
+#define _IDT_INC
+
+#include <stdint.h>
+
+#define MAX_IDT_INT 256
+
+#define IDT_16 0x06
+#define IDT_32 0x0E
+#define IDT_R1 0x40
+#define IDT_R2 0x20
+#define IDT_R3 0x60
+#define IDT_PR 0x80
+
+typedef void (*IRQ_HANDLER)(void);
+
+typedef struct {
+    uint16_t low_base;
+    uint16_t code_sel;
+    uint8_t  reserved;
+    uint8_t  flags;
+    uint16_t high_base;
+}__attribute__((packed)) idt_desc;
+
+extern idt_desc* get_ir (uint32_t i);
+extern int install_ir (uint32_t i, uint16_t flags, uint16_t code_sel, IRQ_HANDLER);
+extern int idt_init (uint16_t code_sel);
+
+#endif

src/kern.c

@@ -2,9 +2,12 @@
 #include <stddef.h>
 #include <stddef.h>
 #include <stdint.h>
 #include <stdint.h>
 
 
+#include "string.h"
 #include "serial.h"
 #include "serial.h"
 #include "term.h"
 #include "term.h"
 #include "mem.h"
 #include "mem.h"
+#include "gdt.h"
+#include "idt.h"
 
 
 #if defined(__cplusplus)
 #if defined(__cplusplus)
 extern "C" /* Use C linkage for kernel_main. */
 extern "C" /* Use C linkage for kernel_main. */
@@ -13,14 +16,16 @@ void kernel_main() {
     /* Initialize terminal and serial interfaces */
     /* Initialize terminal and serial interfaces */
     terminal_initialize();
     terminal_initialize();
     serial_init();
     serial_init();
+    gdt_init();
+    idt_init(0x8);
 
 
 	/* Since there is no support for newlines in terminal_putchar
 	/* Since there is no support for newlines in terminal_putchar
          * yet, '\n' will produce some VGA specific character instead.
          * yet, '\n' will produce some VGA specific character instead.
          * This is normal.
          * This is normal.
          */
          */
-    serial_writestring("First Serial Test!\n");
+    serial_writestring("IDT initialized\n");
     terminal_writestring("Hello, kernel World!\n");
     terminal_writestring("Hello, kernel World!\n");
-    serial_writestring("Second Serial Test\n");
+    //serial_writestring("Second Serial Test\n");
 
 
     // Enable paging of memory. For now there is only one virtual
     // Enable paging of memory. For now there is only one virtual
     // memory space defined by page_dir
     // memory space defined by page_dir
@@ -31,4 +36,7 @@ void kernel_main() {
     enablePaging();
     enablePaging();
 
 
     serial_writestring("Finished Initilizing memory\n");
     serial_writestring("Finished Initilizing memory\n");
+    asm ("int $0x80");
+    asm ("int $0x90");
+    asm ("hlt");
 }
 }

src/makefile

-C=/home/adam/college/kernel/cross/bin/i686-elf-gcc
+C=i686-elf-gcc
 
 
 all:
 all:
 	/usr/bin/nasm -felf32 head.asm -o boot.o
 	/usr/bin/nasm -felf32 head.asm -o boot.o

src/string.c

+#include "string.h"
+
+void *memset(void *s, int c, size_t n){
+    unsigned char* p=s;
+    while(n--)
+	*p++=(unsigned char) c;
+    return s;
+}
+
+void itoa(int n, char s[])
+ {
+     int i, sign;
+     
+     if ((sign = n) < 0)  /* record sign */
+         n = -n;          /* make n positive */
+     i = 0;
+     do {       /* generate digits in reverse order */
+         s[i++] = n % 10 + '0';   /* get next digit */
+     } while ((n /= 10) > 0);     /* delete it */
+     if (sign < 0)
+         s[i++] = '-';
+     s[i] = '\0';
+     //reverse(s);
+ }
+
+size_t strlen(const char* str) {
+    size_t ret = 0;
+    while ( str[ret] != 0 )
+	ret++;
+    return ret;
+}

src/string.h

+#ifndef _STRING_INC
+#define _STRING_ING
+#include<stddef.h>
+
+void* memset(void *s, int c, size_t n);
+void itoa(int n, char s[]);
+size_t strlen(const char* str);
+
+#endif

src/term.c

@@ -16,13 +16,6 @@ uint16_t make_vgaentry(char c, uint8_t color) {
     return c16 | color16 << 8;
     return c16 | color16 << 8;
 }
 }
 
 
-size_t strlen(const char* str) {
-	size_t ret = 0;
-	while ( str[ret] != 0 )
-		ret++;
-	return ret;
-}
-
 static const size_t VGA_WIDTH = 80;
 static const size_t VGA_WIDTH = 80;
 static const size_t VGA_HEIGHT = 25;
 static const size_t VGA_HEIGHT = 25;
 
 

src/term.h

@@ -6,7 +6,7 @@
 
 
 #include <stdint.h>
 #include <stdint.h>
 #include <stddef.h>
 #include <stddef.h>
-
+#include "string.h"
 /* Hardware text mode color constants. */
 /* Hardware text mode color constants. */
 enum vga_color {
 enum vga_color {
     COLOR_BLACK = 0,
     COLOR_BLACK = 0,
@@ -29,7 +29,6 @@ enum vga_color {
 
 
 uint8_t make_color(enum vga_color fg, enum vga_color bg);
 uint8_t make_color(enum vga_color fg, enum vga_color bg);
 uint16_t make_vgaentry(char c, uint8_t color);
 uint16_t make_vgaentry(char c, uint8_t color);
-size_t strlen(const char* str);
 
 
 void terminal_initialize();
 void terminal_initialize();
 void terminal_setcolor(uint8_t color);
 void terminal_setcolor(uint8_t color);