first real commit

17 files changed, 385 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..2cc6980
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,4 @@
+*~
+*.o
+kappa.iso
+kappa.bin
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..2776f75
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,34 @@
+OBJ = drivers/tty.o kernel/main.o boot/head.o kernel/io.o kernel/gdt-as.o kernel/gdt.o
+CC = gcc
+LD = ld
+INCLUDES = -Idrivers -Ikernel/include
+CFLAGS = -std=gnu99 -ffreestanding -fno-stack-protector -nostdlib -Wall -Wextra -m32 $(INCLUDES)
+
+AS = as
+ASFLAGS=-march=i686 --32
+
+all: kappa.bin
+
+test: iso
+	qemu-system-i386 kappa.iso
+
+iso: kappa.bin
+	mkdir -p isodir
+	mkdir -p isodir/boot
+	cp kappa.bin isodir/efi.img
+	cp kappa.bin isodir/boot/kappa.bin
+	mkdir -p isodir/boot/grub
+	cp cdrom/grub.cfg isodir/boot/grub
+	grub-mkrescue -o kappa.iso isodir
+
+kappa.bin: $(OBJ) $(SOURCES) Makefile
+	$(LD) -T kernel/linker.ld -o kappa.bin -melf_i386 $(OBJ)
+
+%.o: %.c
+	$(CC) $(CFLAGS) -c $< -o $@
+
+%.o: %.S
+	$(AS) $(ASFLAGS) -c $< -o $@
+
+clean:
+	rm -f $(OBJ) kappa.iso kappa.bin
diff --git a/boot/head.S b/boot/head.S
new file mode 100644
index 0000000..864ebeb
--- /dev/null
+++ b/boot/head.S
@@ -0,0 +1,30 @@
+        .set ALIGN,      1<<0
+        .set MEMINFO,    1<<1
+        .set FLAGS,      ALIGN | MEMINFO
+        .set MAGIC,      0x1BADB002 # multiboot magic
+        .set CHECKSUM,   -(MAGIC + FLAGS)
+
+.section .multiboot
+        .align 4
+multiboot_header:
+        .long MAGIC
+        .long FLAGS
+        .long CHECKSUM
+
+.section .stack
+stack_bottom:                   # Stack grows up in addresses, so bottom is
+                                # lower than the top
+        .skip 16384             # 32KB stack
+stack_top:
+
+.section .text
+        .global _start
+        .type _start, @function
+_start:
+        movl $stack_top, %esp
+        call main
+        cli
+        hlt
+.Lhang:                   # Idle
+        jmp .Lhang
+        .size _start, . - _start
diff --git a/drivers/tty.c b/drivers/tty.c
new file mode 100644
index 0000000..e938abd
--- /dev/null
+++ b/drivers/tty.c
@@ -0,0 +1,86 @@
+#include <stdint.h>
+#include "io.h"
+#include "tty.h"
+#include "vga.h"
+
+static int term_x, term_y;
+static uint8_t term_col;
+/* VGA buffer starts at 0xB8000 */
+static uint16_t *term_buf;
+
+void tty_init(void)
+{
+    term_buf = (uint16_t*)0xB8000;
+    term_col = VGA_MAKE_COLOR(VGA_WHITE, VGA_BLACK);
+    tty_clear();
+}
+
+static void move_cursor(uint16_t cursor_idx)
+{
+    outb(0x3D4, 14);
+    outb(0x3D5, cursor_idx >> 8); // high byte
+    outb(0x3D4, 15);
+    outb(0x3D5, cursor_idx); // low byte
+}
+
+static void update_cursor(void)
+{
+    move_cursor(term_y * VGA_WIDTH + term_x);
+}
+
+void tty_clear(void)
+{
+    term_x = 0;
+    term_y = 0;
+    for(int y = 0; y < VGA_HEIGHT; ++y)
+    {
+        for(int x = 0; x < VGA_WIDTH; ++x)
+        {
+            term_buf[y * VGA_WIDTH + x] = VGA_MAKE_ENTRY(' ', term_col);
+        }
+    }
+}
+
+void tty_set_color(uint8_t color)
+{
+    term_col = color;
+}
+
+uint8_t tty_get_color(void)
+{
+    return term_col;
+}
+
+void tty_putchar_at(char ch, uint8_t col, int x, int y)
+{
+    term_buf[y * VGA_WIDTH + x] = VGA_MAKE_ENTRY(ch, col);
+}
+
+void tty_putchar(char ch)
+{
+    if(ch != '\n')
+    {
+        tty_putchar_at(ch, term_col, term_x, term_y);
+        if(++term_x == VGA_WIDTH)
+        {
+            term_x = 0;
+            if(++term_y == VGA_HEIGHT)
+                term_y = 0;
+        }
+    }
+    else
+    {
+        term_x = 0;
+        if(++term_y == VGA_HEIGHT)
+            term_y = 0;
+    }
+    update_cursor();
+}
+
+void tty_puts(const char *str)
+{
+    while(*str)
+    {
+        tty_putchar(*str++);
+    }
+}
diff --git a/drivers/tty.h b/drivers/tty.h
new file mode 100644
index 0000000..0e142c6
--- /dev/null
+++ b/drivers/tty.h
@@ -0,0 +1,9 @@
+#include <stdint.h>
+
+void tty_init(void);
+void tty_clear(void);
+void tty_set_color(uint8_t);
+uint8_t tty_get_color(void);
+void tty_putchar_at(char ch, uint8_t color, int x, int y);
+void tty_putchar(char ch);
+void tty_puts(const char*);
diff --git a/drivers/vga.h b/drivers/vga.h
new file mode 100644
index 0000000..bf13cba
--- /dev/null
+++ b/drivers/vga.h
@@ -0,0 +1,26 @@
+#include <stdint.h>
+
+enum vga_color_t {
+    VGA_BLACK = 0,
+    VGA_BLUE = 1,
+    VGA_GREEN = 2,
+    VGA_CYAN = 3,
+    VGA_RED = 4,
+    VGA_MAGENTA = 5,
+    VGA_BROWN = 6,
+    VGA_LIGHT_GRAY = 7,
+    VGA_DARK_GRAY = 8,
+    VGA_LIGHT_BLUE = 9,
+    VGA_LIGHT_GREEN = 10,
+    VGA_LIGHT_CYAN = 11,
+    VGA_LIGHT_RED = 12,
+    VGA_LIGHT_MAGENTA = 13,
+    VGA_LIGHT_BROWN = 14,
+    VGA_WHITE = 15
+};
+
+#define VGA_WIDTH  80
+#define VGA_HEIGHT 25
+
+#define VGA_MAKE_COLOR(fg, bg) (fg | bg << 4)
+#define VGA_MAKE_ENTRY(ch, col) (((uint16_t)ch)|((uint16_t)col<<8))
diff --git a/kernel/gdt-as.S b/kernel/gdt-as.S
new file mode 100644
index 0000000..7283dc8
--- /dev/null
+++ b/kernel/gdt-as.S
@@ -0,0 +1,16 @@
+        .global gdt_flush
+        .type gdt_flush, @function
+gdt_flush: # prototype: void gdt_flush(uint32_t addr)
+        cli
+        movl 4(%esp), %eax # load the address off the stack (first param)
+        lgdt (%eax)
+        mov $0x10, %ax
+        mov %ax, %ds
+        mov %ax, %es
+        mov %ax, %fs
+        mov %ax, %gs
+        mov %ax, %ss
+        sti
+        jmp .flush
+.flush:
+        ret
diff --git a/kernel/gdt.c b/kernel/gdt.c
new file mode 100644
index 0000000..f9b2d86
--- /dev/null
+++ b/kernel/gdt.c
@@ -0,0 +1,33 @@
+#include "gdt.h"
+
+static void gdt_set_gate(int idx, uint32_t base, uint32_t limit, uint8_t access, uint8_t gran)
+{
+    /* Setup the descriptor base address */
+    gdt[idx].base_low = (base & 0xFFFF);
+    gdt[idx].base_middle = (base >> 16) & 0xFF;
+    gdt[idx].base_high = (base >> 24) & 0xFF;
+
+    /* Setup the descriptor limits */
+    gdt[idx].limit_low = (limit & 0xFFFF);
+    gdt[idx].granularity = ((limit >> 16) & 0x0F);
+
+    /* Finally, set up the granularity and access flags */
+    gdt[idx].granularity |= (gran & 0xF0);
+    gdt[idx].access = access;
+}
+
+void gdt_init(void)
+{
+    gp.limit = (sizeof(struct gdt_entry) * sizeof(gdt)/sizeof(gdt[0])) - 1;
+    gp.base = (uint32_t)&gdt;
+
+    gdt_set_gate(0, 0, 0, 0, 0);
+
+    /* code segment */
+    gdt_set_gate(1, 0, 0xFFFFFFFF, 0x9A, 0xCF);
+
+    /* data segment */
+    gdt_set_gate(2, 0, 0xFFFFFFFF, 0x92, 0xCF);
+
+    gdt_flush((uint32_t)&gp);
+}
diff --git a/kernel/include/gdt.h b/kernel/include/gdt.h
new file mode 100644
index 0000000..e93c92a
--- /dev/null
+++ b/kernel/include/gdt.h
@@ -0,0 +1,23 @@
+#include <stdint.h>
+
+struct gdt_entry {
+    uint16_t limit_low;
+    uint16_t base_low;
+    uint8_t base_middle;
+    uint8_t access;
+    uint8_t granularity;
+    uint8_t base_high;
+} __attribute__((packed));
+
+struct gdt_ptr {
+    uint8_t limit;
+    uint32_t base;
+} __attribute__((packed));
+
+struct gdt_entry gdt[3];
+struct gdt_ptr gp;
+
+/* assembly */
+extern void gdt_flush(struct gdt_ptr*);
+
+void gdt_init(void);
diff --git a/kernel/include/io.h b/kernel/include/io.h
new file mode 100644
index 0000000..c3c735b
--- /dev/null
+++ b/kernel/include/io.h
@@ -0,0 +1,4 @@
+#include <stdint.h>
+void outb(uint16_t port, uint8_t val);
+uint8_t inb(uint16_t port);
+uint16_t inw(uint16_t port);
diff --git a/kernel/io.c b/kernel/io.c
new file mode 100644
index 0000000..9b56b5d
--- /dev/null
+++ b/kernel/io.c
@@ -0,0 +1,19 @@
+#include <stdint.h>
+#include "io.h"
+
+void outb(uint16_t port, uint8_t val)
+{
+    asm volatile ("outb %1, %0": :"dN" (port), "a" (val));
+}
+uint8_t inb(uint16_t port)
+{
+    uint8_t ret;
+    asm volatile ("inb %1, %0" : "=a" (ret) : "dN" (port));
+    return ret;
+}
+uint16_t inw(uint16_t port)
+{
+    uint16_t ret;
+    asm volatile ("inw %1, %0" : "=a" (ret) : "dN" (port));
+    return ret;
+}
diff --git a/kernel/linker.ld b/kernel/linker.ld
new file mode 100644
index 0000000..9b47325
--- /dev/null
+++ b/kernel/linker.ld
@@ -0,0 +1,44 @@
+/* The bootloader will look at this image and start execution at the symbol
+   designated as the entry point. */
+ENTRY(_start)
+
+/* Tell where the various sections of the object files will be put in the final
+   kernel image. */
+SECTIONS
+{
+        /* Begin putting sections at 1 MiB, a conventional place for kernels to be
+           loaded at by the bootloader. */
+        . = 1M;
+
+        /* First put the multiboot header, as it is required to be put very early
+           early in the image or the bootloader won't recognize the file format.
+           Next we'll put the .text section. */
+        .text BLOCK(4K) : ALIGN(4K)
+        {
+                *(.multiboot)
+                *(.text)
+        }
+
+        /* Read-only data. */
+        .rodata BLOCK(4K) : ALIGN(4K)
+        {
+                *(.rodata)
+        }
+
+        /* Read-write data (initialized) */
+        .data BLOCK(4K) : ALIGN(4K)
+        {
+                *(.data)
+        }
+
+        /* Read-write data (uninitialized) and stack */
+        .bss BLOCK(4K) : ALIGN(4K)
+        {
+                *(COMMON)
+                *(.bss)
+                *(.bootstrap_stack)
+        }
+
+        /* The compiler may produce other sections, by default it will put them in
+           a segment with the same name. Simply add stuff here as needed. */
+}
diff --git a/kernel/main.c b/kernel/main.c
new file mode 100644
index 0000000..219e3ee
--- /dev/null
+++ b/kernel/main.c
@@ -0,0 +1,14 @@
+#include "string.h"
+#include "tty.h"
+#include "vga.h"
+
+void main(void)
+{
+    tty_init();
+    gdt_init();
+    tty_puts("GDT initialized\n");
+    tty_set_color(VGA_MAKE_COLOR(VGA_LIGHT_GRAY, VGA_BLACK));
+    tty_puts("Hello, world!\n");
+    while(1)
+        ;
+}
diff --git a/kernel/panic.c b/kernel/panic.c
new file mode 100644
index 0000000..106141b
--- /dev/null
+++ b/kernel/panic.c
@@ -0,0 +1,2 @@
+#include "panic.h"
+#include "
diff --git a/kernel/ssp.c b/kernel/ssp.c
new file mode 100644
index 0000000..ad47bb4
--- /dev/null
+++ b/kernel/ssp.c
@@ -0,0 +1,19 @@
+#include <stdint.h>
+#include "panic.h"
+
+#if UINT32_MAX == UINTPTR_MAX
+#define STACK_CHK_GUARD 0xdeadbeef
+#else
+#define STACK_CHK_GUARD 0x0ddc0ffeebadf00d
+#endif
+
+uintptr_t __stack_chk_guard = STACK_CHK_GUARD;
+
+__attribute__((noreturn)) void __stack_chk_fail(void)
+{
+#if __STDC_HOSTED__
+    abort();
+#else
+    panic("Stack smashing detected");
+#endif
+}
diff --git a/libc/string.c b/libc/string.c
new file mode 100644
index 0000000..33ccad9
--- /dev/null
+++ b/libc/string.c
@@ -0,0 +1,19 @@
+#include <stdint.h>
+#include "string.h"
+
+int strlen(const char *str)
+{
+    int len = 0;
+    while(s++)
+        len++;
+    return len;
+}
+
+void* memset(void *buf, int val, size_t sz)
+{
+    for(size_t i = 0; i < sz; ++i)
+    {
+        buf[i] = (uint8_t) val;
+    }
+    return buf;
+}
diff --git a/libc/string.h b/libc/string.h
new file mode 100644
index 0000000..8606fab
--- /dev/null
+++ b/libc/string.h
@@ -0,0 +1,3 @@
+#include <stdint.h>
+int strlen(const char*);
+void* memset(void*, int, size_t);