The task switching is inconsistent

arch/i686/bootstrap.s

@@ -28,7 +28,7 @@ undefined behavior.
 .section .bss, "aw", @nobits
 .align 16
 stack_bottom:
-.skip 16384 # 16 KiB
+.skip (1 << 16) # 16 KiB
 stack_top:
 
 .global boot_page_directory

arch/i686/interrupts/interrupt.c

@@ -56,7 +56,7 @@ __attribute__((interrupt)) void exception(struct interrupt_frame*)
     while (1) { }
 }
 
-__attribute__((interrupt)) void page_fault(struct interrupt_frame*)
+__attribute__((interrupt)) void page_fault(struct interrupt_frame* frame)
 {
     asm("cli");
     terminal_writestring("Page Fault\n");

arch/i686/interrupts/irq0.s

@@ -33,12 +33,11 @@ mov %ax, %es
 mov %ax, %fs
 mov %ax, %gs
 
+pop %eax
 popa
 
 mov (esp), %esp
 
-push (ss)
-push (esp)
 push (eflags)
 push (cs)
 push (eip)
@@ -55,6 +54,7 @@ mov %ax, %es
 mov %ax, %fs
 mov %ax, %gs
 
+pop %eax
 popa
 
 push (ss)

arch/i686/interrupts/syscall.s

@@ -1,4 +1,12 @@
 .extern _syscall
+
+.section .bss, "aw", @nobits
+.align 16
+syscall_stack_bottom:
+.skip (1 << 16) # 16 KiB
+syscall_stack_top:
+
+.section .text
 .global syscall
 syscall:
 mov $0x10, %edx
@@ -8,7 +16,8 @@ mov %ax, %fs
 mov %ax, %gs
 
 mov %esp, %edx
-mov $0x00f00000, %esp
+
+mov $syscall_stack_top, %esp
 push 0x10(%edx)
 push 0x0C(%edx)
 push 0x08(%edx)

arch/i686/paging.c

@@ -58,6 +58,7 @@ static void set_page_directory_entry(uintptr_t address, struct x86_Page_Table* t
     boot_page_directory[address >> 22].address = ((uintptr_t)(table) - 0xC0000000) >> 12;
     boot_page_directory[address >> 22].present = true;
     boot_page_directory[address >> 22].read_write = true;
+    boot_page_directory[address >> 22].user_supervisor = true;
 }
 
 
@@ -92,5 +93,7 @@ void setup_paging() {
     user_data_table.read_write = true;
     user_data_table.user_supervisor = true;
 
+    user_data[0] = 'B';
+
     reload_pages();
 }

arch/i686/tty.c

@@ -88,6 +88,7 @@ static uint16_t terminal_getentryat(size_t x, size_t y)
 
 static void terminal_scroll() 
 {
+    /*
     for (size_t y = 0; y < VGA_HEIGHT; y++) {
         for (size_t x = 0; x < VGA_WIDTH; x++) {
             if (y == VGA_HEIGHT - 1) {
@@ -99,7 +100,11 @@ static void terminal_scroll()
             terminal_putentryat(scrolled, color, x, y);
         }
     }
-    terminal_row = VGA_HEIGHT - 1;
+    */
+
+    terminal_initialize();
+
+    terminal_row = 0;
     terminal_column = 0;
 }
 

kernel/elf.c

@@ -18,7 +18,7 @@ extern void jump_to_userspace();
 
 void run_program(uint8_t* code, size_t code_length, uint8_t* data, size_t data_length)
 {
-    uint8_t* userland_code = (uint8_t*) 0x00000000;
+    uint8_t* userland_code = (uint8_t*) 0x00000010;
     uint8_t* userland_data = (uint8_t*) 0x00400000;
 
     memcpy(userland_code, code, code_length);
@@ -26,7 +26,7 @@ void run_program(uint8_t* code, size_t code_length, uint8_t* data, size_t data_l
 
     struct CPUState target = {
         .eip = (size_t) userland_code,
-        .esp = 0x00400000,
+        .esp = 0x00401000,
         .eax = 0,
         .ebx = 0,
         .ecx = 0,
@@ -34,7 +34,7 @@ void run_program(uint8_t* code, size_t code_length, uint8_t* data, size_t data_l
         .cs = 0x18 | 0x3,
         .ds = 0x20 | 0x3,
         .eflags = 0x0200,
-        .ebp = 0x00c00f00,
+        .ebp = 0,
     };
 
     struct Task task = {

kernel/kernel.c

@@ -14,11 +14,15 @@
 #endif
 
 uint8_t program[] = {
-    0xcd, 0x80, // int 0x80
+    // 0xcd, 0x80, // int $0x80
+    0xb9, 0x02, 0x00, 0x00, 0x00, // mov $0, %ecx
+    0xff, 0xe1, // jmp *%ecx
 };
 
-uint8_t data[] = "Hello From Userspace\n";
+// uint8_t data[] = "Hello From Userspace\n";
+uint8_t data[] = {};
 
+void irq0();
 
 void kernel_main(void) 
 {
@@ -38,9 +42,10 @@ void kernel_main(void)
     run_program(program, sizeof(program), data, sizeof(data));
 
     asm("sti");
+    asm("int $0x20");
 
     while (true) {
         terminal_writestring("Hello from Kernelspace 1\n");
-        terminal_writestring("Hello from Kernelspace 2\n");
+        // terminal_writestring("Hello from Kernelspace 2\n");
     }
 }

kernel/syscall.c

@@ -35,5 +35,5 @@ void _syscall(uint32_t a, uint32_t b, uint32_t c)
             break;
     }
     */
-    terminal_writestring("waow :3");
+    terminal_writestring("waow :3\n");
 }

kernel/task.c

@@ -118,6 +118,7 @@ void next_task() {
     eip = s.eip;
 
     if ((cs & 3) == 0) {
+        // esp -= 4;
         jump_kernel(
             s.edi, 
             s.esi,