syscalls

12 files changed, 301 insertions, 313 deletions

diff --git a/kernel/gdt.c b/kernel/gdt.c
index 4df089f..562fbd5 100644
--- a/kernel/gdt.c
+++ b/kernel/gdt.c
@@ -1,14 +1,28 @@
-#include "kernel/kernel.h"
 // http://wiki.osdev.org/GDT_Tutorial
+#include "kernel/kernel.h"
+#include "kernel/gdt.h"
 
 #include "usermode.h"
 
 #include <stdint.h>
+
 #define GDT_SIZE 6
+static uint8_t gdt_struct[GDT_SIZE*8]; // GLOBAL DESCRIPTOR TABLE
+uint64_t gdt_descriptor;
 
-extern sys_tss;
-static uint8_t gdt_struct[GDT_SIZE*8];
+//https://wiki.osdev.org/Task_State_Segment
+tss_struct sys_tss; //Define the TSS as a global structure
 
+void install_tss(uint32_t esp0){
+
+    // now fill each value
+    // set values necessary
+    sys_tss.ss0 = 0x10;            //kernel data
+    sys_tss.esp0 = esp0;
+
+    // now set the IO bitmap (not necessary, so set above limit)       
+    // sys_tss.iomap = ( unsigned short ) sizeof( tss_struct ); 
+}
 typedef struct GDT_struct
 {
     uint32_t base;
@@ -130,7 +144,7 @@ void gdt_init()
         encodeGdtEntry(&gdt_struct[8*i],myGDT[i]);
 
     // update tss entry
-    install_tss();
+    install_tss(0);
 
-    setup_gdt(&gdt_struct[0],8*GDT_SIZE);
+    asm_setup_gdt(&gdt_struct[0],8*GDT_SIZE);
 }
diff --git a/kernel/gdt.h b/kernel/gdt.h
index 4081a75..a234ea4 100644
--- a/kernel/gdt.h
+++ b/kernel/gdt.h
@@ -1 +1,46 @@
+// https://xarnze.com/posts/post/Tutorial:%20Entering%20User%20mode
+// http://wiki.osdev.org/TSS
+// http://wiki.osdev.org/Global_Descriptor_Table
+
+typedef volatile struct strtss{
+    unsigned short   link;
+    unsigned short   link_h;  
+    unsigned long   esp0;
+    unsigned short   ss0;
+    unsigned short   ss0_h;  
+    unsigned long   esp1;
+    unsigned short   ss1;
+    unsigned short   ss1_h;  
+    unsigned long   esp2;
+    unsigned short   ss2;
+    unsigned short   ss2_h;  
+    unsigned long   cr3;
+    unsigned long   eip;
+    unsigned long   eflags;  
+    unsigned long   eax;
+    unsigned long   ecx; 
+    unsigned long   edx;
+    unsigned long    ebx;  
+    unsigned long   esp;
+    unsigned long   ebp;  
+    unsigned long   esi;
+    unsigned long   edi;  
+    unsigned short   es;
+    unsigned short   es_h;  
+    unsigned short   cs;
+    unsigned short   cs_h;  
+    unsigned short   ss;
+    unsigned short   ss_h;  
+    unsigned short   ds;
+    unsigned short   ds_h;  
+    unsigned short   fs;
+    unsigned short   fs_h;  
+    unsigned short   gs;
+    unsigned short   gs_h;  
+    unsigned short   ldt;
+    unsigned short   ldt_h;  
+    unsigned short   trap;
+    unsigned short   iomap;  
+}__attribute__((packed)) tss_struct;  
+
 void gdt_init();
diff --git a/kernel/interrupts.c b/kernel/interrupts.c
index 04bac9f..cf75798 100644
--- a/kernel/interrupts.c
+++ b/kernel/interrupts.c
@@ -1,14 +1,14 @@
 #include "kernel/kernel.h"
 #include "asm/int.h"
-#include "asm/asm.h"
 #include "asm/pit.h"
 #include "driver/mouse.h"
 #include "interrupts.h"
 #include "asm/x86.h"
 
-#define INT_MAX 255 // size of our interrupts table
+/** The size of our interrupts table  */
+#define INT_MAX 255 
 
-// the interrupt descriptor table
+/** The interrupt descriptor table */
 static struct int_desc
 {
     uint16_t addrLo;
@@ -18,7 +18,7 @@ static struct int_desc
     uint16_t addrHi;
 } idt[INT_MAX];
 
-// interrupt descriptor table descriptor
+/** The interrupt descriptor table descriptor */
 static struct idt_desc
 {
     uint16_t size;
@@ -26,34 +26,63 @@ static struct idt_desc
     uint16_t baseHi;
 } idtd;
 
-uint32_t interrupt_handler(uint32_t esp, uint32_t num)
+/** Sets a handler for a specific interrupt */
+static void int_install_ir(int irq, uint16_t flags, uint16_t sel, void *addr)
 {
-//    if(num!=0)klog("int: %d %d",num,esp);
+   uint64_t base=(uint32_t)&(*(uint32_t*)addr);
 
-    if(num==0)
-    {
-        pit_interrupt_handler();
-	esp=task_switch_next(esp);
-    }
+    idt[irq].addrLo = base & 0xffff;
+    idt[irq].addrHi = (base >> 16) & 0xffff;
+    idt[irq].zeros=0;
+    idt[irq].flags=flags;
+    idt[irq].sel=sel;
+}
+
+/** Installs the interrupt table */
+static void int_install()
+{
+    idtd.size=sizeof(struct int_desc)*INT_MAX;
+    uint32_t addr=(uint32_t)&idt[0];
+    idtd.baseHi=addr>>16;
+    idtd.baseLo=0xffff&addr;
+    __asm__("lidt %0"::"m" (idtd));
+}
 
-    if(num==1)asm_kb_handler();
+/*
+ * Interrupt dispatcher 
+ *
+ * Remeber that we are inside an interrupt here!
+ *
+ */
+
+uint32_t interrupt_handler(uint32_t esp, uint32_t irq)
+{
+    if(irq==0)asm_pit_tick();  
+    if(irq==1)asm_kb_handler();    // TODO: put in ringbuff
+    if(irq==12)asm_mouse_handler();// TODO: put in ringbuff
 
-    if(num==12)asm_mouse_handler();
+    // 0x80 - a syscall is coming in
+    if(irq==128){
 
-    if(num==128){
 	uint32_t *stack=esp;
 	uint32_t eax=stack[11];
 	uint32_t ebx=stack[8];
 	uint32_t ecx=stack[10];
 	uint32_t edx=stack[9];
-	klog("syscall: %d (ebx=0x%08X,ecx=0x%08X,edx=0x%08X)",eax,ebx,ecx,edx);
-	task_wake_syscall_worker();
-	esp=task_syscall(eax,ebx,ecx,edx,esp);
+
+//	klog("syscall: %d (ebx=0x%08X,ecx=0x%08X,edx=0x%08X)",eax,ebx,ecx,edx);
+
+	task_syscall(eax,ebx,ecx,edx);
     }
 
+    if(irq==0 || irq==129 || irq==128)esp=my_scheduler(esp);
+
+    if(irq==255)kpanic("Unhandled Interrupt!");
+
     return esp;
 }
 
+// log helpers //
 void errlog(uint32_t error_code)
 {
     klog("error_code: 0x%08X",error_code);
@@ -66,28 +95,22 @@ void defklog(uint32_t eip, uint16_t cs, uint32_t flags)
     klog("eflags: 0x%08X",flags);
 }
 
-void int_install_ir(int irq, uint16_t flags, uint16_t sel, void *addr);
-
-
-void exception_handle()
+void show_error(uint32_t err)
 {
-   kpanic("exception interrupt");
+   klog("interrupt error code:  0x%08x",err);
+   klog("External Event: %x",err&0b001);
+   klog("Location: %x",err&0b110);
+   klog("Selector: %x",err&0b1111111111111000);
 }
 
+//
+
 void int_default()
 {
    klog("default handler");
    kpanic("unhandled interrupt (is this a panic or should just iognore?)");
 }
 
-void show_error(uint32_t err)
-{
-   klog("interrupt error code:  0x%08x",err);
-   klog("External Event: %x",err&0b001);
-   klog("Location: %x",err&0b110);
-   klog("Selector: %x",err&0b1111111111111000);
-}
-
 void exception_handle_0(){   kpanic("Divide by 0");    }
 void exception_handle_1(){   kpanic("Single step (debugger)");    }
 void exception_handle_2(){   kpanic("Non Maskable Interrupt");    }
@@ -119,8 +142,7 @@ void exception_handle_14(uint32_t error_code,uint32_t eip,uint16_t cs,uint16_t u
    klog("error_code_RSVD: %d",error_code&8?1:0);
    klog("error_code_I/D: %d",error_code&16?1:0);
    klog("at addr: 0x%08X",x86_get_cr(2));
-   
-    defklog(eip,cs,flags);
+   defklog(eip,cs,flags);
    kpanic("Exception: Fault: Page Fault");
 }
 
@@ -129,78 +151,60 @@ void exception_handle_16(){   kpanic("Coprocessor error");    }
 void exception_handle_17(){   kpanic("Alignment Check");    }
 void exception_handle_18(){   kpanic("Machine Check");    }
 
-//set a handler for a specific interrupt
-void int_install_ir(int irq, uint16_t flags, uint16_t sel, void *addr)
-{
-   uint64_t base=(uint32_t)&(*(uint32_t*)addr);
-
-    idt[irq].addrLo = base & 0xffff;
-    idt[irq].addrHi = (base >> 16) & 0xffff;
-    idt[irq].zeros=0;
-    idt[irq].flags=flags;
-    idt[irq].sel=sel;
-}
-
 // set default handler for all interrupts for a start
 void interrupts_init(uint16_t sel)
 {
     //  Setup PIC
     klog("setting up PIC",&idt,&idtd);
-    pic_setup();
+    asm_pic_setup();
 
     klog("initializing. IDT: 0x%08x, IDTD: 0x%08X",&idt,&idtd);
 
+    // Default interrupt handling
     for(int i=0; i<INT_MAX; i++)
     {
-	int_install_ir(i, 0b10001110, sel,&int_default_handler);
+	int_install_ir(i, 0b10001110, sel,&int255);
     }
 
-    // exceptions
-    int_install_ir(0,  0b10001110, 0x08,&int_irq0);
-    int_install_ir(1,  0b10001110, 0x08,&int_irq1);
-    int_install_ir(2,  0b10001110, 0x08,&int_irq2);
-    int_install_ir(3,  0b10001110, 0x08,&int_irq3);
-    int_install_ir(4,  0b10001110, 0x08,&int_irq4);
-    int_install_ir(5,  0b10001110, 0x08,&int_irq5);
-    int_install_ir(6,  0b10001110, 0x08,&int_irq6);
-    int_install_ir(7,  0b10001110, 0x08,&int_irq7);
-    int_install_ir(8,  0b10001110, 0x08,&int_irq8);
-    int_install_ir(9,  0b10001110, 0x08,&int_irq9);
-    int_install_ir(10, 0b10001110, 0x08,&int_irq10);
-    int_install_ir(11, 0b10001110, 0x08,&int_irq11);
-    int_install_ir(12, 0b10001110, 0x08,&int_irq12);
-    int_install_ir(13, 0b10001110, 0x08,&int_irq13);
-    int_install_ir(14, 0b10001110, 0x08,&int_irq14);
-    int_install_ir(15, 0b10001110, 0x08,&int_irq15);
-    int_install_ir(16, 0b10001110, 0x08,&int_irq16);
-    int_install_ir(17, 0b10001110, 0x08,&int_irq17);
-    int_install_ir(18, 0b10001110, 0x08,&int_irq18);
-
-    // setup some custom interrupts
+    // Exceptions
+    int_install_ir(0,  0b10001110, 0x08,&exc0);
+    int_install_ir(1,  0b10001110, 0x08,&exc1);
+    int_install_ir(2,  0b10001110, 0x08,&exc2);
+    int_install_ir(3,  0b10001110, 0x08,&exc3);
+    int_install_ir(4,  0b10001110, 0x08,&exc4);
+    int_install_ir(5,  0b10001110, 0x08,&exc5);
+    int_install_ir(6,  0b10001110, 0x08,&exc6);
+    int_install_ir(7,  0b10001110, 0x08,&exc7);
+    int_install_ir(8,  0b10001110, 0x08,&exc8);
+    int_install_ir(9,  0b10001110, 0x08,&exc9);
+    int_install_ir(10, 0b10001110, 0x08,&exc10);
+    int_install_ir(11, 0b10001110, 0x08,&exc11);
+    int_install_ir(12, 0b10001110, 0x08,&exc12);
+    int_install_ir(13, 0b10001110, 0x08,&exc13);
+    int_install_ir(14, 0b10001110, 0x08,&exc14);
+    int_install_ir(15, 0b10001110, 0x08,&exc15);
+    int_install_ir(16, 0b10001110, 0x08,&exc16);
+    int_install_ir(17, 0b10001110, 0x08,&exc17);
+    int_install_ir(18, 0b10001110, 0x08,&exc18);
+    
+
+    // Custom interrupts (hardcoded)
     // remember that we shifted all interrupts with the pic by 32
 
-    // install PIT interrupt handler (irq 0 => 32)
+    // PIT interrupt handler (irq 0 => 32)
     int_install_ir(32,   0b10001110, 0x08,&int0);
 
-    // install keyboard interrupt handler (irq 1 => 33)
+    // Keyboard interrupt handler (irq 1 => 33)
     int_install_ir(33,   0b10001110, 0x08,&int1);
 
-    //mouse  interrupt handler (irq 12 => 34)
+    // Mouse  interrupt handler (irq 12 => 34)
     int_install_ir(44,   0b10001110, 0x08,&int12);
 
-    //our system calls (can be called from ring3 (0b11))
+    // System Calls / they can be called from ring3 (0b11)
     int_install_ir(0x80, 0b11101110, 0x08,&int128);
+    // Wake Scheduler
+    int_install_ir(0x81, 0b11101110, 0x08,&int129);
 
+    // install IVT
     int_install();
 }
-
-void int_install()
-{
-    idtd.size=sizeof(struct int_desc)*INT_MAX;
-
-    uint32_t addr=(uint32_t)&idt[0];
-    idtd.baseHi=addr>>16;
-    idtd.baseLo=0xffff&addr;
-
-    __asm__("lidt %0"::"m" (idtd));
-}
diff --git a/kernel/kernel.c b/kernel/kernel.c
index 4406ea0..43c986c 100644
--- a/kernel/kernel.c
+++ b/kernel/kernel.c
@@ -59,7 +59,7 @@ void kernel_main(uint32_t eax,uint32_t ebx)
     // https://wiki.osdev.org/Symmetric_Multiprocessing
     klog("Symmetric Multi Processing (SMP) start ... ");
     smp_log_procdata(&procdata);
-    //smp_start_aps(&procdata);
+    smp_start_aps(&procdata);
     
     klog("Vritual Memory / Paging init ... ");
     pdirectory *dir=vmem_init(kernel_blocks,(uint32_t)info->framebuffer_addr);
diff --git a/kernel/kernel.h b/kernel/kernel.h
index 1949af5..c214c4a 100644
--- a/kernel/kernel.h
+++ b/kernel/kernel.h
@@ -11,7 +11,7 @@
 #define FIFO_MAX_RINGBUFFERS 20
 #define MAX_FIFOS 20
 #define MAX_FD 20
-#define MAX_TASKS 255
+#define MAX_TASKS 10
 #define MEM_PRINT_MEMORYMAP
 
 //#define LOG_SYSCALLS 
@@ -19,7 +19,13 @@
 #define KMALLOC_MEM_SIZE  1024*1024*8  // 8MB for in kernel-memory
 #define NUMBER_SPINLOCKS 16
 
+#define S1(x) #x
+#define S2(x) S1(x)
+
+// __FUNCTION__ ?
 #define kpanic(...) {log(__FILE__,0," \033[41;37m--PANIC--\033[37;40m " __VA_ARGS__ ); while(1);}
-#define klog(...) log(__FILE__,10,  __VA_ARGS__)
+#define klog(...) log(__FILE__ ":" S2(__LINE__), 10,  __VA_ARGS__)
+
+//#define klog(...) __asm__("nop")
 
 #endif
diff --git a/kernel/scheduler.c b/kernel/scheduler.c
index b367825..ee1cea2 100644
--- a/kernel/scheduler.c
+++ b/kernel/scheduler.c
@@ -1,7 +1,3 @@
-// http://hosted.cjmovie.net/TutMultitask.htm
-//
-//
-
 #include "kernel.h"
 #include "mem.h"
 #include "asm/x86.h"
@@ -11,53 +7,70 @@
 #include "fs/fs.h"
 #include "fs/ext2.h"
 
-static volatile int volatile current_task=-1;
+#define NO_TASK 0xffffffff
+
+static volatile uint32_t current_task=NO_TASK;
 
 static volatile struct task_list_struct
 {
-    volatile int parent;
-    volatile bool active;
-    volatile uint32_t esp; // stack pointer of the task;
-    volatile pdirectory *vmem; // number of virtual memory table to switch to
-    volatile bool waiting; 
-    volatile bool skipwait;
-    volatile uint32_t brk;
-    volatile uint32_t esp0;
-
-    volatile bool syscall; // waiting for syscall to be processed.
+    volatile bool active;      // is this slot used (Y/N)
+    volatile uint32_t pid;     // process id (TODO)
+
+    volatile uint32_t parent;  // parent process id
+    volatile uint32_t esp;     // stack pointer of the task
+    volatile uint32_t esp0;    // tss.esp0
+    volatile pdirectory *vmem; // number of virtual memory table
+
+    volatile uint32_t brk;     // memory brk pos
+
+    volatile bool    wait; // waiting for syscall to be processed.
     volatile uint32_t eax;
     volatile uint32_t ebx;
     volatile uint32_t ecx;
     volatile uint32_t edx;
-
     
 }volatile task_list[MAX_TASKS];
 
-volatile int add_task(uint32_t esp, uint32_t vmem)
+volatile int task_reset(uint32_t pid, uint32_t entry, uint32_t stack)
+{
+    uint32_t *stk=task_list[pid].esp;
+    stk[14]=entry;
+    stk[17]=stack;
+}
+
+volatile int add_task(uint32_t parent)
 {
     for(int i=0;i<MAX_TASKS;i++)
     {
 	if(task_list[i].active!=true)
 	{
-	    task_list[i].parent=current_task;
-	    task_list[i].vmem=vmem;
-	    task_list[i].esp  = kballoc(4)+4*4096;
+	    task_list[i].parent=parent;
+
+	    // TODO: do this without paging please!
+	    task_list[i].vmem=vmem_new_space_dir(task_list[parent].vmem); //TODO: what will happen if we get rescheduled!?!?!
+	    task_list[i].esp = kballoc(4)+2*4096; // center
+
+	    // TODO: use own page here and copy it instead of this!
             task_list[i].esp0 = kballoc(4)+4*4096;
-	    task_list[i].active=true;
-	    task_list[i].waiting=false;
-	    task_list[i].skipwait=false;
+
+	    task_list[i].wait=false;
 	    task_list[i].brk=task_list[current_task].brk;
 
-            uint32_t *addi2=(uint32_t *)esp;
-	    addi2+=14;
+            uint32_t *source=(uint32_t *)task_list[parent].esp;
+	    uint32_t *dst=(uint32_t *)task_list[i].esp;
 
-	    for(int x=0;x<15;x++)
+	    for(int x=0;x<100;x++) //TODO:  better copy this page too instead of stack
 	    {
-		task_list[i].esp-=4;
-		uint32_t *addi1=(uint32_t *)task_list[i].esp;
-		*addi1=*addi2;
-		addi2--;
+		*dst=*source;
+		dst++;
+		source++;
 	    }
+
+	    uint32_t *stack=task_list[i].esp;
+	    stack[12]=0x1; 
+	    stack[13]=0; // this task returns pid=0 to the caller
+
+	    task_list[i].active=true; //TODO: LOCK! (also other similar)
 	    return i;
 	}
     }
@@ -65,34 +78,44 @@ volatile int add_task(uint32_t esp, uint32_t vmem)
     kpanic("out of task slots!");
 }
 
-void task_wake_syscall_worker()
-{
-    task_list[2].waiting=false; // todo: context switch immiditly?
-}
+
+/**
+ * kernel space worker thread
+ *
+ * we can get interrupted by an interrupt ANYTIME!
+ *
+ */
 
 void task_syscall_worker()
 {
-    klog("checking if any pending syscalls.");
-
-    for(int i=0;i<MAX_TASKS;i++)
+    while(1)
     {
-	if(task_list[i].syscall)
-	{
-	    klog("task %d waiting on syscall %d. processing...",i,task_list[i].eax);
+	//klog("checking if any pending syscalls.");
 
-	    task_list[2].vmem=task_list[i].vmem; // switch syscall worker to pagedir of calling userprog
-	    x86_set_page_directory(task_list[2].vmem);
-	    syscall_generic(task_list[i].eax,
-			task_list[i].ebx,
-			task_list[i].ecx,
-			task_list[i].edx);
-
-	    task_list[i].syscall=false;
+	for(int i=0;i<MAX_TASKS;i++)
+	{
+	    if(task_list[i].wait)
+	    {
+    //	    klog("task %d waiting on syscall %d. processing...",i,task_list[i].eax);
+		task_list[2].vmem=task_list[i].vmem; // switch syscall worker to pagedir of calling userprog
+		x86_set_page_directory(task_list[2].vmem);
+		uint32_t ret= syscall_generic(task_list[i].eax,
+			    task_list[i].edx,
+			    task_list[i].ecx,
+			    task_list[i].ebx,
+			    i);
+
+		uint32_t *stack=task_list[i].esp;
+		stack[12]=0x1; 
+		stack[13]=ret; 
+	    
+		task_list[i].wait=false;
+	    }
 	}
-    }
 
-    task_list[current_task].waiting=true;
-    __asm__("hlt"); //TODO: force task switch here... via syscall?
+	task_list[2].wait=true;
+	__asm__("int $0x81"); // wake scheduler!
+    }
 }
 
 //
@@ -105,24 +128,22 @@ void task_syscall_worker()
 //
 // we need to return a NEW stack pointer where popa will get the registers the new task requires
 //
-static int first=1;
 volatile uint32_t my_scheduler(uint32_t oldesp)
 {
-
-    if(!first)
-    {
-	task_list[current_task].esp=oldesp;
-    }
-	first=0;
+    // 
+    static bool first=true;
+    if(current_task==NO_TASK)return oldesp;
+    if(!first) task_list[current_task].esp=oldesp;
+    first=false;
+    //
 
     for(int i=0;i<MAX_TASKS;i++)
     {
 	int pid=(current_task+1+i)%MAX_TASKS; // schedule round robin style
 
-	if(task_list[pid].active && !task_list[pid].waiting && !task_list[pid].syscall)
+	if(task_list[pid].active && !task_list[pid].wait) // find active non-blocked task
 	{
-	    if(current_task!=pid)
-		    klog("switch from %d to %d", current_task, pid);
+	    //if(current_task!=pid)klog("switch from %d to %d", current_task, pid);
 
 	    current_task=pid;
 	    install_tss(task_list[pid].esp0);
@@ -136,28 +157,22 @@ volatile uint32_t my_scheduler(uint32_t oldesp)
     kpanic("nothing to schedule!");
 }
 
-// this gets called by our clock interrupt regularly!
-volatile uint32_t task_switch_next(uint32_t oldesp)
+volatile uint32_t task_syscall(uint32_t eax,uint32_t ebx, uint32_t ecx, uint32_t edx)
 {
-    // check if multitasking has been started
-    if(current_task<0)return oldesp; 
-    return my_scheduler(oldesp);
-}
-
-volatile uint32_t task_syscall(uint32_t eax,uint32_t ebx, uint32_t ecx, uint32_t edx,uint32_t oldesp)
-{
-    task_list[current_task].syscall=true;
+    task_list[current_task].wait=true;
     task_list[current_task].eax=eax;
     task_list[current_task].ebx=ebx;
     task_list[current_task].ecx=ecx;
     task_list[current_task].edx=edx;
-    return my_scheduler(oldesp);
+
+    task_list[2].wait=false;
 }
 
 //TODO: free vmem too!
 //TODO: notify waiting parent when child finished;
 volatile uint32_t task_exit(uint32_t oldesp)
 { 
+    /*
 
     task_list[current_task].active=false;
     int parent_pid=task_list[current_task].parent;
@@ -174,8 +189,8 @@ volatile uint32_t task_exit(uint32_t oldesp)
 	}
 	else
 	{
-	   klog("[%d] skipwait", parent_pid);
-	   task_list[parent_pid].skipwait=true;
+//	   klog("[%d] skipwait", parent_pid);
+//	   task_list[parent_pid].skipwait=true;
 	}
 	
     }
@@ -183,11 +198,12 @@ volatile uint32_t task_exit(uint32_t oldesp)
     vmem_free_dir(task_list[current_task].vmem);
 
     return my_scheduler(oldesp);
+    */
 
 }
 
 volatile uint32_t task_wait(uint32_t oldesp)
-{ 
+{ /*
     klog("[%d] wait", current_task);
     if(task_list[current_task].skipwait)
     {
@@ -198,13 +214,14 @@ volatile uint32_t task_wait(uint32_t oldesp)
 	task_list[current_task].waiting=true;
     }
     return my_scheduler(oldesp);
+    */
 }
 
-volatile uint32_t task_fork(uint32_t oldesp)
+volatile uint32_t task_fork(uint32_t pid)
 { 
-   int pid=add_task(oldesp,vmem_new_space_dir(task_list[current_task].vmem));
+   int ret=add_task(pid);
    klog("[%d] forked -> [%d] (free blocks remaining: %d )", current_task, pid,mem_get_free_blocks_count());
-   return pid;
+   return ret;
 }
 
 // init task (root of all other tasks / processes) //
@@ -220,27 +237,28 @@ volatile void scheduler_init(pdirectory *dir)
     // this is our main user task on slot 0 
     task_list[0].parent=0;
     task_list[0].active=true;
-    task_list[0].waiting=false;
+    task_list[0].wait=false;
     task_list[0].vmem=dir;
-    task_list[0].esp = kballoc(4)+4*4096;
+    task_list[0].esp = kballoc(4)+3*4096;
     task_list[0].esp0 = kballoc(4)+4*4096;
 
-    task_list[1].parent=0;
-    task_list[1].active=true;
-    task_list[1].waiting=false;
-    task_list[1].vmem=dir;
-    task_list[1].esp = kballoc(4)+4*4096; 
-    task_list[1].esp0 = 0; // not needed by kernel space tasks
+//    task_list[1].parent=0;
+//    task_list[1].active=true;
+//    task_list[1].waiting=false;
+//    task_list[1].syscall=false;
+//    task_list[1].vmem=dir;
+//    task_list[1].esp = kballoc(4)+3*4096; 
+//    task_list[1].esp0 = 0; // not needed by kernel space tasks
 
     task_list[2].parent=0;
     task_list[2].active=true;
-    task_list[2].waiting=false;
+    task_list[2].wait=false;
     task_list[2].vmem=dir;
-    task_list[2].esp = kballoc(4)+4*4096; 
+    task_list[2].esp = kballoc(4)+3*4096; 
     task_list[2].esp0 = 0; // not needed by kernel space tasks
 
     task_pusha(task_list[2].esp);
-    task_pusha(task_list[1].esp);
+//    task_pusha(task_list[1].esp);
     task_pusha(task_list[0].esp);
 
     // finally enable interrrupts so the scheduler is called (by timer)
diff --git a/kernel/scheduler.h b/kernel/scheduler.h
index db0e3ae..7a5bea3 100644
--- a/kernel/scheduler.h
+++ b/kernel/scheduler.h
@@ -1 +1,2 @@
+// http://hosted.cjmovie.net/TutMultitask.htm
 void scheduler_init(void *pdirectory_dir);
diff --git a/kernel/smashing.c b/kernel/smashing.c
index 005e784..dc092be 100644
--- a/kernel/smashing.c
+++ b/kernel/smashing.c
@@ -9,8 +9,6 @@
 #else
 #define STACK_CHK_GUARD 0x595e9fbd94fda766
 #endif
- 
-
 
 uintptr_t __stack_chk_guard = STACK_CHK_GUARD;
  
diff --git a/kernel/syscalls.c b/kernel/syscalls.c
index 56c4ae8..7a0dc50 100644
--- a/kernel/syscalls.c
+++ b/kernel/syscalls.c
@@ -22,6 +22,8 @@ static uint32_t next_fd=0;
 static fifo fifos[MAX_FIFOS];
 static uint32_t next_fifo=0;
 
+extern uint32_t fb_addr;
+
 // screen / terminal
 term_out screen;
 terminal_tty tty1;
@@ -54,9 +56,6 @@ int syscall_gettimeofday(struct timeval *tv, struct timezone *tz)
 
 int syscall_lseek(int file,int ptr,int dir) 
 {
-    #ifdef LOG_SYSCALLS
-    klog("lseek (file=%d, ptr=%d, dir=%d)", file,ptr,dir);
-    #endif
 
     kpanic("unhandled syscall: lseek");
 
@@ -66,9 +65,6 @@ int syscall_lseek(int file,int ptr,int dir)
 // TODO: /dev/console or /dev/tty1 - /dev/ttyN
 int syscall_write(int file, char *buf, int len)
 {
-    #ifdef LOG_SYSCALLS
-    klog("[%d] write(file=%d, buf=0x%08X, len=%d)", task_get_current_pid(),file,buf,len);
-    #endif
 
     for(int i=0;i<len;i++)
     {
@@ -80,9 +76,6 @@ int syscall_write(int file, char *buf, int len)
 
 int syscall_read(int file, char *buf, int len)
 {
-    #ifdef LOG_SYSCALLS
-    klog("read(file=%d, buf=0x%08X, len=%d)", file,buf,len);
-    #endif
     //file 0 = stdin ,  file 1 = stdout , file 2 = stderr
 
     char c;
@@ -105,9 +98,6 @@ int syscall_read(int file, char *buf, int len)
 //TODO: replace with dirent!
 int syscall_readdir(const char *name,fs_dirent *dirs,int max)
 {
-    #ifdef LOG_SYSCALLS
-    klog("readdir(name=0x%08X, dirs=0x%08X,  %d)", name,dirs,max);
-    #endif
 
     return fs_readdir(name,dirs,max);
 }
@@ -116,9 +106,6 @@ int syscall_readdir(const char *name,fs_dirent *dirs,int max)
 int syscall_poll(int file)
 {
     file=2; //workaround
-    #ifdef LOG_SYSCALLS
-    klog("has data waiting?");
-    #endif
 
     return fd_has(&fds[file]);
 }
@@ -126,9 +113,6 @@ int syscall_poll(int file)
 // TODO: DELETE THIS SHIT!
 int syscall_tune(int v1,int v2, int v3)
 {
-    #ifdef LOG_SYSCALLS
-    klog("tuning request");
-    #endif
 
     // osbolete
     /*
@@ -176,29 +160,28 @@ int copy_args(char **in, char **out)
     return count;
 }
 
-int syscall_execve(char *name, char **argv, char **env)
+int syscall_execve(char *name, char **argv, char **env,int pid)
 {
-    #ifdef LOG_SYSCALLS
-    klog("execve (name=0x%08X(%s), argvs=0x%08X,  env=0x%08X)", name,name,argv,env);
-    #endif
-
+    
     int arg_count=0;
     while(argv[arg_count]!=NULL)arg_count++;
 
-    char **argv1=kballoc(1);
+    char **argv1=0x08000000;
     if(argv!=NULL)
     {
         copy_args(argv,argv1);
     }
+
     else{
 	argv1=NULL;
     }
 
-    char **env1=kballoc(1);
+    char **env1=0x08020000;
     if(env!=NULL)
     {
 	copy_args(env,env1);
     }
+
     else{
 	env1=NULL;
     }
@@ -209,17 +192,18 @@ int syscall_execve(char *name, char **argv, char **env)
 
     if(!entry_global)
     {
-	#ifdef LOG_SYSCALLS
-	klog("execve: bailing out!");
-	#endif
+	kpanic("error loading %s",name);
 	return -1; // errror loading
     }
 
+    task_reset(pid,entry_global,0x08fff000);
+    return 0;
+
     /* try to move this to asm */
     //    asm volatile("jmp ."); // loop forever
     //klog("returning to jump addy (0x%08X)", entry_global);
-
-    asm volatile("mov $0x8fff000,%esp"); // set stack at high end of process image
+/*
+    asm volatile("mov $0x08fff000,%esp"); // set stack at high end of process image
 
     asm volatile ("push %0" :: "r" (argv1));
     asm volatile ("push %0" :: "r" (arg_count));
@@ -231,6 +215,7 @@ int syscall_execve(char *name, char **argv, char **env)
 
     asm volatile ("sti");
     asm volatile ("ret");
+    */
 
     // this is never reached!
 }
@@ -245,9 +230,6 @@ int get_max_fd()
 // TODO: allow opening existing files/named pipes
 int syscall_open(char *name, int flags, int mode)
 {
-    #ifdef LOG_SYSCALLS
-    klog("open (name=0x%08X(\"%s\"), flags=%d,  mode=%d)",name, name,flags,mode);
-    #endif
     
     if( next_fifo>=MAX_FIFOS || next_fd>=MAX_FD)kpanic("we ran out of fd's or fifo's");
     
@@ -258,13 +240,20 @@ int syscall_open(char *name, int flags, int mode)
     }
     else
     {
-	// FIRST TIME WE SEE THE GENIUS OF OUR ABSTRACTIONS (I HOPE...)
+
+	// HERE WE SEE THE GENIUS OF OUR ABSTRACTIONS (I HOPE...)
+	
+	if (fb_addr<0x100000)
+	{
 	screen.put_char=console_put_char;
 	screen.update_cursor=update_cursor;
-
-	// FIRST TIME WE SEE THE GENIUS OF OUR ABSTRACTIONS (I HOPE...)
+	}
+	else
+	{
 	screen.put_char=vesa_console_put_char;
 	screen.update_cursor=vesa_update_cursor;
+	}
+
 
 	tty1=terminal_init(&screen,NULL);
 
@@ -284,9 +273,6 @@ int syscall_open(char *name, int flags, int mode)
 //
 int syscall_close(int file,int none1,int none2)  
 {
-    #ifdef LOG_SYSCALLS
-    klog("close (file=%d)", file);
-    #endif
 
     //if(file!=0&&file!=1&&file!=2)
     //    kpanic("unhandled syscall: close");
@@ -297,9 +283,6 @@ int syscall_close(int file,int none1,int none2)
 // TODO: check if file is termminal!
 int syscall_isatty(int file,int none1,int none2)  
 {
-    #ifdef LOG_SYSCALLS
-    klog("isatty (file=%d)", file);
-    #endif
 
     return 1;
 }
@@ -315,9 +298,6 @@ uint32_t syscall_sbrk(int incr, int none1, int none2)
 
     task_set_brk(alloc);
 
-    #ifdef LOG_SYSCALLS
-    klog("sbrk (incr=%d) = 0x%08X", incr,oldalloc);
-    #endif
 
     return oldalloc;
 }
@@ -325,10 +305,6 @@ uint32_t syscall_sbrk(int incr, int none1, int none2)
 // stat, fstat, lstat
 int syscall_stat(const char *path, struct stat *st,int none)
 {
-    #ifdef LOG_SYSCALLS
-    klog("stat (path=0x%08X,stat=0x%08X)", path,st);
-    #endif
-
     st->st_mode = S_IFCHR;
     return 0;
 }
@@ -336,7 +312,7 @@ int syscall_stat(const char *path, struct stat *st,int none)
 /// there also is task_fork, task_wait, task_exit.. which is in scheduler.c
 ////////////////////////////////////////
 
-uint32_t syscall_generic(uint32_t nr,uint32_t p1, uint32_t p2, uint32_t p3)
+uint32_t syscall_generic(uint32_t nr,uint32_t p1, uint32_t p2, uint32_t p3, uint32_t pid)
 {
 
     switch(nr){
@@ -345,9 +321,9 @@ uint32_t syscall_generic(uint32_t nr,uint32_t p1, uint32_t p2, uint32_t p3)
     case  SYSCALL_CLOSE       :
 	return syscall_close(p1,p2,p3);
     case  SYSCALL_EXECVE      :
-	return syscall_execve(p1,p2,p3);
+	return syscall_execve(p1,p2,p3,pid);
     case  SYSCALL_FORK        :
-	return task_fork(p1,p2,p3);
+	return task_fork(pid);
     case  SYSCALL_GETPID      :
 //	return syscall_getpid(p1,p2,p3);
 	return -1;
diff --git a/kernel/usermode.c b/kernel/usermode.c
index 3befefd..7153e29 100644
--- a/kernel/usermode.c
+++ b/kernel/usermode.c
@@ -1,53 +1,26 @@
-
 #include "usermode.h"
 
 #include "syscalls.h"
 #include "kmalloc.h"
 
-#include "asm/syscall.h"
 #include "asm/usermode.h"
 #include "kernel.h"
 
 #include <stddef.h>
 
-//https://wiki.osdev.org/Task_State_Segment
-tss_struct sys_tss; //Define the TSS as a global structure
-
-static volatile uint32_t c1;
-static volatile uint32_t c2;
-
-void install_tss(uint32_t esp0){
-
-    // now fill each value
-    // set values necessary
-    sys_tss.ss0 = 0x10;            //kernel data
-    sys_tss.esp0 = esp0;
-
-    // now set the IO bitmap (not necessary, so set above limit)       
-    // sys_tss.iomap = ( unsigned short ) sizeof( tss_struct ); 
-}
-
-void initfunc()
-{
-    while(1)
-    {
-	c2++;
-    }
-}
-
 void userfunc()
 {
 
     // we need enable here again (since the pushed eflags have it disabled)!
     x86_sti(); 
 
-    // if we are pid 0, replace ourselves with /bin/init and enter via usermode
+    // if we are pid 0, replace ourselves with /bin/init and enter usermode
     if(task_get_current_pid()==0)
     {
 	    uint32_t alloc;
 	    uint32_t entry_global=load_elf(BIN_INIT,&alloc);
 	    task_set_brk(alloc);
-	    usermode(entry_global); 
+	    asm_usermode(entry_global); 
     }
 
     // kernel worker thread: SLEEPER
@@ -62,10 +35,7 @@ void userfunc()
     // kernel worker thread: SYSCALL CHECKER
     if(task_get_current_pid()==2)
     {
-	while(1)
-	{
-	    task_syscall_worker();
-	}
+        task_syscall_worker();
     }
 }
 
diff --git a/kernel/usermode.h b/kernel/usermode.h
index fafad5b..e69de29 100644
--- a/kernel/usermode.h
+++ b/kernel/usermode.h
@@ -1,45 +0,0 @@
-// https://xarnze.com/posts/post/Tutorial:%20Entering%20User%20mode
-// http://wiki.osdev.org/TSS
-// http://wiki.osdev.org/Global_Descriptor_Table
-
-typedef volatile struct strtss{
-    unsigned short   link;
-    unsigned short   link_h;  
-    unsigned long   esp0;
-    unsigned short   ss0;
-    unsigned short   ss0_h;  
-    unsigned long   esp1;
-    unsigned short   ss1;
-    unsigned short   ss1_h;  
-    unsigned long   esp2;
-    unsigned short   ss2;
-    unsigned short   ss2_h;  
-    unsigned long   cr3;
-    unsigned long   eip;
-    unsigned long   eflags;  
-    unsigned long   eax;
-    unsigned long   ecx; 
-    unsigned long   edx;
-    unsigned long    ebx;  
-    unsigned long   esp;
-    unsigned long   ebp;  
-    unsigned long   esi;
-    unsigned long   edi;  
-    unsigned short   es;
-    unsigned short   es_h;  
-    unsigned short   cs;
-    unsigned short   cs_h;  
-    unsigned short   ss;
-    unsigned short   ss_h;  
-    unsigned short   ds;
-    unsigned short   ds_h;  
-    unsigned short   fs;
-    unsigned short   fs_h;  
-    unsigned short   gs;
-    unsigned short   gs_h;  
-    unsigned short   ldt;
-    unsigned short   ldt_h;  
-    unsigned short   trap;
-    unsigned short   iomap;  
-}__attribute__((packed)) tss_struct;  
-
diff --git a/kernel/vmem.c b/kernel/vmem.c
index 5bf530f..d026e9e 100644
--- a/kernel/vmem.c
+++ b/kernel/vmem.c
@@ -8,7 +8,7 @@
 #include "vmem.h"
 
 static uint32_t kernel_pages;
-static uint32_t fb_addr;
+uint32_t fb_addr;
 
 // TODO : why is the frame not 0xfffff??
 enum PAGE_PTE_FLAGS 
@@ -299,6 +299,7 @@ pdirectory* vmem_new_space_dir(pdirectory *copy_dir)
     phys_addr=fb_addr;
     virt_addr=fb_addr;
 
+    if(fb_addr>0x100000)
     for(int j=0;j<4;j++)
     {