kernel/usermode.c


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#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 TODO: switch to usermode before!
    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); 
    }

    // kernel worker thread on pid1
    if(task_get_current_pid()==1)
    {
	while(1)
	{
	    c1++;
	}
    }
}