syscalls.c

Go to the documentation of this file.

/*
 *                               POK header
 * 
 * The following file is a part of the POK project. Any modification should
 * made according to the POK licence. You CANNOT use this file or a part of
 * this file is this part of a file for your own project
 *
 * For more information on the POK licence, please see our LICENCE FILE
 *
 * Please follow the coding guidelines described in doc/CODING_GUIDELINES
 *
 *                                      Copyright (c) 2007-2009 POK team 
 *
 * Created by julien on Thu Jan 15 23:34:13 2009 
 */

#include <errno.h>
#include <core/debug.h>
#include <core/partition.h>
#include <core/syscall.h>

#include "gdt.h"
#include "event.h"

#define PARTITION_ID(cs) (((cs >> 3) - 4) / 2)

INTERRUPT_HANDLER_syscall(syscall_gate)
{
   pok_syscall_info_t   syscall_info;
   pok_ret_t            syscall_ret;
   pok_syscall_args_t*  syscall_args;
   pok_syscall_id_t     syscall_id;

   /*
    * Give informations about syscalls: which partition, thread
    * initiates the syscall, the base addr of the partition and so on.
    */
   syscall_info.partition = PARTITION_ID (frame->cs);
   syscall_info.base_addr = pok_partitions[syscall_info.partition].base_addr;
   syscall_info.thread    = POK_SCHED_CURRENT_THREAD;

   syscall_args = (pok_syscall_args_t*) (frame->ebx + syscall_info.base_addr);

   /*
    * Get the syscall id in the eax register
    */
   syscall_id = (pok_syscall_id_t) frame->eax;

   /*
    * Check that pointer is inside the adress space
    */
   if (POK_CHECK_PTR_IN_PARTITION(syscall_info.partition, syscall_args) == 0)
   {
         syscall_ret = POK_ERRNO_EINVAL;
   }
   else
   {
      /*
       * Perform the syscall baby !
       */
      syscall_ret = pok_core_syscall (syscall_id, syscall_args, &syscall_info);
   }

   /*
    * And finally, put the return value in eax register
    */
   asm ("movl %0, %%eax  \n"
        :
        : "m" (syscall_ret));
}

pok_ret_t pok_syscall_init ()
{
   pok_idt_set_gate (POK_SYSCALL_INT_NUMBER,
                     GDT_CORE_CODE_SEGMENT << 3,
                     (uint32_t) syscall_gate,
                     IDTE_INTERRUPT,
                     3);

   return (POK_ERRNO_OK);
}