Function ceva_fork

arch/ceva/src/common/ceva_fork.c:86–211

 ****************************************************************************/

pid_t ceva_fork(const uint32_t *regs)
{
#ifdef CONFIG_SCHED_WAITPID
  struct tcb_s *parent = this_task();
  struct tcb_s *child;
  size_t stacksize;
  const void *sp = regs + XCPTCONTEXT_REGS;
  void *newsp;
  uint32_t newfp;
  uint32_t stackutil;
  size_t argsize;
  void *argv;
  int ret;

  /* Allocate and initialize a TCB for the child task. */

  child = nxtask_setup_fork(parent->start, &argsize);
  if (!child)
    {
      serr("ERROR: nxtask_setup_fork failed\n");
      return (pid_t)ERROR;
    }

  sinfo("TCBs: Parent=%p Child=%p\n", parent, child);

  /* Get the size of the parent task's stack. */

  stacksize = parent->adj_stack_size;

  /* Allocate the stack for the TCB */

  ret = up_create_stack(child, stacksize + argsize,
                        parent->flags & TCB_FLAG_TTYPE_MASK);
  if (ret != OK)
    {
      serr("ERROR: up_create_stack failed: %d\n", ret);
      nxtask_abort_fork(child, -ret);
      return (pid_t)ERROR;
    }

  /* Allocate the memory and copy argument from parent task */

  argv = up_stack_frame(child, argsize);
  memcpy(argv, parent->stack_base_ptr, argsize);

  /* How much of the parent's stack was utilized?  The CEVA uses
   * a push-down stack so that the current stack pointer should
   * be lower than the initial, adjusted stack pointer.  The
   * stack usage should be the difference between those two.
   */

  DEBUGASSERT(parent->stack_base_ptr >= sp);
  stackutil = parent->stack_base_ptr - sp;

  sinfo("Parent: stacksize:%d stackutil:%d\n", stacksize, stackutil);

  /* Make some feeble effort to preserve the stack contents.  This is
   * feeble because the stack surely contains invalid pointers and other