text: /*
   * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
   * Licensed under the GPL
   */
  
  #include <linux/kernel.h>
  #include <linux/ptrace.h>
  #include <linux/seccomp.h>
  #include <kern_util.h>
  #include <sysdep/ptrace.h>
  #include <sysdep/ptrace_user.h>
  #include <sysdep/syscalls.h>
  #include <shared/timer-internal.h>
  
  void handle_syscall(struct uml_pt_regs *r)
  {
  	struct pt_regs *regs = container_of(r, struct pt_regs, regs);
  	int syscall;
  
  	/*
  	 * If we have infinite CPU resources, then make every syscall also a
  	 * preemption point, since we don't have any other preemption in this
  	 * case, and kernel threads would basically never run until userspace
  	 * went to sleep, even if said userspace interacts with the kernel in
  	 * various ways.
  	 */
  	if (time_travel_mode == TT_MODE_INFCPU)
  		schedule();
  
  	/* Initialize the syscall number and default return value. */
  	UPT_SYSCALL_NR(r) = PT_SYSCALL_NR(r->gp);
  	PT_REGS_SET_SYSCALL_RETURN(regs, -ENOSYS);
  
  	if (syscall_trace_enter(regs))
  		goto out;
  
  	/* Do the seccomp check after ptrace; failures should be fast. */
  	if (secure_computing(NULL) == -1)
  		goto out;
  
  	syscall = UPT_SYSCALL_NR(r);
  	if (syscall >= 0 && syscall <= __NR_syscall_max)
  		PT_REGS_SET_SYSCALL_RETURN(regs,
  				EXECUTE_SYSCALL(syscall, regs));
  
  out:
  	syscall_trace_leave(regs);
  }
  