diff -Nrc uml-linux-2.4.22/arch/um/kernel/process.c sysemu-uml-linux-2.4.22/arch/um/kernel/process.c
*** uml-linux-2.4.22/arch/um/kernel/process.c	Tue Oct 14 15:28:28 2003
--- sysemu-uml-linux-2.4.22/arch/um/kernel/process.c	Thu Dec  4 20:14:33 2003
***************
*** 222,227 ****
--- 222,243 ----
  	}
  	stop_ptraced_child(pid, stack, 0);
  	printk("OK\n");
+ 
+ #ifdef PTRACE_SYSEMU
+ 	printk("Checking syscall emulation patch for ptrace...");
+ 
+ 	use_sysemu = 0;
+ 	pid = start_ptraced_child(&stack);
+ 	if(ptrace(PTRACE_SYSEMU, pid, 0, 0) >= 0)
+ 	{
+ 		printk("OK\n");
+         	use_sysemu = 1;
+ 	}
+ 	else
+ 		printk("missing\n");
+ 
+ 	stop_ptraced_child(pid, stack, 0);
+ #endif
  }
  
  int run_kernel_thread(int (*fn)(void *), void *arg, void **jmp_ptr)
diff -Nrc uml-linux-2.4.22/arch/um/kernel/skas/include/ptrace-skas.h sysemu-uml-linux-2.4.22/arch/um/kernel/skas/include/ptrace-skas.h
*** uml-linux-2.4.22/arch/um/kernel/skas/include/ptrace-skas.h	Tue Oct 14 15:28:28 2003
--- sysemu-uml-linux-2.4.22/arch/um/kernel/skas/include/ptrace-skas.h	Thu Dec  4 20:15:34 2003
***************
*** 10,15 ****
--- 10,22 ----
  
  #ifdef UML_CONFIG_MODE_SKAS
  
+ /* syscall emulation path in ptrace */
+ 
+ #ifndef PTRACE_SYSEMU
+ #define PTRACE_SYSEMU 25
+ #endif
+ extern int use_sysemu;
+ 
  #include "skas_ptregs.h"
  
  #define HOST_FRAME_SIZE 17
diff -Nrc uml-linux-2.4.22/arch/um/kernel/skas/process.c sysemu-uml-linux-2.4.22/arch/um/kernel/skas/process.c
*** uml-linux-2.4.22/arch/um/kernel/skas/process.c	Wed Dec  3 18:53:54 2003
--- sysemu-uml-linux-2.4.22/arch/um/kernel/skas/process.c	Fri Dec  5 17:57:03 2003
***************
*** 27,32 ****
--- 27,36 ----
  #include "skas_ptrace.h"
  #include "chan_user.h"
  
+ #ifdef PTRACE_SYSEMU
+ int use_sysemu = 0;
+ #endif
+ 
  int is_skas_winch(int pid, int fd, void *data)
  {
  	if(pid != getpid())
***************
*** 65,85 ****
  		return;
  	}
  
! 	err = ptrace(PTRACE_POKEUSER, pid, PT_SYSCALL_NR_OFFSET, __NR_getpid);
! 	if(err < 0)
! 	        panic("handle_trap - nullifying syscall failed errno = %d\n", 
! 		      errno);
  
! 	err = ptrace(PTRACE_SYSCALL, pid, 0, 0);
! 	if(err < 0)
! 	        panic("handle_trap - continuing to end of syscall failed, "
! 		      "errno = %d\n", errno);
! 
! 	err = waitpid(pid, &status, WUNTRACED);
! 	if((err < 0) || !WIFSTOPPED(status) || (WSTOPSIG(status) != SIGTRAP))
! 		panic("handle_trap - failed to wait at end of syscall, "
! 		      "errno = %d, status = %d\n", errno, status);
  
  	handle_syscall(regs);
  }
  
--- 69,91 ----
  		return;
  	}
  
! 	if (!use_sysemu)
! 	{
! 		err = ptrace(PTRACE_POKEUSER, pid, PT_SYSCALL_NR_OFFSET, __NR_getpid);
! 		if(err < 0)
! 	        	panic("handle_trap - nullifying syscall failed errno = %d\n", 
! 		      	errno);
  
! 		err = ptrace(PTRACE_SYSCALL, pid, 0, 0);
! 		if(err < 0)
! 	        	panic("handle_trap - continuing to end of syscall failed, "
! 		      	"errno = %d\n", errno);
  
+ 		err = waitpid(pid, &status, WUNTRACED);
+ 		if((err < 0) || !WIFSTOPPED(status) || (WSTOPSIG(status) != SIGTRAP))
+ 			panic("handle_trap - failed to wait at end of syscall, "
+ 		      	"errno = %d, status = %d\n", errno, status);
+ 	}
  	handle_syscall(regs);
  }
  
***************
*** 134,140 ****
--- 140,154 ----
  
  	restore_registers(regs);
  		
+ #ifdef PTRACE_SYSEMU
+ 	if (use_sysemu)
+ 		err = ptrace(PTRACE_SYSEMU, userspace_pid, 0, 0);
+ 	else
+ 		err = ptrace(PTRACE_SYSCALL, userspace_pid, 0, 0);
+ #else
  	err = ptrace(PTRACE_SYSCALL, userspace_pid, 0, 0);
+ #endif
+ 
  	if(err)
  		panic("userspace - PTRACE_SYSCALL failed, errno = %d\n", 
  		       errno);
***************
*** 172,179 ****
--- 186,202 ----
  
  		restore_registers(regs);
  
+ #ifdef PTRACE_SYSEMU
+ 		if (use_sysemu)
+ 			op = singlestepping_skas() ? PTRACE_SINGLESTEP : 
+ 				PTRACE_SYSEMU;
+ 		else
+ 			op = singlestepping_skas() ? PTRACE_SINGLESTEP : 
+ 				PTRACE_SYSCALL;
+ #else
  		op = singlestepping_skas() ? PTRACE_SINGLESTEP : 
  			PTRACE_SYSCALL;
+ #endif
  		err = ptrace(op, userspace_pid, 0, 0);
  		if(err)
  			panic("userspace - PTRACE_SYSCALL failed, "