diff --git a/Makefile b/Makefile
index e869980..b908f00 100644
--- a/Makefile
+++ b/Makefile
@@ -3,8 +3,7 @@
 
 PROJECTS:=projects/hello \
 	  projects/trapped \
-	  projects/ping-pong \
-	  projects/demonstrator
+	  projects/ping-pong
 
 all: ${PROJECTS}
 
diff --git a/kernel/inc/trap.h b/kernel/inc/trap.h
index 3b3edb0..bcb391d 100644
--- a/kernel/inc/trap.h
+++ b/kernel/inc/trap.h
@@ -11,4 +11,5 @@
 
 void trap_handle(void);
 void trap_entry(void) NORETURN;
-void trap_exit(void) NORETURN;
+void trap_resume(proc_t *proc) NORETURN;
+void trap_return(proc_t *proc) NORETURN;
diff --git a/kernel/src/head.S b/kernel/src/head.S
index 4938b23..1f981e3 100644
--- a/kernel/src/head.S
+++ b/kernel/src/head.S
@@ -71,7 +71,7 @@ head_exit:
 	la	t0,trap_entry
 	csrw	mtvec,t0
 	csrw	mscratch,0
-	la	ra,trap_exit
+	la	ra,trap_resume
 	tail	sched
 
 __hang:
diff --git a/kernel/src/trap.S b/kernel/src/trap.S
index ce5f675..074bbf6 100644
--- a/kernel/src/trap.S
+++ b/kernel/src/trap.S
@@ -4,7 +4,8 @@
 #include "csr.h"
 
 .globl trap_entry
-.globl trap_exit
+.globl trap_resume
+.globl trap_return
 
 .type trap_entry, @function
 .type trap_exit, @function
@@ -63,7 +64,7 @@ trap_entry:
 	csrr	a2,mtval
 	call	trap_handler
 
-trap_exit:
+trap_resume:
 	ld	s0,PROC_PMPADDR0(a0)
 	ld	s1,PROC_PMPADDR1(a0)
 	ld	s2,PROC_PMPADDR2(a0)
@@ -72,7 +73,6 @@ trap_exit:
 	ld	s5,PROC_PMPADDR5(a0)
 	ld	s6,PROC_PMPADDR6(a0)
 	ld	s7,PROC_PMPADDR7(a0)
-	fence
 	ld	s8,PROC_PMPCFG0(a0)
 	csrw	pmpaddr0,s0
 	csrw	pmpaddr1,s1
@@ -84,6 +84,7 @@ trap_exit:
 	csrw	pmpaddr7,s7
 	csrw	pmpcfg0,s8
 
+trap_return:
 	ld	t0,PROC_PC(a0)
 	ld	t1,PROC_A0(a0)
 	csrw	mepc,t0
diff --git a/kernel/src/trap.c b/kernel/src/trap.c
index eba4160..c4c18ef 100644
--- a/kernel/src/trap.c
+++ b/kernel/src/trap.c
@@ -8,14 +8,15 @@ proc_t *trap_handler(proc_t *proc, uint64_t mcause, uint64_t mtval)
 {
 	if (mcause == 8) {
 		proc_t *next = syscall_handler(proc);
-		if (next != proc)
-			proc_release(proc);
+		if (next == proc)
+			trap_return(proc);
+		proc_release(proc);
 		if (next)
 			return next;
 		return sched();
 	} else if ((int64_t)mcause < 0) {
 		return interrupt_handler(proc, mcause, mtval);
 	} else {
-		return exception_handler(proc, mcause, mtval);
+		trap_return(exception_handler(proc, mcause, mtval));
 	}
 }