diff --git a/include/sys/syscall.h b/include/sys/syscall.h
index 8608263..2d9a151 100644
--- a/include/sys/syscall.h
+++ b/include/sys/syscall.h
@@ -3,6 +3,13 @@
 #define SYSCALL_NR_READ         0
 #define SYSCALL_NR_WRITE        1
 
+#define SYSCALL_NRX_SIGENTRY    13
+void sys_sigentry(uintptr_t entry);
+#define SYSCALL_NR_SIGRETURN    15
+void sys_sigreturn(void);
+#define SYSCALL_NRX_SUICIDE     253
+void sys_suicide(void);
+
 #define SYSCALL_NR_FORK         57
 int sys_fork(void *ctx);
 #define SYSCALL_NR_EXIT         60
diff --git a/include/sys/thread.h b/include/sys/thread.h
index 0cebdc5..c9083c0 100644
--- a/include/sys/thread.h
+++ b/include/sys/thread.h
@@ -28,6 +28,9 @@ struct thread {
     uint64_t sleep_deadline;
     struct thread *wait_prev, *wait_next;
 
+    // Signal
+    uintptr_t signal_entry;
+
     // State
     pid_t pid;
     enum thread_state state;
diff --git a/sys/amd64/sched_s.S b/sys/amd64/sched_s.S
index 1781fd1..f06a35f 100644
--- a/sys/amd64/sched_s.S
+++ b/sys/amd64/sched_s.S
@@ -100,3 +100,60 @@ context_switch_first:
 
     ret
 .size context_switch_to, . - context_switch_to
+
+
+
+
+
+
+
+.global context_sigreturn
+context_sigreturn:
+    movq tmp0(%rip), %rsp
+
+    popq %rbx
+    popq %rbp
+    popq %r12
+    popq %r13
+    popq %r14
+    popq %r15
+
+    ret
+
+
+.global context_sigenter
+context_sigenter:
+    // %rdi - entry
+    // %rsi - stack
+    pushq %r15
+    pushq %r14
+    pushq %r13
+    pushq %r12
+    pushq %rbp
+    pushq %rbx
+
+    // Use alternate TSS.RSP0 so syscall frame does not get overwritten
+    movq get_cpu(CPU_THREAD), %rbx
+    movq %rsp, tmp0(%rip)
+    movq %rsp, THREAD_RSP0(%rbx)
+    movq %rsp, THREAD_RSP0_TOP(%rbx)
+    movq THREAD_RSP0_TOP(%rbx), %rbx
+    movq get_cpu(CPU_TSS), %r12
+    movq %rbx, TSS_RSP0(%r12)
+
+    pushq $0x1B
+    pushq %rsi
+
+    pushq $0x200
+
+    pushq $0x23
+    pushq %rdi
+
+    iretq
+
+.section .bss
+tmp0:
+    .quad 0
+//    0xffffff000528df90
+// r15 = 0, r14 = 0, r13 = 0, r12 = 0,
+// rbp = 0xffffff000528dfd8, rbx = 0x0
diff --git a/sys/amd64/syscall.c b/sys/amd64/syscall.c
index d765b14..d0d0815 100644
--- a/sys/amd64/syscall.c
+++ b/sys/amd64/syscall.c
@@ -25,6 +25,10 @@ void *syscall_table[256] = {
     [SYSCALL_NR_READ] = sys_read,
     [SYSCALL_NR_WRITE] = sys_write,
 
+    [SYSCALL_NRX_SUICIDE] = sys_suicide,
+    [SYSCALL_NRX_SIGENTRY] = sys_sigentry,
+    [SYSCALL_NR_SIGRETURN] = sys_sigreturn,
+
     [SYSCALL_NR_EXIT] = sys_exit,
 
     [SYSCALL_NR_DEBUG_SLEEP] = sys_debug_sleep,
diff --git a/sys/sched.c b/sys/sched.c
index 080cd09..4101570 100644
--- a/sys/sched.c
+++ b/sys/sched.c
@@ -166,6 +166,10 @@ void yield(void) {
         from->state = THREAD_READY;
     }
 
+    if (to->pid == 1) {
+        kinfo("%p\n", to->data.rsp0);
+    }
+
     to->state = THREAD_RUNNING;
     get_cpu()->thread = to;
     context_switch_to(to, from);
diff --git a/sys/thread.c b/sys/thread.c
index 2255d51..a98384a 100644
--- a/sys/thread.c
+++ b/sys/thread.c
@@ -344,3 +344,32 @@ void thread_sleep(struct thread *thr, uint64_t deadline) {
     timer_add_sleep(thr);
     sched_unqueue(thr, THREAD_WAITING);
 }
+
+extern void context_sigenter(uintptr_t entry, uintptr_t stack);
+extern void context_sigreturn(void);
+static char fuck[4096];
+
+void sys_sigreturn(void) {
+    context_sigreturn();
+}
+
+void sys_suicide(void) {
+    struct thread *thr = thread_self;
+    _assert(thr);
+    kinfo("Enter\n");
+    uintptr_t old_rsp0_top = thr->data.rsp0_top;
+    thr->data.rsp0_top = (uintptr_t) &fuck[4096];
+
+    context_sigenter(thr->signal_entry, 0x100500);
+
+    thr->data.rsp0_top = old_rsp0_top;
+
+    kinfo("Leave\n");
+}
+
+void sys_sigentry(uintptr_t entry) {
+    struct thread *thr = thread_self;
+    _assert(thr);
+
+    thr->signal_entry = entry;
+}