+/*
+ * For function-return probes, init_kprobes() establishes a probepoint
+ * here. When a retprobed function returns, this probe is hit and
+ * trampoline_probe_handler() runs, calling the kretprobe's handler.
+ */
+ void kretprobe_trampoline_holder(void)
+ {
+ asm volatile ( ".global kretprobe_trampoline\n"
+ "kretprobe_trampoline: \n"
+ "nop\n");
+ }
+
+/*
+ * Called when we hit the probe point at kretprobe_trampoline
+ */
+int trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
+{
+ struct task_struct *tsk;
+ struct kretprobe_instance *ri;
+ struct hlist_head *head;
+ struct hlist_node *node;
+ unsigned long *sara = (unsigned long *)regs->rsp - 1;
+
+ tsk = arch_get_kprobe_task(sara);
+ head = kretprobe_inst_table_head(tsk);
+
+ hlist_for_each_entry(ri, node, head, hlist) {
+ if (ri->stack_addr == sara && ri->rp) {
+ if (ri->rp->handler)
+ ri->rp->handler(ri, regs);
+ }
+ }
+ return 0;
+}
+
+void trampoline_post_handler(struct kprobe *p, struct pt_regs *regs,
+ unsigned long flags)
+{
+ struct kretprobe_instance *ri;
+ /* RA already popped */
+ unsigned long *sara = ((unsigned long *)regs->rsp) - 1;
+
+ while ((ri = get_rp_inst(sara))) {
+ regs->rip = (unsigned long)ri->ret_addr;
+ recycle_rp_inst(ri);
+ }
+ regs->eflags &= ~TF_MASK;
+}
+