Merge pull request #322 from laijs/host_task_stub

use host_task_stub() for host task

Author: tavip

arch/lkl/include/asm/sched.h

@@ -18,5 +18,6 @@ static inline void thread_sched_jb(void)
 }
 
 void switch_to_host_task(struct task_struct *);
+int host_task_stub(void *unused);
 
 #endif /*  _ASM_LKL_SCHED_H */

arch/lkl/kernel/syscalls.c

@@ -61,7 +61,7 @@ static int new_host_task(struct task_struct **task)
 
 	switch_to_host_task(host0);
 
-	pid = kernel_thread(NULL, NULL, CLONE_FLAGS);
+	pid = kernel_thread(host_task_stub, NULL, CLONE_FLAGS);
 	if (pid < 0)
 		return pid;
 

arch/lkl/kernel/threads.c

@@ -126,6 +126,11 @@ struct task_struct *__switch_to(struct task_struct *prev,
 	return abs_prev;
 }
 
+int host_task_stub(void *unused)
+{
+	return 0;
+}
+
 void switch_to_host_task(struct task_struct *task)
 {
 	if (current == task)
@@ -170,7 +175,7 @@ int copy_thread(unsigned long clone_flags, unsigned long esp,
 	struct thread_info *ti = task_thread_info(p);
 	struct thread_bootstrap_arg *tba;
 
-	if (!esp) {
+	if ((int (*)(void *))esp == host_task_stub) {
 		set_ti_thread_flag(ti, TIF_HOST_THREAD);
 		return 0;
 	}