um: add TIF_NOTIFY_RESUME

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

arch/um/include/asm/thread_info.h

@@ -71,6 +71,7 @@ static inline struct thread_info *current_thread_info(void)
 #define TIF_MEMDIE		5	/* is terminating due to OOM killer */
 #define TIF_SYSCALL_AUDIT	6
 #define TIF_RESTORE_SIGMASK	7
+#define TIF_NOTIFY_RESUME	8
 
 #define _TIF_SYSCALL_TRACE	(1 << TIF_SYSCALL_TRACE)
 #define _TIF_SIGPENDING		(1 << TIF_SIGPENDING)

arch/um/kernel/process.c

@@ -18,6 +18,7 @@
 #include <linux/seq_file.h>
 #include <linux/tick.h>
 #include <linux/threads.h>
+#include <linux/tracehook.h>
 #include <asm/current.h>
 #include <asm/pgtable.h>
 #include <asm/mmu_context.h>
@@ -114,8 +115,13 @@ void interrupt_end(void)
 {
 	if (need_resched())
 		schedule();
-	if (test_tsk_thread_flag(current, TIF_SIGPENDING))
+	if (test_thread_flag(TIF_SIGPENDING))
 		do_signal();
+	if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME)) {
+		tracehook_notify_resume(&current->thread.regs);
+		if (current->replacement_session_keyring)
+			key_replace_session_keyring();
+	}
 }
 
 void exit_thread(void)