um: add support for TIF_NOTIFY_SIGNAL

stable inclusion
from stable-v5.10.162
commit dc808ffd9778aa013c792bb2ed369b84e346b67f
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I7P7OH

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=dc808ffd9778aa013c792bb2ed369b84e346b67f

--------------------------------

[ Upstream commit a5b3cd32 ]

Wire up TIF_NOTIFY_SIGNAL handling for um.

Cc: linux-um@lists.infradead.org
Acked-By: NAnton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Nsanglipeng <sanglipeng1@jd.com>

arch/um/include/asm/thread_info.h

@@ -57,6 +57,7 @@ static inline struct thread_info *current_thread_info(void)
 #define TIF_SYSCALL_TRACE	0	/* syscall trace active */
 #define TIF_SIGPENDING		1	/* signal pending */
 #define TIF_NEED_RESCHED	2	/* rescheduling necessary */
+#define TIF_NOTIFY_SIGNAL	3	/* signal notifications exist */
 #define TIF_RESTART_BLOCK	4
 #define TIF_MEMDIE		5	/* is terminating due to OOM killer */
 #define TIF_SYSCALL_AUDIT	6
@@ -68,6 +69,7 @@ static inline struct thread_info *current_thread_info(void)
 #define _TIF_SYSCALL_TRACE	(1 << TIF_SYSCALL_TRACE)
 #define _TIF_SIGPENDING		(1 << TIF_SIGPENDING)
 #define _TIF_NEED_RESCHED	(1 << TIF_NEED_RESCHED)
+#define _TIF_NOTIFY_SIGNAL	(1 << TIF_NOTIFY_SIGNAL)
 #define _TIF_MEMDIE		(1 << TIF_MEMDIE)
 #define _TIF_SYSCALL_AUDIT	(1 << TIF_SYSCALL_AUDIT)
 #define _TIF_SECCOMP		(1 << TIF_SECCOMP)

arch/um/kernel/process.c

@@ -99,7 +99,8 @@ void interrupt_end(void)
 
 	if (need_resched())
 		schedule();
-	if (test_thread_flag(TIF_SIGPENDING))
+	if (test_thread_flag(TIF_SIGPENDING) ||
+	    test_thread_flag(TIF_NOTIFY_SIGNAL))
 		do_signal(regs);
 	if (test_thread_flag(TIF_NOTIFY_RESUME))
 		tracehook_notify_resume(regs);