s390: add support for TIF_NOTIFY_SIGNAL

Wire up TIF_NOTIFY_SIGNAL handling for s390.

Cc: linux-s390@vger.kernel.org
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Acked-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

arch/s390/include/asm/thread_info.h

@@ -65,6 +65,7 @@ void arch_setup_new_exec(void);
 #define TIF_GUARDED_STORAGE	4	/* load guarded storage control block */
 #define TIF_PATCH_PENDING	5	/* pending live patching update */
 #define TIF_PGSTE		6	/* New mm's will use 4K page tables */
+#define TIF_NOTIFY_SIGNAL	7	/* signal notifications exist */
 #define TIF_ISOLATE_BP		8	/* Run process with isolated BP */
 #define TIF_ISOLATE_BP_GUEST	9	/* Run KVM guests with isolated BP */
 
@@ -82,6 +83,7 @@ void arch_setup_new_exec(void);
 #define TIF_SYSCALL_TRACEPOINT	27	/* syscall tracepoint instrumentation */
 
 #define _TIF_NOTIFY_RESUME	BIT(TIF_NOTIFY_RESUME)
+#define _TIF_NOTIFY_SIGNAL	BIT(TIF_NOTIFY_SIGNAL)
 #define _TIF_SIGPENDING		BIT(TIF_SIGPENDING)
 #define _TIF_NEED_RESCHED	BIT(TIF_NEED_RESCHED)
 #define _TIF_UPROBE		BIT(TIF_UPROBE)

arch/s390/kernel/entry.S

@@ -52,7 +52,8 @@ STACK_SIZE  = 1 << STACK_SHIFT
 STACK_INIT = STACK_SIZE - STACK_FRAME_OVERHEAD - __PT_SIZE
 
 _TIF_WORK	= (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_NEED_RESCHED | \
-		   _TIF_UPROBE | _TIF_GUARDED_STORAGE | _TIF_PATCH_PENDING)
+		   _TIF_UPROBE | _TIF_GUARDED_STORAGE | _TIF_PATCH_PENDING | \
+		   _TIF_NOTIFY_SIGNAL)
 _TIF_TRACE	= (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | _TIF_SECCOMP | \
 		   _TIF_SYSCALL_TRACEPOINT)
 _CIF_WORK	= (_CIF_ASCE_PRIMARY | _CIF_ASCE_SECONDARY | _CIF_FPU)
@@ -463,8 +464,8 @@ ENTRY(system_call)
 #endif
 	TSTMSK	__PT_FLAGS(%r11),_PIF_SYSCALL_RESTART
 	jo	.Lsysc_syscall_restart
-	TSTMSK	__TI_flags(%r12),_TIF_SIGPENDING
-	jo	.Lsysc_sigpending
+	TSTMSK	__TI_flags(%r12),(_TIF_SIGPENDING|_TIF_NOTIFY_SIGNAL)
+	jnz	.Lsysc_sigpending
 	TSTMSK	__TI_flags(%r12),_TIF_NOTIFY_RESUME
 	jo	.Lsysc_notify_resume
 	TSTMSK	__LC_CPU_FLAGS,(_CIF_ASCE_PRIMARY|_CIF_ASCE_SECONDARY)
@@ -855,8 +856,8 @@ ENTRY(io_int_handler)
 	TSTMSK	__TI_flags(%r12),_TIF_PATCH_PENDING
 	jo	.Lio_patch_pending
 #endif
-	TSTMSK	__TI_flags(%r12),_TIF_SIGPENDING
-	jo	.Lio_sigpending
+	TSTMSK	__TI_flags(%r12),(_TIF_SIGPENDING|_TIF_NOTIFY_SIGNAL)
+	jnz	.Lio_sigpending
 	TSTMSK	__TI_flags(%r12),_TIF_NOTIFY_RESUME
 	jo	.Lio_notify_resume
 	TSTMSK	__TI_flags(%r12),_TIF_GUARDED_STORAGE

arch/s390/kernel/signal.c

@@ -472,7 +472,7 @@ void do_signal(struct pt_regs *regs)
 	current->thread.system_call =
 		test_pt_regs_flag(regs, PIF_SYSCALL) ? regs->int_code : 0;
 
-	if (get_signal(&ksig)) {
+	if (test_thread_flag(TIF_SIGPENDING) && get_signal(&ksig)) {
 		/* Whee!  Actually deliver the signal.  */
 		if (current->thread.system_call) {
 			regs->int_code = current->thread.system_call;