s390: wire up rseq system call

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/Kconfig

@@ -160,6 +160,7 @@ config S390
 	select HAVE_OPROFILE
 	select HAVE_PERF_EVENTS
 	select HAVE_REGS_AND_STACK_ACCESS_API
+	select HAVE_RSEQ
 	select HAVE_SYSCALL_TRACEPOINTS
 	select HAVE_VIRT_CPU_ACCOUNTING
 	select MODULES_USE_ELF_RELA

arch/s390/kernel/compat_wrapper.c

@@ -183,3 +183,4 @@ COMPAT_SYSCALL_WRAP2(s390_guarded_storage, int, command, struct gs_cb *, gs_cb);
 COMPAT_SYSCALL_WRAP5(statx, int, dfd, const char __user *, path, unsigned, flags, unsigned, mask, struct statx __user *, buffer);
 COMPAT_SYSCALL_WRAP4(s390_sthyi, unsigned long, code, void __user *, info, u64 __user *, rc, unsigned long, flags);
 COMPAT_SYSCALL_WRAP5(kexec_file_load, int, kernel_fd, int, initrd_fd, unsigned long, cmdline_len, const char __user *, cmdline_ptr, unsigned long, flags)
+COMPAT_SYSCALL_WRAP4(rseq, struct rseq __user *, rseq, u32, rseq_len, int, flags, u32, sig)

arch/s390/kernel/entry.S

@@ -357,6 +357,10 @@ ENTRY(system_call)
 	stg	%r2,__PT_R2(%r11)		# store return value
 
 .Lsysc_return:
+#ifdef CONFIG_DEBUG_RSEQ
+	lgr	%r2,%r11
+	brasl	%r14,rseq_syscall
+#endif
 	LOCKDEP_SYS_EXIT
 .Lsysc_tif:
 	TSTMSK	__PT_FLAGS(%r11),_PIF_WORK

arch/s390/kernel/signal.c

@@ -498,7 +498,7 @@ void do_signal(struct pt_regs *regs)
 		}
 		/* No longer in a system call */
 		clear_pt_regs_flag(regs, PIF_SYSCALL);
-
+		rseq_signal_deliver(&ksig, regs);
 		if (is_compat_task())
 			handle_signal32(&ksig, oldset, regs);
 		else
@@ -537,4 +537,5 @@ void do_notify_resume(struct pt_regs *regs)
 {
 	clear_thread_flag(TIF_NOTIFY_RESUME);
 	tracehook_notify_resume(regs);
+	rseq_handle_notify_resume(NULL, regs);
 }

arch/s390/kernel/syscalls/syscall.tbl

@@ -390,3 +390,4 @@
 380  common	s390_sthyi		sys_s390_sthyi			compat_sys_s390_sthyi
 381  common	kexec_file_load		sys_kexec_file_load		compat_sys_kexec_file_load
 382  common	io_pgetevents		sys_io_pgetevents		compat_sys_io_pgetevents
+383  common	rseq			sys_rseq			compat_sys_rseq