arm64: Remove unimplemented syscall log message

commit 1962682d2b2fbe6cfa995a85c53c069fadda473e upstream.

Stop printing a (ratelimited) kernel message for each instance of an
unimplemented syscall being called. Userland making an unimplemented
syscall is not necessarily misbehaviour and to be expected with a
current userland running on an older kernel. Also, the current message
looks scary to users but does not actually indicate a real problem nor
help them narrow down the cause. Just rely on sys_ni_syscall() to return
-ENOSYS.

Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Michael Weiser <michael.weiser@gmx.de>
Signed-off-by: Will Deacon <will.deacon@arm.com>
[bwh: Backported to 3.16: Deleted code was slightly different]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

1 files changed, 0 insertions, 8 deletions

diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
index 33937b7fbfef..d368cc98bcdb 100644
--- a/arch/arm64/kernel/traps.c
+++ b/arch/arm64/kernel/traps.c
@@ -251,14 +251,6 @@ asmlinkage long do_ni_syscall(struct pt_regs *regs)
 	}
 #endif
 
-	if (show_unhandled_signals && printk_ratelimit()) {
-		pr_info("%s[%d]: syscall %d\n", current->comm,
-			task_pid_nr(current), (int)regs->syscallno);
-		dump_instr("", regs);
-		if (user_mode(regs))
-			__show_regs(regs);
-	}
-
 	return sys_ni_syscall();
 }