ptrace: Remove tracehook_signal_handler

The two line function tracehook_signal_handler is only called from
signal_delivered.  Expand it inline in signal_delivered and remove it.
Just to make it easier to understand what is going on.

Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lkml.kernel.org/r/20220309162454.123006-5-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

arch/Kconfig

@@ -219,7 +219,6 @@ config TRACE_IRQFLAGS_SUPPORT
 #	CORE_DUMP_USE_REGSET	#define'd in linux/elf.h
 #	TIF_SYSCALL_TRACE	calls ptrace_report_syscall_{entry,exit}
 #	TIF_NOTIFY_RESUME	calls tracehook_notify_resume()
-#	signal delivery		calls tracehook_signal_handler()
 #
 config HAVE_ARCH_TRACEHOOK
 	bool

include/linux/tracehook.h

@@ -52,23 +52,6 @@
 struct linux_binprm;
 
 
-/**
- * tracehook_signal_handler - signal handler setup is complete
- * @stepping:		nonzero if debugger single-step or block-step in use
- *
- * Called by the arch code after a signal handler has been set up.
- * Register and stack state reflects the user handler about to run.
- * Signal mask changes have already been made.
- *
- * Called without locks, shortly before returning to user mode
- * (or handling more signals).
- */
-static inline void tracehook_signal_handler(int stepping)
-{
-	if (stepping)
-		ptrace_notify(SIGTRAP);
-}
-
 /**
  * set_notify_resume - cause tracehook_notify_resume() to be called
  * @task:		task that will call tracehook_notify_resume()

kernel/signal.c

@@ -2898,7 +2898,8 @@ static void signal_delivered(struct ksignal *ksig, int stepping)
 	set_current_blocked(&blocked);
 	if (current->sas_ss_flags & SS_AUTODISARM)
 		sas_ss_reset(current);
-	tracehook_signal_handler(stepping);
+	if (stepping)
+		ptrace_notify(SIGTRAP);
 }
 
 void signal_setup_done(int failed, struct ksignal *ksig, int stepping)