um: fill the handlers array at build time

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Richard Weinberger <richard@nod.at>

arch/um/include/shared/os.h

@@ -225,7 +225,7 @@ extern char *get_umid(void);
 extern void timer_init(void);
 extern void set_sigstack(void *sig_stack, int size);
 extern void remove_sigstack(void);
-extern void set_handler(int sig, void (*handler)(int));
+extern void set_handler(int sig);
 extern int change_sig(int signal, int on);
 extern void block_signals(void);
 extern void unblock_signals(void);

arch/um/os-Linux/process.c

@@ -235,13 +235,13 @@ int __init can_drop_memory(void)
 
 void init_new_thread_signals(void)
 {
-	set_handler(SIGSEGV, (__sighandler_t) sig_handler);
-	set_handler(SIGTRAP, (__sighandler_t) sig_handler);
-	set_handler(SIGFPE, (__sighandler_t) sig_handler);
-	set_handler(SIGILL, (__sighandler_t) sig_handler);
-	set_handler(SIGBUS, (__sighandler_t) sig_handler);
+	set_handler(SIGSEGV);
+	set_handler(SIGTRAP);
+	set_handler(SIGFPE);
+	set_handler(SIGILL);
+	set_handler(SIGBUS);
 	signal(SIGHUP, SIG_IGN);
-	set_handler(SIGIO, (__sighandler_t) sig_handler);
+	set_handler(SIGIO);
 	signal(SIGWINCH, SIG_IGN);
 	signal(SIGTERM, SIG_DFL);
 }

arch/um/os-Linux/signal.c

@@ -111,7 +111,7 @@ void alarm_handler(int sig, struct sigcontext *sc)
 
 void timer_init(void)
 {
-	set_handler(SIGVTALRM, (__sighandler_t) alarm_handler);
+	set_handler(SIGVTALRM);
 }
 
 void set_sigstack(void *sig_stack, int size)
@@ -124,7 +124,17 @@ void set_sigstack(void *sig_stack, int size)
 		panic("enabling signal stack failed, errno = %d\n", errno);
 }
 
-static void (*handlers[_NSIG])(int sig, struct sigcontext *sc);
+static void (*handlers[_NSIG])(int sig, struct sigcontext *sc) = {
+	[SIGSEGV] = sig_handler,
+	[SIGBUS] = sig_handler,
+	[SIGILL] = sig_handler,
+	[SIGFPE] = sig_handler,
+	[SIGTRAP] = sig_handler,
+
+	[SIGIO] = sig_handler,
+	[SIGWINCH] = sig_handler,
+	[SIGVTALRM] = alarm_handler
+};
 
 static void handle_signal(int sig, struct sigcontext *sc)
 {
@@ -173,13 +183,12 @@ static void hard_handler(int sig, siginfo_t *info, void *p)
 	handle_signal(sig, (struct sigcontext *) &uc->uc_mcontext);
 }
 
-void set_handler(int sig, void (*handler)(int))
+void set_handler(int sig)
 {
 	struct sigaction action;
 	int flags = SA_SIGINFO | SA_ONSTACK;
 	sigset_t sig_mask;
 
-	handlers[sig] = (void (*)(int, struct sigcontext *)) handler;
 	action.sa_sigaction = hard_handler;
 
 	/* block irq ones */

arch/um/os-Linux/skas/process.c

@@ -659,7 +659,7 @@ int start_idle_thread(void *stack, jmp_buf *switch_buf)
 {
 	int n;
 
-	set_handler(SIGWINCH, (__sighandler_t) sig_handler);
+	set_handler(SIGWINCH);
 
 	/*
 	 * Can't use UML_SETJMP or UML_LONGJMP here because they save