sh: Handle cases where setup{_rt,}_frame() fail on SH-5 signal delivery.

Presently these cases are not handled properly due to the return value
not being passed back. This needs to be correct to get proper behaviour
out of things like the tracehook signal notifier, amongst others.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

arch/sh/kernel/signal_64.c

@@ -2,7 +2,7 @@
  * arch/sh/kernel/signal_64.c
  *
  * Copyright (C) 2000, 2001  Paolo Alberelli
- * Copyright (C) 2003  Paul Mundt
+ * Copyright (C) 2003 - 2008  Paul Mundt
  * Copyright (C) 2004  Richard Curnow
  *
  * This file is subject to the terms and conditions of the GNU General Public
@@ -43,7 +43,7 @@
 
 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
 
-static void
+static int
 handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
 		sigset_t *oldset, struct pt_regs * regs);
 
@@ -80,15 +80,13 @@ static int do_signal(struct pt_regs *regs, sigset_t *oldset)
 		oldset = &current->blocked;
 
 	signr = get_signal_to_deliver(&info, &ka, regs, 0);
-
 	if (signr > 0) {
 		/* Whee!  Actually deliver the signal.  */
-		handle_signal(signr, &info, &ka, oldset, regs);
-
+		if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
 			/*
-		 * If a signal was successfully delivered, the saved sigmask
-		 * is in its frame, and we can clear the TIF_RESTORE_SIGMASK
-		 * flag.
+			 * If a signal was successfully delivered, the
+			 * saved sigmask is in its frame, and we can
+			 * clear the TIF_RESTORE_SIGMASK flag.
 			 */
 			if (test_thread_flag(TIF_RESTORE_SIGMASK))
 				clear_thread_flag(TIF_RESTORE_SIGMASK);
@@ -96,6 +94,7 @@ static int do_signal(struct pt_regs *regs, sigset_t *oldset)
 			tracehook_signal_handler(signr, &info, &ka, regs, 0);
 			return 1;
 		}
+	}
 
 no_signal:
 	/* Did we come from a system call? */
@@ -504,7 +503,7 @@ get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size)
 void sa_default_restorer(void);		/* See comments below */
 void sa_default_rt_restorer(void);	/* See comments below */
 
-static void setup_frame(int sig, struct k_sigaction *ka,
+static int setup_frame(int sig, struct k_sigaction *ka,
 		       sigset_t *set, struct pt_regs *regs)
 {
 	struct sigframe __user *frame;
@@ -596,22 +595,20 @@ static void setup_frame(int sig, struct k_sigaction *ka,
 
 	set_fs(USER_DS);
 
-#if DEBUG_SIG
 	/* Broken %016Lx */
-	printk("SIG deliver (#%d,%s:%d): sp=%p pc=%08Lx%08Lx link=%08Lx%08Lx\n",
-		signal,
-		current->comm, current->pid, frame,
+	pr_debug("SIG deliver (#%d,%s:%d): sp=%p pc=%08Lx%08Lx link=%08Lx%08Lx\n",
+		 signal, current->comm, current->pid, frame,
 		 regs->pc >> 32, regs->pc & 0xffffffff,
 		 DEREF_REG_PR >> 32, DEREF_REG_PR & 0xffffffff);
-#endif
 
-	return;
+	return 0;
 
 give_sigsegv:
 	force_sigsegv(sig, current);
+	return -EFAULT;
 }
 
-static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
+static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 			  sigset_t *set, struct pt_regs *regs)
 {
 	struct rt_sigframe __user *frame;
@@ -702,29 +699,28 @@ static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 
 	set_fs(USER_DS);
 
-#if DEBUG_SIG
-	/* Broken %016Lx */
-	printk("SIG deliver (#%d,%s:%d): sp=%p pc=%08Lx%08Lx link=%08Lx%08Lx\n",
-		signal,
-		current->comm, current->pid, frame,
+	pr_debug("SIG deliver (#%d,%s:%d): sp=%p pc=%08Lx%08Lx link=%08Lx%08Lx\n",
+		 signal, current->comm, current->pid, frame,
 		 regs->pc >> 32, regs->pc & 0xffffffff,
 		 DEREF_REG_PR >> 32, DEREF_REG_PR & 0xffffffff);
-#endif
 
-	return;
+	return 0;
 
 give_sigsegv:
 	force_sigsegv(sig, current);
+	return -EFAULT;
 }
 
 /*
  * OK, we're invoking a handler
  */
 
-static void
+static int
 handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
 		sigset_t *oldset, struct pt_regs * regs)
 {
+	int ret;
+
 	/* Are we from a system call? */
 	if (regs->syscall_nr >= 0) {
 		/* If so, check system call restarting.. */
@@ -748,16 +744,23 @@ handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
 
 	/* Set up the stack frame */
 	if (ka->sa.sa_flags & SA_SIGINFO)
-		setup_rt_frame(sig, ka, info, oldset, regs);
+		ret = setup_rt_frame(sig, ka, info, oldset, regs);
 	else
-		setup_frame(sig, ka, oldset, regs);
+		ret = setup_frame(sig, ka, oldset, regs);
 
+	if (ka->sa.sa_flags & SA_ONESHOT)
+		ka->sa.sa_handler = SIG_DFL;
+
+	if (ret == 0) {
 		spin_lock_irq(&current->sighand->siglock);
 		sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
 		if (!(ka->sa.sa_flags & SA_NODEFER))
 			sigaddset(&current->blocked,sig);
 		recalc_sigpending();
 		spin_unlock_irq(&current->sighand->siglock);
+	}
+
+	return ret;
 }
 
 asmlinkage void do_notify_resume(struct pt_regs *regs, unsigned long thread_info_flags)