Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal

Pull third pile of signal handling patches from Al Viro:
 "This time it's mostly helpers and conversions to them; there's a lot
  of stuff remaining in the tree, but that'll either go in -rc2
  (isolated bug fixes, ideally via arch maintainers' trees) or will sit
  there until the next cycle."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal:
  x86: get rid of calling do_notify_resume() when returning to kernel mode
  blackfin: check __get_user() return value
  whack-a-mole with TIF_FREEZE
  FRV: Optimise the system call exit path in entry.S [ver #2]
  FRV: Shrink TIF_WORK_MASK [ver #2]
  FRV: Prevent syscall exit tracing and notify_resume at end of kernel exceptions
  new helper: signal_delivered()
  powerpc: get rid of restore_sigmask()
  most of set_current_blocked() callers want SIGKILL/SIGSTOP removed from set
  set_restore_sigmask() is never called without SIGPENDING (and never should be)
  TIF_RESTORE_SIGMASK can be set only when TIF_SIGPENDING is set
  don't call try_to_freeze() from do_signal()
  pull clearing RESTORE_SIGMASK into block_sigmask()
  sh64: failure to build sigframe != signal without handler
  openrisc: tracehook_signal_handler() is supposed to be called on success
  new helper: sigmask_to_save()
  new helper: restore_saved_sigmask()
  new helpers: {clear,test,test_and_clear}_restore_sigmask()
  HAVE_RESTORE_SIGMASK is defined on all architectures now

2 files changed, 22 insertions, 30 deletions

diff --git a/arch/ia64/include/asm/thread_info.h b/arch/ia64/include/asm/thread_info.h
index 310d973..f7ee853 100644
--- a/arch/ia64/include/asm/thread_info.h
+++ b/arch/ia64/include/asm/thread_info.h
@@ -141,7 +141,23 @@ static inline void set_restore_sigmask(void)
 {
 	struct thread_info *ti = current_thread_info();
 	ti->status |= TS_RESTORE_SIGMASK;
-	set_bit(TIF_SIGPENDING, &ti->flags);
+	WARN_ON(!test_bit(TIF_SIGPENDING, &ti->flags));
+}
+static inline void clear_restore_sigmask(void)
+{
+	current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
+}
+static inline bool test_restore_sigmask(void)
+{
+	return current_thread_info()->status & TS_RESTORE_SIGMASK;
+}
+static inline bool test_and_clear_restore_sigmask(void)
+{
+	struct thread_info *ti = current_thread_info();
+	if (!(ti->status & TS_RESTORE_SIGMASK))
+		return false;
+	ti->status &= ~TS_RESTORE_SIGMASK;
+	return true;
 }
 #endif	/* !__ASSEMBLY__ */
 
diff --git a/arch/ia64/kernel/signal.c b/arch/ia64/kernel/signal.c
index 7523501..a199be1 100644
--- a/arch/ia64/kernel/signal.c
+++ b/arch/ia64/kernel/signal.c
@@ -30,7 +30,6 @@
 
 #define DEBUG_SIG	0
 #define STACK_ALIGN	16		/* minimal alignment for stack pointer */
-#define _BLOCKABLE	(~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
 
 #if _NSIG_WORDS > 1
 # define PUT_SIGSET(k,u)	__copy_to_user((u)->sig, (k)->sig, sizeof(sigset_t))
@@ -200,7 +199,6 @@ ia64_rt_sigreturn (struct sigscratch *scr)
 	if (GET_SIGSET(&set, &sc->sc_mask))
 		goto give_sigsegv;
 
-	sigdelsetmask(&set, ~_BLOCKABLE);
 	set_current_blocked(&set);
 
 	if (restore_sigcontext(sc, scr))
@@ -415,18 +413,13 @@ setup_frame (int sig, struct k_sigaction *ka, siginfo_t *info, sigset_t *set,
 }
 
 static long
-handle_signal (unsigned long sig, struct k_sigaction *ka, siginfo_t *info, sigset_t *oldset,
+handle_signal (unsigned long sig, struct k_sigaction *ka, siginfo_t *info,
 	       struct sigscratch *scr)
 {
-	if (!setup_frame(sig, ka, info, oldset, scr))
+	if (!setup_frame(sig, ka, info, sigmask_to_save(), scr))
 		return 0;
 
-	block_sigmask(ka, sig);
-
-	/*
-	 * Let tracing know that we've done the handler setup.
-	 */
-	tracehook_signal_handler(sig, info, ka, &scr->pt,
+	signal_delivered(sig, info, ka, &scr->pt,
 				 test_thread_flag(TIF_SINGLESTEP));
 
 	return 1;
@@ -440,7 +433,6 @@ void
 ia64_do_signal (struct sigscratch *scr, long in_syscall)
 {
 	struct k_sigaction ka;
-	sigset_t *oldset;
 	siginfo_t info;
 	long restart = in_syscall;
 	long errno = scr->pt.r8;
@@ -453,11 +445,6 @@ ia64_do_signal (struct sigscratch *scr, long in_syscall)
 	if (!user_mode(&scr->pt))
 		return;
 
-	if (current_thread_info()->status & TS_RESTORE_SIGMASK)
-		oldset = &current->saved_sigmask;
-	else
-		oldset = &current->blocked;
-
 	/*
 	 * This only loops in the rare cases of handle_signal() failing, in which case we
 	 * need to push through a forced SIGSEGV.
@@ -507,16 +494,8 @@ ia64_do_signal (struct sigscratch *scr, long in_syscall)
 		 * Whee!  Actually deliver the signal.  If the delivery failed, we need to
 		 * continue to iterate in this loop so we can deliver the SIGSEGV...
 		 */
-		if (handle_signal(signr, &ka, &info, oldset, scr)) {
-			/*
-			 * A signal was successfully delivered; the saved
-			 * sigmask will have been stored in the signal frame,
-			 * and will be restored by sigreturn, so we can simply
-			 * clear the TS_RESTORE_SIGMASK flag.
-			 */
-			current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
+		if (handle_signal(signr, &ka, &info, scr))
 			return;
-		}
 	}
 
 	/* Did we come from a system call? */
@@ -538,8 +517,5 @@ ia64_do_signal (struct sigscratch *scr, long in_syscall)
 
 	/* if there's no signal to deliver, we just put the saved sigmask
 	 * back */
-	if (current_thread_info()->status & TS_RESTORE_SIGMASK) {
-		current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
-		sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
-	}
+	restore_saved_sigmask();
 }