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 310d9734f02d..f7ee85378311 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 7523501d3bc0..a199be1fe619 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();
 }