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, 12 insertions, 58 deletions

diff --git a/arch/cris/arch-v10/kernel/signal.c b/arch/cris/arch-v10/kernel/signal.c
index e16f8f297f61..0bb477c13a4e 100644
--- a/arch/cris/arch-v10/kernel/signal.c
+++ b/arch/cris/arch-v10/kernel/signal.c
@@ -31,8 +31,6 @@
 
 #define DEBUG_SIG 0
 
-#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
-
 /* a syscall in Linux/CRIS is a break 13 instruction which is 2 bytes */
 /* manipulate regs so that upon return, it will be re-executed */
 
@@ -176,7 +174,6 @@ asmlinkage int sys_sigreturn(long r10, long r11, long r12, long r13, long mof,
                                     sizeof(frame->extramask))))
                 goto badframe;
 
-        sigdelsetmask(&set, ~_BLOCKABLE);
         set_current_blocked(&set);
 
         if (restore_sigcontext(regs, &frame->sc))
@@ -212,7 +209,6 @@ asmlinkage int sys_rt_sigreturn(long r10, long r11, long r12, long r13,
         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
                 goto badframe;
 
-        sigdelsetmask(&set, ~_BLOCKABLE);
         set_current_blocked(&set);
 
         if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
@@ -415,10 +411,11 @@ give_sigsegv:
  * OK, we're invoking a handler
  */
 
-static inline int handle_signal(int canrestart, unsigned long sig,
+static inline void handle_signal(int canrestart, unsigned long sig,
         siginfo_t *info, struct k_sigaction *ka,
-        sigset_t *oldset, struct pt_regs *regs)
+        struct pt_regs *regs)
 {
+        sigset_t *oldset = sigmask_to_save();
         int ret;
 
         /* Are we from a system call? */
@@ -456,9 +453,7 @@ static inline int handle_signal(int canrestart, unsigned long sig,
                 ret = setup_frame(sig, ka, oldset, regs);
 
         if (ret == 0)
-                block_sigmask(ka, sig);
-
-        return ret;
+                signal_delivered(sig, info, ka, regs, 0);
 }
 
 /*
@@ -478,7 +473,6 @@ void do_signal(int canrestart, struct pt_regs *regs)
         siginfo_t info;
         int signr;
         struct k_sigaction ka;
-        sigset_t *oldset;
 
         /*
          * We want the common case to go fast, which
@@ -489,23 +483,10 @@ void do_signal(int canrestart, struct pt_regs *regs)
         if (!user_mode(regs))
                 return;
 
-        if (test_thread_flag(TIF_RESTORE_SIGMASK))
-                oldset = &current->saved_sigmask;
-        else
-                oldset = &current->blocked;
-
         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
         if (signr > 0) {
                 /* Whee!  Actually deliver the signal.  */
-                if (handle_signal(canrestart, signr, &info, &ka,
-                                oldset, regs)) {
-                        /* 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 TIF_RESTORE_SIGMASK flag */
-                        if (test_thread_flag(TIF_RESTORE_SIGMASK))
-                                clear_thread_flag(TIF_RESTORE_SIGMASK);
-                }
+                handle_signal(canrestart, signr, &info, &ka, regs);
                 return;
         }
 
@@ -525,8 +506,5 @@ void do_signal(int canrestart, struct pt_regs *regs)
 
         /* if there's no signal to deliver, we just put the saved sigmask
          * back */
-        if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
-                clear_thread_flag(TIF_RESTORE_SIGMASK);
-                sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
-        }
+        restore_saved_sigmask();
 }
diff --git a/arch/cris/arch-v32/kernel/signal.c b/arch/cris/arch-v32/kernel/signal.c
index b338d8fc0c12..b60d1b65a426 100644
--- a/arch/cris/arch-v32/kernel/signal.c
+++ b/arch/cris/arch-v32/kernel/signal.c
@@ -24,9 +24,6 @@
 
 extern unsigned long cris_signal_return_page;
 
-/* Flag to check if a signal is blockable. */
-#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
-
 /*
  * A syscall in CRIS is really a "break 13" instruction, which is 2
  * bytes. The registers is manipulated so upon return the instruction
@@ -167,7 +164,6 @@ sys_sigreturn(long r10, long r11, long r12, long r13, long mof, long srp,
                                                  sizeof(frame->extramask))))
                 goto badframe;
 
-        sigdelsetmask(&set, ~_BLOCKABLE);
         set_current_blocked(&set);
 
         if (restore_sigcontext(regs, &frame->sc))
@@ -208,7 +204,6 @@ sys_rt_sigreturn(long r10, long r11, long r12, long r13, long mof, long srp,
         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
                 goto badframe;
 
-        sigdelsetmask(&set, ~_BLOCKABLE);
         set_current_blocked(&set);
 
         if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
@@ -434,11 +429,12 @@ give_sigsegv:
 }
 
 /* Invoke a signal handler to, well, handle the signal. */
-static inline int
+static inline void
 handle_signal(int canrestart, unsigned long sig,
               siginfo_t *info, struct k_sigaction *ka,
-              sigset_t *oldset, struct pt_regs * regs)
+              struct pt_regs * regs)
 {
+        sigset_t *oldset = sigmask_to_save();
         int ret;
 
         /* Check if this got called from a system call. */
@@ -489,9 +485,7 @@ handle_signal(int canrestart, unsigned long sig,
                 ret = setup_frame(sig, ka, oldset, regs);
 
         if (ret == 0)
-                block_sigmask(ka, sig);
-
-        return ret;
+                signal_delivered(sig, info, ka, regs, 0);
 }
 
 /*
@@ -511,7 +505,6 @@ do_signal(int canrestart, struct pt_regs *regs)
         int signr;
         siginfo_t info;
         struct k_sigaction ka;
-        sigset_t *oldset;
 
         /*
          * The common case should go fast, which is why this point is
@@ -521,25 +514,11 @@ do_signal(int canrestart, struct pt_regs *regs)
         if (!user_mode(regs))
                 return;
 
-        if (test_thread_flag(TIF_RESTORE_SIGMASK))
-                oldset = &current->saved_sigmask;
-        else
-                oldset = &current->blocked;
-
         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 
         if (signr > 0) {
                 /* Whee!  Actually deliver the signal.  */
-                if (handle_signal(canrestart, signr, &info, &ka,
-                                oldset, regs)) {
-                        /* 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 TIF_RESTORE_SIGMASK flag */
-                        if (test_thread_flag(TIF_RESTORE_SIGMASK))
-                                clear_thread_flag(TIF_RESTORE_SIGMASK);
-                }
-
+                handle_signal(canrestart, signr, &info, &ka, regs);
                 return;
         }
 
@@ -560,10 +539,7 @@ do_signal(int canrestart, struct pt_regs *regs)
 
         /* if there's no signal to deliver, we just put the saved sigmask
          * back */
-        if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
-                clear_thread_flag(TIF_RESTORE_SIGMASK);
-                sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
-        }
+        restore_saved_sigmask();
 }
 
 asmlinkage void