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

5 files changed, 37 insertions, 84 deletions

diff --git a/arch/sparc/include/asm/thread_info_32.h b/arch/sparc/include/asm/thread_info_32.h
index 5af664932452..e6cd224506a9 100644
--- a/arch/sparc/include/asm/thread_info_32.h
+++ b/arch/sparc/include/asm/thread_info_32.h
@@ -131,8 +131,7 @@ register struct thread_info *current_thread_info_reg asm("g6");
 #define _TIF_POLLING_NRFLAG     (1<<TIF_POLLING_NRFLAG)
 
 #define _TIF_DO_NOTIFY_RESUME_MASK      (_TIF_NOTIFY_RESUME | \
-                                         _TIF_SIGPENDING | \
-                                         _TIF_RESTORE_SIGMASK)
+                                         _TIF_SIGPENDING)
 
 #endif /* __KERNEL__ */
 
diff --git a/arch/sparc/include/asm/thread_info_64.h b/arch/sparc/include/asm/thread_info_64.h
index 7f0981b09451..cfa8c38fb9c8 100644
--- a/arch/sparc/include/asm/thread_info_64.h
+++ b/arch/sparc/include/asm/thread_info_64.h
@@ -238,7 +238,23 @@ 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/sparc/kernel/signal32.c b/arch/sparc/kernel/signal32.c
index bb1513e45f1a..a53e0a5fd3a3 100644
--- a/arch/sparc/kernel/signal32.c
+++ b/arch/sparc/kernel/signal32.c
@@ -32,8 +32,6 @@
 
 #include "sigutil.h"
 
-#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
-
 /* This magic should be in g_upper[0] for all upper parts
  * to be valid.
  */
@@ -274,7 +272,6 @@ void do_sigreturn32(struct pt_regs *regs)
                 case 2: set.sig[1] = seta[2] + (((long)seta[3]) << 32);
                 case 1: set.sig[0] = seta[0] + (((long)seta[1]) << 32);
         }
-        sigdelsetmask(&set, ~_BLOCKABLE);
         set_current_blocked(&set);
         return;
 
@@ -376,7 +373,6 @@ asmlinkage void do_rt_sigreturn32(struct pt_regs *regs)
                 case 2: set.sig[1] = seta.sig[2] + (((long)seta.sig[3]) << 32);
                 case 1: set.sig[0] = seta.sig[0] + (((long)seta.sig[1]) << 32);
         }
-        sigdelsetmask(&set, ~_BLOCKABLE);
         set_current_blocked(&set);
         return;
 segv:
@@ -775,7 +771,7 @@ sigsegv:
         return -EFAULT;
 }
 
-static inline int handle_signal32(unsigned long signr, struct k_sigaction *ka,
+static inline void handle_signal32(unsigned long signr, struct k_sigaction *ka,
                                   siginfo_t *info,
                                   sigset_t *oldset, struct pt_regs *regs)
 {
@@ -787,12 +783,9 @@ static inline int handle_signal32(unsigned long signr, struct k_sigaction *ka,
                 err = setup_frame32(ka, regs, signr, oldset);
 
         if (err)
-                return err;
-
-        block_sigmask(ka, signr);
-        tracehook_signal_handler(signr, info, ka, regs, 0);
+                return;
 
-        return 0;
+        signal_delivered(signr, info, ka, regs, 0);
 }
 
 static inline void syscall_restart32(unsigned long orig_i0, struct pt_regs *regs,
@@ -841,14 +834,7 @@ void do_signal32(sigset_t *oldset, struct pt_regs * regs)
         if (signr > 0) {
                 if (restart_syscall)
                         syscall_restart32(orig_i0, regs, &ka.sa);
-                if (handle_signal32(signr, &ka, &info, oldset, regs) == 0) {
-                        /* 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;
-                }
+                handle_signal32(signr, &ka, &info, oldset, regs);
                 return;
         }
         if (restart_syscall &&
@@ -872,10 +858,7 @@ void do_signal32(sigset_t *oldset, struct pt_regs * regs)
         /* 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;
-                set_current_blocked(&current->saved_sigmask);
-        }
+        restore_saved_sigmask();
 }
 
 struct sigstack32 {
diff --git a/arch/sparc/kernel/signal_32.c b/arch/sparc/kernel/signal_32.c
index 6b42e8622d12..68f9c8650af4 100644
--- a/arch/sparc/kernel/signal_32.c
+++ b/arch/sparc/kernel/signal_32.c
@@ -29,8 +29,6 @@
 
 #include "sigutil.h"
 
-#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
-
 extern void fpsave(unsigned long *fpregs, unsigned long *fsr,
                    void *fpqueue, unsigned long *fpqdepth);
 extern void fpload(unsigned long *fpregs, unsigned long *fsr);
@@ -130,7 +128,6 @@ asmlinkage void do_sigreturn(struct pt_regs *regs)
         if (err)
                 goto segv_and_exit;
 
-        sigdelsetmask(&set, ~_BLOCKABLE);
         set_current_blocked(&set);
         return;
 
@@ -197,7 +194,6 @@ asmlinkage void do_rt_sigreturn(struct pt_regs *regs)
                         goto segv;
         }
 
-        sigdelsetmask(&set, ~_BLOCKABLE);
         set_current_blocked(&set);
         return;
 segv:
@@ -449,10 +445,11 @@ sigsegv:
         return -EFAULT;
 }
 
-static inline int
+static inline void
 handle_signal(unsigned long signr, struct k_sigaction *ka,
-              siginfo_t *info, sigset_t *oldset, struct pt_regs *regs)
+              siginfo_t *info, struct pt_regs *regs)
 {
+        sigset_t *oldset = sigmask_to_save();
         int err;
 
         if (ka->sa.sa_flags & SA_SIGINFO)
@@ -461,12 +458,9 @@ handle_signal(unsigned long signr, struct k_sigaction *ka,
                 err = setup_frame(ka, regs, signr, oldset);
 
         if (err)
-                return err;
-
-        block_sigmask(ka, signr);
-        tracehook_signal_handler(signr, info, ka, regs, 0);
+                return;
 
-        return 0;
+        signal_delivered(signr, info, ka, regs, 0);
 }
 
 static inline void syscall_restart(unsigned long orig_i0, struct pt_regs *regs,
@@ -498,7 +492,6 @@ static void do_signal(struct pt_regs *regs, unsigned long orig_i0)
 {
         struct k_sigaction ka;
         int restart_syscall;
-        sigset_t *oldset;
         siginfo_t info;
         int signr;
 
@@ -523,11 +516,6 @@ static void do_signal(struct pt_regs *regs, unsigned long orig_i0)
         if (pt_regs_is_syscall(regs) && (regs->psr & PSR_C))
                 regs->u_regs[UREG_G6] = orig_i0;
 
-        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 the debugger messes with the program counter, it clears
@@ -544,15 +532,7 @@ static void do_signal(struct pt_regs *regs, unsigned long orig_i0)
         if (signr > 0) {
                 if (restart_syscall)
                         syscall_restart(orig_i0, regs, &ka.sa);
-                if (handle_signal(signr, &ka, &info, oldset, regs) == 0) {
-                        /* 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(signr, &ka, &info, regs);
                 return;
         }
         if (restart_syscall &&
@@ -576,16 +556,13 @@ static void do_signal(struct pt_regs *regs, unsigned long orig_i0)
         /* 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);
-                set_current_blocked(&current->saved_sigmask);
-        }
+        restore_saved_sigmask();
 }
 
 void do_notify_resume(struct pt_regs *regs, unsigned long orig_i0,
                       unsigned long thread_info_flags)
 {
-        if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
+        if (thread_info_flags & _TIF_SIGPENDING)
                 do_signal(regs, orig_i0);
         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
                 clear_thread_flag(TIF_NOTIFY_RESUME);
diff --git a/arch/sparc/kernel/signal_64.c b/arch/sparc/kernel/signal_64.c
index c82cf1cc3965..867de2f8189c 100644
--- a/arch/sparc/kernel/signal_64.c
+++ b/arch/sparc/kernel/signal_64.c
@@ -38,8 +38,6 @@
 #include "systbls.h"
 #include "sigutil.h"
 
-#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
-
 /* {set, get}context() needed for 64-bit SparcLinux userland. */
 asmlinkage void sparc64_set_context(struct pt_regs *regs)
 {
@@ -71,7 +69,6 @@ asmlinkage void sparc64_set_context(struct pt_regs *regs)
                         if (__copy_from_user(&set, &ucp->uc_sigmask, sizeof(sigset_t)))
                                 goto do_sigsegv;
                 }
-                sigdelsetmask(&set, ~_BLOCKABLE);
                 set_current_blocked(&set);
         }
         if (test_thread_flag(TIF_32BIT)) {
@@ -315,7 +312,6 @@ void do_rt_sigreturn(struct pt_regs *regs)
         /* Prevent syscall restart.  */
         pt_regs_clear_syscall(regs);
 
-        sigdelsetmask(&set, ~_BLOCKABLE);
         set_current_blocked(&set);
         return;
 segv:
@@ -466,7 +462,7 @@ sigsegv:
         return -EFAULT;
 }
 
-static inline int handle_signal(unsigned long signr, struct k_sigaction *ka,
+static inline void handle_signal(unsigned long signr, struct k_sigaction *ka,
                                 siginfo_t *info,
                                 sigset_t *oldset, struct pt_regs *regs)
 {
@@ -475,12 +471,9 @@ static inline int handle_signal(unsigned long signr, struct k_sigaction *ka,
         err = setup_rt_frame(ka, regs, signr, oldset,
                              (ka->sa.sa_flags & SA_SIGINFO) ? info : NULL);
         if (err)
-                return err;
-
-        block_sigmask(ka, signr);
-        tracehook_signal_handler(signr, info, ka, regs, 0);
+                return;
 
-        return 0;
+        signal_delivered(signr, info, ka, regs, 0);
 }
 
 static inline void syscall_restart(unsigned long orig_i0, struct pt_regs *regs,
@@ -512,7 +505,7 @@ static void do_signal(struct pt_regs *regs, unsigned long orig_i0)
 {
         struct k_sigaction ka;
         int restart_syscall;
-        sigset_t *oldset;
+        sigset_t *oldset = sigmask_to_save();
         siginfo_t info;
         int signr;
         
@@ -538,11 +531,6 @@ static void do_signal(struct pt_regs *regs, unsigned long orig_i0)
             (regs->tstate & (TSTATE_XCARRY | TSTATE_ICARRY)))
                 regs->u_regs[UREG_G6] = orig_i0;
 
-        if (current_thread_info()->status & TS_RESTORE_SIGMASK)
-                oldset = &current->saved_sigmask;
-        else
-                oldset = &current->blocked;
-
 #ifdef CONFIG_COMPAT
         if (test_thread_flag(TIF_32BIT)) {
                 extern void do_signal32(sigset_t *, struct pt_regs *);
@@ -563,14 +551,7 @@ static void do_signal(struct pt_regs *regs, unsigned long orig_i0)
         if (signr > 0) {
                 if (restart_syscall)
                         syscall_restart(orig_i0, regs, &ka.sa);
-                if (handle_signal(signr, &ka, &info, oldset, regs) == 0) {
-                        /* 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;
-                }
+                handle_signal(signr, &ka, &info, oldset, regs);
                 return;
         }
         if (restart_syscall &&
@@ -594,10 +575,7 @@ static void do_signal(struct pt_regs *regs, unsigned long orig_i0)
         /* 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;
-                set_current_blocked(&current->saved_sigmask);
-        }
+        restore_saved_sigmask();
 }
 
 void do_notify_resume(struct pt_regs *regs, unsigned long orig_i0, unsigned long thread_info_flags)