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

3 files changed, 35 insertions, 67 deletions

diff --git a/arch/frv/include/asm/thread_info.h b/arch/frv/include/asm/thread_info.h
index 54ab13a0de41..0ff03a33c81e 100644
--- a/arch/frv/include/asm/thread_info.h
+++ b/arch/frv/include/asm/thread_info.h
@@ -94,8 +94,8 @@ register struct thread_info *__current_thread_info asm("gr15");
 #define TIF_NEED_RESCHED        3       /* rescheduling necessary */
 #define TIF_SINGLESTEP          4       /* restore singlestep on return to user mode */
 #define TIF_RESTORE_SIGMASK     5       /* restore signal mask in do_signal() */
-#define TIF_POLLING_NRFLAG      16      /* true if poll_idle() is polling TIF_NEED_RESCHED */
-#define TIF_MEMDIE              17      /* is terminating due to OOM killer */
+#define TIF_POLLING_NRFLAG      6       /* true if poll_idle() is polling TIF_NEED_RESCHED */
+#define TIF_MEMDIE              7       /* is terminating due to OOM killer */
 
 #define _TIF_SYSCALL_TRACE      (1 << TIF_SYSCALL_TRACE)
 #define _TIF_NOTIFY_RESUME      (1 << TIF_NOTIFY_RESUME)
@@ -105,8 +105,16 @@ register struct thread_info *__current_thread_info asm("gr15");
 #define _TIF_RESTORE_SIGMASK    (1 << TIF_RESTORE_SIGMASK)
 #define _TIF_POLLING_NRFLAG     (1 << TIF_POLLING_NRFLAG)
 
-#define _TIF_WORK_MASK          0x0000FFFE      /* work to do on interrupt/exception return */
-#define _TIF_ALLWORK_MASK       0x0000FFFF      /* work to do on any return to u-space */
+/* work to do on interrupt/exception return */
+#define _TIF_WORK_MASK          \
+        (_TIF_NOTIFY_RESUME | _TIF_SIGPENDING | _TIF_NEED_RESCHED | _TIF_SINGLESTEP)
+
+/* work to do on any return to u-space */
+#define _TIF_ALLWORK_MASK       (_TIF_WORK_MASK | _TIF_SYSCALL_TRACE)
+
+#if _TIF_ALLWORK_MASK >= 0x2000
+#error "_TIF_ALLWORK_MASK won't fit in an ANDI now (see entry.S)"
+#endif
 
 /*
  * Thread-synchronous status.
diff --git a/arch/frv/kernel/entry.S b/arch/frv/kernel/entry.S
index 5ba23f715ea5..7d5e000fd32e 100644
--- a/arch/frv/kernel/entry.S
+++ b/arch/frv/kernel/entry.S
@@ -905,18 +905,19 @@ __syscall_call:
 __syscall_exit:
         LEDS            0x6300
 
-        sti             gr8,@(gr28,#REG_GR(8))  ; save return value
+        # keep current PSR in GR23
+        movsg           psr,gr23
 
-        # rebuild saved psr - execve will change it for init/main.c
         ldi             @(gr28,#REG_PSR),gr22
+
+        sti.p           gr8,@(gr28,#REG_GR(8))  ; save return value
+
+        # rebuild saved psr - execve will change it for init/main.c
         srli            gr22,#1,gr5
         andi.p          gr22,#~PSR_PS,gr22
         andi            gr5,#PSR_PS,gr5
         or              gr5,gr22,gr22
-        ori             gr22,#PSR_S,gr22
-
-        # keep current PSR in GR23
-        movsg           psr,gr23
+        ori.p           gr22,#PSR_S,gr22
 
         # make sure we don't miss an interrupt setting need_resched or sigpending between
         # sampling and the RETT
@@ -924,9 +925,7 @@ __syscall_exit:
         movgs           gr23,psr
 
         ldi             @(gr15,#TI_FLAGS),gr4
-        sethi.p         %hi(_TIF_ALLWORK_MASK),gr5
-        setlo           %lo(_TIF_ALLWORK_MASK),gr5
-        andcc           gr4,gr5,gr0,icc0
+        andicc          gr4,#_TIF_ALLWORK_MASK,gr0,icc0
         bne             icc0,#0,__syscall_exit_work
 
         # restore all registers and return
@@ -1111,9 +1110,7 @@ __entry_resume_userspace:
 __entry_return_from_user_interrupt:
         LEDS            0x6402
         ldi             @(gr15,#TI_FLAGS),gr4
-        sethi.p         %hi(_TIF_WORK_MASK),gr5
-        setlo           %lo(_TIF_WORK_MASK),gr5
-        andcc           gr4,gr5,gr0,icc0
+        andicc          gr4,#_TIF_WORK_MASK,gr0,icc0
         beq             icc0,#1,__entry_return_direct
 
 __entry_work_pending:
@@ -1133,9 +1130,7 @@ __entry_work_resched:
 
         LEDS            0x6401
         ldi             @(gr15,#TI_FLAGS),gr4
-        sethi.p         %hi(_TIF_WORK_MASK),gr5
-        setlo           %lo(_TIF_WORK_MASK),gr5
-        andcc           gr4,gr5,gr0,icc0
+        andicc          gr4,#_TIF_WORK_MASK,gr0,icc0
         beq             icc0,#1,__entry_return_direct
         andicc          gr4,#_TIF_NEED_RESCHED,gr0,icc0
         bne             icc0,#1,__entry_work_resched
@@ -1163,7 +1158,9 @@ __syscall_trace_entry:
         # perform syscall exit tracing
 __syscall_exit_work:
         LEDS            0x6340
-        andicc          gr4,#_TIF_SYSCALL_TRACE,gr0,icc0
+        andicc          gr22,#PSR_PS,gr0,icc1   ; don't handle on return to kernel mode
+        andicc.p        gr4,#_TIF_SYSCALL_TRACE,gr0,icc0
+        bne             icc1,#0,__entry_return_direct
         beq             icc0,#1,__entry_work_pending
 
         movsg           psr,gr23
diff --git a/arch/frv/kernel/signal.c b/arch/frv/kernel/signal.c
index 595bf1e5a5dc..f3b9064c548c 100644
--- a/arch/frv/kernel/signal.c
+++ b/arch/frv/kernel/signal.c
@@ -28,8 +28,6 @@
 
 #define DEBUG_SIG 0
 
-#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
-
 struct fdpic_func_descriptor {
         unsigned long   text;
         unsigned long   GOT;
@@ -149,7 +147,6 @@ asmlinkage int sys_sigreturn(void)
             __copy_from_user(&set.sig[1], &frame->extramask, sizeof(frame->extramask)))
                 goto badframe;
 
-        sigdelsetmask(&set, ~_BLOCKABLE);
         set_current_blocked(&set);
 
         if (restore_sigcontext(&frame->sc, &gr8))
@@ -172,7 +169,6 @@ asmlinkage int sys_rt_sigreturn(void)
         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
                 goto badframe;
 
-        sigdelsetmask(&set, ~_BLOCKABLE);
         set_current_blocked(&set);
 
         if (restore_sigcontext(&frame->uc.uc_mcontext, &gr8))
@@ -426,9 +422,10 @@ give_sigsegv:
 /*
  * OK, we're invoking a handler
  */
-static int handle_signal(unsigned long sig, siginfo_t *info,
-                         struct k_sigaction *ka, sigset_t *oldset)
+static void handle_signal(unsigned long sig, siginfo_t *info,
+                         struct k_sigaction *ka)
 {
+        sigset_t *oldset = sigmask_to_save();
         int ret;
 
         /* Are we from a system call? */
@@ -460,11 +457,11 @@ static int handle_signal(unsigned long sig, siginfo_t *info,
         else
                 ret = setup_frame(sig, ka, oldset);
 
-        if (ret == 0)
-                block_sigmask(ka, sig);
-
-        return ret;
+        if (ret)
+                return;
 
+        signal_delivered(sig, info, ka, __frame,
+                                 test_thread_flag(TIF_SINGLESTEP));
 } /* end handle_signal() */
 
 /*****************************************************************************/
@@ -477,44 +474,14 @@ static void do_signal(void)
 {
         struct k_sigaction ka;
         siginfo_t info;
-        sigset_t *oldset;
         int signr;
 
-        /*
-         * We want the common case to go fast, which
-         * is why we may in certain cases get here from
-         * kernel mode. Just return without doing anything
-         * if so.
-         */
-        if (!user_mode(__frame))
-                return;
-
-        if (try_to_freeze())
-                goto no_signal;
-
-        if (test_thread_flag(TIF_RESTORE_SIGMASK))
-                oldset = &current->saved_sigmask;
-        else
-                oldset = &current->blocked;
-
         signr = get_signal_to_deliver(&info, &ka, __frame, NULL);
         if (signr > 0) {
-                if (handle_signal(signr, &info, &ka, oldset) == 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);
-
-                        tracehook_signal_handler(signr, &info, &ka, __frame,
-                                                 test_thread_flag(TIF_SINGLESTEP));
-                }
-
+                handle_signal(signr, &info, &ka);
                 return;
         }
 
-no_signal:
         /* Did we come from a system call? */
         if (__frame->syscallno != -1) {
                 /* Restart the system call - no handlers present */
@@ -536,11 +503,7 @@ no_signal:
 
         /* 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();
 } /* end do_signal() */
 
 /*****************************************************************************/
@@ -555,7 +518,7 @@ asmlinkage void do_notify_resume(__u32 thread_info_flags)
                 clear_thread_flag(TIF_SINGLESTEP);
 
         /* deal with pending signal delivery */
-        if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
+        if (thread_info_flags & _TIF_SIGPENDING))
                 do_signal();
 
         /* deal with notification on about to resume userspace execution */