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 54ab13a0de4..0ff03a33c81 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 5ba23f715ea..7d5e000fd32 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 595bf1e5a5d..f3b9064c548 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 */