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

arch/mips/kernel/signal-common.h

@@ -19,8 +19,6 @@
 #  define DEBUGP(fmt, args...)
 #endif
 
-#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
-
 /*
  * Determine which stack to use..
  */

arch/mips/kernel/signal.c

@@ -339,7 +339,6 @@ asmlinkage void sys_sigreturn(nabi_no_regargs struct pt_regs regs)
 	if (__copy_from_user(&blocked, &frame->sf_mask, sizeof(blocked)))
 		goto badframe;
 
-	sigdelsetmask(&blocked, ~_BLOCKABLE);
 	set_current_blocked(&blocked);
 
 	sig = restore_sigcontext(&regs, &frame->sf_sc);
@@ -375,7 +374,6 @@ asmlinkage void sys_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
 	if (__copy_from_user(&set, &frame->rs_uc.uc_sigmask, sizeof(set)))
 		goto badframe;
 
-	sigdelsetmask(&set, ~_BLOCKABLE);
 	set_current_blocked(&set);
 
 	sig = restore_sigcontext(&regs, &frame->rs_uc.uc_mcontext);
@@ -514,9 +512,10 @@ struct mips_abi mips_abi = {
 	.restart	= __NR_restart_syscall
 };
 
-static int handle_signal(unsigned long sig, siginfo_t *info,
-	struct k_sigaction *ka, sigset_t *oldset, struct pt_regs *regs)
+static void handle_signal(unsigned long sig, siginfo_t *info,
+	struct k_sigaction *ka, struct pt_regs *regs)
 {
+	sigset_t *oldset = sigmask_to_save();
 	int ret;
 	struct mips_abi *abi = current->thread.abi;
 	void *vdso = current->mm->context.vdso;
@@ -550,17 +549,14 @@ static int handle_signal(unsigned long sig, siginfo_t *info,
 				       ka, regs, sig, oldset);
 
 	if (ret)
-		return ret;
+		return;
 
-	block_sigmask(ka, sig);
-
-	return ret;
+	signal_delivered(sig, info, ka, regs, 0);
 }
 
 static void do_signal(struct pt_regs *regs)
 {
 	struct k_sigaction ka;
-	sigset_t *oldset;
 	siginfo_t info;
 	int signr;
 
@@ -572,25 +568,10 @@ static void do_signal(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(signr, &info, &ka, 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, &info, &ka, regs);
 		return;
 	}
 
@@ -614,10 +595,7 @@ static void do_signal(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();
 }
 
 /*
@@ -630,7 +608,7 @@ asmlinkage void do_notify_resume(struct pt_regs *regs, void *unused,
 	local_irq_enable();
 
 	/* deal with pending signal delivery */
-	if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
+	if (thread_info_flags & _TIF_SIGPENDING)
 		do_signal(regs);
 
 	if (thread_info_flags & _TIF_NOTIFY_RESUME) {

arch/mips/kernel/signal32.c

@@ -465,7 +465,6 @@ asmlinkage void sys32_sigreturn(nabi_no_regargs struct pt_regs regs)
 	if (__copy_conv_sigset_from_user(&blocked, &frame->sf_mask))
 		goto badframe;
 
-	sigdelsetmask(&blocked, ~_BLOCKABLE);
 	set_current_blocked(&blocked);
 
 	sig = restore_sigcontext32(&regs, &frame->sf_sc);
@@ -503,7 +502,6 @@ asmlinkage void sys32_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
 	if (__copy_conv_sigset_from_user(&set, &frame->rs_uc.uc_sigmask))
 		goto badframe;
 
-	sigdelsetmask(&set, ~_BLOCKABLE);
 	set_current_blocked(&set);
 
 	sig = restore_sigcontext32(&regs, &frame->rs_uc.uc_mcontext);

arch/mips/kernel/signal_n32.c

@@ -109,7 +109,6 @@ asmlinkage void sysn32_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
 	if (__copy_conv_sigset_from_user(&set, &frame->rs_uc.uc_sigmask))
 		goto badframe;
 
-	sigdelsetmask(&set, ~_BLOCKABLE);
 	set_current_blocked(&set);
 
 	sig = restore_sigcontext(&regs, &frame->rs_uc.uc_mcontext);