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

Author: torvalds

arch/alpha/kernel/signal.c

@@ -226,7 +226,6 @@ do_sigreturn(struct sigcontext __user *sc, struct pt_regs *regs,
 	if (__get_user(set.sig[0], &sc->sc_mask))
 		goto give_sigsegv;
 
-	sigdelsetmask(&set, ~_BLOCKABLE);
 	set_current_blocked(&set);
 
 	if (restore_sigcontext(sc, regs, sw))
@@ -261,7 +260,6 @@ do_rt_sigreturn(struct rt_sigframe __user *frame, struct pt_regs *regs,
 	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 		goto give_sigsegv;
 
-	sigdelsetmask(&set, ~_BLOCKABLE);
 	set_current_blocked(&set);
 
 	if (restore_sigcontext(&frame->uc.uc_mcontext, regs, sw))
@@ -468,12 +466,9 @@ static inline void
 handle_signal(int sig, struct k_sigaction *ka, siginfo_t *info,
 	      struct pt_regs * regs, struct switch_stack *sw)
 {
-	sigset_t *oldset = &current->blocked;
+	sigset_t *oldset = sigmask_to_save();
 	int ret;
 
-	if (test_thread_flag(TIF_RESTORE_SIGMASK))
-		oldset = &current->saved_sigmask;
-
 	if (ka->sa.sa_flags & SA_SIGINFO)
 		ret = setup_rt_frame(sig, ka, info, oldset, regs, sw);
 	else
@@ -483,12 +478,7 @@ handle_signal(int sig, struct k_sigaction *ka, siginfo_t *info,
 		force_sigsegv(sig, current);
 		return;
 	}
-	block_sigmask(ka, sig);
-	/* A signal was successfully delivered, and the
-	   saved sigmask was stored on the signal frame,
-	   and will be restored by sigreturn.  So we can
-	   simply clear the restore sigmask flag.  */
-	clear_thread_flag(TIF_RESTORE_SIGMASK);
+	signal_delivered(sig, info, ka, regs, 0);
 }
 
 static inline void
@@ -572,9 +562,7 @@ do_signal(struct pt_regs * regs, struct switch_stack * sw,
 	}
 
 	/* If there's no signal to deliver, we just restore the saved mask.  */
-	if (test_and_clear_thread_flag(TIF_RESTORE_SIGMASK))
-		set_current_blocked(&current->saved_sigmask);
-
+	restore_saved_sigmask();
 	if (single_stepping)
 		ptrace_set_bpt(current);	/* re-set breakpoint */
 }

arch/arm/kernel/signal.c

@@ -22,8 +22,6 @@
 
 #include "signal.h"
 
-#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
-
 /*
  * For ARM syscalls, we encode the syscall number into the instruction.
  */
@@ -210,10 +208,8 @@ static int restore_sigframe(struct pt_regs *regs, struct sigframe __user *sf)
 	int err;
 
 	err = __copy_from_user(&set, &sf->uc.uc_sigmask, sizeof(set));
-	if (err == 0) {
-		sigdelsetmask(&set, ~_BLOCKABLE);
+	if (err == 0)
 		set_current_blocked(&set);
-	}
 
 	__get_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err);
 	__get_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err);
@@ -528,13 +524,13 @@ setup_rt_frame(int usig, struct k_sigaction *ka, siginfo_t *info,
 /*
  * OK, we're invoking a handler
  */	
-static int
+static void
 handle_signal(unsigned long sig, struct k_sigaction *ka,
-	      siginfo_t *info, sigset_t *oldset,
-	      struct pt_regs * regs)
+	      siginfo_t *info, struct pt_regs *regs)
 {
 	struct thread_info *thread = current_thread_info();
 	struct task_struct *tsk = current;
+	sigset_t *oldset = sigmask_to_save();
 	int usig = sig;
 	int ret;
 
@@ -559,17 +555,9 @@ handle_signal(unsigned long sig, struct k_sigaction *ka,
 
 	if (ret != 0) {
 		force_sigsegv(sig, tsk);
-		return ret;
+		return;
 	}
-
-	/*
-	 * Block the signal if we were successful.
-	 */
-	block_sigmask(ka, sig);
-
-	tracehook_signal_handler(sig, info, ka, regs, 0);
-
-	return 0;
+	signal_delivered(sig, info, ka, regs, 0);
 }
 
 /*
@@ -617,8 +605,6 @@ static void do_signal(struct pt_regs *regs, int syscall)
 	 */
 	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 	if (signr > 0) {
-		sigset_t *oldset;
-
 		/*
 		 * Depending on the signal settings we may need to revert the
 		 * decision to restart the system call.  But skip this if a
@@ -635,20 +621,7 @@ static void do_signal(struct pt_regs *regs, int syscall)
 			clear_thread_flag(TIF_SYSCALL_RESTARTSYS);
 		}
 
-		if (test_thread_flag(TIF_RESTORE_SIGMASK))
-			oldset = &current->saved_sigmask;
-		else
-			oldset = &current->blocked;
-		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;
 	}
 
@@ -663,11 +636,7 @@ static void do_signal(struct pt_regs *regs, int syscall)
 			set_thread_flag(TIF_SYSCALL_RESTARTSYS);
 	}
 
-	/* If there's no signal to deliver, we just put the saved sigmask
-	 * back.
-	 */
-	if (test_and_clear_thread_flag(TIF_RESTORE_SIGMASK))
-		set_current_blocked(&current->saved_sigmask);
+	restore_saved_sigmask();
 }
 
 asmlinkage void

arch/avr32/kernel/entry-avr32b.S

@@ -281,7 +281,7 @@ syscall_exit_work:
 	ld.w	r1, r0[TI_flags]
 	rjmp	1b
 
-2:	mov	r2, _TIF_SIGPENDING | _TIF_RESTORE_SIGMASK | _TIF_NOTIFY_RESUME
+2:	mov	r2, _TIF_SIGPENDING | _TIF_NOTIFY_RESUME
 	tst	r1, r2
 	breq	3f
 	unmask_interrupts
@@ -587,7 +587,7 @@ fault_exit_work:
 	ld.w	r1, r0[TI_flags]
 	rjmp	fault_exit_work
 
-1:	mov	r2, _TIF_SIGPENDING | _TIF_RESTORE_SIGMASK | _TIF_NOTIFY_RESUME
+1:	mov	r2, _TIF_SIGPENDING | _TIF_NOTIFY_RESUME
 	tst	r1, r2
 	breq	2f
 	unmask_interrupts

arch/avr32/kernel/signal.c

@@ -22,8 +22,6 @@
 #include <asm/ucontext.h>
 #include <asm/syscalls.h>
 
-#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
-
 asmlinkage int sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
 			       struct pt_regs *regs)
 {
@@ -89,7 +87,6 @@ asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
 	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))
@@ -224,38 +221,35 @@ static inline void setup_syscall_restart(struct pt_regs *regs)
 
 static inline void
 handle_signal(unsigned long sig, struct k_sigaction *ka, siginfo_t *info,
-	      sigset_t *oldset, struct pt_regs *regs, int syscall)
+	      struct pt_regs *regs, int syscall)
 {
 	int ret;
 
 	/*
 	 * Set up the stack frame
 	 */
-	ret = setup_rt_frame(sig, ka, info, oldset, regs);
+	ret = setup_rt_frame(sig, ka, info, sigmask_to_save(), regs);
 
 	/*
 	 * Check that the resulting registers are sane
 	 */
 	ret |= !valid_user_regs(regs);
 
-	if (ret != 0) {
-		force_sigsegv(sig, current);
-		return;
-	}
-
 	/*
 	 * Block the signal if we were successful.
 	 */
-	block_sigmask(ka, sig);
-	clear_thread_flag(TIF_RESTORE_SIGMASK);
+	if (ret != 0)
+		force_sigsegv(sig, current);
+	else
+		signal_delivered(sig, info, ka, regs, 0);
 }
 
 /*
  * Note that 'init' is a special process: it doesn't get signals it
  * doesn't want to handle. Thus you cannot kill init even with a
  * SIGKILL even by mistake.
  */
-int do_signal(struct pt_regs *regs, sigset_t *oldset, int syscall)
+static void do_signal(struct pt_regs *regs, int syscall)
 {
 	siginfo_t info;
 	int signr;
@@ -267,12 +261,7 @@ int do_signal(struct pt_regs *regs, sigset_t *oldset, int syscall)
 	 * without doing anything if so.
 	 */
 	if (!user_mode(regs))
-		return 0;
-
-	if (test_thread_flag(TIF_RESTORE_SIGMASK))
-		oldset = &current->saved_sigmask;
-	else if (!oldset)
-		oldset = &current->blocked;
+		return;
 
 	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 	if (syscall) {
@@ -297,15 +286,11 @@ int do_signal(struct pt_regs *regs, sigset_t *oldset, int syscall)
 
 	if (signr == 0) {
 		/* No signal to deliver -- 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);
-		}
-		return 0;
+		restore_saved_sigmask();
+		return;
 	}
 
-	handle_signal(signr, &ka, &info, oldset, regs, syscall);
-	return 1;
+	handle_signal(signr, &ka, &info, regs, syscall);
 }
 
 asmlinkage void do_notify_resume(struct pt_regs *regs, struct thread_info *ti)
@@ -315,8 +300,8 @@ asmlinkage void do_notify_resume(struct pt_regs *regs, struct thread_info *ti)
 	if ((sysreg_read(SR) & MODE_MASK) == MODE_SUPERVISOR)
 		syscall = 1;
 
-	if (ti->flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
-		do_signal(regs, &current->blocked, syscall);
+	if (ti->flags & _TIF_SIGPENDING))
+		do_signal(regs, syscall);
 
 	if (ti->flags & _TIF_NOTIFY_RESUME) {
 		clear_thread_flag(TIF_NOTIFY_RESUME);

arch/blackfin/include/asm/thread_info.h

@@ -100,7 +100,6 @@ static inline struct thread_info *current_thread_info(void)
 					   TIF_NEED_RESCHED */
 #define TIF_MEMDIE		4	/* is terminating due to OOM killer */
 #define TIF_RESTORE_SIGMASK	5	/* restore signal mask in do_signal() */
-#define TIF_FREEZE		6	/* is freezing for suspend */
 #define TIF_IRQ_SYNC		7	/* sync pipeline stage */
 #define TIF_NOTIFY_RESUME	8	/* callback before returning to user */
 #define TIF_SINGLESTEP		9
@@ -111,7 +110,6 @@ static inline struct thread_info *current_thread_info(void)
 #define _TIF_NEED_RESCHED	(1<<TIF_NEED_RESCHED)
 #define _TIF_POLLING_NRFLAG	(1<<TIF_POLLING_NRFLAG)
 #define _TIF_RESTORE_SIGMASK	(1<<TIF_RESTORE_SIGMASK)
-#define _TIF_FREEZE		(1<<TIF_FREEZE)
 #define _TIF_IRQ_SYNC		(1<<TIF_IRQ_SYNC)
 #define _TIF_NOTIFY_RESUME	(1<<TIF_NOTIFY_RESUME)
 #define _TIF_SINGLESTEP		(1<<TIF_SINGLESTEP)