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, 19 insertions, 52 deletions

diff --git a/arch/blackfin/include/asm/thread_info.h b/arch/blackfin/include/asm/thread_info.h
index 02560fd8a12..53ad10005ae 100644
--- a/arch/blackfin/include/asm/thread_info.h
+++ b/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)
diff --git a/arch/blackfin/kernel/signal.c b/arch/blackfin/kernel/signal.c
index fc9ecce8b6c..6682b73a852 100644
--- a/arch/blackfin/kernel/signal.c
+++ b/arch/blackfin/kernel/signal.c
@@ -19,8 +19,6 @@
 #include <asm/fixed_code.h>
 #include <asm/syscall.h>
 
-#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
-
 /* Location of the trace bit in SYSCFG. */
 #define TRACE_BITS 0x0001
 
@@ -98,7 +96,6 @@ asmlinkage int do_rt_sigreturn(unsigned long __unused)
 	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 		goto badframe;
 
-	sigdelsetmask(&set, ~_BLOCKABLE);
 	set_current_blocked(&set);
 
 	if (rt_restore_sigcontext(regs, &frame->uc.uc_mcontext, &r0))
@@ -190,17 +187,22 @@ setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t * info,
 	err |= copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 
 	if (err)
-		goto give_sigsegv;
+		return -EFAULT;
 
 	/* Set up registers for signal handler */
-	wrusp((unsigned long)frame);
 	if (current->personality & FDPIC_FUNCPTRS) {
 		struct fdpic_func_descriptor __user *funcptr =
 			(struct fdpic_func_descriptor *) ka->sa.sa_handler;
-		__get_user(regs->pc, &funcptr->text);
-		__get_user(regs->p3, &funcptr->GOT);
+		u32 pc, p3;
+		err |= __get_user(pc, &funcptr->text);
+		err |= __get_user(p3, &funcptr->GOT);
+		if (err)
+			return -EFAULT;
+		regs->pc = pc;
+		regs->p3 = p3;
 	} else
 		regs->pc = (unsigned long)ka->sa.sa_handler;
+	wrusp((unsigned long)frame);
 	regs->rets = SIGRETURN_STUB;
 
 	regs->r0 = frame->sig;
@@ -208,10 +210,6 @@ setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t * info,
 	regs->r2 = (unsigned long)(&frame->uc);
 
 	return 0;
-
- give_sigsegv:
-	force_sigsegv(sig, current);
-	return -EFAULT;
 }
 
 static inline void
@@ -247,24 +245,21 @@ handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler)
 /*
  * OK, we're invoking a handler
  */
-static int
+static void
 handle_signal(int sig, siginfo_t *info, struct k_sigaction *ka,
-	      sigset_t *oldset, struct pt_regs *regs)
+	      struct pt_regs *regs)
 {
-	int ret;
-
 	/* are we from a system call? to see pt_regs->orig_p0 */
 	if (regs->orig_p0 >= 0)
 		/* If so, check system call restarting.. */
 		handle_restart(regs, ka, 1);
 
 	/* set up the stack frame */
-	ret = setup_rt_frame(sig, ka, info, oldset, regs);
-
-	if (ret == 0)
-		block_sigmask(ka, sig);
-
-	return ret;
+	if (setup_rt_frame(sig, ka, info, sigmask_to_save(), regs) < 0)
+		force_sigsegv(sig, current);
+	else 
+		signal_delivered(sig, info, ka, regs,
+				test_thread_flag(TIF_SINGLESTEP));
 }
 
 /*
@@ -281,37 +276,16 @@ asmlinkage void do_signal(struct pt_regs *regs)
 	siginfo_t info;
 	int signr;
 	struct k_sigaction ka;
-	sigset_t *oldset;
 
 	current->thread.esp0 = (unsigned long)regs;
 
-	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, 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);
-
-			tracehook_signal_handler(signr, &info, &ka, regs,
-				test_thread_flag(TIF_SINGLESTEP));
-		}
-
+		handle_signal(signr, &info, &ka, regs);
 		return;
 	}
 
- no_signal:
 	/* Did we come from a system call? */
 	if (regs->orig_p0 >= 0)
 		/* Restart the system call - no handlers present */
@@ -319,10 +293,7 @@ asmlinkage 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();
 }
 
 /*
@@ -330,7 +301,7 @@ asmlinkage void do_signal(struct pt_regs *regs)
  */
 asmlinkage void do_notify_resume(struct pt_regs *regs)
 {
-	if (test_thread_flag(TIF_SIGPENDING) || test_thread_flag(TIF_RESTORE_SIGMASK))
+	if (test_thread_flag(TIF_SIGPENDING))
 		do_signal(regs);
 
 	if (test_thread_flag(TIF_NOTIFY_RESUME)) {
diff --git a/arch/blackfin/mach-common/entry.S b/arch/blackfin/mach-common/entry.S
index 80aa2535e2c..04c2fbe41a7 100644
--- a/arch/blackfin/mach-common/entry.S
+++ b/arch/blackfin/mach-common/entry.S
@@ -711,8 +711,6 @@ ENTRY(_system_call)
 	jump .Lresume_userspace_1;
 
 .Lsyscall_sigpending:
-	cc = BITTST(r7, TIF_RESTORE_SIGMASK);
-	if cc jump .Lsyscall_do_signals;
 	cc = BITTST(r7, TIF_SIGPENDING);
 	if cc jump .Lsyscall_do_signals;
 	cc = BITTST(r7, TIF_NOTIFY_RESUME);