Moved signal handling and rescheduling from userret() to ast() so that

they aren't in the usual path of execution for syscalls and traps.
The main complication for this is that we have to set flags to control
ast() everywhere that changes the signal mask.

Avoid locking in userret() in most of the remaining cases.

Submitted by:	luoqi (first part only, long ago, reorganized by me)
Reminded by:	dillon

1 files changed, 25 insertions, 3 deletions

diff --git a/sys/kern/kern_sig.c b/sys/kern/kern_sig.c
index bfefd24..6adda1d 100644
--- a/sys/kern/kern_sig.c
+++ b/sys/kern/kern_sig.c
@@ -180,6 +180,25 @@ CURSIG(struct proc *p)
 	return (SIGPENDING(p) ? issignal(p) : 0);
 }
 
+/*
+ * Arrange for ast() to handle unmasked pending signals on return to user
+ * mode.  This must be called whenever a signal is added to p_siglist or
+ * unmasked in p_sigmask.
+ */
+void
+signotify(struct proc *p)
+{
+
+	PROC_LOCK_ASSERT(p, MA_OWNED);
+	mtx_assert(&sched_lock, MA_NOTOWNED);
+	mtx_lock_spin(&sched_lock);
+	if (SIGPENDING(p)) {
+		p->p_sflag |= PS_NEEDSIGCHK;
+		p->p_kse.ke_flags |= KEF_ASTPENDING;	/* XXXKSE */  
+	}
+	mtx_unlock_spin(&sched_lock);
+}
+
 static __inline int
 sigprop(int sig)
 {
@@ -514,6 +533,7 @@ do_sigprocmask(p, how, set, oset, old)
 			break;
 		case SIG_UNBLOCK:
 			SIGSETNAND(p->p_sigmask, *set);
+			signotify(p);
 			break;
 		case SIG_SETMASK:
 			SIG_CANTMASK(*set);
@@ -521,6 +541,7 @@ do_sigprocmask(p, how, set, oset, old)
 				SIGSETLO(p->p_sigmask, *set);
 			else
 				p->p_sigmask = *set;
+			signotify(p);
 			break;
 		default:
 			error = EINVAL;
@@ -753,6 +774,7 @@ osigsetmask(td, uap)
 	PROC_LOCK(p);
 	SIG2OSIG(p->p_sigmask, td->td_retval[0]);
 	SIGSETLO(p->p_sigmask, set);
+	signotify(p);
 	PROC_UNLOCK(p);
 	mtx_unlock(&Giant);
 	return (0);
@@ -805,6 +827,7 @@ sigsuspend(td, uap)
 
 	SIG_CANTMASK(mask);
 	p->p_sigmask = mask;
+	signotify(p);
 	while (msleep((caddr_t) ps, &p->p_mtx, PPAUSE|PCATCH, "pause", 0) == 0)
 		/* void */;
 	PROC_UNLOCK(p);
@@ -840,6 +863,7 @@ osigsuspend(td, uap)
 	OSIG2SIG(uap->mask, mask);
 	SIG_CANTMASK(mask);
 	SIGSETLO(p->p_sigmask, mask);
+	signotify(p);
 	while (msleep((caddr_t) ps, &p->p_mtx, PPAUSE|PCATCH, "opause", 0) == 0)
 		/* void */;
 	PROC_UNLOCK(p);
@@ -1303,6 +1327,7 @@ psignal(p, sig)
 		SIG_CONTSIGMASK(p->p_siglist);
 	}
 	SIGADDSET(p->p_siglist, sig);
+	signotify(p);
 
 	/*
 	 * Defer further processing for signals which are held,
@@ -1475,7 +1500,6 @@ psignal(p, sig)
 #ifdef SMP
 			struct kse *ke;
 			struct thread *td = curthread;
-			signotify(&p->p_kse);  /* XXXKSE */  
 /* we should only deliver to one thread.. but which one? */
 			FOREACH_KSEGRP_IN_PROC(p, kg) {
 				FOREACH_KSE_IN_GROUP(kg, ke) {
@@ -1485,8 +1509,6 @@ psignal(p, sig)
 					forward_signal(ke->ke_thread);
 				}
 			}
-#else
-			signotify(&p->p_kse);  /* XXXKSE */  
 #endif
 		}
 		mtx_unlock_spin(&sched_lock);