Implement functions to take away the secondary CPUs from the scheduler and

give them back again, effectively stopping and starting these CPUs.  Use
the stop function in sys_reboot().

ok marco@, deraadt@

3 files changed, 62 insertions, 26 deletions

diff --git a/sys/kern/kern_sched.c b/sys/kern/kern_sched.c
index 7625440b7ee..1b58a16a367 100644
--- a/sys/kern/kern_sched.c
+++ b/sys/kern/kern_sched.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_sched.c,v 1.17 2010/01/09 02:44:17 kettenis Exp $	*/
+/*	$OpenBSD: kern_sched.c,v 1.18 2010/04/06 20:33:28 kettenis Exp $	*/
 /*
  * Copyright (c) 2007, 2008 Artur Grabowski <art@openbsd.org>
  *
@@ -32,7 +32,6 @@
 
 
 void sched_kthreads_create(void *);
-void sched_idle(void *);
 
 int sched_proc_to_cpu_cost(struct cpu_info *ci, struct proc *p);
 struct proc *sched_steal_proc(struct cpu_info *);
@@ -546,6 +545,56 @@ sched_peg_curproc(struct cpu_info *ci)
 	SCHED_UNLOCK(s);
 }
 
+#ifdef MULTIPROCESSOR
+
+void
+sched_start_secondary_cpus(void)
+{
+	CPU_INFO_ITERATOR cii;
+	struct cpu_info *ci;
+
+	CPU_INFO_FOREACH(cii, ci) {
+		struct schedstate_percpu *spc = &ci->ci_schedstate;
+
+		if (CPU_IS_PRIMARY(ci))
+			continue;
+		atomic_clearbits_int(&spc->spc_schedflags,
+		    SPCF_SHOULDHALT | SPCF_HALTED);
+	}
+}
+
+void
+sched_stop_secondary_cpus(void)
+{
+	CPU_INFO_ITERATOR cii;
+	struct cpu_info *ci;
+
+	/*
+	 * Make sure we stop the secondary CPUs.
+	 */
+	CPU_INFO_FOREACH(cii, ci) {
+		struct schedstate_percpu *spc = &ci->ci_schedstate;
+
+		if (CPU_IS_PRIMARY(ci))
+			continue;
+		atomic_setbits_int(&spc->spc_schedflags, SPCF_SHOULDHALT);
+	}
+	CPU_INFO_FOREACH(cii, ci) {
+		struct schedstate_percpu *spc = &ci->ci_schedstate;
+		struct sleep_state sls;
+
+		if (CPU_IS_PRIMARY(ci))
+			continue;
+		while ((spc->spc_schedflags & SPCF_HALTED) == 0) {
+			sleep_setup(&sls, spc, PZERO, "schedstate");
+			sleep_finish(&sls,
+			    (spc->spc_schedflags & SPCF_HALTED) == 0);
+		}
+	}
+}
+
+#endif
+
 /*
  * Functions to manipulate cpu sets.
  */
diff --git a/sys/kern/kern_xxx.c b/sys/kern/kern_xxx.c
index 359c97541f2..abe7c4be0df 100644
--- a/sys/kern/kern_xxx.c
+++ b/sys/kern/kern_xxx.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_xxx.c,v 1.15 2010/01/09 02:44:17 kettenis Exp $	*/
+/*	$OpenBSD: kern_xxx.c,v 1.16 2010/04/06 20:33:28 kettenis Exp $	*/
 /*	$NetBSD: kern_xxx.c,v 1.32 1996/04/22 01:38:41 christos Exp $	*/
 
 /*
@@ -68,28 +68,9 @@ sys_reboot(struct proc *p, void *v, register_t *retval)
 		}
 	}
 
-	/*
-	 * Make sure we stop the secondary CPUs.
-	 */
-	CPU_INFO_FOREACH(cii, ci) {
-		struct schedstate_percpu *spc = &ci->ci_schedstate;
-
-		if (CPU_IS_PRIMARY(ci))
-			continue;
-		atomic_setbits_int(&spc->spc_schedflags, SPCF_SHOULDHALT);
-	}
-	CPU_INFO_FOREACH(cii, ci) {
-		struct schedstate_percpu *spc = &ci->ci_schedstate;
-		struct sleep_state sls;
-
-		if (CPU_IS_PRIMARY(ci))
-			continue;
-		while ((spc->spc_schedflags & SPCF_HALTED) == 0) {
-			sleep_setup(&sls, spc, PZERO, "schedstate");
-			sleep_finish(&sls,
-			    (spc->spc_schedflags & SPCF_HALTED) == 0);
-		}
-	}
+#ifdef MULTIPROCESSOR
+	sched_stop_secondary_cpus();
+#endif
 
 	if_downall();
 
diff --git a/sys/sys/sched.h b/sys/sys/sched.h
index 9304a631628..9f2a9d3e1be 100644
--- a/sys/sys/sched.h
+++ b/sys/sys/sched.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: sched.h,v 1.25 2010/01/09 02:44:17 kettenis Exp $	*/
+/*	$OpenBSD: sched.h,v 1.26 2010/04/06 20:33:28 kettenis Exp $	*/
 /* $NetBSD: sched.h,v 1.2 1999/02/28 18:14:58 ross Exp $ */
 
 /*-
@@ -138,6 +138,7 @@ struct cpu_info;
 void roundrobin(struct cpu_info *);
 
 void sched_init_cpu(struct cpu_info *);
+void sched_idle(void *);
 void sched_exit(struct proc *);
 void mi_switch(void);
 void cpu_switchto(struct proc *, struct proc *);
@@ -149,6 +150,11 @@ void cpu_idle_cycle(void);
 void cpu_idle_leave(void);
 void sched_peg_curproc(struct cpu_info *ci);
 
+#ifdef MULTIPROCESSOR
+void sched_start_secondary_cpus(void);
+void sched_stop_secondary_cpus(void);
+#endif
+
 #define curcpu_is_idle()	(curcpu()->ci_schedstate.spc_whichqs == 0)
 
 void sched_init_runqueues(void);