Add an MD callout like cpu_exit, but which is called after sched_lock is

obtained, when all other scheduling activity is suspended.  This is needed
on sparc64 to deactivate the vmspace of the exiting process on all cpus.
Otherwise if another unrelated process gets the exact same vmspace structure
allocated to it (same address), its address space will not be activated
properly.  This seems to fix some spontaneous signal 11 problems with smp
on sparc64.

sys/alpha/alpha/vm_machdep.c

@@ -247,6 +247,12 @@ cpu_exit(td)
 	alpha_fpstate_drop(td);
 }
 
+void
+cpu_sched_exit(td)
+	register struct thread *td;
+{
+}
+
 void
 cpu_wait(p)
 	struct proc *p;

sys/amd64/amd64/vm_machdep.c

@@ -282,6 +282,12 @@ cpu_exit(td)
         }
 }
 
+void
+cpu_sched_exit(td)
+	register struct thread *td;
+{
+}
+
 void
 cpu_wait(p)
 	struct proc *p;

sys/i386/i386/vm_machdep.c

@@ -282,6 +282,12 @@ cpu_exit(td)
         }
 }
 
+void
+cpu_sched_exit(td)
+	register struct thread *td;
+{
+}
+
 void
 cpu_wait(p)
 	struct proc *p;

sys/ia64/ia64/vm_machdep.c

@@ -313,6 +313,12 @@ cpu_exit(td)
 	ia64_fpstate_drop(td);
 }
 
+void
+cpu_sched_exit(td)
+	register struct thread *td;
+{
+}
+
 void
 cpu_wait(p)
 	struct proc *p;

sys/kern/kern_exit.c

@@ -448,6 +448,7 @@ exit1(td, rv)
 	binuptime(PCPU_PTR(switchtime));
 	PCPU_SET(switchticks, ticks);
 
+	cpu_sched_exit(td);
 	cpu_throw();
 	panic("exit1");
 }

sys/powerpc/aim/vm_machdep.c

@@ -208,6 +208,12 @@ cpu_exit(td)
 {
 }
 
+void
+cpu_sched_exit(td)
+	register struct thread *td;
+{
+}
+
 void
 cpu_wait(td)
 	struct proc *td;

sys/powerpc/powerpc/vm_machdep.c

@@ -208,6 +208,12 @@ cpu_exit(td)
 {
 }
 
+void
+cpu_sched_exit(td)
+	register struct thread *td;
+{
+}
+
 void
 cpu_wait(td)
 	struct proc *td;

sys/sparc64/sparc64/vm_machdep.c

@@ -86,6 +86,28 @@ cpu_exit(struct thread *td)
 	}
 }
 
+void
+cpu_sched_exit(struct thread *td)
+{
+	struct vmspace *vm;
+	struct pcpu *pc;
+	struct proc *p;
+
+	mtx_assert(&sched_lock, MA_OWNED);
+
+	p = td->td_proc;
+	vm = p->p_vmspace;
+	if (vm->vm_refcnt > 1)
+		return;
+	SLIST_FOREACH(pc, &cpuhead, pc_allcpu) {
+		if (pc->pc_vmspace == vm) {
+			vm->vm_pmap.pm_active &= ~pc->pc_cpumask;
+			vm->vm_pmap.pm_context[pc->pc_cpuid] = -1;
+			pc->pc_vmspace = NULL;
+		}
+	}
+}
+
 /*
  * Finish a fork operation, with process p2 nearly set up.
  * Copy and update the pcb, set up the stack so that the child

sys/sys/proc.h

@@ -752,6 +752,7 @@ void	userret(struct thread *, struct trapframe *, u_int);
 void	maybe_resched(struct thread *);
 
 void	cpu_exit(struct thread *);
+void	cpu_sched_exit(struct thread *);
 void	exit1(struct thread *, int) __dead2;
 void	cpu_fork(struct thread *, struct proc *, struct thread *, int);
 void	cpu_set_fork_handler(struct thread *, void (*)(void *), void *);