diff --git a/cddl/contrib/opensolaris/lib/libdtrace/common/dt_aggregate.c b/cddl/contrib/opensolaris/lib/libdtrace/common/dt_aggregate.c
--- a/cddl/contrib/opensolaris/lib/libdtrace/common/dt_aggregate.c
+++ b/cddl/contrib/opensolaris/lib/libdtrace/common/dt_aggregate.c
@@ -1092,8 +1092,10 @@
 	assert(agp->dtat_ncpu == 0);
 	assert(agp->dtat_cpus == NULL);
 
-	agp->dtat_maxcpu = dt_sysconf(dtp, _SC_CPUID_MAX) + 1;
-	agp->dtat_ncpu = dt_sysconf(dtp, _SC_NPROCESSORS_MAX);
+	agp->dtat_maxcpu = dt_cpu_maxid(dtp) + 1;
+	if (agp->dtat_maxcpu <= 0)
+		return (-1);
+	agp->dtat_ncpu = dt_sysconf(dtp, _SC_NPROCESSORS_CONF);
 	agp->dtat_cpus = malloc(agp->dtat_ncpu * sizeof (processorid_t));
 
 	if (agp->dtat_cpus == NULL)
diff --git a/cddl/contrib/opensolaris/lib/libdtrace/common/dt_consume.c b/cddl/contrib/opensolaris/lib/libdtrace/common/dt_consume.c
--- a/cddl/contrib/opensolaris/lib/libdtrace/common/dt_consume.c
+++ b/cddl/contrib/opensolaris/lib/libdtrace/common/dt_consume.c
@@ -3949,8 +3949,8 @@
 		return (rval);
 	}
 
-	if (max_ncpus == 0)
-		max_ncpus = dt_sysconf(dtp, _SC_CPUID_MAX) + 1;
+	if (max_ncpus == 0 && (max_ncpus = dt_cpu_maxid(dtp) + 1) <= 0)
+		return (-1);
 
 	for (i = 0; i < max_ncpus; i++) {
 		dtrace_bufdesc_t *nbuf;
@@ -4040,8 +4040,8 @@
 	if (!dtp->dt_active)
 		return (dt_set_errno(dtp, EINVAL));
 
-	if (max_ncpus == 0)
-		max_ncpus = dt_sysconf(dtp, _SC_CPUID_MAX) + 1;
+	if (max_ncpus == 0 && (max_ncpus = dt_cpu_maxid(dtp) + 1) <= 0)
+		return (-1);
 
 	if (pf == NULL)
 		pf = (dtrace_consume_probe_f *)dt_nullprobe;
diff --git a/cddl/contrib/opensolaris/lib/libdtrace/common/dt_impl.h b/cddl/contrib/opensolaris/lib/libdtrace/common/dt_impl.h
--- a/cddl/contrib/opensolaris/lib/libdtrace/common/dt_impl.h
+++ b/cddl/contrib/opensolaris/lib/libdtrace/common/dt_impl.h
@@ -620,6 +620,7 @@
  */
 extern char *dt_cpp_add_arg(dtrace_hdl_t *, const char *);
 extern char *dt_cpp_pop_arg(dtrace_hdl_t *);
+extern int dt_cpu_maxid(dtrace_hdl_t *);
 
 #ifdef illumos
 extern int dt_set_errno(dtrace_hdl_t *, int);
diff --git a/cddl/contrib/opensolaris/lib/libdtrace/common/dt_subr.c b/cddl/contrib/opensolaris/lib/libdtrace/common/dt_subr.c
--- a/cddl/contrib/opensolaris/lib/libdtrace/common/dt_subr.c
+++ b/cddl/contrib/opensolaris/lib/libdtrace/common/dt_subr.c
@@ -463,6 +463,20 @@
 	return (arg);
 }
 
+int
+dt_cpu_maxid(dtrace_hdl_t *dtp)
+{
+	size_t len;
+	u_int count;
+	int error;
+
+	len = sizeof(count);
+	error = sysctlbyname("kern.smp.maxid", &count, &len, NULL, 0);
+	if (error != 0)
+		return (dt_set_errno(dtp, errno));
+	return (count);
+}
+
 /*PRINTFLIKE1*/
 void
 dt_dprintf(const char *format, ...)
diff --git a/cddl/contrib/opensolaris/lib/libdtrace/common/dtrace.h b/cddl/contrib/opensolaris/lib/libdtrace/common/dtrace.h
--- a/cddl/contrib/opensolaris/lib/libdtrace/common/dtrace.h
+++ b/cddl/contrib/opensolaris/lib/libdtrace/common/dtrace.h
@@ -620,11 +620,6 @@
 }
 #endif
 
-#ifndef illumos
-#define _SC_CPUID_MAX		_SC_NPROCESSORS_CONF
-#define _SC_NPROCESSORS_MAX	_SC_NPROCESSORS_CONF
-#endif
-
 /*
  * Values for the dt_oformat property.
  */