diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 4f81a14aa76aa58480b981fd7259bb57eb115230..0f9f77d3139e2d981148d61e1e5e7de59919fa23 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -4250,6 +4250,10 @@
 			value, meaning that RCU_SOFTIRQ is used by default.
 			Specify rcutree.use_softirq=0 to use rcuc kthreads.
 
+			But note that CONFIG_PREEMPT_RT=y kernels disable
+			this kernel boot parameter, forcibly setting it
+			to zero.
+
 	rcutree.rcu_fanout_exact= [KNL]
 			Disable autobalancing of the rcu_node combining
 			tree.  This is used by rcutorture, and might
@@ -4628,6 +4632,13 @@
 			only normal grace-period primitives.  No effect
 			on CONFIG_TINY_RCU kernels.
 
+			But note that CONFIG_PREEMPT_RT=y kernels enables
+			this kernel boot parameter, forcibly setting
+			it to the value one, that is, converting any
+			post-boot attempt at an expedited RCU grace
+			period to instead use normal non-expedited
+			grace-period processing.
+
 	rcupdate.rcu_task_ipi_delay= [KNL]
 			Set time in jiffies during which RCU tasks will
 			avoid sending IPIs, starting with the beginning
diff --git a/kernel/rcu/Kconfig b/kernel/rcu/Kconfig
index cd6e11403f1b11730eedfd5c04f43b1ffa50270b..0c71197857f683ad7eb5f38a2c9d31f4a5fce51e 100644
--- a/kernel/rcu/Kconfig
+++ b/kernel/rcu/Kconfig
@@ -189,8 +189,8 @@ config RCU_FAST_NO_HZ
 
 config RCU_BOOST
 	bool "Enable RCU priority boosting"
-	depends on RT_MUTEXES && PREEMPT_RCU && RCU_EXPERT
-	default n
+	depends on (RT_MUTEXES && PREEMPT_RCU && RCU_EXPERT) || PREEMPT_RT
+	default y if PREEMPT_RT
 	help
 	  This option boosts the priority of preempted RCU readers that
 	  block the current preemptible RCU grace period for too long.
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index b41009a283cafca0f89508cf84695d8ae1ff1f90..3d6755cab5e1d8b464e3a7edf288ea2e2648a495 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -100,8 +100,10 @@ static struct rcu_state rcu_state = {
 static bool dump_tree;
 module_param(dump_tree, bool, 0444);
 /* By default, use RCU_SOFTIRQ instead of rcuc kthreads. */
-static bool use_softirq = true;
+static bool use_softirq = !IS_ENABLED(CONFIG_PREEMPT_RT);
+#ifndef CONFIG_PREEMPT_RT
 module_param(use_softirq, bool, 0444);
+#endif
 /* Control rcu_node-tree auto-balancing at boot time. */
 static bool rcu_fanout_exact;
 module_param(rcu_fanout_exact, bool, 0444);
diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c
index 849f0aa99333bd8a4f0da858854c5e8afc2d93d1..dd94a602a6d253e4ea27e8866c329aefa3bbcaed 100644
--- a/kernel/rcu/update.c
+++ b/kernel/rcu/update.c
@@ -56,8 +56,10 @@
 #ifndef CONFIG_TINY_RCU
 module_param(rcu_expedited, int, 0);
 module_param(rcu_normal, int, 0);
-static int rcu_normal_after_boot;
+static int rcu_normal_after_boot = IS_ENABLED(CONFIG_PREEMPT_RT);
+#ifndef CONFIG_PREEMPT_RT
 module_param(rcu_normal_after_boot, int, 0);
+#endif
 #endif /* #ifndef CONFIG_TINY_RCU */
 
 #ifdef CONFIG_DEBUG_LOCK_ALLOC