6 files changed, 51 insertions, 9 deletions
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index a92bce40b04b..d05e1e9a553c 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -566,7 +566,7 @@ enum
  *
  * _ RCU:
  * 	1) rcutree_migrate_callbacks() migrates the queue.
- * 	2) rcu_report_dead() reports the final quiescent states.
+ * 	2) rcutree_report_cpu_dead() reports the final quiescent states.
  *
  * _ IRQ_POLL: irq_poll_cpu_dead() migrates the queue
  */
diff --git a/include/linux/rcu_notifier.h b/include/linux/rcu_notifier.h
new file mode 100644
index 000000000000..ebf371364581
--- /dev/null
+++ b/include/linux/rcu_notifier.h
@@ -0,0 +1,32 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Read-Copy Update notifiers, initially RCU CPU stall notifier.
+ * Separate from rcupdate.h to avoid #include loops.
+ *
+ * Copyright (C) 2023 Paul E. McKenney.
+ */
+
+#ifndef __LINUX_RCU_NOTIFIER_H
+#define __LINUX_RCU_NOTIFIER_H
+
+// Actions for RCU CPU stall notifier calls.
+#define RCU_STALL_NOTIFY_NORM	1
+#define RCU_STALL_NOTIFY_EXP	2
+
+#ifdef CONFIG_RCU_STALL_COMMON
+
+#include <linux/notifier.h>
+#include <linux/types.h>
+
+int rcu_stall_chain_notifier_register(struct notifier_block *n);
+int rcu_stall_chain_notifier_unregister(struct notifier_block *n);
+
+#else // #ifdef CONFIG_RCU_STALL_COMMON
+
+// No RCU CPU stall warnings in Tiny RCU.
+static inline int rcu_stall_chain_notifier_register(struct notifier_block *n) { return -EEXIST; }
+static inline int rcu_stall_chain_notifier_unregister(struct notifier_block *n) { return -ENOENT; }
+
+#endif // #else // #ifdef CONFIG_RCU_STALL_COMMON
+
+#endif /* __LINUX_RCU_NOTIFIER_H */
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 5e5f920ade90..f7206b2623c9 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -122,8 +122,6 @@ static inline void call_rcu_hurry(struct rcu_head *head, rcu_callback_t func)
 void rcu_init(void);
 extern int rcu_scheduler_active;
 void rcu_sched_clock_irq(int user);
-void rcu_report_dead(unsigned int cpu);
-void rcutree_migrate_callbacks(int cpu);
 
 #ifdef CONFIG_TASKS_RCU_GENERIC
 void rcu_init_tasks_generic(void);
diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h
index 7b949292908a..d9ac7b136aea 100644
--- a/include/linux/rcutiny.h
+++ b/include/linux/rcutiny.h
@@ -171,6 +171,6 @@ static inline void rcu_all_qs(void) { barrier(); }
 #define rcutree_offline_cpu      NULL
 #define rcutree_dead_cpu         NULL
 #define rcutree_dying_cpu        NULL
-static inline void rcu_cpu_starting(unsigned int cpu) { }
+static inline void rcutree_report_cpu_starting(unsigned int cpu) { }
 
 #endif /* __LINUX_RCUTINY_H */
diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h
index 126f6b418f6a..254244202ea9 100644
--- a/include/linux/rcutree.h
+++ b/include/linux/rcutree.h
@@ -37,7 +37,6 @@ void synchronize_rcu_expedited(void);
 void kvfree_call_rcu(struct rcu_head *head, void *ptr);
 
 void rcu_barrier(void);
-bool rcu_eqs_special_set(int cpu);
 void rcu_momentary_dyntick_idle(void);
 void kfree_rcu_scheduler_running(void);
 bool rcu_gp_might_be_stalled(void);
@@ -111,9 +110,21 @@ void rcu_all_qs(void);
 /* RCUtree hotplug events */
 int rcutree_prepare_cpu(unsigned int cpu);
 int rcutree_online_cpu(unsigned int cpu);
-int rcutree_offline_cpu(unsigned int cpu);
+void rcutree_report_cpu_starting(unsigned int cpu);
+
+#ifdef CONFIG_HOTPLUG_CPU
 int rcutree_dead_cpu(unsigned int cpu);
 int rcutree_dying_cpu(unsigned int cpu);
-void rcu_cpu_starting(unsigned int cpu);
+int rcutree_offline_cpu(unsigned int cpu);
+#else
+#define rcutree_dead_cpu NULL
+#define rcutree_dying_cpu NULL
+#define rcutree_offline_cpu NULL
+#endif
+
+void rcutree_migrate_callbacks(int cpu);
+
+/* Called from hotplug and also arm64 early secondary boot failure */
+void rcutree_report_cpu_dead(void);
 
 #endif /* __LINUX_RCUTREE_H */
diff --git a/include/linux/slab.h b/include/linux/slab.h
index 8228d1276a2f..ff56ab804bf6 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -245,8 +245,9 @@ DEFINE_FREE(kfree, void *, if (_T) kfree(_T))
 size_t ksize(const void *objp);
 
 #ifdef CONFIG_PRINTK
-bool kmem_valid_obj(void *object);
-void kmem_dump_obj(void *object);
+bool kmem_dump_obj(void *object);
+#else
+static inline bool kmem_dump_obj(void *object) { return false; }
 #endif
 
 /*