diff --git a/Documentation/admin-guide/mm/memory-hotplug.rst b/Documentation/admin-guide/mm/memory-hotplug.rst
index a3c9e8ad8fa0..15fd1751a63c 100644
--- a/Documentation/admin-guide/mm/memory-hotplug.rst
+++ b/Documentation/admin-guide/mm/memory-hotplug.rst
@@ -293,6 +293,14 @@ The following files are currently defined:
 		       Availability depends on the CONFIG_ARCH_MEMORY_PROBE
 		       kernel configuration option.
 ``uevent``	       read-write: generic udev file for device subsystems.
+``crash_hotplug``      read-only: when changes to the system memory map
+		       occur due to hot un/plug of memory, this file contains
+		       '1' if the kernel updates the kdump capture kernel memory
+		       map itself (via elfcorehdr), or '0' if userspace must update
+		       the kdump capture kernel memory map.
+
+		       Availability depends on the CONFIG_MEMORY_HOTPLUG kernel
+		       configuration option.
 ====================== =========================================================
 
 .. note::
diff --git a/Documentation/core-api/cpu_hotplug.rst b/Documentation/core-api/cpu_hotplug.rst
index f75778d37488..0c8dc3fe5f94 100644
--- a/Documentation/core-api/cpu_hotplug.rst
+++ b/Documentation/core-api/cpu_hotplug.rst
@@ -750,6 +750,24 @@ will receive all events. A script like::
 
 can process the event further.
 
+When changes to the CPUs in the system occur, the sysfs file
+/sys/devices/system/cpu/crash_hotplug contains '1' if the kernel
+updates the kdump capture kernel list of CPUs itself (via elfcorehdr),
+or '0' if userspace must update the kdump capture kernel list of CPUs.
+
+The availability depends on the CONFIG_HOTPLUG_CPU kernel configuration
+option.
+
+To skip userspace processing of CPU hot un/plug events for kdump
+(ie the unload-then-reload to obtain a current list of CPUs), this sysfs
+file can be used in a udev rule as follows:
+
+ SUBSYSTEM=="cpu", ATTRS{crash_hotplug}=="1", GOTO="kdump_reload_end"
+
+For a cpu hot un/plug event, if the architecture supports kernel updates
+of the elfcorehdr (which contains the list of CPUs), then the rule skips
+the unload-then-reload of the kdump capture kernel.
+
 Kernel Inline Documentations Reference
 ======================================
 
diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
index 4c98849577d4..fedbf87f9d13 100644
--- a/drivers/base/cpu.c
+++ b/drivers/base/cpu.c
@@ -293,6 +293,17 @@ static ssize_t print_cpus_nohz_full(struct device *dev,
 static DEVICE_ATTR(nohz_full, 0444, print_cpus_nohz_full, NULL);
 #endif
 
+#ifdef CONFIG_HOTPLUG_CPU
+#include <linux/kexec.h>
+static ssize_t crash_hotplug_show(struct device *dev,
+				     struct device_attribute *attr,
+				     char *buf)
+{
+	return sprintf(buf, "%d\n", crash_hotplug_cpu_support());
+}
+static DEVICE_ATTR_ADMIN_RO(crash_hotplug);
+#endif
+
 static void cpu_device_release(struct device *dev)
 {
 	/*
@@ -469,6 +480,9 @@ static struct attribute *cpu_root_attrs[] = {
 #ifdef CONFIG_NO_HZ_FULL
 	&dev_attr_nohz_full.attr,
 #endif
+#ifdef CONFIG_HOTPLUG_CPU
+	&dev_attr_crash_hotplug.attr,
+#endif
 #ifdef CONFIG_GENERIC_CPU_AUTOPROBE
 	&dev_attr_modalias.attr,
 #endif
diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index fe98fb8d94e5..a3f37cb57d79 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -495,6 +495,16 @@ static ssize_t auto_online_blocks_store(struct device *dev,
 
 static DEVICE_ATTR_RW(auto_online_blocks);
 
+#ifdef CONFIG_MEMORY_HOTPLUG
+#include <linux/kexec.h>
+static ssize_t crash_hotplug_show(struct device *dev,
+				       struct device_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%d\n", crash_hotplug_memory_support());
+}
+static DEVICE_ATTR_RO(crash_hotplug);
+#endif
+
 /*
  * Some architectures will have custom drivers to do this, and
  * will not need to do it from userspace.  The fake hot-add code
@@ -894,6 +904,9 @@ static struct attribute *memory_root_attrs[] = {
 
 	&dev_attr_block_size_bytes.attr,
 	&dev_attr_auto_online_blocks.attr,
+#ifdef CONFIG_MEMORY_HOTPLUG
+	&dev_attr_crash_hotplug.attr,
+#endif
 	NULL
 };
 
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index a1838699d7b2..0b1ad1ac06e3 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -512,6 +512,14 @@ static inline void arch_kexec_pre_free_pages(void *vaddr, unsigned int pages) {
 static inline void arch_crash_handle_hotplug_event(struct kimage *image) { }
 #endif
 
+#ifndef crash_hotplug_cpu_support
+static inline int crash_hotplug_cpu_support(void) { return 0; }
+#endif
+
+#ifndef crash_hotplug_memory_support
+static inline int crash_hotplug_memory_support(void) { return 0; }
+#endif
+
 #else /* !CONFIG_KEXEC_CORE */
 struct pt_regs;
 struct task_struct;
