Merge branch 'topic/kdump-hotplug' into nextnext

Merge our topic branch containing kdump hotplug changes, more detail from the
original cover letter:

Commit 247262756121 ("crash: add generic infrastructure for crash
hotplug support") added a generic infrastructure that allows
architectures to selectively update the kdump image component during CPU
or memory add/remove events within the kernel itself.

This patch series adds crash hotplug handler for PowerPC and enable
support to update the kdump image on CPU/Memory add/remove events.

Among the 6 patches in this series, the first two patches make changes
to the generic crash hotplug handler to assist PowerPC in adding support
for this feature. The last four patches add support for this feature.

The following section outlines the problem addressed by this patch
series, along with the current solution, its shortcomings, and the
proposed resolution.

Problem:
========
Due to CPU/Memory hotplug or online/offline events the elfcorehdr
(which describes the CPUs and memory of the crashed kernel) and FDT
(Flattened Device Tree) of kdump image becomes outdated. Consequently,
attempting dump collection with an outdated elfcorehdr or FDT can lead
to failed or inaccurate dump collection.

Going forward CPU hotplug or online/offline events are referred as
CPU/Memory add/remove events.

Existing solution and its shortcoming:
======================================
The current solution to address the above issue involves monitoring the
CPU/memory add/remove events in userspace using udev rules and whenever
there are changes in CPU and memory resources, the entire kdump image
is loaded again. The kdump image includes kernel, initrd, elfcorehdr,
FDT, purgatory. Given that only elfcorehdr and FDT get outdated due to
CPU/Memory add/remove events, reloading the entire kdump image is
inefficient. More importantly, kdump remains inactive for a substantial
amount of time until the kdump reload completes.

Proposed solution:
==================
Instead of initiating a full kdump image reload from userspace on
CPU/Memory hotplug and online/offline events, the proposed solution aims
to update only the necessary kdump image component within the kernel
itself.

19 files changed, 713 insertions, 359 deletions

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 1c4be337368604..a1a3b336300806 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -686,6 +686,10 @@ config ARCH_SELECTS_CRASH_DUMP
 	depends on CRASH_DUMP
 	select RELOCATABLE if PPC64 || 44x || PPC_85xx
 
+config ARCH_SUPPORTS_CRASH_HOTPLUG
+	def_bool y
+	depends on PPC64
+
 config FA_DUMP
 	bool "Firmware-assisted dump"
 	depends on CRASH_DUMP && PPC64 && (PPC_RTAS || PPC_POWERNV)
diff --git a/arch/powerpc/include/asm/kexec.h b/arch/powerpc/include/asm/kexec.h
index fdb90e24dc74d4..95a98b390d62df 100644
--- a/arch/powerpc/include/asm/kexec.h
+++ b/arch/powerpc/include/asm/kexec.h
@@ -135,6 +135,17 @@ static inline void crash_setup_regs(struct pt_regs *newregs,
 		ppc_save_regs(newregs);
 }
 
+#ifdef CONFIG_CRASH_HOTPLUG
+void arch_crash_handle_hotplug_event(struct kimage *image, void *arg);
+#define arch_crash_handle_hotplug_event arch_crash_handle_hotplug_event
+
+int arch_crash_hotplug_support(struct kimage *image, unsigned long kexec_flags);
+#define arch_crash_hotplug_support arch_crash_hotplug_support
+
+unsigned int arch_crash_get_elfcorehdr_size(void);
+#define crash_get_elfcorehdr_size arch_crash_get_elfcorehdr_size
+#endif /* CONFIG_CRASH_HOTPLUG */
+
 extern int crashing_cpu;
 extern void crash_send_ipi(void (*crash_ipi_callback)(struct pt_regs *));
 extern void crash_ipi_callback(struct pt_regs *regs);
@@ -185,6 +196,10 @@ static inline void crash_send_ipi(void (*crash_ipi_callback)(struct pt_regs *))
 
 #endif /* CONFIG_CRASH_DUMP */
 
+#if defined(CONFIG_KEXEC_FILE) || defined(CONFIG_CRASH_DUMP)
+int update_cpus_node(void *fdt);
+#endif
+
 #ifdef CONFIG_PPC_BOOK3S_64
 #include <asm/book3s/64/kexec.h>
 #endif
diff --git a/arch/powerpc/include/asm/kexec_ranges.h b/arch/powerpc/include/asm/kexec_ranges.h
index f83866a19e870f..14055896cbcbcd 100644
--- a/arch/powerpc/include/asm/kexec_ranges.h
+++ b/arch/powerpc/include/asm/kexec_ranges.h
@@ -7,19 +7,9 @@
 void sort_memory_ranges(struct crash_mem *mrngs, bool merge);
 struct crash_mem *realloc_mem_ranges(struct crash_mem **mem_ranges);
 int add_mem_range(struct crash_mem **mem_ranges, u64 base, u64 size);
-int add_tce_mem_ranges(struct crash_mem **mem_ranges);
-int add_initrd_mem_range(struct crash_mem **mem_ranges);
-#ifdef CONFIG_PPC_64S_HASH_MMU
-int add_htab_mem_range(struct crash_mem **mem_ranges);
-#else
-static inline int add_htab_mem_range(struct crash_mem **mem_ranges)
-{
-	return 0;
-}
-#endif
-int add_kernel_mem_range(struct crash_mem **mem_ranges);
-int add_rtas_mem_range(struct crash_mem **mem_ranges);
-int add_opal_mem_range(struct crash_mem **mem_ranges);
-int add_reserved_mem_ranges(struct crash_mem **mem_ranges);
-
+int remove_mem_range(struct crash_mem **mem_ranges, u64 base, u64 size);
+int get_exclude_memory_ranges(struct crash_mem **mem_ranges);
+int get_reserved_memory_ranges(struct crash_mem **mem_ranges);
+int get_crash_memory_ranges(struct crash_mem **mem_ranges);
+int get_usable_memory_ranges(struct crash_mem **mem_ranges);
 #endif /* _ASM_POWERPC_KEXEC_RANGES_H */
diff --git a/arch/powerpc/kexec/Makefile b/arch/powerpc/kexec/Makefile
index 8e469c4da3f882..470eb0453e17f3 100644
--- a/arch/powerpc/kexec/Makefile
+++ b/arch/powerpc/kexec/Makefile
@@ -3,11 +3,11 @@
 # Makefile for the linux kernel.
 #
 
-obj-y				+= core.o core_$(BITS).o
+obj-y				+= core.o core_$(BITS).o ranges.o
 
 obj-$(CONFIG_PPC32)		+= relocate_32.o
 
-obj-$(CONFIG_KEXEC_FILE)	+= file_load.o ranges.o file_load_$(BITS).o elf_$(BITS).o
+obj-$(CONFIG_KEXEC_FILE)	+= file_load.o file_load_$(BITS).o elf_$(BITS).o
 obj-$(CONFIG_VMCORE_INFO)	+= vmcore_info.o
 obj-$(CONFIG_CRASH_DUMP)	+= crash.o
 
diff --git a/arch/powerpc/kexec/core_64.c b/arch/powerpc/kexec/core_64.c
index 762e4d09aacfab..85050be08a23da 100644
--- a/arch/powerpc/kexec/core_64.c
+++ b/arch/powerpc/kexec/core_64.c
@@ -17,6 +17,7 @@
 #include <linux/cpu.h>
 #include <linux/hardirq.h>
 #include <linux/of.h>
+#include <linux/libfdt.h>
 
 #include <asm/page.h>
 #include <asm/current.h>
@@ -30,6 +31,7 @@
 #include <asm/hw_breakpoint.h>
 #include <asm/svm.h>
 #include <asm/ultravisor.h>
+#include <asm/crashdump-ppc64.h>
 
 int machine_kexec_prepare(struct kimage *image)
 {
@@ -419,3 +421,92 @@ static int __init export_htab_values(void)
 }
 late_initcall(export_htab_values);
 #endif /* CONFIG_PPC_64S_HASH_MMU */
+
+#if defined(CONFIG_KEXEC_FILE) || defined(CONFIG_CRASH_DUMP)
+/**
+ * add_node_props - Reads node properties from device node structure and add
+ *                  them to fdt.
+ * @fdt:            Flattened device tree of the kernel
+ * @node_offset:    offset of the node to add a property at
+ * @dn:             device node pointer
+ *
+ * Returns 0 on success, negative errno on error.
+ */
+static int add_node_props(void *fdt, int node_offset, const struct device_node *dn)
+{
+	int ret = 0;
+	struct property *pp;
+
+	if (!dn)
+		return -EINVAL;
+
+	for_each_property_of_node(dn, pp) {
+		ret = fdt_setprop(fdt, node_offset, pp->name, pp->value, pp->length);
+		if (ret < 0) {
+			pr_err("Unable to add %s property: %s\n", pp->name, fdt_strerror(ret));
+			return ret;
+		}
+	}
+	return ret;
+}
+
+/**
+ * update_cpus_node - Update cpus node of flattened device tree using of_root
+ *                    device node.
+ * @fdt:              Flattened device tree of the kernel.
+ *
+ * Returns 0 on success, negative errno on error.
+ */
+int update_cpus_node(void *fdt)
+{
+	struct device_node *cpus_node, *dn;
+	int cpus_offset, cpus_subnode_offset, ret = 0;
+
+	cpus_offset = fdt_path_offset(fdt, "/cpus");
+	if (cpus_offset < 0 && cpus_offset != -FDT_ERR_NOTFOUND) {
+		pr_err("Malformed device tree: error reading /cpus node: %s\n",
+		       fdt_strerror(cpus_offset));
+		return cpus_offset;
+	}
+
+	if (cpus_offset > 0) {
+		ret = fdt_del_node(fdt, cpus_offset);
+		if (ret < 0) {
+			pr_err("Error deleting /cpus node: %s\n", fdt_strerror(ret));
+			return -EINVAL;
+		}
+	}
+
+	/* Add cpus node to fdt */
+	cpus_offset = fdt_add_subnode(fdt, fdt_path_offset(fdt, "/"), "cpus");
+	if (cpus_offset < 0) {
+		pr_err("Error creating /cpus node: %s\n", fdt_strerror(cpus_offset));
+		return -EINVAL;
+	}
+
+	/* Add cpus node properties */
+	cpus_node = of_find_node_by_path("/cpus");
+	ret = add_node_props(fdt, cpus_offset, cpus_node);
+	of_node_put(cpus_node);
+	if (ret < 0)
+		return ret;
+
+	/* Loop through all subnodes of cpus and add them to fdt */
+	for_each_node_by_type(dn, "cpu") {
+		cpus_subnode_offset = fdt_add_subnode(fdt, cpus_offset, dn->full_name);
+		if (cpus_subnode_offset < 0) {
+			pr_err("Unable to add %s subnode: %s\n", dn->full_name,
+			       fdt_strerror(cpus_subnode_offset));
+			ret = cpus_subnode_offset;
+			goto out;
+		}
+
+		ret = add_node_props(fdt, cpus_subnode_offset, dn);
+		if (ret < 0)
+			goto out;
+	}
+out:
+	of_node_put(dn);
+	return ret;
+}
+#endif /* CONFIG_KEXEC_FILE || CONFIG_CRASH_DUMP */
diff --git a/arch/powerpc/kexec/crash.c b/arch/powerpc/kexec/crash.c
index ef5c2d25ec3976..9ac3266e496522 100644
--- a/arch/powerpc/kexec/crash.c
+++ b/arch/powerpc/kexec/crash.c
@@ -16,6 +16,8 @@
 #include <linux/delay.h>
 #include <linux/irq.h>
 #include <linux/types.h>
+#include <linux/libfdt.h>
+#include <linux/memory.h>
 
 #include <asm/processor.h>
 #include <asm/machdep.h>
@@ -24,6 +26,7 @@
 #include <asm/setjmp.h>
 #include <asm/debug.h>
 #include <asm/interrupt.h>
+#include <asm/kexec_ranges.h>
 
 /*
  * The primary CPU waits a while for all secondary CPUs to enter. This is to
@@ -392,3 +395,195 @@ void default_machine_crash_shutdown(struct pt_regs *regs)
 	if (ppc_md.kexec_cpu_down)
 		ppc_md.kexec_cpu_down(1, 0);
 }
+
+#ifdef CONFIG_CRASH_HOTPLUG
+#undef pr_fmt
+#define pr_fmt(fmt) "crash hp: " fmt
+
+/*
+ * Advertise preferred elfcorehdr size to userspace via
+ * /sys/kernel/crash_elfcorehdr_size sysfs interface.
+ */
+unsigned int arch_crash_get_elfcorehdr_size(void)
+{
+	unsigned long phdr_cnt;
+
+	/* A program header for possible CPUs + vmcoreinfo */
+	phdr_cnt = num_possible_cpus() + 1;
+	if (IS_ENABLED(CONFIG_MEMORY_HOTPLUG))
+		phdr_cnt += CONFIG_CRASH_MAX_MEMORY_RANGES;
+
+	return sizeof(struct elfhdr) + (phdr_cnt * sizeof(Elf64_Phdr));
+}
+
+/**
+ * update_crash_elfcorehdr() - Recreate the elfcorehdr and replace it with old
+ *			       elfcorehdr in the kexec segment array.
+ * @image: the active struct kimage
+ * @mn: struct memory_notify data handler
+ */
+static void update_crash_elfcorehdr(struct kimage *image, struct memory_notify *mn)
+{
+	int ret;
+	struct crash_mem *cmem = NULL;
+	struct kexec_segment *ksegment;
+	void *ptr, *mem, *elfbuf = NULL;
+	unsigned long elfsz, memsz, base_addr, size;
+
+	ksegment = &image->segment[image->elfcorehdr_index];
+	mem = (void *) ksegment->mem;
+	memsz = ksegment->memsz;
+
+	ret = get_crash_memory_ranges(&cmem);
+	if (ret) {
+		pr_err("Failed to get crash mem range\n");
+		return;
+	}
+
+	/*
+	 * The hot unplugged memory is part of crash memory ranges,
+	 * remove it here.
+	 */
+	if (image->hp_action == KEXEC_CRASH_HP_REMOVE_MEMORY) {
+		base_addr = PFN_PHYS(mn->start_pfn);
+		size = mn->nr_pages * PAGE_SIZE;
+		ret = remove_mem_range(&cmem, base_addr, size);
+		if (ret) {
+			pr_err("Failed to remove hot-unplugged memory from crash memory ranges\n");
+			goto out;
+		}
+	}
+
+	ret = crash_prepare_elf64_headers(cmem, false, &elfbuf, &elfsz);
+	if (ret) {
+		pr_err("Failed to prepare elf header\n");
+		goto out;
+	}
+
+	/*
+	 * It is unlikely that kernel hit this because elfcorehdr kexec
+	 * segment (memsz) is built with addition space to accommodate growing
+	 * number of crash memory ranges while loading the kdump kernel. It is
+	 * Just to avoid any unforeseen case.
+	 */
+	if (elfsz > memsz) {
+		pr_err("Updated crash elfcorehdr elfsz %lu > memsz %lu", elfsz, memsz);
+		goto out;
+	}
+
+	ptr = __va(mem);
+	if (ptr) {
+		/* Temporarily invalidate the crash image while it is replaced */
+		xchg(&kexec_crash_image, NULL);
+
+		/* Replace the old elfcorehdr with newly prepared elfcorehdr */
+		memcpy((void *)ptr, elfbuf, elfsz);
+
+		/* The crash image is now valid once again */
+		xchg(&kexec_crash_image, image);
+	}
+out:
+	kvfree(cmem);
+	kvfree(elfbuf);
+}
+
+/**
+ * get_fdt_index - Loop through the kexec segment array and find
+ *		   the index of the FDT segment.
+ * @image: a pointer to kexec_crash_image
+ *
+ * Returns the index of FDT segment in the kexec segment array
+ * if found; otherwise -1.
+ */
+static int get_fdt_index(struct kimage *image)
+{
+	void *ptr;
+	unsigned long mem;
+	int i, fdt_index = -1;
+
+	/* Find the FDT segment index in kexec segment array. */
+	for (i = 0; i < image->nr_segments; i++) {
+		mem = image->segment[i].mem;
+		ptr = __va(mem);
+
+		if (ptr && fdt_magic(ptr) == FDT_MAGIC) {
+			fdt_index = i;
+			break;
+		}
+	}
+
+	return fdt_index;
+}
+
+/**
+ * update_crash_fdt - updates the cpus node of the crash FDT.
+ *
+ * @image: a pointer to kexec_crash_image
+ */
+static void update_crash_fdt(struct kimage *image)
+{
+	void *fdt;
+	int fdt_index;
+
+	fdt_index = get_fdt_index(image);
+	if (fdt_index < 0) {
+		pr_err("Unable to locate FDT segment.\n");
+		return;
+	}
+
+	fdt = __va((void *)image->segment[fdt_index].mem);
+
+	/* Temporarily invalidate the crash image while it is replaced */
+	xchg(&kexec_crash_image, NULL);
+
+	/* update FDT to reflect changes in CPU resources */
+	if (update_cpus_node(fdt))
+		pr_err("Failed to update crash FDT");
+
+	/* The crash image is now valid once again */
+	xchg(&kexec_crash_image, image);
+}
+
+int arch_crash_hotplug_support(struct kimage *image, unsigned long kexec_flags)
+{
+#ifdef CONFIG_KEXEC_FILE
+	if (image->file_mode)
+		return 1;
+#endif
+	return kexec_flags & KEXEC_CRASH_HOTPLUG_SUPPORT;
+}
+
+/**
+ * arch_crash_handle_hotplug_event - Handle crash CPU/Memory hotplug events to update the
+ *				     necessary kexec segments based on the hotplug event.
+ * @image: a pointer to kexec_crash_image
+ * @arg: struct memory_notify handler for memory hotplug case and NULL for CPU hotplug case.
+ *
+ * Update the kdump image based on the type of hotplug event, represented by image->hp_action.
+ * CPU add: Update the FDT segment to include the newly added CPU.
+ * CPU remove: No action is needed, with the assumption that it's okay to have offline CPUs
+ *	       part of the FDT.
+ * Memory add/remove: No action is taken as this is not yet supported.
+ */
+void arch_crash_handle_hotplug_event(struct kimage *image, void *arg)
+{
+	struct memory_notify *mn;
+
+	switch (image->hp_action) {
+	case KEXEC_CRASH_HP_REMOVE_CPU:
+		return;
+
+	case KEXEC_CRASH_HP_ADD_CPU:
+		update_crash_fdt(image);
+		break;
+
+	case KEXEC_CRASH_HP_REMOVE_MEMORY:
+	case KEXEC_CRASH_HP_ADD_MEMORY:
+		mn = (struct memory_notify *)arg;
+		update_crash_elfcorehdr(image, mn);
+		return;
+	default:
+		pr_warn_once("Unknown hotplug action\n");
+	}
+}
+#endif /* CONFIG_CRASH_HOTPLUG */
diff --git a/arch/powerpc/kexec/elf_64.c b/arch/powerpc/kexec/elf_64.c
index 6d8951e8e96663..214c071c58edf9 100644
--- a/arch/powerpc/kexec/elf_64.c
+++ b/arch/powerpc/kexec/elf_64.c
@@ -116,7 +116,8 @@ static void *elf64_load(struct kimage *image, char *kernel_buf,
 	if (ret)
 		goto out_free_fdt;
 
-	fdt_pack(fdt);
+	if (!IS_ENABLED(CONFIG_CRASH_HOTPLUG) || image->type != KEXEC_TYPE_CRASH)
+		fdt_pack(fdt);
 
 	kbuf.buffer = fdt;
 	kbuf.bufsz = kbuf.memsz = fdt_totalsize(fdt);
diff --git a/arch/powerpc/kexec/file_load_64.c b/arch/powerpc/kexec/file_load_64.c
index 1bc65de6174f3e..925a69ad24689d 100644
--- a/arch/powerpc/kexec/file_load_64.c
+++ b/arch/powerpc/kexec/file_load_64.c
@@ -30,6 +30,7 @@
 #include <asm/iommu.h>
 #include <asm/prom.h>
 #include <asm/plpks.h>
+#include <asm/cputhreads.h>
 
 struct umem_info {
 	__be64 *buf;		/* data buffer for usable-memory property */
@@ -48,83 +49,6 @@ const struct kexec_file_ops * const kexec_file_loaders[] = {
 };
 
 /**
- * get_exclude_memory_ranges - Get exclude memory ranges. This list includes
- *                             regions like opal/rtas, tce-table, initrd,
- *                             kernel, htab which should be avoided while
- *                             setting up kexec load segments.
- * @mem_ranges:                Range list to add the memory ranges to.
- *
- * Returns 0 on success, negative errno on error.
- */
-static int get_exclude_memory_ranges(struct crash_mem **mem_ranges)
-{
-	int ret;
-
-	ret = add_tce_mem_ranges(mem_ranges);
-	if (ret)
-		goto out;
-
-	ret = add_initrd_mem_range(mem_ranges);
-	if (ret)
-		goto out;
-
-	ret = add_htab_mem_range(mem_ranges);
-	if (ret)
-		goto out;
-
-	ret = add_kernel_mem_range(mem_ranges);
-	if (ret)
-		goto out;
-
-	ret = add_rtas_mem_range(mem_ranges);
-	if (ret)
-		goto out;
-
-	ret = add_opal_mem_range(mem_ranges);
-	if (ret)
-		goto out;
-
-	ret = add_reserved_mem_ranges(mem_ranges);
-	if (ret)
-		goto out;
-
-	/* exclude memory ranges should be sorted for easy lookup */
-	sort_memory_ranges(*mem_ranges, true);
-out:
-	if (ret)
-		pr_err("Failed to setup exclude memory ranges\n");
-	return ret;
-}
-
-/**
- * get_reserved_memory_ranges - Get reserve memory ranges. This list includes
- *                              memory regions that should be added to the
- *                              memory reserve map to ensure the region is
- *                              protected from any mischief.
- * @mem_ranges:                 Range list to add the memory ranges to.
- *
- * Returns 0 on success, negative errno on error.
- */
-static int get_reserved_memory_ranges(struct crash_mem **mem_ranges)
-{
-	int ret;
-
-	ret = add_rtas_mem_range(mem_ranges);
-	if (ret)
-		goto out;
-
-	ret = add_tce_mem_ranges(mem_ranges);
-	if (ret)
-		goto out;
-
-	ret = add_reserved_mem_ranges(mem_ranges);
-out:
-	if (ret)
-		pr_err("Failed to setup reserved memory ranges\n");
-	return ret;
-}
-
-/**
  * __locate_mem_hole_top_down - Looks top down for a large enough memory hole
  *                              in the memory regions between buf_min & buf_max
  *                              for the buffer. If found, sets kbuf->mem.
@@ -323,119 +247,6 @@ static int locate_mem_hole_bottom_up_ppc64(struct kexec_buf *kbuf,
 
 #ifdef CONFIG_CRASH_DUMP
 /**
- * get_usable_memory_ranges - Get usable memory ranges. This list includes
- *                            regions like crashkernel, opal/rtas & tce-table,
- *                            that kdump kernel could use.
- * @mem_ranges:               Range list to add the memory ranges to.
- *
- * Returns 0 on success, negative errno on error.
- */
-static int get_usable_memory_ranges(struct crash_mem **mem_ranges)
-{
-	int ret;
-
-	/*
-	 * Early boot failure observed on guests when low memory (first memory
-	 * block?) is not added to usable memory. So, add [0, crashk_res.end]
-	 * instead of [crashk_res.start, crashk_res.end] to workaround it.
-	 * Also, crashed kernel's memory must be added to reserve map to
-	 * avoid kdump kernel from using it.
-	 */
-	ret = add_mem_range(mem_ranges, 0, crashk_res.end + 1);
-	if (ret)
-		goto out;
-
-	ret = add_rtas_mem_range(mem_ranges);
-	if (ret)
-		goto out;
-
-	ret = add_opal_mem_range(mem_ranges);
-	if (ret)
-		goto out;
-
-	ret = add_tce_mem_ranges(mem_ranges);
-out:
-	if (ret)
-		pr_err("Failed to setup usable memory ranges\n");
-	return ret;
-}
-
-/**
- * get_crash_memory_ranges - Get crash memory ranges. This list includes
- *                           first/crashing kernel's memory regions that
- *                           would be exported via an elfcore.
- * @mem_ranges:              Range list to add the memory ranges to.
- *
- * Returns 0 on success, negative errno on error.
- */
-static int get_crash_memory_ranges(struct crash_mem **mem_ranges)
-{
-	phys_addr_t base, end;
-	struct crash_mem *tmem;
-	u64 i;
-	int ret;
-
-	for_each_mem_range(i, &base, &end) {
-		u64 size = end - base;
-
-		/* Skip backup memory region, which needs a separate entry */
-		if (base == BACKUP_SRC_START) {
-			if (size > BACKUP_SRC_SIZE) {
-				base = BACKUP_SRC_END + 1;
-				size -= BACKUP_SRC_SIZE;
-			} else
-				continue;
-		}
-
-		ret = add_mem_range(mem_ranges, base, size);
-		if (ret)
-			goto out;
-
-		/* Try merging adjacent ranges before reallocation attempt */
-		if ((*mem_ranges)->nr_ranges == (*mem_ranges)->max_nr_ranges)
-			sort_memory_ranges(*mem_ranges, true);
-	}
-
-	/* Reallocate memory ranges if there is no space to split ranges */
-	tmem = *mem_ranges;
-	if (tmem && (tmem->nr_ranges == tmem->max_nr_ranges)) {
-		tmem = realloc_mem_ranges(mem_ranges);
-		if (!tmem)
-			goto out;
-	}
-
-	/* Exclude crashkernel region */
-	ret = crash_exclude_mem_range(tmem, crashk_res.start, crashk_res.end);
-	if (ret)
-		goto out;
-
-	/*
-	 * FIXME: For now, stay in parity with kexec-tools but if RTAS/OPAL
-	 *        regions are exported to save their context at the time of
-	 *        crash, they should actually be backed up just like the
-	 *        first 64K bytes of memory.
-	 */
-	ret = add_rtas_mem_range(mem_ranges);
-	if (ret)
-		goto out;
-
-	ret = add_opal_mem_range(mem_ranges);
-	if (ret)
-		goto out;
-
-	/* create a separate program header for the backup region */
-	ret = add_mem_range(mem_ranges, BACKUP_SRC_START, BACKUP_SRC_SIZE);
-	if (ret)
-		goto out;
-
-	sort_memory_ranges(*mem_ranges, false);
-out:
-	if (ret)
-		pr_err("Failed to setup crash memory ranges\n");
-	return ret;
-}
-
-/**
  * check_realloc_usable_mem - Reallocate buffer if it can't accommodate entries
  * @um_info:                  Usable memory buffer and ranges info.
  * @cnt:                      No. of entries to accommodate.
@@ -784,6 +595,23 @@ static void update_backup_region_phdr(struct kimage *image, Elf64_Ehdr *ehdr)
 	}
 }
 
+static unsigned int kdump_extra_elfcorehdr_size(struct crash_mem *cmem)
+{
+#if defined(CONFIG_CRASH_HOTPLUG) && defined(CONFIG_MEMORY_HOTPLUG)
+	unsigned int extra_sz = 0;
+
+	if (CONFIG_CRASH_MAX_MEMORY_RANGES > (unsigned int)PN_XNUM)
+		pr_warn("Number of Phdrs %u exceeds max\n", CONFIG_CRASH_MAX_MEMORY_RANGES);
+	else if (cmem->nr_ranges >= CONFIG_CRASH_MAX_MEMORY_RANGES)
+		pr_warn("Configured crash mem ranges may not be enough\n");
+	else
+		extra_sz = (CONFIG_CRASH_MAX_MEMORY_RANGES - cmem->nr_ranges) * sizeof(Elf64_Phdr);
+
+	return extra_sz;
+#endif
+	return 0;
+}
+
 /**
  * load_elfcorehdr_segment - Setup crash memory ranges and initialize elfcorehdr
  *                           segment needed to load kdump kernel.
@@ -815,7 +643,8 @@ static int load_elfcorehdr_segment(struct kimage *image, struct kexec_buf *kbuf)
 
 	kbuf->buffer = headers;
 	kbuf->mem = KEXEC_BUF_MEM_UNKNOWN;
-	kbuf->bufsz = kbuf->memsz = headers_sz;
+	kbuf->bufsz = headers_sz;
+	kbuf->memsz = headers_sz + kdump_extra_elfcorehdr_size(cmem);
 	kbuf->top_down = false;
 
 	ret = kexec_add_buffer(kbuf);
@@ -979,6 +808,9 @@ static unsigned int kdump_extra_fdt_size_ppc64(struct kimage *image)
 	unsigned int cpu_nodes, extra_size = 0;
 	struct device_node *dn;
 	u64 usm_entries;
+#ifdef CONFIG_CRASH_HOTPLUG
+	unsigned int possible_cpu_nodes;
+#endif
 
 	if (!IS_ENABLED(CONFIG_CRASH_DUMP) || image->type != KEXEC_TYPE_CRASH)
 		return 0;
@@ -1006,6 +838,19 @@ static unsigned int kdump_extra_fdt_size_ppc64(struct kimage *image)
 	if (cpu_nodes > boot_cpu_node_count)
 		extra_size += (cpu_nodes - boot_cpu_node_count) * cpu_node_size();
 
+#ifdef CONFIG_CRASH_HOTPLUG
+	/*
+	 * Make sure enough space is reserved to accommodate possible CPU nodes
+	 * in the crash FDT. This allows packing possible CPU nodes which are
+	 * not yet present in the system without regenerating the entire FDT.
+	 */
+	if (image->type == KEXEC_TYPE_CRASH) {
+		possible_cpu_nodes = num_possible_cpus() / threads_per_core;
+		if (possible_cpu_nodes > cpu_nodes)
+			extra_size += (possible_cpu_nodes - cpu_nodes) * cpu_node_size();
+	}
+#endif
+
 	return extra_size;
 }
 
@@ -1028,93 +873,6 @@ unsigned int kexec_extra_fdt_size_ppc64(struct kimage *image)
 	return extra_size + kdump_extra_fdt_size_ppc64(image);
 }
 
-/**
- * add_node_props - Reads node properties from device node structure and add
- *                  them to fdt.
- * @fdt:            Flattened device tree of the kernel
- * @node_offset:    offset of the node to add a property at
- * @dn:             device node pointer
- *
- * Returns 0 on success, negative errno on error.
- */
-static int add_node_props(void *fdt, int node_offset, const struct device_node *dn)
-{
-	int ret = 0;
-	struct property *pp;
-
-	if (!dn)
-		return -EINVAL;
-
-	for_each_property_of_node(dn, pp) {
-		ret = fdt_setprop(fdt, node_offset, pp->name, pp->value, pp->length);
-		if (ret < 0) {
-			pr_err("Unable to add %s property: %s\n", pp->name, fdt_strerror(ret));
-			return ret;
-		}
-	}
-	return ret;
-}
-
-/**
- * update_cpus_node - Update cpus node of flattened device tree using of_root
- *                    device node.
- * @fdt:              Flattened device tree of the kernel.
- *
- * Returns 0 on success, negative errno on error.
- */
-static int update_cpus_node(void *fdt)
-{
-	struct device_node *cpus_node, *dn;
-	int cpus_offset, cpus_subnode_offset, ret = 0;
-
-	cpus_offset = fdt_path_offset(fdt, "/cpus");
-	if (cpus_offset < 0 && cpus_offset != -FDT_ERR_NOTFOUND) {
-		pr_err("Malformed device tree: error reading /cpus node: %s\n",
-		       fdt_strerror(cpus_offset));
-		return cpus_offset;
-	}
-
-	if (cpus_offset > 0) {
-		ret = fdt_del_node(fdt, cpus_offset);
-		if (ret < 0) {
-			pr_err("Error deleting /cpus node: %s\n", fdt_strerror(ret));
-			return -EINVAL;
-		}
-	}
-
-	/* Add cpus node to fdt */
-	cpus_offset = fdt_add_subnode(fdt, fdt_path_offset(fdt, "/"), "cpus");
-	if (cpus_offset < 0) {
-		pr_err("Error creating /cpus node: %s\n", fdt_strerror(cpus_offset));
-		return -EINVAL;
-	}
-
-	/* Add cpus node properties */
-	cpus_node = of_find_node_by_path("/cpus");
-	ret = add_node_props(fdt, cpus_offset, cpus_node);
-	of_node_put(cpus_node);
-	if (ret < 0)
-		return ret;
-
-	/* Loop through all subnodes of cpus and add them to fdt */
-	for_each_node_by_type(dn, "cpu") {
-		cpus_subnode_offset = fdt_add_subnode(fdt, cpus_offset, dn->full_name);
-		if (cpus_subnode_offset < 0) {
-			pr_err("Unable to add %s subnode: %s\n", dn->full_name,
-			       fdt_strerror(cpus_subnode_offset));
-			ret = cpus_subnode_offset;
-			goto out;
-		}
-
-		ret = add_node_props(fdt, cpus_subnode_offset, dn);
-		if (ret < 0)
-			goto out;
-	}
-out:
-	of_node_put(dn);
-	return ret;
-}
-
 static int copy_property(void *fdt, int node_offset, const struct device_node *dn,
 			 const char *propname)
 {
diff --git a/arch/powerpc/kexec/ranges.c b/arch/powerpc/kexec/ranges.c
index 33b780049aaf93..3702b0bdab1410 100644
--- a/arch/powerpc/kexec/ranges.c
+++ b/arch/powerpc/kexec/ranges.c
@@ -20,9 +20,13 @@
 #include <linux/kexec.h>
 #include <linux/of.h>
 #include <linux/slab.h>
+#include <linux/memblock.h>
+#include <linux/crash_core.h>
 #include <asm/sections.h>
 #include <asm/kexec_ranges.h>
+#include <asm/crashdump-ppc64.h>
 
+#if defined(CONFIG_KEXEC_FILE) || defined(CONFIG_CRASH_DUMP)
 /**
  * get_max_nr_ranges - Get the max no. of ranges crash_mem structure
  *                     could hold, given the size allocated for it.
@@ -234,13 +238,16 @@ int add_mem_range(struct crash_mem **mem_ranges, u64 base, u64 size)
 	return __add_mem_range(mem_ranges, base, size);
 }
 
+#endif /* CONFIG_KEXEC_FILE || CONFIG_CRASH_DUMP */
+
+#ifdef CONFIG_KEXEC_FILE
 /**
  * add_tce_mem_ranges - Adds tce-table range to the given memory ranges list.
  * @mem_ranges:         Range list to add the memory range(s) to.
  *
  * Returns 0 on success, negative errno on error.
  */
-int add_tce_mem_ranges(struct crash_mem **mem_ranges)
+static int add_tce_mem_ranges(struct crash_mem **mem_ranges)
 {
 	struct device_node *dn = NULL;
 	int ret = 0;
@@ -279,7 +286,7 @@ int add_tce_mem_ranges(struct crash_mem **mem_ranges)
  *
  * Returns 0 on success, negative errno on error.
  */
-int add_initrd_mem_range(struct crash_mem **mem_ranges)
+static int add_initrd_mem_range(struct crash_mem **mem_ranges)
 {
 	u64 base, end;
 	int ret;
@@ -296,7 +303,6 @@ int add_initrd_mem_range(struct crash_mem **mem_ranges)
 	return ret;
 }
 
-#ifdef CONFIG_PPC_64S_HASH_MMU
 /**
  * add_htab_mem_range - Adds htab range to the given memory ranges list,
  *                      if it exists
@@ -304,14 +310,18 @@ int add_initrd_mem_range(struct crash_mem **mem_ranges)
  *
  * Returns 0 on success, negative errno on error.
  */
-int add_htab_mem_range(struct crash_mem **mem_ranges)
+static int add_htab_mem_range(struct crash_mem **mem_ranges)
 {
+
+#ifdef CONFIG_PPC_64S_HASH_MMU
 	if (!htab_address)
 		return 0;
 
 	return add_mem_range(mem_ranges, __pa(htab_address), htab_size_bytes);
-}
+#else
+	return 0;
 #endif
+}
 
 /**
  * add_kernel_mem_range - Adds kernel text region to the given
@@ -320,18 +330,20 @@ int add_htab_mem_range(struct crash_mem **mem_ranges)
  *
  * Returns 0 on success, negative errno on error.
  */
-int add_kernel_mem_range(struct crash_mem **mem_ranges)
+static int add_kernel_mem_range(struct crash_mem **mem_ranges)
 {
 	return add_mem_range(mem_ranges, 0, __pa(_end));
 }
+#endif /* CONFIG_KEXEC_FILE */
 
+#if defined(CONFIG_KEXEC_FILE) || defined(CONFIG_CRASH_DUMP)
 /**
  * add_rtas_mem_range - Adds RTAS region to the given memory ranges list.
  * @mem_ranges:         Range list to add the memory range to.
  *
  * Returns 0 on success, negative errno on error.
  */
-int add_rtas_mem_range(struct crash_mem **mem_ranges)
+static int add_rtas_mem_range(struct crash_mem **mem_ranges)
 {
 	struct device_node *dn;
 	u32 base, size;
@@ -356,7 +368,7 @@ int add_rtas_mem_range(struct crash_mem **mem_ranges)
  *
  * Returns 0 on success, negative errno on error.
  */
-int add_opal_mem_range(struct crash_mem **mem_ranges)
+static int add_opal_mem_range(struct crash_mem **mem_ranges)
 {
 	struct device_node *dn;
 	u64 base, size;
@@ -374,7 +386,9 @@ int add_opal_mem_range(struct crash_mem **mem_ranges)
 	of_node_put(dn);
 	return ret;
 }
+#endif /* CONFIG_KEXEC_FILE || CONFIG_CRASH_DUMP */
 
+#ifdef CONFIG_KEXEC_FILE
 /**
  * add_reserved_mem_ranges - Adds "/reserved-ranges" regions exported by f/w
  *                           to the given memory ranges list.
@@ -382,7 +396,7 @@ int add_opal_mem_range(struct crash_mem **mem_ranges)
  *
  * Returns 0 on success, negative errno on error.
  */
-int add_reserved_mem_ranges(struct crash_mem **mem_ranges)
+static int add_reserved_mem_ranges(struct crash_mem **mem_ranges)
 {
 	int n_mem_addr_cells, n_mem_size_cells, i, len, cells, ret = 0;
 	struct device_node *root = of_find_node_by_path("/");
@@ -412,3 +426,283 @@ int add_reserved_mem_ranges(struct crash_mem **mem_ranges)
 
 	return ret;
 }
+
+/**
+ * get_reserved_memory_ranges - Get reserve memory ranges. This list includes
+ *                              memory regions that should be added to the
+ *                              memory reserve map to ensure the region is
+ *                              protected from any mischief.
+ * @mem_ranges:                 Range list to add the memory ranges to.
+ *
+ * Returns 0 on success, negative errno on error.
+ */
+int get_reserved_memory_ranges(struct crash_mem **mem_ranges)
+{
+	int ret;
+
+	ret = add_rtas_mem_range(mem_ranges);
+	if (ret)
+		goto out;
+
+	ret = add_tce_mem_ranges(mem_ranges);
+	if (ret)
+		goto out;
+
+	ret = add_reserved_mem_ranges(mem_ranges);
+out:
+	if (ret)
+		pr_err("Failed to setup reserved memory ranges\n");
+	return ret;
+}
+
+/**
+ * get_exclude_memory_ranges - Get exclude memory ranges. This list includes
+ *                             regions like opal/rtas, tce-table, initrd,
+ *                             kernel, htab which should be avoided while
+ *                             setting up kexec load segments.
+ * @mem_ranges:                Range list to add the memory ranges to.
+ *
+ * Returns 0 on success, negative errno on error.
+ */
+int get_exclude_memory_ranges(struct crash_mem **mem_ranges)
+{
+	int ret;
+
+	ret = add_tce_mem_ranges(mem_ranges);
+	if (ret)
+		goto out;
+
+	ret = add_initrd_mem_range(mem_ranges);
+	if (ret)
+		goto out;
+
+	ret = add_htab_mem_range(mem_ranges);
+	if (ret)
+		goto out;
+
+	ret = add_kernel_mem_range(mem_ranges);
+	if (ret)
+		goto out;
+
+	ret = add_rtas_mem_range(mem_ranges);
+	if (ret)
+		goto out;
+
+	ret = add_opal_mem_range(mem_ranges);
+	if (ret)
+		goto out;
+
+	ret = add_reserved_mem_ranges(mem_ranges);
+	if (ret)
+		goto out;
+
+	/* exclude memory ranges should be sorted for easy lookup */
+	sort_memory_ranges(*mem_ranges, true);
+out:
+	if (ret)
+		pr_err("Failed to setup exclude memory ranges\n");
+	return ret;
+}
+
+#ifdef CONFIG_CRASH_DUMP
+/**
+ * get_usable_memory_ranges - Get usable memory ranges. This list includes
+ *                            regions like crashkernel, opal/rtas & tce-table,
+ *                            that kdump kernel could use.
+ * @mem_ranges:               Range list to add the memory ranges to.
+ *
+ * Returns 0 on success, negative errno on error.
+ */
+int get_usable_memory_ranges(struct crash_mem **mem_ranges)
+{
+	int ret;
+
+	/*
+	 * Early boot failure observed on guests when low memory (first memory
+	 * block?) is not added to usable memory. So, add [0, crashk_res.end]
+	 * instead of [crashk_res.start, crashk_res.end] to workaround it.
+	 * Also, crashed kernel's memory must be added to reserve map to
+	 * avoid kdump kernel from using it.
+	 */
+	ret = add_mem_range(mem_ranges, 0, crashk_res.end + 1);
+	if (ret)
+		goto out;
+
+	ret = add_rtas_mem_range(mem_ranges);
+	if (ret)
+		goto out;
+
+	ret = add_opal_mem_range(mem_ranges);
+	if (ret)
+		goto out;
+
+	ret = add_tce_mem_ranges(mem_ranges);
+out:
+	if (ret)
+		pr_err("Failed to setup usable memory ranges\n");
+	return ret;
+}
+#endif /* CONFIG_CRASH_DUMP */
+#endif /* CONFIG_KEXEC_FILE */
+
+#ifdef CONFIG_CRASH_DUMP
+/**
+ * get_crash_memory_ranges - Get crash memory ranges. This list includes
+ *                           first/crashing kernel's memory regions that
+ *                           would be exported via an elfcore.
+ * @mem_ranges:              Range list to add the memory ranges to.
+ *
+ * Returns 0 on success, negative errno on error.
+ */
+int get_crash_memory_ranges(struct crash_mem **mem_ranges)
+{
+	phys_addr_t base, end;
+	struct crash_mem *tmem;
+	u64 i;
+	int ret;
+
+	for_each_mem_range(i, &base, &end) {
+		u64 size = end - base;
+
+		/* Skip backup memory region, which needs a separate entry */
+		if (base == BACKUP_SRC_START) {
+			if (size > BACKUP_SRC_SIZE) {
+				base = BACKUP_SRC_END + 1;
+				size -= BACKUP_SRC_SIZE;
+			} else
+				continue;
+		}
+
+		ret = add_mem_range(mem_ranges, base, size);
+		if (ret)
+			goto out;
+
+		/* Try merging adjacent ranges before reallocation attempt */
+		if ((*mem_ranges)->nr_ranges == (*mem_ranges)->max_nr_ranges)
+			sort_memory_ranges(*mem_ranges, true);
+	}
+
+	/* Reallocate memory ranges if there is no space to split ranges */
+	tmem = *mem_ranges;
+	if (tmem && (tmem->nr_ranges == tmem->max_nr_ranges)) {
+		tmem = realloc_mem_ranges(mem_ranges);
+		if (!tmem)
+			goto out;
+	}
+
+	/* Exclude crashkernel region */
+	ret = crash_exclude_mem_range(tmem, crashk_res.start, crashk_res.end);
+	if (ret)
+		goto out;
+
+	/*
+	 * FIXME: For now, stay in parity with kexec-tools but if RTAS/OPAL
+	 *        regions are exported to save their context at the time of
+	 *        crash, they should actually be backed up just like the
+	 *        first 64K bytes of memory.
+	 */
+	ret = add_rtas_mem_range(mem_ranges);
+	if (ret)
+		goto out;
+
+	ret = add_opal_mem_range(mem_ranges);
+	if (ret)
+		goto out;
+
+	/* create a separate program header for the backup region */
+	ret = add_mem_range(mem_ranges, BACKUP_SRC_START, BACKUP_SRC_SIZE);
+	if (ret)
+		goto out;
+
+	sort_memory_ranges(*mem_ranges, false);
+out:
+	if (ret)
+		pr_err("Failed to setup crash memory ranges\n");
+	return ret;
+}
+
+/**
+ * remove_mem_range - Removes the given memory range from the range list.
+ * @mem_ranges:    Range list to remove the memory range to.
+ * @base:          Base address of the range to remove.
+ * @size:          Size of the memory range to remove.
+ *
+ * (Re)allocates memory, if needed.
+ *
+ * Returns 0 on success, negative errno on error.
+ */
+int remove_mem_range(struct crash_mem **mem_ranges, u64 base, u64 size)
+{
+	u64 end;
+	int ret = 0;
+	unsigned int i;
+	u64 mstart, mend;
+	struct crash_mem *mem_rngs = *mem_ranges;
+
+	if (!size)
+		return 0;
+
+	/*
+	 * Memory range are stored as start and end address, use
+	 * the same format to do remove operation.
+	 */
+	end = base + size - 1;
+
+	for (i = 0; i < mem_rngs->nr_ranges; i++) {
+		mstart = mem_rngs->ranges[i].start;
+		mend = mem_rngs->ranges[i].end;
+
+		/*
+		 * Memory range to remove is not part of this range entry
+		 * in the memory range list
+		 */
+		if (!(base >= mstart && end <= mend))
+			continue;
+
+		/*
+		 * Memory range to remove is equivalent to this entry in the
+		 * memory range list. Remove the range entry from the list.
+		 */
+		if (base == mstart && end == mend) {
+			for (; i < mem_rngs->nr_ranges - 1; i++) {
+				mem_rngs->ranges[i].start = mem_rngs->ranges[i+1].start;
+				mem_rngs->ranges[i].end = mem_rngs->ranges[i+1].end;
+			}
+			mem_rngs->nr_ranges--;
+			goto out;
+		}
+		/*
+		 * Start address of the memory range to remove and the
+		 * current memory range entry in the list is same. Just
+		 * move the start address of the current memory range
+		 * entry in the list to end + 1.
+		 */
+		else if (base == mstart) {
+			mem_rngs->ranges[i].start = end + 1;
+			goto out;
+		}
+		/*
+		 * End address of the memory range to remove and the
+		 * current memory range entry in the list is same.
+		 * Just move the end address of the current memory
+		 * range entry in the list to base - 1.
+		 */
+		else if (end == mend)  {
+			mem_rngs->ranges[i].end = base - 1;
+			goto out;
+		}
+		/*
+		 * Memory range to remove is not at the edge of current
+		 * memory range entry. Split the current memory entry into
+		 * two half.
+		 */
+		else {
+			mem_rngs->ranges[i].end = base - 1;
+			size = mem_rngs->ranges[i].end - end;
+			ret = add_mem_range(mem_ranges, end + 1, size);
+		}
+	}
+out:
+	return ret;
+}
+#endif /* CONFIG_CRASH_DUMP */
diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
index 91ca9a9ee3a2b2..ae5482a2f0ca0e 100644
--- a/arch/x86/include/asm/kexec.h
+++ b/arch/x86/include/asm/kexec.h
@@ -207,18 +207,11 @@ int arch_kimage_file_post_load_cleanup(struct kimage *image);
 extern void kdump_nmi_shootdown_cpus(void);
 
 #ifdef CONFIG_CRASH_HOTPLUG
-void arch_crash_handle_hotplug_event(struct kimage *image);
+void arch_crash_handle_hotplug_event(struct kimage *image, void *arg);
 #define arch_crash_handle_hotplug_event arch_crash_handle_hotplug_event
 
-#ifdef CONFIG_HOTPLUG_CPU
-int arch_crash_hotplug_cpu_support(void);
-#define crash_hotplug_cpu_support arch_crash_hotplug_cpu_support
-#endif
-
-#ifdef CONFIG_MEMORY_HOTPLUG
-int arch_crash_hotplug_memory_support(void);
-#define crash_hotplug_memory_support arch_crash_hotplug_memory_support
-#endif
+int arch_crash_hotplug_support(struct kimage *image, unsigned long kexec_flags);
+#define arch_crash_hotplug_support arch_crash_hotplug_support
 
 unsigned int arch_crash_get_elfcorehdr_size(void);
 #define crash_get_elfcorehdr_size arch_crash_get_elfcorehdr_size
diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
index e74d0c4286c145..f06501445cd981 100644
--- a/arch/x86/kernel/crash.c
+++ b/arch/x86/kernel/crash.c
@@ -402,20 +402,26 @@ int crash_load_segments(struct kimage *image)
 #undef pr_fmt
 #define pr_fmt(fmt) "crash hp: " fmt
 
-/* These functions provide the value for the sysfs crash_hotplug nodes */
-#ifdef CONFIG_HOTPLUG_CPU
-int arch_crash_hotplug_cpu_support(void)
+int arch_crash_hotplug_support(struct kimage *image, unsigned long kexec_flags)
 {
-	return crash_check_update_elfcorehdr();
-}
-#endif
 
-#ifdef CONFIG_MEMORY_HOTPLUG
-int arch_crash_hotplug_memory_support(void)
-{
-	return crash_check_update_elfcorehdr();
-}
+#ifdef CONFIG_KEXEC_FILE
+	if (image->file_mode)
+		return 1;
 #endif
+	/*
+	 * Initially, crash hotplug support for kexec_load was added
+	 * with the KEXEC_UPDATE_ELFCOREHDR flag. Later, this
+	 * functionality was expanded to accommodate multiple kexec
+	 * segment updates, leading to the introduction of the
+	 * KEXEC_CRASH_HOTPLUG_SUPPORT kexec flag bit. Consequently,
+	 * when the kexec tool sends either of these flags, it indicates
+	 * that the required kexec segment (elfcorehdr) is excluded from
+	 * the SHA calculation.
+	 */
+	return (kexec_flags & KEXEC_UPDATE_ELFCOREHDR ||
+		kexec_flags & KEXEC_CRASH_HOTPLUG_SUPPORT);
+}
 
 unsigned int arch_crash_get_elfcorehdr_size(void)
 {
@@ -432,10 +438,12 @@ unsigned int arch_crash_get_elfcorehdr_size(void)
 /**
  * arch_crash_handle_hotplug_event() - Handle hotplug elfcorehdr changes
  * @image: a pointer to kexec_crash_image
+ * @arg: struct memory_notify handler for memory hotplug case and
+ *       NULL for CPU hotplug case.
  *
  * Prepare the new elfcorehdr and replace the existing elfcorehdr.
  */
-void arch_crash_handle_hotplug_event(struct kimage *image)
+void arch_crash_handle_hotplug_event(struct kimage *image, void *arg)
 {
 	void *elfbuf = NULL, *old_elfcorehdr;
 	unsigned long nr_mem_ranges;
diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
index 56fba44ba391ad..c61ecb0c2ae290 100644
--- a/drivers/base/cpu.c
+++ b/drivers/base/cpu.c
@@ -306,7 +306,7 @@ static ssize_t crash_hotplug_show(struct device *dev,
 				     struct device_attribute *attr,
 				     char *buf)
 {
-	return sysfs_emit(buf, "%d\n", crash_hotplug_cpu_support());
+	return sysfs_emit(buf, "%d\n", crash_check_hotplug_support());
 }
 static DEVICE_ATTR_ADMIN_RO(crash_hotplug);
 #endif
diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index c0436f46cfb701..67858eeb92ed28 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -535,7 +535,7 @@ static DEVICE_ATTR_RW(auto_online_blocks);
 static ssize_t crash_hotplug_show(struct device *dev,
 				       struct device_attribute *attr, char *buf)
 {
-	return sysfs_emit(buf, "%d\n", crash_hotplug_memory_support());
+	return sysfs_emit(buf, "%d\n", crash_check_hotplug_support());
 }
 static DEVICE_ATTR_RO(crash_hotplug);
 #endif
diff --git a/include/linux/crash_core.h b/include/linux/crash_core.h
index d33352c2e3865f..44305336314eb4 100644
--- a/include/linux/crash_core.h
+++ b/include/linux/crash_core.h
@@ -37,17 +37,16 @@ static inline void arch_kexec_unprotect_crashkres(void) { }
 
 
 #ifndef arch_crash_handle_hotplug_event
-static inline void arch_crash_handle_hotplug_event(struct kimage *image) { }
+static inline void arch_crash_handle_hotplug_event(struct kimage *image, void *arg) { }
 #endif
 
-int crash_check_update_elfcorehdr(void);
+int crash_check_hotplug_support(void);
 
-#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; }
+#ifndef arch_crash_hotplug_support
+static inline int arch_crash_hotplug_support(struct kimage *image, unsigned long kexec_flags)
+{
+	return 0;
+}
 #endif
 
 #ifndef crash_get_elfcorehdr_size
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index 060835bb82d52f..5b93a5767413a5 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -319,8 +319,10 @@ struct kimage {
 	/* If set, we are using file mode kexec syscall */
 	unsigned int file_mode:1;
 #ifdef CONFIG_CRASH_HOTPLUG
-	/* If set, allow changes to elfcorehdr of kexec_load'd image */
-	unsigned int update_elfcorehdr:1;
+	/* If set, it is safe to update kexec segments that are
+	 * excluded from SHA calculation.
+	 */
+	unsigned int hotplug_support:1;
 #endif
 
 #ifdef ARCH_HAS_KIMAGE_ARCH
@@ -391,9 +393,10 @@ bool kexec_load_permitted(int kexec_image_type);
 
 /* List of defined/legal kexec flags */
 #ifndef CONFIG_KEXEC_JUMP
-#define KEXEC_FLAGS    (KEXEC_ON_CRASH | KEXEC_UPDATE_ELFCOREHDR)
+#define KEXEC_FLAGS    (KEXEC_ON_CRASH | KEXEC_UPDATE_ELFCOREHDR | KEXEC_CRASH_HOTPLUG_SUPPORT)
 #else
-#define KEXEC_FLAGS    (KEXEC_ON_CRASH | KEXEC_PRESERVE_CONTEXT | KEXEC_UPDATE_ELFCOREHDR)
+#define KEXEC_FLAGS    (KEXEC_ON_CRASH | KEXEC_PRESERVE_CONTEXT | KEXEC_UPDATE_ELFCOREHDR | \
+			KEXEC_CRASH_HOTPLUG_SUPPORT)
 #endif
 
 /* List of defined/legal kexec file flags */
diff --git a/include/uapi/linux/kexec.h b/include/uapi/linux/kexec.h
index c17bb096ea6857..5ae1741ea8ea07 100644
--- a/include/uapi/linux/kexec.h
+++ b/include/uapi/linux/kexec.h
@@ -13,6 +13,7 @@
 #define KEXEC_ON_CRASH		0x00000001
 #define KEXEC_PRESERVE_CONTEXT	0x00000002
 #define KEXEC_UPDATE_ELFCOREHDR	0x00000004
+#define KEXEC_CRASH_HOTPLUG_SUPPORT 0x00000008
 #define KEXEC_ARCH_MASK		0xffff0000
 
 /*
diff --git a/kernel/crash_core.c b/kernel/crash_core.c
index 78b5dc7cee3ab7..394db3ebe83535 100644
--- a/kernel/crash_core.c
+++ b/kernel/crash_core.c
@@ -493,10 +493,10 @@ static DEFINE_MUTEX(__crash_hotplug_lock);
 
 /*
  * This routine utilized when the crash_hotplug sysfs node is read.
- * It reflects the kernel's ability/permission to update the crash
- * elfcorehdr directly.
+ * It reflects the kernel's ability/permission to update the kdump
+ * image directly.
  */
-int crash_check_update_elfcorehdr(void)
+int crash_check_hotplug_support(void)
 {
 	int rc = 0;
 
@@ -508,10 +508,7 @@ int crash_check_update_elfcorehdr(void)
 		return 0;
 	}
 	if (kexec_crash_image) {
-		if (kexec_crash_image->file_mode)
-			rc = 1;
-		else
-			rc = kexec_crash_image->update_elfcorehdr;
+		rc = kexec_crash_image->hotplug_support;
 	}
 	/* Release lock now that update complete */
 	kexec_unlock();
@@ -534,7 +531,7 @@ int crash_check_update_elfcorehdr(void)
  * list of segments it checks (since the elfcorehdr changes and thus
  * would require an update to purgatory itself to update the digest).
  */
-static void crash_handle_hotplug_event(unsigned int hp_action, unsigned int cpu)
+static void crash_handle_hotplug_event(unsigned int hp_action, unsigned int cpu, void *arg)
 {
 	struct kimage *image;
 
@@ -552,8 +549,8 @@ static void crash_handle_hotplug_event(unsigned int hp_action, unsigned int cpu)
 
 	image = kexec_crash_image;
 
-	/* Check that updating elfcorehdr is permitted */
-	if (!(image->file_mode || image->update_elfcorehdr))
+	/* Check that kexec segments update is permitted */
+	if (!image->hotplug_support)
 		goto out;
 
 	if (hp_action == KEXEC_CRASH_HP_ADD_CPU ||
@@ -596,7 +593,7 @@ static void crash_handle_hotplug_event(unsigned int hp_action, unsigned int cpu)
 	image->hp_action = hp_action;
 
 	/* Now invoke arch-specific update handler */
-	arch_crash_handle_hotplug_event(image);
+	arch_crash_handle_hotplug_event(image, arg);
 
 	/* No longer handling a hotplug event */
 	image->hp_action = KEXEC_CRASH_HP_NONE;
@@ -612,17 +609,17 @@ out:
 	crash_hotplug_unlock();
 }
 
-static int crash_memhp_notifier(struct notifier_block *nb, unsigned long val, void *v)
+static int crash_memhp_notifier(struct notifier_block *nb, unsigned long val, void *arg)
 {
 	switch (val) {
 	case MEM_ONLINE:
 		crash_handle_hotplug_event(KEXEC_CRASH_HP_ADD_MEMORY,
-			KEXEC_CRASH_HP_INVALID_CPU);
+			KEXEC_CRASH_HP_INVALID_CPU, arg);
 		break;
 
 	case MEM_OFFLINE:
 		crash_handle_hotplug_event(KEXEC_CRASH_HP_REMOVE_MEMORY,
-			KEXEC_CRASH_HP_INVALID_CPU);
+			KEXEC_CRASH_HP_INVALID_CPU, arg);
 		break;
 	}
 	return NOTIFY_OK;
@@ -635,13 +632,13 @@ static struct notifier_block crash_memhp_nb = {
 
 static int crash_cpuhp_online(unsigned int cpu)
 {
-	crash_handle_hotplug_event(KEXEC_CRASH_HP_ADD_CPU, cpu);
+	crash_handle_hotplug_event(KEXEC_CRASH_HP_ADD_CPU, cpu, NULL);
 	return 0;
 }
 
 static int crash_cpuhp_offline(unsigned int cpu)
 {
-	crash_handle_hotplug_event(KEXEC_CRASH_HP_REMOVE_CPU, cpu);
+	crash_handle_hotplug_event(KEXEC_CRASH_HP_REMOVE_CPU, cpu, NULL);
 	return 0;
 }
 
diff --git a/kernel/kexec.c b/kernel/kexec.c
index bab542fc1463d2..a6b3f96bb50c87 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -135,8 +135,8 @@ static int do_kexec_load(unsigned long entry, unsigned long nr_segments,
 		image->preserve_context = 1;
 
 #ifdef CONFIG_CRASH_HOTPLUG
-	if (flags & KEXEC_UPDATE_ELFCOREHDR)
-		image->update_elfcorehdr = 1;
+	if ((flags & KEXEC_ON_CRASH) && arch_crash_hotplug_support(image, flags))
+		image->hotplug_support = 1;
 #endif
 
 	ret = machine_kexec_prepare(image);
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index 2d1db05fbf04f3..3d64290d24c9a2 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -376,6 +376,11 @@ SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd,
 	if (ret)
 		goto out;
 
+#ifdef CONFIG_CRASH_HOTPLUG
+	if ((flags & KEXEC_FILE_ON_CRASH) && arch_crash_hotplug_support(image, flags))
+		image->hotplug_support = 1;
+#endif
+
 	ret = machine_kexec_prepare(image);
 	if (ret)
 		goto out;