x86/kprobes: Fix crash when probing CS CALL instructionsgrafted

When using eBPF to probe CS CALL instructions within a function,
a crash can be triggered.

The eBPF tool probes offset 257 of the __hrtimer_run_queues()
function:

<__hrtimer_run_queues+249>:  nopl   0x0(%rax,%rax,1)
<__hrtimer_run_queues+254>:  mov    %r14,%rdi
<__hrtimer_run_queues+257>:  cs call <__x86_indirect_thunk_r12>
<__hrtimer_run_queues+263>:  mov    %eax,%r12d
<__hrtimer_run_queues+266>:  xchg   %ax,%ax
<__hrtimer_run_queues+268>:  mov    %r13,%rdi

Which triggers this crash:

  BUG: unable to handle page fault for address: 00000000000f41c9
  #PF: supervisor write access in kernel mode
  #PF: error_code(0x0002) - not-present page
  PGD 0 P4D 0
  Oops: 0002 [#1] SMP NOPTI
  CPU: 1 PID: 0 Comm: swapper/1 Kdump: loaded Tainted: P
  RIP: 0010:__hrtimer_run_queues+0x106/0x230

Note that __hrtimer_run_queues+0x106 is __hrtimer_run_queues+262, which is
at the 6th byte of the above CS CALL instruction. Since the CS CALL
instruction occupies 6 bytes, the exception occurred in the middle of that
call instruction.

The root cause is that when using eBPF tools to probe in the middle of a
function, a kprobe with INT3 is used as the underlying implementation.

During single-step emulation of the original CALL instruction,
int3_emulate_call() assumes that the probed CALL instruction is 5 bytes
long. However, the actual CS-prefixed CALL instruction occupies 6 bytes,
so it constructs an incorrect exception return address. When the CPU
returns from the kprobe handler, the next instruction to be executed is at
the address of the last byte of that CS CALL instruction. Coincidentally,
starting from that address, the CPU fetches and decodes a completely
different instruction, which ultimately triggers a kernel crash.

Fix the issue by using the actual instruction length obtained from
the instruction decoder when constructing the exception return
address, rather than relying on the hardcoded CALL_INSN_SIZE macro.

[ mingo: Refined the changelog ]

Fixes: 6256e668b7af ("x86/kprobes: Use int3 instead of debug trap for single-step")
Suggested-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Jinke Han <jinkehan@didiglobal.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://patch.msgid.link/20260908073742.GA10517@didi-ThinkCentre-M920t-N000

11 files changed, 3824 insertions, 0 deletions

diff --git a/arch/powerpc/kexec/Makefile b/arch/powerpc/kexec/Makefile
new file mode 100644
index 000000000..ec7a0eed7
--- /dev/null
+++ b/arch/powerpc/kexec/Makefile
@@ -0,0 +1,19 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for the linux kernel.
+#
+
+obj-y				+= core.o core_$(BITS).o ranges.o
+
+obj-$(CONFIG_PPC32)		+= relocate_32.o
+
+obj-$(CONFIG_KEXEC_FILE)	+= file_load.o file_load_$(BITS).o elf_$(BITS).o
+obj-$(CONFIG_VMCORE_INFO)	+= vmcore_info.o
+obj-$(CONFIG_CRASH_DUMP)	+= crash.o
+
+# Disable GCOV, KCOV & sanitizers in odd or sensitive code
+GCOV_PROFILE_core_$(BITS).o := n
+KCOV_INSTRUMENT_core_$(BITS).o := n
+UBSAN_SANITIZE_core_$(BITS).o := n
+KASAN_SANITIZE_core.o := n
+KASAN_SANITIZE_core_$(BITS).o := n
diff --git a/arch/powerpc/kexec/core.c b/arch/powerpc/kexec/core.c
new file mode 100644
index 000000000..dc44f11be
--- /dev/null
+++ b/arch/powerpc/kexec/core.c
@@ -0,0 +1,227 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Code to handle transition of Linux booting another kernel.
+ *
+ * Copyright (C) 2002-2003 Eric Biederman  <ebiederm@xmission.com>
+ * GameCube/ppc32 port Copyright (C) 2004 Albert Herranz
+ * Copyright (C) 2005 IBM Corporation.
+ */
+
+#include <linux/kexec.h>
+#include <linux/reboot.h>
+#include <linux/threads.h>
+#include <linux/memblock.h>
+#include <linux/of.h>
+#include <linux/irq.h>
+#include <linux/ftrace.h>
+
+#include <asm/kdump.h>
+#include <asm/machdep.h>
+#include <asm/pgalloc.h>
+#include <asm/sections.h>
+#include <asm/setup.h>
+#include <asm/firmware.h>
+
+#define cpu_to_be_ulong __PASTE(cpu_to_be, BITS_PER_LONG)
+#define __be_word __PASTE(__be, BITS_PER_LONG)
+
+#ifdef CONFIG_CRASH_DUMP
+void machine_crash_shutdown(struct pt_regs *regs)
+{
+	default_machine_crash_shutdown(regs);
+}
+#endif
+
+void machine_kexec_cleanup(struct kimage *image)
+{
+}
+
+/*
+ * Do not allocate memory (or fail in any way) in machine_kexec().
+ * We are past the point of no return, committed to rebooting now.
+ */
+void machine_kexec(struct kimage *image)
+{
+	int save_ftrace_enabled;
+
+	save_ftrace_enabled = __ftrace_enabled_save();
+	this_cpu_disable_ftrace();
+
+	if (ppc_md.machine_kexec)
+		ppc_md.machine_kexec(image);
+	else
+		default_machine_kexec(image);
+
+	this_cpu_enable_ftrace();
+	__ftrace_enabled_restore(save_ftrace_enabled);
+
+	/* Fall back to normal restart if we're still alive. */
+	machine_restart(NULL);
+	for(;;);
+}
+
+#ifdef CONFIG_CRASH_RESERVE
+
+static unsigned long long crashk_cma_size;
+
+static unsigned long long __init get_crash_base(unsigned long long crash_base)
+{
+
+#ifndef CONFIG_NONSTATIC_KERNEL
+	if (crash_base != KDUMP_KERNELBASE)
+		printk("Crash kernel location must be 0x%x\n",
+				KDUMP_KERNELBASE);
+
+	return KDUMP_KERNELBASE;
+#else
+	unsigned long long crash_base_align;
+
+	if (!crash_base) {
+#ifdef CONFIG_PPC64
+		/*
+		 * On the LPAR platform place the crash kernel to mid of
+		 * RMA size (max. of 512MB) to ensure the crash kernel
+		 * gets enough space to place itself and some stack to be
+		 * in the first segment. At the same time normal kernel
+		 * also get enough space to allocate memory for essential
+		 * system resource in the first segment. Keep the crash
+		 * kernel starts at 128MB offset on other platforms.
+		 */
+		if (firmware_has_feature(FW_FEATURE_LPAR))
+			crash_base = min_t(u64, ppc64_rma_size / 2, SZ_512M);
+		else
+			crash_base = min_t(u64, ppc64_rma_size / 2, SZ_128M);
+#else
+		crash_base = KDUMP_KERNELBASE;
+#endif
+	}
+
+	crash_base_align = PAGE_ALIGN(crash_base);
+	if (crash_base != crash_base_align)
+		pr_warn("Crash kernel base must be aligned to 0x%lx\n", PAGE_SIZE);
+
+	return crash_base_align;
+#endif
+}
+
+void __init arch_reserve_crashkernel(void)
+{
+	unsigned long long crash_size, crash_base, crash_end;
+	unsigned long long kernel_start, kernel_size;
+	unsigned long long total_mem_sz;
+	int ret;
+
+	total_mem_sz = memory_limit ? memory_limit : memblock_phys_mem_size();
+
+	/* use common parsing */
+	ret = parse_crashkernel(boot_command_line, total_mem_sz, &crash_size,
+				&crash_base, NULL, &crashk_cma_size, NULL);
+
+	if (ret)
+		return;
+
+	crash_base = get_crash_base(crash_base);
+	crash_end = crash_base + crash_size - 1;
+
+	kernel_start = __pa(_stext);
+	kernel_size = _end - _stext;
+
+	/* The crash region must not overlap the current kernel */
+	if ((kernel_start + kernel_size > crash_base) && (kernel_start <= crash_end)) {
+		pr_warn("Crash kernel can not overlap current kernel\n");
+		return;
+	}
+
+	reserve_crashkernel_generic(crash_size, crash_base, 0, false);
+}
+
+void __init kdump_cma_reserve(void)
+{
+	if (crashk_cma_size)
+		reserve_crashkernel_cma(crashk_cma_size);
+}
+
+int __init overlaps_crashkernel(unsigned long start, unsigned long size)
+{
+	return (start + size) > crashk_res.start && start <= crashk_res.end;
+}
+
+/* Values we need to export to the second kernel via the device tree. */
+static __be_word crashk_base;
+static __be_word crashk_size;
+static __be_word mem_limit;
+
+static struct property crashk_base_prop = {
+	.name = "linux,crashkernel-base",
+	.length = sizeof(__be_word),
+	.value = &crashk_base
+};
+
+static struct property crashk_size_prop = {
+	.name = "linux,crashkernel-size",
+	.length = sizeof(__be_word),
+	.value = &crashk_size,
+};
+
+static struct property memory_limit_prop = {
+	.name = "linux,memory-limit",
+	.length = sizeof(__be_word),
+	.value = &mem_limit,
+};
+
+static void __init export_crashk_values(struct device_node *node)
+{
+	/* There might be existing crash kernel properties, but we can't
+	 * be sure what's in them, so remove them. */
+	of_remove_property(node, of_find_property(node,
+				"linux,crashkernel-base", NULL));
+	of_remove_property(node, of_find_property(node,
+				"linux,crashkernel-size", NULL));
+
+	if (crashk_res.start != 0) {
+		crashk_base = cpu_to_be_ulong(crashk_res.start),
+		of_add_property(node, &crashk_base_prop);
+		crashk_size = cpu_to_be_ulong(resource_size(&crashk_res));
+		of_add_property(node, &crashk_size_prop);
+	}
+
+	/*
+	 * memory_limit is required by the kexec-tools to limit the
+	 * crash regions to the actual memory used.
+	 */
+	mem_limit = cpu_to_be_ulong(memory_limit);
+	of_update_property(node, &memory_limit_prop);
+}
+#endif /* CONFIG_CRASH_RESERVE */
+
+static __be_word kernel_end;
+
+static struct property kernel_end_prop = {
+	.name = "linux,kernel-end",
+	.length = sizeof(__be_word),
+	.value = &kernel_end,
+};
+
+static int __init kexec_setup(void)
+{
+	struct device_node *node;
+
+	node = of_find_node_by_path("/chosen");
+	if (!node)
+		return -ENOENT;
+
+	/* remove any stale properties so ours can be found */
+	of_remove_property(node, of_find_property(node, kernel_end_prop.name,
+						  NULL));
+
+	/* information needed by userspace when using default_machine_kexec */
+	kernel_end = cpu_to_be_ulong(__pa(_end));
+	of_add_property(node, &kernel_end_prop);
+
+#ifdef CONFIG_CRASH_RESERVE
+	export_crashk_values(node);
+#endif
+	of_node_put(node);
+	return 0;
+}
+late_initcall(kexec_setup);
diff --git a/arch/powerpc/kexec/core_32.c b/arch/powerpc/kexec/core_32.c
new file mode 100644
index 000000000..deb28eb44
--- /dev/null
+++ b/arch/powerpc/kexec/core_32.c
@@ -0,0 +1,70 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * PPC32 code to handle Linux booting another kernel.
+ *
+ * Copyright (C) 2002-2003 Eric Biederman  <ebiederm@xmission.com>
+ * GameCube/ppc32 port Copyright (C) 2004 Albert Herranz
+ * Copyright (C) 2005 IBM Corporation.
+ */
+
+#include <linux/irq.h>
+#include <linux/kexec.h>
+#include <linux/mm.h>
+#include <linux/string.h>
+#include <asm/cacheflush.h>
+#include <asm/hw_irq.h>
+#include <asm/io.h>
+
+typedef void (*relocate_new_kernel_t)(
+				unsigned long indirection_page,
+				unsigned long reboot_code_buffer,
+				unsigned long start_address) __noreturn;
+
+/*
+ * This is a generic machine_kexec function suitable at least for
+ * non-OpenFirmware embedded platforms.
+ * It merely copies the image relocation code to the control page and
+ * jumps to it.
+ * A platform specific function may just call this one.
+ */
+void default_machine_kexec(struct kimage *image)
+{
+	extern const unsigned int relocate_new_kernel_size;
+	unsigned long page_list;
+	unsigned long reboot_code_buffer, reboot_code_buffer_phys;
+	relocate_new_kernel_t rnk;
+
+	/* Interrupts aren't acceptable while we reboot */
+	local_irq_disable();
+
+	/* mask each interrupt so we are in a more sane state for the
+	 * kexec kernel */
+	machine_kexec_mask_interrupts();
+
+	page_list = image->head;
+
+	/* we need both effective and real address here */
+	reboot_code_buffer =
+			(unsigned long)page_address(image->control_code_page);
+	reboot_code_buffer_phys = virt_to_phys((void *)reboot_code_buffer);
+
+	/* copy our kernel relocation code to the control code page */
+	memcpy((void *)reboot_code_buffer, relocate_new_kernel,
+						relocate_new_kernel_size);
+
+	flush_icache_range(reboot_code_buffer,
+				reboot_code_buffer + KEXEC_CONTROL_PAGE_SIZE);
+	printk(KERN_INFO "Bye!\n");
+
+	if (!IS_ENABLED(CONFIG_PPC_85xx) && !IS_ENABLED(CONFIG_44x))
+		relocate_new_kernel(page_list, reboot_code_buffer_phys, image->start);
+
+	/* now call it */
+	rnk = (relocate_new_kernel_t) reboot_code_buffer;
+	(*rnk)(page_list, reboot_code_buffer_phys, image->start);
+}
+
+int machine_kexec_prepare(struct kimage *image)
+{
+	return 0;
+}
diff --git a/arch/powerpc/kexec/core_64.c b/arch/powerpc/kexec/core_64.c
new file mode 100644
index 000000000..58c13a59b
--- /dev/null
+++ b/arch/powerpc/kexec/core_64.c
@@ -0,0 +1,561 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * PPC64 code to handle Linux booting another kernel.
+ *
+ * Copyright (C) 2004-2005, IBM Corp.
+ *
+ * Created by: Milton D Miller II
+ */
+
+
+#include <linux/kexec.h>
+#include <linux/smp.h>
+#include <linux/thread_info.h>
+#include <linux/init_task.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/cpu.h>
+#include <linux/hardirq.h>
+#include <linux/of.h>
+#include <linux/libfdt.h>
+
+#include <asm/page.h>
+#include <asm/current.h>
+#include <asm/machdep.h>
+#include <asm/cacheflush.h>
+#include <asm/firmware.h>
+#include <asm/paca.h>
+#include <asm/mmu.h>
+#include <asm/sections.h>	/* _end */
+#include <asm/setup.h>
+#include <asm/smp.h>
+#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)
+{
+	int i;
+	unsigned long begin, end;	/* limits of segment */
+	unsigned long low, high;	/* limits of blocked memory range */
+	struct device_node *node;
+	const unsigned long *basep;
+	const unsigned int *sizep;
+
+	/*
+	 * Since we use the kernel fault handlers and paging code to
+	 * handle the virtual mode, we must make sure no destination
+	 * overlaps kernel static data or bss.
+	 */
+	for (i = 0; i < image->nr_segments; i++)
+		if (image->segment[i].mem < __pa(_end))
+			return -ETXTBSY;
+
+	/* We also should not overwrite the tce tables */
+	for_each_node_by_type(node, "pci") {
+		basep = of_get_property(node, "linux,tce-base", NULL);
+		sizep = of_get_property(node, "linux,tce-size", NULL);
+		if (basep == NULL || sizep == NULL)
+			continue;
+
+		low = *basep;
+		high = low + (*sizep);
+
+		for (i = 0; i < image->nr_segments; i++) {
+			begin = image->segment[i].mem;
+			end = begin + image->segment[i].memsz;
+
+			if ((begin < high) && (end > low)) {
+				of_node_put(node);
+				return -ETXTBSY;
+			}
+		}
+	}
+
+	return 0;
+}
+
+/* Called during kexec sequence with MMU off */
+static notrace void copy_segments(unsigned long ind)
+{
+	unsigned long entry;
+	unsigned long *ptr;
+	void *dest;
+	void *addr;
+
+	/*
+	 * We rely on kexec_load to create a lists that properly
+	 * initializes these pointers before they are used.
+	 * We will still crash if the list is wrong, but at least
+	 * the compiler will be quiet.
+	 */
+	ptr = NULL;
+	dest = NULL;
+
+	for (entry = ind; !(entry & IND_DONE); entry = *ptr++) {
+		addr = __va(entry & PAGE_MASK);
+
+		switch (entry & IND_FLAGS) {
+		case IND_DESTINATION:
+			dest = addr;
+			break;
+		case IND_INDIRECTION:
+			ptr = addr;
+			break;
+		case IND_SOURCE:
+			copy_page(dest, addr);
+			dest += PAGE_SIZE;
+		}
+	}
+}
+
+/* Called during kexec sequence with MMU off */
+notrace void kexec_copy_flush(struct kimage *image)
+{
+	long i, nr_segments = image->nr_segments;
+	struct  kexec_segment ranges[KEXEC_SEGMENT_MAX];
+
+	/* save the ranges on the stack to efficiently flush the icache */
+	memcpy(ranges, image->segment, sizeof(ranges));
+
+	/*
+	 * After this call we may not use anything allocated in dynamic
+	 * memory, including *image.
+	 *
+	 * Only globals and the stack are allowed.
+	 */
+	copy_segments(image->head);
+
+	/*
+	 * we need to clear the icache for all dest pages sometime,
+	 * including ones that were in place on the original copy
+	 */
+	for (i = 0; i < nr_segments; i++)
+		flush_icache_range((unsigned long)__va(ranges[i].mem),
+			(unsigned long)__va(ranges[i].mem + ranges[i].memsz));
+}
+
+#ifdef CONFIG_SMP
+
+static int kexec_all_irq_disabled = 0;
+
+static void kexec_smp_down(void *arg)
+{
+	local_irq_disable();
+	hard_irq_disable();
+
+	mb(); /* make sure our irqs are disabled before we say they are */
+	get_paca()->kexec_state = KEXEC_STATE_IRQS_OFF;
+	while(kexec_all_irq_disabled == 0)
+		cpu_relax();
+	mb(); /* make sure all irqs are disabled before this */
+	hw_breakpoint_disable();
+	/*
+	 * Now every CPU has IRQs off, we can clear out any pending
+	 * IPIs and be sure that no more will come in after this.
+	 */
+	if (ppc_md.kexec_cpu_down)
+		ppc_md.kexec_cpu_down(0, 1);
+
+	reset_sprs();
+
+	kexec_smp_wait();
+	/* NOTREACHED */
+}
+
+static void kexec_prepare_cpus_wait(int wait_state)
+{
+	int my_cpu, i, notified=-1;
+
+	hw_breakpoint_disable();
+	my_cpu = raw_smp_processor_id();
+	/* Make sure each CPU has at least made it to the state we need.
+	 *
+	 * FIXME: There is a (slim) chance of a problem if not all of the CPUs
+	 * are correctly onlined.  If somehow we start a CPU on boot with RTAS
+	 * start-cpu, but somehow that CPU doesn't write callin_cpu_map[] in
+	 * time, the boot CPU will timeout.  If it does eventually execute
+	 * stuff, the secondary will start up (paca_ptrs[]->cpu_start was
+	 * written) and get into a peculiar state.
+	 * If the platform supports smp_ops->take_timebase(), the secondary CPU
+	 * will probably be spinning in there.  If not (i.e. pseries), the
+	 * secondary will continue on and try to online itself/idle/etc. If it
+	 * survives that, we need to find these
+	 * possible-but-not-online-but-should-be CPUs and chaperone them into
+	 * kexec_smp_wait().
+	 */
+	for_each_online_cpu(i) {
+		if (i == my_cpu)
+			continue;
+
+		while (paca_ptrs[i]->kexec_state < wait_state) {
+			barrier();
+			if (i != notified) {
+				printk(KERN_INFO "kexec: waiting for cpu %d "
+				       "(physical %d) to enter %i state\n",
+				       i, paca_ptrs[i]->hw_cpu_id, wait_state);
+				notified = i;
+			}
+		}
+	}
+	mb();
+}
+
+
+/*
+ * The add_cpu() call in wake_offline_cpus() can fail as cpu_bootable()
+ * returns false for CPUs that fail the cpu_smt_thread_allowed() check
+ * or non primary threads if SMT is disabled. Re-enable SMT and set the
+ * number of SMT threads to threads per core.
+ */
+static void kexec_smt_reenable(void)
+{
+#if defined(CONFIG_SMP) && defined(CONFIG_HOTPLUG_SMT)
+	lock_device_hotplug();
+	cpu_smt_num_threads = threads_per_core;
+	cpu_smt_control = CPU_SMT_ENABLED;
+	unlock_device_hotplug();
+#endif
+}
+
+/*
+ * We need to make sure each present CPU is online.  The next kernel will scan
+ * the device tree and assume primary threads are online and query secondary
+ * threads via RTAS to online them if required.  If we don't online primary
+ * threads, they will be stuck.  However, we also online secondary threads as we
+ * may be using 'cede offline'.  In this case RTAS doesn't see the secondary
+ * threads as offline -- and again, these CPUs will be stuck.
+ *
+ * So, we online all CPUs that should be running, including secondary threads.
+ */
+static void wake_offline_cpus(void)
+{
+	int cpu = 0;
+
+	kexec_smt_reenable();
+
+	for_each_present_cpu(cpu) {
+		if (!cpu_online(cpu)) {
+			printk(KERN_INFO "kexec: Waking offline cpu %d.\n",
+			       cpu);
+			WARN_ON(add_cpu(cpu));
+		}
+	}
+}
+
+static void kexec_prepare_cpus(void)
+{
+	wake_offline_cpus();
+	smp_call_function(kexec_smp_down, NULL, /* wait */0);
+	local_irq_disable();
+	hard_irq_disable();
+
+	mb(); /* make sure IRQs are disabled before we say they are */
+	get_paca()->kexec_state = KEXEC_STATE_IRQS_OFF;
+
+	kexec_prepare_cpus_wait(KEXEC_STATE_IRQS_OFF);
+	/* we are sure every CPU has IRQs off at this point */
+	kexec_all_irq_disabled = 1;
+
+	/*
+	 * Before removing MMU mappings make sure all CPUs have entered real
+	 * mode:
+	 */
+	kexec_prepare_cpus_wait(KEXEC_STATE_REAL_MODE);
+
+	/* after we tell the others to go down */
+	if (ppc_md.kexec_cpu_down)
+		ppc_md.kexec_cpu_down(0, 0);
+}
+
+#else /* ! SMP */
+
+static void kexec_prepare_cpus(void)
+{
+	/*
+	 * move the secondarys to us so that we can copy
+	 * the new kernel 0-0x100 safely
+	 *
+	 * do this if kexec in setup.c ?
+	 *
+	 * We need to release the cpus if we are ever going from an
+	 * UP to an SMP kernel.
+	 */
+	smp_release_cpus();
+	if (ppc_md.kexec_cpu_down)
+		ppc_md.kexec_cpu_down(0, 0);
+	local_irq_disable();
+	hard_irq_disable();
+}
+
+#endif /* SMP */
+
+/*
+ * kexec thread structure and stack.
+ *
+ * We need to make sure that this is 16384-byte aligned due to the
+ * way process stacks are handled.  It also must be statically allocated
+ * or allocated as part of the kimage, because everything else may be
+ * overwritten when we copy the kexec image.  We piggyback on the
+ * "init_task" linker section here to statically allocate a stack.
+ *
+ * We could use a smaller stack if we don't care about anything using
+ * current, but that audit has not been performed.
+ */
+static union thread_union kexec_stack = { };
+
+/*
+ * For similar reasons to the stack above, the kexecing CPU needs to be on a
+ * static PACA; we switch to kexec_paca.
+ */
+static struct paca_struct kexec_paca;
+
+/* Our assembly helper, in misc_64.S */
+extern void kexec_sequence(void *newstack, unsigned long start,
+			   void *image, void *control,
+			   void (*clear_all)(void),
+			   bool copy_with_mmu_off) __noreturn;
+
+/* too late to fail here */
+void default_machine_kexec(struct kimage *image)
+{
+	bool copy_with_mmu_off;
+
+	/* prepare control code if any */
+
+	/*
+        * If the kexec boot is the normal one, need to shutdown other cpus
+        * into our wait loop and quiesce interrupts.
+        * Otherwise, in the case of crashed mode (crashing_cpu >= 0),
+        * stopping other CPUs and collecting their pt_regs is done before
+        * using debugger IPI.
+        */
+
+	if (!kdump_in_progress())
+		kexec_prepare_cpus();
+
+#ifdef CONFIG_PPC_PSERIES
+	/*
+	 * This must be done after other CPUs have shut down, otherwise they
+	 * could execute the 'scv' instruction, which is not supported with
+	 * reloc disabled (see configure_exceptions()).
+	 */
+	if (firmware_has_feature(FW_FEATURE_SET_MODE))
+		pseries_disable_reloc_on_exc();
+#endif
+
+	printk("kexec: Starting switchover sequence.\n");
+
+	/* switch to a staticly allocated stack.  Based on irq stack code.
+	 * We setup preempt_count to avoid using VMX in memcpy.
+	 * XXX: the task struct will likely be invalid once we do the copy!
+	 */
+	current_thread_info()->flags = 0;
+	current_thread_info()->preempt_count = HARDIRQ_OFFSET;
+
+	/* We need a static PACA, too; copy this CPU's PACA over and switch to
+	 * it. Also poison per_cpu_offset and NULL lppaca to catch anyone using
+	 * non-static data.
+	 */
+	memcpy(&kexec_paca, get_paca(), sizeof(struct paca_struct));
+	kexec_paca.data_offset = 0xedeaddeadeeeeeeeUL;
+#ifdef CONFIG_PPC_PSERIES
+	kexec_paca.lppaca_ptr = NULL;
+#endif
+
+	if (is_secure_guest() && !(image->preserve_context ||
+				   image->type == KEXEC_TYPE_CRASH)) {
+		uv_unshare_all_pages();
+		printk("kexec: Unshared all shared pages.\n");
+	}
+
+	paca_ptrs[kexec_paca.paca_index] = &kexec_paca;
+
+	setup_paca(&kexec_paca);
+
+	/*
+	 * The lppaca should be unregistered at this point so the HV won't
+	 * touch it. In the case of a crash, none of the lppacas are
+	 * unregistered so there is not much we can do about it here.
+	 */
+
+	/*
+	 * On Book3S, the copy must happen with the MMU off if we are either
+	 * using Radix page tables or we are not in an LPAR since we can
+	 * overwrite the page tables while copying.
+	 *
+	 * In an LPAR, we keep the MMU on otherwise we can't access beyond
+	 * the RMA. On BookE there is no real MMU off mode, so we have to
+	 * keep it enabled as well (but then we have bolted TLB entries).
+	 */
+#ifdef CONFIG_PPC_BOOK3E_64
+	copy_with_mmu_off = false;
+#else
+	copy_with_mmu_off = radix_enabled() ||
+		!(firmware_has_feature(FW_FEATURE_LPAR) ||
+		  firmware_has_feature(FW_FEATURE_PS3_LV1));
+#endif
+
+	/* Some things are best done in assembly.  Finding globals with
+	 * a toc is easier in C, so pass in what we can.
+	 */
+	kexec_sequence(&kexec_stack, image->start, image,
+		       page_address(image->control_code_page),
+		       mmu_cleanup_all, copy_with_mmu_off);
+	/* NOTREACHED */
+}
+
+#ifdef CONFIG_PPC_64S_HASH_MMU
+/* Values we need to export to the second kernel via the device tree. */
+static __be64 htab_base;
+static __be64 htab_size;
+
+static struct property htab_base_prop = {
+	.name = "linux,htab-base",
+	.length = sizeof(unsigned long),
+	.value = &htab_base,
+};
+
+static struct property htab_size_prop = {
+	.name = "linux,htab-size",
+	.length = sizeof(unsigned long),
+	.value = &htab_size,
+};
+
+static int __init export_htab_values(void)
+{
+	struct device_node *node;
+
+	/* On machines with no htab htab_address is NULL */
+	if (!htab_address)
+		return -ENODEV;
+
+	node = of_find_node_by_path("/chosen");
+	if (!node)
+		return -ENODEV;
+
+	/* remove any stale properties so ours can be found */
+	of_remove_property(node, of_find_property(node, htab_base_prop.name, NULL));
+	of_remove_property(node, of_find_property(node, htab_size_prop.name, NULL));
+
+	htab_base = cpu_to_be64(__pa(htab_address));
+	of_add_property(node, &htab_base_prop);
+	htab_size = cpu_to_be64(htab_size_bytes);
+	of_add_property(node, &htab_size_prop);
+
+	of_node_put(node);
+	return 0;
+}
+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.
+ *
+ * Note: expecting no subnodes under /cpus/<node> with device_type == "cpu".
+ * If this changes, update this function to include them.
+ */
+int update_cpus_node(void *fdt)
+{
+	int prev_node_offset;
+	const char *device_type;
+	const struct fdt_property *prop;
+	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;
+	}
+
+	prev_node_offset = cpus_offset;
+	/* Delete sub-nodes of /cpus node with device_type == "cpu" */
+	for (cpus_subnode_offset = fdt_first_subnode(fdt, cpus_offset); cpus_subnode_offset >= 0;) {
+		/* Ignore nodes that do not have a device_type property or device_type != "cpu" */
+		prop = fdt_get_property(fdt, cpus_subnode_offset, "device_type", NULL);
+		if (!prop || strcmp(prop->data, "cpu")) {
+			prev_node_offset = cpus_subnode_offset;
+			goto next_node;
+		}
+
+		ret = fdt_del_node(fdt, cpus_subnode_offset);
+		if (ret < 0) {
+			pr_err("Failed to delete a cpus sub-node: %s\n", fdt_strerror(ret));
+			return ret;
+		}
+next_node:
+		if (prev_node_offset == cpus_offset)
+			cpus_subnode_offset = fdt_first_subnode(fdt, cpus_offset);
+		else
+			cpus_subnode_offset = fdt_next_subnode(fdt, prev_node_offset);
+	}
+
+	cpus_node = of_find_node_by_path("/cpus");
+	/* Fail here to avoid kexec/kdump kernel boot hung */
+	if (!cpus_node) {
+		pr_err("No /cpus node found\n");
+		return -EINVAL;
+	}
+
+	/* Add all /cpus sub-nodes of device_type == "cpu" to FDT */
+	for_each_child_of_node(cpus_node, dn) {
+		/* Ignore device nodes that do not have a device_type property
+		 * or device_type != "cpu".
+		 */
+		device_type = of_get_property(dn, "device_type", NULL);
+		if (!device_type || strcmp(device_type, "cpu"))
+			continue;
+
+		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(cpus_node);
+	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
new file mode 100644
index 000000000..775895f31
--- /dev/null
+++ b/arch/powerpc/kexec/crash.c
@@ -0,0 +1,657 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Architecture specific (PPC64) functions for kexec based crash dumps.
+ *
+ * Copyright (C) 2005, IBM Corp.
+ *
+ * Created by: Haren Myneni
+ */
+
+#include <linux/kernel.h>
+#include <linux/smp.h>
+#include <linux/reboot.h>
+#include <linux/kexec.h>
+#include <linux/export.h>
+#include <linux/crash_dump.h>
+#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>
+#include <asm/kexec.h>
+#include <asm/smp.h>
+#include <asm/setjmp.h>
+#include <asm/debug.h>
+#include <asm/interrupt.h>
+#include <asm/kexec_ranges.h>
+#include <asm/crashdump-ppc64.h>
+
+/*
+ * The primary CPU waits a while for all secondary CPUs to enter. This is to
+ * avoid sending an IPI if the secondary CPUs are entering
+ * crash_kexec_secondary on their own (eg via a system reset).
+ *
+ * The secondary timeout has to be longer than the primary. Both timeouts are
+ * in milliseconds.
+ */
+#define PRIMARY_TIMEOUT		500
+#define SECONDARY_TIMEOUT	1000
+
+#define IPI_TIMEOUT		10000
+#define REAL_MODE_TIMEOUT	10000
+
+static int time_to_dump;
+
+/*
+ * In case of system reset, secondary CPUs enter crash_kexec_secondary with out
+ * having to send an IPI explicitly. So, indicate if the crash is via
+ * system reset to avoid sending another IPI.
+ */
+static int is_via_system_reset;
+
+/*
+ * crash_wake_offline should be set to 1 by platforms that intend to wake
+ * up offline cpus prior to jumping to a kdump kernel. Currently powernv
+ * sets it to 1, since we want to avoid things from happening when an
+ * offline CPU wakes up due to something like an HMI (malfunction error),
+ * which propagates to all threads.
+ */
+int crash_wake_offline;
+
+#define CRASH_HANDLER_MAX 3
+/* List of shutdown handles */
+static crash_shutdown_t crash_shutdown_handles[CRASH_HANDLER_MAX];
+static DEFINE_SPINLOCK(crash_handlers_lock);
+
+static unsigned long crash_shutdown_buf[JMP_BUF_LEN];
+static int crash_shutdown_cpu = -1;
+
+static int handle_fault(struct pt_regs *regs)
+{
+	if (crash_shutdown_cpu == smp_processor_id())
+		longjmp(crash_shutdown_buf, 1);
+	return 0;
+}
+
+#ifdef CONFIG_SMP
+
+static atomic_t cpus_in_crash;
+void crash_ipi_callback(struct pt_regs *regs)
+{
+	static cpumask_t cpus_state_saved = CPU_MASK_NONE;
+
+	int cpu = smp_processor_id();
+
+	hard_irq_disable();
+	if (!cpumask_test_cpu(cpu, &cpus_state_saved)) {
+		crash_save_cpu(regs, cpu);
+		cpumask_set_cpu(cpu, &cpus_state_saved);
+	}
+
+	atomic_inc(&cpus_in_crash);
+	smp_mb__after_atomic();
+
+	/*
+	 * Starting the kdump boot.
+	 * This barrier is needed to make sure that all CPUs are stopped.
+	 */
+	while (!time_to_dump)
+		cpu_relax();
+
+	if (ppc_md.kexec_cpu_down)
+		ppc_md.kexec_cpu_down(1, 1);
+
+#ifdef CONFIG_PPC64
+	kexec_smp_wait();
+#else
+	for (;;);	/* FIXME */
+#endif
+
+	/* NOTREACHED */
+}
+
+static void crash_kexec_prepare_cpus(void)
+{
+	unsigned int msecs;
+	volatile unsigned int ncpus = num_online_cpus() - 1;/* Excluding the panic cpu */
+	volatile int tries = 0;
+	int (*old_handler)(struct pt_regs *regs);
+
+	printk(KERN_EMERG "Sending IPI to other CPUs\n");
+
+	if (crash_wake_offline)
+		ncpus = num_present_cpus() - 1;
+
+	/*
+	 * If we came in via system reset, secondaries enter via crash_kexec_secondary().
+	 * So, wait a while for the secondary CPUs to enter for that case.
+	 * Else, send IPI to all other CPUs.
+	 */
+	if (is_via_system_reset)
+		mdelay(PRIMARY_TIMEOUT);
+	else
+		crash_send_ipi(crash_ipi_callback);
+	smp_wmb();
+
+again:
+	/*
+	 * FIXME: Until we will have the way to stop other CPUs reliably,
+	 * the crash CPU will send an IPI and wait for other CPUs to
+	 * respond.
+	 */
+	msecs = IPI_TIMEOUT;
+	while ((atomic_read(&cpus_in_crash) < ncpus) && (--msecs > 0))
+		mdelay(1);
+
+	/* Would it be better to replace the trap vector here? */
+
+	if (atomic_read(&cpus_in_crash) >= ncpus) {
+		printk(KERN_EMERG "IPI complete\n");
+		return;
+	}
+
+	printk(KERN_EMERG "ERROR: %d cpu(s) not responding\n",
+		ncpus - atomic_read(&cpus_in_crash));
+
+	/*
+	 * If we have a panic timeout set then we can't wait indefinitely
+	 * for someone to activate system reset. We also give up on the
+	 * second time through if system reset fail to work.
+	 */
+	if ((panic_timeout > 0) || (tries > 0))
+		return;
+
+	/*
+	 * A system reset will cause all CPUs to take an 0x100 exception.
+	 * The primary CPU returns here via setjmp, and the secondary
+	 * CPUs reexecute the crash_kexec_secondary path.
+	 */
+	old_handler = __debugger;
+	__debugger = handle_fault;
+	crash_shutdown_cpu = smp_processor_id();
+
+	if (setjmp(crash_shutdown_buf) == 0) {
+		printk(KERN_EMERG "Activate system reset (dumprestart) "
+				  "to stop other cpu(s)\n");
+
+		/*
+		 * A system reset will force all CPUs to execute the
+		 * crash code again. We need to reset cpus_in_crash so we
+		 * wait for everyone to do this.
+		 */
+		atomic_set(&cpus_in_crash, 0);
+		smp_mb();
+
+		while (atomic_read(&cpus_in_crash) < ncpus)
+			cpu_relax();
+	}
+
+	crash_shutdown_cpu = -1;
+	__debugger = old_handler;
+
+	tries++;
+	goto again;
+}
+
+/*
+ * This function will be called by secondary cpus.
+ */
+void crash_kexec_secondary(struct pt_regs *regs)
+{
+	unsigned long flags;
+	int msecs = SECONDARY_TIMEOUT;
+
+	local_irq_save(flags);
+
+	/* Wait for the primary crash CPU to signal its progress */
+	while (crashing_cpu < 0) {
+		if (--msecs < 0) {
+			/* No response, kdump image may not have been loaded */
+			local_irq_restore(flags);
+			return;
+		}
+
+		mdelay(1);
+	}
+
+	crash_ipi_callback(regs);
+}
+
+#else	/* ! CONFIG_SMP */
+
+static void crash_kexec_prepare_cpus(void)
+{
+	/*
+	 * move the secondaries to us so that we can copy
+	 * the new kernel 0-0x100 safely
+	 *
+	 * do this if kexec in setup.c ?
+	 */
+#ifdef CONFIG_PPC64
+	smp_release_cpus();
+#else
+	/* FIXME */
+#endif
+}
+
+void crash_kexec_secondary(struct pt_regs *regs)
+{
+}
+#endif	/* CONFIG_SMP */
+
+/* wait for all the CPUs to hit real mode but timeout if they don't come in */
+#if defined(CONFIG_SMP) && defined(CONFIG_PPC64)
+noinstr static void __maybe_unused crash_kexec_wait_realmode(int cpu)
+{
+	unsigned int msecs;
+	int i;
+
+	msecs = REAL_MODE_TIMEOUT;
+	for (i=0; i < nr_cpu_ids && msecs > 0; i++) {
+		if (i == cpu)
+			continue;
+
+		while (paca_ptrs[i]->kexec_state < KEXEC_STATE_REAL_MODE) {
+			barrier();
+			if (!cpu_possible(i) || !cpu_online(i) || (msecs <= 0))
+				break;
+			msecs--;
+			mdelay(1);
+		}
+	}
+	mb();
+}
+#else
+static inline void crash_kexec_wait_realmode(int cpu) {}
+#endif	/* CONFIG_SMP && CONFIG_PPC64 */
+
+void crash_kexec_prepare(void)
+{
+	/* Avoid hardlocking with irresponsive CPU holding logbuf_lock */
+	printk_deferred_enter();
+
+	/*
+	 * This function is only called after the system
+	 * has panicked or is otherwise in a critical state.
+	 * The minimum amount of code to allow a kexec'd kernel
+	 * to run successfully needs to happen here.
+	 *
+	 * In practice this means stopping other cpus in
+	 * an SMP system.
+	 * The kernel is broken so disable interrupts.
+	 */
+	hard_irq_disable();
+
+	/*
+	 * Make a note of crashing cpu. Will be used in machine_kexec
+	 * such that another IPI will not be sent.
+	 */
+	crashing_cpu = smp_processor_id();
+
+	crash_kexec_prepare_cpus();
+}
+
+/*
+ * Register a function to be called on shutdown.  Only use this if you
+ * can't reset your device in the second kernel.
+ */
+int crash_shutdown_register(crash_shutdown_t handler)
+{
+	unsigned int i, rc;
+
+	spin_lock(&crash_handlers_lock);
+	for (i = 0 ; i < CRASH_HANDLER_MAX; i++)
+		if (!crash_shutdown_handles[i]) {
+			/* Insert handle at first empty entry */
+			crash_shutdown_handles[i] = handler;
+			rc = 0;
+			break;
+		}
+
+	if (i == CRASH_HANDLER_MAX) {
+		printk(KERN_ERR "Crash shutdown handles full, "
+		       "not registered.\n");
+		rc = 1;
+	}
+
+	spin_unlock(&crash_handlers_lock);
+	return rc;
+}
+EXPORT_SYMBOL(crash_shutdown_register);
+
+int crash_shutdown_unregister(crash_shutdown_t handler)
+{
+	unsigned int i, rc;
+
+	spin_lock(&crash_handlers_lock);
+	for (i = 0 ; i < CRASH_HANDLER_MAX; i++)
+		if (crash_shutdown_handles[i] == handler)
+			break;
+
+	if (i == CRASH_HANDLER_MAX) {
+		printk(KERN_ERR "Crash shutdown handle not found\n");
+		rc = 1;
+	} else {
+		/* Shift handles down */
+		for (; i < (CRASH_HANDLER_MAX - 1); i++)
+			crash_shutdown_handles[i] =
+				crash_shutdown_handles[i+1];
+		/*
+		 * Reset last entry to NULL now that it has been shifted down,
+		 * this will allow new handles to be added here.
+		 */
+		crash_shutdown_handles[i] = NULL;
+		rc = 0;
+	}
+
+	spin_unlock(&crash_handlers_lock);
+	return rc;
+}
+EXPORT_SYMBOL(crash_shutdown_unregister);
+
+void default_machine_crash_shutdown(struct pt_regs *regs)
+{
+	volatile unsigned int i;
+	int (*old_handler)(struct pt_regs *regs);
+
+	if (TRAP(regs) == INTERRUPT_SYSTEM_RESET)
+		is_via_system_reset = 1;
+
+	if (IS_ENABLED(CONFIG_SMP))
+		crash_smp_send_stop();
+	else
+		crash_kexec_prepare();
+
+	crash_save_cpu(regs, crashing_cpu);
+
+	time_to_dump = 1;
+
+	crash_kexec_wait_realmode(crashing_cpu);
+
+	machine_kexec_mask_interrupts();
+
+	/*
+	 * Call registered shutdown routines safely.  Swap out
+	 * __debugger_fault_handler, and replace on exit.
+	 */
+	old_handler = __debugger_fault_handler;
+	__debugger_fault_handler = handle_fault;
+	crash_shutdown_cpu = smp_processor_id();
+	for (i = 0; i < CRASH_HANDLER_MAX && crash_shutdown_handles[i]; i++) {
+		if (setjmp(crash_shutdown_buf) == 0) {
+			/*
+			 * Insert syncs and delay to ensure
+			 * instructions in the dangerous region don't
+			 * leak away from this protected region.
+			 */
+			asm volatile("sync; isync");
+			/* dangerous region */
+			crash_shutdown_handles[i]();
+			asm volatile("sync; isync");
+		}
+	}
+	crash_shutdown_cpu = -1;
+	__debugger_fault_handler = old_handler;
+
+	if (ppc_md.kexec_cpu_down)
+		ppc_md.kexec_cpu_down(1, 0);
+}
+
+#ifdef CONFIG_CRASH_DUMP
+/**
+ * sync_backup_region_phdr - synchronize backup region offset between
+ *			    kexec image and ELF core header.
+ * @image: Kexec image.
+ * @ehdr: ELF core header.
+ * @phdr_to_kimage: If true, read the offset from the ELF program header
+ *		    and update the kimage backup region. If false, update
+ *		    the ELF program header offset from the kimage backup
+ *		    region.
+ *
+ * Note: During kexec_load, this is called with phdr_to_kimage = true. For
+ * kexec_file_load and ELF core header recreation during memory hotplug
+ * events, it is called with phdr_to_kimage = false.
+ *
+ * Returns nothing.
+ */
+void sync_backup_region_phdr(struct kimage *image, Elf64_Ehdr *ehdr, bool phdr_to_kimage)
+{
+	Elf64_Phdr *phdr;
+	unsigned int i;
+
+	phdr = (Elf64_Phdr *)(ehdr + 1);
+	for (i = 0; i < ehdr->e_phnum; i++, phdr++) {
+		if (phdr->p_paddr == BACKUP_SRC_START) {
+			if (phdr_to_kimage)
+				image->arch.backup_start = phdr->p_offset;
+			else
+				phdr->p_offset = image->arch.backup_start;
+
+			kexec_dprintk("Backup region offset updated to 0x%lx\n",
+				      image->arch.backup_start);
+			return;
+		}
+	}
+}
+#endif /* CONFIG_CRASH_DUMP */
+
+#ifdef CONFIG_CRASH_HOTPLUG
+
+int machine_kexec_post_load(struct kimage *image)
+{
+	int i;
+	unsigned long mem;
+	unsigned char *ptr;
+
+	if (image->type != KEXEC_TYPE_CRASH)
+		return 0;
+
+	if (image->file_mode)
+		return 0;
+
+	for (i = 0; i < image->nr_segments; i++) {
+		mem = image->segment[i].mem;
+		ptr = (char *)__va(mem);
+
+		if (ptr && memcmp(ptr, ELFMAG, SELFMAG) == 0)
+			sync_backup_region_phdr(image, (Elf64_Ehdr *) ptr, true);
+	}
+	return 0;
+}
+
+#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, end;
+
+	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");
+		goto out;
+	}
+
+	/*
+	 * 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;
+		end = base_addr + size - 1;
+		ret = arch_crash_exclude_mem_range(&cmem, base_addr, end);
+		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;
+	}
+
+	sync_backup_region_phdr(image, (Elf64_Ehdr *) elfbuf, false);
+
+	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
new file mode 100644
index 000000000..d9a466cd6
--- /dev/null
+++ b/arch/powerpc/kexec/elf_64.c
@@ -0,0 +1,170 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Load ELF vmlinux file for the kexec_file_load syscall.
+ *
+ * Copyright (C) 2004  Adam Litke (agl@us.ibm.com)
+ * Copyright (C) 2004  IBM Corp.
+ * Copyright (C) 2005  R Sharada (sharada@in.ibm.com)
+ * Copyright (C) 2006  Mohan Kumar M (mohan@in.ibm.com)
+ * Copyright (C) 2016  IBM Corporation
+ *
+ * Based on kexec-tools' kexec-elf-exec.c and kexec-elf-ppc64.c.
+ * Heavily modified for the kernel by
+ * Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>.
+ */
+
+#define pr_fmt(fmt)	"kexec_elf: " fmt
+
+#include <linux/elf.h>
+#include <linux/kexec.h>
+#include <linux/libfdt.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_fdt.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <asm/kexec_ranges.h>
+
+static void *elf64_load(struct kimage *image, char *kernel_buf,
+			unsigned long kernel_len, char *initrd,
+			unsigned long initrd_len, char *cmdline,
+			unsigned long cmdline_len)
+{
+	int ret;
+	unsigned long kernel_load_addr;
+	unsigned long initrd_load_addr = 0, fdt_load_addr;
+	void *fdt;
+	const void *slave_code;
+	struct elfhdr ehdr;
+	char *modified_cmdline = NULL;
+	struct crash_mem *rmem = NULL;
+	struct kexec_elf_info elf_info;
+	struct kexec_buf kbuf = { .image = image, .buf_min = 0,
+				  .buf_max = ppc64_rma_size };
+	struct kexec_buf pbuf = { .image = image, .buf_min = 0,
+				  .buf_max = ppc64_rma_size, .top_down = true,
+				  .mem = KEXEC_BUF_MEM_UNKNOWN };
+
+	ret = kexec_build_elf_info(kernel_buf, kernel_len, &ehdr, &elf_info);
+	if (ret)
+		return ERR_PTR(ret);
+
+	if (IS_ENABLED(CONFIG_CRASH_DUMP) && image->type == KEXEC_TYPE_CRASH) {
+		/* min & max buffer values for kdump case */
+		kbuf.buf_min = pbuf.buf_min = crashk_res.start;
+		kbuf.buf_max = pbuf.buf_max =
+				((crashk_res.end < ppc64_rma_size) ?
+				 crashk_res.end : (ppc64_rma_size - 1));
+	}
+
+	ret = kexec_elf_load(image, &ehdr, &elf_info, &kbuf, &kernel_load_addr);
+	if (ret)
+		goto out;
+
+	kexec_dprintk("Loaded the kernel at 0x%lx\n", kernel_load_addr);
+
+	ret = kexec_load_purgatory(image, &pbuf);
+	if (ret) {
+		pr_err("Loading purgatory failed.\n");
+		goto out;
+	}
+
+	kexec_dprintk("Loaded purgatory at 0x%lx\n", pbuf.mem);
+
+	/* Load additional segments needed for panic kernel */
+	if (IS_ENABLED(CONFIG_CRASH_DUMP) && image->type == KEXEC_TYPE_CRASH) {
+		ret = load_crashdump_segments_ppc64(image, &kbuf);
+		if (ret) {
+			pr_err("Failed to load kdump kernel segments\n");
+			goto out;
+		}
+
+		ret = crash_load_dm_crypt_keys(image);
+		if (ret)
+			goto out;
+
+		/* Setup cmdline for kdump kernel case */
+		modified_cmdline = setup_kdump_cmdline(image, cmdline,
+						       cmdline_len);
+		if (!modified_cmdline) {
+			pr_err("Setting up cmdline for kdump kernel failed\n");
+			ret = -EINVAL;
+			goto out;
+		}
+		cmdline = modified_cmdline;
+	}
+
+	kexec_dprintk("Command line: %s", cmdline ? cmdline : "");
+
+	if (initrd != NULL) {
+		kbuf.buffer = initrd;
+		kbuf.bufsz = kbuf.memsz = initrd_len;
+		kbuf.buf_align = PAGE_SIZE;
+		kbuf.top_down = false;
+		kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
+		ret = kexec_add_buffer(&kbuf);
+		if (ret)
+			goto out;
+		initrd_load_addr = kbuf.mem;
+
+		kexec_dprintk("Loaded initrd at 0x%lx\n", initrd_load_addr);
+	}
+
+	ret = get_reserved_memory_ranges(&rmem);
+	if (ret)
+		goto out;
+
+	fdt = of_kexec_alloc_and_setup_fdt(image, initrd_load_addr,
+					   initrd_len, cmdline,
+					   kexec_extra_fdt_size_ppc64(image, rmem));
+	if (!fdt) {
+		pr_err("Error setting up the new device tree.\n");
+		ret = -EINVAL;
+		goto out;
+	}
+
+	ret = setup_new_fdt_ppc64(image, fdt, rmem);
+	if (ret)
+		goto out_free_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);
+	kbuf.buf_align = PAGE_SIZE;
+	kbuf.top_down = true;
+	kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
+	ret = kexec_add_buffer(&kbuf);
+	if (ret)
+		goto out_free_fdt;
+
+	/* FDT will be freed in arch_kimage_file_post_load_cleanup */
+	image->arch.fdt = fdt;
+
+	fdt_load_addr = kbuf.mem;
+
+	kexec_dprintk("Loaded device tree at 0x%lx\n", fdt_load_addr);
+
+	slave_code = elf_info.buffer + elf_info.proghdrs[0].p_offset;
+	ret = setup_purgatory_ppc64(image, slave_code, fdt, kernel_load_addr,
+				    fdt_load_addr);
+	if (ret)
+		pr_err("Error setting up the purgatory.\n");
+
+	goto out;
+
+out_free_fdt:
+	kvfree(fdt);
+out:
+	kfree(rmem);
+	kfree(modified_cmdline);
+	kexec_free_elf_info(&elf_info);
+
+	return ret ? ERR_PTR(ret) : NULL;
+}
+
+const struct kexec_file_ops kexec_elf64_ops = {
+	.probe = kexec_elf_probe,
+	.load = elf64_load,
+};
diff --git a/arch/powerpc/kexec/file_load.c b/arch/powerpc/kexec/file_load.c
new file mode 100644
index 000000000..597998235
--- /dev/null
+++ b/arch/powerpc/kexec/file_load.c
@@ -0,0 +1,103 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * powerpc code to implement the kexec_file_load syscall
+ *
+ * Copyright (C) 2004  Adam Litke (agl@us.ibm.com)
+ * Copyright (C) 2004  IBM Corp.
+ * Copyright (C) 2004,2005  Milton D Miller II, IBM Corporation
+ * Copyright (C) 2005  R Sharada (sharada@in.ibm.com)
+ * Copyright (C) 2006  Mohan Kumar M (mohan@in.ibm.com)
+ * Copyright (C) 2016  IBM Corporation
+ *
+ * Based on kexec-tools' kexec-elf-ppc64.c, fs2dt.c.
+ * Heavily modified for the kernel by
+ * Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>.
+ */
+
+#include <linux/slab.h>
+#include <linux/kexec.h>
+#include <linux/of_fdt.h>
+#include <linux/libfdt.h>
+#include <asm/setup.h>
+
+#define SLAVE_CODE_SIZE		256	/* First 0x100 bytes */
+
+/**
+ * setup_kdump_cmdline - Prepend "elfcorehdr=<addr> " to command line
+ *                       of kdump kernel for exporting the core.
+ * @image:               Kexec image
+ * @cmdline:             Command line parameters to update.
+ * @cmdline_len:         Length of the cmdline parameters.
+ *
+ * kdump segment must be setup before calling this function.
+ *
+ * Returns new cmdline buffer for kdump kernel on success, NULL otherwise.
+ */
+char *setup_kdump_cmdline(struct kimage *image, char *cmdline,
+			  unsigned long cmdline_len)
+{
+	char *cmdline_ptr;
+
+	cmdline_ptr = kmalloc(COMMAND_LINE_SIZE, GFP_KERNEL);
+	if (!cmdline_ptr)
+		return NULL;
+
+	if (snprintf(cmdline_ptr, COMMAND_LINE_SIZE, "elfcorehdr=0x%lx %s",
+		     image->elf_load_addr, cmdline_len ? cmdline : "") >= COMMAND_LINE_SIZE) {
+		pr_err("Prepending elfcorehdr=<addr> exceeds cmdline size\n");
+		kfree(cmdline_ptr);
+		return NULL;
+	}
+
+	return cmdline_ptr;
+}
+
+/**
+ * setup_purgatory - initialize the purgatory's global variables
+ * @image:		kexec image.
+ * @slave_code:		Slave code for the purgatory.
+ * @fdt:		Flattened device tree for the next kernel.
+ * @kernel_load_addr:	Address where the kernel is loaded.
+ * @fdt_load_addr:	Address where the flattened device tree is loaded.
+ *
+ * Return: 0 on success, or negative errno on error.
+ */
+int setup_purgatory(struct kimage *image, const void *slave_code,
+		    const void *fdt, unsigned long kernel_load_addr,
+		    unsigned long fdt_load_addr)
+{
+	unsigned int *slave_code_buf, master_entry;
+	int ret;
+
+	slave_code_buf = kmalloc(SLAVE_CODE_SIZE, GFP_KERNEL);
+	if (!slave_code_buf)
+		return -ENOMEM;
+
+	/* Get the slave code from the new kernel and put it in purgatory. */
+	ret = kexec_purgatory_get_set_symbol(image, "purgatory_start",
+					     slave_code_buf, SLAVE_CODE_SIZE,
+					     true);
+	if (ret) {
+		kfree(slave_code_buf);
+		return ret;
+	}
+
+	master_entry = slave_code_buf[0];
+	memcpy(slave_code_buf, slave_code, SLAVE_CODE_SIZE);
+	slave_code_buf[0] = master_entry;
+	ret = kexec_purgatory_get_set_symbol(image, "purgatory_start",
+					     slave_code_buf, SLAVE_CODE_SIZE,
+					     false);
+	kfree(slave_code_buf);
+
+	ret = kexec_purgatory_get_set_symbol(image, "kernel", &kernel_load_addr,
+					     sizeof(kernel_load_addr), false);
+	if (ret)
+		return ret;
+	ret = kexec_purgatory_get_set_symbol(image, "dt_offset", &fdt_load_addr,
+					     sizeof(fdt_load_addr), false);
+	if (ret)
+		return ret;
+
+	return 0;
+}
diff --git a/arch/powerpc/kexec/file_load_64.c b/arch/powerpc/kexec/file_load_64.c
new file mode 100644
index 000000000..bd80c5fb1
--- /dev/null
+++ b/arch/powerpc/kexec/file_load_64.c
@@ -0,0 +1,852 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * ppc64 code to implement the kexec_file_load syscall
+ *
+ * Copyright (C) 2004  Adam Litke (agl@us.ibm.com)
+ * Copyright (C) 2004  IBM Corp.
+ * Copyright (C) 2004,2005  Milton D Miller II, IBM Corporation
+ * Copyright (C) 2005  R Sharada (sharada@in.ibm.com)
+ * Copyright (C) 2006  Mohan Kumar M (mohan@in.ibm.com)
+ * Copyright (C) 2020  IBM Corporation
+ *
+ * Based on kexec-tools' kexec-ppc64.c, kexec-elf-rel-ppc64.c, fs2dt.c.
+ * Heavily modified for the kernel by
+ * Hari Bathini, IBM Corporation.
+ */
+
+#include <linux/kexec.h>
+#include <linux/of_fdt.h>
+#include <linux/libfdt.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/memblock.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <asm/setup.h>
+#include <asm/drmem.h>
+#include <asm/firmware.h>
+#include <asm/kexec_ranges.h>
+#include <asm/crashdump-ppc64.h>
+#include <asm/mmzone.h>
+#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 */
+	u32 size;		/* size allocated for the data buffer */
+	u32 max_entries;	/* maximum no. of entries */
+	u32 idx;		/* index of current entry */
+
+	/* usable memory ranges to look up */
+	unsigned int nr_ranges;
+	const struct range *ranges;
+};
+
+const struct kexec_file_ops * const kexec_file_loaders[] = {
+	&kexec_elf64_ops,
+	NULL
+};
+
+int arch_check_excluded_range(struct kimage *image, unsigned long start,
+			      unsigned long end)
+{
+	struct crash_mem *emem;
+	int i;
+
+	emem = image->arch.exclude_ranges;
+	for (i = 0; i < emem->nr_ranges; i++)
+		if (start <= emem->ranges[i].end && end >= emem->ranges[i].start)
+			return 1;
+
+	return 0;
+}
+
+#ifdef CONFIG_CRASH_DUMP
+/**
+ * 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.
+ *
+ * Frees up the old buffer if memory reallocation fails.
+ *
+ * Returns buffer on success, NULL on error.
+ */
+static __be64 *check_realloc_usable_mem(struct umem_info *um_info, int cnt)
+{
+	u32 new_size;
+	__be64 *tbuf;
+
+	if ((um_info->idx + cnt) <= um_info->max_entries)
+		return um_info->buf;
+
+	new_size = um_info->size + MEM_RANGE_CHUNK_SZ;
+	tbuf = krealloc(um_info->buf, new_size, GFP_KERNEL);
+	if (tbuf) {
+		um_info->buf = tbuf;
+		um_info->size = new_size;
+		um_info->max_entries = (um_info->size / sizeof(u64));
+	}
+
+	return tbuf;
+}
+
+/**
+ * add_usable_mem - Add the usable memory ranges within the given memory range
+ *                  to the buffer
+ * @um_info:        Usable memory buffer and ranges info.
+ * @base:           Base address of memory range to look for.
+ * @end:            End address of memory range to look for.
+ *
+ * Returns 0 on success, negative errno on error.
+ */
+static int add_usable_mem(struct umem_info *um_info, u64 base, u64 end)
+{
+	u64 loc_base, loc_end;
+	bool add;
+	int i;
+
+	for (i = 0; i < um_info->nr_ranges; i++) {
+		add = false;
+		loc_base = um_info->ranges[i].start;
+		loc_end = um_info->ranges[i].end;
+		if (loc_base >= base && loc_end <= end)
+			add = true;
+		else if (base <= loc_end && end >= loc_base) {
+			if (loc_base < base)
+				loc_base = base;
+			if (loc_end > end)
+				loc_end = end;
+			add = true;
+		}
+
+		if (add) {
+			if (!check_realloc_usable_mem(um_info, 2))
+				return -ENOMEM;
+
+			um_info->buf[um_info->idx++] = cpu_to_be64(loc_base);
+			um_info->buf[um_info->idx++] =
+					cpu_to_be64(loc_end - loc_base + 1);
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * kdump_setup_usable_lmb - This is a callback function that gets called by
+ *                          walk_drmem_lmbs for every LMB to set its
+ *                          usable memory ranges.
+ * @lmb:                    LMB info.
+ * @usm:                    linux,drconf-usable-memory property value.
+ * @data:                   Pointer to usable memory buffer and ranges info.
+ *
+ * Returns 0 on success, negative errno on error.
+ */
+static int kdump_setup_usable_lmb(struct drmem_lmb *lmb, const __be32 **usm,
+				  void *data)
+{
+	struct umem_info *um_info;
+	int tmp_idx, ret;
+	u64 base, end;
+
+	/*
+	 * kdump load isn't supported on kernels already booted with
+	 * linux,drconf-usable-memory property.
+	 */
+	if (*usm) {
+		pr_err("linux,drconf-usable-memory property already exists!");
+		return -EINVAL;
+	}
+
+	um_info = data;
+	tmp_idx = um_info->idx;
+	if (!check_realloc_usable_mem(um_info, 1))
+		return -ENOMEM;
+
+	um_info->idx++;
+	base = lmb->base_addr;
+	end = base + drmem_lmb_size() - 1;
+	ret = add_usable_mem(um_info, base, end);
+	if (!ret) {
+		/*
+		 * Update the no. of ranges added. Two entries (base & size)
+		 * for every range added.
+		 */
+		um_info->buf[tmp_idx] =
+				cpu_to_be64((um_info->idx - tmp_idx - 1) / 2);
+	}
+
+	return ret;
+}
+
+#define NODE_PATH_LEN		256
+/**
+ * add_usable_mem_property - Add usable memory property for the given
+ *                           memory node.
+ * @fdt:                     Flattened device tree for the kdump kernel.
+ * @dn:                      Memory node.
+ * @um_info:                 Usable memory buffer and ranges info.
+ *
+ * Returns 0 on success, negative errno on error.
+ */
+static int add_usable_mem_property(void *fdt, struct device_node *dn,
+				   struct umem_info *um_info)
+{
+	int node;
+	char path[NODE_PATH_LEN];
+	int i, ret;
+	u64 base, size;
+
+	of_node_get(dn);
+
+	if (snprintf(path, NODE_PATH_LEN, "%pOF", dn) > (NODE_PATH_LEN - 1)) {
+		pr_err("Buffer (%d) too small for memory node: %pOF\n",
+		       NODE_PATH_LEN, dn);
+		return -EOVERFLOW;
+	}
+	kexec_dprintk("Memory node path: %s\n", path);
+
+	/* Now that we know the path, find its offset in kdump kernel's fdt */
+	node = fdt_path_offset(fdt, path);
+	if (node < 0) {
+		pr_err("Malformed device tree: error reading %s\n", path);
+		ret = -EINVAL;
+		goto out;
+	}
+
+	um_info->idx  = 0;
+	if (!check_realloc_usable_mem(um_info, 2)) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	/*
+	 * "reg" property represents sequence of (addr,size) tuples
+	 * each representing a memory range.
+	 */
+	for (i = 0; ; i++) {
+		ret = of_property_read_reg(dn, i, &base, &size);
+		if (ret)
+			break;
+
+		ret = add_usable_mem(um_info, base, base + size - 1);
+		if (ret)
+			goto out;
+	}
+
+	// No reg or empty reg? Skip this node.
+	if (i == 0)
+		goto out;
+
+	/*
+	 * No kdump kernel usable memory found in this memory node.
+	 * Write (0,0) tuple in linux,usable-memory property for
+	 * this region to be ignored.
+	 */
+	if (um_info->idx == 0) {
+		um_info->buf[0] = 0;
+		um_info->buf[1] = 0;
+		um_info->idx = 2;
+	}
+
+	ret = fdt_setprop(fdt, node, "linux,usable-memory", um_info->buf,
+			  (um_info->idx * sizeof(u64)));
+
+out:
+	of_node_put(dn);
+	return ret;
+}
+
+
+/**
+ * update_usable_mem_fdt - Updates kdump kernel's fdt with linux,usable-memory
+ *                         and linux,drconf-usable-memory DT properties as
+ *                         appropriate to restrict its memory usage.
+ * @fdt:                   Flattened device tree for the kdump kernel.
+ * @usable_mem:            Usable memory ranges for kdump kernel.
+ *
+ * Returns 0 on success, negative errno on error.
+ */
+static int update_usable_mem_fdt(void *fdt, struct crash_mem *usable_mem)
+{
+	struct umem_info um_info;
+	struct device_node *dn;
+	int node, ret = 0;
+
+	if (!usable_mem) {
+		pr_err("Usable memory ranges for kdump kernel not found\n");
+		return -ENOENT;
+	}
+
+	node = fdt_path_offset(fdt, "/ibm,dynamic-reconfiguration-memory");
+	if (node == -FDT_ERR_NOTFOUND)
+		kexec_dprintk("No dynamic reconfiguration memory found\n");
+	else if (node < 0) {
+		pr_err("Malformed device tree: error reading /ibm,dynamic-reconfiguration-memory.\n");
+		return -EINVAL;
+	}
+
+	um_info.buf  = NULL;
+	um_info.size = 0;
+	um_info.max_entries = 0;
+	um_info.idx  = 0;
+	/* Memory ranges to look up */
+	um_info.ranges = &(usable_mem->ranges[0]);
+	um_info.nr_ranges = usable_mem->nr_ranges;
+
+	dn = of_find_node_by_path("/ibm,dynamic-reconfiguration-memory");
+	if (dn) {
+		ret = walk_drmem_lmbs(dn, &um_info, kdump_setup_usable_lmb);
+		of_node_put(dn);
+
+		if (ret) {
+			pr_err("Could not setup linux,drconf-usable-memory property for kdump\n");
+			goto out;
+		}
+
+		ret = fdt_setprop(fdt, node, "linux,drconf-usable-memory",
+				  um_info.buf, (um_info.idx * sizeof(u64)));
+		if (ret) {
+			pr_err("Failed to update fdt with linux,drconf-usable-memory property: %s",
+			       fdt_strerror(ret));
+			goto out;
+		}
+	}
+
+	/*
+	 * Walk through each memory node and set linux,usable-memory property
+	 * for the corresponding node in kdump kernel's fdt.
+	 */
+	for_each_node_by_type(dn, "memory") {
+		ret = add_usable_mem_property(fdt, dn, &um_info);
+		if (ret) {
+			pr_err("Failed to set linux,usable-memory property for %s node",
+			       dn->full_name);
+			of_node_put(dn);
+			goto out;
+		}
+	}
+
+out:
+	kfree(um_info.buf);
+	return ret;
+}
+
+/**
+ * load_backup_segment - Locate a memory hole to place the backup region.
+ * @image:               Kexec image.
+ * @kbuf:                Buffer contents and memory parameters.
+ *
+ * Returns 0 on success, negative errno on error.
+ */
+static int load_backup_segment(struct kimage *image, struct kexec_buf *kbuf)
+{
+	void *buf;
+	int ret;
+
+	/*
+	 * Setup a source buffer for backup segment.
+	 *
+	 * A source buffer has no meaning for backup region as data will
+	 * be copied from backup source, after crash, in the purgatory.
+	 * But as load segment code doesn't recognize such segments,
+	 * setup a dummy source buffer to keep it happy for now.
+	 */
+	buf = vzalloc(BACKUP_SRC_SIZE);
+	if (!buf)
+		return -ENOMEM;
+
+	kbuf->buffer = buf;
+	kbuf->mem = KEXEC_BUF_MEM_UNKNOWN;
+	kbuf->bufsz = kbuf->memsz = BACKUP_SRC_SIZE;
+	kbuf->top_down = false;
+
+	ret = kexec_add_buffer(kbuf);
+	if (ret) {
+		vfree(buf);
+		return ret;
+	}
+
+	image->arch.backup_buf = buf;
+	image->arch.backup_start = kbuf->mem;
+	return 0;
+}
+
+static unsigned int kdump_extra_elfcorehdr_size(struct crash_mem *cmem)
+{
+#if defined(CONFIG_CRASH_HOTPLUG) && defined(CONFIG_MEMORY_HOTPLUG)
+	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
+		return (CONFIG_CRASH_MAX_MEMORY_RANGES - cmem->nr_ranges) * sizeof(Elf64_Phdr);
+#endif
+	return 0;
+}
+
+/**
+ * load_elfcorehdr_segment - Setup crash memory ranges and initialize elfcorehdr
+ *                           segment needed to load kdump kernel.
+ * @image:                   Kexec image.
+ * @kbuf:                    Buffer contents and memory parameters.
+ *
+ * Returns 0 on success, negative errno on error.
+ */
+static int load_elfcorehdr_segment(struct kimage *image, struct kexec_buf *kbuf)
+{
+	struct crash_mem *cmem = NULL;
+	unsigned long headers_sz;
+	void *headers = NULL;
+	int ret;
+
+	ret = get_crash_memory_ranges(&cmem);
+	if (ret)
+		goto out;
+
+	/* Setup elfcorehdr segment */
+	ret = crash_prepare_elf64_headers(cmem, false, &headers, &headers_sz);
+	if (ret) {
+		pr_err("Failed to prepare elf headers for the core\n");
+		goto out;
+	}
+
+	/* Fix the offset for backup region in the ELF header */
+	sync_backup_region_phdr(image, headers, false);
+
+	kbuf->buffer = headers;
+	kbuf->mem = KEXEC_BUF_MEM_UNKNOWN;
+	kbuf->bufsz = headers_sz;
+
+	/*
+	 * Account for extra space required to accommodate additional memory
+	 * ranges in elfcorehdr due to memory hotplug events.
+	 */
+	kbuf->memsz = headers_sz + kdump_extra_elfcorehdr_size(cmem);
+	kbuf->top_down = false;
+
+	ret = kexec_add_buffer(kbuf);
+	if (ret) {
+		vfree(headers);
+		goto out;
+	}
+
+	image->elf_load_addr = kbuf->mem;
+
+	/*
+	 * If CONFIG_CRASH_HOTPLUG is enabled, the elfcorehdr kexec segment
+	 * memsz can be larger than bufsz. Always initialize elf_headers_sz
+	 * with memsz. This ensures the correct size is reserved for elfcorehdr
+	 * memory in the FDT prepared for kdump.
+	 */
+	image->elf_headers_sz = kbuf->memsz;
+	image->elf_headers = headers;
+out:
+	kfree(cmem);
+	return ret;
+}
+
+/**
+ * load_crashdump_segments_ppc64 - Initialize the additional segements needed
+ *                                 to load kdump kernel.
+ * @image:                         Kexec image.
+ * @kbuf:                          Buffer contents and memory parameters.
+ *
+ * Returns 0 on success, negative errno on error.
+ */
+int load_crashdump_segments_ppc64(struct kimage *image,
+				  struct kexec_buf *kbuf)
+{
+	int ret;
+
+	/* Load backup segment - first 64K bytes of the crashing kernel */
+	ret = load_backup_segment(image, kbuf);
+	if (ret) {
+		pr_err("Failed to load backup segment\n");
+		return ret;
+	}
+	kexec_dprintk("Loaded the backup region at 0x%lx\n", kbuf->mem);
+
+	/* Load elfcorehdr segment - to export crashing kernel's vmcore */
+	ret = load_elfcorehdr_segment(image, kbuf);
+	if (ret) {
+		pr_err("Failed to load elfcorehdr segment\n");
+		return ret;
+	}
+	kexec_dprintk("Loaded elf core header at 0x%lx, bufsz=0x%lx memsz=0x%lx\n",
+		      image->elf_load_addr, kbuf->bufsz, kbuf->memsz);
+
+	return 0;
+}
+#endif
+
+/**
+ * setup_purgatory_ppc64 - initialize PPC64 specific purgatory's global
+ *                         variables and call setup_purgatory() to initialize
+ *                         common global variable.
+ * @image:                 kexec image.
+ * @slave_code:            Slave code for the purgatory.
+ * @fdt:                   Flattened device tree for the next kernel.
+ * @kernel_load_addr:      Address where the kernel is loaded.
+ * @fdt_load_addr:         Address where the flattened device tree is loaded.
+ *
+ * Returns 0 on success, negative errno on error.
+ */
+int setup_purgatory_ppc64(struct kimage *image, const void *slave_code,
+			  const void *fdt, unsigned long kernel_load_addr,
+			  unsigned long fdt_load_addr)
+{
+	struct device_node *dn = NULL;
+	int ret;
+
+	ret = setup_purgatory(image, slave_code, fdt, kernel_load_addr,
+			      fdt_load_addr);
+	if (ret)
+		goto out;
+
+	if (image->type == KEXEC_TYPE_CRASH) {
+		u32 my_run_at_load = 1;
+
+		/*
+		 * Tell relocatable kernel to run at load address
+		 * via the word meant for that at 0x5c.
+		 */
+		ret = kexec_purgatory_get_set_symbol(image, "run_at_load",
+						     &my_run_at_load,
+						     sizeof(my_run_at_load),
+						     false);
+		if (ret)
+			goto out;
+	}
+
+	/* Tell purgatory where to look for backup region */
+	ret = kexec_purgatory_get_set_symbol(image, "backup_start",
+					     &image->arch.backup_start,
+					     sizeof(image->arch.backup_start),
+					     false);
+	if (ret)
+		goto out;
+
+	/* Setup OPAL base & entry values */
+	dn = of_find_node_by_path("/ibm,opal");
+	if (dn) {
+		u64 val;
+
+		ret = of_property_read_u64(dn, "opal-base-address", &val);
+		if (ret)
+			goto out;
+
+		ret = kexec_purgatory_get_set_symbol(image, "opal_base", &val,
+						     sizeof(val), false);
+		if (ret)
+			goto out;
+
+		ret = of_property_read_u64(dn, "opal-entry-address", &val);
+		if (ret)
+			goto out;
+		ret = kexec_purgatory_get_set_symbol(image, "opal_entry", &val,
+						     sizeof(val), false);
+	}
+out:
+	if (ret)
+		pr_err("Failed to setup purgatory symbols");
+	of_node_put(dn);
+	return ret;
+}
+
+/**
+ * cpu_node_size - Compute the size of a CPU node in the FDT.
+ *                 This should be done only once and the value is stored in
+ *                 a static variable.
+ * Returns the max size of a CPU node in the FDT.
+ */
+static unsigned int cpu_node_size(void)
+{
+	static unsigned int size;
+	struct device_node *dn;
+	struct property *pp;
+
+	/*
+	 * Don't compute it twice, we are assuming that the per CPU node size
+	 * doesn't change during the system's life.
+	 */
+	if (size)
+		return size;
+
+	dn = of_find_node_by_type(NULL, "cpu");
+	if (WARN_ON_ONCE(!dn)) {
+		// Unlikely to happen
+		return 0;
+	}
+
+	/*
+	 * We compute the sub node size for a CPU node, assuming it
+	 * will be the same for all.
+	 */
+	size += strlen(dn->name) + 5;
+	for_each_property_of_node(dn, pp) {
+		size += strlen(pp->name);
+		size += pp->length;
+	}
+
+	of_node_put(dn);
+	return size;
+}
+
+static unsigned int kdump_extra_fdt_size_ppc64(struct kimage *image, unsigned int cpu_nodes)
+{
+	unsigned int extra_size = 0;
+	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;
+
+	/*
+	 * For kdump kernel, account for linux,usable-memory and
+	 * linux,drconf-usable-memory properties. Get an approximate on the
+	 * number of usable memory entries and use for FDT size estimation.
+	 */
+	if (drmem_lmb_size()) {
+		usm_entries = ((memory_hotplug_max() / drmem_lmb_size()) +
+			       (2 * (resource_size(&crashk_res) / drmem_lmb_size())));
+		extra_size += (unsigned int)(usm_entries * sizeof(u64));
+	}
+
+#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;
+}
+
+/**
+ * kexec_extra_fdt_size_ppc64 - Return the estimated additional size needed to
+ *                              setup FDT for kexec/kdump kernel.
+ * @image:                      kexec image being loaded.
+ *
+ * Returns the estimated extra size needed for kexec/kdump kernel FDT.
+ */
+unsigned int kexec_extra_fdt_size_ppc64(struct kimage *image, struct crash_mem *rmem)
+{
+	struct device_node *dn;
+	unsigned int cpu_nodes = 0, extra_size = 0;
+
+	// Budget some space for the password blob. There's already extra space
+	// for the key name
+	if (plpks_is_available())
+		extra_size += (unsigned int)plpks_get_passwordlen();
+
+	/* Get the number of CPU nodes in the current device tree */
+	for_each_node_by_type(dn, "cpu") {
+		cpu_nodes++;
+	}
+
+	/* Consider extra space for CPU nodes added since the boot time */
+	if (cpu_nodes > boot_cpu_node_count)
+		extra_size += (cpu_nodes - boot_cpu_node_count) * cpu_node_size();
+
+	/* Consider extra space for reserved memory ranges if any */
+	if (rmem && rmem->nr_ranges > 0)
+		extra_size += sizeof(struct fdt_reserve_entry) * rmem->nr_ranges;
+
+	return extra_size + kdump_extra_fdt_size_ppc64(image, cpu_nodes);
+}
+
+static int copy_property(void *fdt, int node_offset, const struct device_node *dn,
+			 const char *propname)
+{
+	const void *prop, *fdtprop;
+	int len = 0, fdtlen = 0;
+
+	prop = of_get_property(dn, propname, &len);
+	fdtprop = fdt_getprop(fdt, node_offset, propname, &fdtlen);
+
+	if (fdtprop && !prop)
+		return fdt_delprop(fdt, node_offset, propname);
+	else if (prop)
+		return fdt_setprop(fdt, node_offset, propname, prop, len);
+	else
+		return -FDT_ERR_NOTFOUND;
+}
+
+static int update_pci_dma_nodes(void *fdt, const char *dmapropname)
+{
+	struct device_node *dn;
+	int pci_offset, root_offset, ret = 0;
+
+	if (!firmware_has_feature(FW_FEATURE_LPAR))
+		return 0;
+
+	root_offset = fdt_path_offset(fdt, "/");
+	for_each_node_with_property(dn, dmapropname) {
+		pci_offset = fdt_subnode_offset(fdt, root_offset, of_node_full_name(dn));
+		if (pci_offset < 0)
+			continue;
+
+		ret = copy_property(fdt, pci_offset, dn, "ibm,dma-window");
+		if (ret < 0) {
+			of_node_put(dn);
+			break;
+		}
+		ret = copy_property(fdt, pci_offset, dn, dmapropname);
+		if (ret < 0) {
+			of_node_put(dn);
+			break;
+		}
+	}
+
+	return ret;
+}
+
+/**
+ * setup_new_fdt_ppc64 - Update the flattend device-tree of the kernel
+ *                       being loaded.
+ * @image:               kexec image being loaded.
+ * @fdt:                 Flattened device tree for the next kernel.
+ * @rmem:                Reserved memory ranges.
+ *
+ * Returns 0 on success, negative errno on error.
+ */
+int setup_new_fdt_ppc64(const struct kimage *image, void *fdt, struct crash_mem *rmem)
+{
+	struct crash_mem *umem = NULL;
+	int i, nr_ranges, ret;
+
+#ifdef CONFIG_CRASH_DUMP
+	/*
+	 * Restrict memory usage for kdump kernel by setting up
+	 * usable memory ranges and memory reserve map.
+	 */
+	if (image->type == KEXEC_TYPE_CRASH) {
+		ret = get_usable_memory_ranges(&umem);
+		if (ret)
+			goto out;
+
+		ret = update_usable_mem_fdt(fdt, umem);
+		if (ret) {
+			pr_err("Error setting up usable-memory property for kdump kernel\n");
+			goto out;
+		}
+
+		/*
+		 * Ensure we don't touch crashed kernel's memory except the
+		 * first 64K of RAM, which will be backed up.
+		 */
+		ret = fdt_add_mem_rsv(fdt, BACKUP_SRC_END + 1,
+				      crashk_res.start - BACKUP_SRC_SIZE);
+		if (ret) {
+			pr_err("Error reserving crash memory: %s\n",
+			       fdt_strerror(ret));
+			goto out;
+		}
+
+		/* Ensure backup region is not used by kdump/capture kernel */
+		ret = fdt_add_mem_rsv(fdt, image->arch.backup_start,
+				      BACKUP_SRC_SIZE);
+		if (ret) {
+			pr_err("Error reserving memory for backup: %s\n",
+			       fdt_strerror(ret));
+			goto out;
+		}
+	}
+#endif
+
+	/* Update cpus nodes information to account hotplug CPUs. */
+	ret =  update_cpus_node(fdt);
+	if (ret < 0)
+		goto out;
+
+	ret = update_pci_dma_nodes(fdt, DIRECT64_PROPNAME);
+	if (ret < 0)
+		goto out;
+
+	ret = update_pci_dma_nodes(fdt, DMA64_PROPNAME);
+	if (ret < 0)
+		goto out;
+
+	/* Update memory reserve map */
+	nr_ranges = rmem ? rmem->nr_ranges : 0;
+	for (i = 0; i < nr_ranges; i++) {
+		u64 base, size;
+
+		base = rmem->ranges[i].start;
+		size = rmem->ranges[i].end - base + 1;
+		ret = fdt_add_mem_rsv(fdt, base, size);
+		if (ret) {
+			pr_err("Error updating memory reserve map: %s\n",
+			       fdt_strerror(ret));
+			goto out;
+		}
+	}
+
+	// If we have PLPKS active, we need to provide the password to the new kernel
+	if (plpks_is_available())
+		ret = plpks_populate_fdt(fdt);
+
+out:
+	kfree(umem);
+	return ret;
+}
+
+/**
+ * arch_kexec_kernel_image_probe - Does additional handling needed to setup
+ *                                 kexec segments.
+ * @image:                         kexec image being loaded.
+ * @buf:                           Buffer pointing to elf data.
+ * @buf_len:                       Length of the buffer.
+ *
+ * Returns 0 on success, negative errno on error.
+ */
+int arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
+				  unsigned long buf_len)
+{
+	int ret;
+
+	/* Get exclude memory ranges needed for setting up kexec segments */
+	ret = get_exclude_memory_ranges(&(image->arch.exclude_ranges));
+	if (ret) {
+		pr_err("Failed to setup exclude memory ranges for buffer lookup\n");
+		return ret;
+	}
+
+	return kexec_image_probe_default(image, buf, buf_len);
+}
+
+/**
+ * arch_kimage_file_post_load_cleanup - Frees up all the allocations done
+ *                                      while loading the image.
+ * @image:                              kexec image being loaded.
+ *
+ * Returns 0 on success, negative errno on error.
+ */
+int arch_kimage_file_post_load_cleanup(struct kimage *image)
+{
+	kfree(image->arch.exclude_ranges);
+	image->arch.exclude_ranges = NULL;
+
+	vfree(image->arch.backup_buf);
+	image->arch.backup_buf = NULL;
+
+	vfree(image->elf_headers);
+	image->elf_headers = NULL;
+	image->elf_headers_sz = 0;
+
+	kvfree(image->arch.fdt);
+	image->arch.fdt = NULL;
+
+	return kexec_image_post_load_cleanup_default(image);
+}
diff --git a/arch/powerpc/kexec/ranges.c b/arch/powerpc/kexec/ranges.c
new file mode 100644
index 000000000..539061d14
--- /dev/null
+++ b/arch/powerpc/kexec/ranges.c
@@ -0,0 +1,634 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * powerpc code to implement the kexec_file_load syscall
+ *
+ * Copyright (C) 2004  Adam Litke (agl@us.ibm.com)
+ * Copyright (C) 2004  IBM Corp.
+ * Copyright (C) 2004,2005  Milton D Miller II, IBM Corporation
+ * Copyright (C) 2005  R Sharada (sharada@in.ibm.com)
+ * Copyright (C) 2006  Mohan Kumar M (mohan@in.ibm.com)
+ * Copyright (C) 2020  IBM Corporation
+ *
+ * Based on kexec-tools' kexec-ppc64.c, fs2dt.c.
+ * Heavily modified for the kernel by
+ * Hari Bathini, IBM Corporation.
+ */
+
+#define pr_fmt(fmt) "kexec ranges: " fmt
+
+#include <linux/sort.h>
+#include <linux/kexec.h>
+#include <linux/of.h>
+#include <linux/slab.h>
+#include <linux/memblock.h>
+#include <linux/minmax.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.
+ * @size:              Allocation size of crash_mem structure.
+ *
+ * Returns the maximum no. of ranges.
+ */
+static inline unsigned int get_max_nr_ranges(size_t size)
+{
+	return ((size - sizeof(struct crash_mem)) /
+		sizeof(struct range));
+}
+
+/**
+ * get_mem_rngs_size - Get the allocated size of mem_rngs based on
+ *                     max_nr_ranges and chunk size.
+ * @mem_rngs:          Memory ranges.
+ *
+ * Returns the maximum size of @mem_rngs.
+ */
+static inline size_t get_mem_rngs_size(struct crash_mem *mem_rngs)
+{
+	size_t size;
+
+	if (!mem_rngs)
+		return 0;
+
+	size = (sizeof(struct crash_mem) +
+		(mem_rngs->max_nr_ranges * sizeof(struct range)));
+
+	/*
+	 * Memory is allocated in size multiple of MEM_RANGE_CHUNK_SZ.
+	 * So, align to get the actual length.
+	 */
+	return ALIGN(size, MEM_RANGE_CHUNK_SZ);
+}
+
+/**
+ * __add_mem_range - add a memory range to memory ranges list.
+ * @mem_ranges:      Range list to add the memory range to.
+ * @base:            Base address of the range to add.
+ * @size:            Size of the memory range to add.
+ *
+ * (Re)allocates memory, if needed.
+ *
+ * Returns 0 on success, negative errno on error.
+ */
+static int __add_mem_range(struct crash_mem **mem_ranges, u64 base, u64 size)
+{
+	struct crash_mem *mem_rngs = *mem_ranges;
+
+	if (!mem_rngs || (mem_rngs->nr_ranges == mem_rngs->max_nr_ranges)) {
+		mem_rngs = realloc_mem_ranges(mem_ranges);
+		if (!mem_rngs)
+			return -ENOMEM;
+	}
+
+	mem_rngs->ranges[mem_rngs->nr_ranges].start = base;
+	mem_rngs->ranges[mem_rngs->nr_ranges].end = base + size - 1;
+	pr_debug("Added memory range [%#016llx - %#016llx] at index %d\n",
+		 base, base + size - 1, mem_rngs->nr_ranges);
+	mem_rngs->nr_ranges++;
+	return 0;
+}
+
+/**
+ * __merge_memory_ranges - Merges the given memory ranges list.
+ * @mem_rngs:              Range list to merge.
+ *
+ * Assumes a sorted range list.
+ *
+ * Returns nothing.
+ */
+static void __merge_memory_ranges(struct crash_mem *mem_rngs)
+{
+	struct range *ranges;
+	int i, idx;
+
+	if (!mem_rngs || mem_rngs->nr_ranges <= 1)
+		return;
+
+	idx = 0;
+	ranges = mem_rngs->ranges;
+	for (i = 1; i < mem_rngs->nr_ranges; i++) {
+		if (ranges[i].start <= (ranges[idx].end + 1))
+			ranges[idx].end = max(ranges[idx].end, ranges[i].end);
+		else {
+			idx++;
+			ranges[idx] = ranges[i];
+		}
+	}
+	mem_rngs->nr_ranges = idx + 1;
+}
+
+/* cmp_func_t callback to sort ranges with sort() */
+static int rngcmp(const void *_x, const void *_y)
+{
+	const struct range *x = _x, *y = _y;
+
+	if (x->start > y->start)
+		return 1;
+	if (x->start < y->start)
+		return -1;
+	return 0;
+}
+
+/**
+ * sort_memory_ranges - Sorts the given memory ranges list.
+ * @mem_rngs:           Range list to sort.
+ * @merge:              If true, merge the list after sorting.
+ *
+ * Returns nothing.
+ */
+void sort_memory_ranges(struct crash_mem *mem_rngs, bool merge)
+{
+	int i;
+
+	if (!mem_rngs)
+		return;
+
+	/* Sort the ranges in-place */
+	sort(&(mem_rngs->ranges[0]), mem_rngs->nr_ranges,
+	     sizeof(mem_rngs->ranges[0]), rngcmp, NULL);
+
+	if (merge)
+		__merge_memory_ranges(mem_rngs);
+
+	/* For debugging purpose */
+	pr_debug("Memory ranges:\n");
+	for (i = 0; i < mem_rngs->nr_ranges; i++) {
+		pr_debug("\t[%03d][%#016llx - %#016llx]\n", i,
+			 mem_rngs->ranges[i].start,
+			 mem_rngs->ranges[i].end);
+	}
+}
+
+/**
+ * realloc_mem_ranges - reallocate mem_ranges with size incremented
+ *                      by MEM_RANGE_CHUNK_SZ. Frees up the old memory,
+ *                      if memory allocation fails.
+ * @mem_ranges:         Memory ranges to reallocate.
+ *
+ * Returns pointer to reallocated memory on success, NULL otherwise.
+ */
+struct crash_mem *realloc_mem_ranges(struct crash_mem **mem_ranges)
+{
+	struct crash_mem *mem_rngs = *mem_ranges;
+	unsigned int nr_ranges;
+	size_t size;
+
+	size = get_mem_rngs_size(mem_rngs);
+	nr_ranges = mem_rngs ? mem_rngs->nr_ranges : 0;
+
+	size += MEM_RANGE_CHUNK_SZ;
+	mem_rngs = krealloc(*mem_ranges, size, GFP_KERNEL);
+	if (!mem_rngs) {
+		kfree(*mem_ranges);
+		*mem_ranges = NULL;
+		return NULL;
+	}
+
+	mem_rngs->nr_ranges = nr_ranges;
+	mem_rngs->max_nr_ranges = get_max_nr_ranges(size);
+	*mem_ranges = mem_rngs;
+
+	return mem_rngs;
+}
+
+/**
+ * add_mem_range - Updates existing memory range, if there is an overlap.
+ *                 Else, adds a new memory range.
+ * @mem_ranges:    Range list to add the memory range to.
+ * @base:          Base address of the range to add.
+ * @size:          Size of the memory range to add.
+ *
+ * (Re)allocates memory, if needed.
+ *
+ * Returns 0 on success, negative errno on error.
+ */
+int add_mem_range(struct crash_mem **mem_ranges, u64 base, u64 size)
+{
+	struct crash_mem *mem_rngs = *mem_ranges;
+	u64 mstart, mend, end;
+	unsigned int i;
+
+	if (!size)
+		return 0;
+
+	end = base + size - 1;
+
+	if (!mem_rngs || !(mem_rngs->nr_ranges))
+		return __add_mem_range(mem_ranges, base, size);
+
+	for (i = 0; i < mem_rngs->nr_ranges; i++) {
+		mstart = mem_rngs->ranges[i].start;
+		mend = mem_rngs->ranges[i].end;
+		if (base < mend && end > mstart) {
+			if (base < mstart)
+				mem_rngs->ranges[i].start = base;
+			if (end > mend)
+				mem_rngs->ranges[i].end = end;
+			return 0;
+		}
+	}
+
+	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.
+ */
+static int add_tce_mem_ranges(struct crash_mem **mem_ranges)
+{
+	struct device_node *dn = NULL;
+	int ret = 0;
+
+	for_each_node_by_type(dn, "pci") {
+		u64 base;
+		u32 size;
+
+		ret = of_property_read_u64(dn, "linux,tce-base", &base);
+		ret |= of_property_read_u32(dn, "linux,tce-size", &size);
+		if (ret) {
+			/*
+			 * It is ok to have pci nodes without tce. So, ignore
+			 * property does not exist error.
+			 */
+			if (ret == -EINVAL) {
+				ret = 0;
+				continue;
+			}
+			break;
+		}
+
+		ret = add_mem_range(mem_ranges, base, size);
+		if (ret)
+			break;
+	}
+
+	of_node_put(dn);
+	return ret;
+}
+
+/**
+ * add_initrd_mem_range - Adds initrd range to the given memory ranges list,
+ *                        if the initrd was retained.
+ * @mem_ranges:           Range list to add the memory range to.
+ *
+ * Returns 0 on success, negative errno on error.
+ */
+static int add_initrd_mem_range(struct crash_mem **mem_ranges)
+{
+	u64 base, end;
+	int ret;
+
+	/* This range means something, only if initrd was retained */
+	if (!strstr(saved_command_line, "retain_initrd"))
+		return 0;
+
+	ret = of_property_read_u64(of_chosen, "linux,initrd-start", &base);
+	ret |= of_property_read_u64(of_chosen, "linux,initrd-end", &end);
+	if (!ret)
+		ret = add_mem_range(mem_ranges, base, end - base + 1);
+
+	return ret;
+}
+
+/**
+ * add_htab_mem_range - Adds htab range to the given memory ranges list,
+ *                      if it exists
+ * @mem_ranges:         Range list to add the memory range to.
+ *
+ * Returns 0 on success, negative errno on error.
+ */
+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
+ *                        memory ranges list.
+ * @mem_ranges:           Range list to add the memory range to.
+ *
+ * Returns 0 on success, negative errno on error.
+ */
+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.
+ */
+static int add_rtas_mem_range(struct crash_mem **mem_ranges)
+{
+	struct device_node *dn;
+	u32 base, size;
+	int ret = 0;
+
+	dn = of_find_node_by_path("/rtas");
+	if (!dn)
+		return 0;
+
+	ret = of_property_read_u32(dn, "linux,rtas-base", &base);
+	ret |= of_property_read_u32(dn, "rtas-size", &size);
+	if (!ret)
+		ret = add_mem_range(mem_ranges, base, size);
+
+	of_node_put(dn);
+	return ret;
+}
+
+/**
+ * add_opal_mem_range - Adds OPAL 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.
+ */
+static int add_opal_mem_range(struct crash_mem **mem_ranges)
+{
+	struct device_node *dn;
+	u64 base, size;
+	int ret;
+
+	dn = of_find_node_by_path("/ibm,opal");
+	if (!dn)
+		return 0;
+
+	ret = of_property_read_u64(dn, "opal-base-address", &base);
+	ret |= of_property_read_u64(dn, "opal-runtime-size", &size);
+	if (!ret)
+		ret = add_mem_range(mem_ranges, base, size);
+
+	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.
+ * @mem_ranges:              Range list to add the memory ranges to.
+ *
+ * Returns 0 on success, negative errno on error.
+ */
+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("/");
+	const __be32 *prop;
+
+	prop = of_get_property(root, "reserved-ranges", &len);
+	n_mem_addr_cells = of_n_addr_cells(root);
+	n_mem_size_cells = of_n_size_cells(root);
+	of_node_put(root);
+	if (!prop)
+		return 0;
+
+	cells = n_mem_addr_cells + n_mem_size_cells;
+
+	/* Each reserved range is an (address,size) pair */
+	for (i = 0; i < (len / (sizeof(u32) * cells)); i++) {
+		u64 base, size;
+
+		base = of_read_number(prop + (i * cells), n_mem_addr_cells);
+		size = of_read_number(prop + (i * cells) + n_mem_addr_cells,
+				      n_mem_size_cells);
+
+		ret = add_mem_range(mem_ranges, base, size);
+		if (ret)
+			break;
+	}
+
+	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, i;
+
+	/*
+	 * 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;
+
+	for (i = 0; i < crashk_cma_cnt; i++) {
+		ret = add_mem_range(mem_ranges, crashk_cma_ranges[i].start,
+				    crashk_cma_ranges[i].end - crashk_cma_ranges[i].start + 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
+int arch_crash_exclude_mem_range(struct crash_mem **mem_ranges,
+				 unsigned long long mstart,
+				 unsigned long long mend)
+{
+	struct crash_mem *tmem = *mem_ranges;
+
+	/* Reallocate memory ranges if there is no space to split ranges */
+	if (tmem && (tmem->nr_ranges == tmem->max_nr_ranges)) {
+		tmem = realloc_mem_ranges(mem_ranges);
+		if (!tmem)
+			return -ENOMEM;
+	}
+
+	return crash_exclude_mem_range(tmem, mstart, mend);
+}
+
+/**
+ * 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;
+	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);
+	}
+
+	ret = crash_exclude_core_ranges(mem_ranges);
+	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;
+}
+#endif /* CONFIG_CRASH_DUMP */
diff --git a/arch/powerpc/kexec/relocate_32.S b/arch/powerpc/kexec/relocate_32.S
new file mode 100644
index 000000000..dd86e3383
--- /dev/null
+++ b/arch/powerpc/kexec/relocate_32.S
@@ -0,0 +1,499 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * This file contains kexec low-level functions.
+ *
+ * Copyright (C) 2002-2003 Eric Biederman  <ebiederm@xmission.com>
+ * GameCube/ppc32 port Copyright (C) 2004 Albert Herranz
+ * PPC44x port. Copyright (C) 2011,  IBM Corporation
+ * 		Author: Suzuki Poulose <suzuki@in.ibm.com>
+ */
+
+#include <linux/objtool.h>
+#include <asm/reg.h>
+#include <asm/page.h>
+#include <asm/mmu.h>
+#include <asm/ppc_asm.h>
+#include <asm/kexec.h>
+
+	.text
+
+	/*
+	 * Must be relocatable PIC code callable as a C function.
+	 */
+	.globl relocate_new_kernel
+relocate_new_kernel:
+	/* r3 = page_list   */
+	/* r4 = reboot_code_buffer */
+	/* r5 = start_address      */
+
+#ifdef CONFIG_PPC_85xx
+
+	mr	r29, r3
+	mr	r30, r4
+	mr	r31, r5
+
+#define ENTRY_MAPPING_KEXEC_SETUP
+#include <kernel/85xx_entry_mapping.S>
+#undef ENTRY_MAPPING_KEXEC_SETUP
+
+	mr      r3, r29
+	mr      r4, r30
+	mr      r5, r31
+
+	li	r0, 0
+#elif defined(CONFIG_44x)
+
+	/* Save our parameters */
+	mr	r29, r3
+	mr	r30, r4
+	mr	r31, r5
+
+#ifdef CONFIG_PPC_47x
+	/* Check for 47x cores */
+	mfspr	r3,SPRN_PVR
+	srwi	r3,r3,16
+	cmplwi	cr0,r3,PVR_476FPE@h
+	beq	setup_map_47x
+	cmplwi	cr0,r3,PVR_476@h
+	beq	setup_map_47x
+	cmplwi	cr0,r3,PVR_476_ISS@h
+	beq	setup_map_47x
+#endif /* CONFIG_PPC_47x */
+
+/*
+ * Code for setting up 1:1 mapping for PPC440x for KEXEC
+ *
+ * We cannot switch off the MMU on PPC44x.
+ * So we:
+ * 1) Invalidate all the mappings except the one we are running from.
+ * 2) Create a tmp mapping for our code in the other address space(TS) and
+ *    jump to it. Invalidate the entry we started in.
+ * 3) Create a 1:1 mapping for 0-2GiB in chunks of 256M in original TS.
+ * 4) Jump to the 1:1 mapping in original TS.
+ * 5) Invalidate the tmp mapping.
+ *
+ * - Based on the kexec support code for FSL BookE
+ *
+ */
+
+	/*
+	 * Load the PID with kernel PID (0).
+	 * Also load our MSR_IS and TID to MMUCR for TLB search.
+	 */
+	li	r3, 0
+	mtspr	SPRN_PID, r3
+	mfmsr	r4
+	andi.	r4,r4,MSR_IS@l
+	beq	wmmucr
+	oris	r3,r3,PPC44x_MMUCR_STS@h
+wmmucr:
+	mtspr	SPRN_MMUCR,r3
+	sync
+
+	/*
+	 * Invalidate all the TLB entries except the current entry
+	 * where we are running from
+	 */
+	bcl	20,31,$+4			/* Find our address */
+0:	mflr	r5				/* Make it accessible */
+	tlbsx	r23,0,r5			/* Find entry we are in */
+	li	r4,0				/* Start at TLB entry 0 */
+	li	r3,0				/* Set PAGEID inval value */
+1:	cmpw	r23,r4				/* Is this our entry? */
+	beq	skip				/* If so, skip the inval */
+	tlbwe	r3,r4,PPC44x_TLB_PAGEID		/* If not, inval the entry */
+skip:
+	addi	r4,r4,1				/* Increment */
+	cmpwi	r4,64				/* Are we done?	*/
+	bne	1b				/* If not, repeat */
+	isync
+
+	/* Create a temp mapping and jump to it */
+	andi.	r6, r23, 1		/* Find the index to use */
+	addi	r24, r6, 1		/* r24 will contain 1 or 2 */
+
+	mfmsr	r9			/* get the MSR */
+	rlwinm	r5, r9, 27, 31, 31	/* Extract the MSR[IS] */
+	xori	r7, r5, 1		/* Use the other address space */
+
+	/* Read the current mapping entries */
+	tlbre	r3, r23, PPC44x_TLB_PAGEID
+	tlbre	r4, r23, PPC44x_TLB_XLAT
+	tlbre	r5, r23, PPC44x_TLB_ATTRIB
+
+	/* Save our current XLAT entry */
+	mr	r25, r4
+
+	/* Extract the TLB PageSize */
+	li	r10, 1 			/* r10 will hold PageSize */
+	rlwinm	r11, r3, 0, 24, 27	/* bits 24-27 */
+
+	/* XXX: As of now we use 256M, 4K pages */
+	cmpwi	r11, PPC44x_TLB_256M
+	bne	tlb_4k
+	rotlwi	r10, r10, 28		/* r10 = 256M */
+	b	write_out
+tlb_4k:
+	cmpwi	r11, PPC44x_TLB_4K
+	bne	default
+	rotlwi	r10, r10, 12		/* r10 = 4K */
+	b	write_out
+default:
+	rotlwi	r10, r10, 10		/* r10 = 1K */
+
+write_out:
+	/*
+	 * Write out the tmp 1:1 mapping for this code in other address space
+	 * Fixup  EPN = RPN , TS=other address space
+	 */
+	insrwi	r3, r7, 1, 23		/* Bit 23 is TS for PAGEID field */
+
+	/* Write out the tmp mapping entries */
+	tlbwe	r3, r24, PPC44x_TLB_PAGEID
+	tlbwe	r4, r24, PPC44x_TLB_XLAT
+	tlbwe	r5, r24, PPC44x_TLB_ATTRIB
+
+	subi	r11, r10, 1		/* PageOffset Mask = PageSize - 1 */
+	not	r10, r11		/* Mask for PageNum */
+
+	/* Switch to other address space in MSR */
+	insrwi	r9, r7, 1, 26		/* Set MSR[IS] = r7 */
+
+	bcl	20,31,$+4
+1:	mflr	r8
+	addi	r8, r8, (2f-1b)		/* Find the target offset */
+
+	/* Jump to the tmp mapping */
+	mtspr	SPRN_SRR0, r8
+	mtspr	SPRN_SRR1, r9
+	rfi
+
+2:
+	/* Invalidate the entry we were executing from */
+	li	r3, 0
+	tlbwe	r3, r23, PPC44x_TLB_PAGEID
+
+	/* attribute fields. rwx for SUPERVISOR mode */
+	li	r5, 0
+	ori	r5, r5, (PPC44x_TLB_SW | PPC44x_TLB_SR | PPC44x_TLB_SX | PPC44x_TLB_G)
+
+	/* Create 1:1 mapping in 256M pages */
+	xori	r7, r7, 1			/* Revert back to Original TS */
+
+	li	r8, 0				/* PageNumber */
+	li	r6, 3				/* TLB Index, start at 3  */
+
+next_tlb:
+	rotlwi	r3, r8, 28			/* Create EPN (bits 0-3) */
+	mr	r4, r3				/* RPN = EPN  */
+	ori	r3, r3, (PPC44x_TLB_VALID | PPC44x_TLB_256M) /* SIZE = 256M, Valid */
+	insrwi	r3, r7, 1, 23			/* Set TS from r7 */
+
+	tlbwe	r3, r6, PPC44x_TLB_PAGEID	/* PageID field : EPN, V, SIZE */
+	tlbwe	r4, r6, PPC44x_TLB_XLAT		/* Address translation : RPN   */
+	tlbwe	r5, r6, PPC44x_TLB_ATTRIB	/* Attributes */
+
+	addi	r8, r8, 1			/* Increment PN */
+	addi	r6, r6, 1			/* Increment TLB Index */
+	cmpwi	r8, 8				/* Are we done ? */
+	bne	next_tlb
+	isync
+
+	/* Jump to the new mapping 1:1 */
+	li	r9,0
+	insrwi	r9, r7, 1, 26			/* Set MSR[IS] = r7 */
+
+	bcl	20,31,$+4
+1:	mflr	r8
+	and	r8, r8, r11			/* Get our offset within page */
+	addi	r8, r8, (2f-1b)
+
+	and	r5, r25, r10			/* Get our target PageNum */
+	or	r8, r8, r5			/* Target jump address */
+
+	mtspr	SPRN_SRR0, r8
+	mtspr	SPRN_SRR1, r9
+	rfi
+2:
+	/* Invalidate the tmp entry we used */
+	li	r3, 0
+	tlbwe	r3, r24, PPC44x_TLB_PAGEID
+	sync
+	b	ppc44x_map_done
+
+#ifdef CONFIG_PPC_47x
+
+	/* 1:1 mapping for 47x */
+
+setup_map_47x:
+
+	/*
+	 * Load the kernel pid (0) to PID and also to MMUCR[TID].
+	 * Also set the MSR IS->MMUCR STS
+	 */
+	li	r3, 0
+	mtspr	SPRN_PID, r3			/* Set PID */
+	mfmsr	r4				/* Get MSR */
+	andi.	r4, r4, MSR_IS@l		/* TS=1? */
+	beq	1f				/* If not, leave STS=0 */
+	oris	r3, r3, PPC47x_MMUCR_STS@h	/* Set STS=1 */
+1:	mtspr	SPRN_MMUCR, r3			/* Put MMUCR */
+	sync
+
+	/* Find the entry we are running from */
+	bcl	20,31,$+4
+2:	mflr	r23
+	tlbsx	r23, 0, r23
+	tlbre	r24, r23, 0			/* TLB Word 0 */
+	tlbre	r25, r23, 1			/* TLB Word 1 */
+	tlbre	r26, r23, 2			/* TLB Word 2 */
+
+
+	/*
+	 * Invalidates all the tlb entries by writing to 256 RPNs(r4)
+	 * of 4k page size in all  4 ways (0-3 in r3).
+	 * This would invalidate the entire UTLB including the one we are
+	 * running from. However the shadow TLB entries would help us
+	 * to continue the execution, until we flush them (rfi/isync).
+	 */
+	addis	r3, 0, 0x8000			/* specify the way */
+	addi	r4, 0, 0			/* TLB Word0 = (EPN=0, VALID = 0) */
+	addi	r5, 0, 0
+	b	clear_utlb_entry
+
+	/* Align the loop to speed things up. from head_44x.S */
+	.align	6
+
+clear_utlb_entry:
+
+	tlbwe	r4, r3, 0
+	tlbwe	r5, r3, 1
+	tlbwe	r5, r3, 2
+	addis	r3, r3, 0x2000			/* Increment the way */
+	cmpwi	r3, 0
+	bne	clear_utlb_entry
+	addis	r3, 0, 0x8000
+	addis	r4, r4, 0x100			/* Increment the EPN */
+	cmpwi	r4, 0
+	bne	clear_utlb_entry
+
+	/* Create the entries in the other address space */
+	mfmsr	r5
+	rlwinm	r7, r5, 27, 31, 31		/* Get the TS (Bit 26) from MSR */
+	xori	r7, r7, 1			/* r7 = !TS */
+
+	insrwi	r24, r7, 1, 21			/* Change the TS in the saved TLB word 0 */
+
+	/*
+	 * write out the TLB entries for the tmp mapping
+	 * Use way '0' so that we could easily invalidate it later.
+	 */
+	lis	r3, 0x8000			/* Way '0' */
+
+	tlbwe	r24, r3, 0
+	tlbwe	r25, r3, 1
+	tlbwe	r26, r3, 2
+
+	/* Update the msr to the new TS */
+	insrwi	r5, r7, 1, 26
+
+	bcl	20,31,$+4
+1:	mflr	r6
+	addi	r6, r6, (2f-1b)
+
+	mtspr	SPRN_SRR0, r6
+	mtspr	SPRN_SRR1, r5
+	rfi
+
+	/*
+	 * Now we are in the tmp address space.
+	 * Create a 1:1 mapping for 0-2GiB in the original TS.
+	 */
+2:
+	li	r3, 0
+	li	r4, 0				/* TLB Word 0 */
+	li	r5, 0				/* TLB Word 1 */
+	li	r6, 0
+	ori	r6, r6, PPC47x_TLB2_S_RWX	/* TLB word 2 */
+
+	li	r8, 0				/* PageIndex */
+
+	xori	r7, r7, 1			/* revert back to original TS */
+
+write_utlb:
+	rotlwi	r5, r8, 28			/* RPN = PageIndex * 256M */
+						/* ERPN = 0 as we don't use memory above 2G */
+
+	mr	r4, r5				/* EPN = RPN */
+	ori	r4, r4, (PPC47x_TLB0_VALID | PPC47x_TLB0_256M)
+	insrwi	r4, r7, 1, 21			/* Insert the TS to Word 0 */
+
+	tlbwe	r4, r3, 0			/* Write out the entries */
+	tlbwe	r5, r3, 1
+	tlbwe	r6, r3, 2
+	addi	r8, r8, 1
+	cmpwi	r8, 8				/* Have we completed ? */
+	bne	write_utlb
+
+	/* make sure we complete the TLB write up */
+	isync
+
+	/*
+	 * Prepare to jump to the 1:1 mapping.
+	 * 1) Extract page size of the tmp mapping
+	 *    DSIZ = TLB_Word0[22:27]
+	 * 2) Calculate the physical address of the address
+	 *    to jump to.
+	 */
+	rlwinm	r10, r24, 0, 22, 27
+
+	cmpwi	r10, PPC47x_TLB0_4K
+	li	r10, 0x1000			/* r10 = 4k */
+	beq	0f
+
+	/* Defaults to 256M */
+	lis	r10, 0x1000
+
+0:	bcl	20,31,$+4
+1:	mflr	r4
+	addi	r4, r4, (2f-1b)			/* virtual address  of 2f */
+
+	subi	r11, r10, 1			/* offsetmask = Pagesize - 1 */
+	not	r10, r11			/* Pagemask = ~(offsetmask) */
+
+	and	r5, r25, r10			/* Physical page */
+	and	r6, r4, r11			/* offset within the current page */
+
+	or	r5, r5, r6			/* Physical address for 2f */
+
+	/* Switch the TS in MSR to the original one */
+	mfmsr	r8
+	insrwi	r8, r7, 1, 26
+
+	mtspr	SPRN_SRR1, r8
+	mtspr	SPRN_SRR0, r5
+	rfi
+
+2:
+	/* Invalidate the tmp mapping */
+	lis	r3, 0x8000			/* Way '0' */
+
+	clrrwi	r24, r24, 12			/* Clear the valid bit */
+	tlbwe	r24, r3, 0
+	tlbwe	r25, r3, 1
+	tlbwe	r26, r3, 2
+
+	/* Make sure we complete the TLB write and flush the shadow TLB */
+	isync
+
+#endif
+
+ppc44x_map_done:
+
+
+	/* Restore the parameters */
+	mr	r3, r29
+	mr	r4, r30
+	mr	r5, r31
+
+	li	r0, 0
+#else
+	li	r0, 0
+
+	/*
+	 * Set Machine Status Register to a known status,
+	 * switch the MMU off and jump to 1: in a single step.
+	 */
+
+	mr	r8, r0
+	ori     r8, r8, MSR_RI|MSR_ME
+	mtspr	SPRN_SRR1, r8
+	addi	r8, r4, 1f - relocate_new_kernel
+	mtspr	SPRN_SRR0, r8
+	sync
+	rfi
+
+1:
+#endif
+	/* from this point address translation is turned off */
+	/* and interrupts are disabled */
+
+	/* set a new stack at the bottom of our page... */
+	/* (not really needed now) */
+	addi	r1, r4, KEXEC_CONTROL_PAGE_SIZE - 8 /* for LR Save+Back Chain */
+	stw	r0, 0(r1)
+
+	/* Do the copies */
+	li	r6, 0 /* checksum */
+	mr	r0, r3
+	b	1f
+
+0:	/* top, read another word for the indirection page */
+	lwzu	r0, 4(r3)
+
+1:
+	/* is it a destination page? (r8) */
+	rlwinm.	r7, r0, 0, 31, 31 /* IND_DESTINATION (1<<0) */
+	beq	2f
+
+	rlwinm	r8, r0, 0, 0, 19 /* clear kexec flags, page align */
+	b	0b
+
+2:	/* is it an indirection page? (r3) */
+	rlwinm.	r7, r0, 0, 30, 30 /* IND_INDIRECTION (1<<1) */
+	beq	2f
+
+	rlwinm	r3, r0, 0, 0, 19 /* clear kexec flags, page align */
+	subi	r3, r3, 4
+	b	0b
+
+2:	/* are we done? */
+	rlwinm.	r7, r0, 0, 29, 29 /* IND_DONE (1<<2) */
+	beq	2f
+	b	3f
+
+2:	/* is it a source page? (r9) */
+	rlwinm.	r7, r0, 0, 28, 28 /* IND_SOURCE (1<<3) */
+	beq	0b
+
+	rlwinm	r9, r0, 0, 0, 19 /* clear kexec flags, page align */
+
+	li	r7, PAGE_SIZE / 4
+	mtctr   r7
+	subi    r9, r9, 4
+	subi    r8, r8, 4
+9:
+	lwzu    r0, 4(r9)  /* do the copy */
+	xor	r6, r6, r0
+	stwu    r0, 4(r8)
+	dcbst	0, r8
+	sync
+	icbi	0, r8
+	bdnz    9b
+
+	addi    r9, r9, 4
+	addi    r8, r8, 4
+	b	0b
+
+3:
+
+	/* To be certain of avoiding problems with self-modifying code
+	 * execute a serializing instruction here.
+	 */
+	isync
+	sync
+
+	mfspr	r3, SPRN_PIR /* current core we are running on */
+	mr	r4, r5 /* load physical address of chunk called */
+
+	/* jump to the entry point, usually the setup routine */
+	mtlr	r5
+	blrl
+
+1:	b	1b
+
+relocate_new_kernel_end:
+
+	.globl relocate_new_kernel_size
+relocate_new_kernel_size:
+	.long relocate_new_kernel_end - relocate_new_kernel
diff --git a/arch/powerpc/kexec/vmcore_info.c b/arch/powerpc/kexec/vmcore_info.c
new file mode 100644
index 000000000..2b65d2adc
--- /dev/null
+++ b/arch/powerpc/kexec/vmcore_info.c
@@ -0,0 +1,32 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/vmcore_info.h>
+#include <asm/pgalloc.h>
+
+void arch_crash_save_vmcoreinfo(void)
+{
+
+#ifdef CONFIG_NUMA
+	VMCOREINFO_SYMBOL(node_data);
+	VMCOREINFO_LENGTH(node_data, MAX_NUMNODES);
+#endif
+#ifndef CONFIG_NUMA
+	VMCOREINFO_SYMBOL(contig_page_data);
+#endif
+#if defined(CONFIG_PPC64) && defined(CONFIG_SPARSEMEM_VMEMMAP)
+	VMCOREINFO_SYMBOL(vmemmap_list);
+	VMCOREINFO_SYMBOL(mmu_vmemmap_psize);
+	VMCOREINFO_SYMBOL(mmu_psize_defs);
+	VMCOREINFO_STRUCT_SIZE(vmemmap_backing);
+	VMCOREINFO_OFFSET(vmemmap_backing, list);
+	VMCOREINFO_OFFSET(vmemmap_backing, phys);
+	VMCOREINFO_OFFSET(vmemmap_backing, virt_addr);
+	VMCOREINFO_STRUCT_SIZE(mmu_psize_def);
+	VMCOREINFO_OFFSET(mmu_psize_def, shift);
+#endif
+	VMCOREINFO_SYMBOL(cur_cpu_spec);
+	VMCOREINFO_OFFSET(cpu_spec, cpu_features);
+	VMCOREINFO_OFFSET(cpu_spec, mmu_features);
+	vmcoreinfo_append_str("NUMBER(RADIX_MMU)=%d\n", early_radix_enabled());
+	vmcoreinfo_append_str("KERNELOFFSET=%lx\n", kaslr_offset());
+}