1 files changed, 555 insertions, 47 deletions

diff --git a/mm/memblock.c b/mm/memblock.c
index d09136e040d3..154f1d73b61f 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -16,6 +16,12 @@
 #include <linux/kmemleak.h>
 #include <linux/seq_file.h>
 #include <linux/memblock.h>
+#include <linux/mutex.h>
+
+#ifdef CONFIG_KEXEC_HANDOVER
+#include <linux/libfdt.h>
+#include <linux/kexec_handover.h>
+#endif /* CONFIG_KEXEC_HANDOVER */
 
 #include <asm/sections.h>
 #include <linux/io.h>
@@ -106,6 +112,13 @@ unsigned long min_low_pfn;
 unsigned long max_pfn;
 unsigned long long max_possible_pfn;
 
+#ifdef CONFIG_MEMBLOCK_KHO_SCRATCH
+/* When set to true, only allocate from MEMBLOCK_KHO_SCRATCH ranges */
+static bool kho_scratch_only;
+#else
+#define kho_scratch_only false
+#endif
+
 static struct memblock_region memblock_memory_init_regions[INIT_MEMBLOCK_MEMORY_REGIONS] __initdata_memblock;
 static struct memblock_region memblock_reserved_init_regions[INIT_MEMBLOCK_RESERVED_REGIONS] __initdata_memblock;
 #ifdef CONFIG_HAVE_MEMBLOCK_PHYS_MAP
@@ -114,12 +127,10 @@ static struct memblock_region memblock_physmem_init_regions[INIT_PHYSMEM_REGIONS
 
 struct memblock memblock __initdata_memblock = {
 	.memory.regions		= memblock_memory_init_regions,
-	.memory.cnt		= 1,	/* empty dummy entry */
 	.memory.max		= INIT_MEMBLOCK_MEMORY_REGIONS,
 	.memory.name		= "memory",
 
 	.reserved.regions	= memblock_reserved_init_regions,
-	.reserved.cnt		= 1,	/* empty dummy entry */
 	.reserved.max		= INIT_MEMBLOCK_RESERVED_REGIONS,
 	.reserved.name		= "reserved",
 
@@ -130,7 +141,6 @@ struct memblock memblock __initdata_memblock = {
 #ifdef CONFIG_HAVE_MEMBLOCK_PHYS_MAP
 struct memblock_type physmem = {
 	.regions		= memblock_physmem_init_regions,
-	.cnt			= 1,	/* empty dummy entry */
 	.max			= INIT_PHYSMEM_REGIONS,
 	.name			= "physmem",
 };
@@ -168,6 +178,10 @@ bool __init_memblock memblock_has_mirror(void)
 
 static enum memblock_flags __init_memblock choose_memblock_flags(void)
 {
+	/* skip non-scratch memory for kho early boot allocations */
+	if (kho_scratch_only)
+		return MEMBLOCK_KHO_SCRATCH;
+
 	return system_has_some_mirror ? MEMBLOCK_MIRROR : MEMBLOCK_NONE;
 }
 
@@ -197,8 +211,8 @@ bool __init_memblock memblock_overlaps_region(struct memblock_type *type,
 	for (i = 0; i < type->cnt; i++)
 		if (memblock_addrs_overlap(base, size, type->regions[i].base,
 					   type->regions[i].size))
-			break;
-	return i < type->cnt;
+			return true;
+	return false;
 }
 
 /**
@@ -356,7 +370,6 @@ static void __init_memblock memblock_remove_region(struct memblock_type *type, u
 	/* Special case for empty arrays */
 	if (type->cnt == 0) {
 		WARN_ON(type->total_size != 0);
-		type->cnt = 1;
 		type->regions[0].base = 0;
 		type->regions[0].size = 0;
 		type->regions[0].flags = 0;
@@ -460,7 +473,14 @@ static int __init_memblock memblock_double_array(struct memblock_type *type,
 				min(new_area_start, memblock.current_limit),
 				new_alloc_size, PAGE_SIZE);
 
-		new_array = addr ? __va(addr) : NULL;
+		if (addr) {
+			/* The memory may not have been accepted, yet. */
+			accept_memory(addr, new_alloc_size);
+
+			new_array = __va(addr);
+		} else {
+			new_array = NULL;
+		}
 	}
 	if (!addr) {
 		pr_err("memblock: Failed to double %s array from %ld to %ld entries !\n",
@@ -495,7 +515,7 @@ static int __init_memblock memblock_double_array(struct memblock_type *type,
 	 * needn't do it
 	 */
 	if (!use_slab)
-		BUG_ON(memblock_reserve(addr, new_alloc_size));
+		BUG_ON(memblock_reserve_kern(addr, new_alloc_size));
 
 	/* Update slab flag */
 	*in_slab = use_slab;
@@ -600,12 +620,13 @@ static int __init_memblock memblock_add_range(struct memblock_type *type,
 
 	/* special case for empty array */
 	if (type->regions[0].size == 0) {
-		WARN_ON(type->cnt != 1 || type->total_size);
+		WARN_ON(type->cnt != 0 || type->total_size);
 		type->regions[0].base = base;
 		type->regions[0].size = size;
 		type->regions[0].flags = flags;
 		memblock_set_region_node(&type->regions[0], nid);
 		type->total_size = size;
+		type->cnt = 1;
 		return 0;
 	}
 
@@ -644,7 +665,7 @@ repeat:
 #ifdef CONFIG_NUMA
 			WARN_ON(nid != memblock_get_region_node(rgn));
 #endif
-			WARN_ON(flags != rgn->flags);
+			WARN_ON(flags != MEMBLOCK_NONE && flags != rgn->flags);
 			nr_new++;
 			if (insert) {
 				if (start_rgn == -1)
@@ -738,7 +759,7 @@ int __init_memblock memblock_add(phys_addr_t base, phys_addr_t size)
 /**
  * memblock_validate_numa_coverage - check if amount of memory with
  * no node ID assigned is less than a threshold
- * @threshold_bytes: maximal number of pages that can have unassigned node
+ * @threshold_bytes: maximal memory size that can have unassigned node
  * ID (in bytes).
  *
  * A buggy firmware may report memory that does not belong to any node.
@@ -754,11 +775,11 @@ bool __init_memblock memblock_validate_numa_coverage(unsigned long threshold_byt
 
 	/* calculate lose page */
 	for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) {
-		if (nid == NUMA_NO_NODE)
+		if (!numa_valid_node(nid))
 			nr_pages += end_pfn - start_pfn;
 	}
 
-	if ((nr_pages << PAGE_SHIFT) >= threshold_bytes) {
+	if ((nr_pages << PAGE_SHIFT) > threshold_bytes) {
 		mem_size_mb = memblock_phys_mem_size() >> 20;
 		pr_err("NUMA: no nodes coverage for %luMB of %luMB RAM\n",
 		       (nr_pages << PAGE_SHIFT) >> 20, mem_size_mb);
@@ -780,7 +801,8 @@ bool __init_memblock memblock_validate_numa_coverage(unsigned long threshold_byt
  * Walk @type and ensure that regions don't cross the boundaries defined by
  * [@base, @base + @size).  Crossing regions are split at the boundaries,
  * which may create at most two more regions.  The index of the first
- * region inside the range is returned in *@start_rgn and end in *@end_rgn.
+ * region inside the range is returned in *@start_rgn and the index of the
+ * first region after the range is returned in *@end_rgn.
  *
  * Return:
  * 0 on success, -errno on failure.
@@ -903,14 +925,15 @@ int __init_memblock memblock_phys_free(phys_addr_t base, phys_addr_t size)
 	return memblock_remove_range(&memblock.reserved, base, size);
 }
 
-int __init_memblock memblock_reserve(phys_addr_t base, phys_addr_t size)
+int __init_memblock __memblock_reserve(phys_addr_t base, phys_addr_t size,
+				       int nid, enum memblock_flags flags)
 {
 	phys_addr_t end = base + size - 1;
 
-	memblock_dbg("%s: [%pa-%pa] %pS\n", __func__,
-		     &base, &end, (void *)_RET_IP_);
+	memblock_dbg("%s: [%pa-%pa] nid=%d flags=%x %pS\n", __func__,
+		     &base, &end, nid, flags, (void *)_RET_IP_);
 
-	return memblock_add_range(&memblock.reserved, base, size, MAX_NUMNODES, 0);
+	return memblock_add_range(&memblock.reserved, base, size, nid, flags);
 }
 
 #ifdef CONFIG_HAVE_MEMBLOCK_PHYS_MAP
@@ -925,6 +948,40 @@ int __init_memblock memblock_physmem_add(phys_addr_t base, phys_addr_t size)
 }
 #endif
 
+#ifdef CONFIG_MEMBLOCK_KHO_SCRATCH
+__init void memblock_set_kho_scratch_only(void)
+{
+	kho_scratch_only = true;
+}
+
+__init void memblock_clear_kho_scratch_only(void)
+{
+	kho_scratch_only = false;
+}
+
+__init void memmap_init_kho_scratch_pages(void)
+{
+	phys_addr_t start, end;
+	unsigned long pfn;
+	int nid;
+	u64 i;
+
+	if (!IS_ENABLED(CONFIG_DEFERRED_STRUCT_PAGE_INIT))
+		return;
+
+	/*
+	 * Initialize struct pages for free scratch memory.
+	 * The struct pages for reserved scratch memory will be set up in
+	 * reserve_bootmem_region()
+	 */
+	__for_each_mem_range(i, &memblock.memory, NULL, NUMA_NO_NODE,
+			     MEMBLOCK_KHO_SCRATCH, &start, &end, &nid) {
+		for (pfn = PFN_UP(start); pfn < PFN_DOWN(end); pfn++)
+			init_deferred_page(pfn, nid);
+	}
+}
+#endif
+
 /**
  * memblock_setclr_flag - set or clear flag for a memory region
  * @type: memblock type to set/clear flag for
@@ -1050,6 +1107,36 @@ int __init_memblock memblock_reserved_mark_noinit(phys_addr_t base, phys_addr_t
 				    MEMBLOCK_RSRV_NOINIT);
 }
 
+/**
+ * memblock_mark_kho_scratch - Mark a memory region as MEMBLOCK_KHO_SCRATCH.
+ * @base: the base phys addr of the region
+ * @size: the size of the region
+ *
+ * Only memory regions marked with %MEMBLOCK_KHO_SCRATCH will be considered
+ * for allocations during early boot with kexec handover.
+ *
+ * Return: 0 on success, -errno on failure.
+ */
+__init int memblock_mark_kho_scratch(phys_addr_t base, phys_addr_t size)
+{
+	return memblock_setclr_flag(&memblock.memory, base, size, 1,
+				    MEMBLOCK_KHO_SCRATCH);
+}
+
+/**
+ * memblock_clear_kho_scratch - Clear MEMBLOCK_KHO_SCRATCH flag for a
+ * specified region.
+ * @base: the base phys addr of the region
+ * @size: the size of the region
+ *
+ * Return: 0 on success, -errno on failure.
+ */
+__init int memblock_clear_kho_scratch(phys_addr_t base, phys_addr_t size)
+{
+	return memblock_setclr_flag(&memblock.memory, base, size, 0,
+				    MEMBLOCK_KHO_SCRATCH);
+}
+
 static bool should_skip_region(struct memblock_type *type,
 			       struct memblock_region *m,
 			       int nid, int flags)
@@ -1061,7 +1148,7 @@ static bool should_skip_region(struct memblock_type *type,
 		return false;
 
 	/* only memory regions are associated with nodes, check it */
-	if (nid != NUMA_NO_NODE && nid != m_nid)
+	if (numa_valid_node(nid) && nid != m_nid)
 		return true;
 
 	/* skip hotpluggable memory regions if needed */
@@ -1081,6 +1168,13 @@ static bool should_skip_region(struct memblock_type *type,
 	if (!(flags & MEMBLOCK_DRIVER_MANAGED) && memblock_is_driver_managed(m))
 		return true;
 
+	/*
+	 * In early alloc during kexec handover, we can only consider
+	 * MEMBLOCK_KHO_SCRATCH regions for the allocations
+	 */
+	if ((flags & MEMBLOCK_KHO_SCRATCH) && !memblock_is_kho_scratch(m))
+		return true;
+
 	return false;
 }
 
@@ -1118,10 +1212,6 @@ void __next_mem_range(u64 *idx, int nid, enum memblock_flags flags,
 	int idx_a = *idx & 0xffffffff;
 	int idx_b = *idx >> 32;
 
-	if (WARN_ONCE(nid == MAX_NUMNODES,
-	"Usage of MAX_NUMNODES is deprecated. Use NUMA_NO_NODE instead\n"))
-		nid = NUMA_NO_NODE;
-
 	for (; idx_a < type_a->cnt; idx_a++) {
 		struct memblock_region *m = &type_a->regions[idx_a];
 
@@ -1215,9 +1305,6 @@ void __init_memblock __next_mem_range_rev(u64 *idx, int nid,
 	int idx_a = *idx & 0xffffffff;
 	int idx_b = *idx >> 32;
 
-	if (WARN_ONCE(nid == MAX_NUMNODES, "Usage of MAX_NUMNODES is deprecated. Use NUMA_NO_NODE instead\n"))
-		nid = NUMA_NO_NODE;
-
 	if (*idx == (u64)ULLONG_MAX) {
 		idx_a = type_a->cnt - 1;
 		if (type_b != NULL)
@@ -1303,7 +1390,7 @@ void __init_memblock __next_mem_pfn_range(int *idx, int nid,
 
 		if (PFN_UP(r->base) >= PFN_DOWN(r->base + r->size))
 			continue;
-		if (nid == MAX_NUMNODES || nid == r_nid)
+		if (!numa_valid_node(nid) || nid == r_nid)
 			break;
 	}
 	if (*idx >= type->cnt) {
@@ -1448,8 +1535,16 @@ phys_addr_t __init memblock_alloc_range_nid(phys_addr_t size,
 	enum memblock_flags flags = choose_memblock_flags();
 	phys_addr_t found;
 
-	if (WARN_ONCE(nid == MAX_NUMNODES, "Usage of MAX_NUMNODES is deprecated. Use NUMA_NO_NODE instead\n"))
-		nid = NUMA_NO_NODE;
+	/*
+	 * Detect any accidental use of these APIs after slab is ready, as at
+	 * this moment memblock may be deinitialized already and its
+	 * internal data may be destroyed (after execution of memblock_free_all)
+	 */
+	if (WARN_ON_ONCE(slab_is_available())) {
+		void *vaddr = kzalloc_node(size, GFP_NOWAIT, nid);
+
+		return vaddr ? virt_to_phys(vaddr) : 0;
+	}
 
 	if (!align) {
 		/* Can't use WARNs this early in boot on powerpc */
@@ -1460,14 +1555,14 @@ phys_addr_t __init memblock_alloc_range_nid(phys_addr_t size,
 again:
 	found = memblock_find_in_range_node(size, align, start, end, nid,
 					    flags);
-	if (found && !memblock_reserve(found, size))
+	if (found && !__memblock_reserve(found, size, nid, MEMBLOCK_RSRV_KERN))
 		goto done;
 
-	if (nid != NUMA_NO_NODE && !exact_nid) {
+	if (numa_valid_node(nid) && !exact_nid) {
 		found = memblock_find_in_range_node(size, align, start,
 						    end, NUMA_NO_NODE,
 						    flags);
-		if (found && !memblock_reserve(found, size))
+		if (found && !memblock_reserve_kern(found, size))
 			goto done;
 	}
 
@@ -1501,7 +1596,7 @@ done:
 	 *
 	 * Accept the memory of the allocated buffer.
 	 */
-	accept_memory(found, found + size);
+	accept_memory(found, size);
 
 	return found;
 }
@@ -1576,13 +1671,6 @@ static void * __init memblock_alloc_internal(
 {
 	phys_addr_t alloc;
 
-	/*
-	 * Detect any accidental use of these APIs after slab is ready, as at
-	 * this moment memblock may be deinitialized already and its
-	 * internal data may be destroyed (after execution of memblock_free_all)
-	 */
-	if (WARN_ON_ONCE(slab_is_available()))
-		return kzalloc_node(size, GFP_NOWAIT, nid);
 
 	if (max_addr > memblock.current_limit)
 		max_addr = memblock.current_limit;
@@ -1700,6 +1788,26 @@ void * __init memblock_alloc_try_nid(
 }
 
 /**
+ * __memblock_alloc_or_panic - Try to allocate memory and panic on failure
+ * @size: size of memory block to be allocated in bytes
+ * @align: alignment of the region and block's size
+ * @func: caller func name
+ *
+ * This function attempts to allocate memory using memblock_alloc,
+ * and in case of failure, it calls panic with the formatted message.
+ * This function should not be used directly, please use the macro memblock_alloc_or_panic.
+ */
+void *__init __memblock_alloc_or_panic(phys_addr_t size, phys_addr_t align,
+				       const char *func)
+{
+	void *addr = memblock_alloc(size, align);
+
+	if (unlikely(!addr))
+		panic("%s: Failed to allocate %pap bytes\n", func, &size);
+	return addr;
+}
+
+/**
  * memblock_free_late - free pages directly to buddy allocator
  * @base: phys starting address of the  boot memory block
  * @size: size of the boot memory block in bytes
@@ -1739,6 +1847,45 @@ phys_addr_t __init_memblock memblock_reserved_size(void)
 	return memblock.reserved.total_size;
 }
 
+phys_addr_t __init_memblock memblock_reserved_kern_size(phys_addr_t limit, int nid)
+{
+	struct memblock_region *r;
+	phys_addr_t total = 0;
+
+	for_each_reserved_mem_region(r) {
+		phys_addr_t size = r->size;
+
+		if (r->base > limit)
+			break;
+
+		if (r->base + r->size > limit)
+			size = limit - r->base;
+
+		if (nid == memblock_get_region_node(r) || !numa_valid_node(nid))
+			if (r->flags & MEMBLOCK_RSRV_KERN)
+				total += size;
+	}
+
+	return total;
+}
+
+/**
+ * memblock_estimated_nr_free_pages - return estimated number of free pages
+ * from memblock point of view
+ *
+ * During bootup, subsystems might need a rough estimate of the number of free
+ * pages in the whole system, before precise numbers are available from the
+ * buddy. Especially with CONFIG_DEFERRED_STRUCT_PAGE_INIT, the numbers
+ * obtained from the buddy might be very imprecise during bootup.
+ *
+ * Return:
+ * An estimated number of free pages from memblock point of view.
+ */
+unsigned long __init memblock_estimated_nr_free_pages(void)
+{
+	return PHYS_PFN(memblock_phys_mem_size() - memblock_reserved_size());
+}
+
 /* lowest address */
 phys_addr_t __init_memblock memblock_start_of_DRAM(void)
 {
@@ -1983,7 +2130,7 @@ static void __init_memblock memblock_dump(struct memblock_type *type)
 		end = base + size - 1;
 		flags = rgn->flags;
 #ifdef CONFIG_NUMA
-		if (memblock_get_region_node(rgn) != MAX_NUMNODES)
+		if (numa_valid_node(memblock_get_region_node(rgn)))
 			snprintf(nid_buf, sizeof(nid_buf), " on node %d",
 				 memblock_get_region_node(rgn));
 #endif
@@ -2041,7 +2188,7 @@ static void __init free_memmap(unsigned long start_pfn, unsigned long end_pfn)
 	 * downwards.
 	 */
 	pg = PAGE_ALIGN(__pa(start_pg));
-	pgend = __pa(end_pg) & PAGE_MASK;
+	pgend = PAGE_ALIGN_DOWN(__pa(end_pg));
 
 	/*
 	 * If there are free pages between these, free the section of the
@@ -2135,8 +2282,10 @@ static unsigned long __init __free_memory_core(phys_addr_t start,
 				 phys_addr_t end)
 {
 	unsigned long start_pfn = PFN_UP(start);
-	unsigned long end_pfn = min_t(unsigned long,
-				      PFN_DOWN(end), max_low_pfn);
+	unsigned long end_pfn = PFN_DOWN(end);
+
+	if (!IS_ENABLED(CONFIG_HIGHMEM) && end_pfn > max_low_pfn)
+		end_pfn = max_low_pfn;
 
 	if (start_pfn >= end_pfn)
 		return 0;
@@ -2151,11 +2300,14 @@ static void __init memmap_init_reserved_pages(void)
 	struct memblock_region *region;
 	phys_addr_t start, end;
 	int nid;
+	unsigned long max_reserved;
 
 	/*
 	 * set nid on all reserved pages and also treat struct
 	 * pages for the NOMAP regions as PageReserved
 	 */
+repeat:
+	max_reserved = memblock.reserved.max;
 	for_each_mem_region(region) {
 		nid = memblock_get_region_node(region);
 		start = region->base;
@@ -2164,8 +2316,15 @@ static void __init memmap_init_reserved_pages(void)
 		if (memblock_is_nomap(region))
 			reserve_bootmem_region(start, end, nid);
 
-		memblock_set_node(start, end, &memblock.reserved, nid);
+		memblock_set_node(start, region->size, &memblock.reserved, nid);
 	}
+	/*
+	 * 'max' is changed means memblock.reserved has been doubled its
+	 * array, which may result a new reserved region before current
+	 * 'start'. Now we should repeat the procedure to set its node id.
+	 */
+	if (max_reserved != memblock.reserved.max)
+		goto repeat;
 
 	/*
 	 * initialize struct pages for reserved regions that don't have
@@ -2177,7 +2336,7 @@ static void __init memmap_init_reserved_pages(void)
 			start = region->base;
 			end = start + region->size;
 
-			if (nid == NUMA_NO_NODE || nid >= MAX_NUMNODES)
+			if (!numa_valid_node(nid))
 				nid = early_pfn_to_nid(PFN_DOWN(start));
 
 			reserve_bootmem_region(start, end, nid);
@@ -2240,10 +2399,357 @@ void __init memblock_free_all(void)
 	free_unused_memmap();
 	reset_all_zones_managed_pages();
 
+	memblock_clear_kho_scratch_only();
 	pages = free_low_memory_core_early();
 	totalram_pages_add(pages);
 }
 
+/* Keep a table to reserve named memory */
+#define RESERVE_MEM_MAX_ENTRIES		8
+#define RESERVE_MEM_NAME_SIZE		16
+struct reserve_mem_table {
+	char			name[RESERVE_MEM_NAME_SIZE];
+	phys_addr_t		start;
+	phys_addr_t		size;
+};
+static struct reserve_mem_table reserved_mem_table[RESERVE_MEM_MAX_ENTRIES];
+static int reserved_mem_count;
+static DEFINE_MUTEX(reserve_mem_lock);
+
+/* Add wildcard region with a lookup name */
+static void __init reserved_mem_add(phys_addr_t start, phys_addr_t size,
+				   const char *name)
+{
+	struct reserve_mem_table *map;
+
+	map = &reserved_mem_table[reserved_mem_count++];
+	map->start = start;
+	map->size = size;
+	strscpy(map->name, name);
+}
+
+static struct reserve_mem_table *reserve_mem_find_by_name_nolock(const char *name)
+{
+	struct reserve_mem_table *map;
+	int i;
+
+	for (i = 0; i < reserved_mem_count; i++) {
+		map = &reserved_mem_table[i];
+		if (!map->size)
+			continue;
+		if (strcmp(name, map->name) == 0)
+			return map;
+	}
+	return NULL;
+}
+
+/**
+ * reserve_mem_find_by_name - Find reserved memory region with a given name
+ * @name: The name that is attached to a reserved memory region
+ * @start: If found, holds the start address
+ * @size: If found, holds the size of the address.
+ *
+ * @start and @size are only updated if @name is found.
+ *
+ * Returns: 1 if found or 0 if not found.
+ */
+int reserve_mem_find_by_name(const char *name, phys_addr_t *start, phys_addr_t *size)
+{
+	struct reserve_mem_table *map;
+
+	guard(mutex)(&reserve_mem_lock);
+	map = reserve_mem_find_by_name_nolock(name);
+	if (!map)
+		return 0;
+
+	*start = map->start;
+	*size = map->size;
+	return 1;
+}
+EXPORT_SYMBOL_GPL(reserve_mem_find_by_name);
+
+/**
+ * reserve_mem_release_by_name - Release reserved memory region with a given name
+ * @name: The name that is attatched to a reserved memory region
+ *
+ * Forcibly release the pages in the reserved memory region so that those memory
+ * can be used as free memory. After released the reserved region size becomes 0.
+ *
+ * Returns: 1 if released or 0 if not found.
+ */
+int reserve_mem_release_by_name(const char *name)
+{
+	char buf[RESERVE_MEM_NAME_SIZE + 12];
+	struct reserve_mem_table *map;
+	void *start, *end;
+
+	guard(mutex)(&reserve_mem_lock);
+	map = reserve_mem_find_by_name_nolock(name);
+	if (!map)
+		return 0;
+
+	start = phys_to_virt(map->start);
+	end = start + map->size - 1;
+	snprintf(buf, sizeof(buf), "reserve_mem:%s", name);
+	free_reserved_area(start, end, 0, buf);
+	map->size = 0;
+
+	return 1;
+}
+
+#ifdef CONFIG_KEXEC_HANDOVER
+#define MEMBLOCK_KHO_FDT "memblock"
+#define MEMBLOCK_KHO_NODE_COMPATIBLE "memblock-v1"
+#define RESERVE_MEM_KHO_NODE_COMPATIBLE "reserve-mem-v1"
+static struct page *kho_fdt;
+
+static int reserve_mem_kho_finalize(struct kho_serialization *ser)
+{
+	int err = 0, i;
+
+	for (i = 0; i < reserved_mem_count; i++) {
+		struct reserve_mem_table *map = &reserved_mem_table[i];
+
+		err |= kho_preserve_phys(map->start, map->size);
+	}
+
+	err |= kho_preserve_folio(page_folio(kho_fdt));
+	err |= kho_add_subtree(ser, MEMBLOCK_KHO_FDT, page_to_virt(kho_fdt));
+
+	return notifier_from_errno(err);
+}
+
+static int reserve_mem_kho_notifier(struct notifier_block *self,
+				    unsigned long cmd, void *v)
+{
+	switch (cmd) {
+	case KEXEC_KHO_FINALIZE:
+		return reserve_mem_kho_finalize((struct kho_serialization *)v);
+	case KEXEC_KHO_ABORT:
+		return NOTIFY_DONE;
+	default:
+		return NOTIFY_BAD;
+	}
+}
+
+static struct notifier_block reserve_mem_kho_nb = {
+	.notifier_call = reserve_mem_kho_notifier,
+};
+
+static int __init prepare_kho_fdt(void)
+{
+	int err = 0, i;
+	void *fdt;
+
+	kho_fdt = alloc_page(GFP_KERNEL);
+	if (!kho_fdt)
+		return -ENOMEM;
+
+	fdt = page_to_virt(kho_fdt);
+
+	err |= fdt_create(fdt, PAGE_SIZE);
+	err |= fdt_finish_reservemap(fdt);
+
+	err |= fdt_begin_node(fdt, "");
+	err |= fdt_property_string(fdt, "compatible", MEMBLOCK_KHO_NODE_COMPATIBLE);
+	for (i = 0; i < reserved_mem_count; i++) {
+		struct reserve_mem_table *map = &reserved_mem_table[i];
+
+		err |= fdt_begin_node(fdt, map->name);
+		err |= fdt_property_string(fdt, "compatible", RESERVE_MEM_KHO_NODE_COMPATIBLE);
+		err |= fdt_property(fdt, "start", &map->start, sizeof(map->start));
+		err |= fdt_property(fdt, "size", &map->size, sizeof(map->size));
+		err |= fdt_end_node(fdt);
+	}
+	err |= fdt_end_node(fdt);
+
+	err |= fdt_finish(fdt);
+
+	if (err) {
+		pr_err("failed to prepare memblock FDT for KHO: %d\n", err);
+		put_page(kho_fdt);
+		kho_fdt = NULL;
+	}
+
+	return err;
+}
+
+static int __init reserve_mem_init(void)
+{
+	int err;
+
+	if (!kho_is_enabled() || !reserved_mem_count)
+		return 0;
+
+	err = prepare_kho_fdt();
+	if (err)
+		return err;
+
+	err = register_kho_notifier(&reserve_mem_kho_nb);
+	if (err) {
+		put_page(kho_fdt);
+		kho_fdt = NULL;
+	}
+
+	return err;
+}
+late_initcall(reserve_mem_init);
+
+static void *__init reserve_mem_kho_retrieve_fdt(void)
+{
+	phys_addr_t fdt_phys;
+	static void *fdt;
+	int err;
+
+	if (fdt)
+		return fdt;
+
+	err = kho_retrieve_subtree(MEMBLOCK_KHO_FDT, &fdt_phys);
+	if (err) {
+		if (err != -ENOENT)
+			pr_warn("failed to retrieve FDT '%s' from KHO: %d\n",
+				MEMBLOCK_KHO_FDT, err);
+		return NULL;
+	}
+
+	fdt = phys_to_virt(fdt_phys);
+
+	err = fdt_node_check_compatible(fdt, 0, MEMBLOCK_KHO_NODE_COMPATIBLE);
+	if (err) {
+		pr_warn("FDT '%s' is incompatible with '%s': %d\n",
+			MEMBLOCK_KHO_FDT, MEMBLOCK_KHO_NODE_COMPATIBLE, err);
+		fdt = NULL;
+	}
+
+	return fdt;
+}
+
+static bool __init reserve_mem_kho_revive(const char *name, phys_addr_t size,
+					  phys_addr_t align)
+{
+	int err, len_start, len_size, offset;
+	const phys_addr_t *p_start, *p_size;
+	const void *fdt;
+
+	fdt = reserve_mem_kho_retrieve_fdt();
+	if (!fdt)
+		return false;
+
+	offset = fdt_subnode_offset(fdt, 0, name);
+	if (offset < 0) {
+		pr_warn("FDT '%s' has no child '%s': %d\n",
+			MEMBLOCK_KHO_FDT, name, offset);
+		return false;
+	}
+	err = fdt_node_check_compatible(fdt, offset, RESERVE_MEM_KHO_NODE_COMPATIBLE);
+	if (err) {
+		pr_warn("Node '%s' is incompatible with '%s': %d\n",
+			name, RESERVE_MEM_KHO_NODE_COMPATIBLE, err);
+		return false;
+	}
+
+	p_start = fdt_getprop(fdt, offset, "start", &len_start);
+	p_size = fdt_getprop(fdt, offset, "size", &len_size);
+	if (!p_start || len_start != sizeof(*p_start) || !p_size ||
+	    len_size != sizeof(*p_size)) {
+		return false;
+	}
+
+	if (*p_start & (align - 1)) {
+		pr_warn("KHO reserve-mem '%s' has wrong alignment (0x%lx, 0x%lx)\n",
+			name, (long)align, (long)*p_start);
+		return false;
+	}
+
+	if (*p_size != size) {
+		pr_warn("KHO reserve-mem '%s' has wrong size (0x%lx != 0x%lx)\n",
+			name, (long)*p_size, (long)size);
+		return false;
+	}
+
+	reserved_mem_add(*p_start, size, name);
+	pr_info("Revived memory reservation '%s' from KHO\n", name);
+
+	return true;
+}
+#else
+static bool __init reserve_mem_kho_revive(const char *name, phys_addr_t size,
+					  phys_addr_t align)
+{
+	return false;
+}
+#endif /* CONFIG_KEXEC_HANDOVER */
+
+/*
+ * Parse reserve_mem=nn:align:name
+ */
+static int __init reserve_mem(char *p)
+{
+	phys_addr_t start, size, align, tmp;
+	char *name;
+	char *oldp;
+	int len;
+
+	if (!p)
+		return -EINVAL;
+
+	/* Check if there's room for more reserved memory */
+	if (reserved_mem_count >= RESERVE_MEM_MAX_ENTRIES)
+		return -EBUSY;
+
+	oldp = p;
+	size = memparse(p, &p);
+	if (!size || p == oldp)
+		return -EINVAL;
+
+	if (*p != ':')
+		return -EINVAL;
+
+	align = memparse(p+1, &p);
+	if (*p != ':')
+		return -EINVAL;
+
+	/*
+	 * memblock_phys_alloc() doesn't like a zero size align,
+	 * but it is OK for this command to have it.
+	 */
+	if (align < SMP_CACHE_BYTES)
+		align = SMP_CACHE_BYTES;
+
+	name = p + 1;
+	len = strlen(name);
+
+	/* name needs to have length but not too big */
+	if (!len || len >= RESERVE_MEM_NAME_SIZE)
+		return -EINVAL;
+
+	/* Make sure that name has text */
+	for (p = name; *p; p++) {
+		if (!isspace(*p))
+			break;
+	}
+	if (!*p)
+		return -EINVAL;
+
+	/* Make sure the name is not already used */
+	if (reserve_mem_find_by_name(name, &start, &tmp))
+		return -EBUSY;
+
+	/* Pick previous allocations up from KHO if available */
+	if (reserve_mem_kho_revive(name, size, align))
+		return 1;
+
+	/* TODO: Allocation must be outside of scratch region */
+	start = memblock_phys_alloc(size, align);
+	if (!start)
+		return -ENOMEM;
+
+	reserved_mem_add(start, size, name);
+
+	return 1;
+}
+__setup("reserve_mem=", reserve_mem);
+
 #if defined(CONFIG_DEBUG_FS) && defined(CONFIG_ARCH_KEEP_MEMBLOCK)
 static const char * const flagname[] = {
 	[ilog2(MEMBLOCK_HOTPLUG)] = "HOTPLUG",
@@ -2251,6 +2757,8 @@ static const char * const flagname[] = {
 	[ilog2(MEMBLOCK_NOMAP)] = "NOMAP",
 	[ilog2(MEMBLOCK_DRIVER_MANAGED)] = "DRV_MNG",
 	[ilog2(MEMBLOCK_RSRV_NOINIT)] = "RSV_NIT",
+	[ilog2(MEMBLOCK_RSRV_KERN)] = "RSV_KERN",
+	[ilog2(MEMBLOCK_KHO_SCRATCH)] = "KHO_SCRATCH",
 };
 
 static int memblock_debug_show(struct seq_file *m, void *private)
@@ -2268,7 +2776,7 @@ static int memblock_debug_show(struct seq_file *m, void *private)
 
 		seq_printf(m, "%4d: ", i);
 		seq_printf(m, "%pa..%pa ", &reg->base, &end);
-		if (nid != MAX_NUMNODES)
+		if (numa_valid_node(nid))
 			seq_printf(m, "%4d ", nid);
 		else
 			seq_printf(m, "%4c ", 'x');