1 files changed, 341 insertions, 122 deletions

diff --git a/mm/memblock.c b/mm/memblock.c
index b3ddfdec7a80..021db49eb7fc 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -17,17 +17,17 @@
 #include <linux/seq_file.h>
 #include <linux/memblock.h>
 #include <linux/mutex.h>
+#include <linux/string_helpers.h>
 
-#ifdef CONFIG_KEXEC_HANDOVER
 #include <linux/libfdt.h>
 #include <linux/kexec_handover.h>
 #include <linux/kho/abi/memblock.h>
-#endif /* CONFIG_KEXEC_HANDOVER */
 
 #include <asm/sections.h>
 #include <linux/io.h>
 
 #include "internal.h"
+#include "mm_init.h"
 
 #define INIT_MEMBLOCK_REGIONS			128
 #define INIT_PHYSMEM_REGIONS			4
@@ -384,26 +384,27 @@ static void __init_memblock memblock_remove_region(struct memblock_type *type, u
  */
 void __init memblock_discard(void)
 {
-	phys_addr_t addr, size;
+	phys_addr_t size;
+	void *addr;
 
 	if (memblock.reserved.regions != memblock_reserved_init_regions) {
-		addr = __pa(memblock.reserved.regions);
+		addr = memblock.reserved.regions;
 		size = PAGE_ALIGN(sizeof(struct memblock_region) *
 				  memblock.reserved.max);
 		if (memblock_reserved_in_slab)
-			kfree(memblock.reserved.regions);
+			kfree(addr);
 		else
-			memblock_free_late(addr, size);
+			memblock_free(addr, size);
 	}
 
 	if (memblock.memory.regions != memblock_memory_init_regions) {
-		addr = __pa(memblock.memory.regions);
+		addr = memblock.memory.regions;
 		size = PAGE_ALIGN(sizeof(struct memblock_region) *
 				  memblock.memory.max);
 		if (memblock_memory_in_slab)
-			kfree(memblock.memory.regions);
+			kfree(addr);
 		else
-			memblock_free_late(addr, size);
+			memblock_free(addr, size);
 	}
 
 	memblock_memory = NULL;
@@ -893,13 +894,81 @@ int __init_memblock memblock_remove(phys_addr_t base, phys_addr_t size)
 	return memblock_remove_range(&memblock.memory, base, size);
 }
 
+static unsigned long __free_reserved_area(phys_addr_t start, phys_addr_t end,
+					  int poison)
+{
+	unsigned long pages = 0, pfn;
+
+	if (deferred_pages_enabled()) {
+		WARN(1, "Cannot free reserved memory because of deferred initialization of the memory map");
+		return 0;
+	}
+
+	for_each_valid_pfn(pfn, PFN_UP(start), PFN_DOWN(end)) {
+		struct page *page = pfn_to_page(pfn);
+		void *direct_map_addr;
+
+		/*
+		 * 'direct_map_addr' might be different from the kernel virtual
+		 * address because some architectures use aliases.
+		 * Going via physical address, pfn_to_page() and page_address()
+		 * ensures that we get a _writeable_ alias for the memset().
+		 */
+		direct_map_addr = page_address(page);
+		/*
+		 * Perform a kasan-unchecked memset() since this memory
+		 * has not been initialized.
+		 */
+		direct_map_addr = kasan_reset_tag(direct_map_addr);
+		if ((unsigned int)poison <= 0xFF)
+			memset(direct_map_addr, poison, PAGE_SIZE);
+
+		free_reserved_page(page);
+		pages++;
+	}
+	return pages;
+}
+
+unsigned long free_reserved_area(void *start, void *end, int poison, const char *s)
+{
+	phys_addr_t start_pa, end_pa;
+	unsigned long pages;
+
+	/*
+	 * end is the first address past the region and it may be beyond what
+	 * __pa() or __pa_symbol() can handle.
+	 * Use the address included in the range for the conversion and add back
+	 * 1 afterwards.
+	 */
+	if (__is_kernel((unsigned long)start)) {
+		start_pa = __pa_symbol(start);
+		end_pa = __pa_symbol(end - 1) + 1;
+	} else {
+		start_pa = __pa(start);
+		end_pa = __pa(end - 1) + 1;
+	}
+
+	if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK)) {
+		if (start_pa < end_pa)
+			memblock_remove_range(&memblock.reserved,
+					      start_pa, end_pa - start_pa);
+	}
+
+	pages = __free_reserved_area(start_pa, end_pa, poison);
+	if (pages && s)
+		pr_info("Freeing %s memory: %ldK\n", s, K(pages));
+
+	return pages;
+}
+
 /**
  * memblock_free - free boot memory allocation
  * @ptr: starting address of the  boot memory allocation
  * @size: size of the boot memory block in bytes
  *
  * Free boot memory block previously allocated by memblock_alloc_xx() API.
- * The freeing memory will not be released to the buddy allocator.
+ * If called after the buddy allocator is available, the memory is released to
+ * the buddy allocator.
  */
 void __init_memblock memblock_free(void *ptr, size_t size)
 {
@@ -913,17 +982,26 @@ void __init_memblock memblock_free(void *ptr, size_t size)
  * @size: size of the boot memory block in bytes
  *
  * Free boot memory block previously allocated by memblock_phys_alloc_xx() API.
- * The freeing memory will not be released to the buddy allocator.
+ * If called after the buddy allocator is available, the memory is released to
+ * the buddy allocator.
  */
 int __init_memblock memblock_phys_free(phys_addr_t base, phys_addr_t size)
 {
 	phys_addr_t end = base + size - 1;
+	int ret = 0;
 
 	memblock_dbg("%s: [%pa-%pa] %pS\n", __func__,
 		     &base, &end, (void *)_RET_IP_);
 
 	kmemleak_free_part_phys(base, size);
-	return memblock_remove_range(&memblock.reserved, base, size);
+
+	if (!slab_is_available() || IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK))
+		ret = memblock_remove_range(&memblock.reserved, base, size);
+
+	if (slab_is_available())
+		__free_reserved_area(base, base + size, -1);
+
+	return ret;
 }
 
 int __init_memblock __memblock_reserve(phys_addr_t base, phys_addr_t size,
@@ -949,40 +1027,6 @@ 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
@@ -1116,6 +1160,21 @@ int __init_memblock memblock_reserved_mark_noinit(phys_addr_t base, phys_addr_t
 }
 
 /**
+ * memblock_reserved_mark_kern - Mark a reserved memory region with flag
+ * MEMBLOCK_RSRV_KERN
+ *
+ * @base: the base phys addr of the region
+ * @size: the size of the region
+ *
+ * Return: 0 on success, -errno on failure.
+ */
+int __init_memblock memblock_reserved_mark_kern(phys_addr_t base, phys_addr_t size)
+{
+	return memblock_setclr_flag(&memblock.reserved, base, size, 1,
+				    MEMBLOCK_RSRV_KERN);
+}
+
+/**
  * 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
@@ -1446,6 +1505,32 @@ int __init_memblock memblock_set_node(phys_addr_t base, phys_addr_t size,
 	return 0;
 }
 
+static void memblock_prep_allocation(phys_addr_t start, phys_addr_t size,
+				     bool kmemleak_trace)
+{
+	/*
+	 * Skip kmemleak for those places like kasan_init() and
+	 * early_pgtable_alloc() due to high volume.
+	 */
+	if (kmemleak_trace)
+		/*
+		 * Memblock allocated blocks are never reported as
+		 * leaks. This is because many of these blocks are
+		 * only referred via the physical address which is
+		 * not looked up by kmemleak.
+		 */
+		kmemleak_alloc_phys(start, size, 0);
+
+	/*
+	 * Some Virtual Machine platforms, such as Intel TDX or AMD SEV-SNP,
+	 * require memory to be accepted before it can be used by the
+	 * guest.
+	 *
+	 * Accept the memory of the allocated buffer.
+	 */
+	accept_memory(start, size);
+}
+
 /**
  * memblock_alloc_range_nid - allocate boot memory block
  * @size: size of memory block to be allocated in bytes
@@ -1520,28 +1605,7 @@ again:
 	return 0;
 
 done:
-	/*
-	 * Skip kmemleak for those places like kasan_init() and
-	 * early_pgtable_alloc() due to high volume.
-	 */
-	if (end != MEMBLOCK_ALLOC_NOLEAKTRACE)
-		/*
-		 * Memblock allocated blocks are never reported as
-		 * leaks. This is because many of these blocks are
-		 * only referred via the physical address which is
-		 * not looked up by kmemleak.
-		 */
-		kmemleak_alloc_phys(found, size, 0);
-
-	/*
-	 * Some Virtual Machine platforms, such as Intel TDX or AMD SEV-SNP,
-	 * require memory to be accepted before it can be used by the
-	 * guest.
-	 *
-	 * Accept the memory of the allocated buffer.
-	 */
-	accept_memory(found, size);
-
+	memblock_prep_allocation(found, size, end != MEMBLOCK_ALLOC_NOLEAKTRACE);
 	return found;
 }
 
@@ -1697,6 +1761,77 @@ void * __init memblock_alloc_try_nid_raw(
 }
 
 /**
+ * memblock_alloc_hugetlb - allocate boot memory for HugeTLB pages
+ * @size:      size of the memory to be allocated in bytes
+ * @nid:       nid of the free memory to find, %NUMA_NO_NODE for any node
+ * @exact_nid: only allocate from the specified nid. If %false, the specified
+ *             nid is tried first, and then all nodes are tried as fallback.
+ *
+ * HugeTLB pages are always aligned by their size, so the alignment matches
+ * @size. Since the memory is for userspace, mirrored memory is not used. The
+ * memory is not zeroed. Does not panic if request cannot be satisfied.
+ *
+ * Return:
+ * Virtual address of allocated memory block on success, %NULL on failure.
+ */
+void * __init memblock_alloc_hugetlb(phys_addr_t size, int nid, bool exact_nid)
+{
+	enum memblock_flags flags = choose_memblock_flags();
+	phys_addr_t addr, start = 0, end = MEMBLOCK_ALLOC_ACCESSIBLE;
+
+	memblock_dbg("%s: %llu bytes, nid=%d, exact_nid=%d %pS\n", __func__,
+		     (u64)size, nid, exact_nid, (void *)_RET_IP_);
+
+	/* Don't waste mirrored memory on HugeTLB pages. */
+	flags &= ~MEMBLOCK_MIRROR;
+retry:
+	/* HugeTLB pages are always aligned by their size. */
+	addr = memblock_find_in_range_node(size, size, start, end, nid, flags);
+	if (addr)
+		goto found;
+
+	/* Try all nodes if allowed. */
+	if (numa_valid_node(nid) && !exact_nid) {
+		nid = NUMA_NO_NODE;
+		/*
+		 * If a previous candidate overlapped with KHO scratch, it would
+		 * update start or end. Now that the search is opening to all
+		 * nodes, reset them.
+		 */
+		start = 0;
+		end = MEMBLOCK_ALLOC_ACCESSIBLE;
+
+		goto retry;
+	}
+
+	/* Found nothing... :-( */
+	return NULL;
+
+found:
+	/*
+	 * HugeTLB pages can be preserved with KHO and no preserved memory can
+	 * be in scratch. So retry if found address overlaps with scratch.
+	 *
+	 * Scratch areas are normally not very large, so this shouldn't take too
+	 * many retries.
+	 */
+	if (kho_scratch_overlap(addr, size)) {
+		if (memblock_bottom_up())
+			start = addr + size;
+		else
+			end = addr;
+
+		goto retry;
+	}
+
+	if (__memblock_reserve(addr, size, nid, MEMBLOCK_RSRV_KERN | MEMBLOCK_RSRV_HUGETLB))
+		return NULL;
+
+	memblock_prep_allocation(addr, size, true);
+	return phys_to_virt(addr);
+}
+
+/**
  * memblock_alloc_try_nid - allocate boot memory block
  * @size: size of memory block to be allocated in bytes
  * @align: alignment of the region and block's size
@@ -1751,32 +1886,6 @@ void *__init __memblock_alloc_or_panic(phys_addr_t size, phys_addr_t align,
 	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
- *
- * This is only useful when the memblock allocator has already been torn
- * down, but we are still initializing the system.  Pages are released directly
- * to the buddy allocator.
- */
-void __init memblock_free_late(phys_addr_t base, phys_addr_t size)
-{
-	phys_addr_t cursor, end;
-
-	end = base + size - 1;
-	memblock_dbg("%s: [%pa-%pa] %pS\n",
-		     __func__, &base, &end, (void *)_RET_IP_);
-	kmemleak_free_part_phys(base, size);
-	cursor = PFN_UP(base);
-	end = PFN_DOWN(base + size);
-
-	for (; cursor < end; cursor++) {
-		memblock_free_pages(cursor, 0);
-		totalram_pages_inc();
-	}
-}
-
 /*
  * Remaining API functions
  */
@@ -1791,6 +1900,28 @@ phys_addr_t __init_memblock memblock_reserved_size(void)
 	return memblock.reserved.total_size;
 }
 
+phys_addr_t __init_memblock memblock_reserved_hugetlb_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_HUGETLB)
+				total += size;
+	}
+
+	return total;
+}
+
 phys_addr_t __init_memblock memblock_reserved_kern_size(phys_addr_t limit, int nid)
 {
 	struct memblock_region *r;
@@ -2190,10 +2321,8 @@ static void __init free_unused_memmap(void)
 	}
 
 #ifdef CONFIG_SPARSEMEM
-	if (!IS_ALIGNED(prev_end, PAGES_PER_SECTION)) {
-		prev_end = pageblock_align(end);
+	if (!IS_ALIGNED(prev_end, PAGES_PER_SECTION))
 		free_memmap(prev_end, ALIGN(prev_end, PAGES_PER_SECTION));
-	}
 #endif
 }
 
@@ -2240,6 +2369,31 @@ static unsigned long __init __free_memory_core(phys_addr_t start,
 	return end_pfn - start_pfn;
 }
 
+/*
+ * Initialised pages do not have PageReserved set. This function is called
+ * for each reserved range and marks the pages PageReserved.
+ * When deferred initialization of struct pages is enabled it also ensures
+ * that struct pages are properly initialised.
+ */
+static void __init memmap_init_reserved_range(phys_addr_t start,
+					      phys_addr_t end, int nid)
+{
+	unsigned long pfn;
+
+	for_each_valid_pfn(pfn, PFN_DOWN(start), PFN_UP(end)) {
+		struct page *page = pfn_to_page(pfn);
+
+		init_deferred_page(pfn, nid);
+
+		/*
+		 * no need for atomic set_bit because the struct
+		 * page is not visible yet so nobody should
+		 * access it yet.
+		 */
+		__SetPageReserved(page);
+	}
+}
+
 static void __init memmap_init_reserved_pages(void)
 {
 	struct memblock_region *region;
@@ -2259,7 +2413,7 @@ repeat:
 		end = start + region->size;
 
 		if (memblock_is_nomap(region))
-			reserve_bootmem_region(start, end, nid);
+			memmap_init_reserved_range(start, end, nid);
 
 		memblock_set_node(start, region->size, &memblock.reserved, nid);
 	}
@@ -2284,7 +2438,7 @@ repeat:
 			if (!numa_valid_node(nid))
 				nid = early_pfn_to_nid(PFN_DOWN(start));
 
-			reserve_bootmem_region(start, end, nid);
+			memmap_init_reserved_range(start, end, nid);
 		}
 	}
 }
@@ -2434,7 +2588,7 @@ int reserve_mem_release_by_name(const char *name)
 		return 0;
 
 	start = phys_to_virt(map->start);
-	end = start + map->size - 1;
+	end = start + map->size;
 	snprintf(buf, sizeof(buf), "reserve_mem:%s", name);
 	free_reserved_area(start, end, 0, buf);
 	map->size = 0;
@@ -2442,6 +2596,18 @@ int reserve_mem_release_by_name(const char *name)
 	return 1;
 }
 
+#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;
+}
+#endif
+
 #ifdef CONFIG_KEXEC_HANDOVER
 
 static int __init reserved_mem_preserve(void)
@@ -2510,7 +2676,7 @@ static int __init prepare_kho_fdt(void)
 	if (err)
 		goto err_unpreserve_fdt;
 
-	err = kho_add_subtree(MEMBLOCK_KHO_FDT, fdt);
+	err = kho_add_subtree(MEMBLOCK_KHO_FDT, fdt, fdt_totalsize(fdt));
 	if (err)
 		goto err_unpreserve_fdt;
 
@@ -2555,7 +2721,7 @@ static void *__init reserve_mem_kho_retrieve_fdt(void)
 	if (fdt)
 		return fdt;
 
-	err = kho_retrieve_subtree(MEMBLOCK_KHO_FDT, &fdt_phys);
+	err = kho_retrieve_subtree(MEMBLOCK_KHO_FDT, &fdt_phys, NULL);
 	if (err) {
 		if (err != -ENOENT)
 			pr_warn("failed to retrieve FDT '%s' from KHO: %d\n",
@@ -2642,23 +2808,25 @@ static int __init reserve_mem(char *p)
 	int len;
 
 	if (!p)
-		return -EINVAL;
+		goto err_param;
 
 	/* Check if there's room for more reserved memory */
-	if (reserved_mem_count >= RESERVE_MEM_MAX_ENTRIES)
+	if (reserved_mem_count >= RESERVE_MEM_MAX_ENTRIES) {
+		pr_err("reserve_mem: no more room for reserved memory\n");
 		return -EBUSY;
+	}
 
 	oldp = p;
 	size = memparse(p, &p);
 	if (!size || p == oldp)
-		return -EINVAL;
+		goto err_param;
 
 	if (*p != ':')
-		return -EINVAL;
+		goto err_param;
 
 	align = memparse(p+1, &p);
 	if (*p != ':')
-		return -EINVAL;
+		goto err_param;
 
 	/*
 	 * memblock_phys_alloc() doesn't like a zero size align,
@@ -2672,7 +2840,7 @@ static int __init reserve_mem(char *p)
 
 	/* name needs to have length but not too big */
 	if (!len || len >= RESERVE_MEM_NAME_SIZE)
-		return -EINVAL;
+		goto err_param;
 
 	/* Make sure that name has text */
 	for (p = name; *p; p++) {
@@ -2680,11 +2848,13 @@ static int __init reserve_mem(char *p)
 			break;
 	}
 	if (!*p)
-		return -EINVAL;
+		goto err_param;
 
 	/* Make sure the name is not already used */
-	if (reserve_mem_find_by_name(name, &start, &tmp))
+	if (reserve_mem_find_by_name(name, &start, &tmp)) {
+		pr_err("reserve_mem: name \"%s\" was already used\n", name);
 		return -EBUSY;
+	}
 
 	/* Pick previous allocations up from KHO if available */
 	if (reserve_mem_kho_revive(name, size, align))
@@ -2692,16 +2862,22 @@ static int __init reserve_mem(char *p)
 
 	/* TODO: Allocation must be outside of scratch region */
 	start = memblock_phys_alloc(size, align);
-	if (!start)
+	if (!start) {
+		pr_err("reserve_mem: memblock allocation failed\n");
 		return -ENOMEM;
+	}
 
 	reserved_mem_add(start, size, name);
 
 	return 1;
+err_param:
+	pr_err("reserve_mem: empty or malformed parameter\n");
+	return -EINVAL;
 }
 __setup("reserve_mem=", reserve_mem);
 
-#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_ARCH_KEEP_MEMBLOCK)
+#ifdef CONFIG_DEBUG_FS
+#ifdef CONFIG_ARCH_KEEP_MEMBLOCK
 static const char * const flagname[] = {
 	[ilog2(MEMBLOCK_HOTPLUG)] = "HOTPLUG",
 	[ilog2(MEMBLOCK_MIRROR)] = "MIRROR",
@@ -2732,14 +2908,18 @@ static int memblock_debug_show(struct seq_file *m, void *private)
 		else
 			seq_printf(m, "%4c ", 'x');
 		if (reg->flags) {
-			for (j = 0; j < count; j++) {
-				if (reg->flags & (1U << j)) {
-					seq_printf(m, "%s\n", flagname[j]);
-					break;
-				}
+			unsigned int flags = reg->flags;
+			bool first = true;
+
+			for (j = 0; flags; j++, flags >>= 1) {
+				if (!(flags & 1))
+					continue;
+				if (!first)
+					seq_putc(m, '|');
+				seq_puts(m, j < count ? flagname[j] : "UNKNOWN");
+				first = false;
 			}
-			if (j == count)
-				seq_printf(m, "%s\n", "UNKNOWN");
+			seq_putc(m, '\n');
 		} else {
 			seq_printf(m, "%s\n", "NONE");
 		}
@@ -2748,10 +2928,8 @@ static int memblock_debug_show(struct seq_file *m, void *private)
 }
 DEFINE_SHOW_ATTRIBUTE(memblock_debug);
 
-static int __init memblock_init_debugfs(void)
+static inline void memblock_debugfs_expose_arrays(struct dentry *root)
 {
-	struct dentry *root = debugfs_create_dir("memblock", NULL);
-
 	debugfs_create_file("memory", 0444, root,
 			    &memblock.memory, &memblock_debug_fops);
 	debugfs_create_file("reserved", 0444, root,
@@ -2760,7 +2938,48 @@ static int __init memblock_init_debugfs(void)
 	debugfs_create_file("physmem", 0444, root, &physmem,
 			    &memblock_debug_fops);
 #endif
+}
+
+#else
+
+static inline void memblock_debugfs_expose_arrays(struct dentry *root) { }
+
+#endif /* CONFIG_ARCH_KEEP_MEMBLOCK */
+
+static int memblock_reserve_mem_show(struct seq_file *m, void *private)
+{
+	struct reserve_mem_table *map;
+	char txtsz[16];
+
+	guard(mutex)(&reserve_mem_lock);
+	for (int i = 0; i < reserved_mem_count; i++) {
+		map = &reserved_mem_table[i];
+		if (!map->size)
+			continue;
+
+		memset(txtsz, 0, sizeof(txtsz));
+		string_get_size(map->size, 1, STRING_UNITS_2, txtsz, sizeof(txtsz));
+		seq_printf(m, "%s\t\t(%s)\n", map->name, txtsz);
+	}
+
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(memblock_reserve_mem);
+
+static int __init memblock_init_debugfs(void)
+{
+	struct dentry *root;
+
+	if (!IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK) && !reserved_mem_count)
+		return 0;
+
+	root = debugfs_create_dir("memblock", NULL);
+
+	if (reserved_mem_count)
+		debugfs_create_file("reserve_mem_param", 0444, root, NULL,
+				    &memblock_reserve_mem_fops);
 
+	memblock_debugfs_expose_arrays(root);
 	return 0;
 }
 __initcall(memblock_init_debugfs);