memblock: updates for 7.0-rc1

* improve debugability of reserve_mem kernel parameter handling with print
   outs in case of a failure and debugfs info showing what was actually
   reserved
 * Make memblock_free_late() and free_reserved_area() use the same core
   logic for freeing the memory to buddy and ensure it takes care of
   updating memblock arrays when ARCH_KEEP_MEMBLOCK is enabled.
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Merge tag 'memblock-v7.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock

Pull memblock updates from Mike Rapoport:

 - improve debuggability of reserve_mem kernel parameter handling with
   print outs in case of a failure and debugfs info showing what was
   actually reserved

 - Make memblock_free_late() and free_reserved_area() use the same core
   logic for freeing the memory to buddy and ensure it takes care of
   updating memblock arrays when ARCH_KEEP_MEMBLOCK is enabled.

* tag 'memblock-v7.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock:
  x86/alternative: delay freeing of smp_locks section
  memblock: warn when freeing reserved memory before memory map is initialized
  memblock, treewide: make memblock_free() handle late freeing
  memblock: make free_reserved_area() update memblock if ARCH_KEEP_MEMBLOCK=y
  memblock: extract page freeing from free_reserved_area() into a helper
  memblock: make free_reserved_area() more robust
  mm: move free_reserved_area() to mm/memblock.c
  powerpc: opal-core: pair alloc_pages_exact() with free_pages_exact()
  powerpc: fadump: pair alloc_pages_exact() with free_pages_exact()
  memblock: reserve_mem: fix end caclulation in reserve_mem_release_by_name()
  memblock: move reserve_bootmem_range() to memblock.c and make it static
  memblock: Add reserve_mem debugfs info
  memblock: Print out errors on reserve_mem parser

arch/arm64/mm/init.c

@@ -397,9 +397,6 @@ void free_initmem(void)
 	WARN_ON(!IS_ALIGNED((unsigned long)lm_init_begin, PAGE_SIZE));
 	WARN_ON(!IS_ALIGNED((unsigned long)lm_init_end, PAGE_SIZE));
 
-	/* Delete __init region from memblock.reserved. */
-	memblock_free(lm_init_begin, lm_init_end - lm_init_begin);
-
 	free_reserved_area(lm_init_begin, lm_init_end,
 			   POISON_FREE_INITMEM, "unused kernel");
 	/*

arch/powerpc/kernel/fadump.c

@@ -775,24 +775,12 @@ void __init fadump_update_elfcore_header(char *bufp)
 
 static void *__init fadump_alloc_buffer(unsigned long size)
 {
-	unsigned long count, i;
-	struct page *page;
-	void *vaddr;
-
-	vaddr = alloc_pages_exact(size, GFP_KERNEL | __GFP_ZERO);
-	if (!vaddr)
-		return NULL;
-
-	count = PAGE_ALIGN(size) / PAGE_SIZE;
-	page = virt_to_page(vaddr);
-	for (i = 0; i < count; i++)
-		mark_page_reserved(page + i);
-	return vaddr;
+	return  alloc_pages_exact(size, GFP_KERNEL | __GFP_ZERO);
 }
 
 static void fadump_free_buffer(unsigned long vaddr, unsigned long size)
 {
-	free_reserved_area((void *)vaddr, (void *)(vaddr + size), -1, NULL);
+	free_pages_exact((void *)vaddr, size);
 }
 
 s32 __init fadump_setup_cpu_notes_buf(u32 num_cpus)

arch/powerpc/platforms/powernv/opal-core.c

@@ -303,7 +303,6 @@ static int __init create_opalcore(void)
 	struct device_node *dn;
 	struct opalcore *new;
 	loff_t opalcore_off;
-	struct page *page;
 	Elf64_Phdr *phdr;
 	Elf64_Ehdr *elf;
 	int i, ret;
@@ -328,11 +327,6 @@ static int __init create_opalcore(void)
 		oc_conf->opalcorebuf_sz = 0;
 		return -ENOMEM;
 	}
-	count = oc_conf->opalcorebuf_sz / PAGE_SIZE;
-	page = virt_to_page(oc_conf->opalcorebuf);
-	for (i = 0; i < count; i++)
-		mark_page_reserved(page + i);
-
 	pr_debug("opalcorebuf = 0x%llx\n", (u64)oc_conf->opalcorebuf);
 
 	/* Read OPAL related device-tree entries */
@@ -437,10 +431,7 @@ static void opalcore_cleanup(void)
 
 	/* free the buffer used for setting up OPAL core */
 	if (oc_conf->opalcorebuf) {
-		void *end = (void *)((u64)oc_conf->opalcorebuf +
-				     oc_conf->opalcorebuf_sz);
-
-		free_reserved_area(oc_conf->opalcorebuf, end, -1, NULL);
+		free_pages_exact(oc_conf->opalcorebuf, oc_conf->opalcorebuf_sz);
 		oc_conf->opalcorebuf = NULL;
 		oc_conf->opalcorebuf_sz = 0;
 	}

arch/sparc/kernel/mdesc.c

@@ -183,14 +183,12 @@ static struct mdesc_handle * __init mdesc_memblock_alloc(unsigned int mdesc_size
 static void __init mdesc_memblock_free(struct mdesc_handle *hp)
 {
 	unsigned int alloc_size;
-	unsigned long start;
 
 	BUG_ON(refcount_read(&hp->refcnt) != 0);
 	BUG_ON(!list_empty(&hp->list));
 
 	alloc_size = PAGE_ALIGN(hp->handle_size);
-	start = __pa(hp);
-	memblock_free_late(start, alloc_size);
+	memblock_free(hp, alloc_size);
 }
 
 static struct mdesc_mem_ops memblock_mdesc_ops = {

arch/x86/kernel/alternative.c

@@ -2448,12 +2448,6 @@ void __init alternative_instructions(void)
 					    __smp_locks, __smp_locks_end,
 					    _text, _etext);
 	}
-
-	if (!uniproc_patched || num_possible_cpus() == 1) {
-		free_init_pages("SMP alternatives",
-				(unsigned long)__smp_locks,
-				(unsigned long)__smp_locks_end);
-	}
 #endif
 
 	restart_nmi();
@@ -2462,6 +2456,24 @@ void __init alternative_instructions(void)
 	alt_reloc_selftest();
 }
 
+#ifdef CONFIG_SMP
+/*
+ * With CONFIG_DEFERRED_STRUCT_PAGE_INIT enabled we can free_init_pages() only
+ * after the deferred initialization of the memory map is complete.
+ */
+static int __init free_smp_locks(void)
+{
+	if (!uniproc_patched || num_possible_cpus() == 1) {
+		free_init_pages("SMP alternatives",
+				(unsigned long)__smp_locks,
+				(unsigned long)__smp_locks_end);
+	}
+
+	return 0;
+}
+arch_initcall(free_smp_locks);
+#endif
+
 /**
  * text_poke_early - Update instructions on a live kernel at boot time
  * @addr: address to modify

arch/x86/kernel/setup.c

@@ -426,7 +426,7 @@ int __init ima_free_kexec_buffer(void)
 	if (!ima_kexec_buffer_size)
 		return -ENOENT;
 
-	memblock_free_late(ima_kexec_buffer_phys,
+	memblock_phys_free(ima_kexec_buffer_phys,
 			   ima_kexec_buffer_size);
 
 	ima_kexec_buffer_phys = 0;

arch/x86/platform/efi/memmap.c

@@ -34,10 +34,7 @@ static
 void __init __efi_memmap_free(u64 phys, unsigned long size, unsigned long flags)
 {
 	if (flags & EFI_MEMMAP_MEMBLOCK) {
-		if (slab_is_available())
-			memblock_free_late(phys, size);
-		else
-			memblock_phys_free(phys, size);
+		memblock_phys_free(phys, size);
 	} else if (flags & EFI_MEMMAP_SLAB) {
 		struct page *p = pfn_to_page(PHYS_PFN(phys));
 		unsigned int order = get_order(size);

arch/x86/platform/efi/quirks.c

@@ -372,7 +372,7 @@ void __init efi_reserve_boot_services(void)
 		 * doesn't make sense as far as the firmware is
 		 * concerned, but it does provide us with a way to tag
 		 * those regions that must not be paired with
-		 * memblock_free_late().
+		 * memblock_phys_free().
 		 */
 		md->attribute |= EFI_MEMORY_RUNTIME;
 	}

drivers/firmware/efi/apple-properties.c

@@ -226,7 +226,7 @@ static int __init map_properties(void)
 		 */
 		data->len = 0;
 		memunmap(data);
-		memblock_free_late(pa_data + sizeof(*data), data_len);
+		memblock_phys_free(pa_data + sizeof(*data), data_len);
 
 		return ret;
 	}

drivers/of/kexec.c

@@ -175,7 +175,7 @@ int __init ima_free_kexec_buffer(void)
 	if (ret)
 		return ret;
 
-	memblock_free_late(addr, size);
+	memblock_phys_free(addr, size);
 	return 0;
 }
 #endif

include/linux/bootmem_info.h

@@ -44,10 +44,6 @@ static inline void free_bootmem_page(struct page *page)
 {
 	enum bootmem_type type = bootmem_type(page);
 
-	/*
-	 * The reserve_bootmem_region sets the reserved flag on bootmem
-	 * pages.
-	 */
 	VM_BUG_ON_PAGE(page_ref_count(page) != 2, page);
 
 	if (type == SECTION_INFO || type == MIX_SECTION_INFO)

include/linux/memblock.h

@@ -173,8 +173,6 @@ void __next_mem_range_rev(u64 *idx, int nid, enum memblock_flags flags,
 			  struct memblock_type *type_b, phys_addr_t *out_start,
 			  phys_addr_t *out_end, int *out_nid);
 
-void memblock_free_late(phys_addr_t base, phys_addr_t size);
-
 #ifdef CONFIG_HAVE_MEMBLOCK_PHYS_MAP
 static inline void __next_physmem_range(u64 *idx, struct memblock_type *type,
 					phys_addr_t *out_start,

include/linux/mm.h

@@ -3928,9 +3928,6 @@ extern unsigned long free_reserved_area(void *start, void *end,
 
 extern void adjust_managed_page_count(struct page *page, long count);
 
-extern void reserve_bootmem_region(phys_addr_t start,
-				   phys_addr_t end, int nid);
-
 /* Free the reserved page into the buddy system, so it gets managed. */
 void free_reserved_page(struct page *page);
 

init/initramfs.c

@@ -652,13 +652,6 @@ void __init reserve_initrd_mem(void)
 
 void __weak __init free_initrd_mem(unsigned long start, unsigned long end)
 {
-#ifdef CONFIG_ARCH_KEEP_MEMBLOCK
-	unsigned long aligned_start = ALIGN_DOWN(start, PAGE_SIZE);
-	unsigned long aligned_end = ALIGN(end, PAGE_SIZE);
-
-	memblock_free((void *)aligned_start, aligned_end - aligned_start);
-#endif
-
 	free_reserved_area((void *)start, (void *)end, POISON_FREE_INITMEM,
 			"initrd");
 }

kernel/dma/swiotlb.c

@@ -547,10 +547,10 @@ void __init swiotlb_exit(void)
 		free_pages(tbl_vaddr, get_order(tbl_size));
 		free_pages((unsigned long)mem->slots, get_order(slots_size));
 	} else {
-		memblock_free_late(__pa(mem->areas),
+		memblock_free(mem->areas,
 			array_size(sizeof(*mem->areas), mem->nareas));
-		memblock_free_late(mem->start, tbl_size);
-		memblock_free_late(__pa(mem->slots), slots_size);
+		memblock_phys_free(mem->start, tbl_size);
+		memblock_free(mem->slots, slots_size);
 	}
 
 	memset(mem, 0, sizeof(*mem));

lib/bootconfig.c

@@ -66,7 +66,7 @@ static inline void __init xbc_free_mem(void *addr, size_t size, bool early)
 	if (early)
 		memblock_free(addr, size);
 	else if (addr)
-		memblock_free_late(__pa(addr), size);
+		memblock_free(addr, size);
 }
 
 #else /* !__KERNEL__ */

mm/internal.h

@@ -1322,7 +1322,17 @@ static inline void vunmap_range_noflush(unsigned long start, unsigned long end)
 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
 DECLARE_STATIC_KEY_TRUE(deferred_pages);
 
+static inline bool deferred_pages_enabled(void)
+{
+	return static_branch_unlikely(&deferred_pages);
+}
+
 bool __init deferred_grow_zone(struct zone *zone, unsigned int order);
+#else
+static inline bool deferred_pages_enabled(void)
+{
+	return false;
+}
 #endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */
 
 void init_deferred_page(unsigned long pfn, int nid);

mm/kfence/core.c

@@ -736,10 +736,10 @@ static bool __init kfence_init_pool_early(void)
 	 * fails for the first page, and therefore expect addr==__kfence_pool in
 	 * most failure cases.
 	 */
-	memblock_free_late(__pa(addr), KFENCE_POOL_SIZE - (addr - (unsigned long)__kfence_pool));
+	memblock_free((void *)addr, KFENCE_POOL_SIZE - (addr - (unsigned long)__kfence_pool));
 	__kfence_pool = NULL;
 
-	memblock_free_late(__pa(kfence_metadata_init), KFENCE_METADATA_SIZE);
+	memblock_free(kfence_metadata_init, KFENCE_METADATA_SIZE);
 	kfence_metadata_init = NULL;
 
 	return false;

mm/memblock.c

@@ -17,6 +17,7 @@
 #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>
@@ -384,26 +385,27 @@ 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 +895,81 @@ 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 +983,24 @@ 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;
 
 	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);
+	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,
@@ -973,7 +1050,7 @@ __init void memmap_init_kho_scratch_pages(void)
 	/*
 	 * Initialize struct pages for free scratch memory.
 	 * The struct pages for reserved scratch memory will be set up in
-	 * reserve_bootmem_region()
+	 * memmap_init_reserved_pages()
 	 */
 	__for_each_mem_range(i, &memblock.memory, NULL, NUMA_NO_NODE,
 			     MEMBLOCK_KHO_SCRATCH, &start, &end, &nid) {
@@ -1766,32 +1843,6 @@ 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
  */
@@ -2255,6 +2306,31 @@ 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;
@@ -2274,7 +2350,7 @@ static void __init memmap_init_reserved_pages(void)
 		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);
 	}
@@ -2299,7 +2375,7 @@ static void __init memmap_init_reserved_pages(void)
 			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);
 		}
 	}
 }
@@ -2449,7 +2525,7 @@ 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;
@@ -2657,23 +2733,25 @@ 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,
@@ -2687,7 +2765,7 @@ 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++) {
@@ -2695,11 +2773,13 @@ 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))
@@ -2707,16 +2787,22 @@ 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",
@@ -2763,10 +2849,8 @@ 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,
@@ -2775,7 +2859,48 @@ 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);

mm/mm_init.c

@@ -783,31 +783,6 @@ void __meminit init_deferred_page(unsigned long pfn, int nid)
 	__init_deferred_page(pfn, nid);
 }
 
-/*
- * Initialised pages do not have PageReserved set. This function is
- * called for each range allocated by the bootmem allocator and
- * marks the pages PageReserved. The remaining valid pages are later
- * sent to the buddy page allocator.
- */
-void __meminit reserve_bootmem_region(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);
-	}
-}
-
 /* If zone is ZONE_MOVABLE but memory is mirrored, it is an overlapped init */
 static bool __meminit
 overlap_memmap_init(unsigned long zone, unsigned long *pfn)

mm/page_alloc.c

@@ -297,11 +297,6 @@ int page_group_by_mobility_disabled __read_mostly;
  */
 DEFINE_STATIC_KEY_TRUE(deferred_pages);
 
-static inline bool deferred_pages_enabled(void)
-{
-	return static_branch_unlikely(&deferred_pages);
-}
-
 /*
  * deferred_grow_zone() is __init, but it is called from
  * get_page_from_freelist() during early boot until deferred_pages permanently
@@ -314,11 +309,6 @@ _deferred_grow_zone(struct zone *zone, unsigned int order)
 	return deferred_grow_zone(zone, order);
 }
 #else
-static inline bool deferred_pages_enabled(void)
-{
-	return false;
-}
-
 static inline bool _deferred_grow_zone(struct zone *zone, unsigned int order)
 {
 	return false;
@@ -6211,42 +6201,6 @@ void adjust_managed_page_count(struct page *page, long count)
 }
 EXPORT_SYMBOL(adjust_managed_page_count);
 
-unsigned long free_reserved_area(void *start, void *end, int poison, const char *s)
-{
-	void *pos;
-	unsigned long pages = 0;
-
-	start = (void *)PAGE_ALIGN((unsigned long)start);
-	end = (void *)((unsigned long)end & PAGE_MASK);
-	for (pos = start; pos < end; pos += PAGE_SIZE, pages++) {
-		struct page *page = virt_to_page(pos);
-		void *direct_map_addr;
-
-		/*
-		 * 'direct_map_addr' might be different from 'pos'
-		 * because some architectures' virt_to_page()
-		 * work with aliases.  Getting the direct map
-		 * 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);
-	}
-
-	if (pages && s)
-		pr_info("Freeing %s memory: %ldK\n", s, K(pages));
-
-	return pages;
-}
-
 void free_reserved_page(struct page *page)
 {
 	clear_page_tag_ref(page);

tools/include/linux/mm.h

@@ -17,6 +17,7 @@
 
 #define __va(x) ((void *)((unsigned long)(x)))
 #define __pa(x) ((unsigned long)(x))
+#define __pa_symbol(x) ((unsigned long)(x))
 
 #define pfn_to_page(pfn) ((void *)((pfn) * PAGE_SIZE))
 
@@ -32,8 +33,6 @@ static inline phys_addr_t virt_to_phys(volatile void *address)
 	return (phys_addr_t)address;
 }
 
-void reserve_bootmem_region(phys_addr_t start, phys_addr_t end, int nid);
-
 static inline void totalram_pages_inc(void)
 {
 }

tools/testing/memblock/internal.h

@@ -11,9 +11,22 @@ static int memblock_debug = 1;
 
 #define pr_warn_ratelimited(fmt, ...)    printf(fmt, ##__VA_ARGS__)
 
+#define K(x) ((x) << (PAGE_SHIFT-10))
+
 bool mirrored_kernelcore = false;
 
 struct page {};
+static inline void *page_address(struct page *page)
+{
+	BUG();
+	return page;
+}
+
+static inline struct page *virt_to_page(void *virt)
+{
+	BUG();
+	return virt;
+}
 
 void memblock_free_pages(unsigned long pfn, unsigned int order)
 {
@@ -23,10 +36,34 @@ static inline void accept_memory(phys_addr_t start, unsigned long size)
 {
 }
 
-static inline unsigned long free_reserved_area(void *start, void *end,
-					       int poison, const char *s)
+unsigned long free_reserved_area(void *start, void *end, int poison, const char *s);
+void free_reserved_page(struct page *page);
+
+static inline bool deferred_pages_enabled(void)
 {
-	return 0;
+	return false;
 }
 
+#define for_each_valid_pfn(pfn, start_pfn, end_pfn)			 \
+	for ((pfn) = (start_pfn); (pfn) < (end_pfn); (pfn)++)
+
+static inline void *kasan_reset_tag(const void *addr)
+{
+	return (void *)addr;
+}
+
+static inline bool __is_kernel(unsigned long addr)
+{
+	return false;
+}
+
+#define for_each_valid_pfn(pfn, start_pfn, end_pfn)                     \
+       for ((pfn) = (start_pfn); (pfn) < (end_pfn); (pfn)++)
+
+static inline void init_deferred_page(unsigned long pfn, int nid)
+{
+}
+
+#define __SetPageReserved(p)	((void)(p))
+
 #endif

tools/testing/memblock/linux/string_helpers.h

@@ -0,0 +1,10 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_STRING_HELPERS_H_
+#define _LINUX_STRING_HELPERS_H_
+
+/*
+ * Header stub to avoid test build breakage; we don't need to
+ * actually implement string_get_size() as it's not used in the tests.
+ */
+
+#endif

tools/testing/memblock/mmzone.c

@@ -11,10 +11,6 @@ struct pglist_data *next_online_pgdat(struct pglist_data *pgdat)
 	return NULL;
 }
 
-void reserve_bootmem_region(phys_addr_t start, phys_addr_t end, int nid)
-{
-}
-
 void atomic_long_set(atomic_long_t *v, long i)
 {
 }