diff --git a/drivers/firmware/efi/libstub/arm64-stub.c b/drivers/firmware/efi/libstub/arm64-stub.c
index 577173ee1f83..83b5ae3721ea 100644
--- a/drivers/firmware/efi/libstub/arm64-stub.c
+++ b/drivers/firmware/efi/libstub/arm64-stub.c
@@ -42,26 +42,17 @@ efi_status_t check_platform_features(void)
  */
 static bool check_image_region(u64 base, u64 size)
 {
-	unsigned long map_size, desc_size, buff_size;
-	efi_memory_desc_t *memory_map;
-	struct efi_boot_memmap map;
+	struct efi_boot_memmap *map;
 	efi_status_t status;
 	bool ret = false;
 	int map_offset;
 
-	map.map =	&memory_map;
-	map.map_size =	&map_size;
-	map.desc_size =	&desc_size;
-	map.desc_ver =	NULL;
-	map.key_ptr =	NULL;
-	map.buff_size =	&buff_size;
-
 	status = efi_get_memory_map(&map);
 	if (status != EFI_SUCCESS)
 		return false;
 
-	for (map_offset = 0; map_offset < map_size; map_offset += desc_size) {
-		efi_memory_desc_t *md = (void *)memory_map + map_offset;
+	for (map_offset = 0; map_offset < map->map_size; map_offset += map->desc_size) {
+		efi_memory_desc_t *md = (void *)map->map + map_offset;
 		u64 end = md->phys_addr + md->num_pages * EFI_PAGE_SIZE;
 
 		/*
@@ -74,7 +65,7 @@ static bool check_image_region(u64 base, u64 size)
 		}
 	}
 
-	efi_bs_call(free_pool, memory_map);
+	efi_bs_call(free_pool, map);
 
 	return ret;
 }
diff --git a/drivers/firmware/efi/libstub/efi-stub-helper.c b/drivers/firmware/efi/libstub/efi-stub-helper.c
index 3d972061c1b0..85c68aa83673 100644
--- a/drivers/firmware/efi/libstub/efi-stub-helper.c
+++ b/drivers/firmware/efi/libstub/efi-stub-helper.c
@@ -419,7 +419,6 @@ char *efi_convert_cmdline(efi_loaded_image_t *image, int *cmd_line_len)
 /**
  * efi_exit_boot_services() - Exit boot services
  * @handle:	handle of the exiting image
- * @map:	pointer to receive the memory map
  * @priv:	argument to be passed to @priv_func
  * @priv_func:	function to process the memory map before exiting boot services
  *
@@ -432,14 +431,13 @@ char *efi_convert_cmdline(efi_loaded_image_t *image, int *cmd_line_len)
  *
  * Return:	status code
  */
-efi_status_t efi_exit_boot_services(void *handle,
-				    struct efi_boot_memmap *map,
-				    void *priv,
+efi_status_t efi_exit_boot_services(void *handle, void *priv,
 				    efi_exit_boot_map_processing priv_func)
 {
+	struct efi_boot_memmap *map;
 	efi_status_t status;
 
-	status = efi_get_memory_map(map);
+	status = efi_get_memory_map(&map);
 
 	if (status != EFI_SUCCESS)
 		goto fail;
@@ -451,7 +449,7 @@ efi_status_t efi_exit_boot_services(void *handle,
 	if (efi_disable_pci_dma)
 		efi_pci_disable_bridge_busmaster();
 
-	status = efi_bs_call(exit_boot_services, handle, *map->key_ptr);
+	status = efi_bs_call(exit_boot_services, handle, map->map_key);
 
 	if (status == EFI_INVALID_PARAMETER) {
 		/*
@@ -467,13 +465,13 @@ efi_status_t efi_exit_boot_services(void *handle,
 		 * buffer should account for any changes in the map so the call
 		 * to get_memory_map() is expected to succeed here.
 		 */
-		*map->map_size = *map->buff_size;
+		map->map_size = map->buff_size;
 		status = efi_bs_call(get_memory_map,
-				     map->map_size,
-				     *map->map,
-				     map->key_ptr,
-				     map->desc_size,
-				     map->desc_ver);
+				     &map->map_size,
+				     &map->map,
+				     &map->map_key,
+				     &map->desc_size,
+				     &map->desc_ver);
 
 		/* exit_boot_services() was called, thus cannot free */
 		if (status != EFI_SUCCESS)
@@ -484,7 +482,7 @@ efi_status_t efi_exit_boot_services(void *handle,
 		if (status != EFI_SUCCESS)
 			goto fail;
 
-		status = efi_bs_call(exit_boot_services, handle, *map->key_ptr);
+		status = efi_bs_call(exit_boot_services, handle, map->map_key);
 	}
 
 	/* exit_boot_services() was called, thus cannot free */
@@ -494,7 +492,7 @@ efi_status_t efi_exit_boot_services(void *handle,
 	return EFI_SUCCESS;
 
 free_map:
-	efi_bs_call(free_pool, *map->map);
+	efi_bs_call(free_pool, map);
 fail:
 	return status;
 }
diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h
index e9d466822b67..ed32055f0340 100644
--- a/drivers/firmware/efi/libstub/efistub.h
+++ b/drivers/firmware/efi/libstub/efistub.h
@@ -160,15 +160,6 @@ void efi_set_u64_split(u64 data, u32 *lo, u32 *hi)
  */
 #define EFI_MMAP_NR_SLACK_SLOTS	8
 
-struct efi_boot_memmap {
-	efi_memory_desc_t	**map;
-	unsigned long		*map_size;
-	unsigned long		*desc_size;
-	u32			*desc_ver;
-	unsigned long		*key_ptr;
-	unsigned long		*buff_size;
-};
-
 typedef struct efi_generic_dev_path efi_device_path_protocol_t;
 
 typedef void *efi_event_t;
@@ -850,9 +841,7 @@ typedef efi_status_t (*efi_exit_boot_map_processing)(
 	struct efi_boot_memmap *map,
 	void *priv);
 
-efi_status_t efi_exit_boot_services(void *handle,
-				    struct efi_boot_memmap *map,
-				    void *priv,
+efi_status_t efi_exit_boot_services(void *handle, void *priv,
 				    efi_exit_boot_map_processing priv_func);
 
 efi_status_t allocate_new_fdt_and_exit_boot(void *handle,
@@ -891,7 +880,7 @@ void efi_apply_loadoptions_quirk(const void **load_options, int *load_options_si
 
 char *efi_convert_cmdline(efi_loaded_image_t *image, int *cmd_line_len);
 
-efi_status_t efi_get_memory_map(struct efi_boot_memmap *map);
+efi_status_t efi_get_memory_map(struct efi_boot_memmap **map);
 
 efi_status_t efi_allocate_pages(unsigned long size, unsigned long *addr,
 				unsigned long max);
diff --git a/drivers/firmware/efi/libstub/fdt.c b/drivers/firmware/efi/libstub/fdt.c
index bb141be6dfce..dce9747fe4c7 100644
--- a/drivers/firmware/efi/libstub/fdt.c
+++ b/drivers/firmware/efi/libstub/fdt.c
@@ -170,25 +170,25 @@ static efi_status_t update_fdt_memmap(void *fdt, struct efi_boot_memmap *map)
 	if (node < 0)
 		return EFI_LOAD_ERROR;
 
-	fdt_val64 = cpu_to_fdt64((unsigned long)*map->map);
+	fdt_val64 = cpu_to_fdt64((unsigned long)map->map);
 
 	err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-mmap-start", fdt_val64);
 	if (err)
 		return EFI_LOAD_ERROR;
 
-	fdt_val32 = cpu_to_fdt32(*map->map_size);
+	fdt_val32 = cpu_to_fdt32(map->map_size);
 
 	err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-mmap-size", fdt_val32);
 	if (err)
 		return EFI_LOAD_ERROR;
 
-	fdt_val32 = cpu_to_fdt32(*map->desc_size);
+	fdt_val32 = cpu_to_fdt32(map->desc_size);
 
 	err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-mmap-desc-size", fdt_val32);
 	if (err)
 		return EFI_LOAD_ERROR;
 
-	fdt_val32 = cpu_to_fdt32(*map->desc_ver);
+	fdt_val32 = cpu_to_fdt32(map->desc_ver);
 
 	err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-mmap-desc-ver", fdt_val32);
 	if (err)
@@ -198,22 +198,25 @@ static efi_status_t update_fdt_memmap(void *fdt, struct efi_boot_memmap *map)
 }
 
 struct exit_boot_struct {
+	struct efi_boot_memmap	*boot_memmap;
 	efi_memory_desc_t	*runtime_map;
 	int			runtime_entry_count;
 	void			*new_fdt_addr;
 };
 
-static efi_status_t exit_boot_func(struct efi_boot_memmap *map,
-				   void *priv)
+static efi_status_t exit_boot_func(struct efi_boot_memmap *map, void *priv)
 {
 	struct exit_boot_struct *p = priv;
+
+	p->boot_memmap = map;
+
 	/*
 	 * Update the memory map with virtual addresses. The function will also
 	 * populate @runtime_map with copies of just the EFI_MEMORY_RUNTIME
 	 * entries so that we can pass it straight to SetVirtualAddressMap()
 	 */
 	if (!efi_novamap)
-		efi_get_virtmap(*map->map, *map->map_size, *map->desc_size,
+		efi_get_virtmap(map->map, map->map_size, map->desc_size,
 				p->runtime_map, &p->runtime_entry_count);
 
 	return update_fdt_memmap(p->new_fdt_addr, map);
@@ -244,20 +247,11 @@ efi_status_t allocate_new_fdt_and_exit_boot(void *handle,
 					    unsigned long fdt_addr,
 					    unsigned long fdt_size)
 {
-	unsigned long map_size, desc_size, buff_size;
+	unsigned long desc_size;
 	u32 desc_ver;
-	unsigned long mmap_key;
-	efi_memory_desc_t *memory_map;
 	efi_status_t status;
-	struct efi_boot_memmap map;
 	struct exit_boot_struct priv;
 
-	map.map_size	= &map_size;
-	map.desc_size	= &desc_size;
-	map.desc_ver	= &desc_ver;
-	map.key_ptr	= &mmap_key;
-	map.buff_size	= &buff_size;
-
 	if (!efi_novamap) {
 		status = efi_alloc_virtmap(&priv.runtime_map, &desc_size,
 					   &desc_ver);
@@ -269,7 +263,6 @@ efi_status_t allocate_new_fdt_and_exit_boot(void *handle,
 
 	efi_info("Exiting boot services...\n");
 
-	map.map = &memory_map;
 	status = efi_allocate_pages(MAX_FDT_SIZE, new_fdt_addr, ULONG_MAX);
 	if (status != EFI_SUCCESS) {
 		efi_err("Unable to allocate memory for new device tree.\n");
@@ -287,7 +280,7 @@ efi_status_t allocate_new_fdt_and_exit_boot(void *handle,
 
 	priv.new_fdt_addr = (void *)*new_fdt_addr;
 
-	status = efi_exit_boot_services(handle, &map, &priv, exit_boot_func);
+	status = efi_exit_boot_services(handle, &priv, exit_boot_func);
 
 	if (status == EFI_SUCCESS) {
 		efi_set_virtual_address_map_t *svam;
@@ -306,6 +299,7 @@ efi_status_t allocate_new_fdt_and_exit_boot(void *handle,
 		 * incoming kernel but proceed normally otherwise.
 		 */
 		if (status != EFI_SUCCESS) {
+			efi_memory_desc_t *p;
 			int l;
 
 			/*
@@ -314,8 +308,9 @@ efi_status_t allocate_new_fdt_and_exit_boot(void *handle,
 			 * the incoming kernel that no virtual translation has
 			 * been installed.
 			 */
-			for (l = 0; l < map_size; l += desc_size) {
-				efi_memory_desc_t *p = (void *)memory_map + l;
+			for (l = 0; l < priv.boot_memmap->map_size;
+			     l += priv.boot_memmap->desc_size) {
+				p = (void *)priv.boot_memmap->map + l;
 
 				if (p->attribute & EFI_MEMORY_RUNTIME)
 					p->virt_addr = 0;
diff --git a/drivers/firmware/efi/libstub/mem.c b/drivers/firmware/efi/libstub/mem.c
index feef8d4be113..c92b7dbc6dfe 100644
--- a/drivers/firmware/efi/libstub/mem.c
+++ b/drivers/firmware/efi/libstub/mem.c
@@ -5,71 +5,45 @@
 
 #include "efistub.h"
 
-static inline bool mmap_has_headroom(unsigned long buff_size,
-				     unsigned long map_size,
-				     unsigned long desc_size)
-{
-	unsigned long slack = buff_size - map_size;
-
-	return slack / desc_size >= EFI_MMAP_NR_SLACK_SLOTS;
-}
-
 /**
  * efi_get_memory_map() - get memory map
- * @map:	on return pointer to memory map
+ * @map:		pointer to memory map pointer to which to assign the
+ *			newly allocated memory map
  *
  * Retrieve the UEFI memory map. The allocated memory leaves room for
  * up to EFI_MMAP_NR_SLACK_SLOTS additional memory map entries.
  *
  * Return:	status code
  */
-efi_status_t efi_get_memory_map(struct efi_boot_memmap *map)
+efi_status_t efi_get_memory_map(struct efi_boot_memmap **map)
 {
-	efi_memory_desc_t *m = NULL;
+	struct efi_boot_memmap *m, tmp;
 	efi_status_t status;
-	unsigned long key;
-	u32 desc_version;
+	unsigned long size;
 
-	*map->desc_size =	sizeof(*m);
-	*map->map_size =	*map->desc_size * 32;
-	*map->buff_size =	*map->map_size;
-again:
-	status = efi_bs_call(allocate_pool, EFI_LOADER_DATA,
-			     *map->map_size, (void **)&m);
+	tmp.map_size = 0;
+	status = efi_bs_call(get_memory_map, &tmp.map_size, NULL, &tmp.map_key,
+			     &tmp.desc_size, &tmp.desc_ver);
+	if (status != EFI_BUFFER_TOO_SMALL)
+		return EFI_LOAD_ERROR;
+
+	size = tmp.map_size + tmp.desc_size * EFI_MMAP_NR_SLACK_SLOTS;
+	status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, sizeof(*m) + size,
+			     (void **)&m);
 	if (status != EFI_SUCCESS)
-		goto fail;
+		return status;
 
-	*map->desc_size = 0;
-	key = 0;
-	status = efi_bs_call(get_memory_map, map->map_size, m,
-			     &key, map->desc_size, &desc_version);
-	if (status == EFI_BUFFER_TOO_SMALL ||
-	    !mmap_has_headroom(*map->buff_size, *map->map_size,
-			       *map->desc_size)) {
-		efi_bs_call(free_pool, m);
-		/*
-		 * Make sure there is some entries of headroom so that the
-		 * buffer can be reused for a new map after allocations are
-		 * no longer permitted.  Its unlikely that the map will grow to
-		 * exceed this headroom once we are ready to trigger
-		 * ExitBootServices()
-		 */
-		*map->map_size += *map->desc_size * EFI_MMAP_NR_SLACK_SLOTS;
-		*map->buff_size = *map->map_size;
-		goto again;
-	}
+	m->buff_size = m->map_size = size;
+	status = efi_bs_call(get_memory_map, &m->map_size, m->map, &m->map_key,
+			     &m->desc_size, &m->desc_ver);
+	if (status != EFI_SUCCESS)
+		goto free_map;
 
-	if (status == EFI_SUCCESS) {
-		if (map->key_ptr)
-			*map->key_ptr = key;
-		if (map->desc_ver)
-			*map->desc_ver = desc_version;
-	} else {
-		efi_bs_call(free_pool, m);
-	}
+	*map = m;
+	return EFI_SUCCESS;
 
-fail:
-	*map->map = m;
+free_map:
+	efi_bs_call(free_pool, m);
 	return status;
 }
 
diff --git a/drivers/firmware/efi/libstub/randomalloc.c b/drivers/firmware/efi/libstub/randomalloc.c
index 715f37479154..5d6000c717cc 100644
--- a/drivers/firmware/efi/libstub/randomalloc.c
+++ b/drivers/firmware/efi/libstub/randomalloc.c
@@ -55,20 +55,11 @@ efi_status_t efi_random_alloc(unsigned long size,
 			      unsigned long *addr,
 			      unsigned long random_seed)
 {
-	unsigned long map_size, desc_size, total_slots = 0, target_slot;
+	unsigned long total_slots = 0, target_slot;
 	unsigned long total_mirrored_slots = 0;
-	unsigned long buff_size;
+	struct efi_boot_memmap *map;
 	efi_status_t status;
-	efi_memory_desc_t *memory_map;
 	int map_offset;
-	struct efi_boot_memmap map;
-
-	map.map =	&memory_map;
-	map.map_size =	&map_size;
-	map.desc_size =	&desc_size;
-	map.desc_ver =	NULL;
-	map.key_ptr =	NULL;
-	map.buff_size =	&buff_size;
 
 	status = efi_get_memory_map(&map);
 	if (status != EFI_SUCCESS)
@@ -80,8 +71,8 @@ efi_status_t efi_random_alloc(unsigned long size,
 	size = round_up(size, EFI_ALLOC_ALIGN);
 
 	/* count the suitable slots in each memory map entry */
-	for (map_offset = 0; map_offset < map_size; map_offset += desc_size) {
-		efi_memory_desc_t *md = (void *)memory_map + map_offset;
+	for (map_offset = 0; map_offset < map->map_size; map_offset += map->desc_size) {
+		efi_memory_desc_t *md = (void *)map->map + map_offset;
 		unsigned long slots;
 
 		slots = get_entry_num_slots(md, size, ilog2(align));
@@ -109,8 +100,8 @@ efi_status_t efi_random_alloc(unsigned long size,
 	 * to calculate the randomly chosen address, and allocate it directly
 	 * using EFI_ALLOCATE_ADDRESS.
 	 */
-	for (map_offset = 0; map_offset < map_size; map_offset += desc_size) {
-		efi_memory_desc_t *md = (void *)memory_map + map_offset;
+	for (map_offset = 0; map_offset < map->map_size; map_offset += map->desc_size) {
+		efi_memory_desc_t *md = (void *)map->map + map_offset;
 		efi_physical_addr_t target;
 		unsigned long pages;
 
@@ -133,7 +124,7 @@ efi_status_t efi_random_alloc(unsigned long size,
 		break;
 	}
 
-	efi_bs_call(free_pool, memory_map);
+	efi_bs_call(free_pool, map);
 
 	return status;
 }
diff --git a/drivers/firmware/efi/libstub/relocate.c b/drivers/firmware/efi/libstub/relocate.c
index 8ee9eb2b9039..cd80db33ab1e 100644
--- a/drivers/firmware/efi/libstub/relocate.c
+++ b/drivers/firmware/efi/libstub/relocate.c
@@ -23,21 +23,12 @@
 efi_status_t efi_low_alloc_above(unsigned long size, unsigned long align,
 				 unsigned long *addr, unsigned long min)
 {
-	unsigned long map_size, desc_size, buff_size;
-	efi_memory_desc_t *map;
+	struct efi_boot_memmap *map;
 	efi_status_t status;
 	unsigned long nr_pages;
 	int i;
-	struct efi_boot_memmap boot_map;
 
-	boot_map.map		= &map;
-	boot_map.map_size	= &map_size;
-	boot_map.desc_size	= &desc_size;
-	boot_map.desc_ver	= NULL;
-	boot_map.key_ptr	= NULL;
-	boot_map.buff_size	= &buff_size;
-
-	status = efi_get_memory_map(&boot_map);
+	status = efi_get_memory_map(&map);
 	if (status != EFI_SUCCESS)
 		goto fail;
 
@@ -52,12 +43,12 @@ efi_status_t efi_low_alloc_above(unsigned long size, unsigned long align,
 
 	size = round_up(size, EFI_ALLOC_ALIGN);
 	nr_pages = size / EFI_PAGE_SIZE;
-	for (i = 0; i < map_size / desc_size; i++) {
+	for (i = 0; i < map->map_size / map->desc_size; i++) {
 		efi_memory_desc_t *desc;
-		unsigned long m = (unsigned long)map;
+		unsigned long m = (unsigned long)map->map;
 		u64 start, end;
 
-		desc = efi_early_memdesc_ptr(m, desc_size, i);
+		desc = efi_early_memdesc_ptr(m, map->desc_size, i);
 
 		if (desc->type != EFI_CONVENTIONAL_MEMORY)
 			continue;
@@ -87,7 +78,7 @@ efi_status_t efi_low_alloc_above(unsigned long size, unsigned long align,
 		}
 	}
 
-	if (i == map_size / desc_size)
+	if (i == map->map_size / map->desc_size)
 		status = EFI_NOT_FOUND;
 
 	efi_bs_call(free_pool, map);
diff --git a/drivers/firmware/efi/libstub/x86-stub.c b/drivers/firmware/efi/libstub/x86-stub.c
index 05ae8bcc9d67..1ae1e7e576b9 100644
--- a/drivers/firmware/efi/libstub/x86-stub.c
+++ b/drivers/firmware/efi/libstub/x86-stub.c
@@ -716,32 +716,22 @@ static efi_status_t exit_boot_func(struct efi_boot_memmap *map,
 
 	efi_set_u64_split((unsigned long)efi_system_table,
 			  &p->efi->efi_systab, &p->efi->efi_systab_hi);
-	p->efi->efi_memdesc_size	= *map->desc_size;
-	p->efi->efi_memdesc_version	= *map->desc_ver;
-	efi_set_u64_split((unsigned long)*map->map,
+	p->efi->efi_memdesc_size	= map->desc_size;
+	p->efi->efi_memdesc_version	= map->desc_ver;
+	efi_set_u64_split((unsigned long)map->map,
 			  &p->efi->efi_memmap, &p->efi->efi_memmap_hi);
-	p->efi->efi_memmap_size		= *map->map_size;
+	p->efi->efi_memmap_size		= map->map_size;
 
 	return EFI_SUCCESS;
 }
 
 static efi_status_t exit_boot(struct boot_params *boot_params, void *handle)
 {
-	unsigned long map_sz, key, desc_size, buff_size;
-	efi_memory_desc_t *mem_map;
 	struct setup_data *e820ext = NULL;
 	__u32 e820ext_size = 0;
 	efi_status_t status;
-	__u32 desc_version;
-	struct efi_boot_memmap map;
 	struct exit_boot_struct priv;
 
-	map.map			= &mem_map;
-	map.map_size		= &map_sz;
-	map.desc_size		= &desc_size;
-	map.desc_ver		= &desc_version;
-	map.key_ptr		= &key;
-	map.buff_size		= &buff_size;
 	priv.boot_params	= boot_params;
 	priv.efi		= &boot_params->efi_info;
 
@@ -750,7 +740,7 @@ static efi_status_t exit_boot(struct boot_params *boot_params, void *handle)
 		return status;
 
 	/* Might as well exit boot services now */
-	status = efi_exit_boot_services(handle, &map, &priv, exit_boot_func);
+	status = efi_exit_boot_services(handle, &priv, exit_boot_func);
 	if (status != EFI_SUCCESS)
 		return status;
 
diff --git a/include/linux/efi.h b/include/linux/efi.h
index d2b84c2fec39..f1b3e0d1b3fa 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -518,6 +518,15 @@ typedef union {
 	efi_system_table_32_t mixed_mode;
 } efi_system_table_t;
 
+struct efi_boot_memmap {
+	unsigned long		map_size;
+	unsigned long		desc_size;
+	u32			desc_ver;
+	unsigned long		map_key;
+	unsigned long		buff_size;
+	efi_memory_desc_t	map[];
+};
+
 /*
  * Architecture independent structure for describing a memory map for the
  * benefit of efi_memmap_init_early(), and for passing context between
