1 files changed, 19 insertions, 17 deletions

diff --git a/drivers/firmware/efi/libstub/randomalloc.c b/drivers/firmware/efi/libstub/randomalloc.c
index 724155b9e10d..9fb5869896be 100644
--- a/drivers/firmware/efi/libstub/randomalloc.c
+++ b/drivers/firmware/efi/libstub/randomalloc.c
@@ -55,21 +55,13 @@ 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 buff_size;
+	unsigned long total_slots = 0, target_slot;
+	unsigned long total_mirrored_slots = 0;
+	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);
+	status = efi_get_memory_map(&map, false);
 	if (status != EFI_SUCCESS)
 		return status;
 
@@ -79,15 +71,21 @@ 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));
 		MD_NUM_SLOTS(md) = slots;
 		total_slots += slots;
+		if (md->attribute & EFI_MEMORY_MORE_RELIABLE)
+			total_mirrored_slots += slots;
 	}
 
+	/* consider only mirrored slots for randomization if any exist */
+	if (total_mirrored_slots > 0)
+		total_slots = total_mirrored_slots;
+
 	/* find a random number between 0 and total_slots */
 	target_slot = (total_slots * (u64)(random_seed & U32_MAX)) >> 32;
 
@@ -102,11 +100,15 @@ 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;
 
+		if (total_mirrored_slots > 0 &&
+		    !(md->attribute & EFI_MEMORY_MORE_RELIABLE))
+			continue;
+
 		if (target_slot >= MD_NUM_SLOTS(md)) {
 			target_slot -= MD_NUM_SLOTS(md);
 			continue;
@@ -122,7 +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;
 }