1 files changed, 19 insertions, 9 deletions

diff --git a/drivers/firmware/efi/libstub/randomalloc.c b/drivers/firmware/efi/libstub/randomalloc.c
index 1692d19ae80f..fd80b2f3233a 100644
--- a/drivers/firmware/efi/libstub/randomalloc.c
+++ b/drivers/firmware/efi/libstub/randomalloc.c
@@ -16,7 +16,8 @@
  */
 static unsigned long get_entry_num_slots(efi_memory_desc_t *md,
 					 unsigned long size,
-					 unsigned long align_shift)
+					 unsigned long align_shift,
+					 u64 alloc_min, u64 alloc_max)
 {
 	unsigned long align = 1UL << align_shift;
 	u64 first_slot, last_slot, region_end;
@@ -24,16 +25,19 @@ static unsigned long get_entry_num_slots(efi_memory_desc_t *md,
 	if (md->type != EFI_CONVENTIONAL_MEMORY)
 		return 0;
 
+	if (md->attribute & EFI_MEMORY_HOT_PLUGGABLE)
+		return 0;
+
 	if (efi_soft_reserve_enabled() &&
 	    (md->attribute & EFI_MEMORY_SP))
 		return 0;
 
 	region_end = min(md->phys_addr + md->num_pages * EFI_PAGE_SIZE - 1,
-			 (u64)EFI_ALLOC_LIMIT);
+			 alloc_max);
 	if (region_end < size)
 		return 0;
 
-	first_slot = round_up(md->phys_addr, align);
+	first_slot = round_up(max(md->phys_addr, alloc_min), align);
 	last_slot = round_down(region_end - size + 1, align);
 
 	if (first_slot > last_slot)
@@ -54,11 +58,13 @@ efi_status_t efi_random_alloc(unsigned long size,
 			      unsigned long align,
 			      unsigned long *addr,
 			      unsigned long random_seed,
-			      int memory_type)
+			      int memory_type,
+			      unsigned long alloc_min,
+			      unsigned long alloc_max)
 {
+	struct efi_boot_memmap *map __free(efi_pool) = NULL;
 	unsigned long total_slots = 0, target_slot;
 	unsigned long total_mirrored_slots = 0;
-	struct efi_boot_memmap *map;
 	efi_status_t status;
 	int map_offset;
 
@@ -69,6 +75,10 @@ efi_status_t efi_random_alloc(unsigned long size,
 	if (align < EFI_ALLOC_ALIGN)
 		align = EFI_ALLOC_ALIGN;
 
+	/* Avoid address 0x0, as it can be mistaken for NULL */
+	if (alloc_min == 0)
+		alloc_min = align;
+
 	size = round_up(size, EFI_ALLOC_ALIGN);
 
 	/* count the suitable slots in each memory map entry */
@@ -76,7 +86,8 @@ efi_status_t efi_random_alloc(unsigned long size,
 		efi_memory_desc_t *md = (void *)map->map + map_offset;
 		unsigned long slots;
 
-		slots = get_entry_num_slots(md, size, ilog2(align));
+		slots = get_entry_num_slots(md, size, ilog2(align), alloc_min,
+					    alloc_max);
 		MD_NUM_SLOTS(md) = slots;
 		total_slots += slots;
 		if (md->attribute & EFI_MEMORY_MORE_RELIABLE)
@@ -101,6 +112,7 @@ efi_status_t efi_random_alloc(unsigned long size,
 	 * to calculate the randomly chosen address, and allocate it directly
 	 * using EFI_ALLOCATE_ADDRESS.
 	 */
+	status = EFI_OUT_OF_RESOURCES;
 	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;
@@ -115,7 +127,7 @@ efi_status_t efi_random_alloc(unsigned long size,
 			continue;
 		}
 
-		target = round_up(md->phys_addr, align) + target_slot * align;
+		target = round_up(max_t(u64, md->phys_addr, alloc_min), align) + target_slot * align;
 		pages = size / EFI_PAGE_SIZE;
 
 		status = efi_bs_call(allocate_pages, EFI_ALLOCATE_ADDRESS,
@@ -125,7 +137,5 @@ efi_status_t efi_random_alloc(unsigned long size,
 		break;
 	}
 
-	efi_bs_call(free_pool, map);
-
 	return status;
 }