diff options
Diffstat (limited to 'drivers/firmware/efi/libstub/random.c')
| -rw-r--r-- | drivers/firmware/efi/libstub/random.c | 13 |
1 files changed, 7 insertions, 6 deletions
diff --git a/drivers/firmware/efi/libstub/random.c b/drivers/firmware/efi/libstub/random.c index 3a3feacc329f..7e72954d5860 100644 --- a/drivers/firmware/efi/libstub/random.c +++ b/drivers/firmware/efi/libstub/random.c @@ -45,19 +45,20 @@ static unsigned long get_entry_num_slots(efi_memory_desc_t *md, unsigned long align_shift) { unsigned long align = 1UL << align_shift; - u64 start, end; + u64 first_slot, last_slot, region_end; if (md->type != EFI_CONVENTIONAL_MEMORY) return 0; - start = round_up(md->phys_addr, align); - end = round_down(md->phys_addr + md->num_pages * EFI_PAGE_SIZE - size, - align); + region_end = min((u64)ULONG_MAX, md->phys_addr + md->num_pages*EFI_PAGE_SIZE - 1); - if (start > end) + first_slot = round_up(md->phys_addr, align); + last_slot = round_down(region_end - size + 1, align); + + if (first_slot > last_slot) return 0; - return (end - start + 1) >> align_shift; + return ((unsigned long)(last_slot - first_slot) >> align_shift) + 1; } /* |