Piotr Wilczek p.wilczek@samsung.com writes:
In this patch static variable and memcpy instead of an assignment are used to avoid unaligned access exception on some ARM platforms.
Signed-off-by: Piotr Wilczek p.wilczek@samsung.com Signed-off-by: Kyungmin Park kyungmin.park@samsung.com CC: Tom Rini trini@ti.com
disk/part_efi.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/disk/part_efi.c b/disk/part_efi.c index b7524d6..303b8af 100644 --- a/disk/part_efi.c +++ b/disk/part_efi.c @@ -224,7 +224,8 @@ static int set_protective_mbr(block_dev_desc_t *dev_desc) p_mbr->signature = MSDOS_MBR_SIGNATURE; p_mbr->partition_record[0].sys_ind = EFI_PMBR_OSTYPE_EFI_GPT; p_mbr->partition_record[0].start_sect = 1;
- p_mbr->partition_record[0].nr_sects = (u32) dev_desc->lba;
- memcpy(&p_mbr->partition_record[0].nr_sects, &dev_desc->lba,
sizeof(dev_desc->lba));
Why is this assignment problematic? Note that the compiler may optimise the memcpy() call into a plain assignment including any alignment assumptions it was making in the original code.
The correct fix is either to ensure that pointers are properly aligned or that things are annotated as potentially unaligned, whichever is more appropriate.