@@ -493,8 +493,15 @@ grub_efidisk_open (const char *name, struct grub_disk *disk)
m = d->block_io->media;
/* FIXME: Probably it is better to store the block size in the disk,
and total sectors should be replaced with total blocks. */
- grub_dprintf ("efidisk", "m = %p, last block = %llx, block size = %x\n",
- m, (unsigned long long) m->last_block, m->block_size);
+ grub_dprintf ("efidisk",
+ "m = %p, last block = %llx, block size = %x, io align = %x\n",
+ m, (unsigned long long) m->last_block, m->block_size,
+ m->io_align);
+
+ /* Ensure required buffer alignment is a power of two (or is zero). */
+ if (m->io_align & (m->io_align - 1))
+ return grub_error (GRUB_ERR_IO, "invalid buffer alignment %d", m->io_align);
+
disk->total_sectors = m->last_block + 1;
/* Don't increase this value due to bug in some EFI. */
disk->max_agglomerate = 0xa0000 >> (GRUB_DISK_CACHE_BITS + GRUB_DISK_SECTOR_BITS);
@@ -524,15 +531,42 @@ grub_efidisk_readwrite (struct grub_disk *disk, grub_disk_addr_t sector,
{
struct grub_efidisk_data *d;
grub_efi_block_io_t *bio;
+ grub_efi_status_t status;
+ grub_size_t io_align, num_bytes;
+ char *aligned_buf;
d = disk->data;
bio = d->block_io;
- return efi_call_5 ((wr ? bio->write_blocks : bio->read_blocks), bio,
- bio->media->media_id,
- (grub_efi_uint64_t) sector,
- (grub_efi_uintn_t) size << disk->log_sector_size,
- buf);
+ /* Set alignment to 1 if 0 specified */
+ io_align = bio->media->io_align ? bio->media->io_align : 1;
+ num_bytes = size << disk->log_sector_size;
+
+ if ((grub_addr_t) buf & (io_align - 1))
+ {
+ aligned_buf = grub_memalign (io_align, num_bytes);
+ if (! aligned_buf)
+ return GRUB_EFI_OUT_OF_RESOURCES;
+ if (wr)
+ grub_memcpy (aligned_buf, buf, num_bytes);
+ }
+ else
+ {
+ aligned_buf = buf;
+ }
+
+ status = efi_call_5 ((wr ? bio->write_blocks : bio->read_blocks), bio,
+ bio->media->media_id, (grub_efi_uint64_t) sector,
+ (grub_efi_uintn_t) num_bytes, aligned_buf);
+
+ if ((grub_addr_t) buf & (io_align - 1))
+ {
+ if (!wr)
+ grub_memcpy (buf, aligned_buf, num_bytes);
+ grub_free (aligned_buf);
+ }
+
+ return status;
}
static grub_err_t
Returned from the OpenProtocol operation, the grub_efi_block_io_media structure contains the io_align field, specifying the minimum alignment required for buffers used in any data transfers with the device. Make grub_efidisk_readwrite() allocate a temporary buffer, aligned to this boundary, if the buffer passed to it does not already meet the requirements. Also sanity check the io_align field in grub_efidisk_open() for power-of-two-ness and bail if invalid. Reported-by: Jeremy Linton <jeremy.linton@arm.com> --- v4 - Improved alignment checking as suggested by Vladimir, and moved the error exit as requested by Andrei. grub-core/disk/efi/efidisk.c | 48 +++++++++++++++++++++++++++++++++++++------- 1 file changed, 41 insertions(+), 7 deletions(-) -- 2.1.4 _______________________________________________ Grub-devel mailing list Grub-devel@gnu.org https://lists.gnu.org/mailman/listinfo/grub-devel