From c06aa36fd08d398a4ee2c05f0a8da8ee85f70e56 Mon Sep 17 00:00:00 2001
From: Leif Lindholm <leif.lindholm@linaro.org>
Date: Sat, 27 Feb 2016 13:44:59 +0100
Subject: [PATCH 232/260] efidisk: Respect block_io_protocol buffer alignment
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.
Cherry-picked-from: 51f375d688529b7c1819ba40188ee52b9333887c
Resolves: rhbz#1300009
---
grub-core/disk/efi/efidisk.c | 48 +++++++++++++++++++++++++++++++++++++-------
1 file changed, 41 insertions(+), 7 deletions(-)
diff --git a/grub-core/disk/efi/efidisk.c b/grub-core/disk/efi/efidisk.c
index 845c66fa9..f04f20b84 100644
--- a/grub-core/disk/efi/efidisk.c
+++ b/grub-core/disk/efi/efidisk.c
@@ -487,8 +487,15 @@ 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);
@@ -518,15 +525,42 @@ 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
--
2.13.0