Blame SOURCES/0232-efidisk-Respect-block_io_protocol-buffer-alignment.patch

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From c06aa36fd08d398a4ee2c05f0a8da8ee85f70e56 Mon Sep 17 00:00:00 2001
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From: Leif Lindholm <leif.lindholm@linaro.org>
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Date: Sat, 27 Feb 2016 13:44:59 +0100
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Subject: [PATCH 232/261] efidisk: Respect block_io_protocol buffer alignment
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Returned from the OpenProtocol operation, the grub_efi_block_io_media
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structure contains the io_align field, specifying the minimum alignment
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required for buffers used in any data transfers with the device.
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Make grub_efidisk_readwrite() allocate a temporary buffer, aligned to
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this boundary, if the buffer passed to it does not already meet the
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requirements.
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Also sanity check the io_align field in grub_efidisk_open() for
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power-of-two-ness and bail if invalid.
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Cherry-picked-from: 51f375d688529b7c1819ba40188ee52b9333887c
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Resolves: rhbz#1300009
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---
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 grub-core/disk/efi/efidisk.c | 48 +++++++++++++++++++++++++++++++++++++-------
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 1 file changed, 41 insertions(+), 7 deletions(-)
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diff --git a/grub-core/disk/efi/efidisk.c b/grub-core/disk/efi/efidisk.c
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index 845c66fa9..f04f20b84 100644
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--- a/grub-core/disk/efi/efidisk.c
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+++ b/grub-core/disk/efi/efidisk.c
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@@ -487,8 +487,15 @@ grub_efidisk_open (const char *name, struct grub_disk *disk)
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   m = d->block_io->media;
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   /* FIXME: Probably it is better to store the block size in the disk,
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      and total sectors should be replaced with total blocks.  */
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-  grub_dprintf ("efidisk", "m = %p, last block = %llx, block size = %x\n",
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-		m, (unsigned long long) m->last_block, m->block_size);
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+  grub_dprintf ("efidisk",
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+		"m = %p, last block = %llx, block size = %x, io align = %x\n",
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+		m, (unsigned long long) m->last_block, m->block_size,
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+		m->io_align);
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+
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+  /* Ensure required buffer alignment is a power of two (or is zero). */
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+  if (m->io_align & (m->io_align - 1))
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+    return grub_error (GRUB_ERR_IO, "invalid buffer alignment %d", m->io_align);
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+
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   disk->total_sectors = m->last_block + 1;
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   /* Don't increase this value due to bug in some EFI.  */
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   disk->max_agglomerate = 0xa0000 >> (GRUB_DISK_CACHE_BITS + GRUB_DISK_SECTOR_BITS);
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@@ -518,15 +525,42 @@ grub_efidisk_readwrite (struct grub_disk *disk, grub_disk_addr_t sector,
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 {
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   struct grub_efidisk_data *d;
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   grub_efi_block_io_t *bio;
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+  grub_efi_status_t status;
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+  grub_size_t io_align, num_bytes;
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+  char *aligned_buf;
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   d = disk->data;
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   bio = d->block_io;
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-  return efi_call_5 ((wr ? bio->write_blocks : bio->read_blocks), bio,
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-		     bio->media->media_id,
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-		     (grub_efi_uint64_t) sector,
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-		     (grub_efi_uintn_t) size << disk->log_sector_size,
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-		     buf);
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+  /* Set alignment to 1 if 0 specified */
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+  io_align = bio->media->io_align ? bio->media->io_align : 1;
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+  num_bytes = size << disk->log_sector_size;
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+
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+  if ((grub_addr_t) buf & (io_align - 1))
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+    {
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+      aligned_buf = grub_memalign (io_align, num_bytes);
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+      if (! aligned_buf)
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+	return GRUB_EFI_OUT_OF_RESOURCES;
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+      if (wr)
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+	grub_memcpy (aligned_buf, buf, num_bytes);
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+    }
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+  else
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+    {
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+      aligned_buf = buf;
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+    }
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+
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+  status =  efi_call_5 ((wr ? bio->write_blocks : bio->read_blocks), bio,
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+			bio->media->media_id, (grub_efi_uint64_t) sector,
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+			(grub_efi_uintn_t) num_bytes, aligned_buf);
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+
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+  if ((grub_addr_t) buf & (io_align - 1))
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+    {
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+      if (!wr)
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+	grub_memcpy (buf, aligned_buf, num_bytes);
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+      grub_free (aligned_buf);
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+    }
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+
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+  return status;
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 }
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 static grub_err_t
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-- 
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2.13.5
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