[parted-devel] [PATCH v2] gpt: support padding between Partition Header and Partition Table.

[Tzu-Jung Lee]

Some SoC requires their booting code at a specific location, which
might conflict with the default layout of GPT.

Supporting a specified PartitionEntryLBA is required in this case.

Signed-off-by: Tzu-Jung Lee <roylee17 at currant.com>

diff --git a/include/parted/device.in.h b/include/parted/device.in.h
index 82d4104..1ce7a97 100644
--- a/include/parted/device.in.h
+++ b/include/parted/device.in.h
@@ -87,6 +87,8 @@ struct _PedDevice {
         int             dirty;
         int             boot_dirty;
 
+        int             pte_lba;
+
         PedCHSGeometry  hw_geom;
         PedCHSGeometry  bios_geom;
         short           host, did;
diff --git a/libparted/labels/gpt.c b/libparted/labels/gpt.c
index d69377a..0b92824 100644
--- a/libparted/labels/gpt.c
+++ b/libparted/labels/gpt.c
@@ -499,6 +499,7 @@ gpt_probe (const PedDevice *dev)
       || ped_device_read (dev, pth_raw, dev->length - 1, GPT_HEADER_SECTORS))
     {
       GuidPartitionTableHeader_t *gpt = pth_new_from_raw (dev, pth_raw);
+      ((PedDevice*)dev)->pte_lba = gpt->PartitionEntryLBA;
       if (gpt->Signature == PED_CPU_TO_LE64 (GPT_HEADER_SIGNATURE))
         gpt_sig_found = 1;
       pth_free (gpt);
@@ -520,7 +521,7 @@ gpt_alloc (const PedDevice *dev)
     goto error;
 
   data_start = 2 + GPT_DEFAULT_PARTITION_ENTRY_ARRAY_SIZE / dev->sector_size;
-  data_end = dev->length - 2
+  data_end = dev->length - dev->pte_lba
     - GPT_DEFAULT_PARTITION_ENTRY_ARRAY_SIZE / dev->sector_size;
 
   /* If the device is too small to accommodate GPT headers and one data
@@ -1192,7 +1193,7 @@ _generate_header (const PedDisk *disk, int alternate, uint32_t ptes_crc,
     {
       gpt->MyLBA = PED_CPU_TO_LE64 (1);
       gpt->AlternateLBA = PED_CPU_TO_LE64 (gpt_disk_data->AlternateLBA);
-      gpt->PartitionEntryLBA = PED_CPU_TO_LE64 (2);
+      gpt->PartitionEntryLBA = PED_CPU_TO_LE64 (disk->dev->pte_lba);
     }
 
   gpt->FirstUsableLBA = PED_CPU_TO_LE64 (gpt_disk_data->data_area.start);
@@ -1284,7 +1285,7 @@ gpt_write (const PedDisk *disk)
   free (pth_raw);
   if (!write_ok)
     goto error_free_ptes;
-  if (!ped_device_write (disk->dev, ptes, 2, ptes_sectors))
+  if (!ped_device_write (disk->dev, ptes, disk->dev->pte_lba, ptes_sectors))
     goto error_free_ptes;
 
   /* Write Alternate PTH & PTEs */
@@ -1962,7 +1963,7 @@ gpt_get_max_primary_partition_count (const PedDisk *disk)
  *
  * The number of possible partitions or supported partitions is:
  * SP = FirstUsableLBA*Blocksize - 2*Blocksize / SizeOfPartitionEntry
- * SP = Blocksize(FirstusableLBA - 2) / SizeOfPartitoinEntry
+ * SP = Blocksize(FirstusableLBA - PartitionEntryLBA) / SizeOfPartitoinEntry
  */
 static bool
 gpt_get_max_supported_partition_count (const PedDisk *disk, int *max_n)
@@ -1986,7 +1987,7 @@ gpt_get_max_supported_partition_count (const PedDisk *disk, int *max_n)
         = PED_CPU_TO_LE32 (sizeof (GuidPartitionEntry_t));
     }
 
-  *max_n = (disk->dev->sector_size * (PED_LE64_TO_CPU (pth->FirstUsableLBA) - 2)
+  *max_n = (disk->dev->sector_size * (PED_LE64_TO_CPU (pth->FirstUsableLBA) - PED_LE64_TO_CPU (pth->PartitionEntryLBA))
             / PED_LE32_TO_CPU (pth->SizeOfPartitionEntry));
   pth_free (pth);
   return true;
diff --git a/parted/parted.c b/parted/parted.c
index a9426c4..d5cc53d 100644
--- a/parted/parted.c
+++ b/parted/parted.c
@@ -524,6 +524,8 @@ do_mklabel (PedDevice** dev, PedDisk** diskp)
         if (!command_line_get_disk_type (_("New disk label type?"), &type))
                 goto error;
 
+        (*dev)->pte_lba = 2;
+
         if (disk) {
                 if (!_disk_warn_busy (disk))
                         goto error;
-- 
2.7.4