// SPDX-License-Identifier: GPL-2.0-or-later

  /************************************************************
   * EFI GUID Partition Table handling

   *
   * http://www.uefi.org/specs/
   * http://www.intel.com/technology/efi/
   *

   * efi.[ch] by Matt Domsch <Matt_Domsch@dell.com>
   *   Copyright 2000,2001,2002,2004 Dell Inc.
   *

   * TODO:
   *
   * Changelog:

   * Mon August 5th, 2013 Davidlohr Bueso <davidlohr@hp.com>
   * - detect hybrid MBRs, tighter pMBR checking & cleanups.
   *

   * Mon Nov 09 2004 Matt Domsch <Matt_Domsch@dell.com>
   * - test for valid PMBR and valid PGPT before ever reading
   *   AGPT, allow override with 'gpt' kernel command line option.
   * - check for first/last_usable_lba outside of size of disk
   *
   * Tue  Mar 26 2002 Matt Domsch <Matt_Domsch@dell.com>
   * - Ported to 2.5.7-pre1 and 2.5.7-dj2
   * - Applied patch to avoid fault in alternate header handling
   * - cleaned up find_valid_gpt
   * - On-disk structure and copy in memory is *always* LE now - 
   *   swab fields as needed
   * - remove print_gpt_header()
   * - only use first max_p partition entries, to keep the kernel minor number
   *   and partition numbers tied.
   *
   * Mon  Feb 04 2002 Matt Domsch <Matt_Domsch@dell.com>
   * - Removed __PRIPTR_PREFIX - not being used
   *
   * Mon  Jan 14 2002 Matt Domsch <Matt_Domsch@dell.com>
   * - Ported to 2.5.2-pre11 + library crc32 patch Linus applied
   *
   * Thu Dec 6 2001 Matt Domsch <Matt_Domsch@dell.com>
   * - Added compare_gpts().
   * - moved le_efi_guid_to_cpus() back into this file.  GPT is the only
   *   thing that keeps EFI GUIDs on disk.
   * - Changed gpt structure names and members to be simpler and more Linux-like.
   * 
   * Wed Oct 17 2001 Matt Domsch <Matt_Domsch@dell.com>
   * - Removed CONFIG_DEVFS_VOLUMES_UUID code entirely per Martin Wilck
   *
   * Wed Oct 10 2001 Matt Domsch <Matt_Domsch@dell.com>
   * - Changed function comments to DocBook style per Andreas Dilger suggestion.
   *
   * Mon Oct 08 2001 Matt Domsch <Matt_Domsch@dell.com>
   * - Change read_lba() to use the page cache per Al Viro's work.
   * - print u64s properly on all architectures
   * - fixed debug_printk(), now Dprintk()
   *
   * Mon Oct 01 2001 Matt Domsch <Matt_Domsch@dell.com>
   * - Style cleanups
   * - made most functions static
   * - Endianness addition
   * - remove test for second alternate header, as it's not per spec,
   *   and is unnecessary.  There's now a method to read/write the last
   *   sector of an odd-sized disk from user space.  No tools have ever
   *   been released which used this code, so it's effectively dead.
   * - Per Asit Mallick of Intel, added a test for a valid PMBR.
   * - Added kernel command line option 'gpt' to override valid PMBR test.
   *
   * Wed Jun  6 2001 Martin Wilck <Martin.Wilck@Fujitsu-Siemens.com>
   * - added devfs volume UUID support (/dev/volumes/uuids) for
   *   mounting file systems by the partition GUID. 
   *
   * Tue Dec  5 2000 Matt Domsch <Matt_Domsch@dell.com>
   * - Moved crc32() to linux/lib, added efi_crc32().
   *
   * Thu Nov 30 2000 Matt Domsch <Matt_Domsch@dell.com>
   * - Replaced Intel's CRC32 function with an equivalent
   *   non-license-restricted version.
   *
   * Wed Oct 25 2000 Matt Domsch <Matt_Domsch@dell.com>
   * - Fixed the last_lba() call to return the proper last block
   *
   * Thu Oct 12 2000 Matt Domsch <Matt_Domsch@dell.com>
   * - Thanks to Andries Brouwer for his debugging assistance.
   * - Code works, detects all the partitions.
   *
   ************************************************************/

  #include <linux/kernel.h>

  #include <linux/crc32.h>

  #include <linux/ctype.h>

  #include <linux/math64.h>

  #include <linux/slab.h>

  #include "check.h"
  #include "efi.h"

  /* This allows a kernel command line option 'gpt' to override
   * the test for invalid PMBR.  Not __initdata because reloading
   * the partition tables happens after init too.
   */
  static int force_gpt;
  static int __init
  force_gpt_fn(char *str)
  {
  	force_gpt = 1;
  	return 1;
  }
  __setup("gpt", force_gpt_fn);
  
  
  /**
   * efi_crc32() - EFI version of crc32 function
   * @buf: buffer to calculate crc32 of

   * @len: length of buf

   *
   * Description: Returns EFI-style CRC32 value for @buf
   * 
   * This function uses the little endian Ethernet polynomial
   * but seeds the function with ~0, and xor's with ~0 at the end.
   * Note, the EFI Specification, v1.02, has a reference to
   * Dr. Dobbs Journal, May 1994 (actually it's in May 1992).
   */
  static inline u32
  efi_crc32(const void *buf, unsigned long len)
  {
  	return (crc32(~0L, buf, len) ^ ~0L);
  }
  
  /**
   * last_lba(): return number of last logical block of device
   * @bdev: block device
   * 
   * Description: Returns last LBA value on success, 0 on error.
   * This is stored (by sd and ide-geometry) in
   *  the part[0] entry for this disk, and is the number of
   *  physical sectors available on the disk.
   */

  static u64 last_lba(struct block_device *bdev)

  {
  	if (!bdev || !bdev->bd_inode)
  		return 0;

  	return div_u64(bdev->bd_inode->i_size,
  		       bdev_logical_block_size(bdev)) - 1ULL;

  }

  static inline int pmbr_part_valid(gpt_mbr_record *part)

  {

  	if (part->os_type != EFI_PMBR_OSTYPE_EFI_GPT)
  		goto invalid;
  
  	/* set to 0x00000001 (i.e., the LBA of the GPT Partition Header) */
  	if (le32_to_cpu(part->starting_lba) != GPT_PRIMARY_PARTITION_TABLE_LBA)
  		goto invalid;

  	return GPT_MBR_PROTECTIVE;

  invalid:
  	return 0;

  }
  
  /**
   * is_pmbr_valid(): test Protective MBR for validity
   * @mbr: pointer to a legacy mbr structure

   * @total_sectors: amount of sectors in the device

   *

   * Description: Checks for a valid protective or hybrid
   * master boot record (MBR). The validity of a pMBR depends
   * on all of the following properties:

   *  1) MSDOS signature is in the last two bytes of the MBR
   *  2) One partition of type 0xEE is found

   *
   * In addition, a hybrid MBR will have up to three additional
   * primary partitions, which point to the same space that's
   * marked out by up to three GPT partitions.
   *
   * Returns 0 upon invalid MBR, or GPT_MBR_PROTECTIVE or
   * GPT_MBR_HYBRID depending on the device layout.

   */

  static int is_pmbr_valid(legacy_mbr *mbr, sector_t total_sectors)

  {

  	uint32_t sz = 0;

  	int i, part = 0, ret = 0; /* invalid by default */

  	if (!mbr || le16_to_cpu(mbr->signature) != MSDOS_MBR_SIGNATURE)

  		goto done;
  
  	for (i = 0; i < 4; i++) {
  		ret = pmbr_part_valid(&mbr->partition_record[i]);
  		if (ret == GPT_MBR_PROTECTIVE) {

  			part = i;

  			/*
  			 * Ok, we at least know that there's a protective MBR,
  			 * now check if there are other partition types for
  			 * hybrid MBR.
  			 */
  			goto check_hybrid;
  		}
  	}
  
  	if (ret != GPT_MBR_PROTECTIVE)
  		goto done;
  check_hybrid:

  	for (i = 0; i < 4; i++)

  		if ((mbr->partition_record[i].os_type !=
  			EFI_PMBR_OSTYPE_EFI_GPT) &&
  		    (mbr->partition_record[i].os_type != 0x00))
  			ret = GPT_MBR_HYBRID;

  
  	/*
  	 * Protective MBRs take up the lesser of the whole disk
  	 * or 2 TiB (32bit LBA), ignoring the rest of the disk.

  	 * Some partitioning programs, nonetheless, choose to set
  	 * the size to the maximum 32-bit limitation, disregarding
  	 * the disk size.

  	 *
  	 * Hybrid MBRs do not necessarily comply with this.

  	 *
  	 * Consider a bad value here to be a warning to support dd'ing
  	 * an image from a smaller disk to a larger disk.

  	 */
  	if (ret == GPT_MBR_PROTECTIVE) {

  		sz = le32_to_cpu(mbr->partition_record[part].size_in_lba);
  		if (sz != (uint32_t) total_sectors - 1 && sz != 0xFFFFFFFF)

  			pr_debug("GPT: mbr size in lba (%u) different than whole disk (%u).
  ",
  				 sz, min_t(uint32_t,
  					   total_sectors - 1, 0xFFFFFFFF));

  	}

  done:
  	return ret;

  }
  
  /**
   * read_lba(): Read bytes from disk, starting at given LBA

   * @state: disk parsed partitions
   * @lba: the Logical Block Address of the partition table
   * @buffer: destination buffer
   * @count: bytes to read

   *

   * Description: Reads @count bytes from @state->bdev into @buffer.

   * Returns number of bytes read on success, 0 on error.
   */

  static size_t read_lba(struct parsed_partitions *state,
  		       u64 lba, u8 *buffer, size_t count)

  {
  	size_t totalreadcount = 0;

  	struct block_device *bdev = state->bdev;

  	sector_t n = lba * (bdev_logical_block_size(bdev) / 512);

  	if (!buffer || lba > last_lba(bdev))

                  return 0;
  
  	while (count) {
  		int copied = 512;
  		Sector sect;

  		unsigned char *data = read_part_sector(state, n++, &sect);

  		if (!data)
  			break;
  		if (copied > count)
  			copied = count;
  		memcpy(buffer, data, copied);
  		put_dev_sector(sect);
  		buffer += copied;
  		totalreadcount +=copied;
  		count -= copied;
  	}
  	return totalreadcount;
  }
  
  /**
   * alloc_read_gpt_entries(): reads partition entries from disk

   * @state: disk parsed partitions
   * @gpt: GPT header

   * 
   * Description: Returns ptes on success,  NULL on error.
   * Allocates space for PTEs based on information found in @gpt.
   * Notes: remember to free pte when you're done!
   */

  static gpt_entry *alloc_read_gpt_entries(struct parsed_partitions *state,
  					 gpt_header *gpt)

  {
  	size_t count;
  	gpt_entry *pte;

  
  	if (!gpt)

  		return NULL;

  	count = (size_t)le32_to_cpu(gpt->num_partition_entries) *

                  le32_to_cpu(gpt->sizeof_partition_entry);
  	if (!count)
  		return NULL;

  	pte = kmalloc(count, GFP_KERNEL);

  	if (!pte)
  		return NULL;

  	if (read_lba(state, le64_to_cpu(gpt->partition_entry_lba),

  			(u8 *) pte, count) < count) {

  		kfree(pte);
                  pte=NULL;
  		return NULL;
  	}
  	return pte;
  }
  
  /**
   * alloc_read_gpt_header(): Allocates GPT header, reads into it from disk

   * @state: disk parsed partitions
   * @lba: the Logical Block Address of the partition table

   * 
   * Description: returns GPT header on success, NULL on error.   Allocates

   * and fills a GPT header starting at @ from @state->bdev.

   * Note: remember to free gpt when finished with it.
   */

  static gpt_header *alloc_read_gpt_header(struct parsed_partitions *state,
  					 u64 lba)

  {
  	gpt_header *gpt;

  	unsigned ssz = bdev_logical_block_size(state->bdev);

  	gpt = kmalloc(ssz, GFP_KERNEL);

  	if (!gpt)
  		return NULL;

  	if (read_lba(state, lba, (u8 *) gpt, ssz) < ssz) {

  		kfree(gpt);
                  gpt=NULL;
  		return NULL;
  	}
  
  	return gpt;
  }
  
  /**
   * is_gpt_valid() - tests one GPT header and PTEs for validity

   * @state: disk parsed partitions
   * @lba: logical block address of the GPT header to test
   * @gpt: GPT header ptr, filled on return.
   * @ptes: PTEs ptr, filled on return.

   *
   * Description: returns 1 if valid,  0 on error.
   * If valid, returns pointers to newly allocated GPT header and PTEs.
   */

  static int is_gpt_valid(struct parsed_partitions *state, u64 lba,
  			gpt_header **gpt, gpt_entry **ptes)

  {
  	u32 crc, origcrc;

  	u64 lastlba, pt_size;

  	if (!ptes)

  		return 0;

  	if (!(*gpt = alloc_read_gpt_header(state, lba)))

  		return 0;
  
  	/* Check the GUID Partition Table signature */
  	if (le64_to_cpu((*gpt)->signature) != GPT_HEADER_SIGNATURE) {

  		pr_debug("GUID Partition Table Header signature is wrong:"
  			 "%lld != %lld
  ",
  			 (unsigned long long)le64_to_cpu((*gpt)->signature),
  			 (unsigned long long)GPT_HEADER_SIGNATURE);

  		goto fail;
  	}

  	/* Check the GUID Partition Table header size is too big */

  	if (le32_to_cpu((*gpt)->header_size) >
  			bdev_logical_block_size(state->bdev)) {

  		pr_debug("GUID Partition Table Header size is too large: %u > %u
  ",

  			le32_to_cpu((*gpt)->header_size),
  			bdev_logical_block_size(state->bdev));
  		goto fail;
  	}

  	/* Check the GUID Partition Table header size is too small */
  	if (le32_to_cpu((*gpt)->header_size) < sizeof(gpt_header)) {
  		pr_debug("GUID Partition Table Header size is too small: %u < %zu
  ",
  			le32_to_cpu((*gpt)->header_size),
  			sizeof(gpt_header));
  		goto fail;
  	}

  	/* Check the GUID Partition Table CRC */
  	origcrc = le32_to_cpu((*gpt)->header_crc32);
  	(*gpt)->header_crc32 = 0;
  	crc = efi_crc32((const unsigned char *) (*gpt), le32_to_cpu((*gpt)->header_size));
  
  	if (crc != origcrc) {

  		pr_debug("GUID Partition Table Header CRC is wrong: %x != %x
  ",
  			 crc, origcrc);

  		goto fail;
  	}
  	(*gpt)->header_crc32 = cpu_to_le32(origcrc);
  
  	/* Check that the my_lba entry points to the LBA that contains
  	 * the GUID Partition Table */
  	if (le64_to_cpu((*gpt)->my_lba) != lba) {

  		pr_debug("GPT my_lba incorrect: %lld != %lld
  ",
  			 (unsigned long long)le64_to_cpu((*gpt)->my_lba),
  			 (unsigned long long)lba);

  		goto fail;
  	}
  
  	/* Check the first_usable_lba and last_usable_lba are
  	 * within the disk.
  	 */

  	lastlba = last_lba(state->bdev);

  	if (le64_to_cpu((*gpt)->first_usable_lba) > lastlba) {

  		pr_debug("GPT: first_usable_lba incorrect: %lld > %lld
  ",
  			 (unsigned long long)le64_to_cpu((*gpt)->first_usable_lba),
  			 (unsigned long long)lastlba);

  		goto fail;
  	}
  	if (le64_to_cpu((*gpt)->last_usable_lba) > lastlba) {

  		pr_debug("GPT: last_usable_lba incorrect: %lld > %lld
  ",
  			 (unsigned long long)le64_to_cpu((*gpt)->last_usable_lba),
  			 (unsigned long long)lastlba);

  		goto fail;
  	}

  	if (le64_to_cpu((*gpt)->last_usable_lba) < le64_to_cpu((*gpt)->first_usable_lba)) {
  		pr_debug("GPT: last_usable_lba incorrect: %lld > %lld
  ",
  			 (unsigned long long)le64_to_cpu((*gpt)->last_usable_lba),
  			 (unsigned long long)le64_to_cpu((*gpt)->first_usable_lba));
  		goto fail;
  	}

  	/* Check that sizeof_partition_entry has the correct value */
  	if (le32_to_cpu((*gpt)->sizeof_partition_entry) != sizeof(gpt_entry)) {

  		pr_debug("GUID Partition Entry Size check failed.
  ");

  		goto fail;
  	}

  	/* Sanity check partition table size */
  	pt_size = (u64)le32_to_cpu((*gpt)->num_partition_entries) *
  		le32_to_cpu((*gpt)->sizeof_partition_entry);
  	if (pt_size > KMALLOC_MAX_SIZE) {
  		pr_debug("GUID Partition Table is too large: %llu > %lu bytes
  ",
  			 (unsigned long long)pt_size, KMALLOC_MAX_SIZE);
  		goto fail;
  	}

  	if (!(*ptes = alloc_read_gpt_entries(state, *gpt)))

  		goto fail;
  
  	/* Check the GUID Partition Entry Array CRC */

  	crc = efi_crc32((const unsigned char *) (*ptes), pt_size);

  
  	if (crc != le32_to_cpu((*gpt)->partition_entry_array_crc32)) {

  		pr_debug("GUID Partition Entry Array CRC check failed.
  ");

  		goto fail_ptes;
  	}
  
  	/* We're done, all's well */
  	return 1;
  
   fail_ptes:
  	kfree(*ptes);
  	*ptes = NULL;
   fail:
  	kfree(*gpt);
  	*gpt = NULL;
  	return 0;
  }
  
  /**
   * is_pte_valid() - tests one PTE for validity

   * @pte:pte to check
   * @lastlba: last lba of the disk

   *
   * Description: returns 1 if valid,  0 on error.
   */
  static inline int
  is_pte_valid(const gpt_entry *pte, const u64 lastlba)
  {
  	if ((!efi_guidcmp(pte->partition_type_guid, NULL_GUID)) ||
  	    le64_to_cpu(pte->starting_lba) > lastlba         ||
  	    le64_to_cpu(pte->ending_lba)   > lastlba)
  		return 0;
  	return 1;
  }
  
  /**
   * compare_gpts() - Search disk for valid GPT headers and PTEs

   * @pgpt: primary GPT header
   * @agpt: alternate GPT header
   * @lastlba: last LBA number
   *

   * Description: Returns nothing.  Sanity checks pgpt and agpt fields
   * and prints warnings on discrepancies.
   * 
   */
  static void
  compare_gpts(gpt_header *pgpt, gpt_header *agpt, u64 lastlba)
  {
  	int error_found = 0;
  	if (!pgpt || !agpt)
  		return;
  	if (le64_to_cpu(pgpt->my_lba) != le64_to_cpu(agpt->alternate_lba)) {

  		pr_warn("GPT:Primary header LBA != Alt. header alternate_lba
  ");
  		pr_warn("GPT:%lld != %lld
  ",

  		       (unsigned long long)le64_to_cpu(pgpt->my_lba),
                         (unsigned long long)le64_to_cpu(agpt->alternate_lba));
  		error_found++;
  	}
  	if (le64_to_cpu(pgpt->alternate_lba) != le64_to_cpu(agpt->my_lba)) {

  		pr_warn("GPT:Primary header alternate_lba != Alt. header my_lba
  ");
  		pr_warn("GPT:%lld != %lld
  ",

  		       (unsigned long long)le64_to_cpu(pgpt->alternate_lba),
                         (unsigned long long)le64_to_cpu(agpt->my_lba));
  		error_found++;
  	}
  	if (le64_to_cpu(pgpt->first_usable_lba) !=
              le64_to_cpu(agpt->first_usable_lba)) {

  		pr_warn("GPT:first_usable_lbas don't match.
  ");
  		pr_warn("GPT:%lld != %lld
  ",

  		       (unsigned long long)le64_to_cpu(pgpt->first_usable_lba),
                         (unsigned long long)le64_to_cpu(agpt->first_usable_lba));
  		error_found++;
  	}
  	if (le64_to_cpu(pgpt->last_usable_lba) !=
              le64_to_cpu(agpt->last_usable_lba)) {

  		pr_warn("GPT:last_usable_lbas don't match.
  ");
  		pr_warn("GPT:%lld != %lld
  ",

  		       (unsigned long long)le64_to_cpu(pgpt->last_usable_lba),
                         (unsigned long long)le64_to_cpu(agpt->last_usable_lba));
  		error_found++;
  	}
  	if (efi_guidcmp(pgpt->disk_guid, agpt->disk_guid)) {

  		pr_warn("GPT:disk_guids don't match.
  ");

  		error_found++;
  	}
  	if (le32_to_cpu(pgpt->num_partition_entries) !=
              le32_to_cpu(agpt->num_partition_entries)) {

  		pr_warn("GPT:num_partition_entries don't match: "

  		       "0x%x != 0x%x
  ",
  		       le32_to_cpu(pgpt->num_partition_entries),
  		       le32_to_cpu(agpt->num_partition_entries));
  		error_found++;
  	}
  	if (le32_to_cpu(pgpt->sizeof_partition_entry) !=
              le32_to_cpu(agpt->sizeof_partition_entry)) {

  		pr_warn("GPT:sizeof_partition_entry values don't match: "

  		       "0x%x != 0x%x
  ",
                         le32_to_cpu(pgpt->sizeof_partition_entry),
  		       le32_to_cpu(agpt->sizeof_partition_entry));
  		error_found++;
  	}
  	if (le32_to_cpu(pgpt->partition_entry_array_crc32) !=
              le32_to_cpu(agpt->partition_entry_array_crc32)) {

  		pr_warn("GPT:partition_entry_array_crc32 values don't match: "

  		       "0x%x != 0x%x
  ",
                         le32_to_cpu(pgpt->partition_entry_array_crc32),
  		       le32_to_cpu(agpt->partition_entry_array_crc32));
  		error_found++;
  	}
  	if (le64_to_cpu(pgpt->alternate_lba) != lastlba) {

  		pr_warn("GPT:Primary header thinks Alt. header is not at the end of the disk.
  ");
  		pr_warn("GPT:%lld != %lld
  ",

  			(unsigned long long)le64_to_cpu(pgpt->alternate_lba),
  			(unsigned long long)lastlba);
  		error_found++;
  	}
  
  	if (le64_to_cpu(agpt->my_lba) != lastlba) {

  		pr_warn("GPT:Alternate GPT header not at the end of the disk.
  ");
  		pr_warn("GPT:%lld != %lld
  ",

  			(unsigned long long)le64_to_cpu(agpt->my_lba),
  			(unsigned long long)lastlba);
  		error_found++;
  	}
  
  	if (error_found)

  		pr_warn("GPT: Use GNU Parted to correct GPT errors.
  ");

  	return;
  }
  
  /**
   * find_valid_gpt() - Search disk for valid GPT headers and PTEs

   * @state: disk parsed partitions
   * @gpt: GPT header ptr, filled on return.
   * @ptes: PTEs ptr, filled on return.
   *

   * Description: Returns 1 if valid, 0 on error.
   * If valid, returns pointers to newly allocated GPT header and PTEs.
   * Validity depends on PMBR being valid (or being overridden by the
   * 'gpt' kernel command line option) and finding either the Primary
   * GPT header and PTEs valid, or the Alternate GPT header and PTEs
   * valid.  If the Primary GPT header is not valid, the Alternate GPT header
   * is not checked unless the 'gpt' kernel command line option is passed.
   * This protects against devices which misreport their size, and forces
   * the user to decide to use the Alternate GPT.
   */

  static int find_valid_gpt(struct parsed_partitions *state, gpt_header **gpt,
  			  gpt_entry **ptes)

  {
  	int good_pgpt = 0, good_agpt = 0, good_pmbr = 0;
  	gpt_header *pgpt = NULL, *agpt = NULL;
  	gpt_entry *pptes = NULL, *aptes = NULL;

  	legacy_mbr *legacymbr;

  	sector_t total_sectors = i_size_read(state->bdev->bd_inode) >> 9;

  	u64 lastlba;

  
  	if (!ptes)

  		return 0;

  	lastlba = last_lba(state->bdev);

          if (!force_gpt) {

  		/* This will be added to the EFI Spec. per Intel after v1.02. */
  		legacymbr = kzalloc(sizeof(*legacymbr), GFP_KERNEL);
  		if (!legacymbr)
  			goto fail;
  
  		read_lba(state, 0, (u8 *)legacymbr, sizeof(*legacymbr));

  		good_pmbr = is_pmbr_valid(legacymbr, total_sectors);

  		kfree(legacymbr);
  
  		if (!good_pmbr)
  			goto fail;
  
  		pr_debug("Device has a %s MBR
  ",
  			 good_pmbr == GPT_MBR_PROTECTIVE ?
  						"protective" : "hybrid");
  	}

  	good_pgpt = is_gpt_valid(state, GPT_PRIMARY_PARTITION_TABLE_LBA,

  				 &pgpt, &pptes);
          if (good_pgpt)

  		good_agpt = is_gpt_valid(state,

  					 le64_to_cpu(pgpt->alternate_lba),
  					 &agpt, &aptes);
          if (!good_agpt && force_gpt)

                  good_agpt = is_gpt_valid(state, lastlba, &agpt, &aptes);

  
          /* The obviously unsuccessful case */
          if (!good_pgpt && !good_agpt)
                  goto fail;
  
          compare_gpts(pgpt, agpt, lastlba);
  
          /* The good cases */
          if (good_pgpt) {
                  *gpt  = pgpt;
                  *ptes = pptes;
                  kfree(agpt);
                  kfree(aptes);

  		if (!good_agpt)

                          pr_warn("Alternate GPT is invalid, using primary GPT.
  ");

                  return 1;
          }
          else if (good_agpt) {
                  *gpt  = agpt;
                  *ptes = aptes;
                  kfree(pgpt);
                  kfree(pptes);

  		pr_warn("Primary GPT is invalid, using alternate GPT.
  ");

                  return 1;
          }
  
   fail:
          kfree(pgpt);
          kfree(agpt);
          kfree(pptes);
          kfree(aptes);
          *gpt = NULL;
          *ptes = NULL;
          return 0;
  }
  
  /**

   * utf16_le_to_7bit(): Naively converts a UTF-16LE string to 7-bit ASCII characters
   * @in: input UTF-16LE string
   * @size: size of the input string
   * @out: output string ptr, should be capable to store @size+1 characters
   *
   * Description: Converts @size UTF16-LE symbols from @in string to 7-bit
   * ASCII characters and stores them to @out. Adds trailing zero to @out array.
   */
  static void utf16_le_to_7bit(const __le16 *in, unsigned int size, u8 *out)
  {
  	unsigned int i = 0;
  
  	out[size] = 0;
  
  	while (i < size) {
  		u8 c = le16_to_cpu(in[i]) & 0xff;
  
  		if (c && !isprint(c))
  			c = '!';
  		out[i] = c;
  		i++;
  	}
  }
  
  /**

   * efi_partition(struct parsed_partitions *state)

   * @state: disk parsed partitions

   *
   * Description: called from check.c, if the disk contains GPT
   * partitions, sets up partition entries in the kernel.
   *
   * If the first block on the disk is a legacy MBR,
   * it will get handled by msdos_partition().
   * If it's a Protective MBR, we'll handle it here.
   *
   * We do not create a Linux partition for GPT, but
   * only for the actual data partitions.
   * Returns:
   * -1 if unable to read the partition table
   *  0 if this isn't our partition table
   *  1 if successful
   *
   */

  int efi_partition(struct parsed_partitions *state)

  {
  	gpt_header *gpt = NULL;
  	gpt_entry *ptes = NULL;
  	u32 i;

  	unsigned ssz = bdev_logical_block_size(state->bdev) / 512;

  	if (!find_valid_gpt(state, &gpt, &ptes) || !gpt || !ptes) {

  		kfree(gpt);
  		kfree(ptes);
  		return 0;
  	}

  	pr_debug("GUID Partition Table is valid!  Yea!
  ");

  
  	for (i = 0; i < le32_to_cpu(gpt->num_partition_entries) && i < state->limit-1; i++) {

  		struct partition_meta_info *info;

  		unsigned label_max;

  		u64 start = le64_to_cpu(ptes[i].starting_lba);
  		u64 size = le64_to_cpu(ptes[i].ending_lba) -
  			   le64_to_cpu(ptes[i].starting_lba) + 1ULL;

  		if (!is_pte_valid(&ptes[i], last_lba(state->bdev)))

  			continue;

  		put_partition(state, i+1, start * ssz, size * ssz);

  
  		/* If this is a RAID volume, tell md */

  		if (!efi_guidcmp(ptes[i].partition_type_guid, PARTITION_LINUX_RAID_GUID))

  			state->parts[i + 1].flags = ADDPART_FLAG_RAID;

  
  		info = &state->parts[i + 1].info;

  		efi_guid_to_str(&ptes[i].unique_partition_guid, info->uuid);

  
  		/* Naively convert UTF16-LE to 7 bits. */

  		label_max = min(ARRAY_SIZE(info->volname) - 1,
  				ARRAY_SIZE(ptes[i].partition_name));

  		utf16_le_to_7bit(ptes[i].partition_name, label_max, info->volname);

  		state->parts[i + 1].has_info = true;

  	}
  	kfree(ptes);
  	kfree(gpt);

  	strlcat(state->pp_buf, "
  ", PAGE_SIZE);

  	return 1;
  }