patch-2.4.20 linux-2.4.20/fs/partitions/efi.c

Next file: linux-2.4.20/fs/partitions/efi.h
Previous file: linux-2.4.20/fs/partitions/check.c
Back to the patch index
Back to the overall index

diff -urN linux-2.4.19/fs/partitions/efi.c linux-2.4.20/fs/partitions/efi.c
@@ -0,0 +1,804 @@
+/************************************************************
+ * EFI GUID Partition Table handling
+ * Per Intel EFI Specification v1.02
+ * http://developer.intel.com/technology/efi/efi.htm
+ * efi.[ch] by Matt Domsch <Matt_Domsch@dell.com>
+ *   Copyright 2000,2001,2002 Dell Computer Corporation
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ *
+ * TODO:
+ *
+ * Changelog:
+ * Wed  Mar 27 2002 Matt Domsch <Matt_Domsch@dell.com>
+ * - Ported to 2.5.7-pre1 and 2.4.18
+ * - 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.
+ * - 2.4.18 patch needs own crc32() function - there's no official
+ *   lib/crc32.c in 2.4.x.
+ *
+ * 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/config.h>
+#include <linux/fs.h>
+#include <linux/genhd.h>
+#include <linux/kernel.h>
+#include <linux/major.h>
+#include <linux/string.h>
+#include <linux/blk.h>
+#include <linux/blkpg.h>
+#include <linux/slab.h>
+#include <linux/smp_lock.h>
+#include <linux/init.h>
+#include <asm/system.h>
+#include <asm/byteorder.h>
+#include "check.h"
+#include "efi.h"
+
+#if CONFIG_BLK_DEV_MD
+extern void md_autodetect_dev(kdev_t dev);
+#endif
+
+/* Handle printing of 64-bit values */
+/* Borrowed from /usr/include/inttypes.h */
+# if BITS_PER_LONG == 64 
+#  define __PRI64_PREFIX	"l"
+# else
+#  define __PRI64_PREFIX	"ll"
+# endif
+# define PRIx64		__PRI64_PREFIX "x"
+
+
+#undef EFI_DEBUG
+#ifdef EFI_DEBUG
+#define Dprintk(x...) printk(KERN_DEBUG x)
+#else
+#define Dprintk(x...)
+#endif
+
+/* 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);
+
+
+/*
+ * There are multiple 16-bit CRC polynomials in common use, but this is
+ * *the* standard CRC-32 polynomial, first popularized by Ethernet.
+ * x^32+x^26+x^23+x^22+x^16+x^12+x^11+x^10+x^8+x^7+x^5+x^4+x^2+x^1+x^0
+ */
+#define CRCPOLY_LE 0xedb88320
+/* How many bits at a time to use.  Requires a table of 4<<CRC_xx_BITS bytes. */
+/* For less performance-sensitive, use 4 */
+#define CRC_LE_BITS 8
+static u32 *crc32table_le;
+
+/**
+ * crc32init_le() - allocate and initialize LE table data
+ *
+ * crc is the crc of the byte i; other entries are filled in based on the
+ * fact that crctable[i^j] = crctable[i] ^ crctable[j].
+ *
+ */
+static int __init crc32init_le(void)
+{
+	unsigned i, j;
+	u32 crc = 1;
+
+	crc32table_le =
+	    kmalloc((1 << CRC_LE_BITS) * sizeof(u32), GFP_KERNEL);
+	if (!crc32table_le)
+		return 1;
+	crc32table_le[0] = 0;
+
+	for (i = 1 << (CRC_LE_BITS - 1); i; i >>= 1) {
+		crc = (crc >> 1) ^ ((crc & 1) ? CRCPOLY_LE : 0);
+		for (j = 0; j < 1 << CRC_LE_BITS; j += 2 * i)
+			crc32table_le[i + j] = crc ^ crc32table_le[j];
+	}
+	return 0;
+}
+
+/**
+ * crc32cleanup_le(): free LE table data
+ */
+static void __exit crc32cleanup_le(void)
+{
+	if (crc32table_le) kfree(crc32table_le);
+	crc32table_le = NULL;
+}
+
+__initcall(crc32init_le);
+__exitcall(crc32cleanup_le);
+
+/**
+ * crc32_le() - Calculate bitwise little-endian Ethernet AUTODIN II CRC32
+ * @crc - seed value for computation.  ~0 for Ethernet, sometimes 0 for
+ *        other uses, or the previous crc32 value if computing incrementally.
+ * @p   - pointer to buffer over which CRC is run
+ * @len - length of buffer @p
+ * 
+ */
+static u32 crc32_le(u32 crc, unsigned char const *p, size_t len)
+{
+	while (len--) {
+		crc = (crc >> 8) ^ crc32table_le[(crc ^ *p++) & 255];
+	}
+	return crc;
+}
+
+
+/**
+ * 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_le(~0L, buf, len) ^ ~0L);
+}
+
+/**
+ * is_pmbr_valid(): test Protective MBR for validity
+ * @mbr: pointer to a legacy mbr structure
+ *
+ * Description: Returns 1 if PMBR is valid, 0 otherwise.
+ * Validity depends on two things:
+ *  1) MSDOS signature is in the last two bytes of the MBR
+ *  2) One partition of type 0xEE is found
+ */
+static int
+is_pmbr_valid(legacy_mbr *mbr)
+{
+	int i, found = 0, signature = 0;
+	if (!mbr)
+		return 0;
+	signature = (le16_to_cpu(mbr->signature) == MSDOS_MBR_SIGNATURE);
+	for (i = 0; signature && i < 4; i++) {
+		if (mbr->partition_record[i].sys_ind ==
+                    EFI_PMBR_OSTYPE_EFI_GPT) {
+			found = 1;
+			break;
+		}
+	}
+	return (signature && found);
+}
+
+/**
+ * last_lba(): return number of last logical block of device
+ * @hd: gendisk with partition list
+ * @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 gendisk *hd, struct block_device *bdev)
+{
+	if (!hd || !hd->part || !bdev)
+		return 0;
+	return hd->part[MINOR(to_kdev_t(bdev->bd_dev))].nr_sects - 1;
+}
+
+/**
+ * read_lba(): Read bytes from disk, starting at given LBA
+ * @hd
+ * @bdev
+ * @lba
+ * @buffer
+ * @size_t
+ *
+ * Description:  Reads @count bytes from @bdev into @buffer.
+ * Returns number of bytes read on success, 0 on error.
+ */
+static size_t
+read_lba(struct gendisk *hd, struct block_device *bdev, u64 lba,
+	 u8 * buffer, size_t count)
+{
+
+	size_t totalreadcount = 0, bytesread = 0;
+	unsigned long blocksize;
+	int i;
+	Sector sect;
+	unsigned char *data = NULL;
+
+	if (!hd || !bdev || !buffer || !count)
+		return 0;
+
+	blocksize = get_hardsect_size(to_kdev_t(bdev->bd_dev));
+	if (!blocksize)
+		blocksize = 512;
+
+	for (i = 0; count > 0; i++) {
+		data = read_dev_sector(bdev, lba, &sect);
+		if (!data)
+			return totalreadcount;
+
+		bytesread =
+		    PAGE_CACHE_SIZE - (data -
+				       (unsigned char *) page_address(sect.v));
+		bytesread = min(bytesread, count);
+		memcpy(buffer, data, bytesread);
+		put_dev_sector(sect);
+
+		buffer += bytesread;
+		totalreadcount += bytesread;
+		count -= bytesread;
+		lba += (bytesread / blocksize);
+	}
+	return totalreadcount;
+}
+
+
+/**
+ * alloc_read_gpt_entries(): reads partition entries from disk
+ * @hd
+ * @bdev
+ * @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 gendisk *hd,
+		       struct block_device *bdev, gpt_header *gpt)
+{
+	size_t count;
+	gpt_entry *pte;
+	if (!hd || !bdev || !gpt)
+		return NULL;
+
+	count = 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;
+	memset(pte, 0, count);
+
+	if (read_lba(hd, bdev, 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
+ * @hd
+ * @bdev
+ * @lba is 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 @bdev.
+ * Note: remember to free gpt when finished with it.
+ */
+static gpt_header *
+alloc_read_gpt_header(struct gendisk *hd, struct block_device *bdev, u64 lba)
+{
+	gpt_header *gpt;
+	if (!hd || !bdev)
+		return NULL;
+
+	gpt = kmalloc(sizeof (gpt_header), GFP_KERNEL);
+	if (!gpt)
+		return NULL;
+	memset(gpt, 0, sizeof (gpt_header));
+
+	if (read_lba(hd, bdev, lba, (u8 *) gpt,
+		     sizeof (gpt_header)) < sizeof (gpt_header)) {
+		kfree(gpt);
+                gpt=NULL;
+		return NULL;
+	}
+
+	return gpt;
+}
+
+/**
+ * is_gpt_valid() - tests one GPT header and PTEs for validity
+ * @hd
+ * @bdev
+ * @lba is the logical block address of the GPT header to test
+ * @gpt is a GPT header ptr, filled on return.
+ * @ptes is a 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 gendisk *hd, struct block_device *bdev, u64 lba,
+	     gpt_header **gpt, gpt_entry **ptes)
+{
+	u32 crc, origcrc;
+
+	if (!hd || !bdev || !gpt || !ptes)
+		return 0;
+	if (!(*gpt = alloc_read_gpt_header(hd, bdev, lba)))
+		return 0;
+
+	/* Check the GUID Partition Table signature */
+	if (le64_to_cpu((*gpt)->signature) != GPT_HEADER_SIGNATURE) {
+		Dprintk("GUID Partition Table Header signature is wrong: %"
+			PRIx64 " != %" PRIx64 "\n", le64_to_cpu((*gpt)->signature),
+			GPT_HEADER_SIGNATURE);
+		kfree(*gpt);
+		*gpt = NULL;
+		return 0;
+	}
+
+	/* 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) {
+		Dprintk
+		    ("GUID Partition Table Header CRC is wrong: %x != %x\n",
+		     crc, origcrc);
+		kfree(*gpt);
+		*gpt = NULL;
+		return 0;
+	}
+	(*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) {
+		Dprintk("GPT my_lba incorrect: %" PRIx64 " != %" PRIx64 "\n",
+			le64_to_cpu((*gpt)->my_lba), lba);
+		kfree(*gpt);
+		*gpt = NULL;
+		return 0;
+	}
+
+	if (!(*ptes = alloc_read_gpt_entries(hd, bdev, *gpt))) {
+		kfree(*gpt);
+		*gpt = NULL;
+		return 0;
+	}
+
+	/* Check the GUID Partition Entry Array CRC */
+	crc = efi_crc32((const unsigned char *) (*ptes),
+			le32_to_cpu((*gpt)->num_partition_entries) *
+			le32_to_cpu((*gpt)->sizeof_partition_entry));
+
+	if (crc != le32_to_cpu((*gpt)->partition_entry_array_crc32)) {
+		Dprintk("GUID Partitition Entry Array CRC check failed.\n");
+		kfree(*gpt);
+		*gpt = NULL;
+		kfree(*ptes);
+		*ptes = NULL;
+		return 0;
+	}
+
+	/* We're done, all's well */
+	return 1;
+}
+
+/**
+ * compare_gpts() - Search disk for valid GPT headers and PTEs
+ * @pgpt is the primary GPT header
+ * @agpt is the alternate GPT header
+ * @lastlba is the 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)) {
+		printk(KERN_WARNING
+		       "GPT:Primary header LBA != Alt. header alternate_lba\n");
+		printk(KERN_WARNING "GPT:%" PRIx64 " != %" PRIx64 "\n",
+		       le64_to_cpu(pgpt->my_lba),
+                       le64_to_cpu(agpt->alternate_lba));
+		error_found++;
+	}
+	if (le64_to_cpu(pgpt->alternate_lba) != le64_to_cpu(agpt->my_lba)) {
+		printk(KERN_WARNING
+		       "GPT:Primary header alternate_lba != Alt. header my_lba\n");
+		printk(KERN_WARNING "GPT:%" PRIx64 " != %" PRIx64 "\n",
+		       le64_to_cpu(pgpt->alternate_lba),
+                       le64_to_cpu(agpt->my_lba));
+		error_found++;
+	}
+	if (le64_to_cpu(pgpt->first_usable_lba) !=
+            le64_to_cpu(agpt->first_usable_lba)) {
+		printk(KERN_WARNING "GPT:first_usable_lbas don't match.\n");
+		printk(KERN_WARNING "GPT:%" PRIx64 " != %" PRIx64 "\n",
+		       le64_to_cpu(pgpt->first_usable_lba),
+                       le64_to_cpu(agpt->first_usable_lba));
+		error_found++;
+	}
+	if (le64_to_cpu(pgpt->last_usable_lba) !=
+            le64_to_cpu(agpt->last_usable_lba)) {
+		printk(KERN_WARNING "GPT:last_usable_lbas don't match.\n");
+		printk(KERN_WARNING "GPT:%" PRIx64 " != %" PRIx64 "\n",
+		       le64_to_cpu(pgpt->last_usable_lba),
+                       le64_to_cpu(agpt->last_usable_lba));
+		error_found++;
+	}
+	if (efi_guidcmp(pgpt->disk_guid, agpt->disk_guid)) {
+		printk(KERN_WARNING "GPT:disk_guids don't match.\n");
+		error_found++;
+	}
+	if (le32_to_cpu(pgpt->num_partition_entries) !=
+            le32_to_cpu(agpt->num_partition_entries)) {
+		printk(KERN_WARNING "GPT:num_partition_entries don't match: "
+		       "0x%x != 0x%x\n",
+		       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)) {
+		printk(KERN_WARNING
+		       "GPT:sizeof_partition_entry values don't match: "
+		       "0x%x != 0x%x\n",
+                       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)) {
+		printk(KERN_WARNING
+		       "GPT:partition_entry_array_crc32 values don't match: "
+		       "0x%x != 0x%x\n",
+                       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) {
+		printk(KERN_WARNING
+		       "GPT:Primary header thinks Alt. header is not at the end of the disk.\n");
+		printk(KERN_WARNING "GPT:%" PRIx64 " != %" PRIx64 "\n",
+		       le64_to_cpu(pgpt->alternate_lba), lastlba);
+		error_found++;
+	}
+
+	if (le64_to_cpu(agpt->my_lba) != lastlba) {
+		printk(KERN_WARNING
+		       "GPT:Alternate GPT header not at the end of the disk.\n");
+		printk(KERN_WARNING "GPT:%" PRIx64 " != %" PRIx64 "\n",
+		       le64_to_cpu(agpt->my_lba), lastlba);
+		error_found++;
+	}
+
+	if (error_found)
+		printk(KERN_WARNING
+		       "GPT: Use GNU Parted to correct GPT errors.\n");
+	return;
+}
+
+/**
+ * find_valid_gpt() - Search disk for valid GPT headers and PTEs
+ * @hd
+ * @bdev
+ * @gpt is a GPT header ptr, filled on return.
+ * @ptes is a 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 finding either the Primary GPT header and PTEs valid,
+ * or the Alternate GPT header and PTEs valid, and the PMBR valid.
+ */
+static int
+find_valid_gpt(struct gendisk *hd, struct block_device *bdev,
+	       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 = NULL;
+	u64 lastlba;
+	if (!hd || !bdev || !gpt || !ptes)
+		return 0;
+
+	lastlba = last_lba(hd, bdev);
+	good_pgpt = is_gpt_valid(hd, bdev, GPT_PRIMARY_PARTITION_TABLE_LBA,
+				 &pgpt, &pptes);
+        if (good_pgpt) {
+		good_agpt = is_gpt_valid(hd, bdev,
+                                         le64_to_cpu(pgpt->alternate_lba),
+					 &agpt, &aptes);
+                if (!good_agpt) {
+                        good_agpt = is_gpt_valid(hd, bdev, lastlba,
+                                                 &agpt, &aptes);
+                }
+        }
+        else {
+                good_agpt = is_gpt_valid(hd, bdev, lastlba,
+                                         &agpt, &aptes);
+        }
+
+        /* The obviously unsuccessful case */
+        if (!good_pgpt && !good_agpt) {
+                goto fail;
+        }
+
+	/* This will be added to the EFI Spec. per Intel after v1.02. */
+        legacymbr = kmalloc(sizeof (*legacymbr), GFP_KERNEL);
+        if (legacymbr) {
+                memset(legacymbr, 0, sizeof (*legacymbr));
+                read_lba(hd, bdev, 0, (u8 *) legacymbr,
+                         sizeof (*legacymbr));
+                good_pmbr = is_pmbr_valid(legacymbr);
+                kfree(legacymbr);
+                legacymbr=NULL;
+        }
+
+        /* Failure due to bad PMBR */
+        if ((good_pgpt || good_agpt) && !good_pmbr && !force_gpt) {
+                printk(KERN_WARNING 
+                       "  Warning: Disk has a valid GPT signature "
+                       "but invalid PMBR.\n");
+                printk(KERN_WARNING
+                       "  Assuming this disk is *not* a GPT disk anymore.\n");
+                printk(KERN_WARNING
+                       "  Use gpt kernel option to override.  "
+                       "Use GNU Parted to correct disk.\n");
+                goto fail;
+        }
+
+        /* Would fail due to bad PMBR, but force GPT anyhow */
+        if ((good_pgpt || good_agpt) && !good_pmbr && force_gpt) {
+                printk(KERN_WARNING
+                       "  Warning: Disk has a valid GPT signature but "
+                       "invalid PMBR.\n");
+                printk(KERN_WARNING
+                       "  Use GNU Parted to correct disk.\n");
+                printk(KERN_WARNING
+                       "  gpt option taken, disk treated as GPT.\n");
+        }
+
+        compare_gpts(pgpt, agpt, lastlba);
+
+        /* The good cases */
+        if (good_pgpt && (good_pmbr || force_gpt)) {
+                *gpt  = pgpt;
+                *ptes = pptes;
+                if (agpt)  { kfree(agpt);   agpt = NULL; }
+                if (aptes) { kfree(aptes); aptes = NULL; }
+                if (!good_agpt) {
+                        printk(KERN_WARNING 
+			       "Alternate GPT is invalid, "
+                               "using primary GPT.\n");
+                }
+                return 1;
+        }
+        else if (good_agpt && (good_pmbr || force_gpt)) {
+                *gpt  = agpt;
+                *ptes = aptes;
+                if (pgpt)  { kfree(pgpt);   pgpt = NULL; }
+                if (pptes) { kfree(pptes); pptes = NULL; }
+                printk(KERN_WARNING 
+                       "Primary GPT is invalid, using alternate GPT.\n");
+                return 1;
+        }
+
+ fail:
+        if (pgpt)  { kfree(pgpt);   pgpt=NULL; }
+        if (agpt)  { kfree(agpt);   agpt=NULL; }
+        if (pptes) { kfree(pptes); pptes=NULL; }
+        if (aptes) { kfree(aptes); aptes=NULL; }
+        *gpt = NULL;
+        *ptes = NULL;
+        return 0;
+}
+
+/**
+ * add_gpt_partitions(struct gendisk *hd, struct block_device *bdev,
+ * @hd
+ * @bdev
+ *
+ * Description: Create devices for each entry in the GUID Partition Table
+ * Entries.
+ *
+ * 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
+ *
+ */
+static int
+add_gpt_partitions(struct gendisk *hd, struct block_device *bdev, int nextminor)
+{
+	gpt_header *gpt = NULL;
+	gpt_entry *ptes = NULL;
+	u32 i;
+	int max_p; 
+
+	if (!hd || !bdev)
+		return -1;
+
+	if (!find_valid_gpt(hd, bdev, &gpt, &ptes) || !gpt || !ptes) {
+		if (gpt) {
+			kfree(gpt);
+                        gpt = NULL;
+                }
+		if (ptes) {
+			kfree(ptes);
+                        ptes = NULL;
+                }
+		return 0;
+	}
+
+	Dprintk("GUID Partition Table is valid!  Yea!\n");
+
+	max_p = (1 << hd->minor_shift) - 1;
+	for (i = 0; i < le32_to_cpu(gpt->num_partition_entries) && i < max_p; i++) {
+		if (!efi_guidcmp(ptes[i].partition_type_guid, NULL_GUID))
+			continue;
+
+		add_gd_partition(hd, nextminor+i,
+                                 le64_to_cpu(ptes[i].starting_lba),
+				 (le64_to_cpu(ptes[i].ending_lba) -
+                                  le64_to_cpu(ptes[i].starting_lba) +
+				  1));
+
+		/* If there's this is a RAID volume, tell md */
+#if CONFIG_BLK_DEV_MD
+		if (!efi_guidcmp(ptes[i].partition_type_guid,
+                                 PARTITION_LINUX_RAID_GUID)) {
+                        md_autodetect_dev(MKDEV
+                                          (MAJOR(to_kdev_t(bdev->bd_dev)),
+                                           nextminor+i));
+		}
+#endif
+	}
+	kfree(ptes);
+        ptes=NULL;
+	kfree(gpt);
+        gpt=NULL;
+	printk("\n");
+	return 1;
+}
+
+/**
+ * efi_partition(): EFI GPT partition handling entry function
+ * @hd
+ * @bdev
+ * @first_sector: unused
+ * @first_part_minor: minor number assigned to first GPT partition found
+ *
+ * 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.
+ *
+ * set_blocksize() calls are necessary to be able to read
+ * a disk with an odd number of 512-byte sectors, as the
+ * default BLOCK_SIZE of 1024 bytes won't let that last
+ * sector be read otherwise.
+ *
+ * Returns:
+ * -1 if unable to read the partition table
+ *  0 if this isn't our partitoin table
+ *  1 if successful
+ */
+int
+efi_partition(struct gendisk *hd, struct block_device *bdev,
+	      unsigned long first_sector, int first_part_minor)
+{
+
+	kdev_t dev = to_kdev_t(bdev->bd_dev);
+	int hardblocksize = get_hardsect_size(dev);
+	int orig_blksize_size = BLOCK_SIZE;
+	int rc = 0;
+
+	/* Need to change the block size that the block layer uses */
+	if (blksize_size[MAJOR(dev)]) {
+                orig_blksize_size = blksize_size[MAJOR(dev)][MINOR(dev)];
+	}
+
+	if (orig_blksize_size != hardblocksize)
+		set_blocksize(dev, hardblocksize);
+
+	rc = add_gpt_partitions(hd, bdev, first_part_minor);
+
+	/* change back */
+	if (orig_blksize_size != hardblocksize)
+		set_blocksize(dev, orig_blksize_size);
+
+	return rc;
+}

FUNET's LINUX-ADM group, linux-adm@nic.funet.fi
TCL-scripts by Sam Shen (who was at: slshen@lbl.gov)