[PATCH] EFI GUID partition table support.

EFI GUID partition table support from Matt Domsch

Documentation/kernel-parameters.txt

@@ -17,6 +17,7 @@ restrictions referred to are that the relevant option is valid if:
 	CD	Appropriate CD support is enabled.
 	DEVFS   devfs support is enabled. 
 	DRM	Direct Rendering Management support is enabled. 
+	EFI	EFI Partitioning (GPT) is enabled
 	EIDE	EIDE/ATAPI support is enabled.
 	FB	The frame buffer device is enabled.
 	HW	Appropriate hardware is enabled.
@@ -219,6 +220,9 @@ running once the system is up.
  
 	gdth=		[HW,SCSI]
 
+	gpt             [EFI] Forces disk with valid GPT signature but
+			invalid Protective MBR to be treated as GPT.
+
 	gscd=		[HW,CD]
 
 	gus=		[HW,SOUND] 

fs/partitions/Config.help

@@ -115,6 +115,11 @@ CONFIG_SGI_PARTITION
   Say Y here if you would like to be able to read the hard disk
   partition table format used by SGI machines.
 
+CONFIG_EFI_PARTITION
+  Say Y here if you would like to use hard disks under Linux which
+  were partitioned using EFI GPT.  Presently only useful on the
+  IA-64 platform.
+
 CONFIG_ULTRIX_PARTITION
   Say Y here if you would like to be able to read the hard disk
   partition table format used by DEC (now Compaq) Ultrix machines.

fs/partitions/Config.in

@@ -32,6 +32,7 @@ if [ "$CONFIG_PARTITION_ADVANCED" = "y" ]; then
    bool '  SGI partition support' CONFIG_SGI_PARTITION
    bool '  Ultrix partition table support' CONFIG_ULTRIX_PARTITION
    bool '  Sun partition tables support' CONFIG_SUN_PARTITION
+   bool '  EFI GUID Partition support' CONFIG_EFI_PARTITION
 else
    if [ "$ARCH" = "alpha" ]; then
       define_bool CONFIG_OSF_PARTITION y

fs/partitions/Makefile

@@ -24,6 +24,7 @@ obj-$(CONFIG_SGI_PARTITION) += sgi.o
 obj-$(CONFIG_SUN_PARTITION) += sun.o
 obj-$(CONFIG_ULTRIX_PARTITION) += ultrix.o
 obj-$(CONFIG_IBM_PARTITION) += ibm.o
+obj-$(CONFIG_EFI_PARTITION) += efi.o
 
 include $(TOPDIR)/Rules.make
 

fs/partitions/check.c

@@ -35,6 +35,7 @@
 #include "sun.h"
 #include "ibm.h"
 #include "ultrix.h"
+#include "efi.h"
 
 int warn_no_part = 1; /*This is ugly: should make genhd removable media aware*/
 
@@ -43,6 +44,9 @@ static int (*check_part[])(struct gendisk *hd, struct block_device *bdev,
 #ifdef CONFIG_ACORN_PARTITION
 	acorn_partition,
 #endif
+#ifdef CONFIG_EFI_PARTITION
+	efi_partition,		/* this must come before msdos */
+#endif
 #ifdef CONFIG_LDM_PARTITION
 	ldm_partition,		/* this must come before msdos */
 #endif

fs/partitions/efi.c

+/************************************************************
+ * 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:
+ * 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 <linux/crc32.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"
+#  define __PRIPTR_PREFIX	"l"
+# else
+#  define __PRI64_PREFIX	"ll"
+#  define __PRIPTR_PREFIX
+# 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 forcegpt;
+static int __init
+force_gpt(char *str)
+{
+	forcegpt = 1;
+	return 1;
+}
+
+__setup("gpt", force_gpt);
+
+/**
+ * le_efi_guid_to_cpus()
+ * @guid
+ *
+ * Description: modifies @guid in situ
+ *
+ * This function converts a little endian efi_guid_t to the
+ * native cpu representation.  The EFI Spec. declares that all 
+ * on-disk structures are stored in little endian format.
+ */
+static void
+le_efi_guid_to_cpus(efi_guid_t *guid)
+{
+	le32_to_cpus(guid->data1);
+	le16_to_cpus(guid->data2);
+	le16_to_cpus(guid->data3);
+	/* no need to change the rest. It's already an array of chars */
+	return;
+}
+
+/**
+ * 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);
+}
+
+/**
+ * le_part_attributes_to_cpus(): converts LE attributes to CPU type in situ
+ * @attributes - ptr to partition attributes
+ * 
+ * Description:  modifies attributes in situ, returns nothing.
+ * Converts a little endian partition attributes struct to the
+ * native cpu representation.  Good for reading attributes off of a disk.
+ */
+static void
+le_part_attributes_to_cpus(gpt_entry_attributes * a)
+{
+	u64 *b = (u64 *) a;
+	*b = le64_to_cpu(*b);
+}
+
+/**
+ * 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;
+}
+
+/**
+ * print_gpt_header(): unparses gpt header to console
+ * @gpt: gpt header
+ */
+static void
+print_gpt_header(gpt_header *gpt)
+{
+	Dprintk("GUID Partition Table Header\n");
+	if (!gpt)
+		return;
+	Dprintk("signature                   : %" PRIx64 "\n", gpt->signature);
+	Dprintk("revision                    : %x\n", gpt->revision);
+	Dprintk("header_size                 : %x\n", gpt->header_size);
+	Dprintk("header_crc32                : %x\n", gpt->header_crc32);
+	Dprintk("my_lba                      : %" PRIx64 "\n", gpt->my_lba);
+	Dprintk("alternate_lba               : %" PRIx64 "\n",
+		gpt->alternate_lba);
+	Dprintk("first_usable_lba            : %" PRIx64 "\n",
+		gpt->first_usable_lba);
+	Dprintk("last_usable_lba             : %" PRIx64 "\n",
+		gpt->last_usable_lba);
+	Dprintk("partition_entry_lba         : %" PRIx64 "\n",
+		gpt->partition_entry_lba);
+	Dprintk("num_partition_entries       : %x\n",
+		gpt->num_partition_entries);
+	Dprintk("sizeof_partition_entry      : %x\n",
+		gpt->sizeof_partition_entry);
+	Dprintk("partition_entry_array_crc32 : %x\n",
+		gpt->partition_entry_array_crc32);
+	return;
+}
+
+/**
+ * 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)
+{
+	u32 i, j;
+	size_t count;
+	gpt_entry *pte;
+	if (!hd || !bdev || !gpt)
+		return NULL;
+
+	count = gpt->num_partition_entries * 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, gpt->partition_entry_lba, (u8 *) pte,
+		     count) < count) {
+		kfree(pte);
+		return NULL;
+	}
+	/* Fixup endianness */
+	for (i = 0; i < gpt->num_partition_entries; i++) {
+		le_efi_guid_to_cpus(&pte[i].partition_type_guid);
+		le_efi_guid_to_cpus(&pte[i].unique_partition_guid);
+		le64_to_cpus(pte[i].starting_lba);
+		le64_to_cpus(pte[i].ending_lba);
+		le_part_attributes_to_cpus(&pte[i].attributes);
+		for (j = 0; j < (72 / sizeof (efi_char16_t)); j++) {
+			le16_to_cpus((u16) (pte[i].partition_name[j]));
+		}
+	}
+
+	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);
+		return NULL;
+	}
+
+	/* Fixup endianness */
+	le64_to_cpus(gpt->signature);
+	le32_to_cpus(gpt->revision);
+	le32_to_cpus(gpt->header_size);
+	le32_to_cpus(gpt->header_crc32);
+	le32_to_cpus(gpt->reserved1);
+	le64_to_cpus(gpt->my_lba);
+	le64_to_cpus(gpt->alternate_lba);
+	le64_to_cpus(gpt->first_usable_lba);
+	le64_to_cpus(gpt->last_usable_lba);
+	le_efi_guid_to_cpus(&gpt->disk_guid);
+	le64_to_cpus(gpt->partition_entry_lba);
+	le32_to_cpus(gpt->num_partition_entries);
+	le32_to_cpus(gpt->sizeof_partition_entry);
+	le32_to_cpus(gpt->partition_entry_array_crc32);
+
+	print_gpt_header(gpt);
+
+	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 ((*gpt)->signature != GPT_HEADER_SIGNATURE) {
+		Dprintk("GUID Partition Table Header signature is wrong: %"
+			PRIx64 " != %" PRIx64 "\n", (*gpt)->signature,
+			GPT_HEADER_SIGNATURE);
+		kfree(*gpt);
+		*gpt = NULL;
+		return 0;
+	}
+
+	/* Check the GUID Partition Table CRC */
+	origcrc = (*gpt)->header_crc32;
+	(*gpt)->header_crc32 = 0;
+	crc = efi_crc32((const unsigned char *) (*gpt), (*gpt)->header_size);
+
+	if (crc != origcrc) {
+		Dprintk
+		    ("GUID Partition Table Header CRC is wrong: %x != %x\n",
+		     (*gpt)->header_crc32, origcrc);
+		kfree(*gpt);
+		*gpt = NULL;
+		return 0;
+	}
+	(*gpt)->header_crc32 = origcrc;
+
+	/* Check that the my_lba entry points to the LBA that contains
+	 * the GUID Partition Table */
+	if ((*gpt)->my_lba != lba) {
+		Dprintk("GPT my_lba incorrect: %" PRIx64 " != %" PRIx64 "\n",
+			(*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),
+			(*gpt)->num_partition_entries *
+			(*gpt)->sizeof_partition_entry);
+
+	if (crc != (*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 (pgpt->my_lba != agpt->alternate_lba) {
+		printk(KERN_WARNING
+		       "GPT:Primary header LBA != Alt. header alternate_lba\n");
+		printk(KERN_WARNING "GPT:%" PRIx64 " != %" PRIx64 "\n",
+		       pgpt->my_lba, agpt->alternate_lba);
+		error_found++;
+	}
+	if (pgpt->alternate_lba != agpt->my_lba) {
+		printk(KERN_WARNING
+		       "GPT:Primary header alternate_lba != Alt. header my_lba\n");
+		printk(KERN_WARNING "GPT:%" PRIx64 " != %" PRIx64 "\n",
+		       pgpt->alternate_lba, agpt->my_lba);
+		error_found++;
+	}
+	if (pgpt->first_usable_lba != agpt->first_usable_lba) {
+		printk(KERN_WARNING "GPT:first_usable_lbas don't match.\n");
+		printk(KERN_WARNING "GPT:%" PRIx64 " != %" PRIx64 "\n",
+		       pgpt->first_usable_lba, agpt->first_usable_lba);
+		error_found++;
+	}
+	if (pgpt->last_usable_lba != agpt->last_usable_lba) {
+		printk(KERN_WARNING "GPT:last_usable_lbas don't match.\n");
+		printk(KERN_WARNING "GPT:%" PRIx64 " != %" PRIx64 "\n",
+		       pgpt->last_usable_lba, 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 (pgpt->num_partition_entries != agpt->num_partition_entries) {
+		printk(KERN_WARNING "GPT:num_partition_entries don't match: "
+		       "0x%x != 0x%x\n",
+		       pgpt->num_partition_entries,
+		       agpt->num_partition_entries);
+		error_found++;
+	}
+	if (pgpt->sizeof_partition_entry != agpt->sizeof_partition_entry) {
+		printk(KERN_WARNING
+		       "GPT:sizeof_partition_entry values don't match: "
+		       "0x%x != 0x%x\n", pgpt->sizeof_partition_entry,
+		       agpt->sizeof_partition_entry);
+		error_found++;
+	}
+	if (pgpt->partition_entry_array_crc32 !=
+	    agpt->partition_entry_array_crc32) {
+		printk(KERN_WARNING
+		       "GPT:partition_entry_array_crc32 values don't match: "
+		       "0x%x != 0x%x\n", pgpt->partition_entry_array_crc32,
+		       agpt->partition_entry_array_crc32);
+		error_found++;
+	}
+	if (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",
+		       pgpt->alternate_lba, lastlba);
+		error_found++;
+	}
+
+	if (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",
+		       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);
+	/* Check the Primary GPT */
+	good_pgpt = is_gpt_valid(hd, bdev, GPT_PRIMARY_PARTITION_TABLE_LBA,
+				 &pgpt, &pptes);
+	if (good_pgpt) {
+		/* Primary GPT is OK, check the alternate and warn if bad */
+		good_agpt = is_gpt_valid(hd, bdev, pgpt->alternate_lba,
+					 &agpt, &aptes);
+		if (!good_agpt) {
+			printk(KERN_WARNING
+			       "Alternate GPT is invalid, using primary GPT.\n");
+		}
+
+		compare_gpts(pgpt, agpt, lastlba);
+
+		*gpt = pgpt;
+		*ptes = pptes;
+		if (agpt) {
+			kfree(agpt);
+			agpt = NULL;
+		}
+		if (aptes) {
+			kfree(aptes);
+			aptes = NULL;
+		}
+	} /* if primary is valid */
+	else {
+		/* Primary GPT is bad, check the Alternate GPT */
+		good_agpt = is_gpt_valid(hd, bdev, lastlba, &agpt, &aptes);
+		if (good_agpt) {
+			/* Primary is bad, alternate is good.
+			   Return values from the alternate and warn.
+			 */
+			printk(KERN_WARNING
+			       "Primary GPT is invalid, using alternate GPT.\n");
+			*gpt = agpt;
+			*ptes = aptes;
+		}
+	}
+
+	/* Now test for valid PMBR */
+	/* This will be added to the EFI Spec. per Intel after v1.02. */
+	if (good_pgpt || good_agpt) {
+		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);
+		}
+		if (good_pmbr)
+			return 1;
+		if (!forcegpt) {
+			printk
+			    (" 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");
+		} else {
+			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");
+			return 1;
+		}
+	}
+
+	/* Both primary and alternate GPTs are bad, and/or PMBR is invalid.
+	 * This isn't our disk, return 0.
+	 */
+	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, nummade = 0;
+	int max_p; 
+
+	efi_guid_t unusedGuid = UNUSED_ENTRY_GUID;
+#if CONFIG_BLK_DEV_MD
+	efi_guid_t raidGuid = PARTITION_LINUX_RAID_GUID;
+#endif
+
+	if (!hd || !bdev)
+		return -1;
+
+	if (!find_valid_gpt(hd, bdev, &gpt, &ptes) || !gpt || !ptes) {
+		if (gpt)
+			kfree(gpt);
+		if (ptes)
+			kfree(ptes);
+		return 0;
+	}
+
+	Dprintk("GUID Partition Table is valid!  Yea!\n");
+
+	max_p = (1 << hd->minor_shift) - 1;
+	for (i = 0; i < gpt->num_partition_entries && nummade < max_p; i++) {
+		if (!efi_guidcmp(unusedGuid, ptes[i].partition_type_guid))
+			continue;
+
+		add_gd_partition(hd, nextminor, ptes[i].starting_lba,
+				 (ptes[i].ending_lba - ptes[i].starting_lba +
+				  1));
+
+		/* If there's this is a RAID volume, tell md */
+#if CONFIG_BLK_DEV_MD
+		if (!efi_guidcmp(raidGuid, ptes[i].partition_type_guid)) {
+			md_autodetect_dev(mk_kdev(hd->major,
+                                                  nextminor));
+		}
+#endif
+		nummade++;
+		nextminor++;
+
+	}
+	kfree(ptes);
+	kfree(gpt);
+	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;
+}
+
+/*
+ * Overrides for Emacs so that we follow Linus's tabbing style.
+ * Emacs will notice this stuff at the end of the file and automatically
+ * adjust the settings for this buffer only.  This must remain at the end
+ * of the file.
+ * ---------------------------------------------------------------------------
+ * Local variables:
+ * c-indent-level: 4
+ * c-brace-imaginary-offset: 0
+ * c-brace-offset: -4
+ * c-argdecl-indent: 4
+ * c-label-offset: -4
+ * c-continued-statement-offset: 4
+ * c-continued-brace-offset: 0
+ * indent-tabs-mode: nil
+ * tab-width: 8
+ * End:
+ */

fs/partitions/efi.h

+/************************************************************
+ * EFI GUID Partition Table
+ * Per Intel EFI Specification v1.02
+ * http://developer.intel.com/technology/efi/efi.htm
+ *
+ * By Matt Domsch <Matt_Domsch@dell.com>  Fri Sep 22 22:15:56 CDT 2000  
+ *   Copyright 2000,2001 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
+ * 
+ ************************************************************/
+
+#ifndef FS_PART_EFI_H_INCLUDED
+#define FS_PART_EFI_H_INCLUDED
+
+#include <linux/types.h>
+#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>
+/*
+ * Yes, specifying asm-ia64 is ugly, but this lets it build on
+ * other platforms too, until efi.h moves to include/linux.
+ */
+#include <asm-ia64/efi.h>
+
+#define MSDOS_MBR_SIGNATURE 0xaa55
+#define EFI_PMBR_OSTYPE_EFI 0xEF
+#define EFI_PMBR_OSTYPE_EFI_GPT 0xEE
+
+#define GPT_BLOCK_SIZE 512
+#define GPT_HEADER_SIGNATURE 0x5452415020494645L
+#define GPT_HEADER_REVISION_V1 0x00010000
+#define GPT_PRIMARY_PARTITION_TABLE_LBA 1
+
+#define UNUSED_ENTRY_GUID    \
+    ((efi_guid_t) { 0x00000000, 0x0000, 0x0000, { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }})
+#define PARTITION_SYSTEM_GUID \
+((efi_guid_t) { 0xC12A7328, 0xF81F, 0x11d2, { 0xBA, 0x4B, 0x00, 0xA0, 0xC9, 0x3E, 0xC9, 0x3B }})
+#define LEGACY_MBR_PARTITION_GUID \
+    ((efi_guid_t) { 0x024DEE41, 0x33E7, 0x11d3, { 0x9D, 0x69, 0x00, 0x08, 0xC7, 0x81, 0xF3, 0x9F }})
+#define PARTITION_MSFT_RESERVED_GUID \
+    ((efi_guid_t) { 0xE3C9E316, 0x0B5C, 0x4DB8, { 0x81, 0x7D, 0xF9, 0x2D, 0xF0, 0x02, 0x15, 0xAE }})
+#define PARTITION_BASIC_DATA_GUID \
+    ((efi_guid_t) { 0xEBD0A0A2, 0xB9E5, 0x4433, { 0x87, 0xC0, 0x68, 0xB6, 0xB7, 0x26, 0x99, 0xC7 }})
+#define PARTITION_LINUX_RAID_GUID \
+    ((efi_guid_t) { 0xa19d880f, 0x05fc, 0x4d3b, { 0xa0, 0x06, 0x74, 0x3f, 0x0f, 0x84, 0x91, 0x1e  }})
+#define PARTITION_LINUX_SWAP_GUID \
+    ((efi_guid_t) { 0x0657fd6d, 0xa4ab, 0x43c4, { 0x84, 0xe5, 0x09, 0x33, 0xc8, 0x4b, 0x4f, 0x4f  }})
+#define PARTITION_LINUX_LVM_GUID \
+    ((efi_guid_t) { 0xe6d6d379, 0xf507, 0x44c2, { 0xa2, 0x3c, 0x23, 0x8f, 0x2a, 0x3d, 0xf9, 0x28 }})
+
+typedef struct _gpt_header {
+	u64 signature;
+	u32 revision;
+	u32 header_size;
+	u32 header_crc32;
+	u32 reserved1;
+	u64 my_lba;
+	u64 alternate_lba;
+	u64 first_usable_lba;
+	u64 last_usable_lba;
+	efi_guid_t disk_guid;
+	u64 partition_entry_lba;
+	u32 num_partition_entries;
+	u32 sizeof_partition_entry;
+	u32 partition_entry_array_crc32;
+	u8 reserved2[GPT_BLOCK_SIZE - 92];
+} __attribute__ ((packed)) gpt_header;
+
+typedef struct _gpt_entry_attributes {
+	u64 required_to_function:1;
+	u64 reserved:47;
+        u64 type_guid_specific:16;
+} __attribute__ ((packed)) gpt_entry_attributes;
+
+typedef struct _gpt_entry {
+	efi_guid_t partition_type_guid;
+	efi_guid_t unique_partition_guid;
+	u64 starting_lba;
+	u64 ending_lba;
+	gpt_entry_attributes attributes;
+	efi_char16_t partition_name[72 / sizeof (efi_char16_t)];
+} __attribute__ ((packed)) gpt_entry;
+
+typedef struct _legacy_mbr {
+	u8 boot_code[440];
+	u32 unique_mbr_signature;
+	u16 unknown;
+	struct partition partition_record[4];
+	u16 signature;
+} __attribute__ ((packed)) legacy_mbr;
+
+/* Functions */
+extern int
+ efi_partition(struct gendisk *hd, struct block_device *bdev,
+	      unsigned long first_sector, int first_part_minor);
+
+#endif
+
+/*
+ * Overrides for Emacs so that we follow Linus's tabbing style.
+ * Emacs will notice this stuff at the end of the file and automatically
+ * adjust the settings for this buffer only.  This must remain at the end
+ * of the file.
+ * --------------------------------------------------------------------------
+ * Local variables:
+ * c-indent-level: 4 
+ * c-brace-imaginary-offset: 0
+ * c-brace-offset: -4
+ * c-argdecl-indent: 4
+ * c-label-offset: -4
+ * c-continued-statement-offset: 4
+ * c-continued-brace-offset: 0
+ * indent-tabs-mode: nil
+ * tab-width: 8
+ * End:
+ */

fs/partitions/msdos.c

@@ -41,6 +41,7 @@ EXPORT_SYMBOL(ide_xlate_1024_hook);
 
 #include "check.h"
 #include "msdos.h"
+#include "efi.h"
 
 #if CONFIG_BLK_DEV_MD
 extern void md_autodetect_dev(kdev_t dev);
@@ -536,6 +537,16 @@ int msdos_partition(struct gendisk *hd, struct block_device *bdev,
 		return 0;
 	}
 	p = (struct partition *) (data + 0x1be);
+#ifdef CONFIG_EFI_PARTITION
+	for (i=1 ; i<=4 ; i++,p++) {
+		/* If this is an EFI GPT disk, msdos should ignore it. */
+		if (SYS_IND(p) == EFI_PMBR_OSTYPE_EFI_GPT) {
+			put_dev_sector(sect);
+			return 0;
+		}
+	}
+	p = (struct partition *) (data + 0x1be);
+#endif
 
 	/*
 	 * Look for partitions in two passes: