/************************************************************ * EFI GUID Partition Table handling * Per Intel EFI Specification v1.02 * http://developer.intel.com/technology/efi/efi.htm * efi.[ch] by Matt Domsch * Copyright 2000,2001,2002,2004 Dell Inc. * * 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 Nov 09 2004 Matt Domsch * - 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 * - 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 * - Removed __PRIPTR_PREFIX - not being used * * Mon Jan 14 2002 Matt Domsch * - Ported to 2.5.2-pre11 + library crc32 patch Linus applied * * Thu Dec 6 2001 Matt Domsch * - 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 * - Removed CONFIG_DEVFS_VOLUMES_UUID code entirely per Martin Wilck * * Wed Oct 10 2001 Matt Domsch * - Changed function comments to DocBook style per Andreas Dilger suggestion. * * Mon Oct 08 2001 Matt Domsch * - 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 * - 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 * - added devfs volume UUID support (/dev/volumes/uuids) for * mounting file systems by the partition GUID. * * Tue Dec 5 2000 Matt Domsch * - Moved crc32() to linux/lib, added efi_crc32(). * * Thu Nov 30 2000 Matt Domsch * - Replaced Intel's CRC32 function with an equivalent * non-license-restricted version. * * Wed Oct 25 2000 Matt Domsch * - Fixed the last_lba() call to return the proper last block * * Thu Oct 12 2000 Matt Domsch * - Thanks to Andries Brouwer for his debugging assistance. * - Code works, detects all the partitions. * ************************************************************/ #include #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 (bdev->bd_inode->i_size >> 9) - 1ULL; } static inline int pmbr_part_valid(struct partition *part) { if (part->sys_ind == EFI_PMBR_OSTYPE_EFI_GPT && le32_to_cpu(part->start_sect) == 1UL) return 1; return 0; } /** * 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; if (!mbr || le16_to_cpu(mbr->signature) != MSDOS_MBR_SIGNATURE) return 0; for (i = 0; i < 4; i++) if (pmbr_part_valid(&mbr->partition_record[i])) return 1; return 0; } /** * read_lba(): Read bytes from disk, starting at given LBA * @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 block_device *bdev, u64 lba, u8 * buffer, size_t count) { size_t totalreadcount = 0; if (!bdev || !buffer || lba > last_lba(bdev)) return 0; while (count) { int copied = 512; Sector sect; unsigned char *data = read_dev_sector(bdev, lba++, §); 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 * @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 block_device *bdev, gpt_header *gpt) { size_t count; gpt_entry *pte; if (!bdev || !gpt) return NULL; count = le32_to_cpu(gpt->num_partition_entries) * le32_to_cpu(gpt->sizeof_partition_entry); if (!count) return NULL; pte = kzalloc(count, GFP_KERNEL); if (!pte) return NULL; if (read_lba(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 * @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 block_device *bdev, u64 lba) { gpt_header *gpt; if (!bdev) return NULL; gpt = kzalloc(sizeof (gpt_header), GFP_KERNEL); if (!gpt) return NULL; if (read_lba(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 * @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 block_device *bdev, u64 lba, gpt_header **gpt, gpt_entry **ptes) { u32 crc, origcrc; u64 lastlba; if (!bdev || !gpt || !ptes) return 0; if (!(*gpt = alloc_read_gpt_header(bdev, 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\n", (unsigned long long)le64_to_cpu((*gpt)->signature), (unsigned long long)GPT_HEADER_SIGNATURE); 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\n", 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\n", (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(bdev); if (le64_to_cpu((*gpt)->first_usable_lba) > lastlba) { pr_debug("GPT: first_usable_lba incorrect: %lld > %lld\n", (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\n", (unsigned long long)le64_to_cpu((*gpt)->last_usable_lba), (unsigned long long)lastlba); goto fail; } if (!(*ptes = alloc_read_gpt_entries(bdev, *gpt))) goto fail; /* 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)) { pr_debug("GUID Partitition Entry Array CRC check failed.\n"); 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 is the pte to check * @lastlba is 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 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:%lld != %lld\n", (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)) { printk(KERN_WARNING "GPT:Primary header alternate_lba != Alt. header my_lba\n"); printk(KERN_WARNING "GPT:%lld != %lld\n", (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)) { printk(KERN_WARNING "GPT:first_usable_lbas don't match.\n"); printk(KERN_WARNING "GPT:%lld != %lld\n", (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)) { printk(KERN_WARNING "GPT:last_usable_lbas don't match.\n"); printk(KERN_WARNING "GPT:%lld != %lld\n", (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)) { 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:%lld != %lld\n", (unsigned long long)le64_to_cpu(pgpt->alternate_lba), (unsigned long long)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:%lld != %lld\n", (unsigned long long)le64_to_cpu(agpt->my_lba), (unsigned long long)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 * @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 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 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; u64 lastlba; if (!bdev || !gpt || !ptes) return 0; lastlba = last_lba(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) { read_lba(bdev, 0, (u8 *) legacymbr, sizeof (*legacymbr)); good_pmbr = is_pmbr_valid(legacymbr); kfree(legacymbr); } if (!good_pmbr) goto fail; } good_pgpt = is_gpt_valid(bdev, GPT_PRIMARY_PARTITION_TABLE_LBA, &pgpt, &pptes); if (good_pgpt) good_agpt = is_gpt_valid(bdev, le64_to_cpu(pgpt->alternate_lba), &agpt, &aptes); if (!good_agpt && force_gpt) good_agpt = is_gpt_valid(bdev, 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) { printk(KERN_WARNING "Alternate GPT is invalid, " "using primary GPT.\n"); } return 1; } else if (good_agpt) { *gpt = agpt; *ptes = aptes; kfree(pgpt); kfree(pptes); printk(KERN_WARNING "Primary GPT is invalid, using alternate GPT.\n"); return 1; } fail: kfree(pgpt); kfree(agpt); kfree(pptes); kfree(aptes); *gpt = NULL; *ptes = NULL; return 0; } /** * efi_partition(struct parsed_partitions *state, struct block_device *bdev) * @state * @bdev * * 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, struct block_device *bdev) { gpt_header *gpt = NULL; gpt_entry *ptes = NULL; u32 i; if (!find_valid_gpt(bdev, &gpt, &ptes) || !gpt || !ptes) { kfree(gpt); kfree(ptes); return 0; } pr_debug("GUID Partition Table is valid! Yea!\n"); for (i = 0; i < le32_to_cpu(gpt->num_partition_entries) && i < state->limit-1; i++) { if (!is_pte_valid(&ptes[i], last_lba(bdev))) continue; put_partition(state, i+1, le64_to_cpu(ptes[i].starting_lba), (le64_to_cpu(ptes[i].ending_lba) - le64_to_cpu(ptes[i].starting_lba) + 1ULL)); /* 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 = 1; } kfree(ptes); kfree(gpt); printk("\n"); return 1; }