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author | Al Viro <viro@zeniv.linux.org.uk> | 2011-09-16 00:25:05 -0400 |
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committer | Al Viro <viro@zeniv.linux.org.uk> | 2012-01-03 22:54:06 -0500 |
commit | 9be96f3fd10187f185d84cf878cf032465bcced3 (patch) | |
tree | 432a430ed9e0cbe0c18916cd3c3992f09b3feb37 /block/partitions/efi.c | |
parent | 4752bc309b7604d507c973c7b7678ac2ce10a058 (diff) | |
download | linux-9be96f3fd10187f185d84cf878cf032465bcced3.tar.bz2 |
move fs/partitions to block/
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'block/partitions/efi.c')
-rw-r--r-- | block/partitions/efi.c | 675 |
1 files changed, 675 insertions, 0 deletions
diff --git a/block/partitions/efi.c b/block/partitions/efi.c new file mode 100644 index 000000000000..6296b403c67a --- /dev/null +++ b/block/partitions/efi.c @@ -0,0 +1,675 @@ +/************************************************************ + * 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. + * + * 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 <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/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(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 + * @state + * @lba + * @buffer + * @size_t + * + * 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++, §); + 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 + * @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 = 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(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 + * @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 @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 = kzalloc(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 + * @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 parsed_partitions *state, u64 lba, + gpt_header **gpt, gpt_entry **ptes) +{ + u32 crc, origcrc; + u64 lastlba; + + 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\n", + (unsigned long long)le64_to_cpu((*gpt)->signature), + (unsigned long long)GPT_HEADER_SIGNATURE); + goto fail; + } + + /* Check the GUID Partition Table header size */ + if (le32_to_cpu((*gpt)->header_size) > + bdev_logical_block_size(state->bdev)) { + pr_debug("GUID Partition Table Header size is wrong: %u > %u\n", + le32_to_cpu((*gpt)->header_size), + bdev_logical_block_size(state->bdev)); + 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(state->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; + } + + /* Check that sizeof_partition_entry has the correct value */ + if (le32_to_cpu((*gpt)->sizeof_partition_entry) != sizeof(gpt_entry)) { + pr_debug("GUID Partitition Entry Size check failed.\n"); + 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), + 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 + * @state + * @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 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; + 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) { + read_lba(state, 0, (u8 *) legacymbr, + sizeof (*legacymbr)); + good_pmbr = is_pmbr_valid(legacymbr); + kfree(legacymbr); + } + if (!good_pmbr) + goto fail; + } + + 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) { + 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) + * @state + * + * 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; + u8 unparsed_guid[37]; + + if (!find_valid_gpt(state, &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++) { + struct partition_meta_info *info; + unsigned label_count = 0; + 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; + /* Instead of doing a manual swap to big endian, reuse the + * common ASCII hex format as the interim. + */ + efi_guid_unparse(&ptes[i].unique_partition_guid, unparsed_guid); + part_pack_uuid(unparsed_guid, info->uuid); + + /* Naively convert UTF16-LE to 7 bits. */ + label_max = min(sizeof(info->volname) - 1, + sizeof(ptes[i].partition_name)); + info->volname[label_max] = 0; + while (label_count < label_max) { + u8 c = ptes[i].partition_name[label_count] & 0xff; + if (c && !isprint(c)) + c = '!'; + info->volname[label_count] = c; + label_count++; + } + state->parts[i + 1].has_info = true; + } + kfree(ptes); + kfree(gpt); + strlcat(state->pp_buf, "\n", PAGE_SIZE); + return 1; +} |