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- // SPDX-License-Identifier: GPL-2.0
- /*
- * fs/partitions/amiga.c
- *
- * Code extracted from drivers/block/genhd.c
- *
- * Copyright (C) 1991-1998 Linus Torvalds
- * Re-organised Feb 1998 Russell King
- */
- #define pr_fmt(fmt) fmt
- #include <linux/types.h>
- #include <linux/mm_types.h>
- #include <linux/overflow.h>
- #include <linux/affs_hardblocks.h>
- #include "check.h"
- /* magic offsets in partition DosEnvVec */
- #define NR_HD 3
- #define NR_SECT 5
- #define LO_CYL 9
- #define HI_CYL 10
- static __inline__ u32
- checksum_block(__be32 *m, int size)
- {
- u32 sum = 0;
- while (size--)
- sum += be32_to_cpu(*m++);
- return sum;
- }
- int amiga_partition(struct parsed_partitions *state)
- {
- Sector sect;
- unsigned char *data;
- struct RigidDiskBlock *rdb;
- struct PartitionBlock *pb;
- u64 start_sect, nr_sects;
- sector_t blk, end_sect;
- u32 cylblk; /* rdb_CylBlocks = nr_heads*sect_per_track */
- u32 nr_hd, nr_sect, lo_cyl, hi_cyl;
- int part, res = 0;
- unsigned int blksize = 1; /* Multiplier for disk block size */
- int slot = 1;
- for (blk = 0; ; blk++, put_dev_sector(sect)) {
- if (blk == RDB_ALLOCATION_LIMIT)
- goto rdb_done;
- data = read_part_sector(state, blk, §);
- if (!data) {
- pr_err("Dev %s: unable to read RDB block %llu\n",
- state->disk->disk_name, blk);
- res = -1;
- goto rdb_done;
- }
- if (*(__be32 *)data != cpu_to_be32(IDNAME_RIGIDDISK))
- continue;
- rdb = (struct RigidDiskBlock *)data;
- if (checksum_block((__be32 *)data, be32_to_cpu(rdb->rdb_SummedLongs) & 0x7F) == 0)
- break;
- /* Try again with 0xdc..0xdf zeroed, Windows might have
- * trashed it.
- */
- *(__be32 *)(data+0xdc) = 0;
- if (checksum_block((__be32 *)data,
- be32_to_cpu(rdb->rdb_SummedLongs) & 0x7F)==0) {
- pr_err("Trashed word at 0xd0 in block %llu ignored in checksum calculation\n",
- blk);
- break;
- }
- pr_err("Dev %s: RDB in block %llu has bad checksum\n",
- state->disk->disk_name, blk);
- }
- /* blksize is blocks per 512 byte standard block */
- blksize = be32_to_cpu( rdb->rdb_BlockBytes ) / 512;
- {
- char tmp[7 + 10 + 1 + 1];
- /* Be more informative */
- snprintf(tmp, sizeof(tmp), " RDSK (%d)", blksize * 512);
- strlcat(state->pp_buf, tmp, PAGE_SIZE);
- }
- blk = be32_to_cpu(rdb->rdb_PartitionList);
- put_dev_sector(sect);
- for (part = 1; (s32) blk>0 && part<=16; part++, put_dev_sector(sect)) {
- /* Read in terms partition table understands */
- if (check_mul_overflow(blk, (sector_t) blksize, &blk)) {
- pr_err("Dev %s: overflow calculating partition block %llu! Skipping partitions %u and beyond\n",
- state->disk->disk_name, blk, part);
- break;
- }
- data = read_part_sector(state, blk, §);
- if (!data) {
- pr_err("Dev %s: unable to read partition block %llu\n",
- state->disk->disk_name, blk);
- res = -1;
- goto rdb_done;
- }
- pb = (struct PartitionBlock *)data;
- blk = be32_to_cpu(pb->pb_Next);
- if (pb->pb_ID != cpu_to_be32(IDNAME_PARTITION))
- continue;
- if (checksum_block((__be32 *)pb, be32_to_cpu(pb->pb_SummedLongs) & 0x7F) != 0 )
- continue;
- /* RDB gives us more than enough rope to hang ourselves with,
- * many times over (2^128 bytes if all fields max out).
- * Some careful checks are in order, so check for potential
- * overflows.
- * We are multiplying four 32 bit numbers to one sector_t!
- */
- nr_hd = be32_to_cpu(pb->pb_Environment[NR_HD]);
- nr_sect = be32_to_cpu(pb->pb_Environment[NR_SECT]);
- /* CylBlocks is total number of blocks per cylinder */
- if (check_mul_overflow(nr_hd, nr_sect, &cylblk)) {
- pr_err("Dev %s: heads*sects %u overflows u32, skipping partition!\n",
- state->disk->disk_name, cylblk);
- continue;
- }
- /* check for consistency with RDB defined CylBlocks */
- if (cylblk > be32_to_cpu(rdb->rdb_CylBlocks)) {
- pr_warn("Dev %s: cylblk %u > rdb_CylBlocks %u!\n",
- state->disk->disk_name, cylblk,
- be32_to_cpu(rdb->rdb_CylBlocks));
- }
- /* RDB allows for variable logical block size -
- * normalize to 512 byte blocks and check result.
- */
- if (check_mul_overflow(cylblk, blksize, &cylblk)) {
- pr_err("Dev %s: partition %u bytes per cyl. overflows u32, skipping partition!\n",
- state->disk->disk_name, part);
- continue;
- }
- /* Calculate partition start and end. Limit of 32 bit on cylblk
- * guarantees no overflow occurs if LBD support is enabled.
- */
- lo_cyl = be32_to_cpu(pb->pb_Environment[LO_CYL]);
- start_sect = ((u64) lo_cyl * cylblk);
- hi_cyl = be32_to_cpu(pb->pb_Environment[HI_CYL]);
- nr_sects = (((u64) hi_cyl - lo_cyl + 1) * cylblk);
- if (!nr_sects)
- continue;
- /* Warn user if partition end overflows u32 (AmigaDOS limit) */
- if ((start_sect + nr_sects) > UINT_MAX) {
- pr_warn("Dev %s: partition %u (%llu-%llu) needs 64 bit device support!\n",
- state->disk->disk_name, part,
- start_sect, start_sect + nr_sects);
- }
- if (check_add_overflow(start_sect, nr_sects, &end_sect)) {
- pr_err("Dev %s: partition %u (%llu-%llu) needs LBD device support, skipping partition!\n",
- state->disk->disk_name, part,
- start_sect, end_sect);
- continue;
- }
- /* Tell Kernel about it */
- put_partition(state,slot++,start_sect,nr_sects);
- {
- /* Be even more informative to aid mounting */
- char dostype[4];
- char tmp[42];
- __be32 *dt = (__be32 *)dostype;
- *dt = pb->pb_Environment[16];
- if (dostype[3] < ' ')
- snprintf(tmp, sizeof(tmp), " (%c%c%c^%c)",
- dostype[0], dostype[1],
- dostype[2], dostype[3] + '@' );
- else
- snprintf(tmp, sizeof(tmp), " (%c%c%c%c)",
- dostype[0], dostype[1],
- dostype[2], dostype[3]);
- strlcat(state->pp_buf, tmp, PAGE_SIZE);
- snprintf(tmp, sizeof(tmp), "(res %d spb %d)",
- be32_to_cpu(pb->pb_Environment[6]),
- be32_to_cpu(pb->pb_Environment[4]));
- strlcat(state->pp_buf, tmp, PAGE_SIZE);
- }
- res = 1;
- }
- strlcat(state->pp_buf, "\n", PAGE_SIZE);
- rdb_done:
- return res;
- }
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