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-rw-r--r--block/partitions/amiga.c207
1 files changed, 207 insertions, 0 deletions
diff --git a/block/partitions/amiga.c b/block/partitions/amiga.c
new file mode 100644
index 000000000..a99ec7f1a
--- /dev/null
+++ b/block/partitions/amiga.c
@@ -0,0 +1,207 @@
+// 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;
+ char b[BDEVNAME_SIZE];
+
+ for (blk = 0; ; blk++, put_dev_sector(sect)) {
+ if (blk == RDB_ALLOCATION_LIMIT)
+ goto rdb_done;
+ data = read_part_sector(state, blk, &sect);
+ if (!data) {
+ pr_err("Dev %s: unable to read RDB block %llu\n",
+ bdevname(state->bdev, b), 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",
+ bdevname(state->bdev, b), 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",
+ bdevname(state->bdev, b), blk, part);
+ break;
+ }
+ data = read_part_sector(state, blk, &sect);
+ if (!data) {
+ pr_err("Dev %s: unable to read partition block %llu\n",
+ bdevname(state->bdev, b), 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",
+ bdevname(state->bdev, b), 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",
+ bdevname(state->bdev, b), 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",
+ bdevname(state->bdev, b), 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",
+ bdevname(state->bdev, b), 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",
+ bdevname(state->bdev, b), 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;
+}