/* $NetBSD: bad144.c,v 1.1 2026/07/03 21:27:40 thorpej Exp $ */ /*- * Copyright (c) 2026 The NetBSD Foundation, Inc. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. */ /* * Copyright (c) 1982, 1986, 1990, 1993 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * @(#)dkbad.c 8.2 (Berkeley) 1/12/94 */ #include <sys/cdefs.h> __KERNEL_RCSID(0, "$NetBSD: bad144.c,v 1.1 2026/07/03 21:27:40 thorpej Exp $"); #include <sys/param.h> #include <sys/buf.h> #include <sys/dkbad.h> #include <sys/errno.h> #include <sys/kmem.h> #include <sys/systm.h> /* * General description of DEC standard 144, from bad144(8): * * The format of the information is specified by DEC standard 144, as * follows. The bad sector information is located in the first 5 even * numbered sectors of the last track of the disk pack. There are five * identical copies of the information, described by the dkbad structure. * * Replacement sectors are allocated starting with the first sector before * the bad sector information and working backwards towards the beginning of * the disk. A maximum of 126 bad sectors are supported. The position of * the bad sector in the bad sector table determines the replacement sector * to which it corresponds. The bad sectors must be listed in ascending * order. * * (Additional commentary: this is not always true; some disk drivers may * use alternate cylinders for bad sector replacements. This is why we * do not perform the actual remapping here.) * * The bad sector information and replacement sectors are conventionally * only accessible through the ``c'' file system partition of the disk. If * that partition is used for a file system, the user is responsible for * making sure that it does not overlap the bad sector information or any * replacement sectors. Thus, one track plus 126 sectors must be reserved * to allow use of all of the possible bad sector replacements. * * NOTE ABOUT BYTE ORDER: You would think that because this on-disk format * originated at DEC that the fields would be nominally stored in little- * endian byte order, and in historical BSD usage (including 386BSD back * in the day), that held true. HOWEVER, bad144 is also used by the Xylogics * disk drivers, on Sun3 and SPARC systems which are big-endian and those * drivers historically did NOT byte-swap the entries in the table (this also * seems to be consistent with how SunOS versions that supported SMD drives * also treated bad144). So, we have ended up with a mixed bag, and I have * no interest in disturbing that particular sleeping dog. */ struct bad144_context { /* Provided by bad144 client at setup time. */ uint32_t bc_secsize; /* drive sector size */ uint32_t bc_ncyl; /* drive data cylinders */ uint32_t bc_ntrkcyl; /* drive tracks (heads) per cylinder */ uint32_t bc_nsectrk; /* drive sectors per track */ struct dkbad bc_bt; /* the actual bad sector table */ daddr_t bc_bb[NBT_BAD+1];/* LBA-ized version */ }; /* * bad144_init -- * Initialize bad144 sector forwarding context. Returns a context * to be used for bad144 remapping, or NULL if bad144 can't be * used on this drive due to geometry parameters being out of range. */ struct bad144_context * bad144_init(uint32_t secsize, uint32_t ncyl, uint32_t ntrkcyl, uint32_t nsectrk) { int i; KASSERT(secsize != 0); KASSERT(ncyl != 0); KASSERT(ntrkcyl != 0); KASSERT(nsectrk != 0); if (ncyl > BAD144_MAXCYLNO || ntrkcyl > BAD144_MAXTRKNO || nsectrk > BAD144_MAXSECNO) { /* Can't do bad144 on this drive. */ return NULL; } struct bad144_context *ctx = kmem_zalloc(sizeof(*ctx), KM_SLEEP); ctx->bc_secsize = secsize; ctx->bc_ncyl = ncyl; ctx->bc_ntrkcyl = ntrkcyl; ctx->bc_nsectrk = nsectrk; for (i = 0; i < NBT_BAD; i++) { ctx->bc_bt.bt_bad[i].bt_cyl = ctx->bc_bt.bt_bad[i].bt_trksec = 0xffff; ctx->bc_bb[i] = (daddr_t)-1; } /* There is an extra slot to terminate the list. */ ctx->bc_bb[NBT_BAD] = (daddr_t)-1; return ctx; } /* * bad144_fini -- * Dispose of a bad144 sector forwarding context. */ void bad144_fini(struct bad144_context * const ctx) { if (ctx != NULL) { kmem_free(ctx, sizeof(*ctx)); } } /* * This empty slot check comes from Chuck Cranor's Xylogics SMD * drivers. It differs from the usual -1 check for cylinder, * but presumably he did it this way because bad144 tables like * this are found in the wild ?? (N.B. old SunOS versions seem * to initialize bt_cyl to 0xffff but don't bother with bt_trksec?) */ #define EMPTY_SLOT(b) \ ((bt->bt_bad[i].bt_cyl == 0xffff || \ bt->bt_bad[i].bt_cyl == 0) && \ bt->bt_bad[i].bt_trksec == 0xffff) /* * bad144_set -- * Set the bad144 sector fowarding table from the provided * buffer. */ int bad144_set(struct bad144_context * const ctx, const struct dkbad * const bt) { int i; daddr_t key, last_key; if (ctx == NULL) { return ENOTSUP; } KASSERT(bt != NULL); for (last_key = 0, i = 0; i < NBT_BAD; i++) { /* * All bad sector records are packed into the beginning * of the table. Once we see an empty slot, there should * be no more records. Verified below. */ if (EMPTY_SLOT(&bt->bt_bad[i])) { break; } /* * Verify the cylinder / head / sector values in the * table do not exceed the drive's geometry. */ if (bt->bt_bad[i].bt_cyl >= ctx->bc_ncyl || (bt->bt_bad[i].bt_trksec >> 8) >= ctx->bc_ntrkcyl || (bt->bt_bad[i].bt_trksec & 0xff) >= ctx->bc_nsectrk) { goto bad_table; } /* * Verify the table lists bad sectors in ascending order * and that are no duplicates. */ key = ((daddr_t)bt->bt_bad[i].bt_cyl << 16) + bt->bt_bad[i].bt_trksec; if (key <= last_key) { goto bad_table; } last_key = key; } /* * Once we see an empty slot, we must only see empty * slots. */ for (; i < NBT_BAD; i++) { if (!EMPTY_SLOT(&bt->bt_bad[i])) { goto bad_table; } } memcpy(&ctx->bc_bt, bt, sizeof(ctx->bc_bt)); for (i = 0; i < NBT_BAD; i++) { if (EMPTY_SLOT(&bt->bt_bad[i])) { ctx->bc_bb[i] = (daddr_t)-1; continue; } ctx->bc_bb[i] = (bt->bt_bad[i].bt_cyl * (ctx->bc_ntrkcyl * ctx->bc_nsectrk)) + ((bt->bt_bad[i].bt_trksec >> 8) * ctx->bc_nsectrk) + (bt->bt_bad[i].bt_trksec & 0xff); } return 0; bad_table: return EINVAL; } #define DKBAD_MAGIC 0x4321 /* * bad144_load -- * Find a bad sector table and load it into the context. */ int bad144_load(struct bad144_context * const ctx, dev_t dev, void (*strat)(struct buf *)) { struct buf *bp; int error, i = 0; if (ctx == NULL) { return ESRCH; } uint32_t nseccyl = ctx->bc_ntrkcyl * ctx->bc_nsectrk; uint32_t nsecunit = ctx->bc_ncyl * nseccyl; bp = geteblk(ctx->bc_secsize); bp->b_dev = dev; do { bp->b_oflags &= ~BO_DONE; bp->b_flags |= B_READ; bp->b_blkno = nsecunit - ctx->bc_nsectrk + i; if (ctx->bc_secsize > DEV_BSIZE) { bp->b_blkno *= ctx->bc_secsize / DEV_BSIZE; } else { bp->b_blkno /= DEV_BSIZE / ctx->bc_secsize; } bp->b_bcount = ctx->bc_secsize; bp->b_cylinder = ctx->bc_ncyl - 1; (*strat)(bp); if ((error = biowait(bp)) == 0) { struct dkbad *db = (struct dkbad *)bp->b_data; if (db->bt_mbz == 0 && db->bt_flag == DKBAD_MAGIC) { error = bad144_set(ctx, db); break; } else { error = ESRCH; } } } while (error != 0 && (i += 2) < 10 && i < ctx->bc_nsectrk); brelse(bp, BC_INVAL); return error; } /* * bad144_isbad_chs -- * Search the bad sector table looking for the specified sector. * Return the index if found, -1 if not found. * * This one does CHS addressing and is essentially the traditional * isbad() routine. */ int bad144_isbad_chs(const struct bad144_context * const ctx, uint32_t cyl, uint32_t trk, uint32_t sec) { const struct dkbad * const bt = &ctx->bc_bt; int i; daddr_t key, tkey; if (ctx == NULL) { return -1; } key = ((daddr_t)cyl << 16) + (trk << 8) + sec; for (i = 0; i < NBT_BAD; i++) { tkey = ((daddr_t)bt->bt_bad[i].bt_cyl << 16) + bt->bt_bad[i].bt_trksec; if (key == tkey) { return i; } if (EMPTY_SLOT(i) || key < tkey) { break; } } return -1; } /* * bad144_isbad_lba -- * Search the bad sector table looking for the specified sector. * Return the index if found, -1 if not found. * * This one does LBA addressing, and checks a block range, * also returning the distance to the bad sector. */ int bad144_isbad_lba(const struct bad144_context * const ctx, daddr_t blk, int nblks, int *distancep) { daddr_t blkdiff; int i; KASSERT(blk >= 0); KASSERT(nblks > 0); KASSERT(distancep != NULL); if (ctx == NULL) { return -1; } for (i = 0; (blkdiff = ctx->bc_bb[i]) != (daddr_t)-1; i++) { blkdiff -= blk; if (blkdiff < 0) { continue; } if (blkdiff < nblks) { /* * There is a bad block within this transfer. * If the distance is 0, then it's the first * block in the transfer (i.e. "blk"). Otherwise, * the distance indicates how many blocks can * be transferred before the remap must be done. */ KASSERT(blkdiff < INT_MAX); *distancep = (int)blkdiff; return i; } } return -1; }
