123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443444445446447448449450451452453454455456457458459460461462463464465466467468469470471472473474475476477478479480481482483484485486487488489490491492493494495496497498499500501502503504505506507508509510511512513514515516517518519520521522523524525526527528529530531532533534535536537538539540541542543544545546547548549550551552553554555556557558559560561562563564565566567568569570571572573574575576577578579 |
- // SPDX-License-Identifier: GPL-2.0
- #define dev_fmt(fmt) "mtdoops-pstore: " fmt
- #include <linux/kernel.h>
- #include <linux/module.h>
- #include <linux/pstore_blk.h>
- #include <linux/mtd/mtd.h>
- #include <linux/bitops.h>
- #include <linux/slab.h>
- static struct mtdpstore_context {
- int index;
- struct pstore_blk_config info;
- struct pstore_device_info dev;
- struct mtd_info *mtd;
- unsigned long *rmmap; /* removed bit map */
- unsigned long *usedmap; /* used bit map */
- /*
- * used for panic write
- * As there are no block_isbad for panic case, we should keep this
- * status before panic to ensure panic_write not failed.
- */
- unsigned long *badmap; /* bad block bit map */
- } oops_cxt;
- static int mtdpstore_block_isbad(struct mtdpstore_context *cxt, loff_t off)
- {
- int ret;
- struct mtd_info *mtd = cxt->mtd;
- u64 blknum;
- off = ALIGN_DOWN(off, mtd->erasesize);
- blknum = div_u64(off, mtd->erasesize);
- if (test_bit(blknum, cxt->badmap))
- return true;
- ret = mtd_block_isbad(mtd, off);
- if (ret < 0) {
- dev_err(&mtd->dev, "mtd_block_isbad failed, aborting\n");
- return ret;
- } else if (ret > 0) {
- set_bit(blknum, cxt->badmap);
- return true;
- }
- return false;
- }
- static inline int mtdpstore_panic_block_isbad(struct mtdpstore_context *cxt,
- loff_t off)
- {
- struct mtd_info *mtd = cxt->mtd;
- u64 blknum;
- off = ALIGN_DOWN(off, mtd->erasesize);
- blknum = div_u64(off, mtd->erasesize);
- return test_bit(blknum, cxt->badmap);
- }
- static inline void mtdpstore_mark_used(struct mtdpstore_context *cxt,
- loff_t off)
- {
- struct mtd_info *mtd = cxt->mtd;
- u64 zonenum = div_u64(off, cxt->info.kmsg_size);
- dev_dbg(&mtd->dev, "mark zone %llu used\n", zonenum);
- set_bit(zonenum, cxt->usedmap);
- }
- static inline void mtdpstore_mark_unused(struct mtdpstore_context *cxt,
- loff_t off)
- {
- struct mtd_info *mtd = cxt->mtd;
- u64 zonenum = div_u64(off, cxt->info.kmsg_size);
- dev_dbg(&mtd->dev, "mark zone %llu unused\n", zonenum);
- clear_bit(zonenum, cxt->usedmap);
- }
- static inline void mtdpstore_block_mark_unused(struct mtdpstore_context *cxt,
- loff_t off)
- {
- struct mtd_info *mtd = cxt->mtd;
- u32 zonecnt = mtd->erasesize / cxt->info.kmsg_size;
- u64 zonenum;
- off = ALIGN_DOWN(off, mtd->erasesize);
- zonenum = div_u64(off, cxt->info.kmsg_size);
- while (zonecnt > 0) {
- dev_dbg(&mtd->dev, "mark zone %llu unused\n", zonenum);
- clear_bit(zonenum, cxt->usedmap);
- zonenum++;
- zonecnt--;
- }
- }
- static inline int mtdpstore_is_used(struct mtdpstore_context *cxt, loff_t off)
- {
- u64 zonenum = div_u64(off, cxt->info.kmsg_size);
- u64 blknum = div_u64(off, cxt->mtd->erasesize);
- if (test_bit(blknum, cxt->badmap))
- return true;
- return test_bit(zonenum, cxt->usedmap);
- }
- static int mtdpstore_block_is_used(struct mtdpstore_context *cxt,
- loff_t off)
- {
- struct mtd_info *mtd = cxt->mtd;
- u32 zonecnt = mtd->erasesize / cxt->info.kmsg_size;
- u64 zonenum;
- off = ALIGN_DOWN(off, mtd->erasesize);
- zonenum = div_u64(off, cxt->info.kmsg_size);
- while (zonecnt > 0) {
- if (test_bit(zonenum, cxt->usedmap))
- return true;
- zonenum++;
- zonecnt--;
- }
- return false;
- }
- static int mtdpstore_is_empty(struct mtdpstore_context *cxt, char *buf,
- size_t size)
- {
- struct mtd_info *mtd = cxt->mtd;
- size_t sz;
- int i;
- sz = min_t(uint32_t, size, mtd->writesize / 4);
- for (i = 0; i < sz; i++) {
- if (buf[i] != (char)0xFF)
- return false;
- }
- return true;
- }
- static void mtdpstore_mark_removed(struct mtdpstore_context *cxt, loff_t off)
- {
- struct mtd_info *mtd = cxt->mtd;
- u64 zonenum = div_u64(off, cxt->info.kmsg_size);
- dev_dbg(&mtd->dev, "mark zone %llu removed\n", zonenum);
- set_bit(zonenum, cxt->rmmap);
- }
- static void mtdpstore_block_clear_removed(struct mtdpstore_context *cxt,
- loff_t off)
- {
- struct mtd_info *mtd = cxt->mtd;
- u32 zonecnt = mtd->erasesize / cxt->info.kmsg_size;
- u64 zonenum;
- off = ALIGN_DOWN(off, mtd->erasesize);
- zonenum = div_u64(off, cxt->info.kmsg_size);
- while (zonecnt > 0) {
- clear_bit(zonenum, cxt->rmmap);
- zonenum++;
- zonecnt--;
- }
- }
- static int mtdpstore_block_is_removed(struct mtdpstore_context *cxt,
- loff_t off)
- {
- struct mtd_info *mtd = cxt->mtd;
- u32 zonecnt = mtd->erasesize / cxt->info.kmsg_size;
- u64 zonenum;
- off = ALIGN_DOWN(off, mtd->erasesize);
- zonenum = div_u64(off, cxt->info.kmsg_size);
- while (zonecnt > 0) {
- if (test_bit(zonenum, cxt->rmmap))
- return true;
- zonenum++;
- zonecnt--;
- }
- return false;
- }
- static int mtdpstore_erase_do(struct mtdpstore_context *cxt, loff_t off)
- {
- struct mtd_info *mtd = cxt->mtd;
- struct erase_info erase;
- int ret;
- off = ALIGN_DOWN(off, cxt->mtd->erasesize);
- dev_dbg(&mtd->dev, "try to erase off 0x%llx\n", off);
- erase.len = cxt->mtd->erasesize;
- erase.addr = off;
- ret = mtd_erase(cxt->mtd, &erase);
- if (!ret)
- mtdpstore_block_clear_removed(cxt, off);
- else
- dev_err(&mtd->dev, "erase of region [0x%llx, 0x%llx] on \"%s\" failed\n",
- (unsigned long long)erase.addr,
- (unsigned long long)erase.len, cxt->info.device);
- return ret;
- }
- /*
- * called while removing file
- *
- * Avoiding over erasing, do erase block only when the whole block is unused.
- * If the block contains valid log, do erase lazily on flush_removed() when
- * unregister.
- */
- static ssize_t mtdpstore_erase(size_t size, loff_t off)
- {
- struct mtdpstore_context *cxt = &oops_cxt;
- if (mtdpstore_block_isbad(cxt, off))
- return -EIO;
- mtdpstore_mark_unused(cxt, off);
- /* If the block still has valid data, mtdpstore do erase lazily */
- if (likely(mtdpstore_block_is_used(cxt, off))) {
- mtdpstore_mark_removed(cxt, off);
- return 0;
- }
- /* all zones are unused, erase it */
- return mtdpstore_erase_do(cxt, off);
- }
- /*
- * What is security for mtdpstore?
- * As there is no erase for panic case, we should ensure at least one zone
- * is writable. Otherwise, panic write will fail.
- * If zone is used, write operation will return -ENOMSG, which means that
- * pstore/blk will try one by one until gets an empty zone. So, it is not
- * needed to ensure the next zone is empty, but at least one.
- */
- static int mtdpstore_security(struct mtdpstore_context *cxt, loff_t off)
- {
- int ret = 0, i;
- struct mtd_info *mtd = cxt->mtd;
- u32 zonenum = (u32)div_u64(off, cxt->info.kmsg_size);
- u32 zonecnt = (u32)div_u64(cxt->mtd->size, cxt->info.kmsg_size);
- u32 blkcnt = (u32)div_u64(cxt->mtd->size, cxt->mtd->erasesize);
- u32 erasesize = cxt->mtd->erasesize;
- for (i = 0; i < zonecnt; i++) {
- u32 num = (zonenum + i) % zonecnt;
- /* found empty zone */
- if (!test_bit(num, cxt->usedmap))
- return 0;
- }
- /* If there is no any empty zone, we have no way but to do erase */
- while (blkcnt--) {
- div64_u64_rem(off + erasesize, cxt->mtd->size, (u64 *)&off);
- if (mtdpstore_block_isbad(cxt, off))
- continue;
- ret = mtdpstore_erase_do(cxt, off);
- if (!ret) {
- mtdpstore_block_mark_unused(cxt, off);
- break;
- }
- }
- if (ret)
- dev_err(&mtd->dev, "all blocks bad!\n");
- dev_dbg(&mtd->dev, "end security\n");
- return ret;
- }
- static ssize_t mtdpstore_write(const char *buf, size_t size, loff_t off)
- {
- struct mtdpstore_context *cxt = &oops_cxt;
- struct mtd_info *mtd = cxt->mtd;
- size_t retlen;
- int ret;
- if (mtdpstore_block_isbad(cxt, off))
- return -ENOMSG;
- /* zone is used, please try next one */
- if (mtdpstore_is_used(cxt, off))
- return -ENOMSG;
- dev_dbg(&mtd->dev, "try to write off 0x%llx size %zu\n", off, size);
- ret = mtd_write(cxt->mtd, off, size, &retlen, (u_char *)buf);
- if (ret < 0 || retlen != size) {
- dev_err(&mtd->dev, "write failure at %lld (%zu of %zu written), err %d\n",
- off, retlen, size, ret);
- return -EIO;
- }
- mtdpstore_mark_used(cxt, off);
- mtdpstore_security(cxt, off);
- return retlen;
- }
- static inline bool mtdpstore_is_io_error(int ret)
- {
- return ret < 0 && !mtd_is_bitflip(ret) && !mtd_is_eccerr(ret);
- }
- /*
- * All zones will be read as pstore/blk will read zone one by one when do
- * recover.
- */
- static ssize_t mtdpstore_read(char *buf, size_t size, loff_t off)
- {
- struct mtdpstore_context *cxt = &oops_cxt;
- struct mtd_info *mtd = cxt->mtd;
- size_t retlen, done;
- int ret;
- if (mtdpstore_block_isbad(cxt, off))
- return -ENOMSG;
- dev_dbg(&mtd->dev, "try to read off 0x%llx size %zu\n", off, size);
- for (done = 0, retlen = 0; done < size; done += retlen) {
- retlen = 0;
- ret = mtd_read(cxt->mtd, off + done, size - done, &retlen,
- (u_char *)buf + done);
- if (mtdpstore_is_io_error(ret)) {
- dev_err(&mtd->dev, "read failure at %lld (%zu of %zu read), err %d\n",
- off + done, retlen, size - done, ret);
- /* the zone may be broken, try next one */
- return -ENOMSG;
- }
- /*
- * ECC error. The impact on log data is so small. Maybe we can
- * still read it and try to understand. So mtdpstore just hands
- * over what it gets and user can judge whether the data is
- * valid or not.
- */
- if (mtd_is_eccerr(ret)) {
- dev_err(&mtd->dev, "ecc error at %lld (%zu of %zu read), err %d\n",
- off + done, retlen, size - done, ret);
- /* driver may not set retlen when ecc error */
- retlen = retlen == 0 ? size - done : retlen;
- }
- }
- if (mtdpstore_is_empty(cxt, buf, size))
- mtdpstore_mark_unused(cxt, off);
- else
- mtdpstore_mark_used(cxt, off);
- mtdpstore_security(cxt, off);
- return retlen;
- }
- static ssize_t mtdpstore_panic_write(const char *buf, size_t size, loff_t off)
- {
- struct mtdpstore_context *cxt = &oops_cxt;
- struct mtd_info *mtd = cxt->mtd;
- size_t retlen;
- int ret;
- if (mtdpstore_panic_block_isbad(cxt, off))
- return -ENOMSG;
- /* zone is used, please try next one */
- if (mtdpstore_is_used(cxt, off))
- return -ENOMSG;
- ret = mtd_panic_write(cxt->mtd, off, size, &retlen, (u_char *)buf);
- if (ret < 0 || size != retlen) {
- dev_err(&mtd->dev, "panic write failure at %lld (%zu of %zu read), err %d\n",
- off, retlen, size, ret);
- return -EIO;
- }
- mtdpstore_mark_used(cxt, off);
- return retlen;
- }
- static void mtdpstore_notify_add(struct mtd_info *mtd)
- {
- int ret;
- struct mtdpstore_context *cxt = &oops_cxt;
- struct pstore_blk_config *info = &cxt->info;
- unsigned long longcnt;
- if (!strcmp(mtd->name, info->device))
- cxt->index = mtd->index;
- if (mtd->index != cxt->index || cxt->index < 0)
- return;
- dev_dbg(&mtd->dev, "found matching MTD device %s\n", mtd->name);
- if (mtd->size < info->kmsg_size * 2) {
- dev_err(&mtd->dev, "MTD partition %d not big enough\n",
- mtd->index);
- return;
- }
- /*
- * kmsg_size must be aligned to 4096 Bytes, which is limited by
- * psblk. The default value of kmsg_size is 64KB. If kmsg_size
- * is larger than erasesize, some errors will occur since mtdpstore
- * is designed on it.
- */
- if (mtd->erasesize < info->kmsg_size) {
- dev_err(&mtd->dev, "eraseblock size of MTD partition %d too small\n",
- mtd->index);
- return;
- }
- if (unlikely(info->kmsg_size % mtd->writesize)) {
- dev_err(&mtd->dev, "record size %lu KB must align to write size %d KB\n",
- info->kmsg_size / 1024,
- mtd->writesize / 1024);
- return;
- }
- longcnt = BITS_TO_LONGS(div_u64(mtd->size, info->kmsg_size));
- cxt->rmmap = kcalloc(longcnt, sizeof(long), GFP_KERNEL);
- cxt->usedmap = kcalloc(longcnt, sizeof(long), GFP_KERNEL);
- longcnt = BITS_TO_LONGS(div_u64(mtd->size, mtd->erasesize));
- cxt->badmap = kcalloc(longcnt, sizeof(long), GFP_KERNEL);
- /* just support dmesg right now */
- cxt->dev.flags = PSTORE_FLAGS_DMESG;
- cxt->dev.zone.read = mtdpstore_read;
- cxt->dev.zone.write = mtdpstore_write;
- cxt->dev.zone.erase = mtdpstore_erase;
- cxt->dev.zone.panic_write = mtdpstore_panic_write;
- cxt->dev.zone.total_size = mtd->size;
- ret = register_pstore_device(&cxt->dev);
- if (ret) {
- dev_err(&mtd->dev, "mtd%d register to psblk failed\n",
- mtd->index);
- return;
- }
- cxt->mtd = mtd;
- dev_info(&mtd->dev, "Attached to MTD device %d\n", mtd->index);
- }
- static int mtdpstore_flush_removed_do(struct mtdpstore_context *cxt,
- loff_t off, size_t size)
- {
- struct mtd_info *mtd = cxt->mtd;
- u_char *buf;
- int ret;
- size_t retlen;
- struct erase_info erase;
- buf = kmalloc(mtd->erasesize, GFP_KERNEL);
- if (!buf)
- return -ENOMEM;
- /* 1st. read to cache */
- ret = mtd_read(mtd, off, mtd->erasesize, &retlen, buf);
- if (mtdpstore_is_io_error(ret))
- goto free;
- /* 2nd. erase block */
- erase.len = mtd->erasesize;
- erase.addr = off;
- ret = mtd_erase(mtd, &erase);
- if (ret)
- goto free;
- /* 3rd. write back */
- while (size) {
- unsigned int zonesize = cxt->info.kmsg_size;
- /* there is valid data on block, write back */
- if (mtdpstore_is_used(cxt, off)) {
- ret = mtd_write(mtd, off, zonesize, &retlen, buf);
- if (ret)
- dev_err(&mtd->dev, "write failure at %lld (%zu of %u written), err %d\n",
- off, retlen, zonesize, ret);
- }
- off += zonesize;
- size -= min_t(unsigned int, zonesize, size);
- }
- free:
- kfree(buf);
- return ret;
- }
- /*
- * What does mtdpstore_flush_removed() do?
- * When user remove any log file on pstore filesystem, mtdpstore should do
- * something to ensure log file removed. If the whole block is no longer used,
- * it's nice to erase the block. However if the block still contains valid log,
- * what mtdpstore can do is to erase and write the valid log back.
- */
- static int mtdpstore_flush_removed(struct mtdpstore_context *cxt)
- {
- struct mtd_info *mtd = cxt->mtd;
- int ret;
- loff_t off;
- u32 blkcnt = (u32)div_u64(mtd->size, mtd->erasesize);
- for (off = 0; blkcnt > 0; blkcnt--, off += mtd->erasesize) {
- ret = mtdpstore_block_isbad(cxt, off);
- if (ret)
- continue;
- ret = mtdpstore_block_is_removed(cxt, off);
- if (!ret)
- continue;
- ret = mtdpstore_flush_removed_do(cxt, off, mtd->erasesize);
- if (ret)
- return ret;
- }
- return 0;
- }
- static void mtdpstore_notify_remove(struct mtd_info *mtd)
- {
- struct mtdpstore_context *cxt = &oops_cxt;
- if (mtd->index != cxt->index || cxt->index < 0)
- return;
- mtdpstore_flush_removed(cxt);
- unregister_pstore_device(&cxt->dev);
- kfree(cxt->badmap);
- kfree(cxt->usedmap);
- kfree(cxt->rmmap);
- cxt->mtd = NULL;
- cxt->index = -1;
- }
- static struct mtd_notifier mtdpstore_notifier = {
- .add = mtdpstore_notify_add,
- .remove = mtdpstore_notify_remove,
- };
- static int __init mtdpstore_init(void)
- {
- int ret;
- struct mtdpstore_context *cxt = &oops_cxt;
- struct pstore_blk_config *info = &cxt->info;
- ret = pstore_blk_get_config(info);
- if (unlikely(ret))
- return ret;
- if (strlen(info->device) == 0) {
- pr_err("mtd device must be supplied (device name is empty)\n");
- return -EINVAL;
- }
- if (!info->kmsg_size) {
- pr_err("no backend enabled (kmsg_size is 0)\n");
- return -EINVAL;
- }
- /* Setup the MTD device to use */
- ret = kstrtoint((char *)info->device, 0, &cxt->index);
- if (ret)
- cxt->index = -1;
- register_mtd_user(&mtdpstore_notifier);
- return 0;
- }
- module_init(mtdpstore_init);
- static void __exit mtdpstore_exit(void)
- {
- unregister_mtd_user(&mtdpstore_notifier);
- }
- module_exit(mtdpstore_exit);
- MODULE_LICENSE("GPL");
- MODULE_AUTHOR("WeiXiong Liao <[email protected]>");
- MODULE_DESCRIPTION("MTD backend for pstore/blk");
|