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- // SPDX-License-Identifier: GPL-2.0
- /*
- * Provide a pstore intermediate backend, organized into kernel memory
- * allocated zones that are then mapped and flushed into a single
- * contiguous region on a storage backend of some kind (block, mtd, etc).
- */
- #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
- #include <linux/kernel.h>
- #include <linux/module.h>
- #include <linux/slab.h>
- #include <linux/mount.h>
- #include <linux/printk.h>
- #include <linux/fs.h>
- #include <linux/pstore_zone.h>
- #include <linux/kdev_t.h>
- #include <linux/device.h>
- #include <linux/namei.h>
- #include <linux/fcntl.h>
- #include <linux/uio.h>
- #include <linux/writeback.h>
- #include "internal.h"
- /**
- * struct psz_head - header of zone to flush to storage
- *
- * @sig: signature to indicate header (PSZ_SIG xor PSZONE-type value)
- * @datalen: length of data in @data
- * @start: offset into @data where the beginning of the stored bytes begin
- * @data: zone data.
- */
- struct psz_buffer {
- #define PSZ_SIG (0x43474244) /* DBGC */
- uint32_t sig;
- atomic_t datalen;
- atomic_t start;
- uint8_t data[];
- };
- /**
- * struct psz_kmsg_header - kmsg dump-specific header to flush to storage
- *
- * @magic: magic num for kmsg dump header
- * @time: kmsg dump trigger time
- * @compressed: whether conpressed
- * @counter: kmsg dump counter
- * @reason: the kmsg dump reason (e.g. oops, panic, etc)
- * @data: pointer to log data
- *
- * This is a sub-header for a kmsg dump, trailing after &psz_buffer.
- */
- struct psz_kmsg_header {
- #define PSTORE_KMSG_HEADER_MAGIC 0x4dfc3ae5 /* Just a random number */
- uint32_t magic;
- struct timespec64 time;
- bool compressed;
- uint32_t counter;
- enum kmsg_dump_reason reason;
- uint8_t data[];
- };
- /**
- * struct pstore_zone - single stored buffer
- *
- * @off: zone offset of storage
- * @type: front-end type for this zone
- * @name: front-end name for this zone
- * @buffer: pointer to data buffer managed by this zone
- * @oldbuf: pointer to old data buffer
- * @buffer_size: bytes in @buffer->data
- * @should_recover: whether this zone should recover from storage
- * @dirty: whether the data in @buffer dirty
- *
- * zone structure in memory.
- */
- struct pstore_zone {
- loff_t off;
- const char *name;
- enum pstore_type_id type;
- struct psz_buffer *buffer;
- struct psz_buffer *oldbuf;
- size_t buffer_size;
- bool should_recover;
- atomic_t dirty;
- };
- /**
- * struct psz_context - all about running state of pstore/zone
- *
- * @kpszs: kmsg dump storage zones
- * @ppsz: pmsg storage zone
- * @cpsz: console storage zone
- * @fpszs: ftrace storage zones
- * @kmsg_max_cnt: max count of @kpszs
- * @kmsg_read_cnt: counter of total read kmsg dumps
- * @kmsg_write_cnt: counter of total kmsg dump writes
- * @pmsg_read_cnt: counter of total read pmsg zone
- * @console_read_cnt: counter of total read console zone
- * @ftrace_max_cnt: max count of @fpszs
- * @ftrace_read_cnt: counter of max read ftrace zone
- * @oops_counter: counter of oops dumps
- * @panic_counter: counter of panic dumps
- * @recovered: whether finished recovering data from storage
- * @on_panic: whether panic is happening
- * @pstore_zone_info_lock: lock to @pstore_zone_info
- * @pstore_zone_info: information from backend
- * @pstore: structure for pstore
- */
- struct psz_context {
- struct pstore_zone **kpszs;
- struct pstore_zone *ppsz;
- struct pstore_zone *cpsz;
- struct pstore_zone **fpszs;
- unsigned int kmsg_max_cnt;
- unsigned int kmsg_read_cnt;
- unsigned int kmsg_write_cnt;
- unsigned int pmsg_read_cnt;
- unsigned int console_read_cnt;
- unsigned int ftrace_max_cnt;
- unsigned int ftrace_read_cnt;
- /*
- * These counters should be calculated during recovery.
- * It records the oops/panic times after crashes rather than boots.
- */
- unsigned int oops_counter;
- unsigned int panic_counter;
- atomic_t recovered;
- atomic_t on_panic;
- /*
- * pstore_zone_info_lock protects this entire structure during calls
- * to register_pstore_zone()/unregister_pstore_zone().
- */
- struct mutex pstore_zone_info_lock;
- struct pstore_zone_info *pstore_zone_info;
- struct pstore_info pstore;
- };
- static struct psz_context pstore_zone_cxt;
- static void psz_flush_all_dirty_zones(struct work_struct *);
- static DECLARE_DELAYED_WORK(psz_cleaner, psz_flush_all_dirty_zones);
- /**
- * enum psz_flush_mode - flush mode for psz_zone_write()
- *
- * @FLUSH_NONE: do not flush to storage but update data on memory
- * @FLUSH_PART: just flush part of data including meta data to storage
- * @FLUSH_META: just flush meta data of zone to storage
- * @FLUSH_ALL: flush all of zone
- */
- enum psz_flush_mode {
- FLUSH_NONE = 0,
- FLUSH_PART,
- FLUSH_META,
- FLUSH_ALL,
- };
- static inline int buffer_datalen(struct pstore_zone *zone)
- {
- return atomic_read(&zone->buffer->datalen);
- }
- static inline int buffer_start(struct pstore_zone *zone)
- {
- return atomic_read(&zone->buffer->start);
- }
- static inline bool is_on_panic(void)
- {
- return atomic_read(&pstore_zone_cxt.on_panic);
- }
- static ssize_t psz_zone_read_buffer(struct pstore_zone *zone, char *buf,
- size_t len, unsigned long off)
- {
- if (!buf || !zone || !zone->buffer)
- return -EINVAL;
- if (off > zone->buffer_size)
- return -EINVAL;
- len = min_t(size_t, len, zone->buffer_size - off);
- memcpy(buf, zone->buffer->data + off, len);
- return len;
- }
- static int psz_zone_read_oldbuf(struct pstore_zone *zone, char *buf,
- size_t len, unsigned long off)
- {
- if (!buf || !zone || !zone->oldbuf)
- return -EINVAL;
- if (off > zone->buffer_size)
- return -EINVAL;
- len = min_t(size_t, len, zone->buffer_size - off);
- memcpy(buf, zone->oldbuf->data + off, len);
- return 0;
- }
- static int psz_zone_write(struct pstore_zone *zone,
- enum psz_flush_mode flush_mode, const char *buf,
- size_t len, unsigned long off)
- {
- struct pstore_zone_info *info = pstore_zone_cxt.pstore_zone_info;
- ssize_t wcnt = 0;
- ssize_t (*writeop)(const char *buf, size_t bytes, loff_t pos);
- size_t wlen;
- if (off > zone->buffer_size)
- return -EINVAL;
- wlen = min_t(size_t, len, zone->buffer_size - off);
- if (buf && wlen) {
- memcpy(zone->buffer->data + off, buf, wlen);
- atomic_set(&zone->buffer->datalen, wlen + off);
- }
- /* avoid to damage old records */
- if (!is_on_panic() && !atomic_read(&pstore_zone_cxt.recovered))
- goto dirty;
- writeop = is_on_panic() ? info->panic_write : info->write;
- if (!writeop)
- goto dirty;
- switch (flush_mode) {
- case FLUSH_NONE:
- if (unlikely(buf && wlen))
- goto dirty;
- return 0;
- case FLUSH_PART:
- wcnt = writeop((const char *)zone->buffer->data + off, wlen,
- zone->off + sizeof(*zone->buffer) + off);
- if (wcnt != wlen)
- goto dirty;
- fallthrough;
- case FLUSH_META:
- wlen = sizeof(struct psz_buffer);
- wcnt = writeop((const char *)zone->buffer, wlen, zone->off);
- if (wcnt != wlen)
- goto dirty;
- break;
- case FLUSH_ALL:
- wlen = zone->buffer_size + sizeof(*zone->buffer);
- wcnt = writeop((const char *)zone->buffer, wlen, zone->off);
- if (wcnt != wlen)
- goto dirty;
- break;
- }
- return 0;
- dirty:
- /* no need to mark dirty if going to try next zone */
- if (wcnt == -ENOMSG)
- return -ENOMSG;
- atomic_set(&zone->dirty, true);
- /* flush dirty zones nicely */
- if (wcnt == -EBUSY && !is_on_panic())
- schedule_delayed_work(&psz_cleaner, msecs_to_jiffies(500));
- return -EBUSY;
- }
- static int psz_flush_dirty_zone(struct pstore_zone *zone)
- {
- int ret;
- if (unlikely(!zone))
- return -EINVAL;
- if (unlikely(!atomic_read(&pstore_zone_cxt.recovered)))
- return -EBUSY;
- if (!atomic_xchg(&zone->dirty, false))
- return 0;
- ret = psz_zone_write(zone, FLUSH_ALL, NULL, 0, 0);
- if (ret)
- atomic_set(&zone->dirty, true);
- return ret;
- }
- static int psz_flush_dirty_zones(struct pstore_zone **zones, unsigned int cnt)
- {
- int i, ret;
- struct pstore_zone *zone;
- if (!zones)
- return -EINVAL;
- for (i = 0; i < cnt; i++) {
- zone = zones[i];
- if (!zone)
- return -EINVAL;
- ret = psz_flush_dirty_zone(zone);
- if (ret)
- return ret;
- }
- return 0;
- }
- static int psz_move_zone(struct pstore_zone *old, struct pstore_zone *new)
- {
- const char *data = (const char *)old->buffer->data;
- int ret;
- ret = psz_zone_write(new, FLUSH_ALL, data, buffer_datalen(old), 0);
- if (ret) {
- atomic_set(&new->buffer->datalen, 0);
- atomic_set(&new->dirty, false);
- return ret;
- }
- atomic_set(&old->buffer->datalen, 0);
- return 0;
- }
- static void psz_flush_all_dirty_zones(struct work_struct *work)
- {
- struct psz_context *cxt = &pstore_zone_cxt;
- int ret = 0;
- if (cxt->ppsz)
- ret |= psz_flush_dirty_zone(cxt->ppsz);
- if (cxt->cpsz)
- ret |= psz_flush_dirty_zone(cxt->cpsz);
- if (cxt->kpszs)
- ret |= psz_flush_dirty_zones(cxt->kpszs, cxt->kmsg_max_cnt);
- if (cxt->fpszs)
- ret |= psz_flush_dirty_zones(cxt->fpszs, cxt->ftrace_max_cnt);
- if (ret && cxt->pstore_zone_info)
- schedule_delayed_work(&psz_cleaner, msecs_to_jiffies(1000));
- }
- static int psz_kmsg_recover_data(struct psz_context *cxt)
- {
- struct pstore_zone_info *info = cxt->pstore_zone_info;
- struct pstore_zone *zone = NULL;
- struct psz_buffer *buf;
- unsigned long i;
- ssize_t rcnt;
- if (!info->read)
- return -EINVAL;
- for (i = 0; i < cxt->kmsg_max_cnt; i++) {
- zone = cxt->kpszs[i];
- if (unlikely(!zone))
- return -EINVAL;
- if (atomic_read(&zone->dirty)) {
- unsigned int wcnt = cxt->kmsg_write_cnt;
- struct pstore_zone *new = cxt->kpszs[wcnt];
- int ret;
- ret = psz_move_zone(zone, new);
- if (ret) {
- pr_err("move zone from %lu to %d failed\n",
- i, wcnt);
- return ret;
- }
- cxt->kmsg_write_cnt = (wcnt + 1) % cxt->kmsg_max_cnt;
- }
- if (!zone->should_recover)
- continue;
- buf = zone->buffer;
- rcnt = info->read((char *)buf, zone->buffer_size + sizeof(*buf),
- zone->off);
- if (rcnt != zone->buffer_size + sizeof(*buf))
- return (int)rcnt < 0 ? (int)rcnt : -EIO;
- }
- return 0;
- }
- static int psz_kmsg_recover_meta(struct psz_context *cxt)
- {
- struct pstore_zone_info *info = cxt->pstore_zone_info;
- struct pstore_zone *zone;
- size_t rcnt, len;
- struct psz_buffer *buf;
- struct psz_kmsg_header *hdr;
- struct timespec64 time = { };
- unsigned long i;
- /*
- * Recover may on panic, we can't allocate any memory by kmalloc.
- * So, we use local array instead.
- */
- char buffer_header[sizeof(*buf) + sizeof(*hdr)] = {0};
- if (!info->read)
- return -EINVAL;
- len = sizeof(*buf) + sizeof(*hdr);
- buf = (struct psz_buffer *)buffer_header;
- for (i = 0; i < cxt->kmsg_max_cnt; i++) {
- zone = cxt->kpszs[i];
- if (unlikely(!zone))
- return -EINVAL;
- rcnt = info->read((char *)buf, len, zone->off);
- if (rcnt == -ENOMSG) {
- pr_debug("%s with id %lu may be broken, skip\n",
- zone->name, i);
- continue;
- } else if (rcnt != len) {
- pr_err("read %s with id %lu failed\n", zone->name, i);
- return (int)rcnt < 0 ? (int)rcnt : -EIO;
- }
- if (buf->sig != zone->buffer->sig) {
- pr_debug("no valid data in kmsg dump zone %lu\n", i);
- continue;
- }
- if (zone->buffer_size < atomic_read(&buf->datalen)) {
- pr_info("found overtop zone: %s: id %lu, off %lld, size %zu\n",
- zone->name, i, zone->off,
- zone->buffer_size);
- continue;
- }
- hdr = (struct psz_kmsg_header *)buf->data;
- if (hdr->magic != PSTORE_KMSG_HEADER_MAGIC) {
- pr_info("found invalid zone: %s: id %lu, off %lld, size %zu\n",
- zone->name, i, zone->off,
- zone->buffer_size);
- continue;
- }
- /*
- * we get the newest zone, and the next one must be the oldest
- * or unused zone, because we do write one by one like a circle.
- */
- if (hdr->time.tv_sec >= time.tv_sec) {
- time.tv_sec = hdr->time.tv_sec;
- cxt->kmsg_write_cnt = (i + 1) % cxt->kmsg_max_cnt;
- }
- if (hdr->reason == KMSG_DUMP_OOPS)
- cxt->oops_counter =
- max(cxt->oops_counter, hdr->counter);
- else if (hdr->reason == KMSG_DUMP_PANIC)
- cxt->panic_counter =
- max(cxt->panic_counter, hdr->counter);
- if (!atomic_read(&buf->datalen)) {
- pr_debug("found erased zone: %s: id %lu, off %lld, size %zu, datalen %d\n",
- zone->name, i, zone->off,
- zone->buffer_size,
- atomic_read(&buf->datalen));
- continue;
- }
- if (!is_on_panic())
- zone->should_recover = true;
- pr_debug("found nice zone: %s: id %lu, off %lld, size %zu, datalen %d\n",
- zone->name, i, zone->off,
- zone->buffer_size, atomic_read(&buf->datalen));
- }
- return 0;
- }
- static int psz_kmsg_recover(struct psz_context *cxt)
- {
- int ret;
- if (!cxt->kpszs)
- return 0;
- ret = psz_kmsg_recover_meta(cxt);
- if (ret)
- goto recover_fail;
- ret = psz_kmsg_recover_data(cxt);
- if (ret)
- goto recover_fail;
- return 0;
- recover_fail:
- pr_debug("psz_recover_kmsg failed\n");
- return ret;
- }
- static int psz_recover_zone(struct psz_context *cxt, struct pstore_zone *zone)
- {
- struct pstore_zone_info *info = cxt->pstore_zone_info;
- struct psz_buffer *oldbuf, tmpbuf;
- int ret = 0;
- char *buf;
- ssize_t rcnt, len, start, off;
- if (!zone || zone->oldbuf)
- return 0;
- if (is_on_panic()) {
- /* save data as much as possible */
- psz_flush_dirty_zone(zone);
- return 0;
- }
- if (unlikely(!info->read))
- return -EINVAL;
- len = sizeof(struct psz_buffer);
- rcnt = info->read((char *)&tmpbuf, len, zone->off);
- if (rcnt != len) {
- pr_debug("read zone %s failed\n", zone->name);
- return (int)rcnt < 0 ? (int)rcnt : -EIO;
- }
- if (tmpbuf.sig != zone->buffer->sig) {
- pr_debug("no valid data in zone %s\n", zone->name);
- return 0;
- }
- if (zone->buffer_size < atomic_read(&tmpbuf.datalen) ||
- zone->buffer_size < atomic_read(&tmpbuf.start)) {
- pr_info("found overtop zone: %s: off %lld, size %zu\n",
- zone->name, zone->off, zone->buffer_size);
- /* just keep going */
- return 0;
- }
- if (!atomic_read(&tmpbuf.datalen)) {
- pr_debug("found erased zone: %s: off %lld, size %zu, datalen %d\n",
- zone->name, zone->off, zone->buffer_size,
- atomic_read(&tmpbuf.datalen));
- return 0;
- }
- pr_debug("found nice zone: %s: off %lld, size %zu, datalen %d\n",
- zone->name, zone->off, zone->buffer_size,
- atomic_read(&tmpbuf.datalen));
- len = atomic_read(&tmpbuf.datalen) + sizeof(*oldbuf);
- oldbuf = kzalloc(len, GFP_KERNEL);
- if (!oldbuf)
- return -ENOMEM;
- memcpy(oldbuf, &tmpbuf, sizeof(*oldbuf));
- buf = (char *)oldbuf + sizeof(*oldbuf);
- len = atomic_read(&oldbuf->datalen);
- start = atomic_read(&oldbuf->start);
- off = zone->off + sizeof(*oldbuf);
- /* get part of data */
- rcnt = info->read(buf, len - start, off + start);
- if (rcnt != len - start) {
- pr_err("read zone %s failed\n", zone->name);
- ret = (int)rcnt < 0 ? (int)rcnt : -EIO;
- goto free_oldbuf;
- }
- /* get the rest of data */
- rcnt = info->read(buf + len - start, start, off);
- if (rcnt != start) {
- pr_err("read zone %s failed\n", zone->name);
- ret = (int)rcnt < 0 ? (int)rcnt : -EIO;
- goto free_oldbuf;
- }
- zone->oldbuf = oldbuf;
- psz_flush_dirty_zone(zone);
- return 0;
- free_oldbuf:
- kfree(oldbuf);
- return ret;
- }
- static int psz_recover_zones(struct psz_context *cxt,
- struct pstore_zone **zones, unsigned int cnt)
- {
- int ret;
- unsigned int i;
- struct pstore_zone *zone;
- if (!zones)
- return 0;
- for (i = 0; i < cnt; i++) {
- zone = zones[i];
- if (unlikely(!zone))
- continue;
- ret = psz_recover_zone(cxt, zone);
- if (ret)
- goto recover_fail;
- }
- return 0;
- recover_fail:
- pr_debug("recover %s[%u] failed\n", zone->name, i);
- return ret;
- }
- /**
- * psz_recovery() - recover data from storage
- * @cxt: the context of pstore/zone
- *
- * recovery means reading data back from storage after rebooting
- *
- * Return: 0 on success, others on failure.
- */
- static inline int psz_recovery(struct psz_context *cxt)
- {
- int ret;
- if (atomic_read(&cxt->recovered))
- return 0;
- ret = psz_kmsg_recover(cxt);
- if (ret)
- goto out;
- ret = psz_recover_zone(cxt, cxt->ppsz);
- if (ret)
- goto out;
- ret = psz_recover_zone(cxt, cxt->cpsz);
- if (ret)
- goto out;
- ret = psz_recover_zones(cxt, cxt->fpszs, cxt->ftrace_max_cnt);
- out:
- if (unlikely(ret))
- pr_err("recover failed\n");
- else {
- pr_debug("recover end!\n");
- atomic_set(&cxt->recovered, 1);
- }
- return ret;
- }
- static int psz_pstore_open(struct pstore_info *psi)
- {
- struct psz_context *cxt = psi->data;
- cxt->kmsg_read_cnt = 0;
- cxt->pmsg_read_cnt = 0;
- cxt->console_read_cnt = 0;
- cxt->ftrace_read_cnt = 0;
- return 0;
- }
- static inline bool psz_old_ok(struct pstore_zone *zone)
- {
- if (zone && zone->oldbuf && atomic_read(&zone->oldbuf->datalen))
- return true;
- return false;
- }
- static inline bool psz_ok(struct pstore_zone *zone)
- {
- if (zone && zone->buffer && buffer_datalen(zone))
- return true;
- return false;
- }
- static inline int psz_kmsg_erase(struct psz_context *cxt,
- struct pstore_zone *zone, struct pstore_record *record)
- {
- struct psz_buffer *buffer = zone->buffer;
- struct psz_kmsg_header *hdr =
- (struct psz_kmsg_header *)buffer->data;
- size_t size;
- if (unlikely(!psz_ok(zone)))
- return 0;
- /* this zone is already updated, no need to erase */
- if (record->count != hdr->counter)
- return 0;
- size = buffer_datalen(zone) + sizeof(*zone->buffer);
- atomic_set(&zone->buffer->datalen, 0);
- if (cxt->pstore_zone_info->erase)
- return cxt->pstore_zone_info->erase(size, zone->off);
- else
- return psz_zone_write(zone, FLUSH_META, NULL, 0, 0);
- }
- static inline int psz_record_erase(struct psz_context *cxt,
- struct pstore_zone *zone)
- {
- if (unlikely(!psz_old_ok(zone)))
- return 0;
- kfree(zone->oldbuf);
- zone->oldbuf = NULL;
- /*
- * if there are new data in zone buffer, that means the old data
- * are already invalid. It is no need to flush 0 (erase) to
- * block device.
- */
- if (!buffer_datalen(zone))
- return psz_zone_write(zone, FLUSH_META, NULL, 0, 0);
- psz_flush_dirty_zone(zone);
- return 0;
- }
- static int psz_pstore_erase(struct pstore_record *record)
- {
- struct psz_context *cxt = record->psi->data;
- switch (record->type) {
- case PSTORE_TYPE_DMESG:
- if (record->id >= cxt->kmsg_max_cnt)
- return -EINVAL;
- return psz_kmsg_erase(cxt, cxt->kpszs[record->id], record);
- case PSTORE_TYPE_PMSG:
- return psz_record_erase(cxt, cxt->ppsz);
- case PSTORE_TYPE_CONSOLE:
- return psz_record_erase(cxt, cxt->cpsz);
- case PSTORE_TYPE_FTRACE:
- if (record->id >= cxt->ftrace_max_cnt)
- return -EINVAL;
- return psz_record_erase(cxt, cxt->fpszs[record->id]);
- default: return -EINVAL;
- }
- }
- static void psz_write_kmsg_hdr(struct pstore_zone *zone,
- struct pstore_record *record)
- {
- struct psz_context *cxt = record->psi->data;
- struct psz_buffer *buffer = zone->buffer;
- struct psz_kmsg_header *hdr =
- (struct psz_kmsg_header *)buffer->data;
- hdr->magic = PSTORE_KMSG_HEADER_MAGIC;
- hdr->compressed = record->compressed;
- hdr->time.tv_sec = record->time.tv_sec;
- hdr->time.tv_nsec = record->time.tv_nsec;
- hdr->reason = record->reason;
- if (hdr->reason == KMSG_DUMP_OOPS)
- hdr->counter = ++cxt->oops_counter;
- else if (hdr->reason == KMSG_DUMP_PANIC)
- hdr->counter = ++cxt->panic_counter;
- else
- hdr->counter = 0;
- }
- /*
- * In case zone is broken, which may occur to MTD device, we try each zones,
- * start at cxt->kmsg_write_cnt.
- */
- static inline int notrace psz_kmsg_write_record(struct psz_context *cxt,
- struct pstore_record *record)
- {
- size_t size, hlen;
- struct pstore_zone *zone;
- unsigned int i;
- for (i = 0; i < cxt->kmsg_max_cnt; i++) {
- unsigned int zonenum, len;
- int ret;
- zonenum = (cxt->kmsg_write_cnt + i) % cxt->kmsg_max_cnt;
- zone = cxt->kpszs[zonenum];
- if (unlikely(!zone))
- return -ENOSPC;
- /* avoid destroying old data, allocate a new one */
- len = zone->buffer_size + sizeof(*zone->buffer);
- zone->oldbuf = zone->buffer;
- zone->buffer = kzalloc(len, GFP_KERNEL);
- if (!zone->buffer) {
- zone->buffer = zone->oldbuf;
- return -ENOMEM;
- }
- zone->buffer->sig = zone->oldbuf->sig;
- pr_debug("write %s to zone id %d\n", zone->name, zonenum);
- psz_write_kmsg_hdr(zone, record);
- hlen = sizeof(struct psz_kmsg_header);
- size = min_t(size_t, record->size, zone->buffer_size - hlen);
- ret = psz_zone_write(zone, FLUSH_ALL, record->buf, size, hlen);
- if (likely(!ret || ret != -ENOMSG)) {
- cxt->kmsg_write_cnt = zonenum + 1;
- cxt->kmsg_write_cnt %= cxt->kmsg_max_cnt;
- /* no need to try next zone, free last zone buffer */
- kfree(zone->oldbuf);
- zone->oldbuf = NULL;
- return ret;
- }
- pr_debug("zone %u may be broken, try next dmesg zone\n",
- zonenum);
- kfree(zone->buffer);
- zone->buffer = zone->oldbuf;
- zone->oldbuf = NULL;
- }
- return -EBUSY;
- }
- static int notrace psz_kmsg_write(struct psz_context *cxt,
- struct pstore_record *record)
- {
- int ret;
- /*
- * Explicitly only take the first part of any new crash.
- * If our buffer is larger than kmsg_bytes, this can never happen,
- * and if our buffer is smaller than kmsg_bytes, we don't want the
- * report split across multiple records.
- */
- if (record->part != 1)
- return -ENOSPC;
- if (!cxt->kpszs)
- return -ENOSPC;
- ret = psz_kmsg_write_record(cxt, record);
- if (!ret && is_on_panic()) {
- /* ensure all data are flushed to storage when panic */
- pr_debug("try to flush other dirty zones\n");
- psz_flush_all_dirty_zones(NULL);
- }
- /* always return 0 as we had handled it on buffer */
- return 0;
- }
- static int notrace psz_record_write(struct pstore_zone *zone,
- struct pstore_record *record)
- {
- size_t start, rem;
- bool is_full_data = false;
- char *buf;
- int cnt;
- if (!zone || !record)
- return -ENOSPC;
- if (atomic_read(&zone->buffer->datalen) >= zone->buffer_size)
- is_full_data = true;
- cnt = record->size;
- buf = record->buf;
- if (unlikely(cnt > zone->buffer_size)) {
- buf += cnt - zone->buffer_size;
- cnt = zone->buffer_size;
- }
- start = buffer_start(zone);
- rem = zone->buffer_size - start;
- if (unlikely(rem < cnt)) {
- psz_zone_write(zone, FLUSH_PART, buf, rem, start);
- buf += rem;
- cnt -= rem;
- start = 0;
- is_full_data = true;
- }
- atomic_set(&zone->buffer->start, cnt + start);
- psz_zone_write(zone, FLUSH_PART, buf, cnt, start);
- /**
- * psz_zone_write will set datalen as start + cnt.
- * It work if actual data length lesser than buffer size.
- * If data length greater than buffer size, pmsg will rewrite to
- * beginning of zone, which make buffer->datalen wrongly.
- * So we should reset datalen as buffer size once actual data length
- * greater than buffer size.
- */
- if (is_full_data) {
- atomic_set(&zone->buffer->datalen, zone->buffer_size);
- psz_zone_write(zone, FLUSH_META, NULL, 0, 0);
- }
- return 0;
- }
- static int notrace psz_pstore_write(struct pstore_record *record)
- {
- struct psz_context *cxt = record->psi->data;
- if (record->type == PSTORE_TYPE_DMESG &&
- record->reason == KMSG_DUMP_PANIC)
- atomic_set(&cxt->on_panic, 1);
- /*
- * if on panic, do not write except panic records
- * Fix case that panic_write prints log which wakes up console backend.
- */
- if (is_on_panic() && record->type != PSTORE_TYPE_DMESG)
- return -EBUSY;
- switch (record->type) {
- case PSTORE_TYPE_DMESG:
- return psz_kmsg_write(cxt, record);
- case PSTORE_TYPE_CONSOLE:
- return psz_record_write(cxt->cpsz, record);
- case PSTORE_TYPE_PMSG:
- return psz_record_write(cxt->ppsz, record);
- case PSTORE_TYPE_FTRACE: {
- int zonenum = smp_processor_id();
- if (!cxt->fpszs)
- return -ENOSPC;
- return psz_record_write(cxt->fpszs[zonenum], record);
- }
- default:
- return -EINVAL;
- }
- }
- static struct pstore_zone *psz_read_next_zone(struct psz_context *cxt)
- {
- struct pstore_zone *zone = NULL;
- while (cxt->kmsg_read_cnt < cxt->kmsg_max_cnt) {
- zone = cxt->kpszs[cxt->kmsg_read_cnt++];
- if (psz_ok(zone))
- return zone;
- }
- if (cxt->ftrace_read_cnt < cxt->ftrace_max_cnt)
- /*
- * No need psz_old_ok(). Let psz_ftrace_read() do so for
- * combination. psz_ftrace_read() should traverse over
- * all zones in case of some zone without data.
- */
- return cxt->fpszs[cxt->ftrace_read_cnt++];
- if (cxt->pmsg_read_cnt == 0) {
- cxt->pmsg_read_cnt++;
- zone = cxt->ppsz;
- if (psz_old_ok(zone))
- return zone;
- }
- if (cxt->console_read_cnt == 0) {
- cxt->console_read_cnt++;
- zone = cxt->cpsz;
- if (psz_old_ok(zone))
- return zone;
- }
- return NULL;
- }
- static int psz_kmsg_read_hdr(struct pstore_zone *zone,
- struct pstore_record *record)
- {
- struct psz_buffer *buffer = zone->buffer;
- struct psz_kmsg_header *hdr =
- (struct psz_kmsg_header *)buffer->data;
- if (hdr->magic != PSTORE_KMSG_HEADER_MAGIC)
- return -EINVAL;
- record->compressed = hdr->compressed;
- record->time.tv_sec = hdr->time.tv_sec;
- record->time.tv_nsec = hdr->time.tv_nsec;
- record->reason = hdr->reason;
- record->count = hdr->counter;
- return 0;
- }
- static ssize_t psz_kmsg_read(struct pstore_zone *zone,
- struct pstore_record *record)
- {
- ssize_t size, hlen = 0;
- size = buffer_datalen(zone);
- /* Clear and skip this kmsg dump record if it has no valid header */
- if (psz_kmsg_read_hdr(zone, record)) {
- atomic_set(&zone->buffer->datalen, 0);
- atomic_set(&zone->dirty, 0);
- return -ENOMSG;
- }
- size -= sizeof(struct psz_kmsg_header);
- if (!record->compressed) {
- char *buf = kasprintf(GFP_KERNEL, "%s: Total %d times\n",
- kmsg_dump_reason_str(record->reason),
- record->count);
- hlen = strlen(buf);
- record->buf = krealloc(buf, hlen + size, GFP_KERNEL);
- if (!record->buf) {
- kfree(buf);
- return -ENOMEM;
- }
- } else {
- record->buf = kmalloc(size, GFP_KERNEL);
- if (!record->buf)
- return -ENOMEM;
- }
- size = psz_zone_read_buffer(zone, record->buf + hlen, size,
- sizeof(struct psz_kmsg_header));
- if (unlikely(size < 0)) {
- kfree(record->buf);
- return -ENOMSG;
- }
- return size + hlen;
- }
- /* try to combine all ftrace zones */
- static ssize_t psz_ftrace_read(struct pstore_zone *zone,
- struct pstore_record *record)
- {
- struct psz_context *cxt;
- struct psz_buffer *buf;
- int ret;
- if (!zone || !record)
- return -ENOSPC;
- if (!psz_old_ok(zone))
- goto out;
- buf = (struct psz_buffer *)zone->oldbuf;
- if (!buf)
- return -ENOMSG;
- ret = pstore_ftrace_combine_log(&record->buf, &record->size,
- (char *)buf->data, atomic_read(&buf->datalen));
- if (unlikely(ret))
- return ret;
- out:
- cxt = record->psi->data;
- if (cxt->ftrace_read_cnt < cxt->ftrace_max_cnt)
- /* then, read next ftrace zone */
- return -ENOMSG;
- record->id = 0;
- return record->size ? record->size : -ENOMSG;
- }
- static ssize_t psz_record_read(struct pstore_zone *zone,
- struct pstore_record *record)
- {
- size_t len;
- struct psz_buffer *buf;
- if (!zone || !record)
- return -ENOSPC;
- buf = (struct psz_buffer *)zone->oldbuf;
- if (!buf)
- return -ENOMSG;
- len = atomic_read(&buf->datalen);
- record->buf = kmalloc(len, GFP_KERNEL);
- if (!record->buf)
- return -ENOMEM;
- if (unlikely(psz_zone_read_oldbuf(zone, record->buf, len, 0))) {
- kfree(record->buf);
- return -ENOMSG;
- }
- return len;
- }
- static ssize_t psz_pstore_read(struct pstore_record *record)
- {
- struct psz_context *cxt = record->psi->data;
- ssize_t (*readop)(struct pstore_zone *zone,
- struct pstore_record *record);
- struct pstore_zone *zone;
- ssize_t ret;
- /* before read, we must recover from storage */
- ret = psz_recovery(cxt);
- if (ret)
- return ret;
- next_zone:
- zone = psz_read_next_zone(cxt);
- if (!zone)
- return 0;
- record->type = zone->type;
- switch (record->type) {
- case PSTORE_TYPE_DMESG:
- readop = psz_kmsg_read;
- record->id = cxt->kmsg_read_cnt - 1;
- break;
- case PSTORE_TYPE_FTRACE:
- readop = psz_ftrace_read;
- break;
- case PSTORE_TYPE_CONSOLE:
- case PSTORE_TYPE_PMSG:
- readop = psz_record_read;
- break;
- default:
- goto next_zone;
- }
- ret = readop(zone, record);
- if (ret == -ENOMSG)
- goto next_zone;
- return ret;
- }
- static struct psz_context pstore_zone_cxt = {
- .pstore_zone_info_lock =
- __MUTEX_INITIALIZER(pstore_zone_cxt.pstore_zone_info_lock),
- .recovered = ATOMIC_INIT(0),
- .on_panic = ATOMIC_INIT(0),
- .pstore = {
- .owner = THIS_MODULE,
- .open = psz_pstore_open,
- .read = psz_pstore_read,
- .write = psz_pstore_write,
- .erase = psz_pstore_erase,
- },
- };
- static void psz_free_zone(struct pstore_zone **pszone)
- {
- struct pstore_zone *zone = *pszone;
- if (!zone)
- return;
- kfree(zone->buffer);
- kfree(zone);
- *pszone = NULL;
- }
- static void psz_free_zones(struct pstore_zone ***pszones, unsigned int *cnt)
- {
- struct pstore_zone **zones = *pszones;
- if (!zones)
- return;
- while (*cnt > 0) {
- (*cnt)--;
- psz_free_zone(&(zones[*cnt]));
- }
- kfree(zones);
- *pszones = NULL;
- }
- static void psz_free_all_zones(struct psz_context *cxt)
- {
- if (cxt->kpszs)
- psz_free_zones(&cxt->kpszs, &cxt->kmsg_max_cnt);
- if (cxt->ppsz)
- psz_free_zone(&cxt->ppsz);
- if (cxt->cpsz)
- psz_free_zone(&cxt->cpsz);
- if (cxt->fpszs)
- psz_free_zones(&cxt->fpszs, &cxt->ftrace_max_cnt);
- }
- static struct pstore_zone *psz_init_zone(enum pstore_type_id type,
- loff_t *off, size_t size)
- {
- struct pstore_zone_info *info = pstore_zone_cxt.pstore_zone_info;
- struct pstore_zone *zone;
- const char *name = pstore_type_to_name(type);
- if (!size)
- return NULL;
- if (*off + size > info->total_size) {
- pr_err("no room for %s (0x%zx@0x%llx over 0x%lx)\n",
- name, size, *off, info->total_size);
- return ERR_PTR(-ENOMEM);
- }
- zone = kzalloc(sizeof(struct pstore_zone), GFP_KERNEL);
- if (!zone)
- return ERR_PTR(-ENOMEM);
- zone->buffer = kmalloc(size, GFP_KERNEL);
- if (!zone->buffer) {
- kfree(zone);
- return ERR_PTR(-ENOMEM);
- }
- memset(zone->buffer, 0xFF, size);
- zone->off = *off;
- zone->name = name;
- zone->type = type;
- zone->buffer_size = size - sizeof(struct psz_buffer);
- zone->buffer->sig = type ^ PSZ_SIG;
- zone->oldbuf = NULL;
- atomic_set(&zone->dirty, 0);
- atomic_set(&zone->buffer->datalen, 0);
- atomic_set(&zone->buffer->start, 0);
- *off += size;
- pr_debug("pszone %s: off 0x%llx, %zu header, %zu data\n", zone->name,
- zone->off, sizeof(*zone->buffer), zone->buffer_size);
- return zone;
- }
- static struct pstore_zone **psz_init_zones(enum pstore_type_id type,
- loff_t *off, size_t total_size, ssize_t record_size,
- unsigned int *cnt)
- {
- struct pstore_zone_info *info = pstore_zone_cxt.pstore_zone_info;
- struct pstore_zone **zones, *zone;
- const char *name = pstore_type_to_name(type);
- int c, i;
- *cnt = 0;
- if (!total_size || !record_size)
- return NULL;
- if (*off + total_size > info->total_size) {
- pr_err("no room for zones %s (0x%zx@0x%llx over 0x%lx)\n",
- name, total_size, *off, info->total_size);
- return ERR_PTR(-ENOMEM);
- }
- c = total_size / record_size;
- zones = kcalloc(c, sizeof(*zones), GFP_KERNEL);
- if (!zones) {
- pr_err("allocate for zones %s failed\n", name);
- return ERR_PTR(-ENOMEM);
- }
- memset(zones, 0, c * sizeof(*zones));
- for (i = 0; i < c; i++) {
- zone = psz_init_zone(type, off, record_size);
- if (!zone || IS_ERR(zone)) {
- pr_err("initialize zones %s failed\n", name);
- psz_free_zones(&zones, &i);
- return (void *)zone;
- }
- zones[i] = zone;
- }
- *cnt = c;
- return zones;
- }
- static int psz_alloc_zones(struct psz_context *cxt)
- {
- struct pstore_zone_info *info = cxt->pstore_zone_info;
- loff_t off = 0;
- int err;
- size_t off_size = 0;
- off_size += info->pmsg_size;
- cxt->ppsz = psz_init_zone(PSTORE_TYPE_PMSG, &off, info->pmsg_size);
- if (IS_ERR(cxt->ppsz)) {
- err = PTR_ERR(cxt->ppsz);
- cxt->ppsz = NULL;
- goto free_out;
- }
- off_size += info->console_size;
- cxt->cpsz = psz_init_zone(PSTORE_TYPE_CONSOLE, &off,
- info->console_size);
- if (IS_ERR(cxt->cpsz)) {
- err = PTR_ERR(cxt->cpsz);
- cxt->cpsz = NULL;
- goto free_out;
- }
- off_size += info->ftrace_size;
- cxt->fpszs = psz_init_zones(PSTORE_TYPE_FTRACE, &off,
- info->ftrace_size,
- info->ftrace_size / nr_cpu_ids,
- &cxt->ftrace_max_cnt);
- if (IS_ERR(cxt->fpszs)) {
- err = PTR_ERR(cxt->fpszs);
- cxt->fpszs = NULL;
- goto free_out;
- }
- cxt->kpszs = psz_init_zones(PSTORE_TYPE_DMESG, &off,
- info->total_size - off_size,
- info->kmsg_size, &cxt->kmsg_max_cnt);
- if (IS_ERR(cxt->kpszs)) {
- err = PTR_ERR(cxt->kpszs);
- cxt->kpszs = NULL;
- goto free_out;
- }
- return 0;
- free_out:
- psz_free_all_zones(cxt);
- return err;
- }
- /**
- * register_pstore_zone() - register to pstore/zone
- *
- * @info: back-end driver information. See &struct pstore_zone_info.
- *
- * Only one back-end at one time.
- *
- * Return: 0 on success, others on failure.
- */
- int register_pstore_zone(struct pstore_zone_info *info)
- {
- int err = -EINVAL;
- struct psz_context *cxt = &pstore_zone_cxt;
- if (info->total_size < 4096) {
- pr_warn("total_size must be >= 4096\n");
- return -EINVAL;
- }
- if (!info->kmsg_size && !info->pmsg_size && !info->console_size &&
- !info->ftrace_size) {
- pr_warn("at least one record size must be non-zero\n");
- return -EINVAL;
- }
- if (!info->name || !info->name[0])
- return -EINVAL;
- #define check_size(name, size) { \
- if (info->name > 0 && info->name < (size)) { \
- pr_err(#name " must be over %d\n", (size)); \
- return -EINVAL; \
- } \
- if (info->name & (size - 1)) { \
- pr_err(#name " must be a multiple of %d\n", \
- (size)); \
- return -EINVAL; \
- } \
- }
- check_size(total_size, 4096);
- check_size(kmsg_size, SECTOR_SIZE);
- check_size(pmsg_size, SECTOR_SIZE);
- check_size(console_size, SECTOR_SIZE);
- check_size(ftrace_size, SECTOR_SIZE);
- #undef check_size
- /*
- * the @read and @write must be applied.
- * if no @read, pstore may mount failed.
- * if no @write, pstore do not support to remove record file.
- */
- if (!info->read || !info->write) {
- pr_err("no valid general read/write interface\n");
- return -EINVAL;
- }
- mutex_lock(&cxt->pstore_zone_info_lock);
- if (cxt->pstore_zone_info) {
- pr_warn("'%s' already loaded: ignoring '%s'\n",
- cxt->pstore_zone_info->name, info->name);
- mutex_unlock(&cxt->pstore_zone_info_lock);
- return -EBUSY;
- }
- cxt->pstore_zone_info = info;
- pr_debug("register %s with properties:\n", info->name);
- pr_debug("\ttotal size : %ld Bytes\n", info->total_size);
- pr_debug("\tkmsg size : %ld Bytes\n", info->kmsg_size);
- pr_debug("\tpmsg size : %ld Bytes\n", info->pmsg_size);
- pr_debug("\tconsole size : %ld Bytes\n", info->console_size);
- pr_debug("\tftrace size : %ld Bytes\n", info->ftrace_size);
- err = psz_alloc_zones(cxt);
- if (err) {
- pr_err("alloc zones failed\n");
- goto fail_out;
- }
- if (info->kmsg_size) {
- cxt->pstore.bufsize = cxt->kpszs[0]->buffer_size -
- sizeof(struct psz_kmsg_header);
- cxt->pstore.buf = kzalloc(cxt->pstore.bufsize, GFP_KERNEL);
- if (!cxt->pstore.buf) {
- err = -ENOMEM;
- goto fail_free;
- }
- }
- cxt->pstore.data = cxt;
- pr_info("registered %s as backend for", info->name);
- cxt->pstore.max_reason = info->max_reason;
- cxt->pstore.name = info->name;
- if (info->kmsg_size) {
- cxt->pstore.flags |= PSTORE_FLAGS_DMESG;
- pr_cont(" kmsg(%s",
- kmsg_dump_reason_str(cxt->pstore.max_reason));
- if (cxt->pstore_zone_info->panic_write)
- pr_cont(",panic_write");
- pr_cont(")");
- }
- if (info->pmsg_size) {
- cxt->pstore.flags |= PSTORE_FLAGS_PMSG;
- pr_cont(" pmsg");
- }
- if (info->console_size) {
- cxt->pstore.flags |= PSTORE_FLAGS_CONSOLE;
- pr_cont(" console");
- }
- if (info->ftrace_size) {
- cxt->pstore.flags |= PSTORE_FLAGS_FTRACE;
- pr_cont(" ftrace");
- }
- pr_cont("\n");
- err = pstore_register(&cxt->pstore);
- if (err) {
- pr_err("registering with pstore failed\n");
- goto fail_free;
- }
- mutex_unlock(&pstore_zone_cxt.pstore_zone_info_lock);
- return 0;
- fail_free:
- kfree(cxt->pstore.buf);
- cxt->pstore.buf = NULL;
- cxt->pstore.bufsize = 0;
- psz_free_all_zones(cxt);
- fail_out:
- pstore_zone_cxt.pstore_zone_info = NULL;
- mutex_unlock(&pstore_zone_cxt.pstore_zone_info_lock);
- return err;
- }
- EXPORT_SYMBOL_GPL(register_pstore_zone);
- /**
- * unregister_pstore_zone() - unregister to pstore/zone
- *
- * @info: back-end driver information. See struct pstore_zone_info.
- */
- void unregister_pstore_zone(struct pstore_zone_info *info)
- {
- struct psz_context *cxt = &pstore_zone_cxt;
- mutex_lock(&cxt->pstore_zone_info_lock);
- if (!cxt->pstore_zone_info) {
- mutex_unlock(&cxt->pstore_zone_info_lock);
- return;
- }
- /* Stop incoming writes from pstore. */
- pstore_unregister(&cxt->pstore);
- /* Flush any pending writes. */
- psz_flush_all_dirty_zones(NULL);
- flush_delayed_work(&psz_cleaner);
- /* Clean up allocations. */
- kfree(cxt->pstore.buf);
- cxt->pstore.buf = NULL;
- cxt->pstore.bufsize = 0;
- cxt->pstore_zone_info = NULL;
- psz_free_all_zones(cxt);
- /* Clear counters and zone state. */
- cxt->oops_counter = 0;
- cxt->panic_counter = 0;
- atomic_set(&cxt->recovered, 0);
- atomic_set(&cxt->on_panic, 0);
- mutex_unlock(&cxt->pstore_zone_info_lock);
- }
- EXPORT_SYMBOL_GPL(unregister_pstore_zone);
- MODULE_LICENSE("GPL");
- MODULE_AUTHOR("WeiXiong Liao <liaoweixiong@allwinnertech.com>");
- MODULE_AUTHOR("Kees Cook <keescook@chromium.org>");
- MODULE_DESCRIPTION("Storage Manager for pstore/blk");
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