* [RFC v8 1/5] pstore/blk: new support logger for block devices
2019-02-13 14:07 [RFC v8 0/5] pstore/block: new support logger for block devices liaoweixiong
@ 2019-02-13 14:07 ` liaoweixiong
2019-02-13 14:07 ` [RFC v8 2/5] dt-bindings: pstore-block: new support for blkoops liaoweixiong
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: liaoweixiong @ 2019-02-13 14:07 UTC (permalink / raw)
To: Kees Cook, Anton Vorontsov, Colin Cross, Tony Luck,
Jonathan Corbet, Rob Herring, Mark Rutland, liaoweixiong,
Mauro Carvalho Chehab, David S. Miller, Greg Kroah-Hartman,
Nicolas Ferre, Arnd Bergmann
Cc: linux-doc, linux-kernel, devicetree
pstore_blk is similar to pstore_ram, but dump log to block devices
rather than persistent ram.
Why should we need pstore_blk?
1. Most embedded intelligent equipment have no persistent ram, which
increases costs. We perfer to cheaper solutions, like block devices.
In fact, there is already a sample for block device logger in driver
MTD (drivers/mtd/mtdoops.c).
2. Do not any equipment have battery, which means that it lost all data
on general ram if power failure. Pstore has little to do for these
equipments.
pstore_blk can only dump Oops/Panic log to block devices. It only
supports dmesg now. To make pstore_blk work, the block driver should
provide the path of a block partition device (/dev/XXXX) and the
read/write apis when on panic.
pstore_blk begins at 'blkz_register', by witch block device can register
a block partition to pstore_blk. Then pstore_blk divide and manage the
partition as zones, which is similar to pstore_ram.
Recommend that, block driver register pstore_blk after block device is
ready.
pstore_blk works well on allwinner(sunxi) platform.
Signed-off-by: liaoweixiong <liaoweixiong@allwinnertech.com>
---
fs/pstore/Kconfig | 7 +
fs/pstore/Makefile | 3 +
fs/pstore/blkzone.c | 954 +++++++++++++++++++++++++++++++++++++++++++++
include/linux/pstore_blk.h | 61 +++
4 files changed, 1025 insertions(+)
create mode 100644 fs/pstore/blkzone.c
create mode 100644 include/linux/pstore_blk.h
diff --git a/fs/pstore/Kconfig b/fs/pstore/Kconfig
index 8b3ba27..a881c53 100644
--- a/fs/pstore/Kconfig
+++ b/fs/pstore/Kconfig
@@ -152,3 +152,10 @@ config PSTORE_RAM
"ramoops.ko".
For more information, see Documentation/admin-guide/ramoops.rst.
+
+config PSTORE_BLK
+ tristate "Log panic/oops to a block device"
+ depends on PSTORE
+ help
+ This enables panic and oops message to be logged to a block dev
+ where it can be read back at some later point.
diff --git a/fs/pstore/Makefile b/fs/pstore/Makefile
index 967b589..0ee2fc8 100644
--- a/fs/pstore/Makefile
+++ b/fs/pstore/Makefile
@@ -12,3 +12,6 @@ pstore-$(CONFIG_PSTORE_PMSG) += pmsg.o
ramoops-objs += ram.o ram_core.o
obj-$(CONFIG_PSTORE_RAM) += ramoops.o
+
+obj-$(CONFIG_PSTORE_BLK) += pstore_blk.o
+pstore_blk-y += blkzone.o
diff --git a/fs/pstore/blkzone.c b/fs/pstore/blkzone.c
new file mode 100644
index 0000000..aca8c2a
--- /dev/null
+++ b/fs/pstore/blkzone.c
@@ -0,0 +1,954 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *
+ * blkzone.c: Block device Oops/Panic logger
+ *
+ * Copyright (C) 2019 liaoweixiong <liaoweixiong@gallwinnertech.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#define MODNAME "pstore-blk"
+#define pr_fmt(fmt) MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/blkdev.h>
+#include <linux/pstore.h>
+#include <linux/mount.h>
+#include <linux/printk.h>
+#include <linux/fs.h>
+#include <linux/pstore_blk.h>
+
+/**
+ * struct blkz_head - head of zone to flush to storage
+ *
+ * @sig: signature to indicate header (BLK_SIG xor BLKZONE-type value)
+ * @datalen: length of data in @data
+ * @data: zone data.
+ */
+struct blkz_buffer {
+#define BLK_SIG (0x43474244) /* DBGC */
+ uint32_t sig;
+ atomic_t datalen;
+ uint8_t data[];
+};
+
+/**
+ * struct blkz_dmesg_header: dmesg information
+ *
+ * @magic: magic num for dmesg header
+ * @time: trigger time
+ * @compressed: whether conpressed
+ * @count: oops/panic counter
+ * @reason: identify oops or panic
+ */
+struct blkz_dmesg_header {
+#define DMESG_HEADER_MAGIC 0x4dfc3ae5
+ uint32_t magic;
+ struct timespec64 time;
+ bool compressed;
+ uint32_t counter;
+ enum kmsg_dump_reason reason;
+ uint8_t data[0];
+};
+
+/**
+ * struct blkz_zone - zone information
+ * @off:
+ * zone offset of partition
+ * @type:
+ * frontent type for this zone
+ * @name:
+ * frontent name for this zone
+ * @buffer:
+ * pointer to data buffer managed by this zone
+ * @buffer_size:
+ * bytes in @buffer->data
+ * @should_recover:
+ * should recover from storage
+ * @dirty:
+ * mark whether the data in @buffer are dirty (not flush to storage yet)
+ */
+struct blkz_zone {
+ unsigned long off;
+ const char *name;
+ enum pstore_type_id type;
+
+ struct blkz_buffer *buffer;
+ size_t buffer_size;
+ bool should_recover;
+ atomic_t dirty;
+};
+
+struct blkz_context {
+ struct blkz_zone **dbzs; /* dmesg block zones */
+ unsigned int dmesg_max_cnt;
+ unsigned int dmesg_read_cnt;
+ unsigned int dmesg_write_cnt;
+ /**
+ * the counter should be recovered when do recovery
+ * It records the oops/panic times after burning rather than booting.
+ */
+ unsigned int oops_counter;
+ unsigned int panic_counter;
+ atomic_t blkdev_up;
+ atomic_t recovery;
+ atomic_t on_panic;
+
+ /*
+ * bzinfo_lock just protects "bzinfo" during calls to
+ * blkz_register/blkz_unregister
+ */
+ spinlock_t bzinfo_lock;
+ struct blkz_info *bzinfo;
+ struct pstore_info pstore;
+};
+static struct blkz_context blkz_cxt;
+
+enum blkz_flush_mode {
+ FLUSH_NONE = 0,
+ FLUSH_PART,
+ FLUSH_META,
+ FLUSH_ALL,
+};
+
+static inline int buffer_datalen(struct blkz_zone *zone)
+{
+ return atomic_read(&zone->buffer->datalen);
+}
+
+static inline bool is_on_panic(void)
+{
+ struct blkz_context *cxt = &blkz_cxt;
+
+ return atomic_read(&cxt->on_panic);
+}
+
+static inline bool is_blkdev_up(void)
+{
+ struct blkz_context *cxt = &blkz_cxt;
+ const char *devpath = cxt->bzinfo->part_path;
+
+ if (atomic_read(&cxt->blkdev_up))
+ return true;
+ if (is_on_panic())
+ goto set_up;
+ if (devpath && !name_to_dev_t(devpath))
+ return false;
+set_up:
+ atomic_set(&cxt->blkdev_up, 1);
+ return true;
+}
+
+static int blkz_zone_read(struct blkz_zone *zone, char *buf,
+ size_t len, unsigned long off)
+{
+ if (!buf || !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 0;
+}
+
+static int blkz_zone_write(struct blkz_zone *zone,
+ enum blkz_flush_mode flush_mode, const char *buf,
+ size_t len, unsigned long off)
+{
+ struct blkz_info *info = blkz_cxt.bzinfo;
+ ssize_t wcnt;
+ 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 (flush_mode != FLUSH_META && flush_mode != FLUSH_NONE) {
+ if (buf && zone->buffer)
+ memcpy(zone->buffer->data + off, buf, wlen);
+ atomic_set(&zone->buffer->datalen, wlen + off);
+ }
+
+ if (!is_blkdev_up())
+ goto set_dirty;
+
+ writeop = is_on_panic() ? info->panic_write : info->write;
+ if (!writeop)
+ return -EINVAL;
+
+ switch (flush_mode) {
+ case FLUSH_NONE:
+ return 0;
+ case FLUSH_PART:
+ wcnt = writeop((const char *)zone->buffer->data + off, wlen,
+ zone->off + sizeof(*zone->buffer) + off);
+ if (wcnt != wlen)
+ goto set_dirty;
+ case FLUSH_META:
+ wlen = sizeof(struct blkz_buffer);
+ wcnt = writeop((const char *)zone->buffer, wlen, zone->off);
+ if (wcnt != wlen)
+ goto set_dirty;
+ break;
+ case FLUSH_ALL:
+ wlen = buffer_datalen(zone) + sizeof(*zone->buffer);
+ wcnt = writeop((const char *)zone->buffer, wlen, zone->off);
+ if (wcnt != wlen)
+ goto set_dirty;
+ break;
+ }
+
+ return 0;
+set_dirty:
+ atomic_set(&zone->dirty, true);
+ return -EBUSY;
+}
+
+/*
+ * blkz_move_zone: move data from a old zone to a new zone
+ *
+ * @old: the old zone
+ * @new: the new zone
+ *
+ * NOTE:
+ * Call blkz_zone_write to copy and flush data. If it failed, we
+ * should reset new->dirty, because the new zone not really dirty.
+ */
+static int blkz_move_zone(struct blkz_zone *old, struct blkz_zone *new)
+{
+ const char *data = (const char *)old->buffer->data;
+ int ret;
+
+ ret = blkz_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 int blkz_recover_dmesg_data(struct blkz_context *cxt)
+{
+ struct blkz_info *info = cxt->bzinfo;
+ struct blkz_zone *zone = NULL;
+ struct blkz_buffer *buf;
+ unsigned long i;
+ ssize_t (*readop)(char *buf, size_t bytes, loff_t pos);
+ ssize_t rcnt;
+
+ readop = is_on_panic() ? info->panic_read : info->read;
+ if (!readop)
+ return -EINVAL;
+
+ for (i = 0; i < cxt->dmesg_max_cnt; i++) {
+ zone = cxt->dbzs[i];
+ if (unlikely(!zone))
+ return -EINVAL;
+ if (atomic_read(&zone->dirty)) {
+ unsigned int wcnt = cxt->dmesg_write_cnt;
+ struct blkz_zone *new = cxt->dbzs[wcnt];
+ int ret;
+
+ ret = blkz_move_zone(zone, new);
+ if (ret) {
+ pr_err("move zone from %lu to %d failed\n",
+ i, wcnt);
+ return ret;
+ }
+ cxt->dmesg_write_cnt = (wcnt + 1) % cxt->dmesg_max_cnt;
+ }
+ if (!zone->should_recover)
+ continue;
+ buf = zone->buffer;
+ rcnt = readop((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;
+}
+
+/**
+ * blkz_recover_dmesg_meta: recover metadata of dmesg
+ *
+ * Recover metadata as follow:
+ * @cxt->dmesg_write_cnt
+ * @cxt->oops_counter
+ * @cxt->panic_counter
+ */
+static int blkz_recover_dmesg_meta(struct blkz_context *cxt)
+{
+ struct blkz_info *info = cxt->bzinfo;
+ struct blkz_zone *zone;
+ size_t rcnt, len;
+ struct blkz_buffer *buf;
+ struct blkz_dmesg_header *hdr;
+ ssize_t (*readop)(char *buf, size_t bytes, loff_t pos);
+ struct timespec64 time = {0};
+ 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};
+
+ readop = is_on_panic() ? info->panic_read : info->read;
+ if (!readop)
+ return -EINVAL;
+
+ len = sizeof(*buf) + sizeof(*hdr);
+ buf = (struct blkz_buffer *)buffer_header;
+ for (i = 0; i < cxt->dmesg_max_cnt; i++) {
+ zone = cxt->dbzs[i];
+ if (unlikely(!zone))
+ return -EINVAL;
+
+ rcnt = readop((char *)buf, len, zone->off);
+ if (rcnt != len)
+ return (int)rcnt < 0 ? (int)rcnt : -EIO;
+
+ /*
+ * If sig NOT match, it means this zone never used before,
+ * because we write one by one, and we never modify sig even
+ * when erase. So, we do not need to check next one.
+ */
+ if (buf->sig != zone->buffer->sig) {
+ cxt->dmesg_write_cnt = i;
+ pr_debug("no valid data in dmesg zone %lu\n", i);
+ break;
+ }
+
+ if (zone->buffer_size < atomic_read(&buf->datalen)) {
+ pr_info("found overtop zone: %s: id %lu, off %lu, size %zu\n",
+ zone->name, i, zone->off,
+ zone->buffer_size);
+ continue;
+ }
+
+ hdr = (struct blkz_dmesg_header *)buf->data;
+ if (hdr->magic != DMESG_HEADER_MAGIC) {
+ pr_info("found invalid zone: %s: id %lu, off %lu, 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->dmesg_write_cnt = (i + 1) % cxt->dmesg_max_cnt;
+ }
+
+ if (hdr->reason == KMSG_DUMP_OOPS)
+ cxt->oops_counter =
+ max(cxt->oops_counter, hdr->counter);
+ else
+ cxt->panic_counter =
+ max(cxt->panic_counter, hdr->counter);
+
+ if (!atomic_read(&buf->datalen)) {
+ pr_debug("found erased zone: %s: id %ld, off %lu, 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 %ld, off %lu, size %zu, datalen %d\n",
+ zone->name, i, zone->off,
+ zone->buffer_size, atomic_read(&buf->datalen));
+ }
+
+ return 0;
+}
+
+static int blkz_recover_dmesg(struct blkz_context *cxt)
+{
+ int ret;
+
+ if (!cxt->dbzs)
+ return 0;
+
+ ret = blkz_recover_dmesg_meta(cxt);
+ if (ret)
+ goto recover_fail;
+
+ ret = blkz_recover_dmesg_data(cxt);
+ if (ret)
+ goto recover_fail;
+
+ return 0;
+recover_fail:
+ pr_debug("recover dmesg failed\n");
+ return ret;
+}
+
+static inline int blkz_recovery(struct blkz_context *cxt)
+{
+ int ret = -EBUSY;
+
+ if (atomic_read(&cxt->recovery))
+ return 0;
+
+ if (!is_blkdev_up())
+ goto recover_fail;
+
+ ret = blkz_recover_dmesg(cxt);
+ if (ret)
+ goto recover_fail;
+
+ atomic_set(&cxt->recovery, 1);
+ pr_debug("recover end!\n");
+ return 0;
+
+recover_fail:
+ pr_debug("recovery failed, handle buffer\n");
+ return ret;
+}
+
+static int blkz_pstore_open(struct pstore_info *psi)
+{
+ struct blkz_context *cxt = psi->data;
+
+ cxt->dmesg_read_cnt = 0;
+ return 0;
+}
+
+static inline bool blkz_ok(struct blkz_zone *zone)
+{
+ if (!zone || !zone->buffer || !buffer_datalen(zone))
+ return false;
+ return true;
+}
+
+static int blkz_pstore_erase(struct pstore_record *record)
+{
+ struct blkz_context *cxt = record->psi->data;
+ struct blkz_zone *zone = NULL;
+
+ if (record->type == PSTORE_TYPE_DMESG)
+ zone = cxt->dbzs[record->id];
+ if (!blkz_ok(zone))
+ return 0;
+
+ atomic_set(&zone->buffer->datalen, 0);
+ return blkz_zone_write(zone, FLUSH_META, NULL, 0, 0);
+}
+
+static void blkz_write_kmsg_hdr(struct blkz_zone *zone,
+ struct pstore_record *record)
+{
+ struct blkz_context *cxt = record->psi->data;
+ struct blkz_buffer *buffer = zone->buffer;
+ struct blkz_dmesg_header *hdr =
+ (struct blkz_dmesg_header *)buffer->data;
+
+ hdr->magic = DMESG_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
+ hdr->counter = ++cxt->panic_counter;
+}
+
+static int notrace blkz_dmesg_write(struct blkz_context *cxt,
+ struct pstore_record *record)
+{
+ struct blkz_info *info = cxt->bzinfo;
+ struct blkz_zone *zone;
+ size_t size, hlen;
+
+ /*
+ * Out of the various dmesg dump types, pstore/blk is currently designed
+ * to only store crash logs, rather than storing general kernel logs.
+ */
+ if (record->reason != KMSG_DUMP_OOPS &&
+ record->reason != KMSG_DUMP_PANIC)
+ return -EINVAL;
+
+ /* Skip Oopes when configured to do so. */
+ if (record->reason == KMSG_DUMP_OOPS && !info->dump_oops)
+ return -EINVAL;
+
+ /*
+ * 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->dbzs)
+ return -ENOSPC;
+
+ zone = cxt->dbzs[cxt->dmesg_write_cnt];
+ if (!zone)
+ return -ENOSPC;
+
+ blkz_write_kmsg_hdr(zone, record);
+ hlen = sizeof(struct blkz_dmesg_header);
+ size = record->size;
+ if (size + hlen > zone->buffer_size)
+ size = zone->buffer_size - hlen;
+ blkz_zone_write(zone, FLUSH_ALL, record->buf, size, hlen);
+
+ pr_debug("write %s to zone id %d\n", zone->name, cxt->dmesg_write_cnt);
+ cxt->dmesg_write_cnt = (cxt->dmesg_write_cnt + 1) % cxt->dmesg_max_cnt;
+ return 0;
+}
+
+static int notrace blkz_pstore_write(struct pstore_record *record)
+{
+ struct blkz_context *cxt = record->psi->data;
+
+ if (record->type == PSTORE_TYPE_DMESG &&
+ record->reason == KMSG_DUMP_PANIC)
+ atomic_set(&cxt->on_panic, 1);
+
+ /*
+ * before write, we must recover from storage.
+ * if recover failed, handle buffer
+ */
+ blkz_recovery(cxt);
+
+ switch (record->type) {
+ case PSTORE_TYPE_DMESG:
+ return blkz_dmesg_write(cxt, record);
+ default:
+ return -EINVAL;
+ }
+}
+
+#define READ_NEXT_ZONE ((ssize_t)(-1024))
+static struct blkz_zone *blkz_read_next_zone(struct blkz_context *cxt)
+{
+ struct blkz_zone *zone = NULL;
+
+ while (cxt->dmesg_read_cnt < cxt->dmesg_max_cnt) {
+ zone = cxt->dbzs[cxt->dmesg_read_cnt++];
+ if (blkz_ok(zone))
+ return zone;
+ }
+
+ return NULL;
+}
+
+static int blkz_read_dmesg_hdr(struct blkz_zone *zone,
+ struct pstore_record *record)
+{
+ struct blkz_buffer *buffer = zone->buffer;
+ struct blkz_dmesg_header *hdr =
+ (struct blkz_dmesg_header *)buffer->data;
+
+ if (hdr->magic != DMESG_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 blkz_dmesg_read(struct blkz_zone *zone,
+ struct pstore_record *record)
+{
+ size_t size, hlen = 0;
+
+ size = buffer_datalen(zone);
+ /* Clear and skip this DMESG record if it has no valid header */
+ if (blkz_read_dmesg_hdr(zone, record)) {
+ atomic_set(&zone->buffer->datalen, 0);
+ atomic_set(&zone->dirty, 0);
+ return READ_NEXT_ZONE;
+ }
+ size -= sizeof(struct blkz_dmesg_header);
+
+ if (!record->compressed) {
+ char *buf = kasprintf(GFP_KERNEL,
+ "%s: Total %d times\n",
+ record->reason == KMSG_DUMP_OOPS ? "Oops" :
+ "Panic", 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;
+ }
+
+ if (unlikely(blkz_zone_read(zone, record->buf + hlen, size,
+ sizeof(struct blkz_dmesg_header)) < 0)) {
+ kfree(record->buf);
+ return READ_NEXT_ZONE;
+ }
+
+ return size + hlen;
+}
+
+static ssize_t blkz_pstore_read(struct pstore_record *record)
+{
+ struct blkz_context *cxt = record->psi->data;
+ ssize_t (*blkz_read)(struct blkz_zone *zone,
+ struct pstore_record *record);
+ struct blkz_zone *zone;
+ ssize_t ret;
+
+ /*
+ * before read, we must recover from storage.
+ * if recover failed, handle buffer
+ */
+ blkz_recovery(cxt);
+
+next_zone:
+ zone = blkz_read_next_zone(cxt);
+ if (!zone)
+ return 0;
+
+ record->type = zone->type;
+ switch (record->type) {
+ case PSTORE_TYPE_DMESG:
+ blkz_read = blkz_dmesg_read;
+ record->id = cxt->dmesg_read_cnt - 1;
+ break;
+ default:
+ goto next_zone;
+ }
+
+ ret = blkz_read(zone, record);
+ if (ret == READ_NEXT_ZONE)
+ goto next_zone;
+ return ret;
+}
+
+static struct blkz_context blkz_cxt = {
+ .bzinfo_lock = __SPIN_LOCK_UNLOCKED(blkz_cxt.bzinfo_lock),
+ .blkdev_up = ATOMIC_INIT(0),
+ .recovery = ATOMIC_INIT(0),
+ .on_panic = ATOMIC_INIT(0),
+ .pstore = {
+ .owner = THIS_MODULE,
+ .name = MODNAME,
+ .open = blkz_pstore_open,
+ .read = blkz_pstore_read,
+ .write = blkz_pstore_write,
+ .erase = blkz_pstore_erase,
+ },
+};
+
+static ssize_t blkz_default_general_read(char *buf, size_t bytes, loff_t pos)
+{
+ struct blkz_context *cxt = &blkz_cxt;
+ const char *devpath = cxt->bzinfo->part_path;
+ struct file *filp;
+ ssize_t ret;
+
+ if (!devpath)
+ return -EINVAL;
+
+ if (!is_blkdev_up())
+ return -EBUSY;
+
+ filp = filp_open(devpath, O_RDONLY, 0);
+ if (IS_ERR(filp)) {
+ pr_debug("open %s failed, maybe unready\n", devpath);
+ return -EACCES;
+ }
+ ret = kernel_read(filp, buf, bytes, &pos);
+ filp_close(filp, NULL);
+
+ return ret;
+}
+
+static ssize_t blkz_default_general_write(const char *buf, size_t bytes,
+ loff_t pos)
+{
+ struct blkz_context *cxt = &blkz_cxt;
+ const char *devpath = cxt->bzinfo->part_path;
+ struct file *filp;
+ ssize_t ret;
+
+ if (!devpath)
+ return -EINVAL;
+
+ if (!is_blkdev_up())
+ return -EBUSY;
+
+ filp = filp_open(devpath, O_WRONLY, 0);
+ if (IS_ERR(filp)) {
+ pr_debug("open %s failed, maybe unready\n", devpath);
+ return -EACCES;
+ }
+ ret = kernel_write(filp, buf, bytes, &pos);
+ vfs_fsync(filp, 0);
+ filp_close(filp, NULL);
+
+ return ret;
+}
+
+static struct blkz_zone *blkz_init_zone(enum pstore_type_id type,
+ unsigned long *off, size_t size)
+{
+ struct blkz_info *info = blkz_cxt.bzinfo;
+ struct blkz_zone *zone;
+ const char *name = pstore_type_to_name(type);
+
+ if (!size)
+ return NULL;
+
+ if (*off + size > info->part_size) {
+ pr_err("no room for %s (0x%zx@0x%lx over 0x%lx)\n",
+ name, size, *off, info->part_size);
+ return ERR_PTR(-ENOMEM);
+ }
+
+ zone = kzalloc(sizeof(struct blkz_zone), GFP_KERNEL);
+ if (!zone)
+ return ERR_PTR(-ENOMEM);
+
+ /**
+ * NOTE: allocate buffer for blk zones for two reasons:
+ * 1. It can temporarily hold the data before
+ * blkz_default_general_read/write are useable.
+ * 2. It makes pstore usable even if no persistent storage. Most
+ * events of pstore except panic are suitable!!
+ */
+ 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 blkz_buffer);
+ zone->buffer->sig = type ^ BLK_SIG;
+ atomic_set(&zone->dirty, 0);
+ atomic_set(&zone->buffer->datalen, 0);
+
+ *off += size;
+
+ pr_debug("blkzone %s: off 0x%lx, %zu header, %zu data\n", zone->name,
+ zone->off, sizeof(*zone->buffer), zone->buffer_size);
+ return zone;
+}
+
+static struct blkz_zone **blkz_init_zones(enum pstore_type_id type,
+ unsigned long *off, size_t total_size, ssize_t record_size,
+ unsigned int *cnt)
+{
+ struct blkz_info *info = blkz_cxt.bzinfo;
+ struct blkz_zone **zones, *zone;
+ const char *name = pstore_type_to_name(type);
+ int c, i;
+
+ if (!total_size || !record_size)
+ return NULL;
+
+ if (*off + total_size > info->part_size) {
+ pr_err("no room for zones %s (0x%zx@0x%lx over 0x%lx)\n",
+ name, total_size, *off, info->part_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 = blkz_init_zone(type, off, record_size);
+ if (!zone || IS_ERR(zone)) {
+ pr_err("initialize zones %s failed\n", name);
+ while (--i >= 0)
+ kfree(zones[i]);
+ kfree(zones);
+ return (void *)zone;
+ }
+ zones[i] = zone;
+ }
+
+ *cnt = c;
+ return zones;
+}
+
+static void blkz_free_zone(struct blkz_zone **blkzone)
+{
+ struct blkz_zone *zone = *blkzone;
+
+ if (!zone)
+ return;
+
+ kfree(zone->buffer);
+ kfree(zone);
+ *blkzone = NULL;
+}
+
+static void blkz_free_zones(struct blkz_zone ***blkzones, unsigned int *cnt)
+{
+ struct blkz_zone **zones = *blkzones;
+
+ while (*cnt > 0) {
+ blkz_free_zone(&zones[*cnt]);
+ (*cnt)--;
+ }
+ kfree(zones);
+ *blkzones = NULL;
+}
+
+static int blkz_cut_zones(struct blkz_context *cxt)
+{
+ struct blkz_info *info = cxt->bzinfo;
+ unsigned long off = 0;
+ int err;
+ size_t size;
+
+ size = info->part_size;
+ cxt->dbzs = blkz_init_zones(PSTORE_TYPE_DMESG, &off, size,
+ info->dmesg_size, &cxt->dmesg_max_cnt);
+ if (IS_ERR(cxt->dbzs)) {
+ err = PTR_ERR(cxt->dbzs);
+ goto fail_out;
+ }
+
+ return 0;
+fail_out:
+ return err;
+}
+
+int blkz_register(struct blkz_info *info)
+{
+ int err = -EINVAL;
+ struct blkz_context *cxt = &blkz_cxt;
+ struct module *owner = info->owner;
+
+ if (!info->part_size || !info->dmesg_size) {
+ pr_warn("The memory size and the dmesg size must be non-zero\n");
+ return -EINVAL;
+ }
+
+ if (info->part_size < 4096) {
+ pr_err("partition size must be over 4096 bytes\n");
+ return -EINVAL;
+ }
+
+#define check_size(name, size) { \
+ if (info->name & (size - 1)) { \
+ pr_err(#name " must be a multiple of %d\n", \
+ (size)); \
+ return -EINVAL; \
+ } \
+ }
+
+ check_size(part_size, 4096);
+ check_size(dmesg_size, SECTOR_SIZE);
+
+#undef check_size
+
+ if (!info->read)
+ info->read = blkz_default_general_read;
+ if (!info->write)
+ info->write = blkz_default_general_write;
+
+ if (owner && !try_module_get(owner))
+ return -EINVAL;
+
+ spin_lock(&cxt->bzinfo_lock);
+ if (cxt->bzinfo) {
+ pr_warn("blk '%s' already loaded: ignoring '%s'\n",
+ cxt->bzinfo->name, info->name);
+ spin_unlock(&cxt->bzinfo_lock);
+ return -EBUSY;
+ }
+ cxt->bzinfo = info;
+ spin_unlock(&cxt->bzinfo_lock);
+
+ if (blkz_cut_zones(cxt)) {
+ pr_err("cut zones fialed\n");
+ goto fail_out;
+ }
+
+ cxt->pstore.bufsize = cxt->dbzs[0]->buffer_size -
+ sizeof(struct blkz_dmesg_header);
+ cxt->pstore.buf = kzalloc(cxt->pstore.bufsize, GFP_KERNEL);
+ if (!cxt->pstore.buf) {
+ pr_err("cannot allocate pstore crash dump buffer\n");
+ err = -ENOMEM;
+ goto fail_out;
+ }
+ cxt->pstore.data = cxt;
+ cxt->pstore.flags = PSTORE_FLAGS_DMESG;
+
+ pr_info("Registered %s as blkzone backend for %s%s\n", info->name,
+ cxt->dbzs && cxt->bzinfo->dump_oops ? "Oops " : "",
+ cxt->dbzs && cxt->bzinfo->panic_write ? "Panic " : "");
+
+ err = pstore_register(&cxt->pstore);
+ if (err) {
+ pr_err("registering with pstore failed\n");
+ goto free_pstore_buf;
+ }
+
+ module_put(owner);
+ return 0;
+
+free_pstore_buf:
+ kfree(cxt->pstore.buf);
+fail_out:
+ spin_lock(&blkz_cxt.bzinfo_lock);
+ blkz_cxt.bzinfo = NULL;
+ spin_unlock(&blkz_cxt.bzinfo_lock);
+ return err;
+}
+EXPORT_SYMBOL_GPL(blkz_register);
+
+void blkz_unregister(struct blkz_info *info)
+{
+ struct blkz_context *cxt = &blkz_cxt;
+
+ pstore_unregister(&cxt->pstore);
+ kfree(cxt->pstore.buf);
+ cxt->pstore.bufsize = 0;
+
+ spin_lock(&cxt->bzinfo_lock);
+ blkz_cxt.bzinfo = NULL;
+ spin_unlock(&cxt->bzinfo_lock);
+
+ blkz_free_zones(&cxt->dbzs, &cxt->dmesg_max_cnt);
+
+}
+EXPORT_SYMBOL_GPL(blkz_unregister);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("liaoweixiong <liaoweixiong@allwinnertech.com>");
+MODULE_DESCRIPTION("Block device Oops/Panic logger");
diff --git a/include/linux/pstore_blk.h b/include/linux/pstore_blk.h
new file mode 100644
index 0000000..27b282d
--- /dev/null
+++ b/include/linux/pstore_blk.h
@@ -0,0 +1,61 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef __PSTORE_BLK_H_
+#define __PSTORE_BLK_H_
+
+#include <linux/types.h>
+#include <linux/blkdev.h>
+
+#ifndef SECTOR_SIZE
+#define SECTOR_SIZE 512
+#endif
+
+/**
+ * struct blkz_info - backend blkzone driver structure
+ *
+ * @owner:
+ * module which is responsible for this backend driver
+ * @name:
+ * name of the backend driver
+ * @part_path:
+ * path of a storage partition. It's ok to keep it as NULL
+ * if you passing @read and @write in blkz_info. @part_path
+ * is needed by blkz_default_general_read/write. If both of
+ * @part_path, @read and @write are NULL, it will temporarity
+ * hold the data in buffer allocated by 'kmalloc'.
+ * @part_size:
+ * total size of a storage partition in bytes. The partition
+ * will be used to save data of pstore.
+ * @dmesg_size:
+ * the size of each zones for dmesg (oops & panic).
+ * @dump_oops:
+ * dump oops and panic log or only panic.
+ * @read:
+ * the general (not panic) read operation. If NULL, pstore/blk
+ * replaced as blkz_default_general_read. See also @part_path
+ * @write:
+ * the general (not panic) write operation. If NULL, pstore/blk
+ * replaced as blkz_default_general_write. See also @part_path
+ * @panic_read:
+ * the read operation only used for panic.
+ * @panic_write:
+ * the write operation only used for panic.
+ */
+struct blkz_info {
+ struct module *owner;
+ const char *name;
+
+ const char *part_path;
+ unsigned long part_size;
+ unsigned long dmesg_size;
+ int dump_oops;
+ ssize_t (*read)(char *buf, size_t bytes, loff_t pos);
+ ssize_t (*write)(const char *buf, size_t bytes, loff_t pos);
+ ssize_t (*panic_read)(char *buf, size_t bytes, loff_t pos);
+ ssize_t (*panic_write)(const char *buf, size_t bytes, loff_t pos);
+};
+
+extern int blkz_register(struct blkz_info *info);
+extern void blkz_unregister(struct blkz_info *info);
+
+#endif
--
1.9.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* [RFC v8 2/5] dt-bindings: pstore-block: new support for blkoops
2019-02-13 14:07 [RFC v8 0/5] pstore/block: new support logger for block devices liaoweixiong
2019-02-13 14:07 ` [RFC v8 1/5] pstore/blk: " liaoweixiong
@ 2019-02-13 14:07 ` liaoweixiong
2019-02-13 14:07 ` [RFC v8 3/5] pstore/blk: add blkoops for pstore_blk liaoweixiong
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: liaoweixiong @ 2019-02-13 14:07 UTC (permalink / raw)
To: Kees Cook, Anton Vorontsov, Colin Cross, Tony Luck,
Jonathan Corbet, Rob Herring, Mark Rutland, liaoweixiong,
Mauro Carvalho Chehab, David S. Miller, Greg Kroah-Hartman,
Nicolas Ferre, Arnd Bergmann
Cc: linux-doc, linux-kernel, devicetree
Create DT binding document for blkoops.
Signed-off-by: liaoweixiong <liaoweixiong@allwinnertech.com>
---
.../devicetree/bindings/pstore/blkoops.txt | 29 ++++++++++++++++++++++
MAINTAINERS | 1 +
2 files changed, 30 insertions(+)
create mode 100644 Documentation/devicetree/bindings/pstore/blkoops.txt
diff --git a/Documentation/devicetree/bindings/pstore/blkoops.txt b/Documentation/devicetree/bindings/pstore/blkoops.txt
new file mode 100644
index 0000000..8f3d85f
--- /dev/null
+++ b/Documentation/devicetree/bindings/pstore/blkoops.txt
@@ -0,0 +1,29 @@
+Blkoops oops logger
+===================
+
+Blkoops provides a block partition for oops, excluding panics now, so they can
+be recovered after a reboot.
+
+Any space of block partition will be used for a circular buffer of oops records.
+These records have a configurable size, with a size of 0 indicating that they
+should be disabled.
+
+"partition-size" and at least one of "dmesg-size" or "pmsg-size" must be set
+non-zero, but are otherwise optional as listed below.
+
+Required properties:
+
+- compatible: must be "blkoops".
+
+- partition-size: size in kbytes, must be a multiple of 4.
+
+Optional properties:
+
+- partition-path: strings must begin with "/dev", tell blkoops which partition
+ it can used. If it is not set, blkoops will drop all data when reboot.
+
+- dmesg-size: maximum size in kbytes of each dump done on oops, which must be a
+ multiple of 4.
+
+- pmsg-size: maximum size in kbytes for userspace messages, which must be a
+ multiple of 4.
diff --git a/MAINTAINERS b/MAINTAINERS
index 51029a4..f49dd37 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -12318,6 +12318,7 @@ F: drivers/firmware/efi/efi-pstore.c
F: drivers/acpi/apei/erst.c
F: Documentation/admin-guide/ramoops.rst
F: Documentation/devicetree/bindings/reserved-memory/ramoops.txt
+F: Documentation/devicetree/bindings/pstore-block/
K: \b(pstore|ramoops)
PTP HARDWARE CLOCK SUPPORT
--
1.9.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* [RFC v8 3/5] pstore/blk: add blkoops for pstore_blk
2019-02-13 14:07 [RFC v8 0/5] pstore/block: new support logger for block devices liaoweixiong
2019-02-13 14:07 ` [RFC v8 1/5] pstore/blk: " liaoweixiong
2019-02-13 14:07 ` [RFC v8 2/5] dt-bindings: pstore-block: new support for blkoops liaoweixiong
@ 2019-02-13 14:07 ` liaoweixiong
2019-02-13 14:07 ` [RFC v8 4/5] pstore/blk: support pmsg for pstore block liaoweixiong
2019-02-13 14:07 ` [RFC v8 5/5] Documentation: pstore/blk: create document for pstore_blk liaoweixiong
4 siblings, 0 replies; 6+ messages in thread
From: liaoweixiong @ 2019-02-13 14:07 UTC (permalink / raw)
To: Kees Cook, Anton Vorontsov, Colin Cross, Tony Luck,
Jonathan Corbet, Rob Herring, Mark Rutland, liaoweixiong,
Mauro Carvalho Chehab, David S. Miller, Greg Kroah-Hartman,
Nicolas Ferre, Arnd Bergmann
Cc: linux-doc, linux-kernel, devicetree
blkoops is a sample for pstore/blk. It can only record oops, excluding
panics as no read/write apis for panic registered. It support settings
on Kconfg/device tree/module parameters. It can record oops log even
power failure if "PSTORE_BLKOOPS_PART_PATH" on Kconfig or
"partition-path" on dts or "part_path" on module parameter is valid.
Otherwise, it can only record data to ram buffer, which will be dropped
when reboot.
Signed-off-by: liaoweixiong <liaoweixiong@allwinnertech.com>
---
MAINTAINERS | 2 +-
fs/pstore/Kconfig | 117 +++++++++++++++++++++++++
fs/pstore/Makefile | 2 +
fs/pstore/blkoops.c | 239 ++++++++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 359 insertions(+), 1 deletion(-)
create mode 100644 fs/pstore/blkoops.c
diff --git a/MAINTAINERS b/MAINTAINERS
index f49dd37..44647a8 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -12319,7 +12319,7 @@ F: drivers/acpi/apei/erst.c
F: Documentation/admin-guide/ramoops.rst
F: Documentation/devicetree/bindings/reserved-memory/ramoops.txt
F: Documentation/devicetree/bindings/pstore-block/
-K: \b(pstore|ramoops)
+K: \b(pstore|ramoops|blkoops)
PTP HARDWARE CLOCK SUPPORT
M: Richard Cochran <richardcochran@gmail.com>
diff --git a/fs/pstore/Kconfig b/fs/pstore/Kconfig
index a881c53..f0a1a49 100644
--- a/fs/pstore/Kconfig
+++ b/fs/pstore/Kconfig
@@ -159,3 +159,120 @@ config PSTORE_BLK
help
This enables panic and oops message to be logged to a block dev
where it can be read back at some later point.
+
+config PSTORE_BLKOOPS
+ tristate "pstore block with oops logger"
+ depends on PSTORE_BLK
+ help
+ This is a sample for pstore block with oops logger.
+
+ It CANNOT record panic log as no read/write apis for panic registered.
+
+ It CAN record oops log even power failure if
+ "PSTORE_BLKOOPS_PART_PATH" on Kconfig or "partition-path" on dts or
+ "part_path" on module parameter is valid.
+
+ Otherwise, it can only record data to ram buffer, which will be
+ dropped when reboot.
+
+ NOTE that, there are three ways to set parameters of blkoops and
+ prioritize according to configuration flexibility. That is
+ Kconfig < device tree < module parameters. It means that the value can
+ be overwritten by higher priority settings.
+ 1. Kconfig
+ It just sets a default value.
+ 2. device tree
+ It is set on device tree, which will overwrites value from Kconfig,
+ but can also be overwritten by module parameters.
+ 3. module parameters
+ It is the first priority. Take care of that blkoops will take lower
+ priority settings if higher priority one do not set.
+
+config PSTORE_BLKOOPS_DMESG_SIZE
+ int "dmesg_size in kbytes for blkoops"
+ depends on PSTORE_BLKOOPS
+ default 64
+ help
+ This just sets size of dmesg (dmesg_size) for pstore/blk. The value
+ must be a multiple of 4096.
+
+ NOTE that, there are three ways to set parameters of blkoops and
+ prioritize according to configuration flexibility. That is
+ Kconfig < device tree < module parameters. It means that the value can
+ be overwritten by higher priority settings.
+ 1. Kconfig
+ It just sets a default value.
+ 2. device tree
+ It is set on device tree, which will overwrites value from Kconfig,
+ but can also be overwritten by module parameters.
+ 3. module parameters
+ It is the first priority. Take care of that blkoops will take lower
+ priority settings if higher priority one do not set.
+
+config PSTORE_BLKOOPS_PMSG_SIZE
+ int "pmsg_size in kbytes for blkoops"
+ depends on PSTORE_BLKOOPS
+ default 64
+ help
+ This just sets size of pmsg (pmsg_size) for pstore/blk. The value must
+ be a multiple of 4096. Pmsg work only if "part_path" is set.
+
+ NOTE that, there are three ways to set parameters of blkoops and
+ prioritize according to configuration flexibility. That is
+ Kconfig < device tree < module parameters. It means that the value can
+ be overwritten by higher priority settings.
+ 1. Kconfig
+ It just sets a default value.
+ 2. device tree
+ It is set on device tree, which will overwrites value from Kconfig,
+ but can also be overwritten by module parameters.
+ 3. module parameters
+ It is the first priority. Take care of that blkoops will take lower
+ priority settings if higher priority one do not set.
+
+config PSTORE_BLKOOPS_PART_SIZE
+ int "part_size in kbytes for blkoops"
+ depends on PSTORE_BLKOOPS
+ default 1024
+ help
+ This just sets partition size (part_size) for pstore/blk. Pstore/blk
+ will allocate part_size memory to temporarily hold the data. It's the
+ size of partition on part_path. The value must be a multiple of 4096.
+
+ NOTE that, there are three ways to set parameters of blkoops and
+ prioritize according to configuration flexibility. That is
+ Kconfig < device tree < module parameters. It means that the value can
+ be overwritten by higher priority settings.
+ 1. Kconfig
+ It just sets a default value.
+ 2. device tree
+ It is set on device tree, which will overwrites value from Kconfig,
+ but can also be overwritten by module parameters.
+ 3. module parameters
+ It is the first priority. Take care of that blkoops will take lower
+ priority settings if higher priority one do not set.
+
+config PSTORE_BLKOOPS_PART_PATH
+ string "part_path for blkoops"
+ depends on PSTORE_BLKOOPS
+ default ""
+ help
+ This just sets partition path (part_path) for pstore/blk. Pstore/blk
+ will record data to this block partition to avoid losing data due to
+ power failure. So, If it is not set, pstore/blk will drop all data
+ when reboot.
+
+ The strings must begin with "/dev/".
+
+ NOTE that, there are three ways to set parameters of blkoops and
+ prioritize according to configuration flexibility. That is
+ Kconfig < device tree < module parameters. It means that the value can
+ be overwritten by higher priority settings.
+ 1. Kconfig
+ It just sets a default value.
+ 2. device tree
+ It is set on device tree, which will overwrites value from Kconfig,
+ but can also be overwritten by module parameters.
+ 3. module parameters
+ It is the first priority. Take care of that blkoops will take lower
+ priority settings if higher priority one do not set.
diff --git a/fs/pstore/Makefile b/fs/pstore/Makefile
index 0ee2fc8..24b3d48 100644
--- a/fs/pstore/Makefile
+++ b/fs/pstore/Makefile
@@ -15,3 +15,5 @@ obj-$(CONFIG_PSTORE_RAM) += ramoops.o
obj-$(CONFIG_PSTORE_BLK) += pstore_blk.o
pstore_blk-y += blkzone.o
+
+obj-$(CONFIG_PSTORE_BLKOOPS) += blkoops.o
diff --git a/fs/pstore/blkoops.c b/fs/pstore/blkoops.c
new file mode 100644
index 0000000..fd926a5
--- /dev/null
+++ b/fs/pstore/blkoops.c
@@ -0,0 +1,239 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *
+ * blkoops.c: Block device Oops logger
+ *
+ * Copyright (C) 2019 liaoweixiong <liaoweixiong@gallwinnertech.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ */
+#define MODNAME "blkoops"
+#define pr_fmt(fmt) MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/platform_device.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/pstore_blk.h>
+
+static long dmesg_size = -1;
+module_param(dmesg_size, long, 0400);
+MODULE_PARM_DESC(dmesg_size, "demsg size in kbytes");
+
+static long part_size = -1;
+module_param(part_size, long, 0400);
+MODULE_PARM_DESC(part_size, "partition size in kbytes");
+
+#define PART_PATH_INVALID "INVALID"
+static char part_path[80] = {PART_PATH_INVALID};
+module_param_string(part_path, part_path, 80, 0400);
+MODULE_PARM_DESC(part_path, "path of partition in /dev for general read/write");
+
+struct blkz_info blkz_info = {
+ .owner = THIS_MODULE,
+ .name = "blkoops",
+ .dump_oops = true,
+};
+
+struct blkoops_info {
+ unsigned long dmesg_size;
+ unsigned long part_size;
+ const char *part_path;
+};
+struct blkoops_info blkoops_info = {
+ .dmesg_size = CONFIG_PSTORE_BLKOOPS_DMESG_SIZE * 1024,
+ .part_size = CONFIG_PSTORE_BLKOOPS_PART_SIZE * 1024,
+ .part_path = CONFIG_PSTORE_BLKOOPS_PART_PATH,
+};
+
+static struct platform_device *dummy;
+
+static int blkoops_parse_dt_size(struct device_node *np,
+ const char *propname, u32 *value)
+{
+ u32 val32 = 0;
+ int ret;
+
+ ret = of_property_read_u32(np, propname, &val32);
+ if (ret < 0) {
+ if (ret != -EINVAL)
+ pr_err("failed to parse property %s: %d\n",
+ propname, ret);
+ return ret;
+ }
+
+ if (val32 * 1024 > INT_MAX) {
+ pr_err("%s %u > INT_MAX\n", propname, val32);
+ return -EOVERFLOW;
+ }
+
+ *value = val32 * 1024;
+ return 0;
+}
+
+static int __init blkoops_parse_dt(struct blkoops_info *info,
+ struct device_node *np)
+{
+ int ret;
+ u32 value;
+
+ pr_info("using device tree\n");
+
+ ret = of_property_read_string(np, "partition-path",
+ &info->part_path);
+ if (ret < 0 && ret != -EINVAL) {
+ pr_err("failed to parse partition path : %d\n", ret);
+ return ret;
+ }
+
+#define parse_size(name, field) { \
+ ret = blkoops_parse_dt_size(np, name, &value); \
+ if (ret < 0 && ret != -EINVAL) \
+ return ret; \
+ else if (ret == 0) \
+ field = value; \
+ }
+
+ parse_size("partition-size", info->part_size);
+ parse_size("dmesg-size", info->dmesg_size);
+
+#undef parse_size
+ return 0;
+}
+
+static int blkoops_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct device_node *of_node = dev_of_node(dev);
+ struct blkoops_info *info = dev->platform_data;
+
+ if (of_node && !info) {
+ int err;
+
+ info = &blkoops_info;
+ err = blkoops_parse_dt(info, of_node);
+ if (err)
+ return err;
+ }
+
+ if (!strcmp(info->part_path, PART_PATH_INVALID) ||
+ strlen(info->part_path) == 0) {
+ pr_info("no path for block partition, use ram buffer only\n");
+ } else if (strncmp(info->part_path, "/dev/", 5) != 0) {
+ pr_err("invalid partition path %s, use ram buffer only\n",
+ info->part_path);
+ } else {
+ pr_debug("path for block partition: %s\n", info->part_path);
+ blkz_info.part_path = info->part_path;
+ }
+
+#define check_size(name, size) { \
+ if (info->name & (size - 1)) { \
+ pr_err(#name " must be a multiple of %d\n", \
+ (size)); \
+ return -EINVAL; \
+ } \
+ blkz_info.name = info->name; \
+ }
+
+ check_size(part_size, 4096);
+ check_size(dmesg_size, 4096);
+
+#undef check_size
+
+ /*
+ * Update the module parameter variables as well so they are visible
+ * through /sys/module/blkoops/parameters/
+ */
+ dmesg_size = blkz_info.dmesg_size;
+ part_size = blkz_info.part_size;
+ if (blkz_info.part_path)
+ strncpy(part_path, blkz_info.part_path, 80 - 1);
+ else
+ part_path[0] = '\0';
+ return blkz_register(&blkz_info);
+}
+
+static int blkoops_remove(struct platform_device *pdev)
+{
+ blkz_unregister(&blkz_info);
+ return 0;
+}
+
+static const struct of_device_id dt_match[] = {
+ { .compatible = MODNAME},
+ {}
+};
+
+static struct platform_driver blkoops_driver = {
+ .probe = blkoops_probe,
+ .remove = blkoops_remove,
+ .driver = {
+ .name = MODNAME,
+ .of_match_table = dt_match,
+ },
+};
+
+void blkoops_register_dummy(void)
+{
+ struct blkoops_info *info = &blkoops_info;
+ /*
+ * Prepare a dummy platform data structure to carry the module
+ * parameters. If mem_size isn't set, then there are no module
+ * parameters, and we can skip this.
+ */
+ if (part_size < 0)
+ return;
+
+ pr_info("using module parameters\n");
+
+ info->part_size = (unsigned long)part_size * 1024;
+ if (strcmp(part_path, PART_PATH_INVALID))
+ info->part_path = (const char *)part_path;
+ if (dmesg_size >= 0)
+ info->dmesg_size = (unsigned long)dmesg_size * 1024;
+
+ dummy = platform_device_register_data(NULL, MODNAME, -1, info,
+ sizeof(*info));
+ if (IS_ERR(dummy)) {
+ pr_err("could not create platform device: %ld\n",
+ PTR_ERR(dummy));
+ dummy = NULL;
+ }
+}
+
+static int __init blkoops_init(void)
+{
+ int ret;
+
+ blkoops_register_dummy();
+ ret = platform_driver_register(&blkoops_driver);
+ if (ret != 0) {
+ platform_device_unregister(dummy);
+ dummy = NULL;
+ }
+ return ret;
+}
+module_init(blkoops_init);
+
+static void __exit blkoops_exit(void)
+{
+ platform_driver_unregister(&blkoops_driver);
+ platform_device_unregister(dummy);
+ dummy = NULL;
+}
+module_exit(blkoops_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("liaoweixiong <liaoweixiong@allwinnertech.com>");
+MODULE_DESCRIPTION("Sample for Pstore BLK with Oops logger");
--
1.9.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* [RFC v8 4/5] pstore/blk: support pmsg for pstore block
2019-02-13 14:07 [RFC v8 0/5] pstore/block: new support logger for block devices liaoweixiong
` (2 preceding siblings ...)
2019-02-13 14:07 ` [RFC v8 3/5] pstore/blk: add blkoops for pstore_blk liaoweixiong
@ 2019-02-13 14:07 ` liaoweixiong
2019-02-13 14:07 ` [RFC v8 5/5] Documentation: pstore/blk: create document for pstore_blk liaoweixiong
4 siblings, 0 replies; 6+ messages in thread
From: liaoweixiong @ 2019-02-13 14:07 UTC (permalink / raw)
To: Kees Cook, Anton Vorontsov, Colin Cross, Tony Luck,
Jonathan Corbet, Rob Herring, Mark Rutland, liaoweixiong,
Mauro Carvalho Chehab, David S. Miller, Greg Kroah-Hartman,
Nicolas Ferre, Arnd Bergmann
Cc: linux-doc, linux-kernel, devicetree
To enable pmsg, just set pmsg_size when block device register blkzone.
Signed-off-by: liaoweixiong <liaoweixiong@allwinnertech.com>
---
fs/pstore/blkoops.c | 11 ++
fs/pstore/blkzone.c | 254 +++++++++++++++++++++++++++++++++++++++++----
include/linux/pstore_blk.h | 1 +
3 files changed, 244 insertions(+), 22 deletions(-)
diff --git a/fs/pstore/blkoops.c b/fs/pstore/blkoops.c
index fd926a5..b4b658e 100644
--- a/fs/pstore/blkoops.c
+++ b/fs/pstore/blkoops.c
@@ -30,6 +30,10 @@
module_param(dmesg_size, long, 0400);
MODULE_PARM_DESC(dmesg_size, "demsg size in kbytes");
+static long pmsg_size = -1;
+module_param(pmsg_size, long, 0400);
+MODULE_PARM_DESC(pmsg_size, "pmsg size in kbytes");
+
static long part_size = -1;
module_param(part_size, long, 0400);
MODULE_PARM_DESC(part_size, "partition size in kbytes");
@@ -47,11 +51,13 @@ struct blkz_info blkz_info = {
struct blkoops_info {
unsigned long dmesg_size;
+ unsigned long pmsg_size;
unsigned long part_size;
const char *part_path;
};
struct blkoops_info blkoops_info = {
.dmesg_size = CONFIG_PSTORE_BLKOOPS_DMESG_SIZE * 1024,
+ .pmsg_size = CONFIG_PSTORE_BLKOOPS_PMSG_SIZE * 1024,
.part_size = CONFIG_PSTORE_BLKOOPS_PART_SIZE * 1024,
.part_path = CONFIG_PSTORE_BLKOOPS_PART_PATH,
};
@@ -106,6 +112,7 @@ static int __init blkoops_parse_dt(struct blkoops_info *info,
parse_size("partition-size", info->part_size);
parse_size("dmesg-size", info->dmesg_size);
+ parse_size("pmsg-size", info->pmsg_size);
#undef parse_size
return 0;
@@ -148,6 +155,7 @@ static int blkoops_probe(struct platform_device *pdev)
check_size(part_size, 4096);
check_size(dmesg_size, 4096);
+ check_size(pmsg_size, 4096);
#undef check_size
@@ -156,6 +164,7 @@ static int blkoops_probe(struct platform_device *pdev)
* through /sys/module/blkoops/parameters/
*/
dmesg_size = blkz_info.dmesg_size;
+ pmsg_size = blkz_info.pmsg_size;
part_size = blkz_info.part_size;
if (blkz_info.part_path)
strncpy(part_path, blkz_info.part_path, 80 - 1);
@@ -202,6 +211,8 @@ void blkoops_register_dummy(void)
info->part_path = (const char *)part_path;
if (dmesg_size >= 0)
info->dmesg_size = (unsigned long)dmesg_size * 1024;
+ if (pmsg_size >= 0)
+ info->pmsg_size = (unsigned long)pmsg_size * 1024;
dummy = platform_device_register_data(NULL, MODNAME, -1, info,
sizeof(*info));
diff --git a/fs/pstore/blkzone.c b/fs/pstore/blkzone.c
index aca8c2a..0736472 100644
--- a/fs/pstore/blkzone.c
+++ b/fs/pstore/blkzone.c
@@ -34,12 +34,14 @@
*
* @sig: signature to indicate header (BLK_SIG xor BLKZONE-type value)
* @datalen: length of data in @data
+ * @start: offset into @data where the beginning of the stored bytes begin
* @data: zone data.
*/
struct blkz_buffer {
#define BLK_SIG (0x43474244) /* DBGC */
uint32_t sig;
atomic_t datalen;
+ atomic_t start;
uint8_t data[];
};
@@ -72,6 +74,9 @@ struct blkz_dmesg_header {
* frontent name for this zone
* @buffer:
* pointer to data buffer managed by this zone
+ * @oldbuf:
+ * pointer to old data buffer. It is used for single zone such as pmsg,
+ * saving the old buffer.
* @buffer_size:
* bytes in @buffer->data
* @should_recover:
@@ -85,6 +90,7 @@ struct blkz_zone {
enum pstore_type_id type;
struct blkz_buffer *buffer;
+ struct blkz_buffer *oldbuf;
size_t buffer_size;
bool should_recover;
atomic_t dirty;
@@ -92,8 +98,10 @@ struct blkz_zone {
struct blkz_context {
struct blkz_zone **dbzs; /* dmesg block zones */
+ struct blkz_zone *pbz; /* Pmsg block zone */
unsigned int dmesg_max_cnt;
unsigned int dmesg_read_cnt;
+ unsigned int pmsg_read_cnt;
unsigned int dmesg_write_cnt;
/**
* the counter should be recovered when do recovery
@@ -127,6 +135,11 @@ static inline int buffer_datalen(struct blkz_zone *zone)
return atomic_read(&zone->buffer->datalen);
}
+static inline int buffer_start(struct blkz_zone *zone)
+{
+ return atomic_read(&zone->buffer->start);
+}
+
static inline bool is_on_panic(void)
{
struct blkz_context *cxt = &blkz_cxt;
@@ -401,6 +414,72 @@ static int blkz_recover_dmesg(struct blkz_context *cxt)
return ret;
}
+static int blkz_recover_pmsg(struct blkz_context *cxt)
+{
+ struct blkz_info *info = cxt->bzinfo;
+ struct blkz_buffer *oldbuf;
+ struct blkz_zone *zone = NULL;
+ ssize_t (*readop)(char *buf, size_t bytes, loff_t pos);
+ int ret = 0;
+ ssize_t rcnt, len;
+
+ zone = cxt->pbz;
+ if (!zone || zone->oldbuf)
+ return 0;
+
+ if (is_on_panic())
+ goto out;
+
+ readop = info->read;
+ if (unlikely(!readop))
+ return -EINVAL;
+
+ len = zone->buffer_size + sizeof(*oldbuf);
+ oldbuf = kzalloc(len, GFP_KERNEL);
+ if (!oldbuf)
+ return -ENOMEM;
+
+ rcnt = readop((char *)oldbuf, len, zone->off);
+ if (rcnt != len) {
+ pr_debug("recover pmsg failed\n");
+ ret = (int)rcnt < 0 ? (int)rcnt : -EIO;
+ goto free_oldbuf;
+ }
+
+ if (oldbuf->sig != zone->buffer->sig) {
+ pr_debug("no valid data in zone %s\n", zone->name);
+ goto free_oldbuf;
+ }
+
+ if (zone->buffer_size < atomic_read(&oldbuf->datalen) ||
+ zone->buffer_size < atomic_read(&oldbuf->start)) {
+ pr_info("found overtop zone: %s: off %lu, size %zu\n",
+ zone->name, zone->off, zone->buffer_size);
+ goto free_oldbuf;
+ }
+
+ if (!atomic_read(&oldbuf->datalen)) {
+ pr_debug("found erased zone: %s: id 0, off %lu, size %zu, datalen %d\n",
+ zone->name, zone->off, zone->buffer_size,
+ atomic_read(&oldbuf->datalen));
+ kfree(oldbuf);
+ goto out;
+ }
+
+ pr_debug("found nice zone: %s: id 0, off %lu, size %zu, datalen %d\n",
+ zone->name, zone->off, zone->buffer_size,
+ atomic_read(&oldbuf->datalen));
+ zone->oldbuf = oldbuf;
+out:
+ if (atomic_read(&zone->dirty))
+ blkz_zone_write(zone, FLUSH_ALL, NULL, buffer_datalen(zone), 0);
+ return 0;
+
+free_oldbuf:
+ kfree(oldbuf);
+ return ret;
+}
+
static inline int blkz_recovery(struct blkz_context *cxt)
{
int ret = -EBUSY;
@@ -415,6 +494,10 @@ static inline int blkz_recovery(struct blkz_context *cxt)
if (ret)
goto recover_fail;
+ ret = blkz_recover_pmsg(cxt);
+ if (ret)
+ goto recover_fail;
+
atomic_set(&cxt->recovery, 1);
pr_debug("recover end!\n");
return 0;
@@ -432,11 +515,18 @@ static int blkz_pstore_open(struct pstore_info *psi)
return 0;
}
+static inline bool blkz_old_ok(struct blkz_zone *zone)
+{
+ if (zone && zone->oldbuf && atomic_read(&zone->oldbuf->datalen))
+ return true;
+ return false;
+}
+
static inline bool blkz_ok(struct blkz_zone *zone)
{
- if (!zone || !zone->buffer || !buffer_datalen(zone))
- return false;
- return true;
+ if (zone && zone->buffer && buffer_datalen(zone))
+ return true;
+ return false;
}
static int blkz_pstore_erase(struct pstore_record *record)
@@ -444,13 +534,29 @@ static int blkz_pstore_erase(struct pstore_record *record)
struct blkz_context *cxt = record->psi->data;
struct blkz_zone *zone = NULL;
- if (record->type == PSTORE_TYPE_DMESG)
+ if (record->type == PSTORE_TYPE_DMESG) {
zone = cxt->dbzs[record->id];
- if (!blkz_ok(zone))
- return 0;
+ if (unlikely(!blkz_ok(zone)))
+ return 0;
- atomic_set(&zone->buffer->datalen, 0);
- return blkz_zone_write(zone, FLUSH_META, NULL, 0, 0);
+ atomic_set(&zone->buffer->datalen, 0);
+ return blkz_zone_write(zone, FLUSH_META, NULL, 0, 0);
+ } else if (record->type == PSTORE_TYPE_PMSG) {
+ zone = cxt->pbz;
+ if (unlikely(!blkz_old_ok(zone)))
+ return 0;
+
+ kfree(zone->oldbuf);
+ zone->oldbuf = NULL;
+ /**
+ * if there is new data in zone buffer, there is no need to
+ * flush 0 (erase) to block device
+ */
+ if (buffer_datalen(zone))
+ return 0;
+ return blkz_zone_write(zone, FLUSH_META, NULL, 0, 0);
+ }
+ return -EINVAL;
}
static void blkz_write_kmsg_hdr(struct blkz_zone *zone,
@@ -468,8 +574,10 @@ static void blkz_write_kmsg_hdr(struct blkz_zone *zone,
hdr->reason = record->reason;
if (hdr->reason == KMSG_DUMP_OOPS)
hdr->counter = ++cxt->oops_counter;
- else
+ else if (hdr->reason == KMSG_DUMP_PANIC)
hdr->counter = ++cxt->panic_counter;
+ else
+ hdr->counter = 0;
}
static int notrace blkz_dmesg_write(struct blkz_context *cxt,
@@ -519,6 +627,55 @@ static int notrace blkz_dmesg_write(struct blkz_context *cxt,
return 0;
}
+static int notrace blkz_pmsg_write(struct blkz_context *cxt,
+ struct pstore_record *record)
+{
+ struct blkz_zone *zone;
+ size_t start, rem;
+ int cnt = record->size;
+ bool is_full_data = false;
+ char *buf = record->buf;
+
+ zone = cxt->pbz;
+ if (!zone)
+ return -ENOSPC;
+
+ if (atomic_read(&zone->buffer->datalen) >= zone->buffer_size)
+ is_full_data = true;
+
+ 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)) {
+ blkz_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);
+ blkz_zone_write(zone, FLUSH_PART, buf, cnt, start);
+
+ /**
+ * blkz_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);
+ blkz_zone_write(zone, FLUSH_META, NULL, 0, 0);
+ }
+ return 0;
+}
+
static int notrace blkz_pstore_write(struct pstore_record *record)
{
struct blkz_context *cxt = record->psi->data;
@@ -536,6 +693,8 @@ static int notrace blkz_pstore_write(struct pstore_record *record)
switch (record->type) {
case PSTORE_TYPE_DMESG:
return blkz_dmesg_write(cxt, record);
+ case PSTORE_TYPE_PMSG:
+ return blkz_pmsg_write(cxt, record);
default:
return -EINVAL;
}
@@ -552,6 +711,13 @@ static struct blkz_zone *blkz_read_next_zone(struct blkz_context *cxt)
return zone;
}
+ if (cxt->pmsg_read_cnt == 0) {
+ cxt->pmsg_read_cnt++;
+ zone = cxt->pbz;
+ if (blkz_old_ok(zone))
+ return zone;
+ }
+
return NULL;
}
@@ -590,7 +756,8 @@ static ssize_t blkz_dmesg_read(struct blkz_zone *zone,
char *buf = kasprintf(GFP_KERNEL,
"%s: Total %d times\n",
record->reason == KMSG_DUMP_OOPS ? "Oops" :
- "Panic", record->count);
+ record->reason == KMSG_DUMP_PANIC ? "Panic" :
+ "Unknown", record->count);
hlen = strlen(buf);
record->buf = krealloc(buf, hlen + size, GFP_KERNEL);
if (!record->buf) {
@@ -612,6 +779,29 @@ static ssize_t blkz_dmesg_read(struct blkz_zone *zone,
return size + hlen;
}
+static ssize_t blkz_pmsg_read(struct blkz_zone *zone,
+ struct pstore_record *record)
+{
+ size_t size, start;
+ struct blkz_buffer *buf;
+
+ buf = (struct blkz_buffer *)zone->oldbuf;
+ if (!buf)
+ return READ_NEXT_ZONE;
+
+ size = atomic_read(&buf->datalen);
+ start = atomic_read(&buf->start);
+
+ record->buf = kmalloc(size, GFP_KERNEL);
+ if (!record->buf)
+ return -ENOMEM;
+
+ memcpy(record->buf, buf->data + start, size - start);
+ memcpy(record->buf + size - start, buf->data, start);
+
+ return size;
+}
+
static ssize_t blkz_pstore_read(struct pstore_record *record)
{
struct blkz_context *cxt = record->psi->data;
@@ -637,6 +827,9 @@ static ssize_t blkz_pstore_read(struct pstore_record *record)
blkz_read = blkz_dmesg_read;
record->id = cxt->dmesg_read_cnt - 1;
break;
+ case PSTORE_TYPE_PMSG:
+ blkz_read = blkz_pmsg_read;
+ break;
default:
goto next_zone;
}
@@ -750,8 +943,10 @@ static struct blkz_zone *blkz_init_zone(enum pstore_type_id type,
zone->type = type;
zone->buffer_size = size - sizeof(struct blkz_buffer);
zone->buffer->sig = type ^ BLK_SIG;
+ zone->oldbuf = NULL;
atomic_set(&zone->dirty, 0);
atomic_set(&zone->buffer->datalen, 0);
+ atomic_set(&zone->buffer->start, 0);
*off += size;
@@ -833,7 +1028,7 @@ static int blkz_cut_zones(struct blkz_context *cxt)
int err;
size_t size;
- size = info->part_size;
+ size = info->part_size - info->pmsg_size;
cxt->dbzs = blkz_init_zones(PSTORE_TYPE_DMESG, &off, size,
info->dmesg_size, &cxt->dmesg_max_cnt);
if (IS_ERR(cxt->dbzs)) {
@@ -841,7 +1036,16 @@ static int blkz_cut_zones(struct blkz_context *cxt)
goto fail_out;
}
+ size = info->pmsg_size;
+ cxt->pbz = blkz_init_zone(PSTORE_TYPE_PMSG, &off, size);
+ if (IS_ERR(cxt->pbz)) {
+ err = PTR_ERR(cxt->pbz);
+ goto free_dmesg_zones;
+ }
+
return 0;
+free_dmesg_zones:
+ blkz_free_zones(&cxt->dbzs, &cxt->dmesg_max_cnt);
fail_out:
return err;
}
@@ -852,7 +1056,7 @@ int blkz_register(struct blkz_info *info)
struct blkz_context *cxt = &blkz_cxt;
struct module *owner = info->owner;
- if (!info->part_size || !info->dmesg_size) {
+ if (!info->part_size || (!info->dmesg_size && !info->pmsg_size)) {
pr_warn("The memory size and the dmesg size must be non-zero\n");
return -EINVAL;
}
@@ -872,6 +1076,7 @@ int blkz_register(struct blkz_info *info)
check_size(part_size, 4096);
check_size(dmesg_size, SECTOR_SIZE);
+ check_size(pmsg_size, SECTOR_SIZE);
#undef check_size
@@ -898,20 +1103,25 @@ int blkz_register(struct blkz_info *info)
goto fail_out;
}
- cxt->pstore.bufsize = cxt->dbzs[0]->buffer_size -
+ if (info->dmesg_size) {
+ cxt->pstore.bufsize = cxt->dbzs[0]->buffer_size -
sizeof(struct blkz_dmesg_header);
- cxt->pstore.buf = kzalloc(cxt->pstore.bufsize, GFP_KERNEL);
- if (!cxt->pstore.buf) {
- pr_err("cannot allocate pstore crash dump buffer\n");
- err = -ENOMEM;
- goto fail_out;
+ cxt->pstore.buf = kzalloc(cxt->pstore.bufsize, GFP_KERNEL);
+ if (!cxt->pstore.buf) {
+ err = -ENOMEM;
+ goto fail_out;
+ }
}
cxt->pstore.data = cxt;
- cxt->pstore.flags = PSTORE_FLAGS_DMESG;
+ if (info->dmesg_size)
+ cxt->pstore.flags |= PSTORE_FLAGS_DMESG;
+ if (info->pmsg_size)
+ cxt->pstore.flags |= PSTORE_FLAGS_PMSG;
- pr_info("Registered %s as blkzone backend for %s%s\n", info->name,
+ pr_info("Registered %s as blkzone backend for %s%s%s\n", info->name,
cxt->dbzs && cxt->bzinfo->dump_oops ? "Oops " : "",
- cxt->dbzs && cxt->bzinfo->panic_write ? "Panic " : "");
+ cxt->dbzs && cxt->bzinfo->panic_write ? "Panic " : "",
+ cxt->pbz ? "Pmsg" : "");
err = pstore_register(&cxt->pstore);
if (err) {
@@ -945,7 +1155,7 @@ void blkz_unregister(struct blkz_info *info)
spin_unlock(&cxt->bzinfo_lock);
blkz_free_zones(&cxt->dbzs, &cxt->dmesg_max_cnt);
-
+ blkz_free_zone(&cxt->pbz);
}
EXPORT_SYMBOL_GPL(blkz_unregister);
diff --git a/include/linux/pstore_blk.h b/include/linux/pstore_blk.h
index 27b282d..bcd8afb 100644
--- a/include/linux/pstore_blk.h
+++ b/include/linux/pstore_blk.h
@@ -48,6 +48,7 @@ struct blkz_info {
const char *part_path;
unsigned long part_size;
unsigned long dmesg_size;
+ unsigned long pmsg_size;
int dump_oops;
ssize_t (*read)(char *buf, size_t bytes, loff_t pos);
ssize_t (*write)(const char *buf, size_t bytes, loff_t pos);
--
1.9.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* [RFC v8 5/5] Documentation: pstore/blk: create document for pstore_blk
2019-02-13 14:07 [RFC v8 0/5] pstore/block: new support logger for block devices liaoweixiong
` (3 preceding siblings ...)
2019-02-13 14:07 ` [RFC v8 4/5] pstore/blk: support pmsg for pstore block liaoweixiong
@ 2019-02-13 14:07 ` liaoweixiong
4 siblings, 0 replies; 6+ messages in thread
From: liaoweixiong @ 2019-02-13 14:07 UTC (permalink / raw)
To: Kees Cook, Anton Vorontsov, Colin Cross, Tony Luck,
Jonathan Corbet, Rob Herring, Mark Rutland, liaoweixiong,
Mauro Carvalho Chehab, David S. Miller, Greg Kroah-Hartman,
Nicolas Ferre, Arnd Bergmann
Cc: linux-doc, linux-kernel, devicetree
The document, at Documentation/admin-guide/pstore-block.rst,
tells user how to use pstore_blk and the attentions about panic
read/write
Signed-off-by: liaoweixiong <liaoweixiong@allwinnertech.com>
---
Documentation/admin-guide/pstore-block.rst | 227 +++++++++++++++++++++++++++++
MAINTAINERS | 1 +
fs/pstore/Kconfig | 4 +
3 files changed, 232 insertions(+)
create mode 100644 Documentation/admin-guide/pstore-block.rst
diff --git a/Documentation/admin-guide/pstore-block.rst b/Documentation/admin-guide/pstore-block.rst
new file mode 100644
index 0000000..4bb8c4c
--- /dev/null
+++ b/Documentation/admin-guide/pstore-block.rst
@@ -0,0 +1,227 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Pstore block oops/panic logger
+==============================
+
+Introduction
+------------
+
+Pstore block (pstore_blk) is an oops/panic logger that write its logs to block
+device before the system crashes. Pstore_blk needs block device driver
+registering a partition path of the block device, like /dev/mmcblk0p7 for mmc
+driver, and read/write APIs for this partition when on panic.
+
+Pstore block concepts
+---------------------
+
+Pstore block begins at function ``blkz_register``, by which block driver
+registers to pstore_blk. Recomemd that, block driver should register to
+pstore_blk after block device is ready. Block driver transfers a structure
+``blkz_info`` which is defined in *linux/pstore_blk.h*.
+
+The following key members of ``struct blkz_info`` may be of interest to you.
+
+part_path
+~~~~~~~~~
+
+The path of partition used for pstore_blk. It may be ``/dev/mmcblk[N]p[M]`` for
+mmc, and ``/dev/mtdblock[N]`` for mtd device.
+
+The ``part_path`` is not necessarily if you self-defined general read/write APIs
+on ``blkz_info``. In other words, the ``part_path`` is only used (by function
+blkz_default_general_read/write) when general read/write APIs are not defined.
+
+See more on section **read/write**.
+
+part_size
+~~~~~~~~~
+
+The total size in bytes of partition used for pstore_blk. This member **MUST**
+be effective and a multiple of 4096. It is recommended to 1M or larger for block
+device.
+
+The block device area is divided into many chunks, and each event writes
+a chunk of information.
+
+dmesg_size
+~~~~~~~~~~
+
+The chunk size in bytes for dmesg(oops/panic). It **MUST** be a multiple of
+SECTOR_SIZE (Most of the time, the SECTOR_SIZE is 512). If you don't need dmesg,
+you are safely to set it to 0.
+
+NOTE that, the remaining space, except ``pmsg_size`` and others, belongs to
+dmesg. It means that there are multiple chunks for dmesg.
+
+Psotre_blk will log to dmesg chunks one by one, and always overwrite the oldest
+chunk if no free chunk.
+
+pmsg_size
+~~~~~~~~~
+
+The chunk size in bytes for pmsg. It **MUST** be a multiple of SECTOR_SIZE (Most
+of the time, the SECTOR_SIZE is 512). If you don't need pmsg, you are safely to
+set it to 0.
+
+There is only one chunk for pmsg.
+
+Pmsg is a user space accessible pstore object. Writes to */dev/pmsg0* are
+appended to the chunk. On reboot the contents are available in
+/sys/fs/pstore/pmsg-pstore-blk-0.
+
+dump_oops
+~~~~~~~~~
+
+Dumping both oopses and panics can be done by setting 1 in the ``dump_oops``
+member while setting 0 in that variable dumps only the panics.
+
+read/write
+~~~~~~~~~~
+
+They are general ``read/write`` APIs. It is safely and recommended to ignore it,
+but set ``part_path``.
+
+These general APIs are used all the time expect panic. The ``read`` API is
+usually used to recover data from block device, and the ``write`` API is usually
+to flush new data and erase to block device.
+
+Pstore_blk will temporarily hold all new data before block device is ready. If
+you ignore both of ``read/write`` and ``part_path``, the old data will not be
+recovered and the new data will not be flushed until panic, using panic APIs.
+If you don't have panic APIs neither, all the data will be dropped when reboot.
+
+NOTE that, the general APIs must check whether the block device is ready if
+self-defined.
+
+panic_read/panic_write
+~~~~~~~~~~~~~~~~~~~~~~
+
+They are ``read/write`` APIs for panic. They are likely to general
+``read/write`` but will be used only when on panic.
+
+The attentions for panic read/write see section
+**Attentions in panic read/write APIs**.
+
+Register to pstore block
+------------------------
+
+Block device driver call ``blkz_register`` to register to Psotre_blk.
+For example:
+
+.. code-block:: c
+
+ #include <linux/pstore_blk.h>
+ [...]
+
+ static ssize_t XXXX_panic_read(char *buf, size bytes, loff_t pos)
+ {
+ [...]
+ }
+
+ static ssize_t XXXX_panic_write(const char *buf, size_t bytes, loff_t pos)
+ {
+ [...]
+ }
+
+ struct blkz_info XXXX_info = {
+ .onwer = THIS_MODULE,
+ .name = <...>,
+ .dmesg_size = <...>,
+ .pmsg_size = <...>,
+ .dump_oops = true,
+ .panic_read = XXXX_panic_read,
+ .panic_write = XXXX_panic_write,
+ };
+
+ static int __init XXXX_init(void)
+ {
+ [... get partition information ...]
+ XXXX_info.part_path = <...>;
+ XXXX_info.part_size = <...>;
+
+ [...]
+ return blkz_register(&XXXX_info);
+ }
+
+There are multiple ways by which you can get partition information.
+
+A. Use the module parameters and kernel cmdline.
+B. Use Device Tree bindings.
+C. Use Kconfig.
+D. Use Driver Feature.
+ For example, traverse all MTD device by ``register_mtd_user``, and get the
+ matching name MTD partition.
+
+NOTE that, all of above are done by block driver rather then pstore_blk. You can
+get sample on blkoops.
+
+The attentions for panic read/write see section
+**Attentions in panic read/write APIs**.
+
+Compression and header
+----------------------
+
+Block device is large enough, it is not necessary to compress dmesg data.
+Actually, we recommend not compress. Because pstore_blk will insert some
+information into the first line of dmesg data if no compression.
+For example::
+
+ Panic: Total 16 times
+
+It means that it's the 16th times panic log since burning.
+Sometimes, the oops|panic counter since burning is very important for embedded
+device to judge whether the system is stable.
+
+The follow line is insert by pstore filesystem.
+For example::
+
+ Oops#2 Part1
+
+It means that it's the 2nd times oops log on last booting.
+
+Reading the data
+----------------
+
+The dump data can be read from the pstore filesystem. The format for these
+files is ``dmesg-pstore-blk-[N]`` for dmesg(oops|panic) and
+``pmsg-pstore-blk-0`` for pmsg, where N is the record number. To delete a stored
+record from block device, simply unlink the respective pstore file. The
+timestamp of the dump file records the trigger time.
+
+Attentions in panic read/write APIs
+-----------------------------------
+
+If on panic, the kernel is not going to be running for much longer. The tasks
+will not be scheduled and the most kernel resources will be out of service. It
+looks like a single-threaded program running on a single-core computer.
+
+The following points need special attention for panic read/write APIs:
+
+1. Can **NOT** allocate any memory.
+
+ If you need memory, just allocate while the block driver is initialing rather
+ than waiting until the panic.
+
+2. Must be polled, **NOT** interrupt driven.
+
+ No task schedule any more. The block driver should delay to ensure the write
+ succeeds, but NOT sleep.
+
+3. Can **NOT** take any lock.
+
+ There is no other task, no any share resource, you are safely to break all
+ locks.
+
+4. Just use cpu to transfer.
+
+ Do not use DMA to transfer unless you are sure that DMA will not keep lock.
+
+5. Operate register directly.
+
+ Try not to use linux kernel resources. Do io map while initialing rather than
+ waiting until the panic.
+
+6. Reset your block device and controller if necessary.
+
+ If you are not sure the state of you block device and controller when panic,
+ you are safely to stop and reset them.
diff --git a/MAINTAINERS b/MAINTAINERS
index 44647a8..4dd95d3 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -12317,6 +12317,7 @@ F: include/linux/pstore*
F: drivers/firmware/efi/efi-pstore.c
F: drivers/acpi/apei/erst.c
F: Documentation/admin-guide/ramoops.rst
+F: Documentation/admin-guide/pstore-block.rst
F: Documentation/devicetree/bindings/reserved-memory/ramoops.txt
F: Documentation/devicetree/bindings/pstore-block/
K: \b(pstore|ramoops|blkoops)
diff --git a/fs/pstore/Kconfig b/fs/pstore/Kconfig
index f0a1a49..c32f66c 100644
--- a/fs/pstore/Kconfig
+++ b/fs/pstore/Kconfig
@@ -160,6 +160,10 @@ config PSTORE_BLK
This enables panic and oops message to be logged to a block dev
where it can be read back at some later point.
+ For more information, see Documentation/admin-guide/pstore-block.rst.
+
+ If unsure, say N.
+
config PSTORE_BLKOOPS
tristate "pstore block with oops logger"
depends on PSTORE_BLK
--
1.9.1
^ permalink raw reply related [flat|nested] 6+ messages in thread