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Date: Wed, 23 Jan 2019 19:11:10 +0800
From: 廖威雄 <liaoweixiong@...winnertech.com>
To: Kees Cook <keescook@...omium.org>
Cc: Anton Vorontsov <anton@...msg.org>,
Colin Cross <ccross@...roid.com>,
Tony Luck <tony.luck@...el.com>,
Jonathan Corbet <corbet@....net>,
Mauro Carvalho Chehab <mchehab+samsung@...nel.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
"David S. Miller" <davem@...emloft.net>,
Andrew Morton <akpm@...ux-foundation.org>,
Nicolas Ferre <nicolas.ferre@...rochip.com>,
Arnd Bergmann <arnd@...db.de>,
"open list:DOCUMENTATION" <linux-doc@...r.kernel.org>,
LKML <linux-kernel@...r.kernel.org>
Subject: Re: [RFC v5 3/4] pstore/blk: support pmsg for pstore block
On 2019-01-18 08:17, Kees Cook wrote:
> On Mon, Jan 7, 2019 at 4:01 AM liaoweixiong
> <liaoweixiong@...winnertech.com> wrote:
>>
>> To enable pmsg, just set pmsg_size when block device register blkzone.
>
> At first pass, this looks like a reasonable extension of blkzone. Is
> it possible to add console, ftrace, etc, too?
>
I plan to do that on other patch, because i am going to refine the
public codes for all extensions before add console, ftrace, etc. It
takes some time.
> -Kees
>
>>
>> Signed-off-by: liaoweixiong <liaoweixiong@...winnertech.com>
>> ---
>> fs/pstore/blkzone.c | 254 +++++++++++++++++++++++++++++++++++++++++----
>> include/linux/pstore_blk.h | 1 +
>> 2 files changed, 233 insertions(+), 22 deletions(-)
>>
>> diff --git a/fs/pstore/blkzone.c b/fs/pstore/blkzone.c
>> index e1b7f26..157f1cfd 100644
>> --- a/fs/pstore/blkzone.c
>> +++ b/fs/pstore/blkzone.c
>> @@ -32,12 +32,14 @@
>> *
>> * @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[0];
>> };
>>
>> @@ -70,6 +72,9 @@ 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:
>> @@ -83,6 +88,7 @@ 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;
>> @@ -90,8 +96,10 @@ struct blkz_zone {
>>
>> struct blkoops_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
>> @@ -125,6 +133,11 @@ 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 blkoops_context *cxt = &blkz_cxt;
>> @@ -394,6 +407,72 @@ static int blkz_recover_dmesg(struct blkoops_context *cxt)
>> return ret;
>> }
>>
>> +static int blkz_recover_pmsg(struct blkoops_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("recovery 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 blkoops_context *cxt)
>> {
>> int ret = -EBUSY;
>> @@ -408,6 +487,10 @@ static inline int blkz_recovery(struct blkoops_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;
>> @@ -425,11 +508,18 @@ static int blkoops_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 blkoops_pstore_erase(struct pstore_record *record)
>> @@ -443,13 +533,29 @@ static int blkoops_pstore_erase(struct pstore_record *record)
>> */
>> blkz_recovery(cxt);
>>
>> - 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 blkoops_write_kmsg_hdr(struct blkz_zone *zone,
>> @@ -467,8 +573,10 @@ static void blkoops_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 blkoops_context *cxt,
>> @@ -518,6 +626,55 @@ static int notrace blkz_dmesg_write(struct blkoops_context *cxt,
>> return 0;
>> }
>>
>> +static int notrace blkz_pmsg_write(struct blkoops_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 blkoops_pstore_write(struct pstore_record *record)
>> {
>> struct blkoops_context *cxt = record->psi->data;
>> @@ -535,6 +692,8 @@ static int notrace blkoops_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;
>> }
>> @@ -551,6 +710,13 @@ static struct blkz_zone *blkz_read_next_zone(struct blkoops_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;
>> }
>>
>> @@ -589,7 +755,8 @@ static ssize_t blkz_dmesg_read(struct blkz_zone *zone,
>> char *buf = kasprintf(GFP_KERNEL,
>> "blkoops: %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) {
>> @@ -611,6 +778,29 @@ 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 blkoops_pstore_read(struct pstore_record *record)
>> {
>> struct blkoops_context *cxt = record->psi->data;
>> @@ -642,6 +832,9 @@ static ssize_t blkoops_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;
>> }
>> @@ -754,8 +947,10 @@ 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;
>>
>> @@ -837,7 +1032,7 @@ static int blkz_cut_zones(struct blkoops_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)) {
>> @@ -845,7 +1040,16 @@ static int blkz_cut_zones(struct blkoops_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;
>> }
>> @@ -856,7 +1060,7 @@ int blkz_register(struct blkz_info *info)
>> struct blkoops_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;
>> }
>> @@ -876,6 +1080,7 @@ int blkz_register(struct blkz_info *info)
>>
>> check_size(part_size, 4096 - 1);
>> check_size(dmesg_size, SECTOR_SIZE - 1);
>> + check_size(pmsg_size, SECTOR_SIZE - 1);
>>
>> #undef check_size
>>
>> @@ -902,16 +1107,20 @@ 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;
>>
>> err = pstore_register(&cxt->pstore);
>> if (err) {
>> @@ -919,9 +1128,10 @@ int blkz_register(struct blkz_info *info)
>> goto free_pstore_buf;
>> }
>>
>> - 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" : "");
>>
>> module_put(owner);
>> return 0;
>> @@ -949,7 +1159,7 @@ 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 426cae4..6c6b4eb 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
>>
>
>
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