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SubjectRe: [PATCH v2 04/11] pstore/blk: blkoops: support console recorder
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hi Kees Cook,

On 2020/3/19 AM 2:16, Kees Cook wrote:
> On Fri, Feb 07, 2020 at 08:25:48PM +0800, WeiXiong Liao wrote:
>> Support recorder for console. To enable console recorder, just make
>> console_size be greater than 0 and a multiple of 4096.
>>
>> Signed-off-by: WeiXiong Liao <liaoweixiong@allwinnertech.com>
>> ---
>> fs/pstore/Kconfig | 12 ++++++
>> fs/pstore/blkoops.c | 11 +++++
>> fs/pstore/blkzone.c | 101 ++++++++++++++++++++++++++++++++++-----------
>> include/linux/blkoops.h | 6 ++-
>> include/linux/pstore_blk.h | 8 +++-
>> 5 files changed, 112 insertions(+), 26 deletions(-)
>>
>> diff --git a/fs/pstore/Kconfig b/fs/pstore/Kconfig
>> index bbf1fdb5eaa7..5f0a42823028 100644
>> --- a/fs/pstore/Kconfig
>> +++ b/fs/pstore/Kconfig
>> @@ -198,6 +198,18 @@ config PSTORE_BLKOOPS_PMSG_SIZE
>> NOTE that, both kconfig and module parameters can configure blkoops,
>> but module parameters have priority over kconfig.
>>
>> +config PSTORE_BLKOOPS_CONSOLE_SIZE
>> + int "console size in kbytes for blkoops"
>> + depends on PSTORE_BLKOOPS
>> + depends on PSTORE_CONSOLE
>> + default 64
>
> Same tricks here as for the PMSG.
>

Same reply as for the PMSG.

>> + help
>> + This just sets size of console (console_size) for pstore/blk. The
>> + size is in KB and must be a multiple of 4.
>> +
>> + NOTE that, both kconfig and module parameters can configure blkoops,
>> + but module parameters have priority over kconfig.
>> +
>> config PSTORE_BLKOOPS_BLKDEV
>> string "block device for blkoops"
>> depends on PSTORE_BLKOOPS
>> diff --git a/fs/pstore/blkoops.c b/fs/pstore/blkoops.c
>> index 02e6e4c1f965..05990bc3b168 100644
>> --- a/fs/pstore/blkoops.c
>> +++ b/fs/pstore/blkoops.c
>> @@ -20,6 +20,10 @@
>> module_param(pmsg_size, long, 0400);
>> MODULE_PARM_DESC(pmsg_size, "pmsg size in kbytes");
>>
>> +static long console_size = -1;
>> +module_param(console_size, long, 0400);
>> +MODULE_PARM_DESC(console_size, "console size in kbytes");
>> +
>> static int dump_oops = -1;
>> module_param(dump_oops, int, 0400);
>> MODULE_PARM_DESC(total_size, "whether dump oops");
>> @@ -70,6 +74,12 @@
>> #define DEFAULT_PMSG_SIZE 0
>> #endif
>>
>> +#ifdef CONFIG_PSTORE_BLKOOPS_CONSOLE_SIZE
>> +#define DEFAULT_CONSOLE_SIZE CONFIG_PSTORE_BLKOOPS_CONSOLE_SIZE
>> +#else
>> +#define DEFAULT_CONSOLE_SIZE 0
>> +#endif
>> +
>> #ifdef CONFIG_PSTORE_BLKOOPS_DUMP_OOPS
>> #define DEFAULT_DUMP_OOPS CONFIG_PSTORE_BLKOOPS_DUMP_OOPS
>> #else
>> @@ -124,6 +134,7 @@ int blkoops_register_device(struct blkoops_device *bo_dev)
>>
>> verify_size(dmesg_size, DEFAULT_DMESG_SIZE, 4096);
>> verify_size(pmsg_size, DEFAULT_PMSG_SIZE, 4096);
>> + verify_size(console_size, DEFAULT_CONSOLE_SIZE, 4096);
>> #undef verify_size
>> dump_oops = !!(dump_oops < 0 ? DEFAULT_DUMP_OOPS : dump_oops);
>>
>> diff --git a/fs/pstore/blkzone.c b/fs/pstore/blkzone.c
>> index a3464252d52e..9a7e9b06ccf7 100644
>> --- a/fs/pstore/blkzone.c
>> +++ b/fs/pstore/blkzone.c
>> @@ -88,9 +88,11 @@ struct blkz_zone {
>> struct blkz_context {
>> struct blkz_zone **dbzs; /* dmesg block zones */
>> struct blkz_zone *pbz; /* Pmsg block zone */
>> + struct blkz_zone *cbz; /* console block zone */
>> unsigned int dmesg_max_cnt;
>> unsigned int dmesg_read_cnt;
>> unsigned int pmsg_read_cnt;
>> + unsigned int console_read_cnt;
>> unsigned int dmesg_write_cnt;
>> /*
>> * the counter should be recovered when recover.
>> @@ -111,6 +113,9 @@ struct blkz_context {
>> };
>> static struct blkz_context blkz_cxt;
>>
>> +static void blkz_flush_all_dirty_zones(struct work_struct *);
>> +static DECLARE_WORK(blkz_cleaner, blkz_flush_all_dirty_zones);
>> +
>> enum blkz_flush_mode {
>> FLUSH_NONE = 0,
>> FLUSH_PART,
>> @@ -200,6 +205,9 @@ static int blkz_zone_write(struct blkz_zone *zone,
>> return 0;
>> set_dirty:
>> atomic_set(&zone->dirty, true);
>> + /* flush dirty zones nicely */
>> + if (wcnt == -EBUSY && !is_on_panic())
>> + schedule_work(&blkz_cleaner);
>> return -EBUSY;
>> }
>>
>> @@ -266,6 +274,15 @@ static int blkz_move_zone(struct blkz_zone *old, struct blkz_zone *new)
>> return 0;
>> }
>>
>> +static void blkz_flush_all_dirty_zones(struct work_struct *work)
>> +{
>> + struct blkz_context *cxt = &blkz_cxt;
>> +
>> + blkz_flush_dirty_zone(cxt->pbz);
>> + blkz_flush_dirty_zone(cxt->cbz);
>> + blkz_flush_dirty_zones(cxt->dbzs, cxt->dmesg_max_cnt);
>> +}
>> +
>> static int blkz_recover_dmesg_data(struct blkz_context *cxt)
>> {
>> struct blkz_info *info = cxt->bzinfo;
>> @@ -419,15 +436,13 @@ static int blkz_recover_dmesg(struct blkz_context *cxt)
>> return ret;
>> }
>>
>> -static int blkz_recover_pmsg(struct blkz_context *cxt)
>> +static int blkz_recover_zone(struct blkz_context *cxt, struct blkz_zone *zone)
>> {
>> struct blkz_info *info = cxt->bzinfo;
>> struct blkz_buffer *oldbuf;
>> - struct blkz_zone *zone = NULL;
>> int ret = 0;
>> ssize_t rcnt, len;
>>
>> - zone = cxt->pbz;
>> if (!zone || zone->oldbuf)
>> return 0;
>>
>> @@ -493,7 +508,11 @@ static inline int blkz_recovery(struct blkz_context *cxt)
>> if (ret)
>> goto recover_fail;
>>
>> - ret = blkz_recover_pmsg(cxt);
>> + ret = blkz_recover_zone(cxt, cxt->pbz);
>> + if (ret)
>> + goto recover_fail;
>> +
>> + ret = blkz_recover_zone(cxt, cxt->cbz);
>> if (ret)
>> goto recover_fail;
>>
>> @@ -512,6 +531,7 @@ static int blkz_pstore_open(struct pstore_info *psi)
>>
>> cxt->dmesg_read_cnt = 0;
>> cxt->pmsg_read_cnt = 0;
>> + cxt->console_read_cnt = 0;
>> return 0;
>> }
>>
>> @@ -539,7 +559,7 @@ static inline int blkz_dmesg_erase(struct blkz_context *cxt,
>> return blkz_zone_write(zone, FLUSH_META, NULL, 0, 0);
>> }
>>
>> -static inline int blkz_pmsg_erase(struct blkz_context *cxt,
>> +static inline int blkz_record_erase(struct blkz_context *cxt,
>> struct blkz_zone *zone)
>> {
>> if (unlikely(!blkz_old_ok(zone)))
>> @@ -566,9 +586,10 @@ static int blkz_pstore_erase(struct pstore_record *record)
>> case PSTORE_TYPE_DMESG:
>> return blkz_dmesg_erase(cxt, cxt->dbzs[record->id]);
>> case PSTORE_TYPE_PMSG:
>> - return blkz_pmsg_erase(cxt, cxt->pbz);
>> - default:
>> - return -EINVAL;
>> + return blkz_record_erase(cxt, cxt->pbz);
>> + case PSTORE_TYPE_CONSOLE:
>> + return blkz_record_erase(cxt, cxt->cbz);
>> + default: return -EINVAL;
>> }
>> }
>>
>> @@ -653,17 +674,15 @@ 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)
>> +static int notrace blkz_record_write(struct blkz_context *cxt,
>> + struct blkz_zone *zone, struct pstore_record *record)
>
> How about generalizing this earlier in the patch series instead of
> mutating it here?
>

OK.

>> {
>> - 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)
>> + if (!zone || !record)
>> return -ENOSPC;
>>
>> if (atomic_read(&zone->buffer->datalen) >= zone->buffer_size)
>> @@ -710,11 +729,20 @@ static int notrace blkz_pstore_write(struct pstore_record *record)
>> record->reason == KMSG_DUMP_PANIC)
>> atomic_set(&cxt->on_panic, 1);
>>
>> + /*
>> + * if on panic, do not write except dmesg records
>> + * Fix case that panic_write prints log which wakes up console recorder.
>> + */
>> + if (is_on_panic() && record->type != PSTORE_TYPE_DMESG)
>> + return -EBUSY;
>> +
>> switch (record->type) {
>> case PSTORE_TYPE_DMESG:
>> return blkz_dmesg_write(cxt, record);
>> + case PSTORE_TYPE_CONSOLE:
>> + return blkz_record_write(cxt, cxt->cbz, record);
>> case PSTORE_TYPE_PMSG:
>> - return blkz_pmsg_write(cxt, record);
>> + return blkz_record_write(cxt, cxt->pbz, record);
>> default:
>> return -EINVAL;
>> }
>> @@ -738,6 +766,13 @@ static struct blkz_zone *blkz_read_next_zone(struct blkz_context *cxt)
>> return zone;
>> }
>>
>> + if (cxt->console_read_cnt == 0) {
>> + cxt->console_read_cnt++;
>> + zone = cxt->cbz;
>> + if (blkz_old_ok(zone))
>> + return zone;
>> + }
>> +
>> return NULL;
>> }
>>
>> @@ -799,7 +834,7 @@ static ssize_t blkz_dmesg_read(struct blkz_zone *zone,
>> return size + hlen;
>> }
>>
>> -static ssize_t blkz_pmsg_read(struct blkz_zone *zone,
>> +static ssize_t blkz_record_read(struct blkz_zone *zone,
>> struct pstore_record *record)
>> {
>> size_t size, start;
>> @@ -825,7 +860,7 @@ static ssize_t blkz_pmsg_read(struct blkz_zone *zone,
>> 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,
>> + ssize_t (*readop)(struct blkz_zone *zone,
>> struct pstore_record *record);
>> struct blkz_zone *zone;
>> ssize_t ret;
>> @@ -843,17 +878,19 @@ static ssize_t blkz_pstore_read(struct pstore_record *record)
>> record->type = zone->type;
>> switch (record->type) {
>> case PSTORE_TYPE_DMESG:
>> - blkz_read = blkz_dmesg_read;
>> + readop = blkz_dmesg_read;
>> record->id = cxt->dmesg_read_cnt - 1;
>> break;
>> + case PSTORE_TYPE_CONSOLE:
>> + /* fallthrough */
>
> Since this case has no body, you can leave off the "fallthrough". (But
> if you want to mark it anyway, please use "fallthrough;" instead of a
> comment.)
>

OK. I will fix it anywhere.

>> case PSTORE_TYPE_PMSG:
>> - blkz_read = blkz_pmsg_read;
>> + readop = blkz_record_read;
>> break;
>> default:
>> goto next_zone;
>> }
>>
>> - ret = blkz_read(zone, record);
>> + ret = readop(zone, record);
>> if (ret == READ_NEXT_ZONE)
>> goto next_zone;
>> return ret;
>> @@ -1001,15 +1038,25 @@ static int blkz_cut_zones(struct blkz_context *cxt)
>> goto fail_out;
>> }
>>
>> + off_size += info->console_size;
>> + cxt->cbz = blkz_init_zone(PSTORE_TYPE_CONSOLE, &off,
>> + info->console_size);
>> + if (IS_ERR(cxt->cbz)) {
>> + err = PTR_ERR(cxt->cbz);
>> + goto free_pmsg;
>> + }
>> +
>> cxt->dbzs = blkz_init_zones(PSTORE_TYPE_DMESG, &off,
>> info->total_size - off_size,
>> info->dmesg_size, &cxt->dmesg_max_cnt);
>> if (IS_ERR(cxt->dbzs)) {
>> err = PTR_ERR(cxt->dbzs);
>> - goto free_pmsg;
>> + goto free_console;
>> }
>>
>> return 0;
>> +free_console:
>> + blkz_free_zone(&cxt->cbz);
>> free_pmsg:
>> blkz_free_zone(&cxt->pbz);
>> fail_out:
>> @@ -1027,7 +1074,7 @@ int blkz_register(struct blkz_info *info)
>> return -EINVAL;
>> }
>>
>> - if (!info->dmesg_size && !info->pmsg_size) {
>> + if (!info->dmesg_size && !info->pmsg_size && !info->console_size) {
>> pr_warn("at least one of the records be non-zero\n");
>> return -EINVAL;
>> }
>> @@ -1055,6 +1102,7 @@ int blkz_register(struct blkz_info *info)
>> check_size(total_size, 4096);
>> check_size(dmesg_size, SECTOR_SIZE);
>> check_size(pmsg_size, SECTOR_SIZE);
>> + check_size(console_size, SECTOR_SIZE);
>>
>> #undef check_size
>>
>> @@ -1087,6 +1135,7 @@ int blkz_register(struct blkz_info *info)
>> pr_debug("\ttotal size : %ld Bytes\n", info->total_size);
>> pr_debug("\tdmesg size : %ld Bytes\n", info->dmesg_size);
>> pr_debug("\tpmsg size : %ld Bytes\n", info->pmsg_size);
>> + pr_debug("\tconsole size : %ld Bytes\n", info->console_size);
>>
>> err = blkz_cut_zones(cxt);
>> if (err) {
>> @@ -1108,11 +1157,15 @@ int blkz_register(struct blkz_info *info)
>> cxt->pstore.flags |= PSTORE_FLAGS_DMESG;
>> if (info->pmsg_size)
>> cxt->pstore.flags |= PSTORE_FLAGS_PMSG;
>> + if (info->console_size)
>> + cxt->pstore.flags |= PSTORE_FLAGS_CONSOLE;
>>
>> - pr_info("Registered %s as blkzone backend for %s%s%s\n", info->name,
>> + pr_info("Registered %s as blkzone backend for %s%s%s%s\n",
>> + info->name,
>> cxt->dbzs && cxt->bzinfo->dump_oops ? "Oops " : "",
>> cxt->dbzs && cxt->bzinfo->panic_write ? "Panic " : "",
>> - cxt->pbz ? "Pmsg" : "");
>> + cxt->pbz ? "Pmsg " : "",
>> + cxt->cbz ? "Console" : "");
>>
>> err = pstore_register(&cxt->pstore);
>> if (err) {
>> @@ -1139,6 +1192,8 @@ void blkz_unregister(struct blkz_info *info)
>> {
>> struct blkz_context *cxt = &blkz_cxt;
>>
>> + flush_work(&blkz_cleaner);
>> +
>> pstore_unregister(&cxt->pstore);
>> kfree(cxt->pstore.buf);
>> cxt->pstore.bufsize = 0;
>> diff --git a/include/linux/blkoops.h b/include/linux/blkoops.h
>> index fe63739309aa..8f40f225545d 100644
>> --- a/include/linux/blkoops.h
>> +++ b/include/linux/blkoops.h
>> @@ -23,8 +23,10 @@
>> * Both of the @size and @offset parameters on this interface are
>> * the relative size of the space provided, not the whole disk/flash.
>> *
>> - * On success, the number of bytes read should be returned.
>> - * On error, negative number should be returned.
>> + * On success, the number of bytes read/write should be returned.
>> + * On error, negative number should be returned. The following returning
>> + * number means more:
>> + * -EBUSY: pstore/blk should try again later.
>> * @panic_write:
>> * The write operation only used for panic.
>> *
>> diff --git a/include/linux/pstore_blk.h b/include/linux/pstore_blk.h
>> index af06be25bd01..546375e04419 100644
>> --- a/include/linux/pstore_blk.h
>> +++ b/include/linux/pstore_blk.h
>> @@ -22,6 +22,9 @@
>> * @pmsg_size:
>> * The size of zone for pmsg. Zero means disabled, othewise, it must be
>> * multiple of SECTOR_SIZE(512).
>> + * @console_size:
>> + * The size of zone for console. Zero means disabled, othewise, it must
>> + * be multiple of SECTOR_SIZE(512).
>> * @dump_oops:
>> * Dump oops and panic log or only panic.
>> * @read, @write:
>> @@ -33,7 +36,9 @@
>> * the relative size of the space provided, not the whole disk/flash.
>> *
>> * On success, the number of bytes read/write should be returned.
>> - * On error, negative number should be returned.
>> + * On error, negative number should be returned. The following returning
>> + * number means more:
>> + * -EBUSY: pstore/blk should try again later.
>> * @panic_write:
>> * The write operation only used for panic. It's optional if you do not
>> * care panic record. If panic occur but blkzone do not recover yet, the
>> @@ -54,6 +59,7 @@ struct blkz_info {
>> unsigned long total_size;
>> unsigned long dmesg_size;
>> unsigned long pmsg_size;
>> + unsigned long console_size;
>> int dump_oops;
>> blkz_read_op read;
>> blkz_write_op write;
>> --
>> 1.9.1
>>
>

--
WeiXiong Liao

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