pstore/zone,blk: Add ftrace frontend support

Support backend for ftrace. To enable ftrace backend, just make
ftrace_size be greater than 0 and a multiple of 4096.

Signed-off-by: WeiXiong Liao <liaoweixiong@allwinnertech.com>
Link: https://lore.kernel.org/lkml/20200511233229.27745-6-keescook@chromium.org/
Co-developed-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/lkml/20200512170719.221514-1-colin.king@canonical.com
Signed-off-by: Kees Cook <keescook@chromium.org>

diff --git a/fs/pstore/Kconfig b/fs/pstore/Kconfig
index 126aa6c3ecf243cec4d73ad1ab784163fcf35b84..c2237984b407d895032de0c24858a0b54b45e05e 100644 (file)
--- a/fs/pstore/Kconfig
+++ b/fs/pstore/Kconfig
@@ -248,3 +248,15 @@ config PSTORE_BLK_CONSOLE_SIZE
 
          NOTE that, both Kconfig and module parameters can configure
          pstore/blk, but module parameters have priority over Kconfig.
+
+config PSTORE_BLK_FTRACE_SIZE
+       int "Size in Kbytes of ftrace log to store"
+       depends on PSTORE_BLK
+       depends on PSTORE_FTRACE
+       default 64
+       help
+         This just sets size of ftrace log (ftrace_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
+         pstore/blk, but module parameters have priority over Kconfig.

diff --git a/fs/pstore/blk.c b/fs/pstore/blk.c
index 082f6cdaf4bd75ee9c20175ff94fcc4f656effa6..e0d95fb4842873661ad7cead2be3ac5903d0e259 100644 (file)
--- a/fs/pstore/blk.c
+++ b/fs/pstore/blk.c
@@ -43,6 +43,14 @@ static long console_size = -1;
 module_param(console_size, long, 0400);
 MODULE_PARM_DESC(console_size, "console size in kbytes");
 
+#if IS_ENABLED(CONFIG_PSTORE_FTRACE)
+static long ftrace_size = CONFIG_PSTORE_BLK_FTRACE_SIZE;
+#else
+static long ftrace_size = -1;
+#endif
+module_param(ftrace_size, long, 0400);
+MODULE_PARM_DESC(ftrace_size, "ftrace size in kbytes");
+
 /*
  * blkdev - the block device to use for pstore storage
  *
@@ -152,6 +160,7 @@ static int psblk_register_do(struct pstore_device_info *dev)
        verify_size(kmsg_size, 4096, dev->flags & PSTORE_FLAGS_DMESG);
        verify_size(pmsg_size, 4096, dev->flags & PSTORE_FLAGS_PMSG);
        verify_size(console_size, 4096, dev->flags & PSTORE_FLAGS_CONSOLE);
+       verify_size(ftrace_size, 4096, dev->flags & PSTORE_FLAGS_FTRACE);
 #undef verify_size
 
        pstore_zone_info->total_size = dev->total_size;

diff --git a/fs/pstore/zone.c b/fs/pstore/zone.c
index ee0b64da410d3a50cdb926c08ef5edd4dd24c547..2d9f452360bb2e51682e28e40ab99fb2fb924fab 100644 (file)
--- a/fs/pstore/zone.c
+++ b/fs/pstore/zone.c
@@ -92,11 +92,14 @@ struct pstore_zone {
  * @kpszs: kmsg dump storage zones
  * @ppsz: pmsg storage zone
  * @cpsz: console storage zone
+ * @fpszs: ftrace storage zones
  * @kmsg_max_cnt: max count of @kpszs
  * @kmsg_read_cnt: counter of total read kmsg dumps
  * @kmsg_write_cnt: counter of total kmsg dump writes
  * @pmsg_read_cnt: counter of total read pmsg zone
  * @console_read_cnt: counter of total read console zone
+ * @ftrace_max_cnt: max count of @fpszs
+ * @ftrace_read_cnt: counter of max read ftrace zone
  * @oops_counter: counter of oops dumps
  * @panic_counter: counter of panic dumps
  * @recovered: whether finished recovering data from storage
@@ -109,11 +112,14 @@ struct psz_context {
        struct pstore_zone **kpszs;
        struct pstore_zone *ppsz;
        struct pstore_zone *cpsz;
+       struct pstore_zone **fpszs;
        unsigned int kmsg_max_cnt;
        unsigned int kmsg_read_cnt;
        unsigned int kmsg_write_cnt;
        unsigned int pmsg_read_cnt;
        unsigned int console_read_cnt;
+       unsigned int ftrace_max_cnt;
+       unsigned int ftrace_read_cnt;
        /*
         * These counters should be calculated during recovery.
         * It records the oops/panic times after crashes rather than boots.
@@ -314,6 +320,8 @@ static void psz_flush_all_dirty_zones(struct work_struct *work)
                ret |= psz_flush_dirty_zone(cxt->cpsz);
        if (cxt->kpszs)
                ret |= psz_flush_dirty_zones(cxt->kpszs, cxt->kmsg_max_cnt);
+       if (cxt->fpszs)
+               ret |= psz_flush_dirty_zones(cxt->fpszs, cxt->ftrace_max_cnt);
        if (ret && cxt->pstore_zone_info)
                schedule_delayed_work(&psz_cleaner, msecs_to_jiffies(1000));
 }
@@ -550,6 +558,31 @@ free_oldbuf:
        return ret;
 }
 
+static int psz_recover_zones(struct psz_context *cxt,
+               struct pstore_zone **zones, unsigned int cnt)
+{
+       int ret;
+       unsigned int i;
+       struct pstore_zone *zone;
+
+       if (!zones)
+               return 0;
+
+       for (i = 0; i < cnt; i++) {
+               zone = zones[i];
+               if (unlikely(!zone))
+                       continue;
+               ret = psz_recover_zone(cxt, zone);
+               if (ret)
+                       goto recover_fail;
+       }
+
+       return 0;
+recover_fail:
+       pr_debug("recover %s[%u] failed\n", zone->name, i);
+       return ret;
+}
+
 /**
  * psz_recovery() - recover data from storage
  * @cxt: the context of pstore/zone
@@ -574,6 +607,10 @@ static inline int psz_recovery(struct psz_context *cxt)
                goto out;
 
        ret = psz_recover_zone(cxt, cxt->cpsz);
+       if (ret)
+               goto out;
+
+       ret = psz_recover_zones(cxt, cxt->fpszs, cxt->ftrace_max_cnt);
 
 out:
        if (unlikely(ret))
@@ -592,6 +629,7 @@ static int psz_pstore_open(struct pstore_info *psi)
        cxt->kmsg_read_cnt = 0;
        cxt->pmsg_read_cnt = 0;
        cxt->console_read_cnt = 0;
+       cxt->ftrace_read_cnt = 0;
        return 0;
 }
 
@@ -658,6 +696,10 @@ static int psz_pstore_erase(struct pstore_record *record)
                return psz_record_erase(cxt, cxt->ppsz);
        case PSTORE_TYPE_CONSOLE:
                return psz_record_erase(cxt, cxt->cpsz);
+       case PSTORE_TYPE_FTRACE:
+               if (record->id >= cxt->ftrace_max_cnt)
+                       return -EINVAL;
+               return psz_record_erase(cxt, cxt->fpszs[record->id]);
        default: return -EINVAL;
        }
 }
@@ -802,6 +844,13 @@ static int notrace psz_pstore_write(struct pstore_record *record)
                return psz_record_write(cxt->cpsz, record);
        case PSTORE_TYPE_PMSG:
                return psz_record_write(cxt->ppsz, record);
+       case PSTORE_TYPE_FTRACE: {
+               int zonenum = smp_processor_id();
+
+               if (!cxt->fpszs)
+                       return -ENOSPC;
+               return psz_record_write(cxt->fpszs[zonenum], record);
+       }
        default:
                return -EINVAL;
        }
@@ -817,6 +866,14 @@ static struct pstore_zone *psz_read_next_zone(struct psz_context *cxt)
                        return zone;
        }
 
+       if (cxt->ftrace_read_cnt < cxt->ftrace_max_cnt)
+               /*
+                * No need psz_old_ok(). Let psz_ftrace_read() do so for
+                * combination. psz_ftrace_read() should traverse over
+                * all zones in case of some zone without data.
+                */
+               return cxt->fpszs[cxt->ftrace_read_cnt++];
+
        if (cxt->pmsg_read_cnt == 0) {
                cxt->pmsg_read_cnt++;
                zone = cxt->ppsz;
@@ -891,6 +948,38 @@ static ssize_t psz_kmsg_read(struct pstore_zone *zone,
        return size + hlen;
 }
 
+/* try to combine all ftrace zones */
+static ssize_t psz_ftrace_read(struct pstore_zone *zone,
+               struct pstore_record *record)
+{
+       struct psz_context *cxt;
+       struct psz_buffer *buf;
+       int ret;
+
+       if (!zone || !record)
+               return -ENOSPC;
+
+       if (!psz_old_ok(zone))
+               goto out;
+
+       buf = (struct psz_buffer *)zone->oldbuf;
+       if (!buf)
+               return -ENOMSG;
+
+       ret = pstore_ftrace_combine_log(&record->buf, &record->size,
+                       (char *)buf->data, atomic_read(&buf->datalen));
+       if (unlikely(ret))
+               return ret;
+
+out:
+       cxt = record->psi->data;
+       if (cxt->ftrace_read_cnt < cxt->ftrace_max_cnt)
+               /* then, read next ftrace zone */
+               return -ENOMSG;
+       record->id = 0;
+       return record->size ? record->size : -ENOMSG;
+}
+
 static ssize_t psz_record_read(struct pstore_zone *zone,
                struct pstore_record *record)
 {
@@ -941,6 +1030,9 @@ next_zone:
                readop = psz_kmsg_read;
                record->id = cxt->kmsg_read_cnt - 1;
                break;
+       case PSTORE_TYPE_FTRACE:
+               readop = psz_ftrace_read;
+               break;
        case PSTORE_TYPE_CONSOLE:
                fallthrough;
        case PSTORE_TYPE_PMSG:
@@ -1005,6 +1097,8 @@ static void psz_free_all_zones(struct psz_context *cxt)
                psz_free_zone(&cxt->ppsz);
        if (cxt->cpsz)
                psz_free_zone(&cxt->cpsz);
+       if (cxt->fpszs)
+               psz_free_zones(&cxt->fpszs, &cxt->ftrace_max_cnt);
 }
 
 static struct pstore_zone *psz_init_zone(enum pstore_type_id type,
@@ -1115,6 +1209,17 @@ static int psz_alloc_zones(struct psz_context *cxt)
                goto free_out;
        }
 
+       off_size += info->ftrace_size;
+       cxt->fpszs = psz_init_zones(PSTORE_TYPE_FTRACE, &off,
+                       info->ftrace_size,
+                       info->ftrace_size / nr_cpu_ids,
+                       &cxt->ftrace_max_cnt);
+       if (IS_ERR(cxt->fpszs)) {
+               err = PTR_ERR(cxt->fpszs);
+               cxt->fpszs = NULL;
+               goto free_out;
+       }
+
        cxt->kpszs = psz_init_zones(PSTORE_TYPE_DMESG, &off,
                        info->total_size - off_size,
                        info->kmsg_size, &cxt->kmsg_max_cnt);
@@ -1149,7 +1254,8 @@ int register_pstore_zone(struct pstore_zone_info *info)
                return -EINVAL;
        }
 
-       if (!info->kmsg_size && !info->pmsg_size && !info->console_size) {
+       if (!info->kmsg_size && !info->pmsg_size && !info->console_size &&
+           !info->ftrace_size) {
                pr_warn("at least one record size must be non-zero\n");
                return -EINVAL;
        }
@@ -1173,6 +1279,7 @@ int register_pstore_zone(struct pstore_zone_info *info)
        check_size(kmsg_size, SECTOR_SIZE);
        check_size(pmsg_size, SECTOR_SIZE);
        check_size(console_size, SECTOR_SIZE);
+       check_size(ftrace_size, SECTOR_SIZE);
 
 #undef check_size
 
@@ -1200,6 +1307,7 @@ int register_pstore_zone(struct pstore_zone_info *info)
        pr_debug("\tkmsg size : %ld Bytes\n", info->kmsg_size);
        pr_debug("\tpmsg size : %ld Bytes\n", info->pmsg_size);
        pr_debug("\tconsole size : %ld Bytes\n", info->console_size);
+       pr_debug("\tftrace size : %ld Bytes\n", info->ftrace_size);
 
        err = psz_alloc_zones(cxt);
        if (err) {
@@ -1237,6 +1345,10 @@ int register_pstore_zone(struct pstore_zone_info *info)
                cxt->pstore.flags |= PSTORE_FLAGS_CONSOLE;
                pr_cont(" console");
        }
+       if (info->ftrace_size) {
+               cxt->pstore.flags |= PSTORE_FLAGS_FTRACE;
+               pr_cont(" ftrace");
+       }
        pr_cont("\n");
 
        err = pstore_register(&cxt->pstore);

diff --git a/include/linux/pstore_zone.h b/include/linux/pstore_zone.h
index 904ee67f4ba2b509e51e0524e0bd5acc656e496e..6f16b0dd834a8da9d2d3384e33abf5a60ce759a3 100644 (file)
--- a/include/linux/pstore_zone.h
+++ b/include/linux/pstore_zone.h
@@ -19,6 +19,7 @@ typedef ssize_t (*pstore_zone_write_op)(const char *, size_t, loff_t);
  * @max_reason: Maximum kmsg dump reason to store.
  * @pmsg_size: The size of pmsg zone which is the same as @kmsg_size.
  * @console_size:The size of console zone which is the same as @kmsg_size.
+ * @ftrace_size:The size of ftrace zone which is the same as @kmsg_size.
  * @read:      The general read operation. Both of the function parameters
  *             @size and @offset are relative value to storage.
  *             On success, the number of bytes should be returned, others
@@ -37,6 +38,7 @@ struct pstore_zone_info {
        int max_reason;
        unsigned long pmsg_size;
        unsigned long console_size;
+       unsigned long ftrace_size;
        pstore_zone_read_op read;
        pstore_zone_write_op write;
        pstore_zone_write_op panic_write;