From 2fbea82bbb893e07a6f5c23397a60ec9933e54b7 Mon Sep 17 00:00:00 2001 From: Joel Fernandes Date: Thu, 20 Oct 2016 00:34:06 -0700 Subject: [PATCH] pstore: Merge per-CPU ftrace records into one Up until this patch, each of the per CPU ftrace buffers appear as a separate ftrace-ramoops-N file. In this patch we merge all the zones into one and populate a single ftrace-ramoops-0 file. Signed-off-by: Joel Fernandes [kees: clarified variables names, added -ENOMEM handling] Signed-off-by: Kees Cook --- fs/pstore/ram.c | 122 ++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 109 insertions(+), 13 deletions(-) diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c index 0ed3fec04c9b..f5d266157964 100644 --- a/fs/pstore/ram.c +++ b/fs/pstore/ram.c @@ -182,16 +182,69 @@ static bool prz_ok(struct persistent_ram_zone *prz) persistent_ram_ecc_string(prz, NULL, 0)); } +static ssize_t ftrace_log_combine(struct persistent_ram_zone *dest, + struct persistent_ram_zone *src) +{ + size_t dest_size, src_size, total, dest_off, src_off; + size_t dest_idx = 0, src_idx = 0, merged_idx = 0; + void *merged_buf; + struct pstore_ftrace_record *drec, *srec, *mrec; + size_t record_size = sizeof(struct pstore_ftrace_record); + + dest_off = dest->old_log_size % record_size; + dest_size = dest->old_log_size - dest_off; + + src_off = src->old_log_size % record_size; + src_size = src->old_log_size - src_off; + + total = dest_size + src_size; + merged_buf = kmalloc(total, GFP_KERNEL); + if (!merged_buf) + return -ENOMEM; + + drec = (struct pstore_ftrace_record *)(dest->old_log + dest_off); + srec = (struct pstore_ftrace_record *)(src->old_log + src_off); + mrec = (struct pstore_ftrace_record *)(merged_buf); + + while (dest_size > 0 && src_size > 0) { + if (pstore_ftrace_read_timestamp(&drec[dest_idx]) < + pstore_ftrace_read_timestamp(&srec[src_idx])) { + mrec[merged_idx++] = drec[dest_idx++]; + dest_size -= record_size; + } else { + mrec[merged_idx++] = srec[src_idx++]; + src_size -= record_size; + } + } + + while (dest_size > 0) { + mrec[merged_idx++] = drec[dest_idx++]; + dest_size -= record_size; + } + + while (src_size > 0) { + mrec[merged_idx++] = srec[src_idx++]; + src_size -= record_size; + } + + kfree(dest->old_log); + dest->old_log = merged_buf; + dest->old_log_size = total; + + return 0; +} + static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type, int *count, struct timespec *time, char **buf, bool *compressed, ssize_t *ecc_notice_size, struct pstore_info *psi) { - ssize_t size; + ssize_t size = 0; struct ramoops_context *cxt = psi->data; struct persistent_ram_zone *prz = NULL; int header_length = 0; + bool free_prz = false; /* Ramoops headers provide time stamps for PSTORE_TYPE_DMESG, but * PSTORE_TYPE_CONSOLE and PSTORE_TYPE_FTRACE don't currently have @@ -221,22 +274,56 @@ static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type, if (!prz_ok(prz)) prz = ramoops_get_next_prz(&cxt->cprz, &cxt->console_read_cnt, 1, id, type, PSTORE_TYPE_CONSOLE, 0); + + if (!prz_ok(prz)) + prz = ramoops_get_next_prz(&cxt->mprz, &cxt->pmsg_read_cnt, + 1, id, type, PSTORE_TYPE_PMSG, 0); + + /* ftrace is last since it may want to dynamically allocate memory. */ if (!prz_ok(prz)) { - while (cxt->ftrace_read_cnt < cxt->max_ftrace_cnt && !prz) { + if (!(cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU)) { prz = ramoops_get_next_prz(cxt->fprzs, - &cxt->ftrace_read_cnt, - cxt->max_ftrace_cnt, id, type, + &cxt->ftrace_read_cnt, 1, id, type, PSTORE_TYPE_FTRACE, 0); - if (!prz_ok(prz)) - continue; + } else { + /* + * Build a new dummy record which combines all the + * per-cpu records including metadata and ecc info. + */ + struct persistent_ram_zone *tmp_prz, *prz_next; + + tmp_prz = kzalloc(sizeof(struct persistent_ram_zone), + GFP_KERNEL); + if (!tmp_prz) + return -ENOMEM; + free_prz = true; + + while (cxt->ftrace_read_cnt < cxt->max_ftrace_cnt) { + prz_next = ramoops_get_next_prz(cxt->fprzs, + &cxt->ftrace_read_cnt, + cxt->max_ftrace_cnt, id, + type, PSTORE_TYPE_FTRACE, 0); + + if (!prz_ok(prz_next)) + continue; + + tmp_prz->ecc_info = prz_next->ecc_info; + tmp_prz->corrected_bytes += + prz_next->corrected_bytes; + tmp_prz->bad_blocks += prz_next->bad_blocks; + size = ftrace_log_combine(tmp_prz, prz_next); + if (size) + goto out; + } + *id = 0; + prz = tmp_prz; } } - if (!prz_ok(prz)) - prz = ramoops_get_next_prz(&cxt->mprz, &cxt->pmsg_read_cnt, - 1, id, type, PSTORE_TYPE_PMSG, 0); - if (!prz_ok(prz)) - return 0; + if (!prz_ok(prz)) { + size = 0; + goto out; + } size = persistent_ram_old_size(prz) - header_length; @@ -244,12 +331,21 @@ static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type, *ecc_notice_size = persistent_ram_ecc_string(prz, NULL, 0); *buf = kmalloc(size + *ecc_notice_size + 1, GFP_KERNEL); - if (*buf == NULL) - return -ENOMEM; + if (*buf == NULL) { + size = -ENOMEM; + goto out; + } memcpy(*buf, (char *)persistent_ram_old(prz) + header_length, size); + persistent_ram_ecc_string(prz, *buf + size, *ecc_notice_size + 1); +out: + if (free_prz) { + kfree(prz->old_log); + kfree(prz); + } + return size; } -- 2.20.1