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 <joelaf@google.com>
[kees: clarified variables names, added -ENOMEM handling]
Signed-off-by: Kees Cook <keescook@chromium.org>
diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
index 0ed3fec..f5d2661 100644
--- a/fs/pstore/ram.c
+++ b/fs/pstore/ram.c
@@ -182,16 +182,69 @@
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 @@
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)) {
- while (cxt->ftrace_read_cnt < cxt->max_ftrace_cnt && !prz) {
- prz = ramoops_get_next_prz(cxt->fprzs,
- &cxt->ftrace_read_cnt,
- cxt->max_ftrace_cnt, id, type,
- PSTORE_TYPE_FTRACE, 0);
- if (!prz_ok(prz))
- continue;
- }
- }
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;
+
+ /* ftrace is last since it may want to dynamically allocate memory. */
+ if (!prz_ok(prz)) {
+ if (!(cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU)) {
+ prz = ramoops_get_next_prz(cxt->fprzs,
+ &cxt->ftrace_read_cnt, 1, id, type,
+ PSTORE_TYPE_FTRACE, 0);
+ } 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)) {
+ size = 0;
+ goto out;
+ }
size = persistent_ram_old_size(prz) - header_length;
@@ -244,12 +331,21 @@
*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;
}