tools lib traceevent: Add more debugging to see various internal ring buffer entries

When trace-cmd report --debug is set, show the internal ring buffer
entries like time-extends and padding. This requires adding new kbuffer
API to retrieve these items.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Tzvetomir Stoyanov <tstoyanov@vmware.com>
Link: http://lkml.kernel.org/r/20190401164343.257591565@goodmis.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 49 insertions, 0 deletions

diff --git a/tools/lib/traceevent/kbuffer-parse.c b/tools/lib/traceevent/kbuffer-parse.c
index af2a1f3b7424..b887e7437d67 100644
--- a/tools/lib/traceevent/kbuffer-parse.c
+++ b/tools/lib/traceevent/kbuffer-parse.c
@@ -727,3 +727,52 @@ int kbuffer_start_of_data(struct kbuffer *kbuf)
 {
         return kbuf->start;
 }
+
+/**
+ * kbuffer_raw_get - get raw buffer info
+ * @kbuf:       The kbuffer
+ * @subbuf:     Start of mapped subbuffer
+ * @info:       Info descriptor to fill in
+ *
+ * For debugging. This can return internals of the ring buffer.
+ * Expects to have info->next set to what it will read.
+ * The type, length and timestamp delta will be filled in, and
+ * @info->next will be updated to the next element.
+ * The @subbuf is used to know if the info is passed the end of
+ * data and NULL will be returned if it is.
+ */
+struct kbuffer_raw_info *
+kbuffer_raw_get(struct kbuffer *kbuf, void *subbuf, struct kbuffer_raw_info *info)
+{
+        unsigned long long flags;
+        unsigned long long delta;
+        unsigned int type_len;
+        unsigned int size;
+        int start;
+        int length;
+        void *ptr = info->next;
+
+        if (!kbuf || !subbuf)
+                return NULL;
+
+        if (kbuf->flags & KBUFFER_FL_LONG_8)
+                start = 16;
+        else
+                start = 12;
+
+        flags = read_long(kbuf, subbuf + 8);
+        size = (unsigned int)flags & COMMIT_MASK;
+
+        if (ptr < subbuf || ptr >= subbuf + start + size)
+                return NULL;
+
+        type_len = translate_data(kbuf, ptr, &ptr, &delta, &length);
+
+        info->next = ptr + length;
+
+        info->type = type_len;
+        info->delta = delta;
+        info->length = length;
+
+        return info;
+}