Introduce Virtio-loopback epsilon release:

Epsilon release introduces a new compatibility layer which make virtio-loopback
design to work with QEMU and rust-vmm vhost-user backend without require any
changes.

Signed-off-by: Timos Ampelikiotis <t.ampelikiotis@virtualopensystems.com>
Change-Id: I52e57563e08a7d0bdc002f8e928ee61ba0c53dd9

1 files changed, 55 insertions, 0 deletions

diff --git a/scripts/tracetool/backend/ftrace.py b/scripts/tracetool/backend/ftrace.py
new file mode 100644
index 000000000..5fa30ccc0
--- /dev/null
+++ b/scripts/tracetool/backend/ftrace.py
@@ -0,0 +1,55 @@
+# -*- coding: utf-8 -*-
+
+"""
+Ftrace built-in backend.
+"""
+
+__author__     = "Eiichi Tsukata <eiichi.tsukata.xh@hitachi.com>"
+__copyright__  = "Copyright (C) 2013 Hitachi, Ltd."
+__license__    = "GPL version 2 or (at your option) any later version"
+
+__maintainer__ = "Stefan Hajnoczi"
+__email__      = "stefanha@redhat.com"
+
+
+from tracetool import out
+
+
+PUBLIC = True
+
+
+def generate_h_begin(events, group):
+    out('#include "trace/ftrace.h"',
+        '')
+
+
+def generate_h(event, group):
+    argnames = ", ".join(event.args.names())
+    if len(event.args) > 0:
+        argnames = ", " + argnames
+
+    out('    {',
+        '        char ftrace_buf[MAX_TRACE_STRLEN];',
+        '        int unused __attribute__ ((unused));',
+        '        int trlen;',
+        '        if (trace_event_get_state(%(event_id)s)) {',
+        '#line %(event_lineno)d "%(event_filename)s"',
+        '            trlen = snprintf(ftrace_buf, MAX_TRACE_STRLEN,',
+        '                             "%(name)s " %(fmt)s "\\n" %(argnames)s);',
+        '#line %(out_next_lineno)d "%(out_filename)s"',
+        '            trlen = MIN(trlen, MAX_TRACE_STRLEN - 1);',
+        '            unused = write(trace_marker_fd, ftrace_buf, trlen);',
+        '        }',
+        '    }',
+        name=event.name,
+        args=event.args,
+        event_id="TRACE_" + event.name.upper(),
+        event_lineno=event.lineno,
+        event_filename=event.filename,
+        fmt=event.fmt.rstrip("\n"),
+        argnames=argnames)
+
+
+def generate_h_backend_dstate(event, group):
+    out('    trace_event_get_state_dynamic_by_id(%(event_id)s) || \\',
+        event_id="TRACE_" + event.name.upper())