[PATCH v2.1 13/12] xen/trace: Introduce new API

[Andrew Cooper <andrew.cooper3@citrix.com>]

This will be used to clean up mess of macros which exists throughout the
codebase.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: George Dunlap <George.Dunlap@eu.citrix.com>
CC: Ian Jackson <iwj@xenproject.org>
CC: Jan Beulich <JBeulich@suse.com>
CC: Stefano Stabellini <sstabellini@kernel.org>
CC: Wei Liu <wl@xen.org>
CC: Julien Grall <julien@xen.org>

v2.1:
 * New
---
 xen/include/xen/trace.h | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/xen/include/xen/trace.h b/xen/include/xen/trace.h
index 055883287e8c..72c20550f6a6 100644
--- a/xen/include/xen/trace.h
+++ b/xen/include/xen/trace.h
@@ -74,6 +74,30 @@ static inline void __trace_hypercall(uint32_t event, unsigned long op,
                                      const xen_ulong_t *args) {}
 #endif /* CONFIG_TRACEBUFFER */
 
+/*
+ * Create a trace record, packaging up to 7 additional parameters into a
+ * uint32_t array.
+ */
+#define TRACE_INTERNAL(_e, _c, ...)                                     \
+    do {                                                                \
+        if ( unlikely(tb_init_done) )                                   \
+        {                                                               \
+            uint32_t _d[] = { __VA_ARGS__ };                            \
+            BUILD_BUG_ON(ARRAY_SIZE(_d) > TRACE_EXTRA_MAX);             \
+            __trace_var(_e, _c, sizeof(_d), sizeof(_d) ? _d : NULL);    \
+        }                                                               \
+    } while ( 0 )
+
+/* Split a uint64_t into two adjacent uint32_t's for a trace record. */
+#define TRACE_PARAM64(p)    (uint32_t)(p), ((p) >> 32)
+
+/* Create a trace record with time included. */
+#define TRACE_TIME(_e, ...) TRACE_INTERNAL(_e, true,  ##__VA_ARGS__)
+
+/* Create a trace record with no time included. */
+#define TRACE(_e, ...)      TRACE_INTERNAL(_e, false, ##__VA_ARGS__)
+
+
 /* Convenience macros for calling the trace function. */
 #define TRACE_0D(_e)                            \
     do {                                        \
-- 
2.11.0