From 4158a15a59fc6efbbbc99d66107fb4e1f27f9664 Mon Sep 17 00:00:00 2001
From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Thu, 1 Mar 2012 12:13:47 -0500
Subject: [PATCH] Fix: fixup vtid TLS

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Conflicts:

	liblttng-ust/lttng-context-vtid.c
---
 liblttng-ust/ltt-tracer-core.h    | 1 +
 liblttng-ust/lttng-context-vtid.c | 9 +++++++++
 liblttng-ust/lttng-ust-comm.c     | 1 +
 3 files changed, 11 insertions(+)

diff --git a/liblttng-ust/ltt-tracer-core.h b/liblttng-ust/ltt-tracer-core.h
index 7fdf3c9e..2ea4eadf 100644
--- a/liblttng-ust/ltt-tracer-core.h
+++ b/liblttng-ust/ltt-tracer-core.h
@@ -38,5 +38,6 @@ void ust_lock(void);
 void ust_unlock(void);
 
 void lttng_fixup_event_tls(void);
+void lttng_fixup_vtid_tls(void);
 
 #endif /* _LTT_TRACER_CORE_H */
diff --git a/liblttng-ust/lttng-context-vtid.c b/liblttng-ust/lttng-context-vtid.c
index 6f7e078d..22261f55 100644
--- a/liblttng-ust/lttng-context-vtid.c
+++ b/liblttng-ust/lttng-context-vtid.c
@@ -12,6 +12,7 @@
 #include <lttng/ust-events.h>
 #include <lttng/ust-tracer.h>
 #include <lttng/ringbuffer-config.h>
+#include "ltt-tracer-core.h"
 
 #ifdef __linux__
 #include <syscall.h>
@@ -92,3 +93,11 @@ int lttng_add_vtid_to_ctx(struct lttng_ctx **ctx)
 	field->record = vtid_record;
 	return 0;
 }
+
+/*
+ * Force a read (imply TLS fixup for dlopen) of TLS variables.
+ */
+void lttng_fixup_vtid_tls(void)
+{
+	asm volatile ("" : : "m" (cached_vtid));
+}
diff --git a/liblttng-ust/lttng-ust-comm.c b/liblttng-ust/lttng-ust-comm.c
index b90df861..e19fa949 100644
--- a/liblttng-ust/lttng-ust-comm.c
+++ b/liblttng-ust/lttng-ust-comm.c
@@ -840,6 +840,7 @@ void __attribute__((constructor)) lttng_ust_init(void)
 	 */
 	lttng_fixup_event_tls();
 	lttng_fixup_ringbuffer_tls();
+	lttng_fixup_vtid_tls();
 
 	/*
 	 * We want precise control over the order in which we construct
-- 
2.34.1