From 480c696bb0f3253c9a53d9c2be2e29e1e5dffdc6 Mon Sep 17 00:00:00 2001
From: Torvald Riegel <triegel@redhat.com>
Date: Thu, 20 Jun 2013 16:40:54 +0000
Subject: [PATCH] libitm: Handle HTM fastpath in status query functions.

	* query.cc (_ITM_inTransaction): Abort when using the HTM fastpath.
	(_ITM_getTransactionId): Same.
	* config/x86/target.h (htm_transaction_active): New.

From-SVN: r200251
---
 libitm/ChangeLog           |  6 ++++++
 libitm/config/x86/target.h |  7 +++++++
 libitm/query.cc            | 14 ++++++++++++++
 3 files changed, 27 insertions(+)

diff --git a/libitm/ChangeLog b/libitm/ChangeLog
index 26001b670bd..81e5b6f447b 100644
--- a/libitm/ChangeLog
+++ b/libitm/ChangeLog
@@ -1,3 +1,9 @@
+2013-06-20  Torvald Riegel  <triegel@redhat.com>
+
+	* query.cc (_ITM_inTransaction): Abort when using the HTM fastpath.
+	(_ITM_getTransactionId): Same.
+	* config/x86/target.h (htm_transaction_active): New.
+
 2013-06-20  Torvald Riegel  <triegel@redhat.com>
 
 	PR libitm/57643
diff --git a/libitm/config/x86/target.h b/libitm/config/x86/target.h
index 77b627f95bb..063c09ed974 100644
--- a/libitm/config/x86/target.h
+++ b/libitm/config/x86/target.h
@@ -125,6 +125,13 @@ htm_abort_should_retry (uint32_t begin_ret)
 {
   return begin_ret & _XABORT_RETRY;
 }
+
+/* Returns true iff a hardware transaction is currently being executed.  */
+static inline bool
+htm_transaction_active ()
+{
+  return _xtest() != 0;
+}
 #endif
 
 
diff --git a/libitm/query.cc b/libitm/query.cc
index 5707321f6c2..39a35b3e3b9 100644
--- a/libitm/query.cc
+++ b/libitm/query.cc
@@ -43,6 +43,15 @@ _ITM_libraryVersion (void)
 _ITM_howExecuting ITM_REGPARM
 _ITM_inTransaction (void)
 {
+#if defined(USE_HTM_FASTPATH)
+  // If we use the HTM fastpath, we cannot reliably detect whether we are
+  // in a transaction because this function can be called outside of
+  // a transaction and thus we can't deduce this by looking at just the serial
+  // lock.  This function isn't used in practice currently, so the easiest
+  // way to handle it is to just abort.
+  if (htm_fastpath && htm_transaction_active())
+    htm_abort();
+#endif
   struct gtm_thread *tx = gtm_thr();
   if (tx && (tx->nesting > 0))
     {
@@ -58,6 +67,11 @@ _ITM_inTransaction (void)
 _ITM_transactionId_t ITM_REGPARM
 _ITM_getTransactionId (void)
 {
+#if defined(USE_HTM_FASTPATH)
+  // See ITM_inTransaction.
+  if (htm_fastpath && htm_transaction_active())
+    htm_abort();
+#endif
   struct gtm_thread *tx = gtm_thr();
   return (tx && (tx->nesting > 0)) ? tx->id : _ITM_noTransactionId;
 }