From 0ffc89ee30372debea4b09c903350d256e213c85 Mon Sep 17 00:00:00 2001
From: Stefan Kalkowski <stefan.kalkowski@genode-labs.com>
Date: Wed, 27 Aug 2014 11:00:24 +0200
Subject: [PATCH] hw: clrex during context switch (Fixes #1196)

---
 repos/base-hw/src/core/spec/arm_v7/mode_transition.s | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/repos/base-hw/src/core/spec/arm_v7/mode_transition.s b/repos/base-hw/src/core/spec/arm_v7/mode_transition.s
index 7566b9768..ad41f5a8c 100644
--- a/repos/base-hw/src/core/spec/arm_v7/mode_transition.s
+++ b/repos/base-hw/src/core/spec/arm_v7/mode_transition.s
@@ -369,6 +369,13 @@
 	add sp, sp, #PSR_OFFSET
 	stm sp, {r0, r1}
 
+	/*
+	 * Clear exclusive access in local monitor,
+	 * as we use strex/ldrex in our cmpxchg method, we've to do this during
+	 * a context switch (ARM Reference Manual paragraph 3.4.4.)
+	 */
+	clrex
+
 	/*********************************************************
 	 ** Kernel-entry code that is common for all exceptions **
 	 *********************************************************/