From 079da6afc3903ecd5f0c2a6afbab513bc348e1f2 Mon Sep 17 00:00:00 2001
From: Stefan Lankes <slankes@eonerc.rwth-aachen.de>
Date: Thu, 3 Aug 2017 07:48:39 +0200
Subject: [PATCH] remove mwait support to avoid priority inversion

---
 arch/x86/kernel/tasks.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/x86/kernel/tasks.c b/arch/x86/kernel/tasks.c
index d063662d8..81d38aeca 100644
--- a/arch/x86/kernel/tasks.c
+++ b/arch/x86/kernel/tasks.c
@@ -195,6 +195,9 @@ int create_default_frame(task_t* task, entry_point_t ep, void* arg, uint32_t cor
 
 void wait_for_task(void)
 {
+#if 1
+	HALT;
+#else
 	if (!has_mwait()) {
 		HALT;
 	} else {
@@ -206,13 +209,16 @@ void wait_for_task(void)
 		monitor(queue, 0, 0);
 		mwait(0x2 /* 0x2 = c3, 0xF = c0 */, 1 /* break on interrupt flag */);
 	}
+#endif
 }
 
 void wakeup_core(uint32_t core_id)
 {
+#if 0
 	// if mwait is available, an IPI isn't required to wakeup the core
 	if (has_mwait())
 		return;
+#endif
 
 	// no self IPI required
 	if (core_id == CORE_ID)