1 files changed, 47 insertions, 0 deletions

diff --git a/include/litmus/signal.h b/include/litmus/signal.h
new file mode 100644
index 000000000000..b3d82b294984
--- /dev/null
+++ b/include/litmus/signal.h
@@ -0,0 +1,47 @@
+#ifndef LITMUS_SIGNAL_H
+#define LITMUS_SIGNAL_H
+
+#ifdef __KERNEL__
+#include <linux/signal.h>
+#else
+#include <signal.h>
+#endif
+
+/* Signals used by Litmus to asynchronously communicate events
+ * to real-time tasks.
+ * 
+ * Signal values overlap with [SIGRTMIN, SIGRTMAX], so beware of
+ * application-level conflicts when dealing with COTS user-level
+ * code.
+ */
+
+/* Sent to a Litmus task when all of the following conditions are true:
+ * (1) The task has exhausted its budget.
+ * (2) budget_signal_policy is QUANTUM_SIGNALS or PRECISE_SIGNALS.
+ *
+ * Note: If a task does not have a registered handler for SIG_BUDGET,
+ * the signal will cause the task to terminate (default action).
+ */
+
+/* Assigned values start at SIGRTMAX and decrease, hopefully reducing
+ * likelihood of user-level conflicts.
+ */
+#define SIG_BUDGET                                      (SIGRTMAX - 0)
+
+/*
+Future signals could include:
+
+#define SIG_DEADLINE_MISS                       (SIGRTMAX - 1)
+#define SIG_CRIT_LEVEL_CHANGE           (SIGRTMAX - 2)
+*/
+
+#define SIGLITMUSMIN                            SIG_BUDGET
+
+#ifdef __KERNEL__
+#if (SIGLITMUSMIN < SIGRTMIN)
+/* no compile-time check in user-space since SIGRTMIN may be a variable. */
+#error "Too many LITMUS^RT signals!"
+#endif
+#endif
+
+#endif