From 99b223a2c7185cabe274af63eec6dfcbec83c6db Mon Sep 17 00:00:00 2001
From: Glenn Elliott <gelliott@cs.unc.edu>
Date: Fri, 27 Sep 2013 14:13:45 -0400
Subject: Add PGM support.

Adds routines for userspace tasks to use to communicate their
state to the Litmus kernel.
---
 include/litmus.h   |  4 ++++
 src/kernel_iface.c | 36 ++++++++++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+)

diff --git a/include/litmus.h b/include/litmus.h
index dc0d0bf..2817373 100644
--- a/include/litmus.h
+++ b/include/litmus.h
@@ -123,6 +123,10 @@ void enter_np(void);
 void exit_np(void);
 int  requested_to_preempt(void);
 
+/* pgm support */
+void enter_pgm_wait(void);
+void exit_pgm_wait(void);
+
 /* task system support */
 int wait_for_ts_release(void);
 int release_ts(lt_t *delay);
diff --git a/src/kernel_iface.c b/src/kernel_iface.c
index ca874ff..3fe4f60 100644
--- a/src/kernel_iface.c
+++ b/src/kernel_iface.c
@@ -140,6 +140,42 @@ int requested_to_preempt(void)
 	return (likely(ctrl_page != NULL) && ctrl_page->sched.np.preempt);
 }
 
+
+void enter_pgm_wait(void)
+{
+	if (likely(ctrl_page != NULL) || init_kernel_iface() == 0) {
+		if (!ctrl_page->pgm_waiting) {
+			ctrl_page->pgm_waiting = 1;
+			__sync_synchronize();
+		}
+	}
+	else {
+		fprintf(stderr, "enter_pgm_wait: control page not mapped!\n");
+	}
+}
+
+void exit_pgm_wait(void)
+{
+	if (likely(ctrl_page != NULL)) {
+		if (ctrl_page->pgm_waiting) {
+			ctrl_page->pgm_satisfied = 1;
+			__sync_synchronize();
+
+			/* re-eval priority. Should clear pgm_waiting and pgm_satisfied */
+			sched_yield();
+
+			if (ctrl_page->pgm_waiting || ctrl_page->pgm_satisfied) {
+				fprintf(stderr, "exit_pgm_wait: pgm flags not cleared! "
+					"waiting:%d satisfied:%d\n",
+					ctrl_page->pgm_waiting, ctrl_page->pgm_satisfied);
+			}
+		}
+	}
+	else {
+		fprintf(stderr, "exit_pgm_wait: control page not mapped!\n");
+	}
+}
+
 /* init and return a ptr to the control page for
  * preemption and migration overhead analysis
  *
-- 
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