From: Chris Redpath <chris.redpath@arm.com>
Date: Mon, 25 Jul 2016 14:13:58 +0000 (+0100)
Subject: arch_timer: add error handling when the MPM global timer is cleared
X-Git-Tag: firefly_0821_release~176^2~204
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=7bba794daaa85dce327e52b201439bb2c148b6c9;p=firefly-linux-kernel-4.4.55.git

arch_timer: add error handling when the MPM global timer is cleared

Bug: 29000863
Signed-off-by: albert.zl_huang <albert.zl_huang@htc.com>
Change-Id: I2b5a28b0a9edb31bdaa1ca2310397dd2f36f6c23

Updated to use arch_timer_read_counter() as arch_counter_get_cntvct
doesn't exist in this kernel.

Signed-off-by: Chris Redpath <chris.redpath@arm.com>
---

diff --git a/kernel/sched/walt.c b/kernel/sched/walt.c
index b9ae8d5c4393..d9d09914ce30 100644
--- a/kernel/sched/walt.c
+++ b/kernel/sched/walt.c
@@ -185,7 +185,14 @@ update_window_start(struct rq *rq, u64 wallclock)
 	int nr_windows;
 
 	delta = wallclock - rq->window_start;
-	BUG_ON(delta < 0);
+	/* If the MPM global timer is cleared, set delta as 0 to avoid kernel BUG happening */
+	if (delta < 0) {
+		if (arch_timer_read_counter() == 0)
+			delta = 0;
+		else
+			BUG_ON(1);
+	}
+
 	if (delta < walt_ravg_window)
 		return;