From: Marc Zyngier <marc.zyngier@arm.com>
Date: Tue, 14 Feb 2012 11:25:58 +0000 (+0000)
Subject: ARM: local timers: reserve local_timer_register() to SMP
X-Git-Tag: firefly_0821_release~3680^2~2860^2~2^2^2~6
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=bfa05f4f3398b61205567f3a5cad90804a5a1fdc;p=firefly-linux-kernel-4.4.55.git

ARM: local timers: reserve local_timer_register() to SMP

When running an SMP_ON_UP enabled kernel on UP, or with nosmp
passed to the kernel, we want to be able to detect that a local
timer is not going to be used (local timers are only used on
SMP platforms), so we could register it as a global timer instead.

Return -ENXIO when the above case is detected.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---

diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index addbbe8028c2..11c4148b8abb 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -454,6 +454,9 @@ static struct local_timer_ops *lt_ops;
 #ifdef CONFIG_LOCAL_TIMERS
 int local_timer_register(struct local_timer_ops *ops)
 {
+	if (!is_smp() || !setup_max_cpus)
+		return -ENXIO;
+
 	if (lt_ops)
 		return -EBUSY;