From e50eb5198be9ba5e629ab41c168bab15f462aa92 Mon Sep 17 00:00:00 2001
From: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
Date: Thu, 19 Apr 2018 12:34:04 +0530
Subject: [PATCH 5/9] powerpc64/ftrace: Disable ftrace during hotplug
References: bsc#1088804
Patch-mainline: v4.18-rc1
Git-commit: 424ef0160f439feb2a1a6e796a281e2bfa7b6997
Disable ftrace when a cpu is about to go offline. When the cpu is woken
up, ftrace will get enabled in start_secondary().
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
arch/powerpc/kernel/smp.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 0d50ca3aa876..182b68fc0cb9 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -1022,6 +1022,8 @@ int __cpu_disable(void)
if (!smp_ops->cpu_disable)
return -ENOSYS;
+ this_cpu_disable_ftrace();
+
err = smp_ops->cpu_disable();
if (err)
return err;
@@ -1047,6 +1049,12 @@ void __cpu_die(unsigned int cpu)
void cpu_die(void)
{
+ /*
+ * Disable on the down path. This will be re-enabled by
+ * start_secondary() via start_secondary_resume() below
+ */
+ this_cpu_disable_ftrace();
+
if (ppc_md.cpu_die)
ppc_md.cpu_die();
--
2.13.6