linux-kernel - [PATCH v3 04/15] arm: Don't use disable_nonboot

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Message-Id: <20200223192942.18420-5-qais.yousef@arm.com>
Date:   Sun, 23 Feb 2020 19:29:31 +0000
From:   Qais Yousef <qais.yousef@....com>
To:     Thomas Gleixner <tglx@...utronix.de>
Cc:     "Paul E . McKenney" <paulmck@...nel.org>,
        Qais Yousef <qais.yousef@....com>,
        Russell King <linux@...linux.org.uk>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [PATCH v3 04/15] arm: Don't use disable_nonboot_cpus()

disable_nonboot_cpus() is not safe to use when doing machine_down(),
because it relies on freeze_secondary_cpus() which in turn is
a suspend/resume related freeze and could abort if the logic detects any
pending activities that can prevent finishing the offlining process.

Beside disable_nonboot_cpus() is dependent on CONFIG_PM_SLEEP_SMP which
is an othogonal config to rely on to ensure this function works
correctly.

Use `reboot_cpu` variable instead of hardcoding 0 as the reboot cpu.

Signed-off-by: Qais Yousef <qais.yousef@....com>
CC: Russell King <linux@...linux.org.uk>
CC: linux-arm-kernel@...ts.infradead.org
CC: linux-kernel@...r.kernel.org
---
 arch/arm/kernel/reboot.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm/kernel/reboot.c b/arch/arm/kernel/reboot.c
index bb18ed0539f4..0ce388f15422 100644
--- a/arch/arm/kernel/reboot.c
+++ b/arch/arm/kernel/reboot.c
@@ -88,11 +88,11 @@ void soft_restart(unsigned long addr)
  * to execute e.g. a RAM-based pin loop is not sufficient. This allows the
  * kexec'd kernel to use any and all RAM as it sees fit, without having to
  * avoid any code or data used by any SW CPU pin loop. The CPU hotplug
- * functionality embodied in disable_nonboot_cpus() to achieve this.
+ * functionality embodied in smp_shutdown_nonboot_cpus() to achieve this.
  */
 void machine_shutdown(void)
 {
-	disable_nonboot_cpus();
+	smp_shutdown_nonboot_cpus(reboot_cpu);
 }
 
 /*
-- 
2.17.1