From: Florian Fainelli <f.fainelli@gmail.com>
To: linux-arm-kernel@lists.infradead.org
Cc: Florian Fainelli <f.fainelli@gmail.com>,
Russell King <linux@armlinux.org.uk>,
bcm-kernel-feedback-list@broadcom.com (maintainer:BROADCOM
BCM7XXX ARM ARCHITECTURE),
Jonathan Austin <jonathan.austin@arm.com>,
Vladimir Murzin <vladimir.murzin@arm.com>,
Thomas Gleixner <tglx@linutronix.de>,
Zhaoxiu Zeng <zhaoxiu.zeng@gmail.com>,
Mark Rutland <mark.rutland@arm.com>,
Nicolas Pitre <nico@linaro.org>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Anna-Maria Gleixner <anna-maria@linutronix.de>,
linux-kernel@vger.kernel.org (open list),
will.deacon@arm.com
Subject: [PATCH 6/7] ARM: B15: Register reboot notifier for KEXEC
Date: Wed, 18 Jan 2017 12:29:25 -0800 [thread overview]
Message-ID: <20170118202927.28740-7-f.fainelli@gmail.com> (raw)
In-Reply-To: <20170118202927.28740-1-f.fainelli@gmail.com>
During kexec, we will go through kernel_kexec() -> syscore_suspend() if
CONFIG_KEXEC_JUMP is set, if not, down the road we end-up calling
kernel_restart_prepare() which invokes reboot notifiers with
SYS_RESTART.
We register a reboot notifier to make sure that the B15 read-ahead cache
is disabled, since it is another level of instruction and data cache,
and we want to avoid any potential side effects with booting a new
kernel with such a cache still turned on.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
---
arch/arm/mm/cache-b15-rac.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 44 insertions(+)
diff --git a/arch/arm/mm/cache-b15-rac.c b/arch/arm/mm/cache-b15-rac.c
index ef5e93e4b5c2..148d51fdfc3d 100644
--- a/arch/arm/mm/cache-b15-rac.c
+++ b/arch/arm/mm/cache-b15-rac.c
@@ -16,6 +16,7 @@
#include <linux/notifier.h>
#include <linux/cpu.h>
#include <linux/syscore_ops.h>
+#include <linux/reboot.h>
#include <asm/cacheflush.h>
#include <asm/hardware/cache-b15-rac.h>
@@ -151,6 +152,29 @@ static void b15_rac_enable(void)
__b15_rac_enable(enable);
}
+static int b15_rac_reboot_notifier(struct notifier_block *nb,
+ unsigned long action,
+ void *data)
+{
+ /* During kexec, we are not yet migrated on the boot CPU, so we need to
+ * make sure we are SMP safe here. Once the RAC is disabled, flag it as
+ * suspended such that the hotplug notifier returns early.
+ */
+ if (action == SYS_RESTART) {
+ spin_lock(&rac_lock);
+ b15_rac_disable_and_flush();
+ clear_bit(RAC_ENABLED, &b15_rac_flags);
+ set_bit(RAC_SUSPENDED, &b15_rac_flags);
+ spin_unlock(&rac_lock);
+ }
+
+ return NOTIFY_DONE;
+}
+
+static struct notifier_block b15_rac_reboot_nb = {
+ .notifier_call = b15_rac_reboot_notifier,
+};
+
#ifdef CONFIG_HOTPLUG_CPU
/* The CPU hotplug case is the most interesting one, we basically need to make
* sure that the RAC is disabled for the entire system prior to having a CPU
@@ -191,6 +215,12 @@ static void b15_rac_enable(void)
/* Running on the dying CPU */
static int b15_rac_dying_cpu(unsigned int cpu)
{
+ /* During kexec/reboot, the RAC is disabled via the reboot notifier
+ * return early here.
+ */
+ if (test_bit(RAC_SUSPENDED, &b15_rac_flags))
+ return 0;
+
spin_lock(&rac_lock);
/* Indicate that we are starting a hotplug procedure */
@@ -207,6 +237,12 @@ static int b15_rac_dying_cpu(unsigned int cpu)
/* Running on a non-dying CPU */
static int b15_rac_dead_cpu(unsigned int cpu)
{
+ /* During kexec/reboot, the RAC is disabled via the reboot notifier
+ * return early here.
+ */
+ if (test_bit(RAC_SUSPENDED, &b15_rac_flags))
+ return 0;
+
spin_lock(&rac_lock);
/* And enable it */
@@ -272,6 +308,13 @@ static int __init b15_rac_init(void)
goto out;
}
+ ret = register_reboot_notifier(&b15_rac_reboot_nb);
+ if (ret) {
+ pr_err("failed to register reboot notifier\n");
+ iounmap(b15_rac_base);
+ goto out;
+ }
+
#ifdef CONFIG_HOTPLUG_CPU
ret = cpuhp_setup_state_nocalls(CPUHP_AP_ARM_CACHE_B15_RAC_DEAD,
"arm/cache-b15-rac:dead",
@@ -308,6 +351,7 @@ static int __init b15_rac_init(void)
out_cpu_dead:
cpuhp_remove_state_nocalls(CPUHP_AP_ARM_CACHE_B15_RAC_DYING);
out_unmap:
+ unregister_reboot_notifier(&b15_rac_reboot_nb);
iounmap(b15_rac_base);
out:
of_node_put(dn);
--
2.9.3
next prev parent reply other threads:[~2017-01-18 20:31 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-18 20:29 [PATCH 0/7] ARM: Broadcom Brahma-B15 readahead cache support Florian Fainelli
2017-01-18 20:29 ` [PATCH 1/7] ARM: v7: allow setting different cache functions Florian Fainelli
2017-01-18 20:29 ` [PATCH 2/7] ARM: Add Broadcom Brahma-B15 readahead cache support Florian Fainelli
2017-01-18 22:56 ` Russell King - ARM Linux
2017-01-19 0:18 ` Florian Fainelli
2017-01-18 20:29 ` [PATCH 3/7] ARM: Hook B15 readahead cache functions based on processor Florian Fainelli
2017-01-18 20:29 ` [PATCH 4/7] ARM: B15: Add CPU hotplug awareness Florian Fainelli
2017-01-18 20:29 ` [PATCH 5/7] ARM: B15: Add suspend/resume hooks Florian Fainelli
2017-01-18 20:29 ` Florian Fainelli [this message]
2017-01-18 20:29 ` [PATCH 7/7] MAINTAINERS: Update brcmstb entries to cover B15 code Florian Fainelli
2017-01-18 20:29 ` [PATCH 8/8] ARM: smp: Remove CPU: shutdown notice Florian Fainelli
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