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From: anna-maria@linutronix.de (Anna-Maria Gleixner)
To: linux-arm-kernel@lists.infradead.org
Subject: [patch V2 34/67] arm: Convert VFP hotplug notifiers to state machine
Date: Wed, 13 Jul 2016 17:16:35 -0000
Message-ID: <20160713153335.713612993@linutronix.de> (raw)
In-Reply-To: <20160713153219.128052238@linutronix.de>

From: Thomas Gleixner <tglx@linutronix.de>

Straight forward conversion plus commentary why code which is executed
in hotplug callbacks needs to be invoked before installing them.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: linux-arm-kernel at lists.infradead.org
Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
---
 arch/arm/vfp/vfpmodule.c   | 28 +++++++++++++++++-----------
 include/linux/cpuhotplug.h |  1 +
 2 files changed, 18 insertions(+), 11 deletions(-)

diff --git a/arch/arm/vfp/vfpmodule.c b/arch/arm/vfp/vfpmodule.c
index 73085d3..da0b33d 100644
--- a/arch/arm/vfp/vfpmodule.c
+++ b/arch/arm/vfp/vfpmodule.c
@@ -643,19 +643,19 @@ int vfp_restore_user_hwstate(struct user_vfp __user *ufp,
  * hardware state at every thread switch.  We clear our held state when
  * a CPU has been killed, indicating that the VFP hardware doesn't contain
  * a threads VFP state.  When a CPU starts up, we re-enable access to the
- * VFP hardware.
- *
- * Both CPU_DYING and CPU_STARTING are called on the CPU which
+ * VFP hardware. The callbacks below are called on the CPU which
  * is being offlined/onlined.
  */
-static int vfp_hotplug(struct notifier_block *b, unsigned long action,
-	void *hcpu)
+static int vfp_dying_cpu(unsigned int cpu)
 {
-	if (action == CPU_DYING || action == CPU_DYING_FROZEN)
-		vfp_current_hw_state[(long)hcpu] = NULL;
-	else if (action == CPU_STARTING || action == CPU_STARTING_FROZEN)
-		vfp_enable(NULL);
-	return NOTIFY_OK;
+	vfp_force_reload(cpu, current_thread_info());
+	return 0;
+}
+
+static int vfp_starting_cpu(unsigned int unused)
+{
+	vfp_enable(NULL);
+	return 0;
 }
 
 void vfp_kmode_exception(void)
@@ -732,6 +732,10 @@ static int __init vfp_init(void)
 	unsigned int vfpsid;
 	unsigned int cpu_arch = cpu_architecture();
 
+	/*
+	 * Enable the access to the VFP on all online CPUs so the
+	 * following test on FPSID will succeed.
+	 */
 	if (cpu_arch >= CPU_ARCH_ARMv6)
 		on_each_cpu(vfp_enable, NULL, 1);
 
@@ -794,7 +798,9 @@ static int __init vfp_init(void)
 		VFP_arch = (vfpsid & FPSID_ARCH_MASK) >> FPSID_ARCH_BIT;
 	}
 
-	hotcpu_notifier(vfp_hotplug, 0);
+	cpuhp_setup_state_nocalls(CPUHP_AP_ARM_VFP_STARTING,
+				  "AP_ARM_VFP_STARTING", vfp_starting_cpu,
+				  vfp_dying_cpu);
 
 	vfp_vector = vfp_support_entry;
 
diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index e8d1b84..2e227b6 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -35,6 +35,7 @@ enum cpuhp_state {
 	CPUHP_AP_PERF_X86_CQM_STARTING,
 	CPUHP_AP_PERF_X86_CSTATE_STARTING,
 	CPUHP_AP_PERF_XTENSA_STARTING,
+	CPUHP_AP_ARM_VFP_STARTING,
 	CPUHP_AP_NOTIFY_STARTING,
 	CPUHP_AP_ONLINE,
 	CPUHP_TEARDOWN_CPU,
-- 
2.8.1

  parent reply index

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20160713153219.128052238@linutronix.de>
2016-07-13 17:16 ` [patch V2 08/67] ARM: mvebu: Convert to hotplug " Anna-Maria Gleixner
2016-07-13 17:16 ` Anna-Maria Gleixner [this message]
2016-07-13 17:16 ` [patch V2 44/67] arm/kvm/vgic: " Anna-Maria Gleixner
2016-07-13 17:16 ` [patch V2 45/67] arm/kvm/arch_timer: " Anna-Maria Gleixner
2016-07-13 17:16 ` [patch V2 47/67] arm/l2c: " Anna-Maria Gleixner
2016-07-13 17:16 ` [patch V2 48/67] arm/twd: " Anna-Maria Gleixner
2016-07-13 17:16 ` [patch V2 49/67] arm/xen: " Anna-Maria Gleixner
2016-07-13 18:21   ` Stefano Stabellini
2016-07-13 17:16 ` [patch V2 51/67] hwtracing/coresight-etm3x: " Anna-Maria Gleixner
2016-07-13 17:16 ` [patch V2 52/67] hwtracing/coresight-etm4x: " Anna-Maria Gleixner
2016-07-13 17:16 ` [patch V2 53/67] arm64/armv8 deprecated: " Anna-Maria Gleixner
2016-07-13 17:17 ` [patch V2 60/67] KVM/arm/arm64/vgic-new: " Anna-Maria Gleixner
2016-07-14 13:08   ` Marc Zyngier
2016-07-13 17:17 ` [patch V2 62/67] [PATCH] clocksource: arm_global_timer: " Anna-Maria Gleixner

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