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Commit 90b44199 authored by Russell King's avatar Russell King
Browse files

ARM: VFP: re-initialize VFP coprocessor access enables on CPU hotplug 



We can not guarantee that VFP will be enabled when CPU hotplug brings
a CPU back online from a reset state.  Add a hotplug CPU notifier to
ensure that the VFP coprocessor access is enabled whenever a CPU comes
back online.

Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent 3705ff6d

arch/arm/vfp/vfpmodule.c

+23 −1
Original line number Diff line number Diff line
@@ -10,9 +10,12 @@ 
 */

#include <linux/module.h>

#include <linux/types.h>

#include <linux/cpu.h>

#include <linux/kernel.h>

#include <linux/notifier.h>

#include <linux/signal.h>

#include <linux/sched.h>

#include <linux/smp.h>

#include <linux/init.h>



#include <asm/cputype.h>
@@ -484,7 +487,24 @@ void vfp_flush_hwstate(struct thread_info *thread) 
	put_cpu();

}



#include <linux/smp.h>

/*

 * VFP hardware can lose all context when a CPU goes offline.

 * Safely clear our held state when a CPU has been killed, and

 * re-enable access to VFP when the CPU comes back online.

 *

 * Both CPU_DYING and CPU_STARTING are called on the CPU which

 * is being offlined/onlined.

 */

static int vfp_hotplug(struct notifier_block *b, unsigned long action,

	void *hcpu)

{

	if (action == CPU_DYING || action == CPU_DYING_FROZEN) {

		unsigned int cpu = (long)hcpu;

		last_VFP_context[cpu] = NULL;

	} else if (action == CPU_STARTING || action == CPU_STARTING_FROZEN)

		vfp_enable(NULL);

	return NOTIFY_OK;

}



/*

 * VFP support code initialisation.
@@ -514,6 +534,8 @@ static int __init vfp_init(void) 
	else if (vfpsid & FPSID_NODOUBLE) {

		printk("no double precision support\n");

	} else {

		hotcpu_notifier(vfp_hotplug, 0);



		smp_call_function(vfp_enable, NULL, 1);



		VFP_arch = (vfpsid & FPSID_ARCH_MASK) >> FPSID_ARCH_BIT;  /* Extract the architecture version */