/*
* arch/arm/kernel/thumbee.c
*
* Copyright (C) 2008 ARM Limited
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <asm/thread_notify.h>
/*
* Access to the ThumbEE Handler Base register
*/
static inline unsigned long teehbr_read(void)
{
unsigned long v;
asm("mrc p14, 6, %0, c1, c0, 0\n" : "=r" (v));
return v;
}
static inline void teehbr_write(unsigned long v)
{
asm("mcr p14, 6, %0, c1, c0, 0\n" : : "r" (v));
}
static int thumbee_notifier(struct notifier_block *self, unsigned long cmd, void *t)
{
struct thread_info *thread = t;
switch (cmd) {
case THREAD_NOTIFY_FLUSH:
thread->thumbee_state = 0;
break;
case THREAD_NOTIFY_SWITCH:
current_thread_info()->thumbee_state = teehbr_read();
teehbr_write(thread->thumbee_state);
break;
}
return NOTIFY_DONE;
}
static struct notifier_block thumbee_notifier_block = {
.notifier_call = thumbee_notifier,
};
static int __init thumbee_init(void)
{
unsigned long pfr0;
unsigned int cpu_arch = cpu_architecture();
if (cpu_arch < CPU_ARCH_ARMv7)
return 0;
/* processor feature register 0 */
asm("mrc p15, 0, %0, c0, c1, 0\n" : "=r" (pfr0));
if ((pfr0 & 0x0000f000) != 0x00001000)
return 0;
printk(KERN_INFO "ThumbEE CPU extension supported.\n");
elf_hwcap |= HWCAP_THUMBEE;
thread_register_notifier(&thumbee_notifier_block);
return 0;
}
late_initcall(thumbee_init);
