/* * 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() { 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);