Catalin Marinas | d7f864b | 2008-04-18 22:43:06 +0100 | [diff] [blame] | 1 | /* |
| 2 | * arch/arm/kernel/thumbee.c |
| 3 | * |
| 4 | * Copyright (C) 2008 ARM Limited |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License version 2 as |
| 8 | * published by the Free Software Foundation. |
| 9 | * |
| 10 | * This program is distributed in the hope that it will be useful, |
| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 13 | * GNU General Public License for more details. |
| 14 | * |
| 15 | * You should have received a copy of the GNU General Public License |
| 16 | * along with this program; if not, write to the Free Software |
| 17 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| 18 | */ |
| 19 | |
| 20 | #include <linux/kernel.h> |
| 21 | #include <linux/init.h> |
| 22 | |
| 23 | #include <asm/thread_notify.h> |
| 24 | |
| 25 | /* |
| 26 | * Access to the ThumbEE Handler Base register |
| 27 | */ |
| 28 | static inline unsigned long teehbr_read() |
| 29 | { |
| 30 | unsigned long v; |
| 31 | asm("mrc p14, 6, %0, c1, c0, 0\n" : "=r" (v)); |
| 32 | return v; |
| 33 | } |
| 34 | |
| 35 | static inline void teehbr_write(unsigned long v) |
| 36 | { |
| 37 | asm("mcr p14, 6, %0, c1, c0, 0\n" : : "r" (v)); |
| 38 | } |
| 39 | |
| 40 | static int thumbee_notifier(struct notifier_block *self, unsigned long cmd, void *t) |
| 41 | { |
| 42 | struct thread_info *thread = t; |
| 43 | |
| 44 | switch (cmd) { |
| 45 | case THREAD_NOTIFY_FLUSH: |
| 46 | thread->thumbee_state = 0; |
| 47 | break; |
| 48 | case THREAD_NOTIFY_SWITCH: |
| 49 | current_thread_info()->thumbee_state = teehbr_read(); |
| 50 | teehbr_write(thread->thumbee_state); |
| 51 | break; |
| 52 | } |
| 53 | |
| 54 | return NOTIFY_DONE; |
| 55 | } |
| 56 | |
| 57 | static struct notifier_block thumbee_notifier_block = { |
| 58 | .notifier_call = thumbee_notifier, |
| 59 | }; |
| 60 | |
| 61 | static int __init thumbee_init(void) |
| 62 | { |
| 63 | unsigned long pfr0; |
| 64 | unsigned int cpu_arch = cpu_architecture(); |
| 65 | |
| 66 | if (cpu_arch < CPU_ARCH_ARMv7) |
| 67 | return 0; |
| 68 | |
| 69 | /* processor feature register 0 */ |
| 70 | asm("mrc p15, 0, %0, c0, c1, 0\n" : "=r" (pfr0)); |
| 71 | if ((pfr0 & 0x0000f000) != 0x00001000) |
| 72 | return 0; |
| 73 | |
| 74 | printk(KERN_INFO "ThumbEE CPU extension supported.\n"); |
| 75 | elf_hwcap |= HWCAP_THUMBEE; |
| 76 | thread_register_notifier(&thumbee_notifier_block); |
| 77 | |
| 78 | return 0; |
| 79 | } |
| 80 | |
| 81 | late_initcall(thumbee_init); |