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author | Catalin Marinas <catalin.marinas@arm.com> | 2008-04-18 22:43:06 +0100 |
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committer | Catalin Marinas <catalin.marinas@arm.com> | 2008-04-18 22:43:06 +0100 |
commit | d7f864be8323e5394040e2877594645b0e7da85d (patch) | |
tree | 55ecf960706be9a4ee0c7804c57c7f5d30e0f1f7 /arch/arm/kernel/thumbee.c | |
parent | 05dda977f2574c3341abef9b74c27d2b362e1e3a (diff) | |
download | op-kernel-dev-d7f864be8323e5394040e2877594645b0e7da85d.zip op-kernel-dev-d7f864be8323e5394040e2877594645b0e7da85d.tar.gz |
ARMv7: Add support for the ThumbEE state saving/restoring
This patch adds the detection and handling of the ThumbEE extension on
ARMv7 CPUs.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm/kernel/thumbee.c')
-rw-r--r-- | arch/arm/kernel/thumbee.c | 81 |
1 files changed, 81 insertions, 0 deletions
diff --git a/arch/arm/kernel/thumbee.c b/arch/arm/kernel/thumbee.c new file mode 100644 index 0000000..df3f6b7 --- /dev/null +++ b/arch/arm/kernel/thumbee.c @@ -0,0 +1,81 @@ +/* + * 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); |