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>
diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
index 00d44c6..d5be3f7 100644
--- a/arch/arm/kernel/Makefile
+++ b/arch/arm/kernel/Makefile
@@ -22,6 +22,7 @@
obj-$(CONFIG_KPROBES) += kprobes.o kprobes-decode.o
obj-$(CONFIG_ATAGS_PROC) += atags.o
obj-$(CONFIG_OABI_COMPAT) += sys_oabi-compat.o
+obj-$(CONFIG_ARM_THUMBEE) += thumbee.o
obj-$(CONFIG_CRUNCH) += crunch.o crunch-bits.o
AFLAGS_crunch-bits.o := -Wa,-mcpu=ep9312
diff --git a/arch/arm/kernel/asm-offsets.c b/arch/arm/kernel/asm-offsets.c
index 3278e71..6604b47 100644
--- a/arch/arm/kernel/asm-offsets.c
+++ b/arch/arm/kernel/asm-offsets.c
@@ -58,6 +58,9 @@
DEFINE(TI_TP_VALUE, offsetof(struct thread_info, tp_value));
DEFINE(TI_FPSTATE, offsetof(struct thread_info, fpstate));
DEFINE(TI_VFPSTATE, offsetof(struct thread_info, vfpstate));
+#ifdef CONFIG_ARM_THUMBEE
+ DEFINE(TI_THUMBEE_STATE, offsetof(struct thread_info, thumbee_state));
+#endif
#ifdef CONFIG_IWMMXT
DEFINE(TI_IWMMXT_STATE, offsetof(struct thread_info, fpstate.iwmmxt));
#endif
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);
diff --git a/arch/arm/mm/Kconfig b/arch/arm/mm/Kconfig
index 76348f0..084fe8d 100644
--- a/arch/arm/mm/Kconfig
+++ b/arch/arm/mm/Kconfig
@@ -572,6 +572,13 @@
If you don't know what this all is, saying Y is a safe choice.
+config ARM_THUMBEE
+ bool "Enable ThumbEE CPU extension"
+ depends on CPU_V7
+ help
+ Say Y here if you have a CPU with the ThumbEE extension and code to
+ make use of it. Say N for code that can run on CPUs without ThumbEE.
+
config CPU_BIG_ENDIAN
bool "Build big-endian kernel"
depends on ARCH_SUPPORTS_BIG_ENDIAN
diff --git a/include/asm-arm/hwcap.h b/include/asm-arm/hwcap.h
index 01a1391..81f4c89 100644
--- a/include/asm-arm/hwcap.h
+++ b/include/asm-arm/hwcap.h
@@ -15,6 +15,7 @@
#define HWCAP_JAVA 256
#define HWCAP_IWMMXT 512
#define HWCAP_CRUNCH 1024
+#define HWCAP_THUMBEE 2048
#if defined(__KERNEL__) && !defined(__ASSEMBLY__)
/*
diff --git a/include/asm-arm/thread_info.h b/include/asm-arm/thread_info.h
index 4178435..f5a6647 100644
--- a/include/asm-arm/thread_info.h
+++ b/include/asm-arm/thread_info.h
@@ -62,6 +62,9 @@
struct crunch_state crunchstate;
union fp_state fpstate __attribute__((aligned(8)));
union vfp_state vfpstate;
+#ifdef CONFIG_ARM_THUMBEE
+ unsigned long thumbee_state; /* ThumbEE Handler Base register */
+#endif
struct restart_block restart_block;
};