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| author | Andre Przywara <andre.przywara@linaro.org> | 2013-09-19 18:06:40 +0200 |
|---|---|---|
| committer | Albert ARIBAUD <albert.u.boot@aribaud.net> | 2013-10-03 21:27:11 +0200 |
| commit | 45b940d6f9a9d4989452ea67480e299bfa51ee19 (patch) | |
| tree | 636e0c5d2d8b7bfce8b7927e56044e0b95862806 | |
| parent | d75ba503a972df09784f1a332ba356ef8b42a0a6 (diff) | |
| download | u-boot-imx-45b940d6f9a9d4989452ea67480e299bfa51ee19.zip u-boot-imx-45b940d6f9a9d4989452ea67480e299bfa51ee19.tar.gz u-boot-imx-45b940d6f9a9d4989452ea67480e299bfa51ee19.tar.bz2 | |
ARM: add secure monitor handler to switch to non-secure state
A prerequisite for using virtualization is to be in HYP mode, which
requires the CPU to be in non-secure state first.
Add a new file in arch/arm/cpu/armv7 to hold a monitor handler routine
which switches the CPU to non-secure state by setting the NS and
associated bits.
According to the ARM architecture reference manual this should not be
done in SVC mode, so we have to setup a SMC handler for this.
We create a new vector table to avoid interference with other boards.
The MVBAR register will be programmed later just before the smc call.
Signed-off-by: Andre Przywara <andre.przywara@linaro.org>
| -rw-r--r-- | arch/arm/cpu/armv7/Makefile | 4 | ||||
| -rw-r--r-- | arch/arm/cpu/armv7/nonsec_virt.S | 53 |
2 files changed, 57 insertions, 0 deletions
diff --git a/arch/arm/cpu/armv7/Makefile b/arch/arm/cpu/armv7/Makefile index b723e22..3466c7a 100644 --- a/arch/arm/cpu/armv7/Makefile +++ b/arch/arm/cpu/armv7/Makefile @@ -20,6 +20,10 @@ ifneq ($(CONFIG_AM43XX)$(CONFIG_AM33XX)$(CONFIG_OMAP44XX)$(CONFIG_OMAP54XX)$(CON SOBJS += lowlevel_init.o endif +ifneq ($(CONFIG_ARMV7_NONSEC),) +SOBJS += nonsec_virt.o +endif + SRCS := $(START:.o=.S) $(COBJS:.o=.c) OBJS := $(addprefix $(obj),$(COBJS) $(SOBJS)) START := $(addprefix $(obj),$(START)) diff --git a/arch/arm/cpu/armv7/nonsec_virt.S b/arch/arm/cpu/armv7/nonsec_virt.S new file mode 100644 index 0000000..d11eb2d --- /dev/null +++ b/arch/arm/cpu/armv7/nonsec_virt.S @@ -0,0 +1,53 @@ +/* + * code for switching cores into non-secure state + * + * Copyright (c) 2013 Andre Przywara <andre.przywara@linaro.org> + * + * See file CREDITS for list of people who contributed to this + * project. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of + * the License, or (at your option) any later version. + * + * 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 <config.h> + +/* the vector table for secure state */ +_monitor_vectors: + .word 0 /* reset */ + .word 0 /* undef */ + adr pc, _secure_monitor + .word 0 + .word 0 + .word 0 + .word 0 + .word 0 + +/* + * secure monitor handler + * U-boot calls this "software interrupt" in start.S + * This is executed on a "smc" instruction, we use a "smc #0" to switch + * to non-secure state. + * We use only r0 and r1 here, due to constraints in the caller. + */ + .align 5 +_secure_monitor: + mrc p15, 0, r1, c1, c1, 0 @ read SCR + bic r1, r1, #0x4e @ clear IRQ, FIQ, EA, nET bits + orr r1, r1, #0x31 @ enable NS, AW, FW bits + + mcr p15, 0, r1, c1, c1, 0 @ write SCR (with NS bit set) + + movs pc, lr @ return to non-secure SVC |