| Message ID | 1376060592-10824-3-git-send-email-andre.przywara@linaro.org |
|---|---|
| State | Changes Requested |
| Delegated to: | Albert ARIBAUD |
| Headers | show |
Hello Andre, > +/* 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 > + .word 0 /* pad */ Could you explain why the last line is needed? Best Regards Masahiro Yamada
On 08/27/2013 02:23 AM, Masahiro Yamada wrote: > Hello Andre, > >> +/* 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 >> + .word 0 /* pad */ > > Could you explain why the last line is needed? I guess I cannot explain because it's probably not needed ;-) I copied this from somewhere else and accidentally this padding somehow sneaked in (from the actual addresses array, where the start vector was missing and thus the array ended at 7 * 4 bytes) Do we need another version or is a follow-up patch sufficient? I'd like to avoid another review round for the sake of the reviewers. Thanks for spotting this, Andre.
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 08/27/2013 05:51 AM, Andre Przywara wrote: > On 08/27/2013 02:23 AM, Masahiro Yamada wrote: >> Hello Andre, >> >>> +/* 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 + .word 0 /* pad */ >> >> Could you explain why the last line is needed? > > I guess I cannot explain because it's probably not needed ;-) I > copied this from somewhere else and accidentally this padding > somehow sneaked in (from the actual addresses array, where the > start vector was missing and thus the array ended at 7 * 4 bytes) > > Do we need another version or is a follow-up patch sufficient? I'd > like to avoid another review round for the sake of the reviewers. Lets do a follow-up and Albert can squash it if desired. - -- Tom -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQIcBAEBAgAGBQJSHJdtAAoJENk4IS6UOR1WDgcP/1Rz+1U/La9brudy9OyjeVqT FYdWMtFr/TGELkoaUX/saY/MZoIPBpCO4iW8y5UvQJ3cQAm5WqgPK4/ku3wcbYC6 yaVC91fQ9UQEqzmUBCRGZAGwJuZ+JiElP/9wmqEi7RvnQTYimRYkEpm+XgxRkuX0 l3HH5QLyTO8CbQ4FKm8XeE0JeMfpNqPflMo5oDNMVlWC7a4VXMP49uIGoYt6emPp d7US4neOZRgL0ANiC/WoV807otl+llFRgZ0zqM7A60th+jJ2YqJIyZlp6QnL2r+Z YDLlKSvwBliYlmdFWFxxfUoe+4qK27HrOA39PP/Cj5ocQCoEzIRZFTXhlV3AeB9L CEhXgImSs0BS4AxN7CPdaJLdDGalphthkHOuGP66m+Xb9k7v6gmdNhphusX01FhC UUgRRKVUT02dS+51tMRxk1wdy805eI6zo34hmvS2SmWWuxAM1kCQhphUl+Ib1ew6 H7V+XoDdOp+iQzABB86TL8J8KtoUgiVA81NqQsvbiW4pR5rUoxBhTTXEYOnZyMYA qypDCyYepuQCLtz5kxxe0b1Y4tmZsNKtnVuMA55LtPVLHqX1uJ/vXXHBTsO3rGG3 Rz3BTq0o9GVYBg6YLJh496qD8kzqOfnhpu3U+5Fc10H0ldlDcs8YhLU+hzVD+nLD dDuxa9OzgPsEK/Wc1mWg =5MkM -----END PGP SIGNATURE-----
diff --git a/arch/arm/cpu/armv7/Makefile b/arch/arm/cpu/armv7/Makefile index 7a8c2d0..11a8ad5 100644 --- a/arch/arm/cpu/armv7/Makefile +++ b/arch/arm/cpu/armv7/Makefile @@ -36,6 +36,10 @@ ifneq ($(CONFIG_AM33XX)$(CONFIG_OMAP44XX)$(CONFIG_OMAP54XX)$(CONFIG_TEGRA)$(CONF SOBJS += lowlevel_init.o endif +ifneq ($(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..dbe5c0f --- /dev/null +++ b/arch/arm/cpu/armv7/nonsec_virt.S @@ -0,0 +1,55 @@ +/* + * 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 + .word 0 /* pad */ + +/* + * 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 +
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> --- arch/arm/cpu/armv7/Makefile | 4 +++ arch/arm/cpu/armv7/nonsec_virt.S | 55 ++++++++++++++++++++++++++++++++++++++++ 2 files changed, 59 insertions(+) create mode 100644 arch/arm/cpu/armv7/nonsec_virt.S