On Tue, Apr 10, 2018 at 12:53:32PM +0200, Lucas Stach wrote: > Am Donnerstag, den 05.04.2018, 09:54 +0200 schrieb Sascha Hauer: > > On Mon, Mar 26, 2018 at 09:20:19PM +0200, Lucas Stach wrote: > > > This adds routines to add hyp mode vectors and switch back to HYP > > > mode from SVC. This is needed in both the PBL and Barebox proper. > > > > > > > > Signed-off-by: Lucas Stach <l.stach@xxxxxxxxxxxxxx> > > > > > Tested-by: Roland Hieber <r.hieber@xxxxxxxxxxxxxx> > > > --- > > > v3: > > > - fix whitespace > > > - use __BARE_INIT > > > --- > > > arch/arm/cpu/Makefile | 4 ++ > > > arch/arm/cpu/hyp.S | 116 ++++++++++++++++++++++++++++++++++++++++++ > > > arch/arm/cpu/sm_as.S | 11 ---- > > > arch/arm/include/asm/secure.h | 8 +++ > > > 4 files changed, 128 insertions(+), 11 deletions(-) > > > create mode 100644 arch/arm/cpu/hyp.S > > > > > > diff --git a/arch/arm/cpu/Makefile b/arch/arm/cpu/Makefile > > > index 13fe12c31f6f..f86dff975bb4 100644 > > > --- a/arch/arm/cpu/Makefile > > > +++ b/arch/arm/cpu/Makefile > > > @@ -9,6 +9,10 @@ obj-$(CONFIG_ARM_EXCEPTIONS) += exceptions.o > > > obj-$(CONFIG_MMU) += mmu.o mmu-early.o > > > pbl-$(CONFIG_MMU) += mmu-early.o > > > lwl-y += lowlevel.o > > > +obj-y += hyp.o > > > +AFLAGS_hyp.o :=-Wa,-march=armv7-a -Wa,-mcpu=all > > > +pbl-y += hyp.o > > > +AFLAGS_pbl-hyp.o :=-Wa,-march=armv7-a -Wa,-mcpu=all > > > endif > > > > > > obj-$(CONFIG_ARM_EXCEPTIONS) += interrupts.o > > > diff --git a/arch/arm/cpu/hyp.S b/arch/arm/cpu/hyp.S > > > new file mode 100644 > > > index 000000000000..1314b56eab25 > > > --- /dev/null > > > +++ b/arch/arm/cpu/hyp.S > > > @@ -0,0 +1,116 @@ > > > +#include <linux/linkage.h> > > > +#include <asm/system.h> > > > +#include <asm/opcodes-virt.h> > > > +#include <init.h> > > > + > > > +.arch_extension sec > > > +.arch_extension virt > > > + > > > +__BARE_INIT > > > + > > > +.data > > > > > + .align 2 > > > +ENTRY(__boot_cpu_mode) > > > > > + .long 0 > > > +.text > > > + > > > +ENTRY(__hyp_install) > > > > > > > + mrs r12, cpsr > > > > > > > + and r12, r12, #MODE_MASK > > > + > > > > > + @ Save the initial CPU state > > > > > > > + adr r0, .L__boot_cpu_mode_offset > > > > > > > + ldr r1, [r0] > > > + str r12, [r0, r1] > > > > Naa, this won't work. You save the cpsr value in __boot_cpu_mode, but > > this variable exists both in PBL and regular barebox, __hyp_install > > is called multiple times and cpsr is modified right after saving it. > > It does. ;) > > I guess its non-obvious from the code flow, but what we do is to drop > down to SVC in the PBL, then jump back to HYP before starting barebox > proper and the dropping down to SVC again on barebox entry. > All in all this is less-than-pretty, but IMHO it's the lesser evil than > trying to implement some communication channel from PBL to barebox > proper to pass information like this. > > So I guess this code needs some more comments... Yep ;) Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ barebox mailing list barebox@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/barebox
