Hi Oleksandr, On Fri, May 3, 2019 at 1:21 PM Oleksandr Tyshchenko <olekstysh@xxxxxxxxx> wrote: > From: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx> > > If PSCI is available then most likely we are running on PSCI-enabled > U-Boot which, we assume, has already taken care of resetting CNTVOFF > before switching to non-secure mode and we don't need to. > > Also, don't init CNTVOFF if we are running on top of Xen hypervisor, > as CNTVOFF is controlled by hypervisor itself and shouldn't be touched > by Dom0 in such case. > > Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx> > CC: Julien Grall <julien.grall@xxxxxxx> Thanks for your patch! > --- > You can find previous discussion here: > https://lkml.org/lkml/2019/4/17/810 > > Changes in v2: > - Clarify patch subject/description > - Don't use CONFIG_ARM_PSCI option, check whether the PSCI is available, > by using psci_smp_available() > - Check whether we are running on top of Xen, by using xen_domain() > --- > arch/arm/mach-shmobile/setup-rcar-gen2.c | 13 ++++++++++++- > 1 file changed, 12 insertions(+), 1 deletion(-) > > diff --git a/arch/arm/mach-shmobile/setup-rcar-gen2.c b/arch/arm/mach-shmobile/setup-rcar-gen2.c > index eea60b2..bc8537b 100644 > --- a/arch/arm/mach-shmobile/setup-rcar-gen2.c > +++ b/arch/arm/mach-shmobile/setup-rcar-gen2.c > @@ -17,7 +17,9 @@ > #include <linux/of.h> > #include <linux/of_fdt.h> > #include <linux/of_platform.h> > +#include <xen/xen.h> > #include <asm/mach/arch.h> > +#include <asm/psci.h> > #include <asm/secure_cntvoff.h> > #include "common.h" > #include "rcar-gen2.h" > @@ -63,7 +65,16 @@ void __init rcar_gen2_timer_init(void) > void __iomem *base; > u32 freq; > > - secure_cntvoff_init(); > + /* > + * If PSCI is available then most likely we are running on PSCI-enabled > + * U-Boot which, we assume, has already taken care of resetting CNTVOFF > + * before switching to non-secure mode and we don't need to. > + * Another check is to be sure that we are not running on top of Xen > + * hypervisor, as CNTVOFF is controlled by hypervisor itself and > + * shouldn't be touched by Dom0 in such case. > + */ > + if (!psci_smp_available() && !xen_domain()) > + secure_cntvoff_init(); > > if (of_machine_is_compatible("renesas,r8a7745") || > of_machine_is_compatible("renesas,r8a77470") || How do you prevent secure_cntvoff_init() from being called for secondary CPUs in arch/arm/mach-shmobile/headsmp-apmu.S? With PSCI, it is not called if "enable-method" in DT is "psci"', so that case is covered, I guess. What about XEN? Do you override the "enable-method"? If yes, perhaps a check for "renesas,apmu" is more appropriate? Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
