On 14 May 2014 00:53, Sergey Fedorov <[email protected]> wrote:
> On 13.05.2014 20:15, Fabian Aggeler wrote:
> > arm_is_secure() function allows to determine CPU security state
> > if the CPU implements Security Extensions.
> >
> > Signed-off-by: Sergey Fedorov <[email protected]>
> > Signed-off-by: Fabian Aggeler <[email protected]>
> > ---
> > target-arm/cpu.h | 15 +++++++++++++++
> > 1 file changed, 15 insertions(+)
> >
> > diff --git a/target-arm/cpu.h b/target-arm/cpu.h
> > index a56d3d6..6ea0432 100644
> > --- a/target-arm/cpu.h
> > +++ b/target-arm/cpu.h
> > @@ -640,6 +640,21 @@ static inline int arm_feature(CPUARMState *env, int
> feature)
> > return (env->features & (1ULL << feature)) != 0;
> > }
> >
> > +/* Return true if the processor is in secure state */
> > +static inline bool arm_is_secure(CPUARMState *env)
> > +{
> > +#if !defined(CONFIG_USER_ONLY)
> > + if (arm_feature(env, ARM_FEATURE_SECURITY_EXTENSIONS)) {
>
> I think feature test can be safely avoided here. Without this feature
> that should be no way to switch to monitor mode and to access SCR register.
>
I agree with the feature check here. For correctness, we should only be
examining c1_scr if the security extension is enabled. This is consistent
with only registering the SCR register if the feature is enabled.
> > + return ((env->uncached_cpsr & CPSR_M) == ARM_CPU_MODE_MON) ||
> > + !(env->cp15.c1_scr & 1);
> > + } else {
> > + return false;
> > + }
> > +#else
> > + return false;
>
> That is a good question how to treat user emulation: secure or
> non-secure. Perhaps assuming user emulation in secure state may simplify
> code in the following patches.
> > +#endif
> > +}
> > +
> > /* Return true if the specified exception level is running in AArch64
> state. */
> > static inline bool arm_el_is_aa64(CPUARMState *env, int el)
> > {
>
> Thanks,
> Sergey.
>
>
