On Mon, Jan 25, 2016 at 03:53:35PM +0000, Marc Zyngier wrote:
> With ARMv8.1 VHE extension, it will be possible to run the kernel
> at EL2 (aka HYP mode). In order for the kernel to easily find out
> where it is running, add a new predicate that returns whether or
> not the kernel is in HYP mode.
>
> For completeness, the 32bit code also get such a predicate (always
> returning false) so that code common to both architecture (timers,
> KVM) can use it transparently.
>
> Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Acked-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
> ---
> arch/arm/include/asm/virt.h | 5 +++++
> arch/arm64/include/asm/virt.h | 10 ++++++++++
> 2 files changed, 15 insertions(+)
>
> diff --git a/arch/arm/include/asm/virt.h b/arch/arm/include/asm/virt.h
> index 4371f45..b6a3cef 100644
> --- a/arch/arm/include/asm/virt.h
> +++ b/arch/arm/include/asm/virt.h
> @@ -74,6 +74,11 @@ static inline bool is_hyp_mode_mismatched(void)
> {
> return !!(__boot_cpu_mode & BOOT_CPU_MODE_MISMATCH);
> }
> +
> +static inline bool is_kernel_in_hyp_mode(void)
> +{
> + return false;
> +}
> #endif
>
> #endif /* __ASSEMBLY__ */
> diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h
> index 7a5df52..9f22dd6 100644
> --- a/arch/arm64/include/asm/virt.h
> +++ b/arch/arm64/include/asm/virt.h
> @@ -23,6 +23,8 @@
>
> #ifndef __ASSEMBLY__
>
> +#include <asm/ptrace.h>
> +
> /*
> * __boot_cpu_mode records what mode CPUs were booted in.
> * A correctly-implemented bootloader must start all CPUs in the same mode:
> @@ -50,6 +52,14 @@ static inline bool is_hyp_mode_mismatched(void)
> return __boot_cpu_mode[0] != __boot_cpu_mode[1];
> }
>
> +static inline bool is_kernel_in_hyp_mode(void)
> +{
> + u64 el;
> +
> + asm("mrs %0, CurrentEL" : "=r" (el));
> + return el == CurrentEL_EL2;
> +}
> +
> /* The section containing the hypervisor text */
> extern char __hyp_text_start[];
> extern char __hyp_text_end[];
> --
> 2.1.4
>
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