[AArch64 boot-wrapper][PATCH] aarch64: Enable FGT for EL2
Andre Przywara
andre.przywara at arm.com
Tue May 4 08:19:12 PDT 2021
On Mon, 3 May 2021 13:09:20 +0100
Marc Zyngier <maz at kernel.org> wrote:
> We have no intention of handling FGT traps to EL3, so let EL2
> play with the feature directly.
>
> Signed-off-by: Marc Zyngier <maz at kernel.org>
Verified the bits used against the ARM ARM. Also Trusted Firmware does
the same thing, so:
Reviewed-by: Andre Przywara <andre.przywara at arm.com>
Cheers,
Andre
> ---
>
> Notes:
> Needed to boot Linux 5.13 at EL2.
>
> arch/aarch64/boot.S | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/arch/aarch64/boot.S b/arch/aarch64/boot.S
> index e47cf59..fd7133d 100644
> --- a/arch/aarch64/boot.S
> +++ b/arch/aarch64/boot.S
> @@ -54,6 +54,13 @@ _start:
> cbz x1, 1f
>
> orr x0, x0, #(1 << 34) // TME enable
> +1:
> + /* Enable FGT if present */
> + mrs x1, id_aa64mmfr0_el1
> + ubfx x1, x1, #56, #4
> + cbz x1, 1f
> +
> + orr x0, x0, #(1 << 27) // FGT enable
> 1:
> #ifndef KERNEL_32
> orr x0, x0, #(1 << 10) // 64-bit EL2
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