Re: [AArch64 boot-wrapper][PATCH] aarch64: Enable FGT for EL2
From: Andre Przywara <andre.przywara@arm.com>
Date: 2021-05-04 15:22:08
On Mon, 3 May 2021 13:09:20 +0100 Marc Zyngier [off-list ref] 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@kernel.org>
Verified the bits used against the ARM ARM. Also Trusted Firmware does the same thing, so: Reviewed-by: Andre Przywara <andre.przywara@arm.com> Cheers, Andre
quoted hunk ↗ jump to hunk
--- 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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