Re: [PATCH 5/5] arm64: Document the requirement for SCR_EL3.HCE
From: Mark Rutland <mark.rutland@arm.com>
Date: 2021-08-24 10:52:10
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On Tue, Aug 24, 2021 at 11:49:01AM +0100, Catalin Marinas wrote:
On Thu, Aug 12, 2021 at 08:02:13PM +0100, Marc Zyngier wrote:quoted
It is amazing that we never documented this absolutely basic requirement: if you boot the kernel at EL2, you'd better enable the HVC instruction from EL3. Really, just do it. Signed-off-by: Marc Zyngier <maz@kernel.org> --- Documentation/arm64/booting.rst | 5 +++++ 1 file changed, 5 insertions(+)diff --git a/Documentation/arm64/booting.rst b/Documentation/arm64/booting.rst index a9192e7a231b..6c729d0c4bc2 100644 --- a/Documentation/arm64/booting.rst +++ b/Documentation/arm64/booting.rst@@ -212,6 +212,11 @@ Before jumping into the kernel, the following conditions must be met: - The value of SCR_EL3.FIQ must be the same as the one present at boot time whenever the kernel is executing. + For all systems: + - If EL3 is present and the kernel is entered at EL2: + + - SCR_EL3.HCE (bit 8) must be initialised to 0b1. + For systems with a GICv3 interrupt controller to be used in v3 mode: - If EL3 is present:I'll queue this patch only for now. A nitpick, I think we should move "For all systems" and "If EL3 is present..." above the lines describing the SCR_EL3.FIQ requirement (I can make the change locally).
FWIW, with that: Acked-by: Mark Rutland <mark.rutland@arm.com> Mark. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel