Messages in this thread | | | Date | Tue, 24 Aug 2021 11:49:01 +0100 | From | Catalin Marinas <> | Subject | Re: [PATCH 5/5] arm64: Document the requirement for SCR_EL3.HCE |
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On Thu, Aug 12, 2021 at 08:02:13PM +0100, Marc Zyngier wrote: > 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).
-- Catalin
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