From 71dcb8be6d29cffff3f4a4463232f38786e97797 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Tue, 27 Feb 2018 17:38:08 +0000 Subject: arm64: KVM: Allow far branches from vector slots to the main vectors So far, the branch from the vector slots to the main vectors can at most be 4GB from the main vectors (the reach of ADRP), and this distance is known at compile time. If we were to remap the slots to an unrelated VA, things would break badly. A way to achieve VA independence would be to load the absolute address of the vectors (__kvm_hyp_vector), either using a constant pool or a series of movs, followed by an indirect branch. This patches implements the latter solution, using another instance of a patching callback. Note that since we have to save a register pair on the stack, we branch to the *second* instruction in the vectors in order to compensate for it. This also results in having to adjust this balance in the invalid vector entry point. Acked-by: Catalin Marinas Signed-off-by: Marc Zyngier --- arch/arm64/kvm/hyp/hyp-entry.S | 2 ++ 1 file changed, 2 insertions(+) (limited to 'arch/arm64/kvm/hyp') diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S index 8359fed89098..87dfecce82b1 100644 --- a/arch/arm64/kvm/hyp/hyp-entry.S +++ b/arch/arm64/kvm/hyp/hyp-entry.S @@ -212,6 +212,8 @@ ENDPROC(\label) .macro invalid_vect target .align 7 b \target + ldp x0, x1, [sp], #16 + b \target .endm ENTRY(__kvm_hyp_vector) -- cgit v1.2.3