From af42f20480bf13d9dbf099ccca65f3de8c44fcaf Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Mon, 3 Apr 2017 19:38:05 +0100 Subject: [PATCH] arm64: hyp-stub: Zero x0 on successful stub handling We now return HVC_STUB_ERR when a stub hypercall fails, but we leave whatever was in x0 on success. Zeroing it on return seems like a good idea. Signed-off-by: Marc Zyngier Signed-off-by: Christoffer Dall --- arch/arm64/kernel/hyp-stub.S | 4 +++- arch/arm64/kvm/hyp-init.S | 6 +++--- 2 files changed, 6 insertions(+), 4 deletions(-) diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S index d55604d91e33..e1261fbaa374 100644 --- a/arch/arm64/kernel/hyp-stub.S +++ b/arch/arm64/kernel/hyp-stub.S @@ -73,8 +73,10 @@ el1_sync: /* Someone called kvm_call_hyp() against the hyp-stub... */ ldr x0, =HVC_STUB_ERR + eret -9: eret +9: mov x0, xzr + eret ENDPROC(el1_sync) .macro invalid_vector label diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S index 3734e6315cd7..839425c24b1c 100644 --- a/arch/arm64/kvm/hyp-init.S +++ b/arch/arm64/kvm/hyp-init.S @@ -154,13 +154,13 @@ reset: /* Install stub vectors */ adr_l x5, __hyp_stub_vectors msr vbar_el2, x5 - b exit + mov x0, xzr + eret 1: /* Bad stub call */ ldr x0, =HVC_STUB_ERR - -exit: eret + ENDPROC(__kvm_handle_stub_hvc) .ltorg