From 00a44cdaba0900c63a003e0c431f506f49376a90 Mon Sep 17 00:00:00 2001 From: James Morse Date: Wed, 27 Apr 2016 17:47:02 +0100 Subject: [PATCH] arm64: kvm: Move lr save/restore from do_el2_call into EL1 Today the 'hvc' calling KVM or the hyp-stub is expected to preserve all registers. KVM saves/restores the registers it needs on the EL2 stack using do_el2_call(). The hyp-stub has no stack, later patches need to be able to be able to clobber the link register. Move the link register save/restore to the the call sites. Signed-off-by: James Morse Acked-by: Marc Zyngier Signed-off-by: Will Deacon --- arch/arm64/kernel/hyp-stub.S | 10 ++++++++-- arch/arm64/kvm/hyp.S | 7 ++++++- arch/arm64/kvm/hyp/hyp-entry.S | 6 ++---- 3 files changed, 16 insertions(+), 7 deletions(-) diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S index a272f335c289..7eab8acbbbd9 100644 --- a/arch/arm64/kernel/hyp-stub.S +++ b/arch/arm64/kernel/hyp-stub.S @@ -101,10 +101,16 @@ ENDPROC(\label) */ ENTRY(__hyp_get_vectors) + str lr, [sp, #-16]! mov x0, xzr - // fall through -ENTRY(__hyp_set_vectors) hvc #0 + ldr lr, [sp], #16 ret ENDPROC(__hyp_get_vectors) + +ENTRY(__hyp_set_vectors) + str lr, [sp, #-16]! + hvc #0 + ldr lr, [sp], #16 + ret ENDPROC(__hyp_set_vectors) diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S index 48f19a37b3df..4ee5612f43ea 100644 --- a/arch/arm64/kvm/hyp.S +++ b/arch/arm64/kvm/hyp.S @@ -38,13 +38,18 @@ * A function pointer with a value of 0 has a special meaning, and is * used to implement __hyp_get_vectors in the same way as in * arch/arm64/kernel/hyp_stub.S. + * HVC behaves as a 'bl' call and will clobber lr. */ ENTRY(__kvm_call_hyp) -alternative_if_not ARM64_HAS_VIRT_HOST_EXTN +alternative_if_not ARM64_HAS_VIRT_HOST_EXTN + str lr, [sp, #-16]! hvc #0 + ldr lr, [sp], #16 ret alternative_else b __vhe_hyp_call nop + nop + nop alternative_endif ENDPROC(__kvm_call_hyp) diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S index 3488894397ff..43b4b28159d9 100644 --- a/arch/arm64/kvm/hyp/hyp-entry.S +++ b/arch/arm64/kvm/hyp/hyp-entry.S @@ -42,19 +42,17 @@ * Shuffle the parameters before calling the function * pointed to in x0. Assumes parameters in x[1,2,3]. */ - sub sp, sp, #16 - str lr, [sp] mov lr, x0 mov x0, x1 mov x1, x2 mov x2, x3 blr lr - ldr lr, [sp] - add sp, sp, #16 .endm ENTRY(__vhe_hyp_call) + str lr, [sp, #-16]! do_el2_call + ldr lr, [sp], #16 /* * We used to rely on having an exception return to get * an implicit isb. In the E2H case, we don't have it anymore. -- 2.11.4.GIT