[PULL 36/79] arm64: hyp-stub: Stop pointlessly clobbering lr

[Christoffer Dall]

From: Marc Zyngier <marc.zyngier at arm.com>

When entering the kernel hyp stub, we check whether or not we've
made it here through an HVC instruction, clobbering lr (aka x30)
in the process.

This is completely pointless, as HVC is the only way to get here
(all traps to EL2 are disabled, no interrupt override is applied).

So let's remove this bit of code whose only point is to corrupt
a valuable register.

Acked-by: Catalin Marinas <catalin.marinas at arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier at arm.com>
Signed-off-by: Christoffer Dall <cdall at linaro.org>
---
 arch/arm64/kernel/hyp-stub.S | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S
index d3b5f75..e4215ad 100644
--- a/arch/arm64/kernel/hyp-stub.S
+++ b/arch/arm64/kernel/hyp-stub.S
@@ -55,12 +55,6 @@ ENDPROC(__hyp_stub_vectors)
 	.align 11
 
 el1_sync:
-	mrs	x30, esr_el2
-	lsr	x30, x30, #ESR_ELx_EC_SHIFT
-
-	cmp	x30, #ESR_ELx_EC_HVC64
-	b.ne	9f				// Not an HVC trap
-
 	cmp	x0, #HVC_GET_VECTORS
 	b.ne	1f
 	mrs	x0, vbar_el2
-- 
2.9.0