[PATCH v5 01/34] arm64: hyp-stub: Stop pointlessly clobbering lr
Marc Zyngier
marc.zyngier at arm.com
Mon Apr 3 11:37:34 PDT 2017
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>
---
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 d3b5f75e652e..e4215ad06930 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
--
2.11.0
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