[RFC v5 56/57] arm64: entry: Avoid empty alternatives entries

From: Julien Thierry
Date: Thu Jan 09 2020 - 11:10:17 EST


kernel_ventry will create alternative entries to potentially replace
0 instructions with 0 instructions for EL1 vectors. While this does not
cause an issue, it pointlessly takes up some bytes in the alternatives
section.

Do not generate such entries.

Signed-off-by: Julien Thierry <jthierry@xxxxxxxxxx>
---
arch/arm64/kernel/entry.S | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 7c6a0a41676f..605bb7cbe499 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -60,16 +60,16 @@
.macro kernel_ventry, el, label, regsize = 64
.align 7
#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
-alternative_if ARM64_UNMAP_KERNEL_AT_EL0
.if \el == 0
+alternative_if ARM64_UNMAP_KERNEL_AT_EL0
.if \regsize == 64
mrs x30, tpidrro_el0
msr tpidrro_el0, xzr
.else
mov x30, xzr
.endif
- .endif
alternative_else_nop_endif
+ .endif
#endif

sub sp, sp, #S_FRAME_SIZE
--
2.21.0