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

Julien Thierry jthierry at redhat.com
Thu Jan 9 08:02:59 PST 2020


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 at redhat.com>
---
 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




More information about the linux-arm-kernel mailing list