From 463f36c76fa4ec015c640ff63ccf52e7527abee0 Mon Sep 17 00:00:00 2001 From: Alexander Egorenkov Date: Fri, 16 Jul 2021 22:00:22 +0200 Subject: [PATCH] s390/boot: fix use of expolines in the DMA code The DMA code section of the decompressor must be compiled with expolines if Spectre V2 mitigation has been enabled for the decompressed kernel. This is required because although the decompressor's image contains the DMA code section, it is handed over to the decompressed kernel for use. Because the DMA code is already slow w/o expolines, use expolines always regardless whether the decompressed kernel is using them or not. This simplifies the DMA code by dropping the conditional compilation of expolines. Fixes: bf72630130c2 ("s390: use proper expoline sections for .dma code") Cc: # 5.2 Signed-off-by: Alexander Egorenkov Reviewed-by: Heiko Carstens Signed-off-by: Heiko Carstens --- arch/s390/boot/text_dma.S | 19 ++++--------------- 1 file changed, 4 insertions(+), 15 deletions(-) diff --git a/arch/s390/boot/text_dma.S b/arch/s390/boot/text_dma.S index f7c77cd518f2..5ff5fee02801 100644 --- a/arch/s390/boot/text_dma.S +++ b/arch/s390/boot/text_dma.S @@ -9,16 +9,6 @@ #include #include -#ifdef CC_USING_EXPOLINE - .pushsection .dma.text.__s390_indirect_jump_r14,"axG" -__dma__s390_indirect_jump_r14: - larl %r1,0f - ex 0,0(%r1) - j . -0: br %r14 - .popsection -#endif - .section .dma.text,"ax" /* * Simplified version of expoline thunk. The normal thunks can not be used here, @@ -27,11 +17,10 @@ __dma__s390_indirect_jump_r14: * affects a few functions that are not performance-relevant. */ .macro BR_EX_DMA_r14 -#ifdef CC_USING_EXPOLINE - jg __dma__s390_indirect_jump_r14 -#else - br %r14 -#endif + larl %r1,0f + ex 0,0(%r1) + j . +0: br %r14 .endm /* -- GitLab