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authorAlexander Egorenkov <egorenar@linux.ibm.com>2021-07-16 22:00:22 +0200
committerHeiko Carstens <hca@linux.ibm.com>2021-07-20 17:59:40 +0200
commit463f36c76fa4ec015c640ff63ccf52e7527abee0 (patch)
treeb66eda85923c2748e4322c930fea814260b07705
parentf8c2602733c953ed7a16e060640b8e96f9d94b9b (diff)
downloadlinux-463f36c76fa4ec015c640ff63ccf52e7527abee0.tar.bz2
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: <stable@vger.kernel.org> # 5.2 Signed-off-by: Alexander Egorenkov <egorenar@linux.ibm.com> Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
-rw-r--r--arch/s390/boot/text_dma.S19
1 files 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 <asm/errno.h>
#include <asm/sigp.h>
-#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
/*