From: Alexander Egorenkov egorenar@linux.ibm.com
stable inclusion from stable-5.10.54 commit 37a88b41dc29438e406e4a40ef7e3159a5139e30 bugzilla: 175586 https://gitee.com/openeuler/kernel/issues/I4DVDU
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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commit 463f36c76fa4ec015c640ff63ccf52e7527abee0 upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Chen Jun chenjun102@huawei.com Acked-by: Weilong Chen chenweilong@huawei.com Signed-off-by: Chen Jun chenjun102@huawei.com --- 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 <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
/*