From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 From: Arjan van de Ven Date: Thu, 8 Feb 2018 16:49:38 +0000 Subject: [PATCH] zero extra registers This for Zero used caller-saved general registers upon function return. --- arch/x86/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/Makefile b/arch/x86/Makefile index 94df0868804b..083a97af538c 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -216,7 +216,7 @@ KBUILD_CFLAGS += -fno-asynchronous-unwind-tables # Avoid indirect branches in kernel to deal with Spectre ifdef CONFIG_RETPOLINE - KBUILD_CFLAGS += $(RETPOLINE_CFLAGS) + KBUILD_CFLAGS += $(RETPOLINE_CFLAGS) -mzero-caller-saved-regs=used # Additionally, avoid generating expensive indirect jumps which # are subject to retpolines for small number of switch cases. # clang turns off jump table generation by default when under -- https://clearlinux.org