From 8f7c0d8b23c3f5f740a48db31ebadef28af17a22 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 15 Sep 2022 13:11:17 +0200 Subject: [PATCH] x86/Kconfig: Add CONFIG_CALL_THUNKS In preparation for mitigating the Intel SKL RSB underflow issue in software, add a new configuration symbol which allows to build the required call thunk infrastructure conditionally. Signed-off-by: Thomas Gleixner Signed-off-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20220915111146.849523555@infradead.org --- arch/x86/Kconfig | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index f408fa8..e18963e7 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -2446,6 +2446,14 @@ config CC_HAS_SLS config CC_HAS_RETURN_THUNK def_bool $(cc-option,-mfunction-return=thunk-extern) +config HAVE_CALL_THUNKS + def_bool y + depends on RETHUNK && OBJTOOL + +config CALL_THUNKS + def_bool n + select FUNCTION_ALIGNMENT_16B + menuconfig SPECULATION_MITIGATIONS bool "Mitigations for speculative execution vulnerabilities" default y -- 2.7.4