The following commit has been merged into the x86/core branch of tip: Commit-ID: 8f7c0d8b23c3f5f740a48db31ebadef28af17a22 Gitweb: https://git.kernel.org/tip/8f7c0d8b23c3f5f740a48db31ebadef28af17a22 Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx> AuthorDate: Thu, 15 Sep 2022 13:11:17 +02:00 Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx> CommitterDate: Mon, 17 Oct 2022 16:41:10 +02:00 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 <tglx@xxxxxxxxxxxxx> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20220915111146.849523555@xxxxxxxxxxxxx --- arch/x86/Kconfig | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index f408fa8..e18963e 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
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