[patch 14/38] x86/Kconfig: Add CONFIG_CALL_THUNKS

Thomas Gleixner
2022-07-16T23:18:14Z

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@linutronix.de>
---
arch/x86/Kconfig | 8 ++++++++
1 file changed, 8 insertions(+)

--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -2439,6 +2439,14 @@ 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 MODULE_ALLOC
+
menuconfig SPECULATION_MITIGATIONS
bool "Mitigations for speculative execution vulnerabilities"
default y