x86/msr: Add definitions for new speculation control MSRs

[mirror_ubuntu-artful-kernel.git] / arch / x86 / Kconfig

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index debe0de398dfbcda87342e6cc3f4f347e95c5654..e6b0183dc28f6b052d3b06595440aea66e0211ff 100644 (file)
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -425,6 +425,19 @@ config GOLDFISH
        def_bool y
        depends on X86_GOLDFISH
 
+config RETPOLINE
+       bool "Avoid speculative indirect branches in kernel"
+       default y
+       help
+         Compile kernel with the retpoline compiler options to guard against
+         kernel-to-user data leaks by avoiding speculative indirect
+         branches. Requires a compiler with -mindirect-branch=thunk-extern
+         support for full protection. The kernel may run slower.
+
+         Without compiler support, at least indirect branches in assembler
+         code are eliminated. Since this includes the syscall entry path,
+         it is not entirely pointless.
+
 config INTEL_RDT
        bool "Intel Resource Director Technology support"
        default n