Messages in this thread Patch in this message | | | From | Andi Kleen <> | Subject | [PATCH v2 09/12] x86/retpoline: Finally enable retpoline for C code | Date | Wed, 3 Jan 2018 18:00:16 -0800 |
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From: Dave Hansen <dave.hansen@linux.intel.com>
From: David Woodhouse <dwmw@amazon.co.uk>
Add retpoline compile option in Makefile
Update Makefile with retpoline compile options. This requires a gcc with the retpoline compiler patches enabled.
Print a warning when the compiler doesn't support retpoline
[Originally from David and Tim, but hacked by AK]
v2: Use CONFIG option to enable Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com> --- arch/x86/Makefile | 11 +++++++++++ 1 file changed, 11 insertions(+)
diff --git a/arch/x86/Makefile b/arch/x86/Makefile index 3e73bc255e4e..b02e35350244 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -230,6 +230,17 @@ KBUILD_CFLAGS += -Wno-sign-compare # KBUILD_CFLAGS += -fno-asynchronous-unwind-tables +# +ifdef CONFIG_RETPOLINE + RETPOLINE_CFLAGS += $(call cc-option,-mindirect-branch=thunk-extern) + ifneq ($(RETPOLINE_CFLAGS),) + KBUILD_CFLAGS += $(RETPOLINE_CFLAGS) -DRETPOLINE + KBUILD_AFLAGS += -DRETPOLINE + else + $(warning Retpoline not supported in compiler. System may be insecure.) + endif +endif + archscripts: scripts_basic $(Q)$(MAKE) $(build)=arch/x86/tools relocs -- 2.14.3
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