Commit-ID: b4879c9b99a43e6c580d563f292a569a016af2a4 Gitweb: https://git.kernel.org/tip/b4879c9b99a43e6c580d563f292a569a016af2a4 Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx> AuthorDate: Tue, 6 Feb 2018 09:46:13 +0100 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitDate: Wed, 21 Feb 2018 09:05:05 +0100 objtool, retpolines: Integrate objtool with retpoline support more closely Disable retpoline validation in objtool if your compiler sucks, and otherwise select the validation stuff for CONFIG_RETPOLINE=y (most builds would already have it set due to ORC). Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Acked-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: Andy Lutomirski <luto@xxxxxxxxxx> Cc: Arjan van de Ven <arjan@xxxxxxxxxxxxxxx> Cc: Borislav Petkov <bp@xxxxxxxxx> Cc: Dan Williams <dan.j.williams@xxxxxxxxx> Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> Cc: David Woodhouse <dwmw2@xxxxxxxxxxxxx> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> --- Makefile | 5 +++++ arch/x86/Kconfig | 1 + scripts/Makefile.build | 2 ++ 3 files changed, 8 insertions(+) diff --git a/Makefile b/Makefile index 79ad2bf..2ad6ff6 100644 --- a/Makefile +++ b/Makefile @@ -489,6 +489,11 @@ KBUILD_CFLAGS += $(CLANG_TARGET) $(CLANG_GCC_TC) KBUILD_AFLAGS += $(CLANG_TARGET) $(CLANG_GCC_TC) endif +ifneq ($(call cc-option,-mindirect-branch=thunk-extern -mindirect-branch-register),) + CC_HAS_RETPOLINE := 1 +endif +export CC_HAS_RETPOLINE + ifeq ($(config-targets),1) # =========================================================================== # *config targets only - make sure prerequisites are updated, and descend diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 63bf349..c1aed6c 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -436,6 +436,7 @@ config GOLDFISH config RETPOLINE bool "Avoid speculative indirect branches in kernel" default y + select STACK_VALIDATION if HAVE_STACK_VALIDATION help Compile kernel with the retpoline compiler options to guard against kernel-to-user data leaks by avoiding speculative indirect diff --git a/scripts/Makefile.build b/scripts/Makefile.build index ce0fc4d..07e5802 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -267,8 +267,10 @@ else objtool_args += $(call cc-ifversion, -lt, 0405, --no-unreachable) endif ifdef CONFIG_RETPOLINE +ifdef CC_HAS_RETPOLINE objtool_args += --retpoline endif +endif ifdef CONFIG_MODVERSIONS -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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