4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Peter Zijlstra <pet...@infradead.org>

commit d5028ba8ee5a18c9d0bb926d883c28b370f89009 upstream.

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) <pet...@infradead.org>
Acked-by: Thomas Gleixner <t...@linutronix.de>
Cc: Andy Lutomirski <l...@kernel.org>
Cc: Arjan van de Ven <ar...@linux.intel.com>
Cc: Borislav Petkov <b...@alien8.de>
Cc: Dan Williams <dan.j.willi...@intel.com>
Cc: Dave Hansen <dave.han...@linux.intel.com>
Cc: David Woodhouse <dw...@infradead.org>
Cc: Greg Kroah-Hartman <gre...@linuxfoundation.org>
Cc: Josh Poimboeuf <jpoim...@redhat.com>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: Peter Zijlstra <pet...@infradead.org>
Signed-off-by: Ingo Molnar <mi...@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

---
 Makefile               |    5 +++++
 arch/x86/Kconfig       |    1 +
 arch/x86/Makefile      |   10 +++-------
 scripts/Makefile.build |    2 ++
 4 files changed, 11 insertions(+), 7 deletions(-)

--- a/Makefile
+++ b/Makefile
@@ -494,6 +494,11 @@ KBUILD_CFLAGS += $(CLANG_TARGET) $(CLANG
 KBUILD_AFLAGS += $(CLANG_TARGET) $(CLANG_GCC_TC)
 endif
 
+RETPOLINE_CFLAGS_GCC := -mindirect-branch=thunk-extern 
-mindirect-branch-register
+RETPOLINE_CFLAGS_CLANG := -mretpoline-external-thunk
+RETPOLINE_CFLAGS := $(call cc-option,$(RETPOLINE_CFLAGS_GCC),$(call 
cc-option,$(RETPOLINE_CFLAGS_CLANG)))
+export RETPOLINE_CFLAGS
+
 ifeq ($(config-targets),1)
 # ===========================================================================
 # *config targets only - make sure prerequisites are updated, and descend
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -431,6 +431,7 @@ 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
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -232,13 +232,9 @@ KBUILD_CFLAGS += -fno-asynchronous-unwin
 
 # Avoid indirect branches in kernel to deal with Spectre
 ifdef CONFIG_RETPOLINE
-    RETPOLINE_CFLAGS_GCC := -mindirect-branch=thunk-extern 
-mindirect-branch-register
-    RETPOLINE_CFLAGS_CLANG := -mretpoline-external-thunk
-
-    RETPOLINE_CFLAGS += $(call cc-option,$(RETPOLINE_CFLAGS_GCC),$(call 
cc-option,$(RETPOLINE_CFLAGS_CLANG)))
-    ifneq ($(RETPOLINE_CFLAGS),)
-        KBUILD_CFLAGS += $(RETPOLINE_CFLAGS) -DRETPOLINE
-    endif
+ifneq ($(RETPOLINE_CFLAGS),)
+  KBUILD_CFLAGS += $(RETPOLINE_CFLAGS) -DRETPOLINE
+endif
 endif
 
 archscripts: scripts_basic
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -272,8 +272,10 @@ else
 objtool_args += $(call cc-ifversion, -lt, 0405, --no-unreachable)
 endif
 ifdef CONFIG_RETPOLINE
+ifneq ($(RETPOLINE_CFLAGS),)
   objtool_args += --retpoline
 endif
+endif
 
 
 ifdef CONFIG_MODVERSIONS


Reply via email to