[PATCH] kbuild: use -flive-patching when CONFIG_LIVEPATCH is enabled

[Miroslav Benes]

GCC 9 introduces a new option, -flive-patching. It disables certain
optimizations which could make a compilation unsafe for later live
patching of the running kernel.

The option is used only if CONFIG_LIVEPATCH is enabled and $(CC)
supports it.

Signed-off-by: Miroslav Benes <mbenes@xxxxxxx>
---
 Makefile | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Makefile b/Makefile
index a0650bf79606..53f5ab810efe 100644
--- a/Makefile
+++ b/Makefile
@@ -778,6 +778,10 @@ KBUILD_CFLAGS_KERNEL	+= $(call cc-option,-ffunction-sections,)
 KBUILD_CFLAGS_KERNEL	+= $(call cc-option,-fdata-sections,)
 endif
 
+ifdef CONFIG_LIVEPATCH
+KBUILD_CFLAGS += $(call cc-option, -flive-patching=inline-clone)
+endif
+
 # arch Makefile may override CC so keep this after arch Makefile is included
 NOSTDINC_FLAGS += -nostdinc -isystem $(shell $(CC) -print-file-name=include)
 
-- 
2.19.2